二(2-乙基己基)磷酸酯为配体的钼系催化体系催化异戊二烯聚合(英文)

Synthesis of polyisoprene with Mo-based catalyst liganded by bis(2-ethylhexyl)phosphate

研究了二(2-乙基己基)磷酸酯(简称P)配体对二氯二氧钼/烷基铝(简称Mo/Al)催化体系催化异戊二烯(Ip)聚合规律的影响,考察了P/Mo(摩尔比)对单体转化率的影响,并测定了产物的相对分子质量及其分布,表征了其微观结构。结果表明,在P/Mo为5时催化体系的催化活性最高,单体转化率可达80%以上。在最佳聚合条件,即Al/Mo(摩尔比)为10、Mo/Ip(摩尔比)为4×10-4时,聚异戊二烯(PI)数均分子量为1.29×105,分子量分布指数为3.87,PI的1,4-、1,2-和3,4-结构的摩尔分数分别为54.2%、21.0%和24.8%。

The 1,2- and 3,4-units regulated polyisoprenes（PI） are stable than 1,4-PI owing to less double bond in their main chain, which means that they do not suffer from the oxidative aging easily. Moreover, 1,2- and 3,4-PI possess high wet-skid resistance and low rolling resistance, and thus receive both academic and industrial attentions. Molybdenum- based catalysts have been investigated in the polymerization of butadiene, as a result, the catalyst exhibited high activity and produced amorphous 1,2-polybutadiene （ mole fraction of 1,2-unit more than 80% ） with high relative molecular mass. In this work, MoCl2O2 （simplified as Mo） modified by bis（2-ethylhexyl） phosphate（simplified as P） ligand and activated with Al （i-Bu）3 （simplified as AI） was used for isoprene（Ip） bulk polymerization at 60 ℃ for 24 h.