超声辅助还原法制备钯碳催化剂及其催化Suzuki反应的研究

Preparation of Palladium-Carbon Catalyst by Ultrasound Assisted Reduction Method and Study on Its Application in Suzuki Coupling Reaction

以椰壳活性炭为载体,乙二醇为还原剂,超声辅助还原法制备了钯碳催化剂(Pd/C-u)。利用N2物理吸附、X射线衍射分析(XRD)、透射电子显微镜(TEM)等对所制备的Pd/C催化剂进行了结构与形貌的表征,结果表明,钯纳米粒子为面心立方结构,均匀地分布在活性炭表面,平均粒径为6.16nm。当以超声辅助还原法制备Pd/C为催化剂进行对溴甲苯和对溴硝基苯与苯硼酸的Suzuki偶联反应时,在0.1%催化剂用量,60℃下反应30min时,反应收率分别为98.22%和82.08%,高于常规还原法制备的Pd/C-c催化剂。

The palladium-carbon catalyst（Pd/C-u）was prepared by ultrasound assisted reduction with coconut shell-based activated carbons as support, ethylene glycol as reductant. The structure and morphology of as-prepared Pd/C were characterized by N2 physical absorption, XRD and TEM. The results showed that the palladium nanoparticles（Pd NPs） in Pd/C-u had the face-centered cubic structure and a uniform distribution on the surface of activated carbons with an average size of 6.16 nm. When the reaction temperature and time was 60 ℃ and 30 min respectively, the yields of Suzuki coupling reaction of 4-bromotoluene and 1-bromo-4-nitrobenzene with benzeneboronic acid with the 0.1% molar content of Pd/C-u cata-lyst were 98.22%and 82.08% respectively, which were higher than the results of one using catalyst prepared by conventional chemical reduction（Pd/C-c）.