Reduction of TiCl4 with reducing agents modified with Lewis bases

Claim 1

In a process for preparing a TiCl 3 catalyst complex for stereoregular polymerization of alpha-olefins, wherein said catalyst complex is prepared by reducing TiCl 4 in a non-reactive solvent with an aluminum alkyl to obtain a brown reduced TiCl 3 solid compound and activating the brown reduced TiCl 3 solid compound by conversion to the purple form, the improvements comprising: (1) in said reduction step (a) contacting TiCl 4 with a dihydrocarbon ether/aluminum alkyl complex at a temperature within the range of about -80° to about +50° C., wherein said aluminum alkyl compound is selected from aluminum triethyl, diethyl aluminum chloride and mixtures of diethyl aluminum chloride and ethyl aluminum dichloride, and said complex being obtained by complexing said aluminum alkyl with an excess of said ether, wherein the mole ratio of ether:aluminum alkyl:TiCl 4 is in the range of about 1.01-10:1-5:1-20 and the ratio of dihydrocarbon ether to aluminum alkyl is in the range of about 1.01 to 5:1; (b) warming the resulting reaction mixture of (a) to about 25°-90° C. and maintaining said temperature for about 1/2 to about 6 hours; and (a) in said activating step, contacting said brown reduced solid TiCl 3 complex with one of TiCl 4 or a chlorinated hydrocarbon for a time and temperature sufficient to convert the brown TiCl 3 , to the purple form.