Vapor-liquid equilibria of mixtures containing alkanes, carbon dioxide, and nitrogen

New force fields for carbon dioxide and nitrogen are introduced that quantitatively reproduce the vapor-liquid equilibria (VLE) of the neat systems and their mixtures with alkanes. In addition to the usual VLE calculations for pure CO₂ and N₂, calculations of the binary mixtures with propane were used in the force-field development to achieve a good balance between dispersive and electrostatic (quadrupole-quadrupole) interactions. The transferability of the force fields was then assessed from calculations of the VLE for the binary mixtures with n-hexane, the binary mixture of Co₂/N₂, and the ternary mixture of CO₂/N₂/propane. The VLE calculations were carried out using configurational-bias Monte Carlo simulations in either the grand canonical ensemble with histogram - reweighting or in the Gibbs ensemble.