Highly selective nickel catalysts for ethylene oligomerization based on tridentate pyrazolyl ligands
✍ Scribed by Lucilene L. de Oliveira; Roberta R. Campedelli; Maria C.A. Kuhn; Jean-François Carpentier; Osvaldo L. Casagrande Jr.
- Publisher
- Elsevier Science
- Year
- 2008
- Tongue
- English
- Weight
- 362 KB
- Volume
- 288
- Category
- Article
- ISSN
- 1381-1169
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✦ Synopsis
A series of new nickel complexes NiCl 2 (L) based on tridentate NZN ligands (1, L = bis[2-(3,5dimethyl-pyrazolyl)
has been prepared and characterized by elemental analysis. Upon activation with methylaluminoxane (MAO) or diethylaluminum chloride (DEAC), these new pre-catalysts show high activity in ethylene oligomerization (TOF = 1.7-104.5 × 10 3 mol(ethylene) (mol(Ni)) -1 h -1 ), giving predominantly 1-butene (70-94% yield). The catalytic performance is substantially affected by the co-catalyst type and ligand environment, especially the bridge donor atom. Under optimized conditions ([Ni] = 10 mol, 30 • C, 20 bar ethylene, MAO-to-Ni = 250), pre-catalyst 3 leads to TOF = 104.5 × 10 3 h -1 and 70% selectivity for 1-butene.