Ethylene Polymerization on Titanium Phenoxyimine Complexes with Different Structures
Kinetics and Catalysis
, E-ISSN: 1608-3210
Vorozhtzov Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Science
St. Petersburg Department of G.K. Boreskov Institute of Catalysis SB RAS
The kinetics of ethylene polymerization in the presence of catalytic systems based on methylaluminoxane-activated titanium bis(phenoxyimine) complexes with different structures has been investigated in the temperature range 30–70°C. The structures of the complexes have different substituents at the imine nitrogen atom and in the phenoxy group in the ligand, which affect the activity of the system and the molecular weight of polyethylene resulting from polymerization over at least 1 h. The polymerization kinetics is most sensitive to the structure of the substituent at the imine nitrogen atom and to bulky substituents in the ortho position of the phenoxy group. The results obtained are explained. An attempt is made to classify the influence of the substituents in the ligands. Process conditions ensuring living polymerization have been found. The physicochemical properties and structural features of the polyethylenes obtained have been determined.