Studies of dynamic viscosity and Gibbs energy of activation of binary mixtures of methylcyclohexane with n-alkanes (C 5–C 10) at various temperatures

Abstract

Dynamic viscosities, η, for binary mixtures of methylcyclohexane with some n-alkanes, namely, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, and n-decane have been measured over the complete composition range at the temperatures 293.15 K, 298.15 K and 303.15 K and normal atmospheric pressure. Viscosity deviations Δln η, and excess Gibbs energy of activation Δ G* E, were calculated therefrom and were correlated by a Redlich–Kister type function in terms of mole fractions. For mixtures of methylcyclohexane with the studied n-alkanes Δln η is negative at all three temperatures. The Δ G* E values show positive values for the binary mixtures with n-decane, whereas negative values were observed for all remaining binary mixtures. An inversion of sign was observed for the mixtures with n-nonane at the rich mole fraction of methylcyclohexane. The Grunberg and Nissan and the McAllister three-body interaction models have also been used to correlate the kinematic viscosities of binary liquid mixtures with mole fractions.