复合萃取精馏分离乙酸乙酯-乙醇-水的研究

ISSN 1001-4160 Computers and Applied Chemistry VoL. 22, No. 6, 466-468, 2005Study on composite extractive distillation of ethyl acetate- ethanol- waterGU ZhengGui,, ZHI HuiZhen, MA ZhengFei and YAO HuQing(1. College of Chemical Technology, Nanjing University of Technology, Nanjing, 210013, Jiangsu, China; 2. Colledge ofChemistry and Environment Science, Nanjing Normal University, Nanjing, 210097, Jiangsu, China)Abstract: In this paper a new flow process of composite extractive distillation was introduced. Composite extractive distillation can beused to obtain high purity of ethyl acetate on the conditions of different solvent ratio and reflux ratio. In this process, glycerol and waterare used as proper extractive agents. Also proper solvent ratio and reflux ratio were groped through experiments of composite extractivedistillation in operation. When the ratio of solvent equals to 1: 1: 1 and reflux ratio equals to 4, high purity ethyl acetate(99. 5%)canbe obtained on the top of extractive distillation tower, at the same time aqueous alcohol (95%)can be obtained on the top of solventrecovery tower by the flow process. Glycerol can be recycled and water can be obtained easily without expensive. The process is simpli-fied and energy can be reduced. The basic data can be provided for industrial produce.Key words: ethyl acetate, ethanol, water, composite extractive distillation, extractive agent1 Introductionproper extraction agent. Glycerol, water, ethyl acetate,ethanol and water are mutually soluble liquids. GlycerEthyl acetate is an important solvent in industryd has extensive applications( Wang et al, 2003)ol can be easily recovered and water can extract ethanolhigh efficiently, moreover, water can be obtained easi-Ethyl acetate-ethanol-water can constitute boiling bina-ly and without consideration of its expensery and ternary mixture, separation of this mixture isdifficult by distillation. Ethyl acetate was refinedthrough azeotrope and extraction with water in tradition-al industry Furzer et al; Lloyd et al, 1999; Ran et al2000; Warnert et al, 2003 ), discharge capacity ofwaste water is more than three times product in thisproduction process, great amount of circulating waterdemand high energy. The saltquires high quality of equmany problems in productions( Gu et al, 2004; Li etFig. 1 Flow process of composite extractive distillation.al, 2000). If composite extractive distillation can beused( Gu et al, 2003), not only ethyl acetate 99. 5% 2.2 The process of composite extractive distilcan be obtained one time, but also above 95% ethanol lationcann Is 0The process of composite extractive distillation isthan feed, this flow process is simple and energy con- showed in figure 1. The mixture of feed(18% ethylsumption 1s lowacetate,70%ethanol, 12 water ) was added intothe tower 1 extraction distillation tower at the bot-2 The process references of composite extrac-tom,glycerol and water was added into the tower 1 at ative distillationbove part. The diameter of the2.1 Selection of composite extractive agentheight of the tower is 2 m. During the continuous com-The selection of composite extractive agent is the posite extractive distillation, the tower I was heated bymost important in the process of composite extractive reboiler (4), high purity of ethyl acetate (99. 5%)distillation. According to previous studies and large can be obtained through 3( cooler)in tower 1, 95%number of experiment data, glycerol and water are ethanol can be obtained in tower 2( solvent recoveryReceived: 2005-04-28: Revised 2005-06-11omputers and Applied Chemistry, 2005, 22(6): 466-468467tower). Glycerol can be obtained at the bottom of tow- and tower 2 are analysised by SP-6800 chromatograer 2 and recoveriedphy. The reagents are added into the column bypumps. Physical properties of the reagents are shownxperimentin table 1. The solvent ratio is feed quantities/ Ethylene3. 1 Reagents and instrumentsglycol quantities/ water quantitiesThe purity of the overhead and bottom of tower 1Table 1 Physical properties of the reagentsoiling Density kg/LAntoine constantskg/ kmol point℃Ethyl acetate88.10777,10.9008(20℃)16.15162790.5-57.15A. REthanol0.789(20℃)18.91193803.941.68Water18.015100.00.998(20℃)18.30363816.446.139.717 Distilled water62,06919721.117(20℃)20.250112.497Antoine equationlpo A,-B/(C,+T)(i=1, 2, 3)3. 2 Experiment results and discussionsAccording to ratio of solvent and reflux ratio varacetate-ethanol-water mixture are different the results5can be seen from followed figures 2-43. 