多孔SiO_2·xH_2O负载RuB纳米粒子催化喹啉加氢反应

Catalytic Performance of Porous SiO_2·xH_2O Supported RuB Nanoparticles for the Hydrogenation of Quinoline

通过水解,聚乙烯吡咯烷酮(PVP)保护,NaOH刻蚀等方法制备了多孔及富含表面羟基的SiO2·xH2O负载的RuB催化剂RuB/SiO2·xH2O,并用X射线衍射(XRD)、X射线光电子能谱(XPS)、透射电子显微镜(TEM)、傅里叶变换红外(FT-IR)光谱和BET(Brunauer-Emmett-Teller)等手段对该催化剂进行了表征.结果表明该催化剂具有良好的抗中毒能力,在3.0MPa的H2压力和80℃的温和反应条件下,喹啉的转化率高于95%,生成1,2,3,4-四氢喹啉的选择性高于97%.并系统研究了表面羟基和溶剂对催化剂性能的影响,发现以水为溶剂时,RuB/SiO2·xH2O对喹啉加氢反应展示出较高的活性和对1,2,3,4-四氢喹啉较高的选择性,催化剂能够多次循环使用.这一体系的优异催化性能归属于载体表面羟基和水的协同作用.

A porous and hydroxyl group-rich catalyst RuB/SiO2·xH2O was prepared by hydrolyzing ethyl silicate,protecting SiO2·xH2O with polyvinyl pyrrolidone（PVP）,and etching SiO2·xH2O with NaOH.The catalyst was characterized by X-ray diffraction（XRD）,X-ray photoelectron spectroscopy（XPS）,transmission electron microscopy（TEM）,Fourier transform infrared（FT-IR） spectroscopy,and BET（Brunauer-Emmett-Teller）.We found that the catalyst showed excellent performance for the hydrogenation of quinoline under mild condition.At a hydrogen pressure of 3.0 MPa and a reaction temperature of 80℃,the conversion of quinoline reached 95% and the selectivity for 1,2,3,4-tetrahydroquinoline was 97%.This porous catalyst also showed an excellent anti-poisoning characteristic.The catalyst can be reused several times.We also investigated the effect of surface hydroxyl groups and the solvent on catalytic activity and selectivity.The results showed that using water as a solvent leads to higher catalyst activity and selectivity for the hydrogenation of quinoline.The mechanism of quinoline hydrogenation over the catalyst is discussed.The coordination of the nitrogen on quinoline onto the surface of ruthenium nanoparticles,the effect of hydrogen bond among the surface hydroxyl groups of the catalyst and the nitrogen present in quinoline and in the water solvent were favorable for the adsorption of the substrate and the desorption of the products from the surface of the catalyst.