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Lorenzo TASSI
Professore Associato
Dipartimento di Scienze Chimiche e Geologiche - Sede Dipartimento di Scienze Chimiche e Geologiche
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Pubblicazioni
2023
- Characterization of Some Stilbenoids Extracted from Two Cultivars of Lambrusco-Vitis vinifera Species: An Opportunity to Valorize Pruning Canes for a More Sustainable Viticulture
[Articolo su rivista]
D'Eusanio, Veronica; Genua, Francesco; Marchetti, Andrea; Morelli, Lorenzo; Tassi, Lorenzo
abstract
Pruning canes from grape vines are valuable byproducts that contain resveratrol and other health-boosting stilbenoids. This study aimed to assess the effect of roasting temperature on the stilbenoid content of vine canes by comparing two Vitis vinifera cultivars, Lambrusco Ancellotta and Salamino. Samples were collected during different phases of the vine plant cycle. One set was collected in September after the grape harvest and was air-dried and analyzed. A second set was obtained during vine pruning in February and evaluated immediately after collection. The main stilbenoid identified in each sample was resveratrol (similar to 100-2500 mg/kg), with significant levels of viniferin (similar to 100-600 mg/kg) and piceatannol (similar to 0-400 mg/kg). Their contents decreased with increasing roasting temperature and residence time on the plant. This study provides valuable insights into the use of vine canes in a novel and efficient manner, which could potentially benefit different industries. One potential use involves the roasted cane chips to accelerate the aging of vinegars and alcoholic beverages. This method is more efficient and cost-effective than traditional aging, which is slow and unfavorable from an industrial perspective. Furthermore, incorporating vine canes into maturation processes reduces viticulture waste and enhances the final products with health-promoting molecules, such as resveratrol.
2023
- Exploring the Mineral Composition of Grapevine Canes for Wood Chip Applications in Alcoholic Beverage Production to Enhance Viticulture Sustainability
[Articolo su rivista]
D'Eusanio, Veronica; Genua, Francesco; Marchetti, Andrea; Morelli, Lorenzo; Tassi, Lorenzo
abstract
2023
- Rosaceae Nut-Shells as Sustainable Aggregate for Potential Use in Non-Structural Lightweight Concrete
[Articolo su rivista]
D’Eusanio, Veronica; Bertacchini, Lucia; Marchetti, Andrea; Mariani, Mattia; Pastorelli, Stefano; Silvestri, Michele; Tassi, Lorenzo
abstract
2023
- Volatile Aroma Compounds of Gavina® Watermelon (Citrullus Lanatus L.) Dietary Fibers to Increase Food Sustainability
[Articolo su rivista]
D'Eusanio, Veronica; Maletti, Laura; Marchetti, Andrea; Roncaglia, Fabrizio; Tassi, Lorenzo
abstract
2023
- Waste By-Product of Grape Seed Oil Production: Chemical Characterization for Use as a Food and Feed Supplement
[Articolo su rivista]
D'Eusanio, Veronica; Malferrari, Daniele; Marchetti, Andrea; Roncaglia, Fabrizio; Tassi, Lorenzo
abstract
2022
- Candying process for enhancing pre-waste watermelon rinds to increase food sustainability
[Articolo su rivista]
Maletti, Laura; D'Eusanio, Veronica; Lancellotti, Lisa; Marchetti, Andrea; Pincelli, Luca; Strani, Lorenzo; Tassi, Lorenzo
abstract
This work describes two alternative laboratory methods ’candying fruit’ methods of fresh mesocarp of Crimson
sweet watermelon, a typical waste and unappetizing material. Our experimental candying process was conducted
by slow osmosis, lasting 24 weeks at room temperature. It was activated with granular sucrose according to our
two alternative laboratory methods, WET and DRY. Fresh watermelon rinds were transformed into candied fruit
with excellent flavor and aromas. The aromatic profile of all the materials was characterized with HS-SPME-GC–
MS technique. The results highlighted some significant differences in the Volatile Organic Compounds fraction,
probably attributable both to the cultivar and to the two candying methods, as verified also by a panel test. The
class of alcohols remains almost constant in all the samples. Terpenoids are highly present in FRESH samples,
while they disappear in DRY candied ones. Acetate esters are absent in FRESH rinds, they reach the maximum
level in WET, and stop at the middle in DRY samples. The trend of the values relating to the class of acids is
opposite: absent in the FRESH aromatic profile, maximum and average for DRY and WET samples, respectively.
2022
- Comparative Analysis of VOCs from Winter Melon Pomace Fibers before and after Bleaching Treatment with H2O2
[Articolo su rivista]
Maletti, Laura; D'Eusanio, Veronica; Durante, Caterina; Marchetti, Andrea; Pincelli, Luca; Tassi, Lorenzo
abstract
In this study, the trend of Volatile Organic Compounds (VOCs) in dietary fiber samples from the winter melon (Cucumis Melo var. Inodorus, Yellow Canary type) were investigated. This foodstuff, obtained as a by-product of agri-food production, has gained increasing attention and is characterized by many bioactive components and a high dietary-fiber content. As regards fiber, it is poorly colored, but it may be whitened by applying a bleaching treatment with H2O2. The result is a fibrous material for specific applications in food manufacturing, for example, as a corrector for some functional and technological properties. This treatment is healthy and safe for consumers and widely applied in industrial food processes. In this study, a method based on headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC-MS) was applied for the characterization of the aromatic profile of the dried raw materials. Furthermore, VOC variation was investigated as function of the bleaching treatment with H2O2. The bleached samples were also analyzed after a long storage period (24 months), to assess their stability over time. As a result, the VOC fraction of the fresh raw fiber showed nine classes of analytes; these were restricted to seven for the bleached fiber at t0 time, and further reduced to four classes at the age of 24 months. Alcohols were the main group detected in the fresh raw sample (33.8 % of the total chromatogram area), with 2,3-butanediol isomers as the main compounds. These analytes decreased with time. An opposite trend was observed for the acids (9.7% at t0), which increased with time and became the most important class in the 24-month aged and bleached sample (57.3%).
2022
- VOCs Analysis of Three Different Cultivars of Watermelon (Citrullus lanatus L.) Whole Dietary Fiber
[Articolo su rivista]
Maletti, Laura; D'Eusanio, Veronica; Durante, Caterina; Marchetti, Andrea; Tassi, Lorenzo
abstract
In this study, the trend of VOCs of dietary fiber samples, coming from three different watermelon cultivars Citrullus lanatus L. (variety Gavina®®, Crimson sweet, and Asahi myiako) was investigated. This foodstuff, obtained as a by-product of residual agri-food production, has gained increasing attention because of its many bioactive components and high dietary fiber content. The result is a fibrous material for specific applications in food manufacturing, such as corrector for some functional and technological properties. In this study, a method based on headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography–mass spectrometry (GC–MS) was used to characterize the aromatic profiles of the dried raw materials. Therefore, the VOCs of the samples of the three cultivars were investigated. Experimental results have shown that watermelon fibers generate VOCs, which can be grouped into six common classes of analytes. The different distributions of the identified compounds made it possible to effectively differentiate the three cultivars studied based on their peculiar aroma profiles. In particular, Gavina®® fiber is distinguished by the high content of terpenes, Asahi myiako by the presence of aldehydes generated as fatty acid metabolites, and Crimson sweet by the higher content of acetyl esters.
2021
- 87Sr/86Sr ratio as traceability marker for Modena's balsamic vinegars
[Articolo su rivista]
Durante, C.; Lancellotti, L.; Manzini, D.; Rossi, M. C.; Sighinolfi, S.; Marchetti, A.; Tassi, L.
abstract
Geographical origin and authenticity of food are topics of interest for both consumers and producers. Among the different indicators used for traceability studies, n(87Sr)/n(86Sr) isotopic ratio has provided excellent results. In this study, the production chains of the balsamic vinegars of the Modena province, the Aceto Balsamico Tradizionale di Modena (ABTM) and the industrially made Aceto Balsamico di Modena (ABM) were investigated by using the n(87Sr)/n(86Sr) indicator. The geographical origin of the starting raw materials for the ABM production was investigated, as well as the variability of ABM samples of different production years, namely 2009, 2010, 2011 and 2014. The results show no significant variability among ABM samples of different production years and highlight the possibility to distinguish this product from the ABTM. Furthermore, the investigated indicator also confirms an objective link of the food with its starting raw material and the territory of origin of the grapes, assessing the discriminating power of n(87Sr)/n(86Sr) ratio for geographical traceability studies.
2021
- Analytical Concentrations of Some Elements in Seeds and Crude Extracts from Aesculus hippocastanum, by ICP-OES Technique
[Articolo su rivista]
Durante, C.; Cocchi, M.; Lancellotti, L.; Maletti, L.; Marchetti, A.; Sighinolfi, S.; Tassi, L.; Roncaglia, F.
abstract
The metal content in some samples of horse chestnut seeds (Aesculus hippocastanum) was monitored over time (years 2016, 2017, 2018, 2019) considering the two most common and representative Mediterranean varieties: the pure species (AHP, which gives white flowers) and a hybrid one (AHH, which gives pink flowers). The selected elemental composition of the samples was determined by applying the ICP-OES technique.
Several samples obtained from different preliminary treatments of the peeled seeds were examined, such as: i) floury samples (wild type) mineralized with the wet method; ii) the ashes of both AHP and AHH varieties; iii) the fraction of total inorganic soluble salts (TISS).
Furthermore, the hydroalcoholic crude extracts (as a tincture) were obtained according to the official Pharmacopoeia methods, and the relevant results were compared with those of a commercial sample, an herbal product - food supplement of similar characteristics. The main characteristics of this research work underline that the two botanical varieties give different distinctive characters, due to the Fe content (80.05 vs 1.42 mg / 100 g d.s., for AHP and AHH - wild type flour samples, respectively), along with K, Ca, Mn, Ni and Cu, which are more abundant in the AHP samples. Furthermore, the PCA analysis was applied to the experimental dataset in order to classify and discriminate the samples, in relation to their similar botanical origin, but different for the color of the bloom. These results can be useful for the traceability of raw materials potentially intended for the production of auxiliary systems of pharmacological interest.
2021
- Tracing geographical origin of Lambrusco PDO wines using isotope ratios of oxygen, boron, strontium, lead and their elemental concentration
[Articolo su rivista]
Lancellotti, L.; Sighinolfi, S.; Ulrici, A.; Maletti, L.; Durante, C.; Marchetti, A.; Tassi, L.
abstract
Wine identification is one of the most important aspects in the classification of wines and consumer protection. In particular, assuring wine authenticity is a crucial issue on which researchers are focusing on. This study aims to evaluate the feasibility of using chemical (B, Pb and Sr concentration) and isotopic compositions (δ11B, 20yPb/20xPb, 87Sr/86Sr and δ18O) of wine samples to trace their geographic origins. Different PDO Lambrusco wines coming from a confined area of northern Italy were analyzed and all the isotopic systematics were monitored by using a multi collector inductively coupled plasma mass spectrometer (MC-ICP/MS). The obtained results showed that boron isotope ratio measurements led to a satisfactory degree of accuracy and precision (measured value, n = 28, 11B/10B of NIST SRM 951a equal to 4.04343 ± 0.00178, (u = 2s) with a certified value of 4.04362 ± 0.00136 (u = 2s). Furthermore, in the present study, it has been possible to highlight significant differences among samples by means of one-way analysis of variance (ANOVA) and post hoc Tukey-Kramer test. Finally, Principal Component Analysis (PCA) was also carried out in order to evaluate to which extent the different PDOs can be distinguished from each other, taking into account the whole set of geographical origin descriptors. Although δ11B provided more sensitive information, the obtained results highlighted the important to consider the synergistic combination of all the investigated parameters to trace the different samples and the need to combine the obtained values with the same parameters evaluated in the soil, water and fertilizer as well.
2020
- Red horse-chestnut of Aesculus X Carnea : a new way for health and food design?
[Capitolo/Saggio]
Baraldi, Cecilia; Foca, Giorgia; Maletti, Laura; Marchetti, Andrea; Roncaglia, Fabrizio; Sighinolfi, Simona; Tassi, Lorenzo
abstract
Some investigations have been performed about the composition of Aesculus X carnea seeds (Red horse-chestnuts). Different experimental techniques have been used to gain more information on morphological structure and proximate chemical composition of this product. Surface analysis by SEM showed internal typical structure of globular-form bodies, containing starch, lipids, proteins, mineral components and many others species, confined in cell walls and cemented by a gelled hydrocolloid. The most representative data related to the chemical composition of naturally desiccated specimen are as follows: proteins 3.16%; lipids 4.34%; total glucides 15.6%. Obviously, this chemical faces modulate some other undifferentiated chemical parameters, such as Cold Water Solubility (CWS = 53.9%), and Total Inorganic Soluble Salts (TISS = 2.79%). A stringent comparison of the present findings has been made with our previous results obtained by working with the seeds of two Hippocastanaceae parent cultivars.
2020
- Use of lead isotopic ratios as geographical tracer for Lambrusco PDO wines
[Articolo su rivista]
Lancellotti, L.; Sighinolfi, S.; Marchetti, A.; Tassi, L.
abstract
In this study, the lead isotope signature was tested with the aim to verify its potential as geographic tracer for wine production and particularly for the Lambrusco PDO wines of the province of Modena (Italy). A solid phase extraction procedure, for separating lead from the investigated matrices, soil and wine, was optimized. Furthermore, different mathematical models, based on an exponential law and internal or external correction approach, were evaluated for the correction of instrumental mass dependent fractionation. The optimized analytical procedure yielded isotopic ratio data relative to the lead NIST 981 standard, 208Pb/206Pb = 2.16664 and 207Pb/206Pb = 0.914645, in good agreement both with the tabulated values and with the most recent literature data. Measured isotope ratio data highlight the contribute of multiple lead sources in bottled wine but different from the one present in soils.
2019
- DA PLACENTIA AD ARIMINUM: TECNICHE E MATERIALI DELLA PITTURA MURALE ROMANA
NELLE DOMUS DELLA OCTAVA REGIO
Pitture frammentarie di epoca romana da Roma e dal Lazio: nuove ricerche
[Articolo su rivista]
Baraldi, Pietro; Baraldi, Cecilia; Ferrari, Giorgia; Tassi, Lorenzo; Zannini, Paolo
abstract
The analyses of polychrome plaster from the Octava Regio of ancient Roman Italy have enabled the identification
of the palette of pigments used, the pictorial techniques and the different ways of decorating painted
surfaces. Despite the short distances between the towns founded along the Via Aemilia, the paintings exhibit
differences relating to these important domus: the decorative motifs, pigments, intonachinos and plaster all
vary. Some of the more unusual pigments may come from geological features found in the territory or from
the nearby mountains.
2019
- INDURENTI NON MIGRATORI PER MATERIALI PROTEICI
[Brevetto]
Foca, Giorgia; Leoni, Diego; Lusvardi, Gigliola; Marchetti, Andrea; Roncaglia, Fabrizio; Tassi, Lorenzo
abstract
L’invenzione è relativa ad un processo di preparazione di nuovi materiali copolimerici a base di proteine di origine animale e di origine vegetale, indurite mediante agenti reticolanti a struttura furanica recanti gruppi funzionali carbonilici. Il processo produttivo dei biopolimeri consiste nella preparazione di una soluzione / sospensione delle proteine in ambiente acquoso per ottenere la massima distensione delle micelle, eventualmente miscelate con coloranti o pigmenti finemente dispersi, cui si aggiunge infine un agente cross-linkante di tipo furanico solubilizzato o sospeso in un solvente non acquoso e sotto vigorosa agitazione. I prodotti copolimerici termoindurenti ottenibili presentano caratteristiche meccaniche e prestazionali analoghe a quelle della galalite, e sono privi di qualunque rilascio di VOC.
2019
- Organic Electrochemical Synthesis of hydrovanilloin, a new bioavailable nontoxic substitute of bisphenol A
[Relazione in Atti di Convegno]
Lancellotti, Lidia; Maletti, Laura; Borsari, Marco; Roncaglia, Fabrizio; Tassi, Lorenzo
abstract
2019
- Valorization of agri-food residues from industrial processes
[Relazione in Atti di Convegno]
Maletti, Laura; D’Eusanio, Veronica; Lancellotti, Lidia; Lancellotti, Lisa; Tassi, Lorenzo
abstract
2019
- Valorization of cucurbitaceae residues from primary agronomic productions
[Relazione in Atti di Convegno]
D’Eusanio, Veronica; Lancellotti, Lidia; Lancellotti, Lisa; Maletti, Laura; Sighinolfi, Simona; Tassi, Lorenzo
abstract
2018
- Determination of glycerol carbon stable isotope ratio for the characterization of Italian balsamic vinegars
[Articolo su rivista]
Sighinolfi, Simona; Baneschi, Ilaria; Manzini, Simona; Tassi, Lorenzo; Dallai, Luigi; Marchetti, Andrea
abstract
The gas chromatographic-combustion-isotopic ratio mass spectrometry (GC-C-IRMS) approach was applied to
determine the compound-specific 13C/12C isotopic ratio of glycerol in balsamic vinegars of Modena (Italy). In
particular, Italian Protected Designation of Origin and Protected Geographical Indication balsamic vinegars,
namely the traditionally made Aceto Balsamico Tradizionale di Modena (ABTM) and the industrial Aceto
Balsamico di Modena (ABM) products, were analyzed and a first attempt at classification was carried out. The
carbon isotopic ratio of the glycerol polyalcohol varies on the basis of origin, varietal or provenance; therefore
the discriminating potentiality of this species might be useful to elucidate the balsamic vinegar production
process. To do this, a preliminary study was conducted and several marketable products, ABTM and ABM type,
were subjected to measurements in addition to samples coming from three ABTM cask series (batteria).
Experimental results highlighted the peculiarities of the two different production processes, suggesting the use of
the carbon isotopic ratio of glycerol as an additional tool for balsamic vinegar authentication.
2018
- Development of 87Sr/86Sr maps as targeted strategy to support wine quality
[Articolo su rivista]
Durante, Caterina; Bertacchini, Lucia; Cocchi, Marina; Manzini, Daniela; Marchetti, Andrea; Rossi, Maria Cecilia; Sighinolfi, Simona; Tassi, Lorenzo
abstract
This study summarizes the results obtained from a systematic and long-term project aimed at the development
of tools to assess the provenance of food in the oenological sector. In particular, 87Sr/86Sr isotope ratios were
measured on statistically representative set of soils, vine branches and wines sampled in the production district
of Modena, worldwide known for the Lambrusco wines production. The obtained data were used to build strontium
isotopic maps able to objectively support the Lambrusco PDO wines origin as well as other products of the
Modena district.
Finally, a strong relationship was found between the 87Sr/86Sr isotope ratios of soils and vine branches on a
large scale, highlighting and confirming once more the idea that plants can also represent an optimal sampling
device to support geographical traceability.
2018
- Influence of Chemical and Physical Variables on 87Sr/86Sr Isotope Ratios Determination for Geographical Traceability Studies in the Oenological Food Chain
[Articolo su rivista]
Sighinolfi, Simona; Durante, Caterina; Lancellotti, Lisa; Tassi, Lorenzo; Marchetti, Andrea
abstract
This study summarizes the results obtained from a systematic and long-term project aimed at the development of tools to assess the provenance of food in the oenological sector. 87Sr/86Sr isotope ratios were measured on a representative set of soils, branches, and wines sampled from the Chianti Classico wine production area. In particular, owing to the high spatial resolution of the 87Sr/86Sr ratio in the topsoil, the effect of two mill techniques for soil pretreatment was investigated to verify the influence of the particle dimension on the measured isotopic ratios. Samples with particle sizes ranging from 250 to less than 50 m were investigated, and the extraction was performed by means of the DIN 19730 procedure. For each sample, the Sr isotope ratio was determined as well. The obtained results showed that the 87Sr/86Sr ratio is not influenced by soil particle size and may represent an effective tool as a geographic provenance indicator for the investigated product.
