丙烯在Au/TiO_2催化剂上的化学吸附与临氢环氧化反应  

Chemsorption of Supported Au/TiO_ 2 Catalyst in Direct Epoxidation of Propylene

作　　者：孙菲菲[1] 钟顺和[1] 

机构地区：[1]天津大学化工学院

出　　处：《应用化学》2003年第9期849-852,共4页Chinese Journal of Applied Chemistry

基　　金：国家自然科学基金资助项目 ( 2 0 0 760 3 5 )

摘　　要：沉积沉淀法制得Au/TiO2 催化剂 ,采用化学吸附 IR、化学吸附 TPD与微反技术研究了Au/TiO2 的化学吸附性质和丙烯临氢环氧化反应性能。丙烯分子中CC键上的π电子与催化剂表面的Lewis酸位Tin + 作用 ,形成d π配键。环氧丙烷以碳氧三元环上的O吸附在Au/TiO2 催化剂表面的Tin + 位上 ,O的孤对电子进入Tin + 的空d轨道 ,形成配位键。Au粒子吸附活化O2 与H2 ,将其转变为吸附在其上的过氧化物H2O2 物种。丙烯吸附在Tin + 位并活化后 ,与吸附在Au粒子上的过氧化物物种相互作用 ,被氧化为环氧丙烷。The supported catalyst Au/TiO 2 was prepared by deposition-precipitation method. Chemsorbility of the catalyst was studied by in situ IR and TPD techniques and activity of the catalyst was tested in a micro- reactor. The results revealed that propylene is chemisorbed on Lewis acid sites Ti n+ on the surface of Au/TiO 2 through CC bond and newly formed propylene oxide is chemisorbed on Ti n+ through the oxygen of its epoxy ring. The selectivity of propylene oxide in propylene epoxidation over Au/TiO 2 is 93% and conversion of propylene is 0.76%. Au nano-particles adsorb H 2 and O 2 and transform them into peroxide species, which diffuse to Ti site, leading to the formation of propylene oxide.

关 键 词：AU/TIO2 环氧丙烷 丙烯环氧化 

分 类 号：O643[理学—物理化学]