POLYMERIZATION OF ETHYLENE WITH THE (C5H5)(2)TICL2-(C2H5)(2)ALCL CATALYTIC-SYSTEM UNDER THE CONDITIONS OF CLASSICAL METALLOCENE CATALYSIS

The effects of the concentration of the components of the (C5H5)(2)TiC l2-(C2H5)(2)AlCl catalytic system, Al : Ti molar ratio, the solvent na ture, as well as temperature on the rate of ethylene polymerization an d the yield and molecular mass of the resulting polymer were studied. When polymerization was carried out in ethyl chloride at low concentra tions of the catalyst, the activity and specific productivity of the ( C5H5)(2)TiCl2-(C2H5)(2)AlCl catalytic system increased sharply. At [(C 5H5)(2)TiCl2] > 10(-6) mol/l and the Al : Ti molar ratios 1000-2000, t he specific productivity of the given catalytic system approached the productivity of the classical metallocene catalysts. It was establishe d that the enhanced activity of this system in ethyl chloride at 20-40 degrees C is associated with an increase in the rate constant of chai n propagation from 3-10 (toluene) to 360-550 l/(mol s) (ethyl chloride ). It was inferred that the high activity of the metallocene catalyst under investigation, which exceeds 30 PE macromoles/mol (C5H5)(2)TiCl2 , is related to a chain transfer to (C5H5)(2)AlCl. It was found that, in the temperature range 20-40 degrees C, the rate constant of this re action varies from 0.7 to 6.0 mol/(1 s).