Thermodynamics Research Center / ThermoML | Journal of Chemical and Engineering Data

ABSTRACT

Vapor-liquid equilibria for the ternary system 2-methoxyethanol + tetrahydrofuran + cyclohexane and for the constituent binary mixtures containing 2-methoxyethanol have been determined at 298.15 K. In addition, for a better understanding of the phenomenology, the binary mixtures 2-methoxyethanol + ethanol and 2-ethoxyethanol + cyclohexane were also investigated. Vapor-liquid equilibrium data were collected by headspace gas chromatographic analysis of the vapor phase directly withdrawn from an equilibrium apparatus. Molar excess Gibbs energies GE and activity coefficients were calculated therefrom. All binaries display positive GE deviations from ideality, the largest being observed for the binary 2-methoxyethanol + cyclohexane, as well as the ternary mixtures over the whole mole fraction range, indicating that interactions in the pure liquids are not compensated for by new interactions in the mixtures. A positive sign is also displayed by HE and VE of the ternary system, while the entropy contribution to GE, -TSE, is positive in the region rich in the binary 2-methoxyethanol + cyclohexane and negative in the region rich in tetrahydrofuran + cyclohexane. The analysis of activity coefficients allows us to point out the role of hydrogen bonds in the cross-association of alcohols with polar molecules and the self-association both in pure liquid alcohol and in mixtures with hydrocarbons.