2018
- Le pitture parietali delle ville di Stabia: materiali e degrado
[Poster]
Baraldi, P.; Zannini, P.; Baraldi, C.; Tassi, L.; Rossi, A.; Troisi, G.
abstract
A partire dal 2009 con una serie di missioni in area stabiana, dopo il rilascio dei permessi da parte della Soprintendenza archeologica di Napoli e Pompei, sono state attuate indagini sulle pitture murali delle ville imperiali (Villa Arianna e Villa San lvlarco) per avere una descrizione dettagliata delle tecniche e dei materiali impiegati nelle pitture murali dei vari ambienti. Sono stati anche programmati controlli sul degrado dei materialj pittorici. Di concerto con archeologi e restauratori presenti sul sito, consapevoli delle operazioni di restauro attuate nel passato e tenendo conto dell'effetto degli eventi drammatici del 79 d.C., si è cercato di capire la situazione conservativa delle pitture per fornire indicazioni sulle operazioni di restauro. Nel corso delle missioni si sono osservate mediante microscopio digitale le superfici pittoriche divari ambienti e si sono effettuati dei microprelievi in posizioni marginali e rappresentative delle cromie presenti. Successivamente i campioni sono stati sottoposti ad analisi presso i laboratori universitari, ad analisi con varie tecniche analitiche e spettroscopìche di tipo atomico e molecolare, come la fluorescenza di raggi X (XRF). la spettroscopia FT-lR in trasmissione e in riflessione, la microscopia Raman con laser rosso e verde.
Una considerevole massa di dati ottenuta con i vari tipi di analisi permette di tracciare una sinossi delle tavolozze pittoriche degli artisti al lavoro, dello stato di conservazione dello strato pittorico, del degrado di alcuni dei pigmenti utilizzati in antico, e della presenza di materiali impiegati per il restauro nel corso dei decenni. Sono state evidenziate opere di mani differenti, in base all'impiego di tonalità realizzate con miscele di pigmenti e con sovrapposizione di materiali diversì. ln alcune aree il cinabro risulta virato in nero con produzione di solfocloruri di mercurio. Le decorazioni a mezzo fresco risultano spesso alterate e soggette a caduta di parti dello strato pittorico.
2017
- Process Intensification by Experimental Design Application to Microwave-Assisted Extraction of Phenolic Compounds from Juglans regia L.
[Articolo su rivista]
Rosa, Roberto; Tassi, Lorenzo; Orteca, Giulia; Saladini, Monica; Villa, Carla; Veronesi, Paolo; Leonelli, Cristina; Ferrari, Erika
abstract
Microwave-assisted extraction was applied to Juglans regia L. fresh male flowers and unripe walnut seeds to evaluate the total phenolic contents of the extracts as well as the percentage of water-soluble polyphenols. The research was planned using the Design of Experiments technique to investigate the role on the extraction efficiency of different parameters, such as temperature, time and number of microwave heating cycles, together with their possible interactions. Optimization was achieved by applying a Response Surface Methodology comprising a three-factor, two-level, full-factorial Face-Centred Central Composite Design. The two input variables with a significant effect on the recovery of phenols from fresh male flowers were the extraction temperature and the number of microwave cycles. In the case of unripe walnut seeds, a linear two-factor interaction model was selected, with significant interactions occurring between temperature and time, and time and number of microwave cycles. The best experimental conditions were as follows: 100 °C, 6 min, three microwave heating cycles and 22.7 ± 0.2 mg gallic acid equivalent (GAE)/g (total phenolic content, PC); energy consumption calculations suggested slightly different conditions: 60 °C, 30 min, three microwave heating cycles and 20.7 ± 0.3 mg GAE/g (TPC).
2017
- Produzioni castanicole e identità territoriale: parliamone!
[Capitolo/Saggio]
Durante, Caterina; Ferrari, Erika; Foca, Giorgia; Benvenuti, Stefania; Tassi, Lorenzo
abstract
Il capitolo del volume tratta, in forma divulgativa, il problema della tracciabilità merceologica di alcune varietà castanicole della provincia di Modena. La caratterizzazione chimico-analitica effettuata su diversi campioni rappresentativi di altrettante cultivar geograficamente localizzate, consente la eventuale discriminazione delle varietà medesime. Il volume editato da Artestampa, appartiene ad una Collana che si sviluppa nel tempo, con l'obiettivo di far conoscere, descrivere e rappresentare alcune eccellenze agroalimentari e produzioni specifiche dei territori modenesi.
2016
- Hexavalent chromium and some trace metals in concrete from buildings of different ages in northern Italy
[Articolo su rivista]
Costeri, Eric; Martinelli, Giovanni; Sighinolfi, Giampaolo; Tassi, Lorenzo; Zannini, Paolo
abstract
The content of total hexavalent chromium (CrVI), total chromium (Cr) and other metals (Fe, Mn, Ni and Co) was determined in the cement matrix of concrete present in samples collected in both old and recent buildings located in the town of Modena (northern Italy). The cement matrix of concrete was obtained by eliminating the aggregate components by means of disaggregation and was ground until it could pass through a 63-μm-sieve. In addition, samples of bagged commercial cements were considered. Metal determination was obtained by inductively coupled plasma optical emission spectroscopy after strong acid dissolution (HCl–HNO3). Total Cr(VI) determination was obtained after mild acid attack (HCl) and analysed by UV–Vis spectrophotometry. Analytical data values obtained indicate that the highest concentrations of metals were found in concrete and in bagged cement samples characterized by high Fe concentration. High Cr(VI) concentrations both in the cement matrix of concrete and in cement samples were found in total Cr-rich samples. Cr(VI) concentrations were about 20–30% of total Cr. The data obtained indicate that secondary raw materials and industrial by-product powders utilized in the modern cement industry may significantly increase Cr(VI) in concrete.
2015
- Application of strontium isotopic analysis to the promotion of the Vignola sweet cherry PGI
[Relazione in Atti di Convegno]
Berni, Alex; Baschieri, Carlo; Bertacchini, Lucia; Durante, Caterina; Marchetti, Andrea; Tassi, Lorenzo
abstract
The perceived quality of a food commodity may critically depend on the food origin, when regional traditions about the same food production are well-known [1]. This is certainly the case of Vignola Sweet Cherry, which is covered by the Protected Geographical Indication (PGI). The development of a territoriality model for Vignola Sweet Cherry PGI by means of analytical indicators hence represent a very intriguing task, useful for the promotion of the product itself.
In the framework of the pilot project “Ciliegia-UNIMORE2014”, we have assessed the effectiveness of the isotope ratio 87Sr/86Sr as direct traceability indicator, since this indicator have already provided excellent results in similar studies. [2].
Thanks to the collaboration of single producers and to the Association of sweet cherry, plum and typical fruit of Vignola, we have monitored the 87Sr/86Sr ratio in soils, branches and sweet cherry fruits of 3 producing fields, as well as in 100 fruit samples belonging to 20 different cultivars and coming from ten municipalities of the region of production. For a more complete characterization of the cherries, the concentration of 10 metals (major and trace constituents) and the polyphenols content have been determined.
2014
- Processo per l’estrazione e purificazione di frazioni polifenoliche da prodotti secondari delle lavorazioni agro-alimentari zuccheriere
[Brevetto]
Martinelli, Aldo; Tassi, Lorenzo; Vignali, Moris
abstract
La presente invenzione riguarda un metodo per la preparazione di estratti di tannini da semilavorati, prodotti secondari e/o prodotti di scarto derivanti dalle lavorazioni dell’industria zuccheriera, in particolare dal melasso e/o borlande ottenute dalla lavorazione dello zucchero. Il metodo comprende un passaggio di diluizione di un semilavorato, un prodotto secondario e/o un prodotto di scarto delle lavorazioni agroalimentari zuccheriere, con un solvente organico e/o una soluzione acquosa acida, e successivi step di purificazione della miscela diluita mediante filtrazione e mediante cromatografia su colonna di materiali adsorbenti, a base silicea, o su resine e polimeri aromatici macromolecolari per uso alimentare. La frazione tanninica trattenuta sulla colonna cromatografica è successivamente eluita, almeno una volta, con un solvente organico, a dare un estratto polifenolico.
2013
- ENHANCING CONSUMER QUALITY PERCEPTION TOWARDS PROTECTED DESIGNATION OF ORIGIN PRODUCTS BY GEOGRAPHICAL TRACEABILITY: THE CASE OF BOLOGNA POTATOES PDO
[Abstract in Atti di Convegno]
Bertacchini, Lucia; Durante, Caterina; Marchetti, Andrea; Silvestri, Michele; Tassi, Lorenzo
abstract
The development of analytical methodologies able to confirm/determinate the geographic origin of food is becoming an increasingly dynamic area in authenticity as well as traceability context.
The globalization of agri-food system led to the spread of different varieties of food and raw materials around the world but sometimes also to a loss in their quality. Therefore, geographical origin of food often became synonymous of quality and safety and its authentication remains an important goal for producers and consumers too.
Aim of this study is to develop a geographical traceability model for a typical food of Bologna district, namely the Bologna PDO potatoes. The product obtained the designation of origin in 2009 and according to the respective European Regulation [1], its production can be obtained from a variety, ‘Primura’, grown in soils of Bologna district. In particular, in this study, among the different geographical indicators, strontium isotopic ratio, 87Sr/86Sr, has been used, given to its tracer potentialities able to link a food to its territory of origin [2]. Thanks to the collaboration with the Consortium of the potato producers of Emilia Romagna (ASSOPA), within a project funded by Emilia Romagna region [3], samples of potato tubers of two varieties (‘Agata’ and ‘Primura’), harvested in 2012, and soils (0–20 cm depht) were collected in different cultivated areas of Emilia Romagna. In particular, three different geological substrates soils were considered: "Alluvional Plain of the Appennine Rivers" (Bologna, Ravenna), "Po Plain" and "Coastal Plain" (Ferrara). All sampling sites were chosen on the basis of productivity and availability of the farmer criteria.
87Sr/86Sr values in potatoes and soils samples have been determined by using a double focusing magnetic sector multicollector. The isotopic values obtained for potatoes perfectly matched with their respective soils in almost all the cases. Furthermore, the used indicator was able to discriminate samples coming from lowlands and the Emilia Romagna’s coast. Nevertheless, more work is needed, such as the careful understanding of the impact of agricultural practices (e.g. conditions of use of fertilizers and of irrigation water) and the validation of model with the analysis of samples coming outside the Bologna district.
2013
- Mercury isotope ratios as contamination markers: procedure development and applications
[Abstract in Atti di Convegno]
Berni, Alex; Baschieri, Carlo; Durante, Caterina; Marchetti, Andrea; Bertacchini, Lucia; Covelli, Stefano; Petrini, Riccardo; Tassi, Lorenzo; Emili, Andrea; Manzini, Daniela
abstract
Mercury, Hg, is one of the most harmful elements present in the Earth, and has both natural and
anthropological sources. Moreover, Hg undergoes many different transformation pathways during
its biogeochemical, or industrial, cycles which in general involve redox reactions, both abiotic and
biotic, and phase changes. Despite the toxicity of this pollutant, there is still a lack in the
knowledge about its biogeochemistry in the ecosystem and, therefore, it is of utmost relevance to
develop new scientific approaches to deepen its transformation mechanisms and to identify the
contamination sources. In this context, the determination of mercury stable isotopes ratios seems to
be an extremely interesting and challenging application to verify the “provenance” of the element,
i.e. to identify whether it is of natural or anthropogenic source. This approach can be useful in case
of polluted areas where many are the contamination sources in order to plan an environmental
requalification, as in the present case study represented by the National Interest Site of the lagoon of
Marano-Grado (Trieste, Italy), which is the main object of the present investigation.
2012
- MERCURY ISOTOPE RATIOS AS CONTAMINATION MARKERS:
PROCEDURE DEVELOPMENT AND APPLICATIONS
[Abstract in Rivista]
Baschieri, Carlo; Durante, Caterina; Marchetti, Andrea; Berni, Alex; Bertacchini, Lucia; Stefanocovelli, ; Petrini, Riccardo; Emili, Andrea; Tassi, Lorenzo
abstract
Mercury is one of the most harmful elements present in the Earth, and has
both natural and anthropological sources. Moreover, Hg can undergo to
many different transformation pathways during its biogeochemical, or
industrial, cycles which in general involve redox reaction, both abiotic and
biotic, and phase changes (1). Despite the toxicity of this pollutant, there is
still a lack in the knowledge about the biogeochemistry of mercury in the
ecosystem and, therefore, it is of utmost relevance to develop new scientific
approaches to understand its transformation mechanisms and to identify its
contamination sources. In this context, the determination of mercury stable
isotopes ratios and, in particular, the identification of fractionation processes
seems to be an extremely interesting and challenging application to verify
the “provenance” of the element. Mercury, in fact, undergoes to both mass
dependant, MDF, and mass independent fractionation, MIF, processes. In
particular the MIF, involving only the odd isotopes (199Hg and 201Hg),
appears to be a characteristic fingerprint of the process and the pathways
involved in the Hg transformations (2). Thus, the study of both fractionation
phenomena can be a powerful tool to identify its natural or anthropogenic
source. This approach can be useful in case of polluted areas where many
are the contamination sources in order to plan an environmental
requalification. An intriguing case study is represented from the National
Interest Site of the lagoon of Marano-Grado (Trieste, Italy), which is object
of the present study. For these purposes, the evaluation of the isotopic
composition in samples coming from this area has been performed by means
of an HR-MC-ICP/MS system for the simultaneous determination of all the
isotopes of interest (3). Due to the difficulties of the mercury ICP
determination and the high number of the acquisition parameters the
optimization and the validation of the analytical procedure was required, in
order to obtain highly accurate and precise data. After this first step the
method has been applied for the determination of the Hg isotopic
fingerprints in environmental samples (e.g. sediments) coming from the
Marano-Grado area.
(1) W. Fitzgerald, C. Lamborg, Treatise on Geochemistry 9, Elsevier, 2004.
(2) B. Bergquist, J. Blum, Elements, (2010), 353-357.
(3) D. Foucher, H. Hintelmann, Anal. Bioanal. Chem., (2006), 1470-1478.
2012
- Recupero di principi bioattivi da prodotti secondari di lavorazioni agro-alimentari
[Brevetto]
Martinelli, A.; Tassi, Lorenzo; Vignali, M.
abstract
La presente invenzione riguarda un metodo per la preparazione, mediante frazionamento sequenziale, di almeno 3 frazioni costituite da: estratti di tannini, miscele di acidi organici e miscele di composti zuccherini, a partire da semilavorati, prodotti secondari e/o prodotti di scarto derivanti dai processi produttivi dell’industria di trasformazione della frutta secca o disidratata, in particolare dalle soluzioni di cottura e dai liquidi reflui di ricondizionamento idrico dei frutti delle Rosaceae, e/o dalle borlande zuccherine ottenute in un qualunque stadio del processo menzionato.
2011
- Adulteration of the anthocyanin content of red wines: perspectives for authentication by FT-NIR and 1H NMR spectroscopies
[Articolo su rivista]
Ferrari, Erika; Foca, Giorgia; M., Vignali; Tassi, Lorenzo; Ulrici, Alessandro
abstract
In the Italian oenological industry, the regular practice used to naturally increase the colour of red wines consists in blending them with a wine very rich in anthocyanins, namely Rossissimo. In the Asian market, on the other hand, anthocyanins extracted by black rice are frequently used as correctors for wine colour. This practice does not produce negative effects on health; however, in many countries, it is considered as a food adulteration. The present study is therefore aimed to discriminate wines containing anthocyanins originated from black rice and grapevine by using reliable spectroscopic techniques requiring minimum sample preparation. Two series of samples have been prepared from five original wines, that were added with different amounts of Rossissimo or of black rice anthocyanins solution, until the desired Colour Index was reached. The samples have been analysed by FT-NIR and 1H NMR spectroscopies and the resulting spectra matrices were subjected to multivariate classification. Initially, PLS-DA was used as classification method, then also variable selection/classification methods were applied, i.e. iPLS-DA and WILMA-D. The classification with variable selection of NIR spectra permitted to classify the test set samples with an efficiency of about 70%. Probably these not excellent performances are due to the matrix effect, together with the lack of sensitivity of NIR with respect to minor compounds. On the contrary, very satisfactory results were obtained on NMR spectra in the aromatic region between 6.5÷9.5 ppm. The classification method based on wavelet-based variables selection, permitted to reach an efficiency in validation greater than 95%. Finally, 2D correlation analysis was applied to FT-NIR and 1H NMR matrices, in order to recognise the spectral zones bringing the same chemical information.
2011
- Modelling of Experimental Thermophysical Data by Mixing of a Ternary Solvent System
[Capitolo/Saggio]
Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Thermomechanic and thermodynamic properties of mixing solvents in the liquid state have proven a powerful tool in elucidating the specific interactions and structural features supporting the liquid structure in multicomponent nonelectrolytic solutions. Mass transport properties (density, viscosity), thermophysical properties (relative permittivity, refractive index), and related thermodynamics can deepen elucidate the solvent – solvent specific interactions and behavioural peculiarities of the complex real systems. In this paper, we will primarily deal with the experimental measurements and correlative studies both on temperature and composition, of the above mentioned properties (Y), working with a ternary solvent system containing 1,2-ethanediol (ED), 2-methoxyethanol (ME) and 1,2-dimethoxyethane (DME), at various temperatures in the range -10 £ t (°C) £ 80, and with different compositions covering the whole miscibility field of the selected species. These components are strictly parent species, all being 1,2-ethanedyil-derivatives (-CH2-CH2-), pertaining to the amphiphile class molecules, with different balancing degree of hydrophobic and hydrophilic properties. Furthermore, the excess properties (YE) and deviation functions (DY) are largely stressed and examined along the text in order to identify the presence of solvent – cosolvent adducts in these ternary mixtures.
2011
- Optimization of microwave assisted digestion procedure by means of chemometric tools
[Capitolo/Saggio]
Cocchi, Marina; Durante, Caterina; Marchetti, Andrea; LI VIGNI, Mario; Baschieri, Carlo; Bertacchini, Lucia; Sighinolfi, Simona; Tassi, Lorenzo; S., Totaro
abstract
The introduction of microwave (MW) heating devices inthe “chemical laboratory” represents one of the most important andrelevant application that contributes to speed up the “samplepreparation” step and, therefore, dramatically reduces the timeneeded for the analytical response. On the other hand, few andgeneric are the criteria developed to compare analytical dataobtained with conventional sample preparation approach withrespect to the MW one. In fact, when reference materials, RMs, arenot available, or not sufficiently representative of the real matrixunder investigation, it is often difficult to know when the sampledisgregation has come to completeness or if it is still possible tosave more time on the MW heating process. This contribute willdeal with the use of the more innovative Design of Experimentstools to the MW assisted digestion of organic rich matrices focusing on the potentialities of these experimental approaches when developing new disgregation analytical methods. The experimental approach concerns in finding the “optimum process conditions” in terms of solvent reaction mixture and recovery metal content.
2011
- Seeds of Horse Chestnut (Aesculus hippocastanum L.) and Their Possible Utilization for Human Consumption
[Capitolo/Saggio]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina; Durante, Caterina; LI VIGNI, Mario; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo
abstract
This chapter appraises the seeds of horse chestnuts (. Aesculus hippocastanum [AH]) and their derived products. Escin, the major bioactive principle in AH seeds, has shown satisfactory evidence of clinically significant activity in the treatment of chronic venous insufficiency, hemorrhoids, postoperative edema, and mammary induration. There is some evidence that various escin molecules, such as saponins and sapogenins, show beneficial effects when administered at the right concentration, exhibiting an ethanol absorption inhibitory effect and hypoglycemic activity in the oral glucose tolerance test in vivo. Horse chestnut extract has a higher antioxidant activity than vitamin E, showing one of the highest "active-oxygen" scavenging abilities compared to other natural products. β-Escin from AH extracts was also tested to evaluate the chemopreventive efficacy of its dietary intake on azoxymethane-induced colonic aberrant crypt foci. The main adverse effects of escins in humans are due to their hemolytic activity. Research efforts in this field are devoted to improving the selectivity for aberrant red corpuscles, promoting the β-escin fraction as a useful candidate agent for exploring new potential antileukemic drugs. Fresh or naturally desiccated seeds are usually treated by long leaching with water or wooden ashes to remove harshness and bitterness. These treatments cause a variation in the molecular structures of escin fractions, reducing the toxicity but maintaining their nutraceutical potential and anti-obesity effects. Alternatively, the slow roasting of nuts makes the escins harmless and the seeds edible. The claimed toxicity of these extracts makes them natural antibacterials, antimicrobials, antivirals, and antifungals, to some extent, that also act as environmentally biocompatible phytotherapeutics.
2009
- An investigation on the palette and techniques of some high medieval codices by Raman microscopy
[Articolo su rivista]
Baraldi, Pietro; Moscardi, Giulia; P., Bensi; M., Aceto; Tassi, Lorenzo
abstract
a non-desctructive investigation of inks and pigments used in late antiquity and in medievasl codices. Inks from Pompeii and codices have been compared. A change in the use of pigments is observable between the 9th and the 12th centuries in the production of the scriptorium of Nonantola.
