有机中间体2-溴噻吩的合成研究

Synthesis research of intermediate 2-bromothiophene

分别采用冰乙酸溶剂法、四氯化碳溶剂法、直接溴化法合成了2-溴噻吩,重点考察了加溴方式、加溴时间、原料配比、反应温度等影响因素对直接溴化法生产2-溴噻吩工艺的影响,并对三种生产工艺的生产成本进行了对比分析.实验结果表明:冰乙酸溶剂法和四氯化碳溶剂法不适合工业化生产,而直接溴化法是比较理想的生产工艺.将溴以蒸汽状态通入液体噻吩中进行反应产率较高,且副产物最少.溴是否预热和溴蒸汽通入时间对2-溴噻吩产率影响比较明显;直接溴化法的最佳工艺条件为:原料配比为0.55∶1-0.6∶1;反应温度为65℃-75℃;加溴时间为6-8 h.

2-bromothiophene was synthesized respectively by three methods： acetic acid solvent, carbon tetrachloride solvent and direct bromination. A series of factors such as the style of adding bromine, time of adding bromine, the ratio of materials and the reaction temperature were investigated, which affected the yields of 2-bromothiophene in the direct bromination. And the economic performance of the three production process was compared. Experimental results indicate that the methods of glaeical acetic acid and carbon tetrachloride as solvent are not suitable for industry, but the direct hromination method is the best one. When bromine was added as gas into thiophene, the yield of 2-bromothiophene is higher and there was little by-product. Meanwhile, the key factors effecting on the yield of 2-bromothiophene are the adding time of vaporizing bromine and whether it was warmed-up or not. The optimum conditions of direct bromination are： the ratio of materials is 0.55：1 to 0.6： 1, the reaction temperature is 65 to 75 ℃, and the adding time of bromine is 6 to 8h.