环氧丙烷是一种重要的石油化工原料。目前工业上生产环氧丙烷的方法主要有两种:氯醇法和Halcon法。氯醇法对环境造成严重污染,Halcon法又面临联产物的问题。利用分子氧为氧化剂进行丙烯气相催化环氧化是生产环氧丙烷最理想的方法,同时也是催化领域最具挑战性的课题之一,尤其在Cu催化剂上开展丙烯环氧化反应是近年来兴起的1个研究方向,相关报道并不多。本文首先简单介绍了Ag、TS-1/H2O2、Au体系上环氧丙烷绿色合成的研究现状,并分析了各个体系的优缺点和工业化应用前景,然后详细综述了Cu催化剂上丙烯直接氧气环氧化的研究进展,包括Cu催化剂的制备方法、修饰剂的选择、金属助催化剂等对丙烯环氧化性能的影响,并对其前景进行了分析展望。
关键词:
Cu; 丙烯; 环氧化; 氧气; 环氧丙烷
Propylene oxide is one of important building blocks in chemical industry. Until now, the major conventional manufacturing methods of propylene oxide are the chlorohydrin and the Halcon processes. The chlorohydrin process is phase-out due to environmental pollution, while the latter has the byproduct limitation. The most ideal process is the epoxidation of propylene with molecular oxygen as the oxidant to produce propylene oxide; however the reaction remains one of the biggest challenges in the catalysis field. Propylene epoxidation by oxygen on Cu-based catalysts is just beginning, and until now the relative reports are very few. The green catalytic synthesis of propylene oxide on Ag, TS-1/H2O2, and Au is simply introduced. The advantages and disadvantages as well as industrial application prospect of these systems are discussed, respectively. Then, the recent progress in propylene epoxidation by oxygen over Cu catalysts is detail reviewed. The influence of Cu catalysts preparation methods, alkali metal ions promoters, and metal cocatalysts on the catalytic performances of propylene epoxidation by oxygen is outlined. Finally, the prospects in the field are presented.