Separation Of Acetone And Chloroform By Using Ionic Liquids

Acetone-chloroform azeotropic system can not be separated by conventional distillation method.The commonly used organic solvents in extractive distillation are toxic and volatile.As a substitute for conventional organic solvents,ionic liquids have the advantages of strong selectivity and non-volatilization of solid salts.Its addition can change the interaction between the components of the system and eliminate azeotropic phenomena.Two ionic liquids,dimethyl 1,3-dimethylimidazole phosphate([MMIM][DMP])and diethyl 1-ethyl-3-methylimidazole phosphate([EMIM][DEP]),were synthesized.The vapor-liquid equilibrium data of acetone-chloroform-ionic liquids were determined and the separation ability of acetone-chloroform azeotropic system was investigated.By analyzing the vapor-liquid equilibrium data of acetone-chloroform-ionic liquids,it can be concluded that both ionic liquids can break the azeotropic system of acetone-chloroform.With the addition of ionic liquids,the activity coefficient of acetone increases and the activity coefficient of chloroform decreases.ILs have a great influence on the activity coefficient of acetone in the high.When the molar fraction of two ionic liquids is greater than 0.15,the relative volatility of acetone to chloroform is greater than 1.The NRTL thermodynamic model parameters were obtained by data regression using NRTL thermodynamic model.Compared with the experimental data,the average relative deviation of NRTL model is 1.82% and 1.79% respectively,which proves that NRTL model can well correlate the experimental data.Ionic liquids [EMIM] [DEP] and conventional organic solvents dimethyl sulfoxide were selected to compare the extraction ability at the same molar concentration.The results show that ionic liquids have better separation ability.The experimental results show that the three ionic liquids can be well applied to the separation of ethyl acetate-isopropanol azeotropic system.At the same time,the mechanism of ionic liquids is analyzed from the point of view of quantum chemistry.The configuration optimization and energy analysis of ionic liquids are carried out by using Gauss 09 A.Under the condition of BSSE correction and zero point energy correction,by comparing the interaction strength of ionic liquids with acetone and chloroform,it is found that the interaction energies of the two ionic liquids with acetone are quite different,and the interaction energies with chloroform are not very different.