1,721,138 research outputs found
Ionic association of alkali-metal bromides in 2-methoxyethanol
No full textConductance 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.Conductance data are reported for alkali-metal bromides MBr (M = Li, Na, K, Rb, Cs), NaBPh4 and Ph4PBr in 2-methoxyethanol at 19 temperatures in the -10 ≤ t/°C ≤ 80 range. The experimental data were processed by the Fuoss-Hsia equation which provides the dissociation constant (K), the limiting equivalent conductivity (Λ0), and the ion-size fitting parameter (å). 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
Relative permittivity analysis of N,N-dimethylformamide plus 1,2-dichloroethane binary mixtures
No full textThe 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
Kinematic viscosity and viscous flow in binary mixtures containing ethane-1,2-diol
No full textIt 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]
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)
No full textL’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
Density and volumetric behavior of 1,2-dimethoxyethane plus water binary mixtures from -10 to 80 degrees C
No full textThe 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
Density and excess molar volumes of binary mixtures of 1,2-dichloroethane plus 2-chloroethanol from -10 to 80 degrees C
No full textDensities (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
Recupero di principi bioattivi da prodotti secondari di lavorazioni agro-alimentari
No full textLa 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
resolution of mixtures of organic acids by conductometric titrations in 2-methoxyethanol
No full textA 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
L`Aceto Balsamico e la Tradizione Scientifica
No full textL'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
Processo per l’estrazione e purificazione di frazioni polifenoliche da prodotti secondari delle lavorazioni agro-alimentari zuccheriere
No full textLa 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
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