Isobaric Vapor-Liquid Equilibria for Ethanol plus Water plus Ethylene Glycol and Its Constituent Three Binary Systems

Isobaric vapor-liquid equilibria were measured for the ternary system ethanol + water + ethylene glycol and its three constituent binary mixtures at 101.3 kPa using a modified Rogalski-Malanoski equilibrium still. The thermodynamic consistency of experimental binary data was checked using the point and area tests. The experimental binary data were then correlated by the Wilson, nonrandom two-liquid (NRTL), and universal quasichemical activity coefficient (UNIQUAC) equations. The ternary vapor-liquid equilibria data were predicted using the binary parameters for the three equations with good accuracy. The selectivity of ethylene glycol as entrainer for the separation of the azeotropic system ethanol + water by extractive distillation was discussed using the NRTL parameters.