Enhancement of liquid phase splitting of water plus ethanol plus ethyl acetate mixtures in the presence of a hydrophilic agent or an electrolyte substance

The enhancement of phase splitting was investigated for the liquid mixtures of water + ethanol + ethyl acetate in the presence of a hydrophilic agent (glycerol) or an electrolyte compound (potassium acetate, KAc, or calcium chloride, CaCl2)(.) The liquid-liquid equilibrium (LLE) properties were measured for ternary systems of water + ethanol + ethyl acetate and water + ethyl acetate + CaCl2, and three quaternary systems, including water + ethanol + ethyl acetate + auxiliary agent (glycerol, potassium acetate, or calcium chloride), at temperatures ranging from 283.15 K to 313.15 K. The region of heterogeneity was found to increase as one of the auxiliary agents was introduced into the aqueous mixtures. By adding the same percentage of auxiliary agents, the magnitudes of phase-splitting enhancement follow the order of CaCl2 > KAc > glycerol. The Electrolyte-NRTL model was used to correlate the new LLE data for the investigated mixtures. In general, the model reproduces reasonably for the LLE phase envelops. (c) 2005 Elsevier B.V. All rights reserved.