Chain Propagation for Polyethylene and Polypropylene Polymerization with Late Metal Homogeneous Catalysts

Dean M. Philipp, Richard P. Muller, and William A. Goddard, III.

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Abstract: Quantum chemical calculations using the B3LYP density functional method as implemented by the Jaguar program were used to look at chain propagation for polyethylene and polypropylene polymerization by late metal homogeneous catalysts. Model catalysts were used to determine the effects of varying the metal, coordinating ligands, and monomer units (propylene versus ethylene). General trends of the ethylene complexation energy and the insertion energy barrier increasing as the metal was changed to one further down or further to the left in the periodic table were found (though the reverse was actually the case for the insertion barrier for the first transition series). The weaker the trans influence of the coordinating ligand, the larger the observed ethylene complexation energies and insertion energy barriers. Finally, it was found that using propylene instead of ethylene yielded slightly larger monomer complexation energies and insertion barriers, while two possible propagation pathways for polypropylene were energetically similar.



This research was supported The Dow Chemical Company.