Cyclohexane−Benzene Mixtures: Thermodynamics and Structure from Atomistic Simulations

Abstract

Mixtures of cyclohexane and benzene are investigated by means of all-atom molecular dynamics simulations. Thermodynamic properties such as density and enthalpy of mixing and diffusion coefficients were calculated for five different compositions and compared with experimental results. In agreement with experimental results, the calculated enthalpy of mixing indicates a slight nonideal behavior. Angle-dependent radial distribution functions have been analyzed in order to obtain detailed information about ring mutual orientations in pure liquids and in the mixtures. The most relevant configuration for benzene−benzene dimers in pure liquid and in a mixture with cyclohexane is the T-shape. Parallel configurations are distributed mainly in a broad range of shifting extent. In liquid cyclohexane the T-shape and sandwich configurations are equally relevant. Among the possible sandwich configurations, the nonshifted sandwich is the most relevant. In the cyclohexane−benzene dimers the nonshifted sandwich configuration dominates.