Separation Of Ethyl Acetate And Methanol Azeotrope By Extractive Distillation With Ionic Liquid

Ethyl acetate and methanol are important raw materials in chemical production process,while ethyl acetate and methanol exist in the form of azeotrope under atmospheric pressure.The distillation method cannot separate the azeotrope of ethyl acetate and methanol.Recently,as a green solvent,the ionic liquid has special properties such as negligible saturated vapor pressure,recyclability,and strong designability.It is expected to replace traditional organic solvents and become a new type of extractant used in the process of extractive distillation.Based on this,the azeotropic system of ethyl acetate and methanol was separated by using ionic liquid as extractant.The research content of this article includes:1)Cosmothermx was used to screen 420 kinds of ionic liquids composed of 21 common anions and 20 cations.Considering the solubility,price,availability and other related factors of ionic liquids,[N₄₄₄₁][Ac],[N₄₄₄₁][Pr]and[DMIM][Ac]were chosen as the ionic liquids for the separation of ethyl acetate-methanol azeotrope.2)Under the condition of 101.3k Pa,the vapor-liquid equilibrium data of binary system of ethyl acetate+methanol and ternary system containing ionic liquid(ethyl acetate+methanol+[N₄₄₄₁][Ac]/[N₄₄₄₁][Pr]/[DMIM][Ac])were measured.The results show that the addition of three kinds of ionic liquids can increase the relative volatility of ethyl acetate relative to methanol and play a role in breaking the azeotropy of the system,and the greater the concentration of the ionic liquid,the better the destruction effect on the azeotrope;the NRTL activity coefficient model was used to perform regression fitting on the experimental data.It showed that NRTL model was suitable for ternary system containing ionic liquids.The minimum mole fraction of the three ionic liquids[N₄₄₄₁][Ac],[N₄₄₄₁][Pr],[DMIM][Ac]can be obtained by NRTL model,respectively,which were 0.045,0.047 and 0.077,namely[N₄₄₄₁][Ac]as the best extractant for the separation of ethyl acetate methanol azeotrope.3)Using Aspen Plus process simulation software to simulate the double-tower continuous extractive distillation process for ethyl acetate-methanol-[N₄₄₄₁][Ac]system,under the premise that the mass fraction of the product is higher than 99.9%,the effects of changes in process parameters such as the number of theoretical plates of distillation column,the feed position of the raw materials,the amount of extractant and reflux ratio on the separation efficiency and equipment energy consumption of ethyl acetate methanol system were studied by using sensitivity analysis tool.It provides a reference for the actual production operation in the future.