摘要
以TiCl_4-Al(i-Bu)_3为催化剂室温下进行Ⅰ-十六烯聚合。当Al/Ti比小于1.75时得到了分子量低于5000、每条聚合物链带—个反式内双键的低聚物,而Al/Ti比升高时产物逐渐变为高分子量聚合物。实验表明该催化体系中存在分别产生低聚物和高聚物的两类活性中心。这种产生低聚物的活性中心不同于一般Lewis酸引发的阳离子聚合中心,推测是一种按二级插入机理增长、很易发生β-氢迁移的特殊的配位聚合活性中心。
1-Hexadecene was polymerized at room temperature by TiCl_4-Al(i-Bu)_3 catalyst. At Al/Ti(mole ratio)≤1.75 the polymer has M_n lower than 5000 and each of its chain carries a double bond, while at higher Al/Ti ratio the product has much higher molecular weight(MW). The presence of two kinds of active centers corresponding respectively to the low and high MW products is evidenced. The behavior of the active center producing low MW product does not conform with the conventional cationic active center initiated by Lewis acids. The active center is considered to be of a special type of coordination polymerization which obeys a secondary tnsertion mechanism of propagation and a β-hydrogen shift mechanism of chain transfer.
出处
《石油化工》
CAS
CSCD
北大核心
1992年第11期719-723,共5页
Petrochemical Technology
基金
浙江省自然科学基金
