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在Ba、Cs、C l促进的Ag/α-A l2O3催化剂上,考察了丁二烯的环氧化反应,获得较高的丁二烯转化率和乙烯基环氧乙烷选择性.在未添加卤代烃致稳剂条件下,催化剂短期稳定性超过140 h.并对反应前后的催化剂进行了XRD、TEM、XPS等晶相和表面分析.XRD结果表明催化剂经短期稳定性试验后,银的平均粒径变化不大,但TEM分析表明在银催化剂的局部有银颗粒的板结;而XPS结果表明催化剂表面C l有流失,Cs有富集.Cs-Ag的相互作用有可能促进吸附于Cs-A l活性位的氧物种插入吸附于Ag上的丁二烯.
On the Ba, Cs, C l promoted Ag / α-Al 2 O 3 catalysts, the epoxidation of butadiene was investigated to obtain higher butadiene conversion and ethylene oxide selectivity. Under the condition of adding halogenated hydrocarbon, the short-term stability of the catalyst was over 140 h, and the XRD, TEM, XPS and other phase and surface analysis of the catalyst before and after the reaction were carried out.XRD results showed that after short-term stability test, , But the TEM analysis showed that there was silver particles in the local silver catalyst. XPS results showed that there was a loss of C l on the catalyst surface and enrichment of Cs. The interaction of Cs-Ag may promote the adsorption of Cs-Al active species of oxygen species insert butadiene adsorbed on Ag.