Vapour-liquid equilibrium of the acetone-methanol system in the presence of KSCN and comparison with other salts

The effect of KSCN at salt mole fractions of 0.01-0.05 and at saturation on the VLE of the binary acetone-methanol system has been experimentally investigated at 101.32 kPa using a modified Othmer equilibrium still. The experimental data were correlated by the electrolytic NRTL model [B. Mock, L.B. Evans and C.C. Chen, AIChE J., 32 (1986) 1655-1664], the extended UNIQUAC equation [B. Sander, A. Fredensland and P. Rasmussen, Chem, Eng. Sci., 41 (1986) 1171-1183] and the modified Wilson and NRTL models proposed by Tan [T.C. Tan, AIChE J., 31 (1985) 2083-2085; Chem. Eng. Res. Des., 65 (1987) 355-366; Trans. Inst. Chem. Eng., 68 (1990) 93-102]. The results were compared with those obtained by Tan's predictive models. A crossover between the salting-out and salting-in effects on acetone and a non-azeotropic minimum in the temperature-composition diagram were observed at low and high salt concentrations. Based on the solubility data in the mixture, comparisons with the effect of other salts on the same mixed solvent were made. (C) 1997 Elsevier Science B.V.