The selectivity of alkyl-substituted imidazolium cation-based ionic liquids (ILs) with different anion: Tf2N, PF6, Tf2N and BF4, namely 1-Butyl-3-methylimidazolium bis(trifluoromethyl sulfonyl)imide ([BMIM][Tf2N]), 1-Butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]), 1-Ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ([EMIM][Tf2N]), 1-Methyl-3-octyl imidazolium tetrafluoroborate ([OMIM][BF4]), was tested for the extraction of benzene, toluene and p-xylene(BTX) aromatics with hexane mixtures. Liquid-liquid equilibrium (LLE) data were determined for the six ternary mixtures {hexane (1)+BTX (2)+ILs (3)} at 298.15 K and atmospheric pressure. In addition, binary LLE data from 293.15 K to 318.15 K are also reported for the system {hexane (1)+[BMIM][Tf2N] (2)}. The ternary experimental LLE data were satisfactorily correlated with the NRTL activity coefficient model. The degree of consistency of the tie lines was estimated by using the Othmer-Tobias equation, for which a good linear correlation coefficient (R2) was obtained. As a result, the selectivity of ILs as potential solvents for the extraction of BTX from aliphatic components was found to be much higher than unity and PF6 anion showed higher selectivity compared to other anions.

Liquid-liquid Equilibrium Separation Aliphatic Aromatic Ionic Liquid

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