2009
- Classification of NMR spectra collected on wines added with anthocyanins from grape and black rice
[Relazione in Atti di Convegno]
Foca, Giorgia; Ferrari, Erika; M., Vignali; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2009
- Produzione di tannini di alta qualità e polifenoli associati, estratti da essenze di noce, destinati ad applicazioni speciali (campo agroalimentare, nutraceutico, cosmetico-farmacologico) e tradizionali (settore tintorio, tessile, conciario, edilizio)
[Brevetto]
A., Martinelli; Tassi, Lorenzo; M., Vignali
abstract
L’invenzione si riferisce a processi di:-precondizionamento delle materie prime,-estrazione (dalle materie prime), -produzione (mediante utilizzo di tecnologie adatte), -purificazione (mediante utilizzo di tecnologie adatte), ed -applicazione (su processi e prodotti di filiere diverse) di Tannini di Alta Qualità e polifenoli associati (TAQ), ottenibili da vari distretti vegetativi di essenze di noce (TAQ di NOCE). Questi Tannini sono fortemente aromatici, si presentano in forma polverulenta, pastosa e liquida (in funzione della specie varietale e del distretto vegetativo - essenza - di provenienza), hanno caratteristiche di grado alimentare, sono destinati ad applicazioni come ingredienti di formulazione in campo agroalimentare (ed altri settori merceologici compatibili con l’uso dei tannini). Attualmente, non esistono in commercio prodotti e materiali analoghi, che si possano configurare come i “TAQ di NOCE” proposti in questo brevetto.
2008
- Caratterizzazione di vini addizionati di antociani di diversa origine mediante spettroscopia NIR e analisi chemiometrica dei segnali
[Abstract in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Tassi, Lorenzo; Vignali, M.
abstract
-
2008
- Classificazione multivariata di spettri NIR di vini addizionati di antociani provenienti da uva e da riso nero
[Abstract in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Tassi, Lorenzo; Vignali, M.
abstract
-
2008
- Investigation on Palette and Techniques of Some High Middle-age Codices by Raman Microscopy
[Abstract in Atti di Convegno]
Baraldi, Pietro; Moscardi, Giulia; Bensi, Paolo; Aceto, Maurizio; Tassi, Lorenzo
abstract
to be published in E-PRESERVATION SCIENCE, http//www.E-PRESERVATIONSCIENCE.ORG
2008
- Metodi rapidi di valutazione qualitativa del frumento tenero
[Articolo su rivista]
Foca, Giorgia; Ulrici, Alessandro; M., Corbellini; R., Caramanico; M., Lucisano; M. A., Pagani; Cocchi, Marina; Tassi, Lorenzo; G., Boggini
abstract
SommarioNella classificazione di frumenti teneri mediante il metodo ISQ (Indice Sintetico di Qualità), un valutatore esperto classifica ogni campione di grano in diverse categorie qualitative, definite in base ad alcuni parametri chimici e reologici. Le analisi impiegate per la determinazione di tali parametri richiedono lunghi tempi di esecuzione e l’impiego di personale esperto, mentre durante le transazioni commerciali i prodotti devono essere caratterizzati in tempi molto brevi. Per questa ragione, è stato sviluppato un metodo veloce ed automatizzato per la classificazione del frumento, basato sull’accoppiamento della spettroscopia nel vicino infrarosso (NIR) con metodi di analisi multivariata dei dati.SummaryDuring the classification of bread wheats by means of the ISQ method (Synthetic Index of Quality), an expert assessor classifies each wheat sample in different quality categories, defined on the basis of some chemical and rheological parameters. The analyses involved in the determination of such parameters require long times of execution and the employing of skilled personnel, whereas, during the commercial transactions, the products need to be characterized in very short times. For this reason, we developed a fast and automated method of wheat classification based on the coupling of the Near InfraRed spectroscopy (NIR) and multivariate data analysis methods.
2008
- Modelling of Experimental Thermophysical Data by Mixing of a Ternary Solvent System, in Solution Chemistry
[Capitolo/Saggio]
Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Thermomechanic and thermodynamic properties of mixing solvents in the liquid state have proven a powerful tool in elucidating the specific interactions and structural features supporting the liquid structure in multicomponent nonelectrolytic solutions. Mass transport properties (density, viscosity), thermophysical properties (relative permittivity, refractive index), and related thermodynamics can deepen elucidate the solvent – solvent specific interactions and behavioural peculiarities of the complex real systems. In this paper, we will primarily deal with the experimental measurements and correlative studies both on temperature and composition, of the above mentioned properties (Y), working with a ternary solvent system containing 1,2-ethanediol (ED), 2-methoxyethanol (ME) and 1,2-dimethoxyethane (DME), at various temperatures in the range -10 £ t (°C) £ 80, and with different compositions covering the whole miscibility field of the selected species. These components are strictly parent species, all being 1,2-ethanedyil-derivatives (-CH2-CH2-), pertaining to the amphiphile class molecules, with different balancing degree of hydrophobic and hydrophilic properties. Furthermore, the excess properties (YE) and deviation functions (DY) are largely stressed and examined along the text in order to identify the presence of solvent – cosolvent adducts in these ternary mixtures.
2008
- Multivariate analysis of analytical signals to decipher relevant chemical information
[Capitolo/Saggio]
Ulrici, Alessandro; Cocchi, Marina; Durante, Caterina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo
abstract
Two main elements have recently characterized the research in the analytical field: on one hand the huge development of instrumental analysis in the direction of hyphenated techniques and, on the other hand, the huge development and decreasing cost of computers together with the increased capacity of computational tools. Moreover, new issues are presented to the analytical researcher by new regulations that impose to demonstrate that the whole process is under control, e.g. in the industrial/productive context, or in the life science context by the emerging need of systems biology. Thus, the role of chemometrics is more and more increasing and the toolbox of chemometrics-like methods has been progressively enriched.In particular, deciphering signal-fingerprinting of complex matrix samples requires a deeper consideration on the nature of signals feature, and it has to be taken into account that the information pertinent to the problem is mixed with many uninformative sources of variations that may affect part or the whole signal domain. These issues from the data analysis point of view are reflected in a greater complexity of the preprocessing/pretreatment and variable selection steps.The main focus of this chapter will be on feature selection methodology; after a concise review of the main recently proposed feature selection methods, the specific case of feature selection in the wavelet (WT) domain will then be considered. In particular, it will deal with illustration of our recent developed tools for WT-feature selection in regression and classification tasks. The discussion of different applications will be the core of the work, to illustrate the effectiveness of the integration of both basic (simple) and more advanced methodologies together, with a complete strategy embracing data exploration, modelling, data display-interpretation and validation.
2008
- Preface [New trends in analytical, environmental and cultural heritage chemistry]
[Capitolo/Saggio]
Tassi, Lorenzo; Colombini, Maria Perla
abstract
This volume is intended to provide a general overview of principles and practical applications of various areas of analytical chemistry, in particular (but not exclusively) in the contexts of environmental and cultural heritage conservation.
2007
- A micro-Raman archaeometric approach to Roman wall paintings
[Articolo su rivista]
Baraldi, Pietro; Baraldi, Cecilia; R., Curina; Tassi, Lorenzo; Zannini, Paolo
abstract
Infrared and Raman spectra have been recorded on the surface of plasters from Regium Lepidi (Reggio Emilia, Italy). A palette has been identified, that can be compared with the ones from the nearby towns of the Roman Empire, but some peculiarities can be outlined. Some of the pigments could come from the territory, even though the techniques could be ascribed to those usually present in the 1st century a.c.
2007
- Caratterizzazione del Nocino tipico emiliano mediante indagini chimico-fisiche ed analisi chemiometriche
[Relazione in Atti di Convegno]
Foca, Giorgia; Franchini, Giancarlo; Grandi, Margherita; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2007
- Chemical composition and characterisation of seeds from two varieties (pure and hybrid) of Aesculus hippocastanum
[Articolo su rivista]
Baraldi, Cecilia; Bodecchi, Lidia Maria; Cocchi, Marina; Durante, Caterina; Ferrari, Giorgia; Foca, Giorgia; Grandi, Margherita; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Investigations have been conducted on some samples of naturally desiccated horse-chestnuts (Aesculus hippocastanum), representativeof the two most common mediterranean varieties: the pure species (AHP, giving white flowers), and a hybrid (AHH, giving pink flowers).Different experimental techniques have been used to gain more information on morphological structure and chemical composition ofthese complex matrices. Surface analysis by SEM showed no differences in such floured samples (wild type), while thermal behaviour(DSC) outlines some significant differences between them. Chemical composition reveals some differences in residual moisture(AHP = 6.97%; AHH = 6.59%), proteins (AHP = 2.64%; AHH = 1.82%), lipids (AHP = 4.13%; AHH = 5.10%), glucides (AHP =15.2%; AHH = 14.3%), and ashes (AHP = 2.51%; AHH = 2.19%). Most likely, these characters modulate other undifferentiated chemicalparameters, such as cold water solubility (CWS:AHP = 53.9%; AHH = 48.6%), and total inorganic soluble salts (TISS:AHP = 2.18%; AHH = 1.92%). Principal component analysis was applied to differentiate the two horse-chestnuts varieties. In particular,the first principal component effectively distinguish and discriminates AHH and AHP samples in two well-separated categories, giving, atthe same time, some information on the influence of the whole set of chemical compositional parameters.
2007
- Determinazione di acidi e zuccheri presenti negli impasti per la produzione industriale di pane a diversi stadi della lavorazione
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; LI VIGNI, Mario; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2007
- End-use classification of wheat flours after feature selection on NIR spectra
[Relazione in Atti di Convegno]
Foca, Giorgia; Ulrici, Alessandro; Cocchi, Marina; Corbellini, M; Tassi, Lorenzo
abstract
-
2007
- Reproducibility of the Italian ISQ method for quality classification of bread wheats: An evaluation by expert assessors
[Articolo su rivista]
Foca, Giorgia; Ulrici, Alessandro; M., Corbellini; Ma, Pagani; M., Lucisano; Franchini, Giancarlo; Tassi, Lorenzo
abstract
The great variety of different bakery products in Italy has led to the development of a method, the Synthetic Index of Quality (Indice Sintetico, di Qualita, ISQ), for the classification of bread wheats in different quality categories. Based on chemical and rheological properties, each wheat sample is assigned to the most suitable class by an expert assessor. In many cases this procedure is not straightforward, making the class assignation uncertain, thus leading to the possibility of controversies during the trading phase. In the present study, in order to have a quantitative estimate of the validity and reliability of this procedure, a panel composed of nine expert assessors was utilised for the repeated evaluation of 100 samples of bread wheats of various qualities. The results suggest that the proposed approach can be used both to monitor the reliability of the single assessors, and to identify samples whose class assignation is reasonably indubitable, e.g. to be used for the development of automated classification methods. Moreover, the analysis of the most uncertain assignation cases can be useful in order to enhance the ISQ classification method itself. (c) 2007 Society of Chemical Industry.
2006
- Classificazione multivariata sulla base di spettri NIR dei risultati di un panel test per il riconoscimento della classe qualitativa del grano tenero
[Relazione in Atti di Convegno]
Ulrici, Alessandro; Foca, Giorgia; Cocchi, Marina; Corbellini, M; Franchini, Giancarlo; Tassi, Lorenzo
abstract
-
2006
- Durum wheat adulteration detection by NIR spectroscopy multivariate calibration
[Articolo su rivista]
Cocchi, Marina; Durante, Caterina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
In the present work, we explored the possibility of using near-infrared spectroscopy in order to quantify the degree of adulteration of durum wheat flour with common bread wheat flour. The multivariate calibration techniques adopted to this aim were PLS and a wavelet-based calibration algorithm, recently developed by some of us, called WILMA. Both techniques provided satisfactory results, the percentage of adulterant present in the samples being quantified with an uncertainty lower than that associated to the Italian official method. In particular the WILMA algorithm, by performing feature selection, allowed the signal pretreatment to be avoided and obtaining more parsimonious models.
2006
- Investigation on a Roman copper alloy artefact from Pompeii (Italy)
[Articolo su rivista]
Baraldi, Pietro; Baraldi, Cecilia; Ferrari, Giorgia; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo
abstract
A selection of samples, obtained from a particular copper-alloy domestic artefact of Roman style from Pompeii, has been analysed by using different techniques (IR, Raman, SEM-EDX, FAAS), in order to investigate the chemical nature and composition of the metals utilised for such manufacturing pieces. The surface analysis of the bright red metallic microfragments conducted by different analytical techniques, emphasises the presence of pure unalloyed copper and confirms the absence of other metallic species on the upper layers. On the contrary, the mapping analysis of the section of the laminar metal of the investigated sample shows a consistent enrichment in tin content. Finally, destructive analysis by FAAS confirms that the artefact looks like a bronze metal alloy, with a medium Sn content of about 6.5%
2006
- Study of the dependence on temperature and composition of the volumic properties of ethane-1,2-diol+2-methoxyethanol+1,2-dimethoxyethane plus water solvent system and graphical representation in the quaternary domain
[Articolo su rivista]
Ulrici, Alessandro; Cocchi, Marina; Foca, Giorgia; M., Manfredini; Marchetti, Andrea; D., Manzini; Tassi, Lorenzo; S., Sighinolfi
abstract
In this paper, the temperature and composition dependencies of the volumetric behavior are studied for the ethane-1,2-diol + 2-methoxyethanol + 1,2-dimethoxyethane + water quaternary system. Density data were collected at different temperatures ranging from -10 to 80 degrees C and at atmospheric pressure over the whole composition range, 0 :5 x(i)(i = 1, 2, 3,4) <= 1. Moreover, we also made use of the results on the six binary (ij) and four ternary (kij) subsystems studied previously. The excess molar volume (V-E) data have been fitted to an equation derived from the well-known Redlich-Kister equation and some interesting correlations were found. Furthermore, in order to represent in an effective way the behavior of the V-E = V-E(x(i)) function (and of the derived partial molar quantities) in the quaternary domain, a new algorithm has been developed, which gives 3D plots where the dependent function is depicted by means of '' colored slices '' of the tetrahedron corresponding to the investigated composition quaternary domain.
2006
- VIBRATIONAL SPECTRA OF SOME PIGMENTS FROM POMPEII
[Articolo su rivista]
Baraldi, Pietro; C., Fagnano; A., LOSCHI GHITTONI; Tassi, Lorenzo; Zannini, Paolo
abstract
Some powder pigments found in bowls in the ruins of Pompeii were investigated. Their chemical and mineralogical compositions were obtained by using FT-IR spectroscopy, Raman microscopy, X-Ray diffraction and DSC. With FTIR spectroscopy and X-Ray diffraction the main components were ascertained and the pigments attributed to Plinius' names as far as possible. With Raman microscopy a detailed examination of minor components was carried out, thereby enabling some considerations on the pigment preparation techniques to be traced. Two unusual pigments were identified, namely jarosite and buntite, already detected in wall painting and ceramics elsewhere.
2005
- Classification of bread wheat flours in different quality categories by a wavelet-based feature selection/classification algorithm on NIR spectra
[Articolo su rivista]
Cocchi, Marina; M., Corbellini; Foca, Giorgia; M., Lucisano; Ma, Pagani; Tassi, Lorenzo; Ulrici, Alessandro
abstract
In the Italian context, bread wheat flour is commercially classified in different quality categories on the basis of a Synthetic Index of Quality (Indice Sintetico di Qualit, ISQ), which is defined by means of specific parameters, i.e., hectolitric weight, falling number, protein content, alveographic indexes (W, P/L) and farinograph stability. The analyses involved in the determination of these parameters are expensive, time consuming and require specialized personnel, thus there is concern to develop alternative methods to be applied during the commercial transactions, when the products need to be characterized in very short times. For this reason, a fast technique such as an automated classification on the basis of NIR spectra acquired on the wheat flour samples could be a very useful tool. In this work, various wheat flour samples belonging to four different ISQ classes have been analysed by means of NIR spectroscopy, and the obtained spectra have been classified both by SIMCA applied to the signals subjected to different pretreatment methods, and by using a wavelet-based feature selection/classification algorithm, called WPTER. Due to the high overlap of the two intermediate quality classes, it was not possible to classify all the data set signals. However, when considering only the two extreme categories, an acceptable degree of class separation can be gained after feature selection by WPTER. Moreover, this approach allowed us to locate the NIR spectral regions that are mainly involved in the assignment of the wheat flour samples to these two quality categories.
2005
- Materiali pittorici e pigmenti
[Relazione in Atti di Convegno]
Baraldi, Pietro; Bonazzi, A.; Fagnano, C.; Tassi, Lorenzo; Zannini, Paolo
abstract
Le pitture di Pompei e le indagini scientifiche sui materiali e le tecniche, con i rinvenimenti più comuni e più insoliti
2005
- Use of multivariate analysis of MIR spectra to study bread staling
[Articolo su rivista]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Different kinds of bread, stored at constant temperature and at controlled humidity conditions for a week since their manufacturing date, were analysed by Attenuated Total Reflectance-Fourier Transform InfraRed (ATR-FTIR) spectroscopy. The collected spectra were processed by Principal Component Analysis (PCA), in order to evaluate the changes occurring during bread ageing. For the sake of comparison, the 1060-950 cm(-1) spectral window has been also investigated by curve-fitting methods. It was observed that the first PC increases monotonically with ageing of samples. Furthermore, the more influential variables on PCl correspond to spectral regions where are located stretching and bending bands, which are mainly attributed to typical starch bonds vibrations.
2004
- A study of the dielectric behavior and the liquid structure of a ternary solvent system
[Articolo su rivista]
Cocchi, Marina; Franchini, Giancarlo; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; Zanardi, Chiara; Zannini, Paolo
abstract
The static dielectric constant of the {DMF(1) + ME(2) + DME(3)} ternary mixtures was measured as a function of temperature (25 less than or equal to t/degreesC less than or equal to 80) and composition, over the whole mole fraction range 0 less than or equal to x(1),x(2),x(3) less than or equal to 1. The experimental values were processed by an empirical equation accounting for the dependence epsilon = epsilon(T, phi(i)), where phi(i) is the volume fraction of the components. A comparison between calculated and experimental data shows that this fitting relationship can be effectively employed to predict epsilon values in correspondence to experimental data gaps. Starting from the experimental measurements, some derived quantities such as molar polarisation (P), and excess counterpart (P-E) were obtained. Both the excess properties, epsilon(E) and P-E, take values partly positive and partly negative under all experimental conditions. The values of the excess quantities are indicative of the presence of specific interactions among different components in the mixtures.
2004
- Analysis of the temperature and composition dependence of viscosimetric properties of 2-butanone+2-butanol solvent mixtures
[Articolo su rivista]
S., Faranda; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Zucchi, Claudia
abstract
Kinematic viscosities were measured for 2-butanone + 2-butanol binary liquid mixtures with a capillary Ubbelohde routine viscometer in the temperature range from 273.15 to 353.15 K at atmospheric pressure, and covering the whole miscibility field (0 less than or equal to x(i) less than or equal to 1). Experimental data have been correlated by means of different empirical or semiempirical relationships, such as nu = nu(T), nu = nu(x(i)), and nu = nu(T, x(i)). Viscosity deviations, Deltanu, from ideal behavior are negative at all experimental conditions, confirming that structure breaking effects prevail in the liquids. Furthermore, the thermodynamics of viscous flow and excess Gibbs energy of activation of viscous flow, G*(E), have been calculated. As an alternative and complementary approach to such investigations, the fluidity (phi) of this binary system has been analyzed by the modified-Batschinski theory. The results are discussed in terms of the specific molecular interactions between the mixture components.
2004
- Application of NIR spectroscopy multivariate calibration to the quantification of durum wheat semolina adulteration with bread wheat flour
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2004
- Applicazione della calibrazione multivariata su spettri NIR per la quantificazione dell’adulterazione di semola di grano duro con farina di grano tenero
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2004
- Applicazione dell’algoritmo WPTER su spettri NIR di farine di frumento tenero per la classificazione nelle diverse classi di qualità
[Relazione in Atti di Convegno]
Cocchi, Marina; Corbellini, M; Foca, Giorgia; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2004
- Caratterizzazione chimico-fisica di amidi di varia origine
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Franchini, Giancarlo; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2004
- Classification of cereal flours by chemometric analysis of MIR spectra
[Articolo su rivista]
Cocchi, Marina; Foca, Giorgia; M., Lucisano; Marchetti, Andrea; Ma, Pagani; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Different kinds of cereal flours submitted to various technological treatments were classified on the basis of their mid-infrared spectra by pattern recognition techniques. Classification in the wavelet domain was achieved by using the wavelet packet transform for efficient pattern recognition (WPTER) algorithm, which allowed singling out the most discriminant spectral regions. Principal component analysis (PCA) on the selected features showed an effective clustering of the analyzed flours. Satisfactory classification models were obtained both on training and test samples. Furthermore, mixtures of varying composition of the studied flours were distributed in the PCA space according to their composition.
