Flexibility, multiplicity and symmetry of wilson parameters and vapor—liquid equilibrium in multicomponent systems

Abstract

On the basis of previous work, a method is presented which correlates the flexibility, multiplicity and symmetry of the Wilson parameters with activity coefficients at infinite dilution and the relations among parameters to evaluate vapor—liquid equilibria of ternary systems. To confirm it, gas—liquid chromatography was used to measure the activity coefficients at infinite dilution of a volatile solute in nonvolatile solvents, separately and in their mixtures. The limiting activity coefficients have been combined with the Hála constraint predict the vapor—liquid equilibria of ternaries. The predicted results are satisfactory when compared with literature values. From vapor—liquid equilibrium data of the Dutmund data bank, 13 ternary and the corresponding binary systems were selected, and Wilson parameters evaluated using the Hála constraint. The errors between the predicted results and experimental data are small. In this work we have also estimated the one-side upper limits of confidence of deviations in the prediction. Besides, predictions have also been made for the three binary systems in two ternaries and with two binaries and one datum point of six ternaries.