Dependence of the activity of titanium-aluminium complexes during polymerization of ethylene on the nature of the aryloxy radicals bound to the titanium atom

Abstract

The authors have studied the catalytic activity of organic titanium-aluminium complexes obtained by the interaction of Ti(OAr) 2Cl or Ti(OAr) 4 with Al(C 2H 5) 2 where Ar = C 6H 4X (X=H, Me- p, Me- m, OMe- p, OMe- m, Cl- p, Cl- m and Br- p) on low pressure polymerization of ethylene. The activity of the complexes studied rised with increase in the acceptor properties of the aryloxy groups. A quantitative relation was found between change in the positive charge on the titanium atom and the rate of the elementary reactions of polymerization of ethylene. The relation between the growth rate of the polymer chain and the constants σ of the substituents in the aromatic cycle is described by the Hammett equation. The influence of the nature of the aryloxy radicals on the properties of PE is shown.