文献类型：期刊文献

英文题名：Gas-phase epoxidation of propylene by molecular oxygen over Ag-CuCl2/BaCO3 catalyst with low CuCl2 doping: Catalytic performance, deactivation and regeneration

作者：Zhang, Qing[1];Chai, Guangtao[1];Guo, Yanglong[1];Zhan, Wangcheng[1];Guo, Yun[1];Wang, Li[1];Wang, Yunsong[1];Lu, Guanzhong[1]

机构：[1]East China Univ Sci & Technol, Sch Chem & Mol Engn, Res Inst Ind Catalysis, Key Lab Adv Mat, Shanghai 200237, Peoples R China

年份：2016

卷号：424

起止页码：65

外文期刊名：JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

收录：;EI(收录号：20163502752162);WOS:【SCI-EXPANDED(收录号:WOS:000386739300008)】；

基金：This work was supported by National Basic Research Program of China (2013CB933200) and Commission of Science and Technology of Shanghai Municipality (15DZ1205305).

语种：英文

外文关键词：Epoxidation of propylene; Propylene oxide; Molecular oxygen; Ag-based catalyst; CuCl2 doping

摘要：Ag-MClx/BaCO3 catalysts with different chloride promoters, prepared by reduction-deposition impregnation method, were investigated for gas-phase epoxidation of propylene to propylene oxide (P0) by molecular oxygen. Ag-CuCl2/BaCO3 catalyst with 360 ppm of Cu and 400 ppm of Cl exhibits the best initial catalytic performance, in which PO selectivity of 71.2% and propylene conversion of 1.3% are achieved, but only PO selectivity of 13.9% is obtained at propylene conversion of 3.2% after reaction for 500 min. The catalytic reaction mechanism over Ag-CuCl2/BaCO3 catalyst follows Rideal-Eley mechanism, in which propylene in the gas phase reacts with molecular oxygen species adsorbed on the surface of Ag at the interface in close contact with CuCl2 to produce PO, and with atomic oxygen species adsorbed on the surface of Ag nanoparticles to produce CO2 and H2O. One oxygen atom of molecular oxygen species reacts with propylene to form a PO molecule, and the left insufficient oxygen atoms react with propylene to produce oxygen-containing intermediates and then to form coke deposition which covers the active sites and thus results in the catalyst deactivation. The deactivated Ag-CuCl2/BaCO3 catalyst can be completely regenerated by combustion of coke deposition and then impregnation with appropriate amount of Cl. (C) 2016 Elsevier B.V. All rights reserved.