Unusual Effect of Diethyl Zinc and Triisobutylaluminium in Ethylene/1-Hexene Copolymerisation using an MgCl2-Supported Ziegler-Natta Catalyst
✍ Scribed by Soazig G. M. Périn; John R. Severn; Cor E. Koning; John C. Chadwick
- Publisher
- John Wiley and Sons
- Year
- 2006
- Tongue
- English
- Weight
- 157 KB
- Volume
- 207
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
Summary: The use of tri__iso__butylaluminium and diethyl zinc as cocatalyst and chain transfer agent respectively in ethylene/1‐hexene copolymerisation, carried out with a Ziegler‐Natta catalyst of type MgCl~2~/TiCl~4~/di__iso__butyl phthalate, has been found to give significantly higher comonomer incorporation than was obtained when triethylaluminium was used in combination with diethyl zinc. Tri__iso__butylaluminium reacts readily with diethyl zinc, yielding metallic zinc, most likely via the formation of intermediate hydride species. In contrast, the use of 2,6‐dimethylpyridine as external donor in this system has been found to have relatively little effect on comonomer incorporation and distribution, indicating that a change from tendentially isospecific to syndiospecific propagation in propene polymerisation is not accompanied by a major improvement in comonomer distribution in ethylene/1‐hexene copolymerisation.
^1^H NMR spectrum of the liquid product of the reaction between tri__iso__butylaluminium and diethyl zinc.
image^1^H NMR spectrum of the liquid product of the reaction between tri__iso__butylaluminium and diethyl zinc.