No abstract

In recent years, ionic liquids (ILs) have received considerable attention for their use in chemical industry and are considered to be an alternative to conventional entrainers in extractive distillation, because of their ability to selectively separate azeotropic/close boiling mixtures [1,2].In this work, an extractive distillation process was investigated, comparing the imidazoliumbased ionic liquids (1-ethyl-3-methylimidazolium acetate), [EMIM][OAc] and (1ethyl-3methylimidazolium dicyanamide), [EMIM][DCA] with ethylene glycol (EG) organic solvent for ethanol dehydration. These ionic liquids were proposed with the aim of obtaining a higher selectivity than EG traditional solvent.The thermodynamic behavior of the ethanol/water mixture in the presence of the solvent was studied using Simulis Thermodynamics software; ionic liquids were created as new components, with the required thermodynamic and physical property parameters. The experimental data for ethanol/water/ethylene glycol mixture were fitted with the nonrandomtwo-liquid (NRTL) activity coefficient model to determine the binary interaction parameters, while, binary interaction parameters for ionic liquids were obtained from the literature.The vapor liquid equilibrium (VLE) behavior of ethanol-water in the presence of [EMIM][DCA] showed that this ionic liquid enhances the relative volatility of ethanol and allows to eliminate the ethanol-water azeotrope. The main operating conditions of anhydrous ethanol production have been determined to achieve a high distillate purity of 99.9 mol% in ethanol. It has been found that the [EMIM] [DCA] ionic liquid is very effective for the separation of ethanol-water azeotropic system even at low concentrations and less energy consuming compared to the conventional benchmark solvent EG.