Authors:E. Matteoli, L. Lepori, T. Usacheva, and V. Sharnin
The influence of H2O–EtOH and H2O–Acetone mixed solvents at various compositions on the thermodynamics of complex formation reaction between crown ether 18-crown-6
(18C6) and glycine (Gly) was studied. The standard thermodynamic parameters of the complex [Gly18C6] (log K°, ΔrH°, ΔrS°) were calculated from thermochemical data at 298.15 K obtained by titration calorimetry. The complex stability and its formation
enthalpy increase with increasing the non aqueous component concentration in both mixed solvents. The thermodynamic data were
discussed on the basis of the solvation thermodynamic approach and the solvation contributions of the reagents and of the
complex to the complex stability were analyzed.
Authors:B. Marongiu, Silvia Porcedda, D. Falconieri, Alessandra Piras, E. Matteoli, and L. Lepori
In this article are reported the excess enthalpies, HE, at 298.15 K, of liquid mixtures containing a linear mono-carboxylic acid (1) + di-n-butylether (2), determined by means of a titration calorimetric method. The experimental results, together with the literature data on thermodynamic properties of the above mentioned class of mixtures, have been interpreted in terms of the DISQUAC group contribution model. A set of structure-dependent interaction parameters, for the carboxylic group/oxygen contact, has been obtained. The model provides a fairly consistent description of the excess Gibbs energy, GE and excess enthalpy, HE, curves of the investigated mixtures.
Authors:Celia Duce, Maria Tinè, L. Lepori, E. Matteoli, B. Marongiu, and Alessandra Piras
Literature data on molar excess enthalpies and molar excess Gibbs energies, liquid-liquid equilibria, activity coefficients
at infinite dilution and partial molar enthalpies at infinite dilution of binary mixtures of n-perfluoroalkanes (C5−C8)+n-alkanes (C5−C8) and of n-perfluorohexane-linear monoethers of general formula, CH3(CH2)m-O-(CH2)n-CH3 (m,n=1–4), are treated in the framework of DISQUAC, an extended quasichemical group contribution theory. The systems are characterized
by two or three types of contact surfaces: aliphatic (CH3, CH2, CH and C groups), fluorine (F group) and oxygen (O group). Using a limited number of adjusted contact interchange energies
parameters, structure dependent, the model provides a fairly consistent description of the thermodynamic properties as a function
of concentration. The model may serve to predict missing data.
Authors:M. Angiuli, C. Ferrari, L. Lepori, E. Matteoli, G. Salvetti, E. Tombari, A. Banti, and N. Minnaja
Extra Virgin olive oils
(7 samples) originating from different areas of Tuscany, defective olive oils
(5 samples), commercial edible seed oils (4 samples) and two commercial samples
of olive oil (one declared ‘extra virgin olive oil’ and one ‘olive
oil’) were studied by different calorimetric techniques: high sensitivity
isothermal, differential scanning, and modulated scanning calorimetry. The
temperature interval (–60) – (+30)C was explored for monitoring: i) the main features of the liquid↔solid phase
transitions, ii) the nucleation and growth
rate of the polymorphous crystalline phases of the triacylglicerols, and iii) the melting process. This investigation was
planned for verifying the utility and effectiveness of calorimetry for screening
quality and origin of olive oil. To this end, the main calorimetric operation
modes have been applied, the experimental results reported and their utility
for developing an effective and reliable screening protocol discussed.