SALTING EFFECT ON THE LIQUID-LIQUID EQUILIBRIA FOR THE PARTIALLY MISCIBLE SYSTEMS OF N-PROPANOL-WATER AND I-PROPANOL-WATER

The liquid-liquid equilibria (LLE) data were experimentally measured f or the partially miscible systems of n-propanol-water-NaCl, n-propanol -water-NaBr, n-propanol-water-KCl, and i-propanol-water-NaCl at 25 deg rees C. A method of calculation for the prediction of the salting effe ct on the LLE of organic aqueous solutions was proposed to correlate t he experimental tie-line data. In the proposed method, the activity co efficients of the solvents were calculated by Tan's modified Wilson mo del which was combined with a vapor pressure model of electrolyte solu tions, and the mean ionic activity coefficient was calculated by the G ibbs-Duhem equation. The parameters required by the proposed method co uld be estimated by the vapor pressures of a water-salt system and the alcohol-water interaction parameters in the liquid-phase activity coe fficient model. No ternary parameter was required. The proposed method has been used to predict the LLE data measured by this work, and the overall average deviation of tie-line compositions was 0.018.