茂金属催化剂催化苯乙烯间规聚合 Ⅰ.Cp Ti(CH_2SiMe_3)_3/B(C_6F_5)_3催化体系  

SYNDIOSPECIFIC POLYMERIZATION OF STYRENE CATALYZEDBY METALLOCENE CATALYSTSⅠ. Cp*Ti(CH2SiMe3)3/B(C6F5)3 Catalyst

作　　者：Xu Guangxue, Liu Shuiping, Lin Shang′an(Institute of Polymer Science, Zhongshan University, Guangzhou 510275) 

出　　处：《催化学报》1998年第3期284-286,共3页

基　　金：国家自然科学基金

摘　　要：考察了新型催化剂Ｃｐ＊Ｔｉ（ＣＨ２ＳｉＭｅ３）３／Ｂ（Ｃ６Ｆ５）３催化苯乙烯间规聚合的性能．结果表明，Ｃｐ＊Ｔｉ（ＣＨ２ＳｉＭｅ３）３与Ｂ（Ｃ６Ｆ５）３等摩尔混合可形成高活性的催化剂，催化活性高达（０．７～１．３７）×１０７ｇ／（ｍｏｌ２·ｈ），聚苯乙烯的间规度为９５％以上．Ｂ（Ｃ６Ｆ５）３／Ｔｉ摩尔比不等于１时，其催化活性和间规立构选择性都明显降低．Ａｌ（ｉ－Ｂｕ）３的加入不仅显著提高催化活性和间规立构选择性，而且还提高了间规聚苯乙烯的相对分子量．最佳聚合温度为３４３Ｋ．在ｃ（Ｓｔ）＝０．４４～６．５６ｍｏｌ／Ｌ范围内，苯乙烯聚合速率对苯乙烯单体呈一级反应，苯乙烯转化率和间规聚苯乙烯的相对分子量随反应时间的增加而提高．The reaction of Cp*Ti(CH2SiMe3)3 solution with equimolar amount of B(C6F5)3 in hexane/toluene (volumic ratio 5) at 243 K resulted in almost quantitative formation of a new complex [Cp*Ti(CH2SiMe3)2]+[B(CH2SiMe3)(C6F5)3]-, which is identified by elemental analysis, 1H NMR and 13C NMR. The complex was thermally unstable and turned deep yellow liquid at RT. The addition of toluene to CD2Cl2 solution of the complex led to only partial conversion of the complex to [Cp*Ti(CH2SiMe3)2(η6PhMe)]+[B(CH2SiMe3)(C6F5)3]-, identified by 1H NMR. The complex has been investigated by ESR. At RT the formation of Ti(Ⅲ) cation [Cp*Ti(CH2SiMe3)]+ has been observed. The spectroscopic data combined with the polymerization activity measurement suggest that the Ti(Ⅲ) cation is the active species for styrene syndiospecific polymerization.

关 键 词：茂金属 催化剂 苯乙烯 间规聚合 聚苯乙烯 聚合 

分 类 号：TQ325.2[化学工程—合成树脂塑料工业]