分离乙酸乙酯+乙醇+水体系:离子液体筛选、汽液相平衡和过程模拟  

Separation of ethyl acetate+ethanol+water system:Ionic liquids screening,vapor liquid equilibrium and process simulation

作　　者：李鑫[1] 王维[1] 张羽 谢湫钰 袁昊 LI Xin;WANG Wei;ZHANG Yu;XIE Qiuyu;YUAN Hao(School of Chemical Engineering,Dalian University of Technology,Dalian 116024,Liaoning,China)

机构地区：[1]大连理工大学化工学院,辽宁大连116024

出　　处：《化工进展》2025年第1期75-85,共11页Chemical Industry and Engineering Progress

摘　　要：乙酸乙酯、乙醇和水体系能够形成三个二元和一个三元的共沸体系。本文旨在以离子液体(IL)为萃取剂打破这些共沸,实现该三元体系的有效分离。基于COSMO-RS模型和黏度预测模型,计算了65种ILs的选择性、溶解度和黏度,发现1-丁基-3-甲基咪唑醋酸盐([BMIM][Ac])是65种ILs中最符合要求的萃取剂。进行了乙酸乙酯(1)+乙醇(2)+水(3)+IL(4)的四元汽液相平衡(VLE)实验,证实[BMIM][Ac]能够打破所有共沸体系,验证了筛选结果。NRTL和UNIQUAC方程关联四元VLE数据的均方根误差分别为1.69%和2.20%,关联结果可靠。通过量化计算定性和定量分析了IL分离该三元体系的机理,表明[BMIM][Ac]与乙酸乙酯发生弱氢键作用(-8.22kcal/mol,1kcal≈4.186kJ),与乙醇和水分别发生强氢键作用(-15.83kcal/mol和-16.14kcal/mol)。基于方程关联所得参数,模拟并优化了以IL为萃取剂分离乙酸乙酯+乙醇+水体系的萃取精馏过程,显示乙酸乙酯、乙醇和水的产品纯度均可达到0.999。研究结果验证了[BMIM][Ac]作为萃取剂分离该三元共沸体系工业化可行性。Ethyl acetate,ethanol and water can form a system with three binary and one ternary azeotropes.The aim of this study is to use ionic liquid(IL)as the extractant to break these azeotropes for effectively separating the ternary system.Based on the COSMO-RS model and the viscosity prediction model,selectivities,capacities and viscosities of 65 ILs were calculated.It was found that 1-butyl-3-methylimidazolium acetate([BMIM][Ac])was barged to the forefront as the extractant among 65 ILs.The vapor liquid equilibrium(VLE)experiments of ethyl acetate(1)+ethanol(2)+water(3)+selected IL(4)system were conducted.It was confirmed that the[BMIM][Ac]can effectively influence and break all the azeotropes in this system,proving the screening result.Correlation accuracies of the VLE data by the NRTL and UNIQUAC models were 1.69%and 2.20%of RMSDs,respectively.The slight errors emphasized the reliability of correlation results.The mechanism of separation for this ternary system with IL was qualitatively and quantitatively analyzed by quantum chemical calculations.It was showed that the[BMIM][Ac]formed weak hydrogen bond interactions with ethyl acetate(-8.22kcal/mol,1kcal≈4.186kJ)and strong hydrogen bond interactions with ethanol and water(-15.83kcal/mol and-16.14kcal/mol,respectively).Based on the correlated model parameters,an extraction distillation process was simulated and optimized for separating the ethyl acetate+ethanol+water system with the selected IL as the extractant.It was achieved that the mass fractions of ethyl acetate,ethanol and water can all reach 0.999.The research result demonstrated the industrial feasibility of separating this ternary azeotropic system with[BMIM][Ac]as the extractant.

关 键 词：离子液体 共沸(混合)物 萃取精馏 汽液平衡 机理分析 模拟 

分 类 号：TQ028.3[化学工程]