2004
- Density measurements of the binary mixtures of 2-butanone and 2-butanol at temperatures from –10 to 80 °C
[Articolo su rivista]
S., Faranda; Foca, Giorgia; Marchetti, Andrea; Palyi, Gyula; Tassi, Lorenzo; Zucchi, Claudia
abstract
Densities of methyl-ethyl-ketone + 2-butanol were measured at temperatures between -10 and 80 degreesC, working with the pure species and nine binary mixtures. At each experimental condition, the data were correlated by means of some empirical equations and according to well-established literature models. The estimated excess molar volumes (and some related quantities) were also evaluated by applying the Redlich-Kister equation. The results related to specific intermolecular interactions have been interpreted in terms of structural and geometrical effects.
2004
- Dielectric properties in ternary mixtures of ethane-1,2-diol+1,2-dimethoxyethane + water
[Articolo su rivista]
Foca, Giorgia; Manfredini, Matteo; Manzini, Daniela; Marchetti, Andrea; Pigani, Laura; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract
The static dielectric constant (epsilon) of ethane-1,2-diol + 1,2-dimethoxyethane + water ternary mixtures was measured as a function of temperature (263.15 less than or equal to T (K) less than or equal to 353.15) and composition, over the complete mole fraction range 0 less than or equal to x(1), x(2), x(3) less than or equal to 1. The experimental values were analyzed by empirical relationships that accounted for the dependence epsilon = epsilon(T) and Y = Y(x(i)). A comparison between calculated and experimental data shows that these fitting relationships can be reliably used to predict epsilon values, along with other related properties, in areas of experimental data gaps. Starting from the experimental measurements, some derived quantities such as molar orientational polarization (P), dipolar interaction free energy (Fmu) and the relevant thermodynamic excess mixing properties (F-mu(E), (F) over bar (E)(mu,i)), were obtained. The values of the excess quantities are indicative of the presence of specific interactions between different components in the mixtures. A discussion of data in terms of the Kirkwood theory also provides information on the short-range intermolecular interactions, suggesting the formation of stable two-component adducts rather than of more complex moieties involving all three molecular species.
2003
- Applicazione dell’Algoritmo WPTER per la Classificazione di Spettri MIR di Farine Provenienti da Diversi Careali
[Relazione in Atti di Convegno]
Cocchi, M.; Foca, G.; Marchetti, Andrea; Sighinolfi, S.; Tassi, L.; Ulrici, A.
abstract
l’Algoritmo WPTER è stato utilizzato per la Classificazione di prodotti da forno ottenuti impiegando cereali diversi mediante spettri MIR i
2003
- Applicazione dell’algoritmo WPTER per la classificazione di spettri MIR di farine provenienti da diversi cereali
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2003
- Caratterizzazione chimica di un reperto bronzeo Romano
[Relazione in Atti di Convegno]
Baraldi, Pietro; Tassi, Lorenzo; A., Varone
abstract
Ed fotolito Sicignano, Pompei
2003
- Density and volume properties of the 2-chloroethanol+2-methoxyethanol+1,2-dimethoxyethane ternary solvent system at different temperatures
[Articolo su rivista]
Ferrari, Giorgia; Foca, Giorgia; M., Manfredini; Manzini, Daniela; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
The density of the 2-chloroethanol (CE) + 2-methoxyethanol (ME) + 1,2-dimethoxyethane (DME) ternary mixtures has been measured at different temperatures ranging from -10 to 80degreesC, and over the entire composition range. The experimental data have been used to check the validity of some relationships accounting for the dependence of the density on temperature and composition domains. Starting from the primary data, some derived quantities, such as excess molar volumes V-E, partial molar volumes (V) over bar (i) and partial excess molar volumes (V) over bar (E)(i), have been obtained. In these mixtures, V-E is always positive for the [CE(1) + ME(2)] binaries, while it is generally negative at all other experimental conditions, showing the greatest deviations along the binary axes corresponding to the binary subsystems in the sequence [CE(1) + DME(2)] < [CE(1) + ME(2)] < [ME(1) + DME(2)]. The results are compared and discussed to in terms of changes in molecular association and structural effects in these solvent systems.
2003
- Il sistema solvente ternario 1,2-etandiolo + 1,2-dimetossietano + acqua: proprietà dielettriche a diverse temperature
[Relazione in Atti di Convegno]
Foca, Giorgia; Franchini, Giancarlo; Manfredini, Matteo; Manzini, Daniela; Tassi, Lorenzo; Ulrici, Alessandro; Zannini, Paolo
abstract
-
2003
- Refractive properties of binary mixtures containing 1,2-dichloroethane + 2-methoxyethanol or 1,2-dimethoxyethane
[Articolo su rivista]
M., Manfredini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Refractive index (n) and related properties such as molar refraction (R) have been investigated for DCE + ME and DCE + DME binary mixtures over the entire composition range, at different temperatures in the interval 0 less than or equal to t / degreesC less than or equal to 70. Some empirical and theoretical relationships have been applied to study the dependence of the measured and derived quantities on temperature and on binary composition. Furthermore, the excess functions n(E), R-E and the excess Kirkwood correlation parameters Deltag have been examined, in order to identify the presence of solvent-cosolvent adducts in these binary solvent systems. The results obtained have been interpreted on the basis of specific intermolecular interactions between different species. (C) 2003 Elsevier Science B.V. All rights reserved.
2003
- Selective solvation of chiral compounds in binary mixtures of 2-butanone + 2-butanol
[Relazione in Atti di Convegno]
Faranda, S; Foca, Giorgia; Manfredini, Matteo; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo
abstract
-
2003
- Solvatazione selettiva di biomolecole in miscele binarie 2-butanone + 2-butanolo
[Relazione in Atti di Convegno]
Foca, Giorgia; Manfredini, Matteo; Manzini, Daniela; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Zucchi, Claudia
abstract
-
2003
- Viscosimetric properties and internal structure of N,N-dimethylformamede+1,2-dimethoxyethane binary mixtures
[Articolo su rivista]
Cocchi, Marina; M., Manfredini; D., Manzini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; Zannini, Paolo
abstract
The kinematic viscosities (v) of liquid binary mixtures of N,N-dimethylformamide and 1,2-dimethoxyethane were measured at 19 temperatures in the range -10 less than or equal to t / degreesC less than or equal to 80, employing the pure species and 9 their solutions covering the whole miscibility range expressed by the condition 0 less than or equal to x(i) less than or equal to 1. The measured values have been used to test some empirical equations of the type v=v(T), v=v(x(i)), and v=v(T,x(i)), in order to obtain useful correlation models with predictive ability in correspondence of the experimental data gaps. Starting from the experimental data, the excess kinematic viscosities (v(E)) have been calculated. Sign and magnitude of these quantities have been discussed in terms of type and nature of specific intermolecular interactions. Some derived quantities such as thermodynamic parameters of the viscous flow (DeltaG*, DeltaH* and DeltaS*), have been calculated on the basis of Eyring's model. Furthermore, the fluidity of this binary solvent system was analysed and interpreted following Hildebrand and modified-Hildebrand correlation models. (C) 2003 Elsevier Science B.V. All rights reserved.
2002
- Beta-functionalised polythiophenes as microelectrode modifiers in low conductive media
[Articolo su rivista]
Cocchi, Marina; Franchini, Giancarlo; M., Manfredini; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; Zanardi, Chiara; Zannini, Paolo
abstract
A study on polythiophene coated microelectrodes is reported, the goal being that of checking the capability of these electrochemical systems to work in low conductive media. The possibility of electrochemically p-doping the polymer in the presence of very low concentrations or even in the absence of supporting electrolyte in the solution is ascertained, opening the way to the use of similar systems in pure solvent media. This result is obtained in such conditions that the presence of residual charges - and corresponding counterions - trapped inside the film coating can be reasonably hypothesised.
2002
- Caratterizzazione di farine di frumento mediante analisi PCA di spettri infrarossi
[Articolo su rivista]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
La qualità risulta essere un criterio fondamentale per la scelta dei prodotti alimentari da parte dei consumatori, pertanto le tecniche anaitiche che si occupano del controllo della composizione chimica degli alimenti e dell'individuazione di eventuali adulterazioni sono in continuo aumento.
2002
- Classificazione di mosti varietali rossi mediante PCA applicata a cromatogrammi HPLC di antociani
[Relazione in Atti di Convegno]
Camurali, M; Foca, Giorgia; Franchini, Giancarlo; TARANTINO E., M; Tassi, Lorenzo; Vignali, M.
abstract
-
2002
- Classificazione di spettri MIR acquisiti su matrici di origine cerealicola mediante l’utilizzo dell’algoritmo WPTER
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
-
2002
- Densities and excess molar volumes of binary mixtures containing 1,2-dichloroethane + 2-methoxyethanol or 1,2-dimethoxyethane at different temperatures
[Articolo su rivista]
M., Manfredini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali
abstract
Density of the 1,2-dichloroethane + 2-methoxyethanol or 1,2-dimethoxyethane binary mixtures have been measured at different temperatures over the complete composition range. Several experimental measurements have been used to check the validity of the relationships accounting for the dependence of the density on temperature and composition, useful to obtain interpolated values in correspondence of the experimental data gaps. Starting from the primary data, some derived quantities, such as partial molar volumes, excess and partial excess molar volumes, have been obtained. In these mixtures, V-E is always positive for DCE + ME binaries, while an S-shaped dependence on composition at each temperature is obtained in DCE + DME system, showing positive values in the DCE rich-region and negative values at the opposite extreme. The results are compared and discussed to shed some light to the changes in molecular association and structural effects in these binary solvent systems.
2002
- Density, refractive index, and related properties for 2-butanone plus n-hexane binary mixtures at various temperatures
[Articolo su rivista]
Baraldi, Pietro; M. G., Giorgini; M., Manfredini; D., Manzini; Marchetti, Andrea; Tassi, Lorenzo
abstract
Density refractive index n and the related properties molar volume V and molar refraction R have been investigated for 2-butanone + n-hexane liquid binary mixtures over the entire composition range and a wide range of temperatures. Some well-known relationships have been applied to study the temperature and composition dependence of the measured and derived quantities. Furthermore, the deviations of the respective excess properties V-E, n(E), and R-E have been examined, with the aim of identifying particular intermolecular interaction patterns responsible for the macroscopic behavior of these binary mixtures. The results have been interpreted on the basis of structural and geometric effects between the components.
2002
- Il sistema ternario metanolo + etanolo + 1-propanolo: proprietà volumiche e disegno sperimentale di miscele solventi
[Relazione in Atti di Convegno]
Cocchi, Marina; Foca, Giorgia; Franchini, Giancarlo; Manfredini, Matteo; Manzini, Daniela; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Vignali, M.
abstract
-
2002
- Kinematic viscosities of binary liquid mixtures of 2-butanone with 1,2-propanediol
[Articolo su rivista]
M., Manfredini; Marchetti, Andrea; S., Sighinolfi; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; C., Zucchi
abstract
Kinematic viscosities of the binary 2-butanone (1) + 1,2-propanediol (2) solvent system have been measured for mixtures covering the whole miscibility range expressed by 0 less than or equal to x(i) less than or equal to 1, at 19 temperatures in the range -10 less than or equal to t/degreesC less than or equal to 80. The measured values have been used to test empirical equations that express the kinematic viscosities as functions of the composition and temperature. Excess kinematic viscosities (nu(E)) have also been calculated. Sign and magnitude of these quantities are discussed in terms of type and nature of specific intermolecular interactions. Furthermore, derived quantities such as thermodynamic parameters of viscous flow (DeltaGdouble dagger, DeltaHdouble dagger and DeltaSdouble dagger), are analyzed on the basis of Eyring's model. All the investigated excess mixing properties indicate the probable existence of stable two-component adducts in this binary solvent system.
2002
- Temperature and composition dependence of the refractive indices of the 2-chloroethanol + 2-methoxyethanol binary mixtures
[Articolo su rivista]
Cocchi, Marina; M., Manfredini; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali; Zanardi, Chiara; Zannini, Paolo
abstract
AbstractMeasurements of the refractive index n for the binary mixtures 2-chloroethanol + 2-methoxyethanol in the 0 ≤ T/°C ≤ 70 temperature range have been carried out with the purpose of checking the capability of empirical models to express physical quantity as a function of temperature and volume fraction, both separately and together, i.e., in a two independent variables expression. Furthermore, the experimental data have been used to calculate excess properties such as the excess refractive index, the excess molar refraction, and the excess Kirkwood parameter Ag over the whole composition range. The quantities obtained have been discussed and interpreted in terms of the type and nature of the specific intermolecular interactions between the components.
2002
- Vibrational Spectra of some Pigments from Pompei
[Relazione in Atti di Convegno]
Baraldi, Pietro; Fagnano, C.; Ghittoni, A. L.; Tassi, Lorenzo; Zannini, P.
abstract
identification of mural paintings in ancient excavations by Raman spectroscopy
2002
- Viscosity of (ethane-1,2-diol+1,2-dimethoxyethane + water) at temperatures from 263.15 K to 353.15 K
[Articolo su rivista]
Cocchi, Marina; M., Manfredini; Marchetti, Andrea; Pigani, Laura; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro; Zanardi, Chiara
abstract
AbstractThe kinematic viscosity ν for (ethane-1,2-diol + 1,2-dimethoxyethane + water) was measured at 14 different ternary compositions covering the whole miscibility field, and at 19 temperatures in the range 263.15 T / K 353.15. The experimental values were fitted using empirical equations of the type ν = ν (T) and ν = ν (xi), respectively, in order to provide reliable models to account for the behaviour of the system. The excess kinematic viscosity νEhas been determined and interpreted in terms of the type and nature of the interactions among the components of the mixture. Using the experimental ν data, the thermodynamic properties ( ΔG * , ΔH * ,ΔS * ) of the viscous flow have been obtained from the Eyring’s approach and standard thermodynamic equations. Furthermore, excess mixing functions, such asΔG * E , have been determined, and found to evidence the existence of quite strong specific interactions among the components, probably due to the formation of hydrogen bonds and dipolar networks. However, all the calculated excess mixing properties suggest the absence of stable three-component adducts.
2001
- Density and volume properties of the 2-methoxyethanol+1,2-dimethoxyethane + water ternary solvent system at various temperatures
[Articolo su rivista]
Cocchi, Marina; Marchetti, Andrea; Pigani, Laura; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari; Zanardi, Chiara
abstract
Densities (rho) of the ternary mixtures 2-methoxyethanol + 1,2-dimethoxyethane + water have been measured at 19 temperatures in the range -263.15 less than or equal toT/K less than or equal to 353.15. The experimental data were processed by empirical relations accounting for the dependence of rho on temperature and ternary composition expressed as mole fraction of the components (0 less than or equal to x(i) less than or equal to 1). All checked equations seem to be suitable for correlation purposes, in order to obtain interpolated values in correspondence to experimental data gaps. Furthermore, the excess molar volume (V-E) has been investigated to make evident the possibility of forming stable solvent-cosolvent adducts. The excess property has been interpreted on the basis of specific intermolecular interactions between the components.
2001
- Mass Transport Properties in Solvent Liquid Mixtures
[Articolo su rivista]
Cocchi, Marina; Manfredini, Matteo; A., Marchetti; Tassi, Lorenzo; Seeber, Renato; A., Ulrici
abstract
The study of mass transport properties, such as density and viscosity of mixed solvent systems (both aquomixed and nonaqueous liquids), have proven to be a very useful tool in investigating specific intermolecular interactions and structural effects in condensed phases of real components. The knowledge of these properties and of some related quantities is of strategic importance for a lot of technical and scientific applications, and the availability of correlation models with temperature and chemical composition, which can be employed both for interpretative and predictive calculations, is extremely useful for chemists, physics, biologists, practising engineers and research workers devoted to material sciences. Here, some of the most significant descriptive relationships will be summarised (together with their graphical representations), and some new concepts will be introduced to reach a better understanding about some Newtonian and pseudo-rheological complex systems. The chosen species for these studies pertain to the class of 1,2-ethanedyil-derivatives, such as 1,2-ethanediol (ED), 2-methoxyethanol (ME), 1,2-dimetho-xyethane (DME), di-ethylen-glycol (DEG), 1,2-propa- nediol (12PD), 2-butanone (MEK), in addition to water (W) and to DMF among other solvents, in order to construct a suitable data-base. Emphasis has been given to some aspects related to the peculiar hydrodynamic behaviour of water and to its binary and ternary mixtures. Furthermore, some aspects of excess mixing properties (YE) of multicomponent solvent systems are focused.
2001
- Refractive properties of binary mixtures containing N,N-dimethylformamide+2-methoxyethanol or 1,2-dimethoxyethane
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; Seeber, Renato; Tassi, Lorenzo; Zannini, Paolo
abstract
Refractive index (n) and related properties such as molar refraction (R) have been investigated for DMF+ME and DMF+DME binary mixtures over the entire composition range, at 15 different temperatures in the range 0 less than or equal to t/degreesC less than or equal to 70. Some relationships have been applied to study the dependence of the measured and derived quantities by temperature and composition. Furthermore, the excess functions n(E), R-E and the excess Kirkwood correlation parameters Deltag have been examined, in order to identify the presence of solvent-cosolvent adducts in these binary mixtures. The results obtained have been interpreted on the basis of specific intermolecular interactions between different species.
2001
- The 2-Methoxyethanol + 1,2-Dimethoxyethane + Water Ternary System: Static Relative Permittivity from -10 to 80 °C
[Articolo su rivista]
Cocchi, Marina; DE BENEDETTI, Pier Giuseppe; Marchetti, Andrea; Menziani, Maria Cristina; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Static relative permittivities of the 2-methoxyethanol + 1,2-dimethoxyethane + water ternary solvent system were measured as a function of temperature (-10 less than or equal to t/degreesC less than or equal to 80) and of composition, over the whole molar fractions range 0 less than or equal to x(1), x(2), x(3) less than or equal to 1. The experimental values have been used to test some empirical relationships accounting for the dependence of epsilon on T. x(i), and on T, x(i) couples of values. A comparison between calculated and experimental data shows that these relationships can be profitably employed to predict E values in correspondence to experimental data gaps. The excess dielectric permittivity, epsilon (E), assumes, in the most cases, negative values for any compositions of the mixtures. while the values of the excess molar polarization, PE, are positive. The large values of the excess quantities are indicative of the strong specific interactions among similar, as well as different molecules in the mixtures. Discussion of the data in terms of Kirkwood correlation factor also gives information on the short-range intermolecular interactions among the components. suggesting the formation of two-components adducts rather than of than mure complex moieties involving all three molecular species.
2001
- The Ethane-1,2-diol + 2-Methoxyethanol + 1,2-Dimethoxyethane Ternary Solvent System: Density and Volume Proprties at Different Temperatures.
[Articolo su rivista]
Cocchi, Marina; M., Manfredini; Marchetti, Andrea; Sighinolfi, Simona; Tassi, Lorenzo; Ulrici, Alessandro; M., Vignali
abstract
The density of the ethane-1,2-diol+2-methoxyethanol + 1,2-dimethoxyethane ternary mixtures has been measured at different temperatures ranging from-10 to 80° C, and over the whole composition range. The experimental data have been used to check the validity of some relationships accounting for the dependence of the density on temperature and composition, useful to evaluate the behaviour of this property in the whole temperature and composition domains. Starting from the primary data, some derived quantities, such as excess molar volumes, partial molar volumes and partial excess molar volumes, have been obtained. In these mixtures VE is generally negative at all the experimental conditions, showing the greatest deviations along the binary axes corresponding to the binary subsystems. The results are compared and discussed to get light to the changes in molecular association and structural effects in this solvent system.
2000
- Density and volume properties of ethane-1,2-diol + 1,2-dimethoxyethane + water ternary mixtures from -10° to 80°c
[Articolo su rivista]
Baraldi, Pietro; Franchini, Giancarlo; Marchetti, Andrea; G., Sanna; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari
abstract
Thermodynamic interactions in the ethane-1,2-diol (1) + 1,2-dimethoxyethane (2) + water (3) ternary system have been investigated in terms of the excess molar volume, derived from density measurements at 19 different temperatures from -10 degrees to 80 degrees C. Fourteen three-component mixtures have been considered, covering the entire composition range. The excess molar volumes are discussed in terms of conformational changes induced in each component by the presence of another one. The results obtained support the hypothesis of the absence of any three-component complex adducts under all experimental conditions investigated.
