The selection and design of an optimal solvent for extractive distillation require reliable vapour-liquid phase equilibrium data and knowledge of extraction mechanisms.Compared with time-consuming experiments,molecular simulation presents great potential in research on the properties of fluids.Therefore,in this work,Gibbs ensemble Monte Carlo was applied to successfully predict the vapour-liquid phase equilibrium data of binary and ternary systems containing benzene,thiophene and N,Ndimethylformamide(DMF) at P=101.3 kPa.The explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene,whereas the OPLS potential model was selected for DMF.The predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model.A good agreement was obtained,which corroborated the validity of the potential models.In addition,the extraction mechanism was explored by radial distribution function(RDF) of the liquid-phase structure.The RDFs showed that thiophene and benzene shared a similar liquidphase structure because of the intermolecular interaction.The distinct difference between the RDFs of DMF/benzene and those of DMF/thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene,which may be responsible for the extraction effect of DMF. The selection and design of an optimal solvent for extractive distillation require reliable vapor-liquid phase equilibrium data and knowledge of extraction mechanisms. Compared with time-consuming experiments, molecular simulation presents great potential in research on the properties of fluids.Therefore, in this work , Gibbs ensemble Monte Carlo was applied to successfully predict the vapor-liquid phase equilibrium data of binary and ternary systems containing benzene, thiophene and N, Ndimethylformamide (DMF) at P = 101.3 kPa.The explicit hydrogen version of the transferable potentials for phase equilibria potential model was chosen for benzene and thiophene, the the OPLS potential model was selected for DMF. The predicted phase diagrams were compared with experimental data and the UNIQUAC thermodynamic model. A good agreement was obtained, which corroborated the validity of the potential models. addition, the extraction mechanism was explored by radial distribution function (RDF) of the liq uid-phase structure.The RDFs showed that thiophene and benzene shared a similar liquidphase structure because of the intermolecular interaction. The distinct difference between the RDFs of DMF / benzene and those of DMF / thiophene is that the oxygen atom of DMF is more associated with hydrogen atoms of thiophene than that of benzene, which may be responsible for the extraction effect of DMF.