噻吩-2,3-二羧酸的电合成

Electrosynthesis of Thiophene-2,3-Dicarboxylic Acid

以3-甲基噻吩为原料,通过电卤化、格氏反应、间接电氧化三步合成目标产物噻吩-2,3-二羧酸。考察了电卤化过程中电流密度、温度对2-溴-3-甲基噻吩收率的影响。在此过程中电卤化试剂采用溴化钠,产品收率可达85.5%且能够更好的满足格氏反应中底物活泼性的考究。通过格氏反应合成了3-甲基-2-噻吩羧酸,主要对其反应时间与收率的关系进行了考察,较优反应时间为6 h,产品收率最高达87.8%。以间接电氧化法合成噻吩-2,3-二羧酸,分别考察了电流密度、电解温度、基质氧化温度、投料比、反应时间等因素对反应的影响,较优工艺下收率为87.6%。噻吩-2,3-二羧酸的整个电合成的过程中均无采用传统有毒有害的卤化剂与氧化剂,对环境友好,三废排放少,且过程简单,产物易分离,能够获得较高的产品收率。

Thiophene-2,3-dicarboxylic acid was synthesized from 3-methylthiophene by three steps of electrohalogenation,Grignard reaction and indirect electrooxidation.The effects of current density and temperature on the yield of 2-bromo-3-methyl thiophene during electrohalogenation were investigated.In this process,sodium bromide is used as the electrohalogenating reagent,which not only achieves 85.5% yield,but also can better satisfy the study of substrate activity in Grignard reaction.3-Methyl-2-thiophene carboxylic acid was synthesized by grignard reaction.The relationship between reaction time and yield was investigated.The optimum reaction time was 6 h,and the yield was 87.8%.Thiophene-2,3-dicarboxylic acid was synthesized by indirect electrooxidation method.The effects of current density,electrolytic temperature,matrix oxidation temperature,feed ratio and reaction time on the reaction were investigated.The yield of thiophene-2,3-dicarboxylic acid was 87.6% under the optimum process.The whole process of electrosynthesis of thiophene-2,3-dicarboxharmful halogenating agents and oxidants,which is environmentally friendly,less three wastes discharge,simple process,easy product separation,and can obtain higher products yield.