2. 1 Effect of different reflux ratio on purity ofethyl acetateWhen the feed quantities, glycerol quantities andwater quantitieswater quantities are constant, reflux ratio (R)ischanged, the variation of ethyl acetate purity can bety with water quantitietatepurity can be seen in figure 3. The number of 1, 2seen in igure 2. When the ratio of solvent is 1.1: 1, 3, 4 represent respectively the solvent ratio(feed quan-with the increasing, of reflux ratio(R=1-4), the pu-rity of ethyl acetate is enlarged. as R=4 and 5, the putities/ Ethylene glycol quantities/water quantities )ofrity of ethyl acetate can be reached 99. 5%. It was con-1:1:1,1:1:1.5,1:1:2,1:1:2.5, with thecluded that purity of ethyl acetate can be improved byof water quantities, ethyl acetate purity is almost con-increasing reflux ratio(R). as R 2 4, the purity ofstant. When the solvent ratio is 1 1: 1, ethyl acetateethyl acetate is constant.urity is 99.51%feed/ glycerol rationFig 2 Variation of ethyl acetate purity with R.Fig 4 Variation of ethyl acetate purity3. 2. 2 Study on effect of solvent ratiowith glycerol quantities.3.2.2.1 Study on effect of increasing water quan-3. 2. 2. 2 Study on effect of glycerol quantitiestitiesWhen R=4, feed quantities and water quantitiesWhen R, feed and glycerol quantities are certainare certain. And change glycerol quantities, the varia-tion of ethyl acetate purity can be seen in figure 4. TheGu ZhengGui, et al: Study on composite extractive distillation of ethyl acetate-ethanol-water4 ConclusionsIncreasing the reflux ratio(R=1-4 )ethyl ace-tate purity can be improved When R24, ethyl acetatepurity is almost constant. Increasing glycerol and waterquantities respectively ethyl acetate purity can be im-proved slowly. When R=4 and the solvent ratio is 1:1: 1, we can obtain high purity(>99. 5%)ethyl ace-glycerol and water quantitiestate. The flow process is simple. And it requires lowFig 5 Variation of ethyl acetate purityenergy consumptionwith glycerol and water quantitiesReferencesnumber of 1, 2, 3, 4 represent respectively solvent ratio Wang J, Lin WB and Tan SY. Present situation and trend of technologfeed quantities/glycerol quantities/water quantities)of ethyl acetate. Applied Science and Technology, 2003, 3: 51is 1: 1: 1, 1: 1.5: 1, 1: 2: 1, 1: 2.5: 1, the solvent ratio Furzer lan A. Optimization of a wastewater system containing the temaryis 1: 1: 1, the purity of ethyl acetate is above 99. 59homogeneous azeotropic system ethyl acetate-ethanol-water. InFrom figure 4 we can conclude when glycerol quantitiesdustrial& Engineering Chemistry Research, 39(6): 1539-1545Berg and Lloyd. Separation of ethyl acetate from ethanol by azeotropicis increased that ethyl acetate purity is almost constantdistillation, US5993610. 19993.2.2. 3 Study on effect of glycerol and water Ran LL, et al. The constant boiling solvent and the process of constantquantitiesdistillation of separating ethyl acetate. CNI156718A, 2000.Warner R, Murphy J and David C, et al. Process for the simultaneouWhen R=4 and feed quantities are certain. glyc-coproduction and purification of ethyl acetate and isopropyerol quantities and water quantities are changed at theZG, et al. Measurement and calculation of three and four compoundsame time, the variation of ethyl acetate purity can bevle data for ethyl acetate-ethanol-glyceroL. Computers and Ap-seen in figure 5. The number of 1, 2, 3, 4 represent re-plied Chemistry, 2004, 21(6): 837-840spectively solvent ratio( feed quantities/ glycerol quan-Liangheng L and Hongyou W. The combined process of purification ethylacetate by salt extraction constant boiling distillationtities/water quantities)of 1: 0. 5: 1, 1: 1: 1, 1: 1. 5: 11:1.5:1.5,the solvent ratio is 1:1: 1, the purity ofGu ZG and Zhi HZ. Composite extraction separation of ethyl acetateethanol-water. CN: 1526692A. 2003.ethyl acetate is above 99. 5%. From figure 5 we can Cu ZG. Zhi HZ, Ma ZF and Yao HQ. Study on composite extractive dis.conclude when glycerol and water quantitiescreased that ethyl acetate purity is almost constantChemsitry,2005,22(6):466-468.复合萃取精馏分离乙酸乙酯-乙醇水的研究顾正桂12,职慧珍2,马正飞',姚虎卿(1.南京工业大学化学化工学院,江苏,南京,210013;2.南京师范大学化学与环境学院,江苏,南京,210097)摘要:介绍了乙酸乙酯在工业生产中的应用;在前人的研究基础上,采用合适的萃取剂,在萃取塔上考察了不同溶剂比、回流比等因素对产品纯度的影响,并摸索复合萃取分离乙酸乙酯乙醇水三元体系的适宜操作条件,在溶剂比为1:1:1,R=4时,能一次得到高浓度(995%)的乙酸乙酯,同时得到95%的乙醇溶液,得率高、能耗低,为工业试验提供了基础数据。关键词:乙酸乙酯;乙醇;水利;复合萃取精馏;萃取溶剂中图分类号:0641.3文獻标识码:A文章编号:10014160(2005)06466468收稿日期:20050428;修回日期:200506-11发明专利:CN1526692A作者简介:顾正桂(1962-),男,博士,教授级高工(香港远程教育学院终身教授),从事化工工艺与分离的研究。