表面活性剂插层水滑石负载纳米钯催化剂的制备及催化Suzuki偶联反应的研究

Preparation of Surfactant Intercalated Hydrotalcite Supported Nanopalladium Catalyst and Research on Suzuki Coupling Reaction Catalyzed by It

采用沉淀-水热法制备了表面活性剂(十二烷基硫酸根)插层的水滑石负载纳米钯催化剂,通过XRD、ICP-AES、XPS、TG、氢气脉冲吸附等分析手段对催化剂晶型结构、形貌及金属分散度进行了表征,考察了用十二烷基硫酸根插层水滑石后负载钯制备的催化剂在不同碱、溶剂、溶剂与水比例、时间、温度、催化剂用量等条件下对Suzuki偶联反应的影响。实验结果表明,插层后的水滑石结构并没有改变,催化剂催化活性显著提高。反应的最佳条件为:碱为氢氧化钾、溶剂为甲醇、与水比例为1:1、温度为50℃、时间为60min、催化剂用量为1.75×10-3mmol,催化剂在重复使用第三次时,产物收率仍可保持在95%以上。

Surfactant intercalated hydrotalcite supported nanopalladium catalysts were synthesized via precipitation-hydrothermal method.The crystal form,morphology and metal dispersion degree of above-prepared catalysts were characterized by X-ray diffraction（XRD）,inductively coupled plasma-atomic emission spectrometry（ICP-AES）,X-ray photoelectron spectroscopy（XPS）,thermogravimetry（TG）,and hydrogen pulse adsorption.The influences of intercalation on catalytic activity of the prepared catalyst in Suzuki coupling reaction under various conditions were investigated,such as different bases,solvents,ratio of solvents to water,time,temperature and catalyst dosage,etc.The results of Suzuki coupling reaction demonstrated that the structure of hydrotalcite was not changed and the catalytic activity was enhanced by surfactant intercalation.The optimal reaction conditions were showed as follows： methanol/H2O（1∶1） and K2CO3 were used as the solvent and base respectively,the temperature was 50℃,time was 60min and the catalyst dosage was 1.75×10-3mmol.The product yield could maintain more than 95% after the catalyst was reused for 3 times.