INVESTIGADORES
FERREIRA Maria Lujan
artículos
Título:
A Proposed Mechanism for Olefin Polymerization, 2. EHMO and MM2 Study
Autor/es:
FERREIRA, MARÍA LUJÁN
Revista:
MACROMOLECULAR THEORY AND SIMULATIONS
Editorial:
WILEY-V C H VERLAG GMBH
Referencias:
Año: 2002 vol. 11 p. 267 - 286
ISSN:
1022-1344
Resumen:
This paper reports the results about the modelpresented in Part 1 for olefin polymerization with metallocenes,using semiempirical extended Hückel molecularorbital (EHMO) and MM2 methods. The main aspects ofthe model are analyzed. These are bipyramidal or octahedralcoordination, two different olefins coordination andthe possibility of different active sites. A model of polymerizationfor a C2 catalyst, prototypical and with sterichindrance, and for a Cs catalyst was analyzed with MM2to evaluate steric effects. The electronic effects were modeledusing MAO to determine the feasibility of the model.Models for ethylene and propylene coordination andinsertion were considered. The insertion models wereonly of qualitative value and they were designed to evaluatethe effect of a triggering second olefin. A third olefincoordination (polymerizable or not) was considered for C2and Cs catalysts. Experimental evidence was analyzedwith the different aspects of the model.
