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Zirconium complexes as catalysts for the oligomerisation of ethylene: the role of chelate ligands and the Lewis acid cocatalyst in the generation of the active species

Citation

Jones, DJ and Cavell, KJ and Keim, W, Zirconium complexes as catalysts for the oligomerisation of ethylene: the role of chelate ligands and the Lewis acid cocatalyst in the generation of the active species, Journal of Molecular Catalysis A: Chemical, 138, (1) pp. 37-52. ISSN 1381-1169 (1999) [Refereed Article]

DOI: doi:10.1016/S1381-1169(98)00144-7

Abstract

Highly effective catalysts for the conversion of ethylene into linear α-olefins may be generated in situ from zirconium tetrachloride, a β- aminoketone or β-aminothioketone ligand and an alkylaluminium chloride Lewis acid cocatalyst. Catalysts may also be generated from ZrCl4 · 2HL adducts (where HL = monodentate, oxygen-bound β-aminoketones), and from bis-ligand complexes of the type ZrCl2L2 (where L = monovalent, bidentate β- aminoketones or β-aminothioketones) on treatment with an alkylaluminium chloride cocatalyst. Product distribution and catalyst activity can be adjusted by ligand substituent variation and/or by the method of catalyst formation. Catalyst systems generated from preformed complexes, ZrCl2L2, were in general significantly more active than those formed in situ or from the bis-ligand adducts, ZrCl4 · 2HL. Activities of up to 60,000 turnovers/h were obtained with selected complexes. However, in situ mixtures and bis- ligand adducts generally gave a much narrower oligomer distribution, with up to 95% of the oligomers occurring in the C4-C10 range for a number of the systems tested. In situ NMR (nuclear magnetic resonance) tests indicate that complex ligand/cocatalyst interactions are present and that these new oligomerisation systems are active even under very mild conditions, 30°C and 1 atm ethylene.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Other Chemical Sciences
Research Field:Organometallic Chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Chemical Sciences
Author:Jones, DJ (Dr Jones)
Author:Cavell, KJ (Professor Kingsley Cavell)
ID Code:16465
Year Published:1999
Web of Science® Times Cited:23
Deposited By:Chemistry
Deposited On:1999-08-01
Last Modified:2011-08-04
Downloads:0

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