| Acetone and methanol,as important organic solvents and chemical raw materials,play a very important role in the chemical industry.However,azeotropic system formed by acetone and methanol cannot be separated effectively by conventional distillation methods.In this paper,extractive distillation technology is used to separate azeotrope system.The entrainer is the key to the extraction distillation process,so the selection of the appropriate extractant is the focus of this work.As a new and non-toxic new extractant,ionic liquid has a very important application value,which has attracted the attention of researchers.In this paper,COSMO-RS method and combined with literature report were selected for separating ionic liquids from acetone-methanol system.100 ionic liquids composed of 10anions and 10 cations were selected as screening objects.In order to investigate the effect of ionic liquids of different groups on the separation effect of acetone-methanol system,three ionic liquids were selected and synthesized:1-propyl-3-methylimidazolium bromide[PMIM]Br,1-allyl-3-methylimidazoliumbromide[AMIM]Brand1-allyl-3-methylimidazolium chloride[AMIM]Cl.The structure,purity and water content of ILs were measured by ~1H-NMR analysis,ionic liquid chromatography and Karl Fischermethod respectively and the results showed that ILs satisfied experimental requirement completely.Isobaric vapor–liquid equilibrium data for acetone+methanol and acetone+methanol+ILs systems were measured.The results showed that all the three ILs could improve the relative volatility of acetone to methanol.As the addition of ILs,the azeotropic point was shifted and then eliminated eventually.The separation abilities of the three ILs investigated in this work follow the specific order that[AMIM]Cl>[AMIM]Br>[PMIM]Br,and the results are consistent with the results of COSMO-RS screening.The experimental VLE data were well correlated with the NRTL model,indicating that NRTL model could be applied to this system. |
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