Density functional theory investigation of the alkylating strength of organoaluminum co-catalysts for ziegler-natta polymerization

Benoît Champagne, Valérie Cavillot, Jean Marie André, Philippe François, Ardéchir Momtaz

Résultats de recherche: Contribution à un journal/une revueArticleRevue par des pairs

Résumé

The ability of the Et2Al-R co-catalyst series [with R = Et, Cl, O-Me, O-iPr, NH-Me, S-Me, and S-iPr] to alkylate titanum chloride has been evaluated at the B3LYP/6-31G* level of approximation. The impact of dimerization and complexation by Lewis bases on their alkylating strength has been tackled. It turns out that both the dimerization and the complexation reactions increase the exothermicity of the global alkylation process. Nevertheless, these reactions can also annihilate the alkylating strength of these co-catalysts due to the formation of highly stable species. In particular, we have found that (i) the alkylating strength of Et2Al-R co-catalysts with R = O-R' and NH-R' is weak due to the formation of very stable dimers; (ii) the alkylating strength of Et2Al-S-R' increases upon adding Lewis bases, whereas Lewis bases make Et3Al less alkylating; and (iii) Et2Al-Cl is less affected by the presence of Lewis bases.

langue originaleAnglais
Pages (de - à)588-598
Nombre de pages11
journalInternational Journal of Quantum Chemistry
Volume106
Numéro de publication3
Les DOIs
Etat de la publicationPublié - 5 mars 2006

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