HglBPgISi EQUIUBIilA ELSEVIER FluidPhaseEquilibria127 (1997) 181-190 Thermodynamic properties of water + normal alcohols and vapor-liquid equilibria for binary systems of methanol or 2-propanol with water Brahim Khalfaoui a, *, Abdessalem H. Meniai b, Rafael Borja c a Chemical Engineering Department, UMIST, Sackville Street, Manchester, M60 1QD, UK b Institut de Chimie Industrielle, Universite de Constantine, 25000 Constantine, Algeria c Instuto de la Grasa y sus Derivados (CSIC), Avda. Padre Garcia Tejero 4, 41012 Seville, Spain Received 15 January 1996; accepted 17 May 1996 Abstract Experiments have been carried out to determine densities and refractive indices of binary and ternary mixtures of water with normal alcohols (methanol and n-butanol) at 293.15 K. Also, vapor-liquid equilibrium data have been measured for binary systems of methanol-water and 2-propanol-water at atmospheric pressure, from which the excess Gibbs free energy was computed for both systems. The experimental vapor-liquid equilibrium (VLE) data have been compared with those predicted by the Wilson, NRTL and UNIQUAC equations. Agreement has been found to be very satisfactory. Keywords: Methanol-H20 systems; 2-Propanol-H20 systems; Density;Refractive index; Gibbs free energy; Vapor-liquid equilibria; Water-n-alcohol systems I. Introduction Vapor-liquid equilibrium data are always required for engineering use such as in design and, especially, in distillation, which is the most common operation performed in the chemical industry for the separation of liquid mixtures. In previous work [1,2] we presented experimental results of vapor-liquid equilibrium (VLE) measurements for binary mixtures of water with chlorinated hydro- carbons and water with brominated hydrocarbons. The present work reports the VLE results of measurements on binary mixtures of methanol-water and 2-propanol-water at atmospheric pressure. The experimental results have been compared with those predicted by the Wilson [3], NRTL * Corresponding author (on leave from Universite de Constantine, 25000 Constantine, Algeria). 0378-3812/97/$17.00 Copyright © 1997ElsevierScienceB.V. All rightsreserved. PII S0378-3812(96)031 29-9