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Kinetic investigation of ethylene polymerization catalyzed by nickel-diimine catalysts

✍ Scribed by Leonardo C Simon; Christopher P Williams; João B.P Soares; Roberto F de Souza

Publisher
Elsevier Science
Year
2001
Tongue
English
Weight
212 KB
Volume
165
Category
Article
ISSN
1381-1169

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✦ Synopsis

The effect of ethylene pressure on the activity of ethylene polymerization with the complex (1,4-bis(2,6-diisopropylphenyl))acenaphtenediimine-dichloronickel(II) (1) and trimethylaluminum was evaluated. At low ethylene concentrations, the polymerization rate is first order with respect to monomer concentration. At higher ethylene concentrations, the polymerization rate has a negative order with respect to monomer concentration. We propose a mechanism where the active sites are in a dynamic equilibrium with latent states, the later having two monomer molecules coordinated to the metal center. In situ spectroscopic observations corroborate the proposed mechanism and show that the cocatalyst nature might affect the ion pair formation.

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