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Ethylene polymerization with homogeneous Ziegler‐Natta catalysts: theoretical study on the role of ion pairs in the polymerization mechanism
Author(s) -
Fusco Roberto,
Longo Luca,
Masi Francesco,
Garbassi Fabio
Publication year - 1997
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.1997.030180511
Subject(s) - polymerization , olefin fiber , natta , metallocene , catalysis , ethylene , polymer chemistry , chemistry , olefin polymerization , homogeneous , bimetallic strip , organic chemistry , polymer , thermodynamics , physics
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 2 − , the bimetallic complex Cp 2 TiCH 3 (C 2 H 4 ) δ+ · Al(CH 3 ) 2 Cl 2 δ−and the olefin‐separated ion pair Cp 2 TiCH 3 + /C 2 H 4 /Al(CH 3 ) 2 Cl 2 − , shows that the most feasible polymerization mechanism occurs via olefin‐separated ion pair.