丙烯直接环氧化Au/TiO_2催化剂失活及再生研究  

Research on the Deactivation and Regeneration of Au/TiO_2 Catalyst for the Direct Epoxidation of Propylene

作　　者：原宇航[1] 钱刚[1] 吴魏[1] 周兴贵[1] 袁渭康[1] 

机构地区：[1]华东理工大学化学工程联合国家重点实验室,上海200237

出　　处：《分子催化》2005年第3期199-203,i002,共6页Journal of Molecular Catalysis(China)

基　　金：国家自然科学基金资助项目(20276018);上海市重点学科资助项目.

摘　　要：采用沉积沉淀法制得Au/TiO2负载型催化剂,研究了该催化剂的丙烯气相直接环氧化合成环氧丙烷的反应性能,对新鲜、失活和再生后的催化剂进行TG-DTA、FT-IR、吡啶-IR、TEM以及活性评价等表征.研究结果表明,催化剂的失活是由于吸附在催化剂表面酸性Ti位上的环氧丙烷产物发生副反应生成了大分子沉积物.该沉积物存在着两种类型,其含有长碳烷基和酯基.催化剂再生实验表明在空气和H2中再生时活性恢复良好,而在N2中的再生效果则很差.Direct gas-phase epoxidation of propylene to PO in the presence of oxygen and hydrogen over the gold catalyst is an environmentally friendly process. In this paper, Au/TiO_2 catalysts were prepared by the deposition-precipitation method. Fresh, deactivated and regenerated catalysts were characterized by HRTEM, FT-IR and DTA-TG. Results show that the fast deactivation of Au/TiO_2 can be attributed to the deposition of some organic by-products on the catalyst. The deposit contains long-chain alkyl and ester groups. The activity of the catalysts can be fully restored after regeneration in air at 300 ℃; Regeneration in H_2-N\-2 also can restore more than 95% of activity, indicating that H_2 contributes to the desorption of the deposit; However, it was found that pure N_2 plays poor role in the regenertion of deactivated catalysts, and only less than 50% of activity can be restored even under a high temperature of 500 ℃.

关 键 词：环氧丙烷 环氧化 丙烯 金催化剂 失活 再生 

分 类 号：O643.32[理学—物理化学]