LAUSR

Abstract The liquid-liquid equilibrium (LLE) data for three ternary mixtures of n-hexane + benzene + sulfolane, + 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][NTf2]) and + 1-ethyl-3-methylimidazolium ethylsulfate ([EMIM][EtSO4]) and two quaternary ones of n-hexane + benzene + mixed ionic liquids respectively with fixed molar ratio 9:1 and 1:9 of [EMIM][NTf2] to [EMIM][EtSO4] were determined experimentally at (303.15, 313.15 and 323.15) K and atmospheric pressure. The experimental results showed that the ionic liquid of [EMIM][NTf2] captures higher molar distribution coefficient while one of [EMIM][EtSO4] is characterized with higher molar selectivity, compared to the sulfolane solvent that is extensively used for aromatic extraction in industry. The improvement of the composite separation performance for n-hexane and benzene was observed through mixing the above two ionic liquids. To represent the experimental diagram, the activity coefficient model of Non-Random Two-Liquid (NRTL) was employed to correlate the experimental data and good agreements between theoretical and experimental results were obtained. In general, the selected ionic liquid and its mixture in this work could be considered as a potential substitute for sulfolane.