固体酸催化合成二氯乙酸乙酯

Synthesis of ethyl dichloroacetate catalyzed by solid acid

介绍一种二氯乙酸乙酯的合成方法．以二氯乙酸为起始原料，研究了催化剂对二氯乙酸与乙醇脱水醚化反应的催化性能，同时讨论了不同带水剂苯、甲苯、环己烷及其用量对反应的影响，得到以FeCl3＆#183;6H2 O为催化剂，环己烷为带水剂，乙醇既作反应原料又为溶剂，制备二氯乙酸乙酯，最佳反应条件：二氯乙酸12．9 g，无水乙醇20 mL，环己烷15 mL，催化剂用量0．5 g，反应温度：回流，反应时间40 min．反应产物蒸馏收集153～156℃的馏分得到无色液体二氯乙酸乙酯，纯度大于98％，蒸干溶剂后，进行催化剂重复使用试验，其结果为：重复反应4次，累计反应时间为240 min，二氯乙酸乙酯产率分别为85．4％，77．1％，83．4％，78．3％．

One kind of method was introduled for the synthesis of dichloro -acetic acid ethyl ester. Dichloroacetic acid was used as staring material,the catalysis of the catalyst on dehydration of dichloroacetic acid and ethanol to produce the ether was discussed.At the same times,The effects of different water-carrying agent such as benzene,toluene,cyclohexane and their dosage on the reaction were investigated.Taking FeCl3＆#183;6H2O as catalyst,cyclohexane as dehydrant,ethanol as reaction solvent and raw materials,dichloro-acetic acid ethyl ester was product.The best reaction condition was as follows：12.9 g dichloroacetic acid,20 ml dehydrated alcohol,15 ml cyclohexane,0.5 g ferric trichloride,reaction temperature was reflux ,reaction time was 40 min. After the reaction was finished ,distilling and collecting 153 ~156 ℃ distillation to get dichloro -acetic acid ethyl ester of a colourless liquid.The yield was 85 .4% and the purity is greater than or equa 98%.After the solvent was distilled,the catalyst was reused total 240 mins.The dichloro-acetic acid ethyl ester productivities of four tests are as follows respectively：85.4%,77.1%,83.4%,78.3%.