Monte Carlo predictions for vapor-liquid equilibria of N-Methyl-2-pyrrolidone + benzene + thiophene

An extension of the transferable potentials for phase equilibria united-atom (TraPPE-UA) force field to N-Methyl-2-pyrrolidone (NMP) is proposed in this work. The extensional force field can accurately predict the saturated liquid densities, vapor pressures, normal boiling point, heats of vaporization and critical properties of NMP. Gibbs ensemble Monte Carlo (GEMC) simulations are carried out to calculate the isobaric vapor-liquid equilibria for the binary mixtures of benzene + NMP, thiophene + NMP and their ternary mixture at 101.3 kPa. All of these simulation results are in good accordance with the available experimental data without introducing additional binary interaction parameters. In order to study the mechanism of extracting thiophene from benzene by NMP, NPT Monte Carlo simulations are performed to have obtained the radial distribution functions for the ternary liquid mixture benzene + thiophene + NMP. The results show that the oxygen atom of NMP forms stronger hydrogen bond with the hydrogen atom of thiophene than with that of benzene.