Ionic Liquid Extraction Screening Based on Molecular Simulation and Quantum Chemical Calculation to Separate Dimethyl Carbonate and Methanol
Since it takes a long time to select extractants for separating the azeotrope system by experimental methods,this work analyzed the microscopic mechanism of extractants for the separation of dimethyl carbonate-methanol azeotrope system through molecular simulation and quantitative calculation.The extraction separation ability for dimethyl carbonate-methanol azeotrope system of four ionic liquids was discussed by systematical calculation and analysis.By comparing the anion and cationic extraction selectivity of ionic liquid and its surface charge density,the best extractant was selected as 1-butyl-3-methylimidazole trifluoromethanesulfonate.Its high surface charge density can significantly enhance the hydrogen bond and electrostatic interaction between ionic liquid and target molecules,thus improving the ability of selective separation of dimethyl carbonate and methanol.The phase equilibrium data of ternary system were estimated by the conductor-like shielding model.The results showed that the separation effect of ionic liquid on dimethyl carbonate and methanol azeotrope system was from strong to weak as 1-butyl-3-methylimidazole trifluoromethane sulfonate>1-ethyl-3-methylimidazole bis(trifluorosulfonyl)imide salt>1-butyl-3-methylimidazole dibutyl phosphate>1-ethyl-3-methylimidazole diethyl phosphate.1-butyl-3-methylimidazole trifluoromethane sulfonate has high extraction selectivity and excellent extraction performance,and can be efficiently separated from dimethyl carbonate and methanol azeotrope system by extractive distillation.
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维普
