窄分布聚醚合成用催化剂的制备及性能表征

Fabrication and properties characterization of catalysts for synthesis of polyether with narrow molecular weight distribution

为制备窄分布的聚醚产品,采用共沉淀法合成Mg/Al/Co复合金属氧化物,采用不同配体合成Fe/Zn双金属氰化络合物(DMC)作为催化剂,以正辛醇为起始剂、环氧乙烷为聚合单体合成聚氧乙烯醚.采用SEM和TEM表征催化剂的微观结构,采用薄层色谱法(TLC)分析聚醚产物的分子质量分布,并考察不同催化剂的催化活性以及反应温度对催化活性的影响.结果表明:Mg/Al/Co催化剂具有丰富的孔状结构,而DMC为不规则片状结构,无空隙;同等条件下以1,4-二氧六环为配体的DMC3反应速率是其他催化剂的2.4~3.8倍,具有较高的催化活性;随着反应温度的升高,催化剂的催化活性均先升高后下降,100℃时,催化剂活性最高;Mg/Al/Co催化所得聚醚产品的分子质量分布指数(EDI)可达87.5%,DMC3催化所得产物的EDI指数为86.4%,且催化剂循环使用3次以后催化所得产物的EDI指数均可达到85%以上.

In order to prepare polyether with narrow molecular weight distribution, Mg/Al/Co complex metal oxides（CMO） was prepared by using coprecipitation method and Fe/Zn double metal cyanide （DMC） was prepared by using different ligands. Then polyoxyethylene ether was prepared by using octanol as the starting agent, EO as monomer and CMO, DMC as catalysts. The microstructure of products was characterized by the TEM and SEM. The molecular weight distribution of the polyether was analyzed through thin -layer chromatography （TLC）. Furthermore, the catalytic activity of different catalysts and the effect of temperature on catalytic activity were investigated. The results showed that the abundant pore structure was observed on Mg/Al/Co and layer structures was observed on the DMC 曰 Under the same condition, the reaction rate of DMC3 with 1,4-dioxane as ligand was 2.4-3.8 times that of other catalysts; All of the catalyst activity rose at first and went down latter with reaction temperature increasing, and the optimal temperature was 100 益; The molecular weight distribution index（EDI） of polyether catalyzed by CMO and DMC3 could reach 87.5% and 86.4% , respectively. Moreover, the EDI of polyether could also reach more than 85% after 3 cycles of operation.