乙烯环氧化反应中铼的助催化机理  

Promoting Effect of Re for Ethylene Epoxidation

作　　者：袁晓红[1] 张式[1] 杨军[2] 邓景发[2] 

机构地区：[1]上海石油化工研究院,上海201208 [2]复旦大学化学系,上海200433

出　　处：《石油化工》1993年第5期293-298,共6页Petrochemical Technology

摘　　要：采用电解银表面化学修饰法研究了铼对乙烯环氧化反应的助催化作用。从修饰后银表面吸附态氧热脱谱(TDS)和氧吸附功函数(ΔΦ)值的变化探讨了铼的助催化机理,认为铼促使吸附态原子氧(Q_a)迅速扩散入Ag表层,形成较多的溶解氧(O_d),有利于乙烯氧化成环氧乙烷,即铼改变了环氧化主副反应的比例,导致含铯银催化剂加铼后具有更高的环氧乙烷选择性。其作用与αα-Al_2_O_3负载的Ag-Re和Ag-Re-Cs催化剂的作用相一致。The promoting effect of Re for ethylene epoxidation was investigated on Re modified electrolytic silver surface. From the peculiar characters of the TDS of oxygen adsorption on this modified Ag surface and the change in the value of oxygen adsorption work function, the mechanism of the promoting effect of Re may be explained. Remakes adsorbed surface atomic oxygen(O_a) diffuse more readily into Ag subsurface forming more dissolved oxygen(O_d), thus favouring the conversion of ethylene to ethylene oxide(EO). Re alters relative extent of main and side reac-tions of epoxidation reaction, and in combination with the action of Cs, leads to a higher selectivity for ethylene oxide. These effects are in consistent with those of α-Al_2O_3 supported Ag-Re and Ag-Cs-Re catalysts.

关 键 词：银 环氧乙烷 乙烯 环氧化反应 铼 

分 类 号：TQ223.26[化学工程—有机化工]