EXCESS GIBBS ENERGIES OF THE TERNARY-SYSTEM ETHANOL PLUS TETRAHYDROFURAN PLUS CYCLOHEXANE AT 298.15 K

Vapour-liquid equilibria for the ternary system ethanol + tetrahydrofu ran + cyclohexane and for the relevant binary mixtures have been deter mined at 298.15 K by head-space gas-chromatographic analysis of the va pour phase directly withdrawn from an equilibration apparatus. Experim ental data have been described with different equations (Redlich-Kiste r, Wilson, NRTL and UNIQUAC) and excess Gibbs energies G(E) as well as activity coefficients gamma(i) of components have been obtained. All systems exhibit positive deviations. The binaries containing cyclohexa ne form azeotropic mixtures at 298.15 K, while ethanol + tetrahydrofur an and the ternary systems do not. The excess entropy and the temperat ure dependence of G(E) and gamma(i) have been calculated in the whole ternary domain from the known excess enthalpy and heat capacity. (C) 1 997 Elsevier Science B.V.