文献类型：期刊文献

英文题名：Gas-phase epoxidation of propylene by molecular oxygen over Ag/BaCO3 catalysts: Effect of preparation conditions

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

机构：[1] Key Laboratory for Advanced Materials, Research Institute of Industrial Catalysis, East China University of Science and Technology, Shanghai, 200237, China

年份：2016

卷号：276

起止页码：2

外文期刊名：Catalysis Today

收录：EI(收录号：20162302463533)

语种：英文

外文关键词：Calcination - Molecular oxygen - Propylene - Catalyst selectivity - Gases - Barium compounds - Amines - Ethylene - Catalysis - Silver

摘要：Ag/BaCO3 catalysts with different Ag crystallite sizes, prepared by the reduction-deposition method, were developed for gas-phase epoxidation of propylene to propylene oxide (PO) by molecular oxygen. Effects of preparation conditions, such as pretreatment of organic amines of BaCO3 support, pretreatment way of ethylene diamine, reduction temperature of HCHO and calcination temperature, on the catalytic performance and Ag crystallite size of Ag/BaCO3 catalyst were investigated. Ag/BaCO3* catalyst, with pretreatment of BaCO3 support by ethylene diamine and prepared at the reduction temperature of HCHO of 10 °C and the calcination temperature of 250 °C, exhibited better catalytic performance and good durability, in which 12.5% of propylene conversion and 36.9% of PO selectivity were achieved under the reaction conditions of 20%C3H6–10%O2–70%N2, 200 °C, 0.1 MPa and GHSV of 3000 h?1. Both lower reduction temperature of HCHO and lower calcination temperature can get smaller Ag crystallite sizes, which is more effective for epoxidation of propylene over Ag/BaCO3* catalyst. The catalytic reaction mechanism of Ag/BaCO3* catalyst for epoxidation of propylene is that propylene in the gas phase reacts with molecular oxygen species adsorbed on the catalyst surface to produce PO and follows Rideal–Eley mechanism. ? 2016 Elsevier B.V.