文献类型：期刊文献

英文题名：Steric and electronic effects of the R in IndTiCl₂(OR) catalysts on the syndiospecific polymerization of styrene

作者：Ma, HY; Chen, B; Huang, JL; Qian, YL

机构：[1]E China Univ Sci & Technol, Organomet Chem Lab, Shanghai 200237, Peoples R China

年份：2001

卷号：170

期号：1-2

起止页码：67

外文期刊名：JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000168613100007)】；

语种：英文

外文关键词：syndiotactic polystyrene; titanocene; alkoxyl ligand; steric and electronic effects

摘要：Four alkoxyl ligand substituted indenyl titanium dichloride complexes, IndTiCl(2)(OR) (R = Me (2), Et (3), Pr-i (4), cyclohexyl (5)) were prepared, and evaluated as catalysts for the syndiospecific polymerization of styrene when activated with methylaluminoxane (MAO). Alkoxyl ligand substituted complexes showed higher catalytic activities than IndTiCl(3) (1) except for complex 5. When R = Et, the catalyst 3 showed the highest activity. A study of the steric and electronic effects of alkoxyl ligand revealed that the more electron-donating and less steric bulky R group was more suitable for the improvement of the catalytic activity. When the polymerization was carried in solution at high molar ratio of Al/Ti = 4000, the s-PS% of obtained polymer were in the range of 99.0-99.6%. The highest melting point of 276.9 degreesC was obtained by using 2 as catalyst. The influence of polymerization temperature was also investigated. The maximum polymerization activities were found at 50 degreesC for all of the above complexes, but the percentages of s-PS were insensitive to the polymerization temperature. (C) 2001 Elsevier Science B.V. All rights reserved.