Isobaric Vapor–Liquid Equilibrium for Ethyl Acetate + Chloroform with Ionic Liquids [EMIM][OAc], [BMIM][OAc], and DMSO + [EMIM][OAc] as Entrainers at 101.3 kPa

Abstract

Ionic liquid 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]), 1-butyl-3-methylimidazolium acetate ([BMIM][OAc]), and a mixture of [EMIM][OAc] and dimethyl sulfoxide (DMSO) were used as solvents to separate the maximum boiling azeotropic mixture of ethyl acetate and chloroform. The ternary vapor–liquid equilibrium (VLE) data of ethyl acetate + chloroform + [EMIM][OAc] were measured at 101.3 kPa. The liquid phase is partially soluble when the concentration of ethyl acetate and [EMIM][OAc] is high in the ternary system, and DMSO is employed to enhance the solubility of [EMIM][OAc] in ethyl acetate. Different entrainers were compared by measuring the VLE of ethyl acetate + chloroform + DMSO, ethyl acetate + chloroform + [BMIM][OAc], and ethyl acetate + chloroform + [EMIM][OAc] + DMSO at 101.3 kPa. All of the entrainers can improve the relative volatility of ethyl acetate to chloroform. The salting-out effects of the ILs [EMIM][OAc] and [BMIM][OAc] are significantly greater than that of DMSO. Organic solvent DMSO can enhance the selectivity of [EMIM][OAc] at high ethyl acetate concentration. The effects of the entrainers were analyzed by sigma-profiles. The nonrandom two-liquid (NRTL) activity coefficient model was adopted to correlate the experimental data. The binary interaction parameters of the NRTL equation were obtained, and the correlation results agreed well with experimental results.