Polymerization of propylene with the [ArN(CH2)3NAr]TiCl2 (Ar = 2,6-iPr2C6H3) complex using R3Al/Ph3CB(C6F5)4 (R = Me, Et, iBu) as cocatalyst

✍ Scribed by Jizhu Jin; Shingo Tsubaki; Toshiya Uozumi; Tsuneji Sano; Kazuo Soga

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 367 KB
• Volume: 19
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/(sici)1521-3927(19981101)19:11<597::aid-marc597>3.0.co;2-h

✦ Synopsis

Polymerization of propylene was conducted at 0 -150°C with the [ArN(CH2)3NAr]TiClz (Ar = 2,6-'Pr2C6H3) complex using a mixture of ~a l k y l a l u m i n i ~ (AIR3, R = methyl, ethyl and isobutyl) and Ph3CB(C&& as cocatalyst. When AlMe3 or AlEt3 was employed, atactic polypropylene (PP) was selectively produced, whereas the use of Al('Bu)3 gave a mixture of atactic and isotactic PR The isotactic index (1.1.; weight fraction of isotactic polymer) depended strongly upon the polymerization temperature, and the highest 1.1. was obtained at ca. 40°C. The 13C NMR analysis of the isotactic polymer suggests that the isotactic polymerization proceeds by an enantiomorphic-site mechanism. It was also demonstrated that the present catalyst shows a very high regiospecificity.