Computer simulation of molecular liquid mixtures. I. A diatomic Lennard-Jones model mixture for CO2/C2H6

Abstract

Molecular dynamics simulations of model anisotropic molecules have been carried out which are intended to represent the molecular mixture CO2/C2H6. By paying careful attention to the methodology of the simulation it has been found possible to reduce the statistical and systematic errors to such an extent that the pressure-composition curve can be predicted for the mixture. Note that for the experimental system the difference between the maximum pressure of the mixture and the saturated vapor pressure of the pure components differ by about 10 atm. The model mixture displays an azeotrope in qualitative agreement with experiment. We believe this is the first time azeotropy has been observed by molecular dynamics. Detailed results are presented for the saturated liquid structure as a function of composition.