2000
- Density and volumetric properties of ethane-1,2-diol plus di-ethylen-glycol mixtures at different temperatures
[Articolo su rivista]
Cocchi, Marina; Marchetti, Andrea; Pigani, Laura; G., Sanna; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari; Zanardi, Chiara
abstract
The density of the ethane-1,2-diol (ED) + di-ethylen-glycol (DEG) binary mixtures has been measured at different temperatures over the complete composition range. The experimental measurements have been used to check the validity of relationships accounting for the dependence of the density on temperature and composition, useful to obtain interpolated values in the correspondence of the experimented data gaps. Starting from the primary data, some derived quantities, such as partial molar volumes, excess and partial excess molar volumes, have been obtained. In these mixtures, V-E presents an S-shaped dependence on composition at each temperature, showing negative values in the ED rich-region and positive values at the opposite extreme. The results are compared and discussed to get light to the: changes in molecular association and structural effects in this solvent system. (C) 2000 Elsevier Science B.V. All rights reserved.
2000
- Electrochemical synthesis and characterisation of polythiophene conducting polymers functionalised by metal-containing porphyrine residue
[Articolo su rivista]
B., Ballarin; Seeber, Renato; Tassi, Lorenzo; D., Tonelli
abstract
Two different copolymers of 2,2'-bitthiophene and of new thiophene derivatives, bearing in the beta position a porphyrin macrocycle, either free or complexed with Ni(II), have been electrogenerated and studied. The electrochemical behaviour of the relevant coatings has been compared, and the complexing ability of the macrocycle with respect to Ni(II) ion has been investigated. Moreover, the possibility of growing the metal-containing polymer on a micro Pt disk has been checked. The resulting modified microelectrode has been characterised and tested. (C) 2000 Elsevier Science S.A. All rights reserved.
2000
- Variation of volumic properties with temperature and composition of 2-butanone+1,2 propanediol binary mixtures
[Articolo su rivista]
Marchetti, Andrea; Palyi, Gyula; Tassi, Lorenzo; Ulrici, Alessandro; Zucchi, Claudia
abstract
In this work we present experimental values of the density (rho), and some related quantities such as excess molar volumes (V-E), of the 2-butanone + 1,2-propanediol binary mixtures at various temperatures in the -10 less than or equal to t / degreesC less than or equal to 80 range and as a function of mole fraction. The experimental results have been fitted to some relationships of the type rho = rho (T), rho = rho (x(i)), and rho = rho (T,x(i)) to estimate the property in correspondence of the experimental data gaps. The observed behaviour has been interpreted on the basis of specific interactions and molecular features of the components. (C) 2000 Elsevier Science B.V. All rights reserved.
1999
- Density and excess molar volume values of binary mixtures of 2-chloroethanol + 1,2-ethanediol
[Articolo su rivista]
FRANCHINI G., C; Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Vaccari, G.
abstract
Density of the 2-chloroethanol (CE) + 1,2-ethanediol (ED) binary solvent system are presented at 19 temperatures in the -10 < t/°C < 80 range. The measured values have been used to test some empirical equations of the type ro=ro(t), ro=ro(Xi) and ro=ro(t,Xi), in order to provide useful interpolation procedures to obtain calculated values corresponding to the experimental data gaps. From the primary data, the excess molar volumes (V^E) have been calculated. The sign and magnitude of this quantity have been discussed in term of the type and nature of binary interactions. Furthermore, the derived quantities have fitted the Redlich-Kister equation with very good accuracy. some
1999
- Development of Quantitative Structure-Property Relationships (QSPR) using calculated descriptors for the prediction of the physico-chemical properties (nD, r, bp, e and h) of a series of organic solvents.
[Articolo su rivista]
Cocchi, Marina; DE BENEDETTI, Pier Giuseppe; Seeber, Renato; Tassi, Lorenzo; Ulrici, Alessandro
abstract
Quantitative structure-property relationship (QSPR) models were derived for predicting boiling point (at 760 mmHg), density (at 25 °C), viscosity (at 25 °C), static dielectric constant (at 25 °C), and refractive index (at 20 °C) of a series of pure organic solvents of structural formula X-CH2CH2-Y. A very large number of calculated molecular descriptors were derived by quantum chemical methods, molecular topology, and molecular geometry by using the CODESSA software package. A comparative analysis of the multiple linear regression techniques (heuristic and best multilinear regression) implemented in CODESSA, with the multivariate PLS/GOLPE method, has been carried out. The performance of the different regression models has been evaluated by the standard deviation of prediction errors, calculated for the compounds of both the training set (internal validation) and the test set (external validation). Satisfactory QSPR models, from both predictive and interpretative point of views, have been obtained for all the studied properties.
1999
- Kinematic viscosities of ternary mixtures containing ethane-1,2-diol, 2-methoxyethanol and water from-10 degrees C to 80 degrees C
[Articolo su rivista]
Cocchi, Marina; Marchetti, Andrea; G., Sanna; Tassi, Lorenzo; Ulrici, Alessandro; G., Vaccari
abstract
Kinematic viscosities (v) of the ternary ethane-1,2-diol (1) + 2-methoxyethanol (2)+ water (3) solvent system have been measured for 36 ternary mixtures covering the whole miscibility range expressed by the condition 0 <X-1,X-2,X-3 < 1, at 19 temperatures in the range - 10 less than or equal to t (degrees C) less than or equal to 80. The measured values have been used to test some empirical equations of the type v = v(t) and v = v(X-i), in order to provide for useful interpolation procedures to obtain calculated values in correspondence to the experimental data gaps. From the experimental data, the excess kinematic viscosities (v(E)) have been calculated. Sign and magnitude of these quantities have been discussed in terms of type and nature of specific intermolecular interactions. Furthermore, derived quantities such as thermodynamic parameters of the viscous flow (Delta G*, Delta H* and Delta S*), have been analysed on the basis of the Eyring's model. All the investigated excess mixing properties indicate the probable absence of stable three-component adducts in this ternary solvent system. (C) 1999 Elsevier Science B.V. All rights reserved.
1999
- Refractive indices of binary mixtures of (1,2-dichloroethane + 2-chloroethanol) at various temperatures
[Articolo su rivista]
Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro; Vaccari, Giulia; G., Sanna
abstract
Measurements of the refractive index n(D) of(1,2-dichloroethane + 2-chloroethanol) in the temperature range 273.15 K less than or equal to T less than or equal to 343.15 K have been carried out for the purpose of checking the suitability of some empirical models of the type n(D) = n(T), n = n(x(i)), and n = n(T, x(i)) for the correlation and interpolation of experimental data to cover existing gaps. Furthermore, the experimental data have been used to calculate excess properties such as Delta n(D), R-E, and the excess Kirkwood parameter ag over the entire composition range. The results obtained have been discussed and interpreted in terms of the type and nature of the specific intermolecular interactions between the components.
1998
- Densities and excess molar volumes of the solvent (ethane-1,2-diol + 2-methoxyethanol + water) from T = 263.15 K to T = 353.15 K
[Articolo su rivista]
Marchetti, Andrea; Martignani, Alberto; Tassi, Lorenzo
abstract
Densities rho are reported for {ethane-1,2-diol (1) + 2-methoxyethanol (2) + water (3)} at 19 temperatures ranging from T = (263.15 to 353.15)K on 36 ternaries of different mole fractions covering the whole miscibility field 0 < x(1)/x(2)/x(3) < 1. The experimental data have been used to test some empirical equations expressing the functions rho = rho(T) and rho = rho(x(1), x(2), x(3)), and the excess molar volumes V-E have been derived and used to investigate the presence of three component stable adducts in these mixtures.
1998
- Density and excess molar volumes of binary mixtures of 1,2-dichloroethane plus 2-chloroethanol from -10 to 80 degrees C
[Articolo su rivista]
Marchetti, Andrea; A., Martignani; Tassi, Lorenzo
abstract
Densities (rho) were measured for the 1,2-dichloroethane (DCE) + 2-chloroethanol (CE) at 19 temperatures in the range -10 less than or equal to t/C-0 less than or equal to 80. The experimental data were used to test some empirical relations giving the dependence of the density on the temperature and binary composition: rho = rho(t), rho = rho(X-1) and rho = rho(t, X-1). From the experimental data, the excess molar volumes (V-E) were calculated. The VE values are always positive. This quantity has been interpreted in terms of geometric effects (interstitial accomodation) and possible specific interactions (hydrogen bonding and dipolar interactions) which occur between components.
1998
- L`Aceto Balsamico e la Tradizione Scientifica
[Altro]
Franchini, Giancarlo; Marchetti, Andrea; Tassi, Lorenzo
abstract
L'Aceto Balsamico Tradizionale di Modena si presenta come un liquido sciropposo, denso, acetoso, di colore scuro, acido e dolce allo stesso tempo, dotato di un aroma fragrante e tipico. La particolare tecnica produttiva prevede: i) la cottura del succo d’uva, ottenuto da uve tipiche selezionate, per la preparazione del mosto cotto, ii) un processo di acetificazione a partire dal mosto cotto, iii) una fase di invecchiamento entro vaselli, botticelle di legni pregiati, effettuando rincalzi annuali sino al completamento della maturazione1, con conseguente affinamento delle caratteristiche organolettiche tipiche del prodotto.
1998
- The 2-methoxyethanol+1,2-dimethoxyethane binary solvent system. Refractive index and related properties from 0 to 70°C
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; Tassi, Lorenzo; G., Vaccari
abstract
The refractive properties of binary system containing 2-methoxyethanol (ME) and 1,2-dimethoxyethane (DME) have been measured at 15 temperatures in the range, working with the two pure species and 9 mixtures of them, covering the whole miscibility field ( ). Many equations have been checked in order to establish the best relationships stating the dependence of n on temperature and binary composition, by taking into account both the mole fraction (rational) scale and the volume fraction scale. Furthermore, the excess functions nE and RE (excess molar refraction) have been evaluated in order to investigated the existence of solvent-cosolvent complex adducts. As an evidence, we can suggest the presence of two complex moieties, namely 1ME 1DME and 2ME 1DME, which seem to be both thermostable at all investigated temperatures.
1997
- Density and volumetric behavior of 1,2-dimethoxyethane plus water binary mixtures from -10 to 80 degrees C
[Articolo su rivista]
Marchetti, Andrea; Tassi, Lorenzo; Ulrici, Alessandro
abstract
The densities (rho) and excess molar volumes (V-E) for 1,2-dimethoxyethane + water binary mixtures were determined, when possible, at 19 different temperatures ranging from -10 up to +80 degrees C. The experimental measurements were used to test some empirical relations giving the dependence of the density on the temperature and binary composition: rho = rho(t), rho = rho(X-1), and rho = rho(t,X-1). Furthermore, the results of V-E calculations are discussed in terms of the influence of interactions between the components, of the order and degree of packing in the mixtures, and of the free-volume differences.
1997
- Thermophysics of multicomponent nonelectrolytic solutions
[Capitolo/Saggio]
Marchetti, A.; Tassi, Lorenzo
abstract
Thermophysical properties of nonelectrolytic solutions have proven to be a very useful tool in elucidating the structural interactions among components. For example, density, viscosity, dielectric constant and refractive index can be used to study solvent - solvent specific interactions as afunction of temperature, while the composition dependence provides valuable and unsubstituible information about the presence and teh stoichiometry of complex adducts. In many cases, all of this information can be employed in a complementary fashion to clarify the macro- and microscopic behaviour of electrolytic solutions too. In this paper we will deal deal first of all with the above mentioned properties in aqueous and nonaqueous solutions, both binary and ternary mixtures , containing 1,2-ethanedyil derivatives such as 1,2-ethanediol (ED); 2-methoxyethanol (ME); 1,2-dimethoxyethane (DME); 2-chloroethanol (CE); 1,2dichloroethane (DCE); in addition to water (W) and DMF among other species. It is well recognized that correlation procedures of physical properties are and will always be valuable aids to practicing engineers and chemists, because of their extensive employment for predictive calculations in research, development, process design and analysis. Therefore, particular emphasiswill be given to these aspects and some standpoints will be discussed. Furthermore, careful attention will be paid about excess mixing properties and the pseudo-ideality condition which is sometimes encountered when working with binary and more complex solvent systems.
1997
- Viscosimetric studies on 2-methoxyethanol plus 1,2-dimethoxyethane binary mixtures from -10 to 80 degrees C
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo
abstract
The kinematic viscosities (v) were measured for nine binary solvent mixtures of 2-methoxyethanol (ME) + 1,2-dimethoxyethane (DME) at nineteen temperatures ranging from -10 to + 80 degrees C. The experimental data have been used to test some empirical equations of the type v = v(T), v = v(X-1) and v = v(T, X-1). The viscosities of all the mixtures increase from the values of pure DME to that of ME as the mole fraction of ME increases, and always yield a negative excess property (v(E)) all the investigated temperatures. Furthermore, thermodynamic parameters of viscous flow have been evaluated on the basis of the Eyring theory. The excess flee energy of activation of viscous flow (Delta G(*E)) vs X-2 plot suggests the presence of a stable hetero-adduct, having ME : DME = 1 : 1 stoichiometric ratio.
1996
- Kinematic viscosity and viscous flow in binary mixtures containing ethane-1,2-diol
[Capitolo/Saggio]
Tassi, Lorenzo
abstract
It has been a long time since dispersion and specific interactions in nonelectrolytic liquid mixtures involving both non-hydrogen bonding and hydrogen bonding solvent types have been studied by applying many and very different experimental techniques, such as thermomechanic (density, viscosity, dielectric, and refractive properties are the most common) and thermodynamic (heat of mixing) measurements, in addition to spectroscopic techniques, IR and NMR in particular[1]. A literature survey reveals many of transport properties of fluid, a primary source of fundamental data for the solution of practical problems about heat and mass transfer in real systems, for processes development, and engineering design. Furthermore, in recent years the employment of computer simulation methods of molecular dynamics has properties in dense fluids and a greater understanding of molecular motions and interactions' patterns in such systems [2] and [3].
1996
- Relative permittivity analysis of N,N-dimethylformamide plus 1,2-dichloroethane binary mixtures
[Articolo su rivista]
Tassi, Lorenzo
abstract
The dielectric behaviour of binary mixtures of N,N-dimethylformamide (DMF) + 1,2-dichloroethane (DCE) has been studied at 19 temperatures in the -10 less than or equal to t/C-0 less than or equal to +80 range, employing the pure species and 9 mixtures of theirs covering the whole composition range (0 less than or equal to X(i) less than or equal to 1). Some fitting procedures have been applied in order to check the suitability of empirical relations of the type epsilon = epsilon(T), epsilon = epsilon(X(i)) and epsilon = epsilon(T, X(i)). Furthermore, the excess function (epsilon(E)) has been evaluated in order to investigate the possibility of existence of complex moieties. The DMF . DCE adduct appears to be the only stable heteroassociated species.
1996
- Static dielectric constants of 1,2-dichloroethane + 2-methoxyethanol + 1,2-dimethoxyethane ternary liquid mixtures from -10 to 80 °C
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo
abstract
Static dielectric constants (epsilon) were measured for mixtures of 12-dichloroethane (DCE, 1) + 2-methoxyethanol (ME, 2) + 1,2-dimethoxyethane (DME, 3) at 19 temperatures in the range -10 less than or equal to t/degrees C less than or equal to 80, employing 12 ternaries covering the whole composition range expressed by the mole fractions 0 < X(1), X(2), X(3) < 1. Empirical fitting equations of the type epsilon = epsilon(T), epsilon = epsilon(X(i)) and epsilon = epsilon(T,X(i)), which might be useful for correlation and interpolation procedures, were used to represent the experimental data. The excess mixing property epsilon(E) has been evaluated to investigate the presence of solvent-cosolvent adducts at each temperature. The quantity epsilon(E) has been found to be partly positive and partly negative in the ternary domain {X(1), X(2), X(3)}. As a consequence, it is possible to observe an isoline at epsilon(E) = 0 at each temperature. Such a line represents a large set of ternary mixtures having a pseudo-ideal dielectric behavior, even being formed by interacting components.
1996
- Volumetric behaviour of the ethane-1,2-diol+1,2-dimethoxyethane binary solvent system
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; C., Preti; Tassi, Lorenzo
abstract
Densities have been measured for 11 binary mixtures of ethane-1,2-diol (ED, component 1) + 1,2-dimethoxyethane (DME, component 2), whose composition covers the whole miscibility field (0 less than or equal to X(1) less than or equal to 1), at 19 temperatures in the range -10 less than or equal to t/degrees C less than or equal to +80. The experimental data were used to test some empirical relationships of the general form rho = rho(t), rho = rho(X(1)) e rho = rho(t,X(1)). Furthermore, the experimental densities have been converted into the corresponding excess molar volumes (V-E), which have been discussed and interpreted in terms of the specific intermolecular interactions. The V-E against X(2) plots suggest the presence at each temperature of a more stable heteroaggregated complex species, at a stoichiometric ratio ED:DME = 2:1.
1995
- ASSOCIATING BEHAVIOR OF MIXED LIQUIDS - DIELECTRIC-PROPERTIES OF THE ETHANE-1,2-DIOL+1,4-DIOXAN SOLVENT SYSTEM FROM -10-DEGREES-C TO +80-DEGREES-C
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
The associating behaviour of ethane-1,2-diol (component 1)+1,4-dioxan (component 2) in their binary mixtures has been investigated through their dielectric properties. The experimental measurements of the relative permittivity (epsilon) in the temperature range -10 less than or equal to t/degrees C less than or equal to 80 for nine binary mixtures covering the whole miscibility field 0 less than or equal to X(1) less than or equal to 1 have been utilized to test empirical equations representing the functions epsilon = epsilon(T), epsilon = epsilon(X(1)) and epsilon = epsilon(T, X(1)) Furthermore, the excess mixing function, epsilon(E), has been evaluated to obtain qualitative and quantitative information about the possibility of 'solvent-cosolvent' complex formation.
1995
- Block "f" metal complexes with Benzodiazepines. Cytostatic and antiviral biological studies
[Articolo su rivista]
G. C., Franchini; Marchetti, Andrea; C., Preti; Tassi, Lorenzo; G., Tosi; Zannini, Paolo
abstract
n.d.
1995
- Density and volumic properties of N,N-dimethylformamide +2-methoxyethanol+1,2-dimethoxyethane liquid ternary mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo
abstract
Densities (rho) at various temperatures ranging from -10 up to +80 degrees C have been measured for N,N-dimethylformamide+2-methoxyethanol+1,2-dimethoxyethane ternary solvent system, employing 66 mixtures covering the whole miscibility field. Polynomial equations describing the dependence on temperature, rho=rho(t/degrees C), and molar composition, rho=rho(X(1),X(2)), have been checked. Furthermore, the excess molar volumes (V-E), derived from rho values, can provide useful suggestions about the formation of solvent-cosolvent complexes. Excess molar volumes have been interpreted on the basis of specific interactions between unlike molecules, taking into account geometric effects and steric hindrances. The V-E quantities have been isothermally fitted by an empirical relation of the type V-E=V-E(X(1),X(2),X(3)) formally derived from the well known Redlich-Kister equation. As a rule, for all the here tested relationships, the calculated values agree very well with the experimental ones, indicating that all the equations can be safely employed fdr predictive calculations in correspondence of the experimental data gaps.
1995
- Dielectric characterization of binary solvents containing 1,2-dichloroethane and 2-chloroethanol
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; A., Varini
abstract
Static dielectric constants (epsilon) were determined for the 1,2-dichloroethane (DCE, 1)/2-chloroethanol (CE, 2) binary solvent system at 19 temperatures ranging from -10 to +80 degrees C and in the whole composition range expressed by the mole fraction 0 less than or equal to X(1) less than or equal to 1. The experimental values have been fitted to some equations that could be usefully employed for predictive epsilon calculations. Furthermore, the excess mixing properties (epsilon(E)) have been evaluated in order to point out the presence of solvent-cosolvent adducts in the binary mixtures mentioned above. The values of epsilon(E) have been generally found to be negative and only slightly positive under a few experimental conditions in the CE rich-region, thus giving evidence of a close interaction network probably via hydrogen bonding as well as other interactions of every kind in this solvent system.
