Polymerization of propene with the XTiCl3/MgCl2–Al(i-Bu)3 catalyst system (X = cyclopentadienyl, pentamethylcyclopentadienyl, indenyl, and heptamethylindenyl) in the absence and presence of a lewis base
✍ Scribed by Kazuo Soga; Yoshifumi Suzuki; Toshiya Uozumi; Eiichi Kaji
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 544 KB
- Volume
- 35
- Category
- Article
- ISSN
- 0887-624X
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✦ Synopsis
Several kinds of MgC12-supported half titanocene (XTiCl~; X = cyclopentadienyl, pentamethylcyclopentadienyl, indenyl, and heptamethylindenyl) catalysts were prepared and applied to propene polymerization using Al(i-Bu)~as cocatalyst. It was confirmed from the catalyst analysis that the ligand (X) is attached to titanium even after the reaction with Al(i-Bu)t. When polymerization was conducted without any external donor, those catalysts predominantly gave atactic PP. However, addition of a suitable monofunctional Lewis base like ethylbenzoate caused to change the stereospecificity of polymer from aspecific into highly isospecific. On the other hand, the use of a bifunctional donor like di-n-butylphthalate killed the activity almost completely. The isotactic PP was found to have a microstructure similar to that obtained with metallocene catalysts. (C 1997John Wiley & Sons, Inc. Keywords: combination of Ziegler-Natta and metallocene catalysts . half metallocene catalysts supported on magnesium dichloride . activation by ordinary alkylaluminums q improvement of catalyst isospecificity by electron donors . microstructure of isotactic polypropene * To whom all correspondenceshould be addressed.
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