Solvent Selection for Cyclohexane−Cyclohexene−Benzene Separation by Extractive Distillation Using Non-Steady-State Gas Chromatography

The infinite-dilution activity coefficients of cyclohexane, cyclohexene, and benzene in N, N -dimethylformamide, N -methylpyrrolidone, N, N -dimethylacetamide, phenyl acetate, and dimethyl malonate have been determined at temperatures ranging from 40 to 80 °C, by non-steady-state gas chromatography. From these data, the limiting selectivity−solvency properties for cyclohexane−benzene, cyclohexene−benzene, and cyclohexane−cyclohexene, in the presence of the aforementioned solvents, are studied, and the solvents tested are considered for the cyclohexane−cyclohexene−benzene separation by extractive distillation. According to the results, N, N -dimethylacetamide seems to be an adequate solvent for the cyclohexane−benzene and cyclohexene−benzene separations. The separation of cyclohexane−cyclohexene is the most difficult, in spite of the difference of boiling points, much higher than for cyclohexane−benzene.