Phase Behavior And Separation Process Design Of Imidazole Ionic Liquid Alkane Alcohol Ketone Azeotrope

Ionic liquid?ILs?as a green alternative extractant which can be used as a traditional solvent has been widely concerned.In view of its wide application prospect,the extraction and separation mechanism of alkane-alcohol/ketone azeotrope by ILs was explored.The experimental data of liquid-liquid equilibrium?LLE?of ILs-alkane-alcohol/ketone system were measured,and the separation process of alkane-alcohol/ketone system using ILs as extractant was designed and optimized.Based on COSMO-SAC model,the surface charge densities of cations,anions,acetone,methanol,n-heptane and n-hexane were calculated by quantum chemical method.The infinite dilution activity coefficient of ILs-alkane-alcohol/ketone system was calculated,and the distribution coefficient and selectivity of the system were calculated.The LLE experimental data of n-hexane-acetone-ILs?[BMIM][OTF],[HMIM][NTF₂],[HMIM][OTF]and[HMIM][PF₆]?,n-heptane-acetone-ILs?[BMIM][OTF],[HMIM][OTF],[BMIM][NTF₂]and[BMIM][PF₆]?and n-hexane-methanol-ILs?[BMIM][NTF₂],[DMIM][NTF₂]and[BMIM][PF₆]?systems were determined at 298.15K and 101.3kPa.The influence of anionic and the alkyl chains of cationic in ILs on the extraction of alkane-alcohol/ketone system were analyzed and compared,and the consistency of LLE experimental data of ILs-alkane/alcohol ketone system was tested by using Othmer-Tobias equation and Hand equation.The LLE experimental data of ILs-alkane-alcohol/ketone system were regressed by NRTL model and UNIQUAC model,and the binary interaction parameters of the two models were obtained.In view of alkane-alcohol/ketone azeotrope system,the definition of ILs was completed by using the critical properties of ILs.According to the binary interaction parameters calculated by NRTL model,the technological process of ILs-alkane-alcohol/ketone system was designed and optimized by Aspen Plus 8.4software.The effects of the number of plates of the extraction column and the ratio of the extractant to the feed on the extraction efficiency were explored,which provided an important reference for the industrial application of ILs as the extractant in the separation of alkane-alcohol/ketone system.