Evaluation on the separation effect and extractant recovery efficiency of extractive distillation for separating ethyl acetate/methanol with ionic liquids as extractants

For the purpose of recycling resource and cleaner production, the extractive distillation schemes with different ionic liquids as extractants are proposed to separate ethyl acetate and methanol. In fact, the evaluation of extractants should not just focus on the separation effect, the effectiveness for the recovery of extractants which has a great influence on the overall benefits of extractive distillation process also need to be paid more attention, especially for the ionic liquids (ILs). On the basis of the VLE diagram, σ-Profiles, and interaction energy based on molecular dynamics, the separation effects of the selected extractant are following the order of 1-ethyl-3-methylimidazolium acetate ([EMIM][OAc]) > 1-ethyl-3-methylimidazolium diethyl phosphate ([EMIM][DEP]) > dimethyl sulfoxide (DMSO). However, the decomposition temperature of [EMIM][DEP] is much higher than that of [EMIM][OAc], which leads to the better effectiveness for extractant recovery. Then, several recovery configurations are explored owing to different decomposition temperature of selected ILs. The result shows that the heat integration assisted the process with [EMIM][DEP] as extractant which utilizes two-stage evaporators extractant recovery configuration has a better performance than other processes and can reduce 35.07% of TAC, 37.59% of energy consumption and 37.36% of gas emission compared with conventional extractive distillation process with DMSO as extractant