Preparation of an active TiCl3 catalyst

Claim 1

In the preparation of an active TiCl 3 olefin polymerization catalyst component by reducing TiCl 4 with an organo-aluminum compound which comprises: (a) premixing TiCl 4 with a complexing agent in an inert organic solvent, the molar ratio complexing agent: TiCl 4 being within the range from 0.3:1 to 2:1; (b) premixing the organo-aluminum compound with a complexing agent in an inert organic solvent, the molar ratio complexing agent: organo-aluminum compound being at least 0.25:1; (c) carrying out the reduction to TiCl 3 and precipitation of TiCl 3 in a single step by combining at least one stoichiometric equivalent of TiCl 4 in the premixed composition of step (a) with one stoichiometric equivalent of the organo-aluminum compound in the premixed composition of step (b) over a period of less than one hour at a temperature within the range 60° to 110° C., resulting in a reaction mixture having a concentration of at least 0.2 moles/liter of TiCl 3 particles having an average particle size of 50-500 millimicrons, the improvement which comprises subjecting said TiCl 3 particles to size reduction treatment to reduce the average particle size to less than 50 millimicrons and classifying the resulting TiCl 3 particles to recover a fraction having an average particle size of about 0.1-30 millimicrons.