PREDICTION OF VAPOUR-LIQUID EQUILIBRIA FROM HEAT OF MIXING DATA.

The abilities of the Wilson and NRTL equations to predict vapor-liquid equilibria from heat of mixing data are compared. Both equations give reasonable results for systems with heats of mixing less than ca 120 cal/g mol. However, for other systems, the Wilson equation is unable to describe the heat of mixing data, while the NRTL equation sometimes gives erroneous predictions of partial miscibility. This problem with the NRTL equation can be overcome, but the VLE predictions still lack sufficient accuracy.