Effect of ternary mixed solvent for separation of benzene-cyclohexane by extractive distillation

Ternary 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 solvents presented better mixed solvent effect,and were superior to the single solvent.The relative volatilities of benzene and cyclohexane at different molar solvent ratios were determined,and the optimal molar ratio of the ternary 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.