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 Zheng Gui,, 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%)canextractive distillation tower, at the same time aqueous alcohol (95%)can be obtained on the top of solventecovery tower byprocess. Glycerol can be recycled and water can be obtained easily without expensive. The process is simplified and energy can be reduced. The basic data can be provided for industrial produce.Key words: ethyl acetate, ethanol, water, composite extractive distillation, extractive agentIntroductionproper extraction agent. Glycerol, water, ethyl acetatethanol and water are mutually soluble liquids. GlycerEthyl acetate is an important solvent in industryol can be easily recovered and water can extract ethanoland has extensive applications( Wang et al, 2003)high efficiently, moreover, water can be obtained eaEthyl acetate-ethanol-water can constitute boiling binaly 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 salt extraction distillation re-quires high quality of equipment and easily causesnany problems in productions( Gu et al, 2004; Li etFlow process of composite extractiveal, 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 lationcan be obtained, water consumption is only 2 timesThe 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 is lowacetate,70% ethanol, 12 water )was added into2 The process references of composite extrac-the tower 1( extraction distillation tower )at the bottive distillationtom, glycerol and water was added into the tower 1 at a-bove part. The diameter of the tower is 40 mm, the2.1 Selection of composite extractive agentheight of the tower is 2 m. During the continuous comThe selection of composite extractive agent is the positeer 1 was heatedost important in the process of composite extractive中国煤化工acetate(99.5%)distillation. According to previous studies and large can belCNMHGower 1. 95%number of experiment data, glycerol and water are ethanol can be obtained in tower 2( solvent recoveryReceived:200540428; Revised:200506-11005,22(6):46tower). Glycerol can be obtained at the bottom of tow- and tower 2 are analysised by SP-6800 chromatogra-er 2 and recoveriedphy. The reagents are added into the column bypumps. Physical properties of the reagents are shown3 Experimentin table 1. The solvent ratio is feed quantities/ Ethylene3.1 Reagents and instrumentsglycol quantities/water quantitiesThe purity of the overhead and bottom of tower 1Density kg/L.Antoine constantskg/ kmol point℃Ethyl acetate88.177.10.9008(20℃)16.15162790.557.157.700AEthanol46.0.789(20℃)18.9119Water18.015100.00.998(20℃)18.30363816.4-46.139.717 Distilled waterlene glycol62.069197.21.117(20℃)20.250128.2512.497. .1 n0T)(i=123)3. 2 Experiment results and discussionsaccording to ratio of solvent and reflux ratio vard, the results of composite extractive distillation ethylacetate-ethanol-water mixture are different the resultscan be seen from followed figures 2-43. 2. 1 Effect of different reflux ratio on purity ofethyl acetateen thefeed quantities, glycerol quantities andwater quantities are constant, reflux ratio (R)ischanged, the variation of ethyl acetate purity can beFig 3 Variation of ethyl acetate purity witte purity can be seen in figure 3. The number of 1, 2eenin figure 2. When the ratio of solvent is 1: 1: 1with the increasing, of reflux ratio(R=1-4), the pu3, 4 represent respectively the solvent ratio(feed quanrity 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 the increasingcluded that purity of ethyl acetate can be improved byof water quantities, ethyl acetate purity is almost con-increasing reflux ratio(R). as R>4, thestant. When the solvent ratio is 1: 1: 1, ethyl acetateethyl acetate is constantfeed/glycerol rationariation nf ethyl中国煤化工3. 2.2 Study on effect of solvent ratio3.2.2.1 Study on effect of increasing water quan-3.2.2CN MH Grol quantitiesWhen r=4. feedWhen R, feed and glycerol quantities are certainare certain. And change glycerol quantities, the varia-And change water quantities, the variation of ethyl ace-tion of ethyl acetate purity can be seen in figure 4. Theu ZhengGui, et al: Study on composite extractive distillation of ethyl acetate - ethanol-wateronclusionsIncreasing the reflux ratio(R=1-4 )ethyl ace-tate purity can be improved. When R>4, ethyl acetatepurity is almost constant. Increasing glycerol and waterquantities respectively ethyl acetate purity can be improved 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 Furer lan A. Optimization of a wastewater system containing the termaryis 1: 1: 1, the purity of ethyl acetate is above 99. 5%homogeneous 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 constanttitiesdistillation of separating ethyl acetate. CNI156718A, 2000Warmer R, Murphy J and David C, et al. Process for the simultaneousWhen R=4 and feed quantities are certain. glyc-coproduction and purification of ethyl acetate and isopropyl acetateerol quantities and water quantities are changed at theUSo166964A.2003Gu ZG, et al. Measurement and calculation of three and four compoundssame time, the variation of ethyl acetate purity can bevle data for ethyl acetate-ethanol-glycerol. Computers and Apseen in figure 5. The number of 1, 2, 3, 4 represent re-plied Chemistry, 2004, 21(6): 837-840spectively solvent ratio(feed quantities/glycerol quanangheng 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: 1CN1043495A,2000.1: 1.5: 1.5, the solvent ratio is 1: 1: 1, the purity of Gu zG and Zhi Hz. Composite extraction separation of ethyl acetateethyl acetate is above 99. 5%. From figure 5 we canethanol-water. CN: 1526692Gu ZG. Zhi Hz. Ma ZF and Yconclude when glycerol and water quantities is inillation of ethyl Acetate- Ethanol-Wateputers and Appliedcreased 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1,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文献标识码:A文章编号:10014160(2005)06466468中国煤化工CNMHG收稿日期:20050428;修回日期:200506-11发明专利:cN526692A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。