1995
- Dielectric properties of binary mixtures of 1,2-dichloroethane plus ethane-1,2-diol and 1,2-dichloroethane plus 2-methoxyethanol
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; C., Preti; M., Tagliazucchi; Tassi, Lorenzo
abstract
The dielectric behaviour of binary mixtures of 1,2-dichloroethane (DCE)/ethane-1,2-diol (ED) and DCE/2-methoxyethanol (ME) has been studied at 19 temperatures in the range from -10 to +80 degrees C. The DCE/ED system is immiscible, except in a narrow range near the ED-rich region. The DCE/ME system, which is completely miscible, has been investigated over the whole composition range. Fitting procedures have been applied in order to check the suitability of empirical or semiempirical functions of the type epsilon(T), epsilon(X(i)) and epsilon(T,X(i)). Furthermore, the excess static dielectric constant, epsilon(E), has been evaluated in order to investigate the possibility of the existence of complex entities. A DCE.2ME species appears to be the only stable adduct.
1995
- Investigation on the viscosi metric properties of 1,2-ethanediol+1,2-dimethoxyethane binary mixtures
[Articolo su rivista]
Corradini, Fulvio; Marchetti, Andrea; Tagliazucchi, Mara; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The kinematic viscosity of pure ethane 1,2-diol, 1,2-methoxyetane and nine binary mixture at 19 temperatures ranging from -10 to 80 C has been measured.
1995
- Static dielectric constants of 1,2-dichloroethane + 1,2-dimethoxyethane binary mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo
abstract
Static dielectric constants (epsilon) have been measured for pure 1,2-dichloroethane, 1,2-dimethoxyethane, and for 9 of theirs binary mixtures over the entire composition range and at 19 temperatures ranging from -10 up to +80 degrees C. The experimental data have been fitted by some empirical or quasi-theoretical equations of the type epsilon=epsilon(T), epsilon=epsilon(X(1)), and epsilon=epsilon(T,X(1)). Furthermore, the shift from ideality has been taken into account and evaluated on the basis of excess function epsilon(E) Positive deviations are detected at all experimental conditions, and a maximum occurs in the excess quantity, showing the existence of a stable solvent-cosolvent complex adduct at the stoichiometric ratio DCE : DME = 1 : 1, which may be interpreted in terms of moderately weaker interactions such as dipolarity and polarizability between dissimilar molecules.
1995
- The 1,2-dimethoxyethane - water solvent system. Viscokinetic and thermodynamic properties of viscous flow from -10 to 80 °C
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; A., Varini
abstract
Kinematic viscosity (v) has been measured for pure 1,2-dimethoxyethane, and for nine of its binary mixtures with water, covering the whole miscibility field, and working at 19 temperatures in the -10 less than or equal to t/degrees C less than or equal to 80 range. The properties investigated have been fitted by some empirical equations of the type v=v(T) and v=v(X(1)). Starting from the experimental viscosities, the thermodynamic parameters (Delta G*, Delta H*, Delta S*) of the viscous flow in these binaries have been obtained by applying the Eyring approach and the standard thermodynamic equations. Furthermore, the excess functions, such as v(E) and Delta G(*E) have been evaluated, showing the existence of quite strong specific interactions between the components, probably via hydrogen bonding and a dipolar network. Experimental variations in the Delta G(*E) quantity with temperature were very useful in order to depict and differentiate the trend in three well defined composition regions, namely M(I), M(II), and M(III), which are probably characterized by different patterns in molecular aggregation between similar and/or non similar species.
1995
- The N,N-dimethylformamide + 2-methoxyethanol binary mixtures. Viscosity and activation energy of viscous flow at various temperatures
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo
abstract
Dynamic viscosity (eta) of binary solvent mixtures of N,N-dimethylformamide (DMF, component 1)+ 2-methoxyethanol (ME, component 2) has been investigated at 19 temperatures ranging from -10 to +80 degrees C. Some empirical equations have been applied in order to establish the best regression fitting procedures eta=eta(T), eta=eta(X(1)) and eta=eta(T,X(1)). For this binary solvent system, the viscometric properties are continuous but not linear functions of the mixture composition. Therefore, experimental eta values were used to calculate the excess viscosities (eta(E)) and excess Gibbs activation energies (Delta G*(E)) of viscous flow. Both these quantities strongly deviate from ideality over the whole composition range of the investigated mixtures. Furthermore, deviations from the ideal behaviour could be very useful in order to evidentiate the formation of solvent-cosolvent complex species and to evaluate their stoichiometrical composition.
1995
- Thermodynamics of viscous flow in ethane-1,2-diol + water binary mixtures.
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Kinematic Viscosities (nu) of pure ethane-1,2-diol (component 1) and of nine mixtures with water (component 2) were measured at 19 temperatures ranging from -10 to +80 degrees C, and for binary compositions covering the whole miscibility field expressed by the relation 0 less than or equal to X(1) less than or equal to 1. The property fitted some empirical equations in terms of the dependences nu = nu(T) and nu(X(1)), where T is the thermodynamic temperature and X(1) is the mole fraction of ethane-1,2-diol. Furthermore, the excess function (nu(E)) and the excess Gibbs energy of activation of viscous flow (Delta G*(E)) have been investigated. The trend of nu(E) against binary composition of the mixtures shows negative deviations from ideal behaviour, while the contrary is true for Delta G*(E) The results indicate specific molecular interactions between the components, and an overview is given on the basis of the molecular dynamics of the pure species.
1994
- 2-methoxyethanol - water solvent system : static relative permittivity from -10 to 80°C
[Articolo su rivista]
F., Corradini; Marcheselli, Luigi; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
A detailed dielectric study of 2-methoxyethanol (ME)-water (W) mixtures has been carried out as a function of temperature in the range - 10 to + 80-degrees-C and over the entire binary composition range (0 less-than-or-equal-to x less-than-or-equal-to 1). The experimental data, obtained by the heterodyne beat method at 2 MHz, were used to test some empirical relations of the type epsilon = epsilon(T), epsilon = epsilon(x) and epsilon = epsilon(T, x), in order to assess the empirical performances in dielectric behaviour of these mixtures, including the experimental conditions which are able to modify such patterns. The data reported here for ME-W binary mixtures were useful trying to understand the relative discriminating ability of both components towards cooperative intermolecular interactions in the liquid state, the quantitative similarities and differences between the chosen pure species, the intermolecular phenomena and interactions influencing the dielectric properties of the mixtures and the usefulness of a qualitative description of the possible formation of solvent-cosolvent complex species involving hydrogen-bonding, dipole-dipole and other interactions.
1994
- DENSITIES AND EXCESS MOLAR VOLUMES FOR BINARY-MIXTURES OF N,N-DIMETHYLFORMAMIDE PLUS 1,2-DIMETHOXYETHANE
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Densities p are reported for N,N-dimethylformamide and 1,2-dimethoxyethane binary mixtures at different mole fractions covering the whole miscibility range and at 19 temperatures ranging from -10 to 80-degrees-C. The experimental density data have been filled by empirical relations and the excess volumes by a Redlich-Kister equation. The 1:1 N,N-dimethylformamide and 1,2-dimethoxyethane adduct appears to be stable throughout the temperature range. A comparison with other DMF containing mixtures is made.
1994
- Dielectric behaviour of the N,N-dimethylformamide + 2-methoxyethanol + 1,2-dimethoxyethane ternary solvent system from -10° to + 20°C
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The static relative permittivities, epsilon, and excess properties, epsilon(E), of the ternary mixtures N,N-dimethylformamide (DMF)-2-methoxyethanol (ME)-1,2-dimethoxyethane (DME) have been measured at several temperatures in the range -10 to +20-degrees-C. This ternary system shows interesting properties for use as a mixed solvent and for electroanalytical applications. The study of these mixtures should help to increase our understanding of the co-solvation of ionizable and inert solutes. The behaviour of epsilon(E) is quite interesting because this quantity assumes partly positive and partly negative values in the composition domain. As a consequence, there are mixtures which have epsilon(E) = 0, indicating ideal dielectric mixing behaviour. The excess property is discussed in terms of the influence of specific interactions between components, the order and degree of packing in the mixtures and any other effects which produce long-range structure in these mixed liquids.
1994
- Electrolytic dissociation of sodium tetraphenylborate in 2-methoxyethanol / water binary solvent mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Thermodynamic properties from conductance data are reported for the NaBPh4 electrolytic solutions in 2-methoxyethanol (component 1)/water (component 2) binary solvent mixtures, working at 19 temperatures ranging from -10 to +80-degrees-C and for 6 mixtures covering the 0.1865 less-than-or-equal-to x1 less-than-or-equal-to 1 composition range. Experimental conductivity data were analysed using the Fuoss-Hsia equation, and the chosen salt was found to associate to a certain extent in these solvent mixtures. The resulting dissociation constants (K) of the ion-pair have been used to test some empirical equations K = K(T), K= K(x1), and K = K(T, x1). Furthermore, the present findings have been compared with our previously reported results from working with picric acid in the same mixtures and experimental conditions.
1994
- INVESTIGATIONS ON THE VISCOMETRIC PROPERTIES OF ETHANE-1,2-DIOL+1,2-DIMETHOXYETHANE BINARY-MIXTURES
[Articolo su rivista]
Corradini, F; Marchetti, Andrea; Tagliazucchi, M; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The kinematic viscosity (nu) of pure ethane-1,2-diol (ED), 1,2-dimethoxyethane (DME) and nine binary mixtures at nineteen temperatures ranging from -10 to +80-degrees-C has been measured. The experimental values have been used to test some empirical equations of the type nu = nu(T) and nu = nu(x1), which are also suitable for data fits in the case of strongly associated dipolar components in the mixtures. The chainlike self-association of ED is widely reflected in its viscosity, which is considerably greater than that of DME. The viscosities of all the mixtures increase on passing from the values of pure DME to pure ED as the mole fraction of ED increases, and the mixing process always gives rise to negative excess properties (nu(E)) at all the temperatures investigated. Furthermore, thermodynamic parameters of viscous flow have been evaluated on the basis of Eyring's theory.
1994
- Investigations of viscometric properties of 1,2-ethanediol + 1,2-dimethoxyethane binary mixtures
[Articolo su rivista]
Corradini, F.; Marchetti, Andrea; Tagliazucchi, M.; Tassi, Lorenzo; Tosi, G.
abstract
Kinematic Viscosities of pure ethane-1,2-diol (ED,1) and of nine mixtures with 1,2-dimethoxyethane (DME, 2) were measured at 19 temperatures ranging from -10 to +80 °C, and for binary compositions covering the whole miscibility field expressed by the relation 0 less than or equal to X(1) less than or equal to 1. The property fitted some empirical equations in terms of the dependences nu = nu(T) and nu(X(1)). Furthermore, the excess function (nu(E)) and the excess Gibbs energy of activation of viscous flow (Delta G*(E)) have been investigated. The trend of nu(E) against binary composition of the mixtures shows negative deviations from ideal behaviour. The results indicate specific molecular interactions between the components, and an overview is given on the basis of the molecular dynamics of the pure species.
1994
- The relative permittivity of the ternary 1,2-ethanediol + 2-methoxyethanol + water solvent system
[Articolo su rivista]
F., Corradini; Marcheselli, Luigi; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
For many multicomponent cosolvent systems which can be important in electrochemical studies as far as in practical applications, the relative permittivity (epsilon) is a continuous but nonlinear function of the solvent composition. Rational functions were applied to the 1,2-ethanediol (1)+2-methoxyethanol (2)+water (3) ternary mixtures data at various temperatures (50 less-than-or-equal-to t/degrees-C less-than-or-equal-to 80) instead of the more conventional polynomial regressions for epsilon=epsilon(X(i)). These rational functions seem to be more adequate than the other polynomials, being reduced the number of required adjustable coefficients; in fact only a first power dependence on mole fraction (X(i)) is necessary, and a computational simplicity in reproducing reliable epsilon values over the total mole fraction 0 less-than-or-equal-to X1/X2/X3 less-than-or-equal-to 1 range is achieved. Furthermore, the calculated excess function (epsilon(E))is always negative, confirming the existence of rather strong interaction between components, probably via hydrogen bonding networks. Changes with temperature in epsilon(E) for these ternary mixtures seem to be very useful in order to depict and differentiate the experimental trend in three well distincted regions (namely M(I),M(II),M(III)) which are likely characterized by different specific interactions between like and/or unlike species. Nevertheless, no evidence for a three component adduct was obtained.
1994
- Thermodynamic analysis of viscosity data of ethane-1,2-diol + 1,4-dioxan binary mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Kinematic viscosities (nu) have been measured for pure ethane-1,2-diol, 1,4-dioxan and for nine of their mixtures covering the entire composition range and, where possible, at 19 temperatures from -10 to +80-degrees-C. The experimental values were converted into dynamic viscosities (eta) and were correlated with temperature and binary composition by some empirical equations. Furthermore, the excess function eta(E) and the excess Gibbs energy of activation of viscous flow DELTAG*E have been evaluated. Negative deviations from ideality are always observed for this binary system, this fact indicating strong specific interactions between unlike entities in solution to form stable solvent-cosolvent adducts. Activation enthalpies and entropies for viscous flow have been derived, and their dependence on binary composition is also discussed.
1994
- Transport and structural properties of alkali-metal bromides in 2-methoxyethanol solutions
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Limiting molar conductivity data for alkali-metal bromides MBr (M=Li, Na, K, Rb, Cs) in 2-methoxyethanol solutions at 19 different temperatures in the -10 less-than-or-equal-to t/degrees-C less-than-or-equal-to 80 range have been used to test some correlation functions. The LAMBDA0 values have been apportioned into individual ionic contributions (lambda0,i) using the tetraphenylphosphonium tetraphenylborate reference electrolyte method, and the temperature dependence of these quantities follows the equation of Speedy and Angell, lambda0,i = A0(T/T(S) - 1)gamma. The activation energies for ionic mobilities have been evaluated from the Arrhenius equation, providing evidence that in these solutions the ionic migration at 25-degrees-C of cations and anions follows the sequences Na+ < PPh4+ < Li+ congruent-to K+ < Rb+ < Cs+ and BPh4- < Br- respectively. Other quantities such as ionic radii in solution and solvation numbers have been derived by applying literature approaches.
1994
- Volumetric behaviour of 2-methoxyethanol + 1,2-dimethoxyethane binary mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Thermodynamic interactions in 2-methoxyethanol (component 1)+1,2-dimethoxyethane (component 2) binary mixtures have been studied in terms of the excess molar volume from the densities, measured at 19 temperatures between -10 and 80-degrees-C, for nine binary mixtures covering the whole miscibility field expressed by the mole fraction 0 less-than-or-equal-to X1 less-than-or-equal-to 1. Excess molar volumes are discussed in terms of induced conformational changes in each component in the presence of the other. The present findings support a hypothesis about the formation of a solvent-cosolvent complex species which has a well defined 1:1 stoichiometric composition and is thermostable under the experimental conditions.
1993
- A NON-LINEAR CORRELATION MODEL FOR THE RELATIVE PERMITTIVITY OF TERNARY AMPHIPROTIC (SOLVENT) MIXTURES
[Articolo su rivista]
F., Corradini; Marcheselli, Luigi; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Relative permittivities (epsilon) were determined for ternary ethane-1,2-diol (component 1)/2-methoxyethanol (component 2)/water (component 3) mixtures at five temperatures ranging from 5 to 25-degrees-C and over the mole fraction composition range 0 less-than-or-equal-to X(i) less-than-or-equal-to 1. The data have been fitted to a model equation that could be useful for predictive epsilon calculations. From the measured epsilon values, the excess relative permittivity epsilon(E) has been evaluated in order to test for three-component adducts. The values of epsilon(E) have been found to be negative for all the ternary mixtures under all the experimental conditions, which suggests a strong interaction network through hydrogen bonding, although evidence for a discrete three-component adduct was not forthcoming.
1993
- Conductances of sodium tetraphenylborate in 2-methoxyethanol - water binary solvent mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Conductance measurements have been carried out on the mixed 2-methoxyethanol (component 1)-water (component 2) solvent system for NaBPh4 solutions at 19 temperatures ranging from - 10 to + 80-degrees-C, and for six binary solvent mixtures covering the 0.1865 less-than-or-equal-to x1 less-than-or-equal-to 1 mole fraction range. The experimental data were processed by the more general Fuoss-Hsia equation, which provides the limiting molar conductance (LAMBDA0). This quantity is well fitted to the function proposed by Speedy and Angell (R. J. Speedy and C. A. Angell, J. Chem. Phys., 1976, 65, 851), LAMBDA0 = LAMBDA0(T/T(s) - 1)gamma, with a singular temperature T(s) for each binary mixture, where A0 and gamma are constants. Furthermore, the activation energy for the limiting equivalent conductivity has been evaluated on the basis of an Arrhenius equation and discussed in terms of the structural solvent-cosolvent complex adduct formation.
1993
- Conductivity of tetraphenylphosphonium bromide in 2-methoxyethanol - water
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
Thermodynamic properties from conductance data are reported for solutions of Ph4PBr in 2-methoxyethanol-water binary solvent mixtures, at 19 temperatures in the range -10 to +80-degrees-C and for six mixtures in the composition range 0.1865 less-than-or-equal-to X1 less-than-or-equal-to 1. The experimental conductivity values were analysed by the Fuoss-Hsia equation, and the salt was found to be associated to some extent in these mixtures. The experimental dissociation constant (K) of the ion pair for this electrolyte has been used to test some empirical equations representing the functions K = K(T), K = K(X1) and K = K(T, X1).
1993
- Dielectric properties of ethane-1,2-diol + 2-methoxyethanol + water liquid ternary mixtures
[Articolo su rivista]
F., Corradini; M., Malagoli; Marcheselli, Luigi; Marchetti, Andrea; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The dielectric properties of ethane-1,2-diol (1) + 2-methoxyethanol (2) + water (3) were measured in the range 30 less-than-or-equal-to t/degrees-C less-than-or-equal-to 50 and for 66 ternary mixtures covering the whole miscibility field (0 less-than-or-equal-to x1/x2/x3 less-than-or-equal-to 1). The epsilon values were analyzed by some empirical equations based on the pure-component properties for the ternaries studied. A comparison of the experimental and calculated data shows that the selected equations can be safely employed to predict the dependence of epsilon on the temperature and on the composition of the systems studied when binary and/or ternary experimental data are not available.
1993
- ETHANE-1,2-DIOL WATER SOLVENT SYSTEM - RELATIVE PERMITTIVITY AS A FUNCTION OF TEMPERATURE AND BINARY COMPOSITION
[Articolo su rivista]
F., Corradini; L., Marcheselli; Tassi, Lorenzo; G., Tosi
abstract
Relative permittivity (epsilon) data for several aqueous binary mixtures of ethane-1,2-diol at various temperatures in the range -10 to + 80-degrees-C are presented. The experimental data were processed by empirical relations stating the dependence of epsilon on temperature and binary composition expressed as mole fraction of ethane-1,2-diol. The variation of epsilon with mole fraction is non-linear at the temperatures investigated. Ethane-1,2-diol behaves as a structure breaker, showing negative deviations in epsilon vs. composition curves. Minima occur in the excess function (epsilon(E)), and the magnitude of the deviations with respect to pure species seems to be influenced by the dipolarity, polarizability and any hydrogen-bonding tendency of the two cosolvents. These empirical patterns in dielectric behaviour were very useful in order to establish the stoichiometric ratio of the ethane-1,2-diol-water solvent-cosolvent adduct which is probably formed in solution.
1993
- Ionic association of alkali-metal bromides in 2-methoxyethanol
[Articolo su rivista]
Tassi, Lorenzo
abstract
Conductance data are reported for alkali-metal bromides MBr (M = Li, Na, K, Rb, Cs), NaBPh, and Ph4PBr in 2-methoxyethanol at 19 temperatures in the - 10 less-than-or-equal-to t/-degrees-C less-than-or-equal-to 80 range. The experimental data were processed by the Fuoss-Hsia equation which provides the dissociation constant (K), the limiting equivalent conductivity (lambda(o)), and the ion-size fitting parameter (a). All the studied electrolytes were found to be associated to form solvent-separated ion-pairs in solution. The thermodynamic behaviour of the investigated solutions has been derived by analysing the dissociation constant values. Ionic limiting equivalent conductances for all the species were calculated using the fundamental assumption of Ph4PBPh4 as reference electrolyte.
