Liquid-liquid extraction of styrene from ethylbenzene using ionic liquids

摘要

The performance of the 3-(2-methoxyethyl)-1-methylimidazolium dicyanamide ([(C2OCH3)MIM][DCA]), 1-(4-methoxy-4-oxobutyl)-3-methylimidazolium dicyanamide ([(C3COOMe) MIM][DCA]) and choline dicyanamide ([Chol][DCA]) ionic liquids (ILs) as alternative solvents in the liquid-liquid extraction of styrene from ethylbenzene was evaluated at temperature T = 298.15 K and ambient pressure. This work is a continuation of selection of [DCA] based ILs for the separation of close-boiling organic mixtures. The liquid-liquid equilibrium (LLE) in ternary systems of {IL (1) + styrene (2) + ethylbenzene (3)} is presented for three synthesized by us ILs. The solubility of ILs in the hydrocarbon rich phase can be considered as negligible, simplifying the purification of the raffinate. The comparison of different ILs is presented in the studied separation problem. It was observed that the best average separation selectivity in this work has [(C3COOMe) MIM][DCA] (S-AV = 2.29, beta(AV) = 0.40) at T = 298.15 K. The data presented here indication the possible use of [(C3COOMe) MIM][DCA] as good solvent for the separation of styrene from ethylbenzene using solvents extraction. The experimental tie-lines were correlated with the non-random two liquid NRTL model. (C) 2018 Elsevier Ltd.