Liquid−Liquid Equilibria for Benzene + Cyclohexane + 1-Butyl-3-methylimidazolium Hexafluorophosphate

Experimental liquid−liquid equilibrium data were measured for benzene + cyclohexane + 1-butyl-3-methylimidazolium hexafluorophosphate ([C 4 mim]PF 6 ) at atmospheric pressure and (298.2, 308.2, and 318.2) K. The selectivity of [C 4 mim]PF 6 for benzene is in the range of (20 to 60) when the mass fraction of benzene in the cyclohexane-rich phase is less than 0.08, which increases with a decrease in benzene content. The selectivity is also dependent on the temperature. The highest selectivity is obtained at 308.2 K in this work. Considering the high selectivity for benzene and the negligible solubility in benzene + cyclohexane mixtures, [C 4 mim]PF 6 may be used as a potential extracting solvent for the separation of benzene and cyclohexane.