Thermodynamic study of liquid mixtures of ethane and ethene

Abstract

The total vapour pressure, liquid density and the enthalpy of mixing have been measured for liquid mixtures of ethane and ethene at 161.39 K. The results have been used to estimate the excess properties of the system, the Gibbs energy, G^E, the volume, V^E, and the enthalpy, H^E. The mixtures show only slight deviations from ideality; the excess functions are positive, almost symmetric functions of composition. An equimolar mixture of ethane and ethene was found to have values of G^E= 98.9 J mol^–1, V^E= 0.156 cm³ mol^–1 and H^E= 192.7 J mol^–1. These results were examined theoretically using a perturbation theory based on spherical reference molecules. The effect on the excess properties of contributions from quadrupole–quadrupole, anisotropic-dispersion and anisotropic-overlap interactions is discussed.