Isobaric Vapor−Liquid Equilibria for Water + Acetic Acid + Sodium Acetate

Abstract

Isobaric vapor−liquid equilibria for the binary water + sodium acetate and acetic acid + sodium acetate systems and ternary mixtures of water, acetic acid, and sodium acetate have been measured at 100 kPa with a recirculating still. The addition of sodium acetate to water + acetic acid mixtures produced an appreciable rise in equilibrium temperature but a small effect on the relative volatility of water, which was augmented at higher water solvent concentrations and decreased at lower concentrations. These effects increased with higher salt concentrations. The experimental binary data sets have been correlated using a modified Mock's electrolyte NRTL model, which takes into account the association of the acetic acid in the vapor phase by means of Marek's Chemical Theory (eNRTL−CT model). The estimated model parameters from binary data have been used to predict the ternary vapor−liquid equilibrium. The values obtained in this way agreed well with the experimental values.