Ternary mixed solvents

composed of DMF(N

N-dimethylformamde)

DMSO(dimethylsulfoxide)and NMP(N-methylpyrrolidone)for separation of benzene and cyclohexane by extractive distillation

were examined in a vapor-liquid equilibrium experimental apparatus.The relative volatilities of benzene and cyclohexane were investigated.It was found that the ternary mixed solvents presented better “mixed solvent effect”

and were superior to the single solvent.The relative volatilities of benzene and cyclohexane at different molar mixed solvent ratios were determined

and the optimal molar ratio of the ternary mixed solvents was obtained.The modified MDNUIFAC model was used to correlate the experimental data

and the vapor-liquid equilibrium of benzene-cyclohexane-solvents system can be described well by the modified MDUNIFAC model.