Thermodynamic functions for the system ethanol+p-xylene from vapour pressures, enthalpies of mixing and volume of mixing, and their interpretation in terms of association

Abstract

Vapour pressure measurements for the system ethanol+p-xylene at 318.15 K are reported. The resulting activity coefficients are compared with those based on freezing-point depression measurements reported earlier. Enthalpies of mixing at 286.45, 308.15 and 318.15 K supplement the existing data. These permit the calculation of activity coefficients at 286.45, 298.15 and 308.15 K over the whole concentration range. The volume of mixing at 286.45 K is included for completion of the study on this system. The data are interpreted in terms of the association model evaluated for the ethanol + cyclohexane system, with an addition of a solvation equilibrium to allow for the interaction between the terminal hydroxyl group of the alcohol chains and a solvent molecule.