Correlation and prediction of salt effects on vapor–liquid equilibrium in alcohol–water–salt systems

• Published in: Fluid phase equilibria 2004-05, Vol.219 (2), p.257-264
• Main Authors: Sun, Tongfan, Bullock, Kerry R., Teja, Amyn S.
• Format: Article
• Language: English
• Subjects: Alcohol–water–salt systems; Bromley equation; Calculation method; Chemistry; Exact sciences and technology; General and physical chemistry; Liquid-vapor equilibria; Phase equilibria; Salt effect; Solvation; Vapor–liquid equilibria
• ISSN: 0378-3812; 1879-0224
• DOI: 10.1016/j.fluid.2004.01.006

A modification of the solvation model of Ohe is proposed for the calculation of vapor–liquid equilibria (VLE) in alcohol–water–salt systems. The modified method employs the Bromley equation to calculate the activity of water in salt solutions, and a one-parameter empirical expression to calculate the activity of the alcohol. The single parameter is obtained by fitting ternary alcohol–water–salt data. The method is simple to use and does not require data on the vapor-pressures of alcohol–salt mixtures that are seldom available in the literature. Experimental data for 17 salts in 36 alcohol–water–salt systems, covering a temperature range from 298 to 375 K, and salt concentrations up to about 8 m, were correlated using the new approach. In all, 69 data sets and 1045 data points were correlated satisfactorily. The method was also used to predict VLE in four ternary alcohol–alcohol–salt systems and one quaternary alcohol–alcohol–water–salt system with satisfactory results.