Collect. Czech. Chem. Commun. 1982, 47, 1420-1432

Some information on calculating the liquid-liquid equilibrium of ternary systems. an improvement of prediction of liquid-liquid equilibrium in ternary systems from binary equilibrium data

Július Surový, Ján Dojčanský and Soňa Bafrncová

Department of Processes and Apparatuses of Chemical Technology, Slovak Institute of Technology, 880 37 Bratislava


A possibility is described of improving the prediction of ternary liquid-liquid equilibrium data from binary ones by using three-parameter equations for calculating activity coefficients. The parameters for completely miscible pairs of liquids were determined from their vapour-liquid equilibrium data and those for partially miscible pairs of liquids from their mutual solubilities and from one limiting activity coefficient. A quantitatively correct prediction of the liquid-liquid equilibrium data was achieved in all cases by means of three different equations (NRTL equation, Redlich-Kister equation and Wilson equation modified by Novák and coworkers) in four hydrocarbon-hydrocarbon-polar solvent systems investigated.