Calculation of phase equilibria for solutions of strong electrolytes in solvent—water mixtures

Abstract

The Sander model for correlation and prediction of salt effects on vapor-liquid equilibria (VLE) combines a Debye—Hückel-type term with a modified UNIQUAC equation with concentration-dependent-parameters. The Debye—Hückel term has in this work been modified to ensure a more correct representation of the long-range forces. The modification has required a reestimation of previously published interaction parameters. It is shown that the modified model represents VLE for alcohol—water—salt mixtures with the same accuracy as the Sander model. The modified model has a broader range of applicability than the Sander model since the solvents acetone and 1-butanol have been added to water methanol ethanol, 1- and 2-propanol, and the ions Cu 2+, Ba 2+, Ni 2+ Hg 2+ Sr 2+, F −, and I − have been included besides Li +, Na +, K +, Ca 2+, Cl −, Br −, NO − 3 and CH 3COO −.