Ethylene polymerization with homogeneous Ziegler-Natta catalysts: theoretical study on the role of ion pairs in the polymerization mechanism

✍ Scribed by Roberto Fusco; Luca Longo; Francesco Masi; Fabio Garbassi

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 420 KB
• Volume: 18
• Category: Article
• ISSN: 1022-1336
• DOI: 10.1002/marc.1997.030180511

✦ Synopsis

Abstract

The thermodynamics of the reaction of an ethylene molecule with the Cp~2~TiCH~3~Cl/Al(CH~3~)~2~Cl system (Cp = η~5~‐C~5~H~5~), as a model for olefin polymerization with homogeneous Ziegler‐Natta catalysts, was investigated via quantum mechanical DFT calculations. The comparison of the calculated energies for three possible titanium‐olefin coordinated intermediates, the ionic complex Cp~2~TiCH~3~(C~2~H~4~)^+^/Al(CH~3~)~2~Cl, the bimetallic complex Cp~2~TiCH~3~(C~2~H~4~)^δ+^ · Al(CH~3~)~2~Cl and the olefin‐separated ion pair Cp~2~TiCH/C~2~H~4~/Al(CH~3~)~2~Cl, shows that the most feasible polymerization mechanism occurs via olefin‐separated ion pair.