Intensifying esterification reaction between lactic acid and ethanol by pervaporation dehydration using chitosan-TEOS hybrid membranes
Intensifying esterification reaction between lactic acid and ethanol by pervaporation dehydration using chitosan-TEOS hybrid membranes
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DOI：
10.1016/j.cej.2009.07.044
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发表时间：
2009-12-15
影响因子：
15.1
通讯作者：
Jiang, Zhongyi
中科院分区：
文献类型：
--
作者：
Ma, Jing;Zhang, Minhua;Jiang, Zhongyi
渗透汽化分离辅助的酯化反应可以选择性地从反应混合物中脱除水分，从而提高用于热力学或动力学受限反应的酯的产率。在Amberlyst 15离子交换树脂的催化下，通过正硅酸乙酯(TEOS)在壳聚糖(CS)水溶液中的原位水解和缩合反应制备了有机-无机杂化膜，用于乳酸和乙醇的渗透汽化酯化反应。用FT-IR、X射线衍射仪、热重分析和接触角等测试手段对CS-TEOS杂化膜的组成和结构进行了研究。通过对乙醇水溶液的渗透汽化实验，评价了杂化膜的脱水性能。与CS原膜相比，CS-TEOS杂化膜具有显著的渗透汽化性能。渗透汽化辅助酯化反应结果表明，采用渗透汽化过程优先脱除反应混合物中的水分，可将乳酸乙酯的产率从66wt.%提高到80wt.%。考察了铸膜液配方、反应温度、乙醇与乳酸的初始摩尔比、催化剂负载量等因素对过程性能的影响。(C)2009爱思唯尔B.V.保留所有权利。
Esterification assisted by pervaporation separation can enhance the yield of ester for thermodynamically or kinetically limited reaction via selective removal of water from the reaction mixture. In the present study, organic-inorganic hybrid membranes were prepared by in situ hydrolysis and condensation of tetraethoxysilane (TEOS) within chitosan (CS) aqueous solution for pervaporation-assisted esterification of lactic acid with ethanol, catalyzed by Amberlyst 15 ion-exchange resin. The composition and structural properties of CS-TEOS hybrid membranes were investigated by FT-IR, XRD, TGA and contact angle. The dehydration performances of hybrid membranes were evaluated by pervaporation of aqueous ethanol solution. Comparing with CS pristine membrane, CS-TEOS hybrid membranes exhibited remarkably enhancing pervaporation property. Pervaporation-assisted esterification results suggested that the incorporation of pervaporation process to preferentially remove water from the reaction mixture substantially enhanced the yield of ethyl lactate from 66 wt.% to 80 wt.%. The effects of membrane casting solution recipe, reaction temperature, initial molar ratio of ethanol to lactic acid and catalyst loading amount on the process performance have been examined in detail. (C) 2009 Elsevier B.V. All rights reserved.