Simultaneous estimation of excess enthalpy, excess Gibbs energy and vapor-liquid equilibrium using the modified Wilson model

A modified Wilson equation proposed in our previous paper [1] successfully improved the correlation of ternary liquid-liquid equilibrium, especially for Type I partially miscible mixtures. In this paper we attempt to extend the application of this modified model to simultaneously correlate thermodynamic properties of excess enthalpy, h(E), and excess Gibbs free energy, g(E), and vapor-liquid equilibrium. We collected data for more than one isotherm for h(E) and g(E) from the literature and simultaneously used these data to correlate the binary interaction parameters of the modified Wilson model. To accomplish this purpose, we further consider that the binary interaction parameters were temperature-dependent for our modified model. Two temperature-dependent forms, linear and non-linearly reciprocal, were assumed. The estimated interaction parameters taking into account these two considerations were then used to correlate binary isothermal properties of h(E) and g(E), and VLE, and binary isobaric VLE simultaneously. The calculated results were compared with the experimental data from the literature. No superiority between the two temperature-dependent functions was found, but both are slightly better than the Demirel-NRTL model [2] also simultaneously for estimating, h(E), g(E), and VLE.