Cp_2TiR(OMe)/AlEtCl_2体系催化乙烯-丙烯共聚合

ETHYLENE PROPYLENE COPOLYMERIZATION CATALYZED BY Cp 2TiR(OMe)/AlEtCl 2 SYSTEM

由双环戊二烯基钛取代环丁烷化合物经与甲醇反应得到的Ｃｐ２ＴｉＲ（ＯＭｅ）作为主催化剂，在烷基铝存在下催化乙烯与丙烯共聚合，研究了助催化剂种类、铝钛比和单体比对催化活性的影响．结果表明，含氯的烷基铝能有效促使主催化剂呈现活性．根据共聚物组成与单体组成的关系测得两种单体的竞聚率为ｒＥ＝５３，ｒＰ＝００３，ｒＥｒＰ＝０１６，表明该体系为无规共聚合．用１３ＣＮＭＲ测定共聚物的序列结构分布，结果表明丙烯链节大部分是孤立存在的，被乙烯链节或链段所分隔．

Cp 2TiR(OMe) prepared by treating bis( η 5 cyclopentadienyl)titanacyclobutane compound with one equivalent of methanol was used as a catalyst precursor in the copolymerization of ethylene and propylene in the presence of AlEtCl 2. The effects of the type of alkylaluminum, molar ratio of alkylaluminum to the titanocene and monomer composition on the catalytic activity for the copolymerization were studied. It was found that chlorine containing alkylaluminums are the efficient co catalysts. The monomer reactivity ratios of the copolymerization catalyzed with Cp 2TiR(OMe) AlEtCl 2 catalyst system were estimated to be r E=5 3, r P=0 03 and r E r P=0 16, indicating a random copolymerization. The 13 C NMR analysis of the sequence distribution of copolymer indicated that the propylene units in copolymer are mostly isolated by ethylene units or ethylene homopolymeric sequences.