Separation Of Ethyl Acetate-Ethanol And Measurement Of Vapor-Liquid Equilibrium With Ionic Liquids

As one of most widely used ester, ethyl acetate was manufactured along with a lot of ethanol. Ethyl acetate and ethanol form a minimum-boiling azeotropic systems at atmospheric pressure, and it’s difficult to use the traditional separation methods to separate the azeotrope.The key of extractive distillation is choosing the entertainer. The disadvantages of organic solvents included large usage, etc. Ionic liquids (ILs) are organic salts in room temperature and have special properties, such as negligible vapor pressure and solubility in polar and nonpolar compounds, etc. Apart from that, they have outstanding salting-out or salting-in for azeotropic systems and can be easily separated and recycled. Recently, some scholars focused on the separation using ILs as entrainers.In this work, three kinds of ILs were selected as entrainers using in the separation of ethyl acetate and ethanol, namely 1-methyl-3-methylimidazole dimethylphosphate ([MMIM][DMP]), 1-ethyl-3-methylimidazole diethyl- phosphate ([EMIM][DEP]), 1-butyl-3-methylimidazole dibutylphosphate ([BMIM][DBP]). Isobaric vapor-liquid equilibrium data for binary and ternary systems were measured by using a vapor-liquid equilibrium still (CE-2) and separation efficiency of them is investigated.The VLE data of binary systems in constant pressure were measured, including ethyl acetate-ethanol, ethyl acetate-IL and ethanol-IL. The result showed that the activity coefficient of ethyl acetate was increasing along with the adding of ILs. The relationship between the increasing amplitude and ILs is [MMIM][DMP]> [EMIM][DEP]> [BMIM][DBP]. While the activity coefficient of ethanol was on the contrary.The VLE data of ternary systems adding ILs in constant pressure were measured. It could be inferred that when the mole concentration of ILs in the system reaching to 0.15, the azeotropic point was disappeared. The ILs [MMIM][DMP] performed the best in separate ethyl acetate and ethanol azeotropic system, the ability of [EMIM][DEP] and [BMIM][DBP] were decreased in turn.The VLE data of the binary and ternary systems were correlated by e-NRTL thermodynamic model in this work. Compared and analysed both calculated and experimental data, it showed that the e-NRTL thermodynamic model were available in correlation of the experimental data of binary and ternary system.In a word, these three kinds of ILs can be used as entrainers in the extractive distillation separation of ethyl acetate and ethanol.