Hu Rui, Yang Pengfei, Pan Yongning, Li Yunpeng, He Yufei, Feng Junting, Li Dianqing
State Key Laboratory of Chemical Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Dalton Trans. 2017 Oct 10;46(39):13463-13471. doi: 10.1039/c7dt02247f.
A highly dispersed CuO catalyst was prepared by the deposition-precipitation method and evaluated for the catalytic epoxidation of styrene with tert-butyl hydroperoxide (TBHP) as the oxidant under solvent acetonitrile conditions. Compared with MgAl hydrotalcite (MgAl-HT)-, MgO-, TiO-, C-, and MCM-22-supported catalysts, CuO/CoAl-HT exhibited preferable activity and selectivity towards styrene oxide (72% selectivity at 99.5% styrene conversion) due to its high dispersion of CuO and surface area of Cu. The improved dispersion of CuO/CoAl-HT could be ascribed to the nature of HT support, especially the synergistic effect of acidic and basic sites on the surface, which facilitated the formation of highly dispersed CuO species. A structure-performance relationship study indicated that copper(ii) in CuO was the active site for the epoxidation and oxidation of styrene, and that Cu of rich electronic density favored the improvement of selectivity of styrene oxide. Based on these results, a reaction mechanism was proposed. Moreover, the preferred catalytic performance of CuO/CoAl-HT could be maintained in five reused cycles.
采用沉积沉淀法制备了一种高度分散的CuO催化剂，并在溶剂乙腈条件下，以叔丁基过氧化氢（TBHP）为氧化剂，对苯乙烯的催化环氧化反应进行了评价。与MgAl水滑石（MgAl-HT）、MgO、TiO、C和MCM-22负载的催化剂相比，CuO/CoAl-HT对环氧苯乙烷表现出较好的活性和选择性（苯乙烯转化率为99.5%时，选择性为72%），这归因于其CuO的高分散性和Cu的表面积。CuO/CoAl-HT分散性的提高可归因于HT载体的性质，特别是表面酸性和碱性位点的协同作用，这促进了高度分散的CuO物种的形成。结构-性能关系研究表明，CuO中的铜（II）是苯乙烯环氧化和氧化的活性位点，富电子密度的Cu有利于提高环氧苯乙烷的选择性。基于这些结果，提出了一种反应机理。此外，CuO/CoAl-HT的优异催化性能在五个重复使用循环中得以保持。
