Thermodynamics of mixtures containing the CO and OH groups. I. Estimation of the DISQUAC interchange coefficients for 1-alkanol + n-alkanone systems

Abstract

1-Alkanol + n-alkanone mixtures are treated in terms of the DISQUAC group contribution model, reporting the interaction parameters for hydroxyl–carbonyl contacts. The quasichemical interchange coefficients are independent of the compounds in the mixture; the dispersive interchange coefficients depend on the intramolecular environment of the hydroxyl and (or) carbonyl groups. Mixtures of a given 1-alkanol with isomeric ketones are characterized by the same first dispersive interaction parameter, which is constant from 2-pentanone. This type of system, when including an alcohol up to 1-pentanol, needs different dispersive enthalpic parameters depending on the symmetry of the ketone. In this case, such parameters are constant from 2-pentanone or 3-pentanone. A detailed comparison is presented between DISQUAC results and data available in the literature on vapour–liquid equilibria, VLE (including azeotropic data), molar Gibbs energies, GE, molar excess enthalpies, HE, solid–liquid equilibria, SLE, natural logarithms of activity coefficients, In [Formula: see text] and partial molar excess enthalpies at infinite dilution,[Formula: see text]. For 54 systems, the mean relative standard deviation in pressure is 0.018; for 61 systems, this magnitude in the case of the HE is 0.059. It is noteworthy that the model yields good predictions over a very wide range of temperature for VLE and SLE. HE is also reasonably well represented at different temperatures. Larger discrepancies are encountered, as usual, for partial molar quantities at infinite dilution. Keywords: liquids, mixtures, thermodynamic properties, group contributions.