Effect of Electrostatic Interactions on the Vapor-Liquid Equilibrium Representation in Mixed Solvent/Electrolyte Systems

Abstract

This work considers the calculation of the effect of the electrolyte on the vapor-liquid equilibrium (VLE) of mixed solvent systems at different salt concentrations and at atmospheric pressure in order to evidence the influence of the electrostatic term on the VLE representation. Two modified UNIQUAC models (Sander et al., 1986 andMacedo et al., 1990), which take into account the long-range electrostatic interactions using different types of the Debye-Hückel term, are used. The calculations are based on the complete experimental data (VLE and salt solubility). The long-range term, although important in the representation of electrostatic interaction forces, is shown to have rather little effect on the representation of the solvents, practically nonsignificant at low salt concentrations.