1993
- KINEMATIC VISCOSITIES OF BINARY-MIXTURES OF 1,2-ETHANEDIOL AND 2-METHOXYETHANOL AT DIFFERENT TEMPERATURES
[Articolo su rivista]
Marchetti, Andrea; Tagliazucchi, M; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Kinematic viscosities have been measured for 1,2-ethanediol, 2-methoxyethanol and nine binary mixtures thereof over the entire composition range and at 19 temperatures ranging from - 10 to 80-degrees-C. Several empirical relations (e.g. McAllister, Heric, Lobe, Grunberg-Nissan and polynomial equations) have been used in order to fit the experimental data and to correlate the binary mixture results with the kinematic viscosities of the pure components. All these approaches correlate the kinematic viscosity data well, while the adjustable parameters provide some useful information about the specific interactions between different molecules.
1993
- Kinematic viscosities of 1,2-ethanediol / 1,4-dioxane binary mixtures from -10 to +80 °C
[Articolo su rivista]
F., Corradini; L., Marcheselli; Tassi, Lorenzo; G., Tosi
abstract
Mixture kinematic viscosities (nu) were measured for the 1,2-ethanediol/1,4-dioxane binaries, covering the whole miscibility field (0 less-than-or-equal-to X1 less-than-or-equal-to 1), at 19 temperatures ranging from -10 to +80-degrees-C. The experimental nu values were fitted by different equations, such as Grunberg-Nissan, McAllister, Auslander, Heric, and polynomial one, using pure component properties for the binaries studied. A comparison of the calculated and experimental data shows that all the selected equations can be safely employed to predict the dependence of nu on the composition and on the temperature of the system studied when no binary experimental data are available.
1993
- Kinematic viscosity studies of the binary ethane-1,2-diol / N,N-dimethylformamide solvent system at various temperatures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Kinematic viscosity data (nu) are presented for ethane-1,2-diol, for N,N-dimethylformamide and for nine binary mixtures in the - 10-degrees-C to 80-degrees-C temperature range. The experimental data were fitted by several empirical relations such as Grunberg-Nissan (1949), McAllister (1960), Heric (1966), Lobe (1973), Auslander (1964) and polynomial equations. Some considerations regarding the meaning of the obtained adjustment parameters are made. Furthermore, a new best fit equation is proposed and its validity has been compared to that of the other relations on the basis of the reproducibility of the experimental data.
1993
- N,N-dimethylformamide + 1,2-dimethoxyethane binary mixtures. The static dielectric constant from 40 to 80°C
[Articolo su rivista]
L., Marcheselli; G., Pistoni; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
The static dielectric constant (epsilon) has been measured at 2 MHz for N,N-dimethylformamide (1), 1,2-dimethoxyethane (2), and their nine binary mixtures covering the whole miscibility field (0 less-than-or-equal-to x1 less-than-or-equal-to 1) in the 40-80-degrees-C temperature range. The experimental epsilon values were fitted by empirical equations of the types epsilon = epsilon(T), epsilon = epsilon(x1), and epsilon = epsilon(T,x1). The mixing quantity deltaepsilon has been evaluated and fitted by a Redlich-Kister equation. The trend of deltaepsilon vs mole fraction curves shows negative deviations from ideality, and makes evident the presence of a stable dipolar interaction between unlike molecules.
1993
- THE RELATIVE PERMITTIVITY OF 1,2-DIMETHOXYETHANE WATER SOLVENT MIXTURES FROM -10 TO 80-DEGREES-C
[Articolo su rivista]
L., Marcheselli; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
Relative permittivities (epsilon) and the excess property (epsilon(E)) for the binary mixtures formed by 1,2-dimethoxyethane with water have been measured at various temperatures in the range from -10 to +80-degrees-C. These mixtures have interesting properties for electroanalytical applications. Their study should help in understanding the phenomenology of cosolvency towards ionizable and inert solutes. The results of the epsilon(E) analysis are discussed in terms of the influence of interactions between the components, order and degree of packing in the mixtures, and any other structural effect which occurs in solution.
1993
- THE RELATIVE PERMITTIVITY OF 1,2-ETHANEDIOL PLUS 2-METHOXYETHANOL PLUS WATER TERNARY MIXTURES
[Articolo su rivista]
F., Casarini; L., Marcheselli; Marchetti, Andrea; Tassi, Lorenzo; G., Tosi
abstract
The relative permittivities epsilon for the ternary 1,2-ethanediol (component 1) + 2-methoxyethanol (2) + water (3) solvent system have been measured for 66 mixtures covering the whole mole fraction composition 0 less-than-or-equal-to X1/X2/X3 less-than-or-equal-to 1 range at -10, -5 and 0-degrees-C. The experimental data were used to test some empirical relations stating the dependence of epsilon = epsilon (X1, X2, X3). A comparison between the calculated and experimental data show that these equations can be usefully employed to predict epsilon values in correspondence of the experimental data gaps.
1993
- THERMODYNAMIC BEHAVIOR OF SOME ELECTROLYTES IN ETHANE-1,2-DIOL FROM-10 TO +80-DEGREES-C
[Articolo su rivista]
F., Corradini; L., Marcheselli; Tassi, Lorenzo; G., Tosi; S., Fanali
abstract
Conductivities of the electrolytes NaBr, NaPi, HPi, NaBPh4, and Ph4PBr in ethane- 1, 2-diol were determined in the - 10 less-than-or-equal-to t less-than-or-equal-to + 80-degrees-C temperature range. The experimental data were analyzed by the Fuoss-Hsia equation, which provides further informative parameters such as the dissociation constant (K) of the ion pairs formed in solution, the limiting equivalent conductivity (LAMBDA0), and the ion-size parameter (a). Thermodynamic behaviour of these electrolytes was derived from analysis of the K values. Single-ion conductivities were evaluated on the basis of the assumption of Ph4PBPh4 as reference electrolyte.
1993
- The ethane-1,2-diol / water solvent system : densities and excess molar volumes at various temperatures
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; L., Marcheselli; Tassi, Lorenzo; G., Tosi
abstract
Densities (rho) are presented for aqueous binary mixtures of ethane-1,2-diol at different mole fractions covering the whole miscibility field and at various temperatures (t) in the -10 less-than-or-equal-to t/degrees-C less-than-or-equal-to +80 range. The values of the excess molar volume (V(E)) are discussed in terms of: (i) the influence of interactions between the components; (ii) order and degree of packing in the pure species and in the mixtures; (iii) free volume differences.
1993
- Viscosities of 1,2-ethanediol - 2-methoxyethanol solvent mixtures at various temperatures
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
Viscosities were measured for binary solvent mixtures of 1,2-ethanediol-2-methoxyethanol at 19 temperatures ranging from -10 to 80 degrees C. Several different equations, such as those of Arrhenius, Waterton, and Williams et al., have been applied in order to establish the best regression fit for eta as a function of temperature. For this binary solvent system, the viscometric properties are continuous but not a linear function of the mixture composition. The deviations of the excess viscosities from ideality were found to be useful in detecting the formation of solvent-cosolvent complex species and to evaluate their stoichiometrical composition.
1993
- Viscosity data and viscous flow thermodynamics of 2-methoxyethanol + water binary mixtures
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Kinematic viscosities (v) have been measured for pure 2-methoxyethanol, pure water, and nine of their mixtures over the entire composition range and, where possible, at 19 temperatures ranging from -10 to +80-degrees-C. The above property was fitted by empirical equations stating its dependence on temperature (T) and mole fraction (XI) of the mixtures. The experimental data for the binary mixtures were used to test the validity of mixing rules at different temperatures.
1992
- Densities and excess molar volumes of 2-methoxyethanol / water binary mixtures
[Articolo su rivista]
F., Corradini; Franchini, Giancarlo; L., Marcheselli; Tassi, Lorenzo; G., Tosi
abstract
Densities (rho) are reported for the 2-methoxyethanol (component 1)/water (component 2) solvent system, over the full composition range (0 less-than-or-equal-to X1 less-than-or-equal-to 1) at temperatures (t) from -10 to +80-degrees-C. The experimental data have been fitted by three empirical relations that represent the functions rho = rho(t), rho = rho(X1), rho = rho(t, Xi), and the excess volume values by a Redlich-Kister equation. The 1:2 2-methoxyethanol/water adduct appears to be stable throughout the temperature range.
1992
- Dielectric behaviour of the 2-methoxyethanol-1,2-dimethoxyethane solvent system
[Working paper]
Goldoni, G.; Marcheselli, L.; Pistoni, G.; Tassi, L.; Fanali, S.
abstract
The static relative permittivity at various temperatures ranging from -10 to +80°C has been measured for 2-methoxyethanol, 1,2-dimethoxyethane and nine mixtures covering the whole miscibility field expressed by the mole fraction of 2-methoxyethanol (0 ≤ X1 ≤ 1). Equations describing the dependence of the relative permittivity on temperature [ε = ε(T)], and binary composition [ε = ε(X1)], have been checked. Furthermore, a single function ε = ε(T, X1) has been obtained by combining the previously cited monovariant equations. As a rule, the calculated values agree very well with the experimental ones. The excess extrathermodynamic parameter εE, which provides much useful information about the possibility of forming solvent-cosolvent complexes is briefly discussed. This fact has been interpreted on the basis of specific interactions of any kind between different molecules, taking into account geometric effects and steric hindrances.
1992
- Dissociation constants of picric acid in mixtures of N,N-dimethylformamide + ethane-1,2-diol
[Articolo su rivista]
F., Corradini; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The acid dissociation constants of 2,4,6-trinitrophenol (picric acid) were determined in N,N-dimethylformamide and ethane-1,2-diol from -10 to +80-degrees-C and in two N,N-dimethylformamide + ethane-1,2-diol mixtures from +20 to +80-degrees-C using the conductometric method. The experimental conductivity data were analyzed by means of the Fuoss-Hsla equation, and the dissociation constants were fitted by the integrated Van't Hoff equation.
1992
- N,N-DIMETHYLFORMAMIDE-2-METHOXYETHANOL SOLVENT SYSTEM - DENSITIES AND EXCESS MOLAR VOLUMES AT VARIOUS TEMPERATURES
[Articolo su rivista]
Marcheselli, Luigi; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Densities (rho) have been measured for N,N-dimethylformamide (1), 2-methoxyethanol (2), and for nine binary mixtures covering the whole miscibility field (0 less-than-or-equal-to X1 less-than-or-equal-to 1) in the temperature range - 10- + 80-degrees-C. The experimental data were used to test some empirical equations of the type rho = rho(t), rho = rho(X1) and rho = rho(t, X1). Furthermore, the excess volumes (V(E)) for these binaries have been examined and discussed at all the investigated temperatures in terms of the influence of interactions between unlike molecules. The V(E) vs. X1 plots suggest the presence of some stable adducts, having N,N-dimethylformamide: 2-methoxyethanol stoichiometric ratios of 1 : 2 and 1 : 1 depending on the temperature.
1992
- Relative Permittivity of 1,2-Ethanediol + 1,2-Dimethoxyethane from -10 to +30 °C
[Working paper]
Goldoni, G.; Maffei, E.; Marcheselli, L.; Tassi, L.
abstract
The relative permittivities (ϵ) of 1,2-ethanediol, 1,2-dimethoxyethane, and nine binary mixtures were measured at five temperatures from -10 to +30 °C. The experimental data were fitted vs composition of the mixture (x1) in order to investigate the existence of solvent/cosolvont complexes, their stoichiometric ratios, and their thermostability. The formation of these complex species may be interpreted on the basis of specific interactions between the components of the mixed solvents. © 1992, American Chemical Society. All rights reserved.
1992
- SYNTHESIS AND CHARACTERIZATION OF LANTHANIDE COMPLEXES - LANTHANUM(III), CERIUM(III) AND EUROPIUM(III) DERIVATIVES WITH PARA-SUBSTITUTED AND META-SUBSTITUTED BENZENESELENINIC ACIDS
[Articolo su rivista]
G., Graziosi; Marchetti, Andrea; Preti, Carlo; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
New complexes of lanthanum(III), cerium(III) and europium(III) with para- and meta-substituted benzeneseleninic acids of the type XC6H4SeO2H (X = H, m-Cl, p-Br, p-Me) are reported. The compounds Ln(XC6H4SeO2)3, Ln(XC6H4SeO2)2Cl, Ln(XC6H4SeO2)Cl2 and Ln2(XC6H4SeO2)3Cl3, where Ln denotes trivalent La, Ce, and Eu, have been studied using spectroscopic techniques (ir, far-ir and electronic spectra), magnetic susceptibility, thermogravimetric and conductivity measurements. The electronic spectra of the 1 : 3 derivatives have been analysed and spectral parameters are calculated and discussed for the europium complexes. The ir data point to a seleninato-O,O' coordination for all the complexes; in particular, the presence of three SeO bands with irreducible representation A 2 + 2E in the ir spectra of the tris derivatives suggests an octahedral configuration with D 3 symmetry. All the halo derivatives are polymeric and octahedral in nature with bridging halide atoms. The magnetic moment values lie in the expected ranges and show very little deviation from Van Vleck values.
1992
- Static dielectric constant of N,N-dimethylformamide / 2-methoxyethanol solvent system at various temperatures
[Articolo su rivista]
F., Corradini; L., Marcheselli; Tassi, Lorenzo; G., Tosi
abstract
Measurements of static dielectric constants (epsilon) have been made for binary liquid mixtures of N,N-dimethylformamide (DMF)/2-methoxyethanol (ME) at 19 temperatures ranging from -10 to + 80-degrees-C. Some empirical equations of the type epsilon = epsilon(T), epsilon = E(X1), and epsilon = epsilon(T,X1) have been applied to check their validity. The epsilon(E) values, which refer to the deviation of the dielectric constants of the binaries from the values arising from mole fraction mixture law, have been calculated. Deviations from ideal behaviour have been found to be positive at all temperatures. The positive epsilon(E) values are attributed to a specific interaction between unlike molecules, which leads to the formation of complexes between DMF and ME in the liquid state. These nDMF . mME complex moieties were found to have the stoichiometric ratios 2:1, 1:1, and 1:2 in the temperature range of -10 to + 80-degrees-C.
1992
- The Relative Permittivity of N,N-Dimethylformamide/1,2-Dimethoxyethane Binary Mixtures from -10 to 40 C
[Articolo su rivista]
Goldoni, Gianni; Marcheselli, Luigi; Marchetti, Andrea; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Binary solutions of N,N-dimethylformamide and 1,2-dimethoxyethane have been investigated by means of dielectric measurements at temperatures ranging from −10 to +40°C, and for nine mixtures covering the whole miscibility field expressed by the mole fraction of one component (0≤X1≤1). The experimental data were used to study the dependence of ɛ on T and X1, of the type ɛ = ɛ(T), ɛ = ɛ(X1), and ɛ = ɛ(T,X1). Further, the excess mixing function ɛE has been evaluated in order to identify particular patterns of interaction between unlike molecules and any other factor that could modify such patterns. The minimum in the ɛE vs. composition plots suggests the formation of an adduct of stoichiometric ratio DMF∶DME=1∶1 at all the investigated temperatures.
1992
- Titrimetric behaviour of picric acid in mixed 2-methoxyethanol/water solvent system
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The titrimetric behaviour of picric acid in pure 2-methoxyethanol, in pure water and in many of their binary mixtures has been investigated by using the conductometric method and 1,1,3,3-tetramethylguanidine as titrant base. The study has been carried out working at 0, 25, 50 and 75-degrees-C and the effects of temperature and composition of the solvent mixture on the shape of the curves and on the accuracy of the analytical recovery have been pointed out. Previous observations on the hypothetical existence of a particular ''limiting mixture'' which separates the solvent system under study into two groups (0 less-than-or-equal-to X(water) < ''limiting mixture' and ''limiting mixture'' < X(water) less-than-or-equal-to 1, where X represents the mole fraction) have been confirmed and a stoichiometric composition for such a mixture, which depends on temperature, has been suggested.
1992
- Viscosities and activation energies of viscous flow of the 1,2-ethanediol / N,N-dimethylformamide binary solvent system
[Articolo su rivista]
F., Corradini; L., Marcheselli; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
Densities (rho) and absolute viscosities (eta) of pure 1,2-ethanediol, NN-dimethylformamide and of their nine mixtures were determined at nineteen temperatures ranging between -10 and +80-degrees-C. The above properties were fitted by empirical equations stating their dependence on temperature and composition of the mixtures. The extrathermodynamic excess functions, such as the excess rheochor [R(E)] and the excess Gibbs energy of activation of viscous flow DELTA-G(E), have been studied. The trend of [R(E)] vs. composition of the mixtures shows negative deviations from ideality, indicating extensive molecular interactions between the components of the binary solvent system. Furthermore, activation enthalpies and entropies for viscous flow have been obtained and their variations with composition have also been discussed.
1991
- CRYSTAL-STRUCTURE OF N,N'-DIPHENYL-GUANIDINIUM M-CHLOROBENZENESELENINATE
[Articolo su rivista]
Antolini, Luciano; Marchetti, Andrea; Preti, Carlo; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The synthesis, and crystal and molecular structure of N,N'-diphenylguanidinium m-chlorobenzeneseleninate (C19H18ClN3O2Se), M(r) 434.78, are reported. The crystal lattice of the compound belongs to the monoclinic space group P2(1)/c with a 7.277(1), b 12-793(2), c 20.013(4) angstrom, beta-94.733(12)-degrees, V 1859.8 angstrom3, Z 4, D(obs) 1. 53 (by flotation), D(calc) 1.555 g cm-3, lambda(Mo K-alpha) 0.71069 angstrom, mu-21.0 cm-1, F(000) 880, T 293 K, R 0.057 and R(w) 0.059 for 1745 unique observed reflections with I > 2.0-sigma(I). The crystal packing consists of parallel layers of anions intercalated with cations interacting through electrostatic contacts. Vibrational spectra have been also recorded, and are discussed.
1991
- Density and excess molar volumes of the 1,2-ethanediol + 2-methoxyethanol solvent system at various temperatures
[Articolo su rivista]
Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Densities are reported for the binary mixture 1,2-ethanediol + 2-methoxyethanol in the whole composition range at 19 temperatures between -10 and +80-degrees-C. The excess molar volumes, V(E), calculated from the density values, are negative at all concentrations and become more negative with increasing temperature.
1991
- Dissociation equilibria of picric acid in the binary N,N-dimethylformamide / 2-methoxyethanol solvent system
[Articolo su rivista]
Marchetti, Andrea; Preti, Carlo; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Three empirical equations are proposed to fit the experimental values of the dissociation constant for picric acid, chosen as guide-solute working in the N,N-dimethylformamide/2-methoxyethanol solvent system. The work was performed operating at 19 temperatures ranging from - 10 to + 80-degrees-C in the pure solvents and in their nine mixtures, identified by the mole fraction (X) of one component. This empirical treatment, which describes the dependence of the dissociation constant on temperature and composition of the solvent mixture, is represented by functions of the type K = K(T), K = K(X), and K = K(T, X). The K = K(T, X) equation in its complete form is composed of 20 terms, some of which can be eliminated because of small statistical weight; the number and type of these terms vary on passing from one solvent system to another and the best-fitting form is suggested. A comparison among various K = K(T, X) equations proposed in the present and in previous works has been made.
1991
- Ethane-1,2-diol - 2-methoxyethanol solvent system. Dependence of the relative permittivity and refractive index on the temperature and composition of the binary mixture
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The extrathermodynamic parameters, relative permittivity (epsilon-r) and refractive index (n), have been measured for ethane-1,2-diol-2-methoxyethanol binary mixtures over the entire composition range, at various temperatures ranging between - 10 and 80-degrees-C. For this system, as far as for many solvent-cosolvent systems which are useful for analytical and electrochemical applications, the properties cited above are continuous but not linear functions of the binary composition. Various equations have been applied in order to establish the best regression models for the relationship y = f(X), where X is the composition of the mixture. On the whole, minima occurred in the excess function (epsilon-E), showing the existence of various solvent-cosolvent complexes of different stoichiometric ratios (2:1, 1:1 or 1:2) and of different thermostabilities, which may be interpreted in terms of moderate interactions such as dipolarity, polarizability and hydrogen bonding between the mixed solvents. Among the above complexes, the ethane-1,2-diol-2-methoxyethanol 1:2 adduct is suggested to be the true 'limiting mixture', on the borderline between the types of behaviour typical of the two pure solvents. Furthermore, empirical patterns in the refractive index were used to scrutinize the most important mixing rules in order to determine the properties of the mixture on the basis of those of its pure components.
