离子液体催化2-氯噻吩氯甲基化反应研究

Study on Chloromethylation of 2-chloro-thiophene Catalyzed by Ionic Liquids

摘要:

本文以2-氯噻吩、多聚甲醛为原料，以离子液体[C2mim]Br、[C3mim]Br、[C4mim]Br、[C5mim]Br、[C6mim]Br、[C7mim]Br、[C8mim]Br、[C12mim]Br、[Bmim]PF6、[Bmim]BF4、[Bmim]C4F9SO3 和[Bmim]Cl为催化剂进行氯甲基化反应，得到产物2-氯-3-氯甲基噻吩。研究表明，离子液体可以促进2-氯噻吩的氯甲基化反应，具有相转移催化剂的效果，并且以[C4mim]Br和[C8mim]Br的催化效果为佳。通过对反应条件的考察，确定2-氯噻吩氯甲基化反应最佳条件为：催化剂离子液体 [C8mim]Br用量5%，温度40℃，反应时间8h，产物收率可达92.1%。用离子液体催化2-氯噻吩氯甲基化反应，具有催化剂用量少，产品收率较高，产物易分离的特点。

Abstract:

The chloromethylation of 2-chloro-thiophene and paraformaldehyde to 2-chloro-3-chloromethyl-thiophene in the catalysis of different ionic liquids，[C2mim]Br，[C3mim]Br，[C4mim]Br，[C5mim]Br，[C6mim]Br，[C7mim]Br，[C8mim]Br，[C12mim]Br，[Bmim]PF6，[Bmim]BF4，[Bmim]C4F9SO3 and [Bmim]Cl was studied. The result showed that as a phase transfer catalyst ionic liquid could promote the chloromethylation of 2-chloro-thiophene. [C4mim]Br and [C8mim]Br had best catalytic activities. The influence factors, such as the dosage of catalyst, reaction temperature, reaction time and the amount of paraformaldehyde were discussed. Under the best conditions, the dosage of catalyst [C8mim]Br was 5%, 40癈, 8h, good yield was got in 92.1%. The chloromethylation of 2-chloro-thiophene promoted by ionic liquids is with the characteristic of few catalyst, high yield and easy products separation.