Measurement And Correlation Of The Vapor-Liquid Equilibrium Of Cyclohexane + Ethanol Containing ILs

Ethanol and cyclohexane,as essential components of fundamental chemical original materials,are also widely used organic solvents in various industries.They have important value of separation,recycling and reuse.Ethanol-cyclohexane is a typical binary azeotrope system,which is difficult to achieve a high separation effect for simple separation techniques.In recent years,ionic liquid?ILs?has been used as extractant instead of traditional organic solvent to reduce environmental pollution and improve recovery.The kinds of ionic liquids with the heat of research also becomes popularier,the choice of the ionic liquid is one of the key factors of extraction distillation experiment.With the aid of compute can greatly improve the efficiency of scientific research work.In this paper,the molecular design method?COSMOthermX model?was adopted to design and select the ionic liquid,and three kinds of acetic ionic liquid were finally determined in the extraction and rectification process,methyltrioctyl ammonium acetate[N_1,8,8,8][Ac],1-decyl-3-methylimidazole ammonium acetate[DMIM][Ac]and1-hexadecyl-3-methylimidazole ammonium acetate[C₁₆MIM][Ac])were used as extractant,and vapor liquid equilibrium experiment was conducted under atmospheric pressure.The temperature dependence of some thermophysical properties?heat capacity,viscosity and density?of the three ions was measured and analyzed in the range of possible distillation operation temperature.The experimental results showed that:?1?the three ionic liquids designed in this paper all significantly improved the relative volatility of cyclohexane-ethanol,and the azeotrope of the system was shifted until the azeotrope was finally broken;?2?the separation capacity of three ionic liquids is:[N_1,8,8,8][Ac]>[DMIM][Ac]>[C₁₆MIM][Ac];The experimental results are consistent with the predicted results of COSMOthermX;?3?the correlation analysis of the data by the two models of NRTL and Wilson shows good consistency,which indicates that both models can be used for the data association of the system.Compared with the Wilson model,the fitting value of the NRTL model is more consistent with the experimental value;?4?the thermodynamic properties?specific heat,density and viscosity?of ionic liquids can also be used as one of the evaluation criteria for the separation ability of ionic liquids,providing a basis for the screening of ionic liquids.