环戊烯开环聚合中的高效活化剂——多卤代苯酚

本文研究了苯酚、卤代苯酚和多卤代苯酚对 WCl_6-i-Bu_3Al 催化体系在环戊烯开环聚合中的活化效果。实验结果表明:(1)在苯环上至少有两个取代的氯原子的苯酚在芳烃中才能具有高活化作用;在烷烃中至少要有三个取代的氯原子的苯酚,如2,4,6-三氯苯酚、2,3,4,6-四氯苯酚和五氯苯酚,其活化效果才更显著。(2)在无活化剂或活化效果较差的苯酚和一溴苯酚存在下,溶剂效应次序:氯苯>甲苯(苯)>加氢汽油(庚烷、环已烷);在活化效果高的多卤代苯酚存在下,溶剂效应不显现。(3)比较了三种卤代烷基铝的助催化效果,其助催化活性次序:Et_2AlI>Et_2AlCl>Et_2AlBr。(4)双烯烃对环戊烯开环聚合有一定的调聚作用。在实验条件下聚合物反式链节含量没有明显改变。

HIGHLY EFFECTIVE ACTIVAT ORS-POLYHALOPHENOLS IN THE RING-OPENING POLYMERIZATION OF CYCLOPENTENE

The activation effect of various polyhalophenols on the ring-opening polymerization of cyclopentene with WCl6-i-Bu3Al catalyst has been investigated. Experimental results showed that 2, 4, 6,-trichlorophenol, 2, 3, 4, 6-tetrachlorophenol and pentachlo-rophenol are highly effective activators in the ring-opening polymerization of cyclopentene to trans polypentenamer in petroleum ether. In the absence of the activator or in the presence of the phenol the six solvents have the effects on the catalytic activity in the following order: chlorobenzene > toluene (benzene) > petroleum ether (heptane, cyclohexane). The cocatalytic activity of three diethylaluminium halides is in the following order: Et2AlI > Et2AlCl > Et2AlBr. The trans-vinylene content of polypentenamer is not affected by the nature of polyhalophenols, solvents and aluminium alkyls, and the polymerization conditions.