Equilibrium in biphasic aqueous systems: A model for the excess gibbs energy and data for the system H2O−NaCl-1-propanol at 25°C

Liquid-liquid equilibrium data were measured for the 1-propanol-NaCl–H₂O system at 25°C. Liquid-liquid equilibrium in aqueous biphasic salt systems containing salts and alcohols or polymers was modelled using an expression for the excess Gibbs energy of the solution. The model is based on modified forms of the nonprimitive Mean Spherical Approximation, the Bromley equation, and the Flory-Huggins theory and requires three and five adjustable parameters for ternary and quaternary systems, respectively. The model accurately correlated binary water-polymer or water-alcohol vapor-liquid equilibrium data and liquidliquid equilibrium data for seven ternary and three quaternary aqueous biphasic salt systems.Presented at the Symposium, 76^th CSC Congress, Sherbrooke, Quebec, May 30–June 3, 1993, honoring Professor Donald Patterson on the occasion of his 65^th birthday.