双核单茂钛催化苯乙烯间规聚合反应

二十世纪八十年代,Ishihara等人首次使用钛/甲基铝氧烷(MAO)催化体系成功地制备了间规聚苯乙烯(sPS)[1].此后,由于sPS具有结晶速度快,熔点达270℃,赋予了sPS不同于一般聚苯乙烯的优良性能,因此研制新型的苯乙烯间规聚合催化剂成为国内外的研究热点之一.以往的研究主要集中于催化剂活性的提高,因为单核催化剂只是单一的活性中心,所以只能制备窄分子量分布(MWD)的sPS.近年来,为了提高sPS的加工性能和拓宽sPS的分子量分布,人们使用了不同的茂金属混合物[2,3]或者Z iegler-Natta催化剂的氢化物和单一的茂金属进行了诸多尝试[4,5].至今,…     

SYNDIOSPECIFIC POLYMERIZATION OF STYRENE WITH Ar[O,O/NH]Cp*TiCl ACTIVATED WITH MMAO

A series of titanium complexes Ar[O,E]Cp~*TiCl(Cp~*=C_5Me_5,Ar=1,2-phenylene,E=NH(1a);Ar=1,2- phenylene,E=O(1b);Ar=2.2'-diphenylene,E=O(1c);Ar=2,2'-dinaphthalene,E=O(1d)) has been prepared by the reaction of corresponding phenol derivatives with Cp~*TiCl_3 in the presence of excessive triethylamine.Under the conditions of low Al/Ti molar ratio(e.g.500) and high reaction temperatures(>70℃),all the titanium complexes display higher catalytic activities towards the syndiospecific polymerization of styrene,i...