导电聚合物单体3,4-乙烯二氧噻吩的合成

Synthesis of Electroconductive Polymers Monomer 3,4-Ethylenedioxythiophene

以硫代二甘酸为起始原料,经过五步反应得到产物3,4-乙烯二氧噻吩(EDOT),过程如下:首先在浓硫酸催化条件下,硫代二甘酸与甲醇酯化生成硫代二甘酸二甲酯,产率为93.2%;产物进而与草酸二乙酯反应后得到3,4-二羟基噻吩-2,5-二甲酸二甲酯,产率为92.0%;然后经O-烷基化反应,反应中加入四丁基溴化铵作为相转移催化剂,得到3,4-乙烯二氧噻吩-2,5-二羧酸二甲酯,再经水解得到3,4-乙烯二氧噻吩-2,5-二甲酸;在DMSO为溶剂、氮气保护条件下,3,4-乙烯二氧噻吩-2,5-二甲酸在碱式碳酸铜催化作用下脱去两分子CO2得到终产物EDOT。本方法中间产物及终产物的结构经由IR证实,并经过GC含量分析,总收率为34.6%。

3,4-Ethylenedioxythiophene（EDOT） is synthesized using thiodiglycolic acid as starting mate- rial via five reactions. Firstly, thiodiglycolic acid reactes with methanol to synthesize thiodiglycolic acid dimethyl ester by esterify reaction with strong sulfuric acid catalyzer,the yield is 93.2% ;product reaetes with diethyl oxalate to synthesize 3,4- dihydrothieno-2,5 -dicarboxylie acid dimethyl ester by Claisen condensation reaction, the yield is 92.0%, then 3,4 - dihydrothieno - 2,5 - diearboxylic acid dimethyl ester via the step of O -alkylation reaction and use tetrabutyl ammonium bromide for phase transfer cata- lyst, to get 3,4 - ethylenedioxythiophene - 2,5 - dicarboxylic acid dimethyl ester, which to hydrotyze to give 3,4 - ethylenedioxythiophene - 2,5 - dicarboxylic acid ; 3,4 - ethylenedioxythiophene - 2,5 - dicar-boxylic acid take away two molecule of CO2 to get the final product EDOT in DMSO solvent, N2 protect and cubrie carbonate catalyze. Structures of intermediate products and final products are characterized by IR spectra and determined assay by GC,the total yield is 34.6%.