(Liquid + liquid) equilibria of {benzene + cyclohexane + two ionic liquids} at different temperature and atmospheric pressure

Abstract

(Liquid+liquid) equilibrium data of the following ternary and quaternary systems at different temperatures and mass fractions of ionic liquids (ILs) were measured at atmospheric pressure, i.e., {cyclohexane+benzene+1,3-dimethylimidazolium dimethylphosphate ([MMIM][DMP])} at 298.2K, {cyclohexane+benzene+1-methylimidazolium tetrafluoroborate ([MIM][BF4])} at 338.2K, {cyclohexane+benzene+[MIM][BF4]+[MMIM][DMP]} at (298.2 and 313.2)K, and {cyclohexane+benzene+1-methylimidazolium perchlorate [MIM][ClO4]+[MMIM][DMP]} at 298.2K. The results indicate that both selectivity and distribution factor of the IL mixture for benzene are lower than that of pure IL [MMIM][DMP] at a specified condition, and decrease with the increase of the mass fraction of [MIM][BF4] or [MIM][ClO4] in its mixture of [MMIM][DMP] and the mole fraction of benzene. The extremely high selectivity of [MIM][BF4] and [MIM][ClO4] for aromatic compounds as predicted by the COSMOS-RS model is not justified by the present experimental results, and on the contrary, they show a relatively lower selectivity and extraction capacity for benzene than [MMIM][DMP].