VAPOR-LIQUID-EQUILIBRIUM DATA FOR THE WATER 2-PROPANOL SYSTEM IN THE PRESENCE OF DISSOLVED SALTS

Experimental data are presented on VLE for the water-2-propanol system, and for the water-2-propanol-MgCl2 and water-2-propanol-MgBr2 systems. The salting-out effect of the salts on the binary mixture is shown together with the consequent shifting of the azeotropic composition. To correlate the experimental data, use was made of the Macedo model, which combines the modified UNIQUAC equation, containing concentration-dependent parameters, with a Debye-Huckel type term, thus ensuring a more correct representation of the long-range forces. The UNIQUAC interaction parameters between solvents and ions and between the two solvents are evaluated by the fitting of the experimental data. It is shown that the model represents the VLE for water-2-propanol-salt mixtures with an average accuracy of 2.5% in the total pressure and 2% in the vapour-phase mole fraction.