Modelling of liquid-liquid equilibria of mixed solvent electrolyte systemsusing the extended electrolyte NRTL

Liquid-liquid equilibria of mixed solvent electrolyte systems were correlat ed using an extended electrolyte NRTL model. The electrolyte NRTL expressio n for the activity coefficients has been modified by taking into account th e derivatives to the solvent composition of the physical properties and by a new Bronsted-Guggenheim (BG) expression. In addition to some ternary mixe d solvent electrolyte systems, the model has been applied to the quaternary systems that are of importance in the extraction process of epsilon-caprol actam: water + epsilon-caprolactam + solvent + ammonium sulfate (AS), The L iquid-liquid equilibria of the ternary and quaternary systems involved and the mean activity coefficients of the salt + water systems were used simult aneously to obtain the adjustable parameters. The results are compared to t he original electrolyte NRTL of Chen. (C) 2000 Elsevier Science B.V. All ri ghts reserved.