Copolymerization of Ethylene with Alpha-Olefins over Supported Titanium-Magnesium Catalysts Containing Titanium Compounds in Different Oxidation and Coordination States

Data were obtained on the copolymerization of ethylene with alpha-olefins over supported titanium-magnesium catalysts (TMC) prepared on the same magnesium dichloride support but differing in the composition and oxidation state of titanium. The copolymerization kinetics of ethylene with 1-hexene over TMC of different compositions were studied. Data on the composition of the produced ethylene-1-hexene copolymers, their molecular weight distribution, thermophysical characteristics, and branching distribution were presented. The constants of ethylene-1-hexene copolymerization over catalysts with different compositions were calculated. The TMC containing only Ti(II) compounds as the active component exhibited increased copolymerizing ability compared to the conventional TiCl4/MgCl2 catalyst containing Ti(III) compounds as the active component. In addition, TMC with Ti(II) as an active component produces copolymers with a more uniform branching distribution. It was shown that the TMC containing isolated Ti(II) ions could be used to produce X-ray amorphous ethylene-propylene elastomers with a high yield.