镍二亚胺配合物/烷基铝催化乙烯聚合的研究

以3种镍二亚胺配合物和烷基铝组成催化体系进行乙烯聚合,结果发现聚合条件如助催化剂、铝镍摩尔比、聚合温度和配体等对乙烯聚合催化活性有很大影响。空间位阻最小的镍二亚胺配合物NiL1Cl2在以AlEt2Cl为助催化剂、聚合温度14℃、铝镍摩尔比60的条件下对乙烯聚合催化活性达到7.4×105g/(mol·h)(每摩尔Ni生成的聚合物质量)。空间位阻较小的NiL1Cl2和NiL2Cl2配合物乙烯聚合的产物是C4～C18烯烃和少量环烷烃的混合物。空间位阻最大的NiL3Cl2配合物生成的聚乙烯的相对分子质量为294 000,支化度为48％。

Ethylene Polymerization Catalyzed by Nickel Diimine Complexes/Alkylaluminium Catalyst System

Ethylene polymerizations catalyzed by three nickel diimine complexes with alkylaluminum as cocatalyst were studied. Polymerization conditions such as co - catalysts, mole ratios of Al/Ni, polymerization temperature and ligands had substantial effects on catalytic activity. Catalytic activity as high as 7.4 × 105 g/ (mol·h) was achieved by least sterically hindered nickel diimine complex NiL1Cl2.when co - catalyst was AlEt2Cl,mole ratio of Al/Ni 60,and polymerization temperature 14 ℃ . Products produced by two nickel diimine complexes NiL1Cl2 and NiL2Cl2 with medium sterically hindered ligands were mixtures of C4-C18 olefins and with less amount of cycloalkanes. Polyethylene products with Mw of 294 000 and branching degree 48% were obtained by nickel complex NiL3Cl2 with ligands having the most obvious steric hindrance effect.