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

摘要:

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、硝基化合物与硫醇物质的量比、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，催化剂用量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。

Abstract:

A effective carbonylation of aromatic nitro-compounds with thiols or thiophenols catalyzed by Pd-Fe/TiO2 in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) was studied. 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. Pd-Fe/TiO2 catalyst with mass fraction of Pd 0.5% and mass fraction of Fe 0.3% exhibits high activity for carbonylation reactions. The carbonylation of some aromatic nitro-compounds with thiols or thiophenols catalyzed by Pd-Fe/TiO2 in ionic liquid can proceed well to thiocarbamates in 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 ionic liquid can be reused for six times without significant decrease in the yield of thiocarbamates.