环氧乙烷水合制乙二醇多相催化剂的最新进展

摘要

乙二醇是一种重要、但我国自给率却长期不高于40％的大宗化工原料.目前工业上生产乙二醇采用的高水比(水和环氧乙烷进料摩尔比)非催化直接水合技术存在能耗高的问题.发展低水比催化水合技术势在必行.立足于催化与失活机制,本文首次详细而深入地介绍了新型树脂类、金属氧化物基、CoⅢ(Salen)基和Sn掺杂的沸石类催化剂,并针对它们各自的缺点提出了改进措施与解决方案.如提出选取新型官能团以及不同长径比碳纳米管、不同层数石墨烯和纳米氧化物为添加剂以提升离子交换树脂的活性、耐热性和耐溶胀性;合成不同酸度的多孔铌酸材料以提升铌酸催化剂的活性;从有机配体和轴配体两方面出发发展新型CoⅢ(Salen)基催化活性中心以提升CoⅢ(Salen)基催化剂的稳定性;选择不同结构的沸石、采用不同的制备方法和金属源发展多种杂原子沸石以进一步提高现有沸石的活性位点数和活性.本文的阐述有望为发展用于节能降耗工业化生产乙二醇的催化剂提供一定的指引.%Mono ethylene glycol(MEG) is an important bulk chemical,yet the self-sufficiency of which in China is not higher than 40％. The method for producing MEG in industry by non-catalytic direct hydration of ethylene oxide ( EO ) under high molar ratio of water to EO is of high-energy-consumption. Hence,it is urgent to develop catalytic hydration of EO with low molar ratio of water to EO. Herein,based on the catalysis and deactivation mechanism,the newly developed resin-based catalysts,metallic oxide-based catalysts,CoⅢ(Salen)-based catalysts and Sn-doped zeolites were introduced in detail and depth for the first time. Moreover,constructive suggestions for overcoming the disadvantages of these catalysts were proposed. It was advocated that the activity,thermal stability and anti-swelling property of ion-exchange resins could be improved by choosing new functional groups and additives such as carbon nanotubes with various draw ratios,graphene with various layers and kinds of nano oxides. It was suggested that the porous niobic acid materials with different acidity could provide higher activity. For the stability improvement of CoⅢ(Salen)-based catalysts,the development of new CoⅢ(Salen) active species by changing organic ligands and counter-ions could be a good consideration. As for improving the activity and active site number of now-available zeolites,it was reasonable to synthesize kinds of metal-doped zeolites with different framework topologies by different methods and metal sources. It was anticipated that this review would play an instructive role to some extent in developing catalysts for producing MEG with low cost and energy consumption in industry.