Titanium precatalysts bearing N-substituted β-amino alcohols for 1-hexene polymerization: The effect of steric crowding
Titanium precatalysts bearing N-substituted β-amino alcohols for 1-hexene polymerization: The effect of steric crowding
复制标题
DOI：
10.1016/j.polymer.2006.03.039
复制
发表时间：
2006-05
期刊：
影响因子：
4.6
通讯作者：
K. Vijayakrishna;G. Sundararajan
中科院分区：
文献类型：
--
作者：
K. Vijayakrishna;G. Sundararajan
以氨基醇锂盐为原料，与TiCl 4（THF）2反应，制备了一系列钛基非茂金属预催化剂[2-（2，6-二烷基苯氨基）-1-苯乙氧基] TiCl 2。在用甲基铝氧烷（MAO）活化后，这些预催化剂以全同立构方式聚合1-己烯。催化剂的活性和聚合物的性质取决于配体中苯胺邻位的空间位阻特征。随着苯胺部分邻位烷基的体积增加，催化剂表现出更好的活性，具有高分子量和更大的立构规整度控制。对于1-己烯聚合，预催化剂1ATiCl 2在室温下显示出3.05kg PH/mol·Ti·h的活性，并且所得聚己烯具有403，600（Mw/Mn=1.40）和80%全同立构规整度（mmmm）。二苄基钛配合物1ATi（CH 2 Ph）2和3ATi（CH 2 Ph）2在MAO或Ph 3CB（C6 F5）4的活化下，对1-己烯聚合表现出相对较低的活性，得到分子量较低但分子量分布较窄的聚合物。
A series of titanium-based non-metallocene precatalysts [2-(2,6-dialkylphenylamino)-1-phenylethoxy TiCl2were prepared by reacting lithium salts of the corresponding amino alcohols with TiCl4(THF)2. Upon activation with methylaluminoxane (MAO), these precatalysts polymerized 1-hexene in isotactic manner. The catalyst activity and polymer properties depended on the steric features in the ortho positions of the aniline moiety of the ligands. As the bulkiness of the alkyl group in ortho positions of the aniline moiety increased, the catalyst showed better activity with high molecular weight and greater tacticity control. For 1-hexene polymerization, precatalyst 1ATiCl2showed activity of 3.05kg of PH/mol-Ti.h at room temperature and the resulting polyhexene had molecular weight of 403,600 (Mw/Mn=1.40) with 80% isotacticity (mmmm). The dibenzylic titanium complexes 1ATi(CH2Ph)2and 3ATi(CH2Ph)2, upon activation with MAO or Ph3CB(C6F5)4, showed relatively lower activities towards 1-hexene polymerization, yielding polymers of lower molecular weights but with narrow molecular weight distribution.