Methylaluminoxane: NMR analysis, cryoscopic measurements and cocatalytic ability in ethylene polymerization
✍ Scribed by Incoronata Tritto; Christel Méalares; Maria Carmela Sacchi; Paolo Locatelli
- Book ID
- 102942961
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 757 KB
- Volume
- 198
- Category
- Article
- ISSN
- 1022-1352
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✦ Synopsis
Abstract
Methylaluminoxane (MAO) solutions containing known amounts of AlMe~3~ and solutions of different MAO samples were characterized by several methods: (a) low temperature ^13^C NMR analysis; (b) determination of the molecular weight of the MAO samples by cryoscopy in benzene; (c) titration of AlMe~3~ using ^31^P NMR analysis of the AlMe~3~ · PPh~3~ complex (PPh~3~ = triphenylphosphine) formed after addition of defined amounts of PPh~3~ to the MAO solutions. The results confirm the disproportionation reaction caused by AlMe~3~ addition. The MAO molecular weights are shown to decrease after the AlMe~3~ addition according to a linear relationship.
The cocatalytic ability of these characterized MAOs was tested in ethylene polymerization catalyzed by rac‐Et(ind)~2~ZrCl~2~ (ind = indenyl) and the influence of the AlMe~3~ content, the “type” and the “aging” of MAO is correlated to the cocatalytic performance.