离子液体中芳香硝基化合物羰基化合成硫代氨基甲酸酯

Synthesis of Thiocarbamates by Carbonylation of Aromatic Nitro-compounds in Ionic Liquid

研究了在离子液体1-丁基-3-甲基咪唑六氟磷酸盐([bmim]PF6)中,Pd-Fe/TiO2催化芳香硝基化合物与硫醇或硫酚的羰基化反应,考察了不同反应介质、Pd和Fe负载量(质量分数,下同)、硝基化合物与硫醇的摩尔比、催化剂用量和反应温度对羰基化反应的影响。结果表明,Pd和Fe负载量分别为0.5%和0.3%的Pd-Fe/TiO2催化剂在离子液体[bmim]PF6中对羰基化反应具有很高的催化活性,在硝基化合物10 mmol,醇或酚11 mmol,催化剂36 mg,离子液体10 mL,CO压力0.1 MPa,反应温度30℃,反应时间3～8 h的条件下,一系列芳香硝基化合物和硫醇或硫酚能顺利进行羰基化反应,大多数底物以较好的收率得到相应的硫代氨基甲酸酯。催化剂和离子液体回收简单,重复使用6次后,硫代氨基甲酸酯的收率无明显降低。

An effective carbonylation of aromatic nitro-compounds with thiols or thiophenols catalyzed by Pd-Fe/TiO2 in the ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate（[bmim]PF6） was investigated.The influences of reaction medium,Pd and Fe loading,molar ratio of nitro-compound to thiols,catalyst dosage and reaction temperature on the carbonylation reactions were investigated.The Pd-Fe/TiO2 catalyst with the mass fraction of Pd 0.5% and the mass fraction of Fe 0.3% exhibits a high activity for the carbonylation reactions.The carbonylation of some aromatic nitro-compounds with thiols or thiophenols catalyzed by Pd-Fe/TiO2 in the ionic liquid can proceed well to thiocarbamates in a good yield under the conditions of nitro-compound 10 mmol,thiols or thiophenols 11 mmol,catalyst dosage 36 mg,ionic liquid 10 mL,CO pressure 0.1 MPa,reaction temperature 30 ℃,reaction time 3～8 h.The catalyst and the ionic liquid can be reused for six times without any significant decrease in the yield of thiocarbamates.