苯并三氮唑取代吡啶钴配合物的合成及催化丁二烯聚合行为

Synthesis and 1,3-butadiene polymerization behavior of cobalt complexes containing benzotriazole-substituted pyridine ligands

合成了苯并三氮唑取代吡啶配体的钴配合物,研究了助催化剂种类、取代基结构及聚合温度和时间对1,3-丁二烯聚合的影响。结果显示,经甲基铝氧烷活化后,配合物表现出较高的催化丁二烯聚合活性。配合物的活性取决于配体上吡啶2-位的取代基,其体积的增大导致活性降低,但与聚合物的顺式-1,4-结构选择性并无明显关联。其中,取代基为氢的钴配合物的活性和顺式-1,4-结构选择性最高,可制备出顺式-1,4-结构摩尔分数为94.0%、数均分子量达124.8×10^(3)g/mol、分子量分布窄(多分散性指数2.0)的聚丁二烯。升高反应温度可明显提高聚合速率,在80℃的高温下聚合物收率仍可达93.6%,表明该催化剂体系具有很高的热稳定性。

A series of cobalt complexes contai-ning benzotriazole-substituted pyridine ligands were synthesized.The effects of the type of cocatalyst,substituent structure,and polymerization temperature and time on 1,3-butadiene polymerization were investigated.The results showed that after activation by methylaluminoxane,these complexes exhibited medium to high activities for 1,3-butadiene polyme-rization.The activity of the complex depended on the substituent at 2-position of pyridine on the ligand.An increment of the bulkiness of substituent resulted in a decrease in activity,but it was not significantly related to the cis-1,4-selectivity of the polymer.Among them,cobalt complex with hydrogen substituent group showed the highest activity and cis-1,4-selectivity,affording polybutadiene with predominant cis-1,4-unit mole fraction of 94.0%,a number average molecular weight of 124.8×10^(3) g/mol,and a narrow molecualr weight distribution(polydispersity index 2.0).Raising the reaction temperature could significantly increase the polymerization rate,even at a high temperature of 80℃,the polymer yield remained up to 93.6%,implying the high thermal stability of the catalyst system.