Vapour-liquid equilibrium and excess free energies for benzene + dioxan and carbon tetrachloride + dioxan systems

Abstract

This paper deals with the isothermal total vapour pressure measurements on the systems benzene + dioxan and carbon tetrachloride + dioxan in the temperature range of 22–40°C and over the whole composition range. The activity coefficients and the excess Gibbs free energies are evaluated at 25, 30 and 40°C. For both the systems the excess entropies are negative, suggesting an ordering in the solution due to a solute-solvent specific interaction. The excess free energies of complexing are calculated on the basis of an ideal associated solution model with species A, B, AB and AB2 in mutual equilibrium and using for reference, the excess free energies of the system cyclohexane + dioxan. The calculated excess free energies agree with the observed results.