1991
- The N,N-dimethylformamide + ethane-1,2-diol solvent system. Dielectric constant, refractive index, and related properties at various temperatures
[Articolo su rivista]
Marchetti, Andrea; Preti, Carlo; M., Tagliazucchi; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Dielectric constant (epsilon) and refractive indexes (n) were measured for pure N,N-dimethylformamide, ethane-1,2-diol, and their six mixtures over the entire composition range and, where possible, at nineteen selected temperatures ranging between -10 and +80-degrees-C. The above properties were fitted by empirical equations stating their dependence on temperature (T) and mole fraction (x1) of the mixture. The refractive indexes of the binary mixtures were used to test the validity of mixing rules at different temperatures.
1991
- The N,N-dimethylformamide / ethane-1,2-diol solvent system. Density, viscosity and excess molar volume at various temperatures
[Articolo su rivista]
Marchetti, Andrea; C., Preti; M., Tagliazucchi; Tassi, Lorenzo; G., Tosi
abstract
Density (rho), kinematic viscosity (nu), and absolute viscosity (eta) are presented for mixtures of ethane-1,2-diol and N,N-dimethylformamide from -10 to +80-degrees-C. The above properties were fitted by empirical equations stating their dependence on temperature and mole fraction of the mixture. Furthermore, some considerations regarding the meaning of the obtained adjustment parameters are made. The excess functions, such as molar volumes V(E), have been derived. The trends of V(E) data vs mole fraction of the mixtures have exhibited markedly negative deviations from ideality, indicating extensive molecular interactions between the components of the binary solvent system.
1990
- Ionization and Dissociation of Weak Electrolytes. An Initial Approach to Kd and Ki Evaluation.
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The experimental dissociation constant K of weak electrolytes may be consldered as derlved from dlfferent contributions due to the Ionization, K,,and dlssociation, Kd,equlllbrla, respec- tively. AsimplemethodforK,andKdevaluatlonisherein proposed, startlng from experimental K data, obtained by the conductometric method, for plcrlc acld in a set of binary solventsystemmixturesattemperaturesrangingfrom-10 to +80 O C . The correlatlonsbetweenK,and Tand betweenK, and Tare moreover suggested on the basis of a general ex- pression derlved from the Integrated Van’t Hoff equation.
1989
- An Approach to the Problem of the Dependence of the Dissociation Constant of Weak Electrolytes on the Temperature and the Solvent Composition in the Ethane-1,2-diol / 2-Methoxyethanol Solvent System.
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; Preti, Carlo; Tassi, Lorenzo; Tosi, Giuseppe
abstract
This empirical approach to clarify the problem of the dependence of the dissociation constants of weak electrolytes on temperature and composition of mixed solvents systems (X) is applied to the dissociation constant of picric acid in ethane-1,2-diol, in 2-methoxyethanol and in their binary mixtures. The data utilized here are those of previous work (recalculated by means of the more accurate Fuoss–Hsia equation) integrated by the experimental data relative to three new mixtures. Two equations of the dependence of K on T and of K on X, respectively, are suggested and good accordance between experimental and calculated values is shown. Starting from the two above-mentioned equations, general empirical equations for the surface K(T, X) are proposed; the average difference between calculated and experimental K values is ca. 8 %. A three-dimensional plot of the function K=K(T, X) is presented. The proposed empirical models are compared to that obtained for the previously studied ethane-1,2-diol–water solvent system and advantages and limitations of the models are discussed.
1989
- Conductometric Titration of Poliprotic Acids in non Aqueous Mixed Solvents. Effects of Temperature and Composition of the Solvent Mixture.
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; Preti, Carlo; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The effects of temperature and composltlon of the solvent mixtures on the shape and on the analytical recoveries of conductometric tltratlons of polyprotlc aclds were studled for the solvent system 2-methoxyethanol/ethane-1,2-diol operating at -10, 25, 50, and 75 °C. The experimental evidence indicates that the N- or chair-shape of the tltratlon curves depends on the solvent physicochemical propertles, on the temperature, and on the acld solute to be tltrated; in particular the Influence of the distance between the carboxylic groups Is discussed. Titrations performed In 2-methoxyethanoi are associated in general wlth N-shaped curves, which however turn to chalr-shaped as the temperature Increases. Ethane-1,2-diol always produces chair-shaped curves as a consequenceof its more dlssoclating ability toward the tltratlonformed adducts. The study of the tltrations of phthalic acld In some mixtures of the above solvents exhibited behaviors consistent wlth previous observations regarding the exlstence of a partlcuiar “limiting mlxture” whlch separates the solvent system under study Into two well-defined groups (0 Ix . ~< “~limiting mixture” and “limiting mixture”
1989
- Ionic Equilibria of Picric Acid in Mixed Anphiprotic Solvents.The 2-Methoxyethanol/Water Solvent System.
[Articolo su rivista]
Marchetti, Andrea; E., Picchioni; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Picric acld Is the gulde solute used In our studies In order to verify the applicability of an emplrikal treatment that descrlbes the dependence of the dlssoclatlon constant on temperature and composltlon of the solvent mlxture ( x Is mole fractlon).The 2-methoxyethano/water solvent system has been employed In thls work operatlng at 19 temperatures ranging from -10 to +80 °C; by use of the conductometric method the dissociation constant values of plcrlc acld have been evaluated by the Fuoss-Hsla equation. The data have been fltted by three emplrlcal equations that represent the functlons K = K(T), K = K ( x ) , and K = K(T,x). The K = K(T,x) equatlon In Its complete form Is composed of 20 terms, someof whkh can be elhnlnated because of small statistkal weigt; the number and type of these terms vary on passlng from one solvent system to another, and the best-flttlng form, which In thls case represents 13 terms, Is suggested. The posslblllty of extrapolatlng K values of plcrk acM In a pure water solutlon Is lnvestlgated and compared wlth similar previous calculatlons.
1988
- Effects of temperature and solvent composition on conductometric titrations in non aqueous mixed solvents
[Articolo su rivista]
Franchini, Giancarlo; Preti, Carlo; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The effects of temperature and composition of solvent mixtures on conductometric tltratbns have been lnvestlgated for the solvent system 2methoxyethand / ethane-l,2dloi. Good analytical results were obtained for a series of monocarboxylic aiiphatk and ammatk aclds and phenols by uslng 0.10 M N,N'-dlphenylguanMlne as standard titrant. Conductance titration curves, performed at -10, 25, 50, and 75 O C in the abovementioned pure solvents and in their four binarymixtures, are plesented and discussed. The peculiar behavlor of pick ackl in the lnvestlgated solvent system is emphasized in the discusslon.
1988
- Preparation, properties and reactivity of gold complexes with some heterocyclic dithiocarbamates as ligands
[Articolo su rivista]
Forghieri, F.; Preti, C.; Tassi, Lorenzo; Tosi, G.
abstract
The syntheses, properties and reactivity of the gold complexes AuRdtc, Au(RdtC)3, Au(Rdtc)2X and Au(RdtC)X2 (X = Cl, Br; Rdtc = piperidine-, morpholine-, thiomorpholine-, piperazine-, N-methylpiperazine-, N-phenylpiperazine- and 4-phenyl-piperidinedithiocarbamate) are reported. Elemental analysis, electrical conductance measurements, spectral (electronic and IR), magnetic susceptibility and thermogravimetric studies were used for characterization. The dithiocarbamato ligands exhibit both bidentate behaviour acting as S,S′-donors and monodentate behaviour acting as S-donors, depending on the type of the complex. The diamagnetic behaviour confirms the low-spin d8 configuration for Au(III) complexes and some metal-ligand and metal-halide stretches have been assigned.
1988
- The Ethane-1,2-diol/Water Solvent System. The Dependence of the Dissociation Constant of Picric Acid on the Temperature and Composition of the Solvent Mixture.
[Articolo su rivista]
Franchini, Giancarlo; Marchetti, Andrea; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The dissociation constants of 2,4,6-trinitrophenol (picric acid) in a set of ethane-1,2-diol–water mixtures have been determined by the conductometric method at temperatures ranging from –10 to 80 °C. The experimental k values exhibit a regular trend, with a relative maximum in the investigated temperature range for all the binary solvent systems, and they are well fitted by an equation of the type ln K=a0+a1T+a2/T+a3 ln T. In order to verify the reliability of Kmax values, a series of correlations was made, on the basis of the above equation, of Harned's theory and of a pKvs. 1/ε plot; all the methods provide results consistent with each other. Furthermore, two empirical equations for the functions K=K(χ) and K=K(T,χ) are proposed in order to try to predict the K values of the studied solute over the whole variation of the investigated T and χ. Both these model equations allow us to extrapolate the K values of picric acid in pure water solution, in which conductometric and potentiometric methods are unable to give consistent values.
1987
- A conductometric study of dissociation of picric acid in 2-methoxyethanol and 1,2-ethanediol from -10 to 80°C
[Articolo su rivista]
Franchini, Giancarlo; Ori, E.; Preti, Carlo; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Dissociation constants of 2,4,6-trinitrophenol (picric acid) in 2-methoxyethanol and 1,2-ethanediol were measured by a conductancemethod at temperatures ranging from - 10 to 80°C. The determined constants in the two solvents are discussed andare compared on the basis of the physical properties of the solvents, which have been measured at the various temperatures. Thedissociation constants show different behaviour with the temperature in the investigated range and they are fitted by equationsof the type In K = A+BT+C/T+D In T. Furthermore, the thermodynamic functions have been evaluated and discussed
1987
- Dithiocarbamate complexes of rhodium (III), iridium (III), palladium (II) and platinum (II)
[Articolo su rivista]
A. C., Fabretti; C., Preti; Tassi, Lorenzo; G., Tosi; Zannini, Paolo
abstract
We report the preparation and characterization of the complexes of rhodium(III), iridium(III), palladium(II) and platinum(II) with the following ligands: Pzdtc, N-MePzdtc, N-PhPzdtc, Pipdtc, 4- PhPipdtc, Morphdtc, Timdtc, and with their methyl esters.The dithio ligands act as bidentate S,S′-donors in all the new derivatives. From the electronic absorption spectra the values of the ligand field parameters were determined. The nephelauxetic parameters are indicative of a strong covalency in the metal-ligand bond. All the compounds reported here are diamagnetic.
1987
- The ethane-1,2-diol - 2-methoxyethanol solvent system. The dependence of the dissociation constant of picric acid on the temperature and composition of the solvent mixture
[Articolo su rivista]
Franchini, Giancarlo; Tassi, Lorenzo; G., Tosi
abstract
The ethane-1,2-diol - 2-methoxyethanol solvent system. The dependence of the dissociation constant of picric acid on the temperature and composition of the solvent mixture
1986
- Magnetic and spectroscopic studies on copper(II) and chromium(III) complexes with sulfur chelating ligands
[Articolo su rivista]
Ac, Fabretti; C., Preti; Tassi, Lorenzo; G., Tosi; Zannini, Paolo
abstract
A number of complexes of chromium(III) and copper(II) with heterocyclic dithiocarbamate ligands is reported. The newly prepared compounds are characterized on the basis of near- i.r . and far- i.r . spectroscopy, electronic and e.p.r . spectra, conductivity measurements and magnetic moment studies at different temperatures. The dithio ligands exhibit bidentate behaviour acting as S,S′-donors in all the complexes. The chromium(III) compounds have g values in the 1.991-1.999 range and nephelauxetic parameters indicative of an appreciable metal- ligand covalency. The e.p.r . data of the copper(II) derivatives provide parameters typical of sulfur coordination in planar CuS4 chromophores ; the α bonding parameters are indicative of strongly covalent metal- ligand interactions.
1985
- A mass spectral investigation of 4-phenylpiperidine and N-phenylpiperidine-carbodithioato sodium salts and their cobalt (II), nickel (II) and copper (II) complexes
[Articolo su rivista]
A., Benedetti; C., Preti; Tassi, Lorenzo; G., Tosi; Zannini, Paolo
abstract
Two new dithiocarbamate ligands and their cobalt(II), nickel(II)_and copper(II) complexes have been investigated by mass spectrometry. The fragmentation modes of the ligands have been discussed and compared with those of previously studied dithioligands and with those of the obtained complexes. An important feature of the spectra of the ligands is the absence of the molecular ion peaks which were present in the spectra of the previously studied dithioligands; however, the molecular ion peaks are present in the spectra of the complexes reported here. This behaviour is exactly the reverse of that observed in our previous studies. The postulated decomposition routes of the ligands and of the complexes are discussed in detail.
1985
- Coordinating ability of methylpiperidine dithiocarbamates toward platinum group metals
[Articolo su rivista]
Franchini, Giancarlo; A., Giusti; C., Preti; Tassi, Lorenzo; Zannini, Paolo; G., Tosi
abstract
Coordinating ability of methylpiperidine dithiocarbamates toward platinum group metals
1985
- Silver and gold complexes with cyclic carbodithioates as ligands
[Articolo su rivista]
Ac, Fabretti; A., Giusti; C., Preti; Tassi, Lorenzo; Zannini, Paolo
abstract
The preparation and magnetic susceptibility, electronic, infrared, electrical conductivity and thermogravimetric studies of a series of monomethylsubstituted piperidine dithiocarbamates of silver(I), gold(I) and gold(III) are reported. The complexes are formulated as AgRdtc, AuRdtc, Au(Rdtc)3. Au(Rdtc)2X and AuRdtcX2 (X=Cl, Br). The dithioligands exhibit both bidentate behaviour acting as S,S ' -donors and monodentate behaviour acting as S-donors, depending on the type of the complex. The diamagnetic behaviour of the gold(III) derivatives is in accord with the usual low-spin d8 configuration. The metal-sulphur and metal-halide stretches have also been assigned and are in accord with the proposed structures. The molecular weight determinations indicate monomeric structures for the Au(Rdtc)3 and AuRdtcX2 complexes and dimeric structures for the Au(Rdtc)2X derivatives. The results of the spectroscopic studies indicate that in the Au(Rdtc)3 complexes one of the dithiocarbamate groups must act as a bidentate ligand, while the other two act as monodentates giving square planar structures.
1985
- The conductometric titration of cholic acids in non-aqueous solvents
[Articolo su rivista]
Preti, Carlo; Tassi, Lorenzo; Tosi, Giuseppe
abstract
The study is related to the feasibility of conductometric titrations of cholic acids in non-aqueous solvents (2-methoxyethanol, and 1,2-ethanediol), using N,N-diphenylguanidine as titrant base solubilized in the same solvent.
1983
- Conductometric titrations of phenols and carboxylic acid mixtures in 2-methoxyethanol
[Articolo su rivista]
NEVIANI GILIBERTI, E.; Preti, Carlo; Tassi, Lorenzo; Tosi, Giuseppe
abstract
Acid-base equilibria have been studied by conductometric titrations of phenols and carboxylic acid mixtures in 2-methoxyethanol.
1983
- Coordination chemistry of cycloserine derivatives. Complexes of iron (II), iron (III), manganese (II) and palladium (II) with N4, N4 –tereftal-bis(cycloserine)
[Articolo su rivista]
C., Preti; Tassi, Lorenzo; G., Tosi; Zannini, Paolo; Af, Zanoli
abstract
Synthetic and other studies of iron(II), iron(III), manganese(II) and palladium(II) complexes with the cycloserine derivative, N4, N ' 4-tereftal-bis(cycloserine) or Terizidone, are reported. The methods used for the characterization of the compounds include elemental analyses, molar conductance, magnetic moments, electronic and infrared spectroscopy and thermal analyses (TG and DTG). From the magnetic properties it was concluded that the above ligand forms low-spin complexes with palladium(II) and high-spin complexes with iron(II), iron(III) and manganese(II). The wavelengths of the principal absorption bands have been accounted for quantitatively in terms of the crystal field theory for manganese(II) and tetrahedral iron(III) complexes. The values of B and C in the iron(III) derivatives are less than in the corresponding manganese(II) complexes. Far-infrared spectra have been extensively studied and the relationship between metal-halogen stretching vibrations and stereochemistry of the complexes is outlined and shown to have potential application in the assignment of the stereochemistry and coordination number of these new metal-halide complexes. The ligand is always monodentate N-bonded through the nitrogen of the imino group of the isoxazole ring. Under our experimental conditions no metal-induced cycloserine ring opening was observed.
1983
- Synthesis and characterization of ruthenium(III) complexes with para-and meta-substituted benzenseleninic acids as ligands
[Articolo su rivista]
Preti, C; Tassi, Lorenzo; Tosi, G.
abstract
A number of complexes of ruthenium(III) with para- and meta-substituted benzeneseleninic acids, XC6H4SeO2H (X = H, m-Br, p-Br, p-CH3, m-Cl, p-Cl) are reported. The recently prepared compounds are characterized through elemental analyses, near and far i.r. spectroscopy, electronic spectra, conductivity measurements, thermal analyses (TG and DTG) and magnetic susceptibility measurements. The wavelengths of the principal electronic absorption peaks have been accounted for quantitatively in terms of the crystal field theory; the nephelauxetic parameters are all indicative of an appreciable metal-ligand covalency. The i.r. results point to a O, O′-seleninato coordination for all the complexes; in particular the presence of three SeO bands with the irreducible representation A2 + 2E in the i.r. spectra of the trisderivatives of the type Ru (XC6H4SeO2)3 suggests an octahedral configuration with D3 symmetry. The complexes of the type Ru (XC6H4SeO2)2 Y (Y = Cl, Br) are polymeric octahedral with bridging halides.
1982
- Cycloserine derivatives as ligands. The coordination ability of 4,4’-[1,4-phenylenebis(methylidynenitrilo)bis(isoxazolidin-3-one)] towards chromium (III), ruthenium (III) and rhodium (III) halides
[Articolo su rivista]
C., Preti; Tassi, Lorenzo; G., Tosi; Zannini, Paolo; Af, Zanoli
abstract
The complexes of the cycloserine derivative, 4,4'-[1,4-phenylenebis(methylidynenitrilo)]bis(isoxazolidin-3-one) or terizidone, with chromium(III), ruthenium(III) and rhodium(III) have been synthetized; their structures have been suggested on the basis of analytical, conductivity, spectral (visible, infrared and far-infrared) and magnetic data, and the thermal analyses have revealed the extent of coordinated water among the chromium and ruthenium complexes. The various ligand field parameters have been evaluated; the B' values suggest a strong covalency in the metal-ligand σ bond and the Dq values show a medium-strong ligand field. The position and multiplicity of the metal-halogen stretching modes in the far-infrared region have been extensively investigated and discussed; the results are particularly useful in distinguishing between the mer- and fac-isomers in the octahedral compounds of the ML3X3 type. The ligand is monodentate O-bonded or N-bonded through the oxygen of the keto group or through the nitrogen of the imino group of the isoxazole ring. We have never observed a metal-induced cycloserine ring opening under the present experimental conditions.
1982
- The first example of a copper(II) chloride complex with 1,3-thiazolidine-2-thione
[Articolo su rivista]
Ac, Fabretti; M., Ferrari; Franchini, Giancarlo; C., Preti; Tassi, Lorenzo; G., Tosi
abstract
complessi di metalli di transizione
1982
- mass spectral investigations on selenium compounds. *
[Articolo su rivista]
Benedetti, A.; Preti, C.; Tassi, Lorenzo; Tosi, G.
abstract
Substituted benzeneseleninic acids of the type XC6H4SeO2H (X = m-Cl, p-Cl, m-Br, p-Br, p-Me, m-NO2, p-NO2) have been investigated by mass spectrometry. The fragmentation modes and the fragment ions are discussed and compared with those obtained from the mass spectrum of m-nitro-phenyl selenocyanate, O2NC6H4SeCN. Generally, as regards the acids, besides very weak peaks due to the molecular ions, a number of peaks at higher mass numbers and of greater intensity is observed; these peaks are in multiplets typical of the presence of two selenium atoms, and they correspond to the disubstituted diphenyl diselenides of the type XC6H4SeSeC6H4X. m-Nitrophenyl selenocyanate shows an intense molecular ion peak and the relative fragmentation, while the peak due to the diselenide is of very low intensity.
1982
- resolution of mixtures of organic acids by conductometric titrations in 2-methoxyethanol
[Articolo su rivista]
Preti, C.; Tassi, Lorenzo; Tosi, G.
abstract
A study has been made on the conductometric titrations of mixtures of organic acids in 2-methoxyethanol as solvent and with 0.01 M DPG as standard titrant. Conductometric titration curves are pèresented and discussed for both aliphatic and aromatic mono- and dicarboxylic acids, and para- and meta-substituted benzenseleninic acids in binary, ternary, and quaternary mixtures. The solvent is suitable for the resolution of acid mixtures in some cases where a quantitative determination is impossible in aqueous solutions owing to very close pK values.