锌/钴双金属氰化物络合物催化剂(DMC)催化环氧丙烷聚合反应的活性结构研究

双金属氰化物络合物 (DMC)是一类环氧化物聚合反应的高效催化剂 1] ,已将其成功地用于高分子量低不饱和度聚醚多元醇的工业化生产 2 ] .合适的有机配体是制备高活性 DMC催化剂的关键因素 .高活性 DMC催化剂是在有机配体存在下 ,由 Zn Cl2 与 K3Co(CN) 6]在水中反应制得的 ,可表示为Zn3Co(CN) 6]2 · x Zn Cl2 · y H2 O· z L,L 是有机配体 ,主要为醇类和醚类物质 3～ 5] .Schuchardt2 ]和Robert3]等曾对 DMC催化环氧丙烷的聚合机理进行过研究 ,但有关催化活性中心的结构及环氧化物与催化剂的作用方式尚未见报道 .本文以…

Studies on the Active Species of Propylene Oxide Polymerization Initiated by Double Metal Cyanide Complex Catalyst

The effects of organic ethers such as diethyl ether, ethylene glycol diethyl ether and diethyl glycol diethyl ether on the structure of double metal cyanide complex catalyst and the structural changes of such catalyst in the process of propylene oxide polymerization were investigated by EXAFS. The results show that Co in all DMC catalysts is still coordinated by six cyanogens, while Zn is coordinated by O atom in organic complex. The more numerous the number of the ether bond, the higher the coordination numbers of O to Zn ion, the more active the catalyst we make. Five or six O atoms coordinated Zn ion may be the real active center in the process of propylene oxide polymerization.