Abstract: A highly active and stereoselective olefin polymerization catalyst component is obtained by halogenating a magnesium compound of the formula MgR.sub.1 R.sub.2 wherein R.sub.1 is an alkoxide or aryloxide group and R.sub.2 is an alkoxide or aryloxide group or halogen, with a halide of tetravalent titanium in the presence of a halohydrocarbon and an electron donor, and contacting the halogenated product with a tetravalent titanium halide.

Abstract: An olefin polymerization catalyst composition comprising: (a) a reaction product of an organoaluminum compound and an electron donor, and (b) a solid component which has been obtained by halogenating a magnesium compound with the formula MgR.sub.1 R.sub.2 wherein R.sub.1 is an alkyl, aryl, alkoxide or aryloxide group and R.sub.2 is an alkyl, aryl, alkoxide or aryloxide group or halogen, with a halide of tetravalent titanium in the presence of a halohydrocarbon, and contacting the halogenated product with a tetravalent titanium compound.

Abstract: An olefin polymerization process comprises contacting the monomer to be polymerized with a catalyst composition comprising: an organoaluminum compound, a first electron donor, and a product obtained by contacting a solid component comprising a magnesium halide in which the atomic ratio of chlorine to magnesium is at least 1.2, a titanium halide and a second electron donor, with a halohydrocarbon and thereafter with a tetravalent titanium compound.

Abstract: An olefin polymerization catalyst composition comprising:(a) a reaction product of an organo aluminium compound and an electron donor, and(b) a product obtained by contacting a solid component comprising a magnesium halide in which the atomic ratio of chlorine to magnesium is at least 1.2, a titanium halide and an electron donor, with a halohydrocarbon and with a tetravalent titanium compound.

Abstract: A titanium trichloride-catalyzed process for stereospecific polymerization of alpha-olefins, particularly propylene, to produce polymers of relatively high bulk density comprises employing as the TiCl.sub.3 catalyst component, used with an aluminum alkyl cocatalyst, a 0.1 to 30 millimicron fraction of a TiCl.sub.3 composition produced by(a) reacting TiCl.sub.4 with a complexing agent in a molar ratio of from 1:0.3 to 1:2;(b) reacting an organo-aluminum compound with a complexing agent in a molar ratio of at most 1:0.25;(c) reducing the complexed TiCl.sub.4 with the complexed organo-aluminum compound over a period of less than one hour at a temperature within the range 60.degree. to 110.degree. C. to produce TiCl.sub.3 particles having an average particle size of from 50 to 500 .mu.m;(d) subjecting the TiCl.sub.3 particles to a treatment to reduce the average particle size thereof to less than 50 .mu.m, and(e) classifying the TiCl.sub.

Abstract: A process for the preparation of violet TiCl.sub.3 by reducing TiCl.sub.4 with an organo-aluminum compound, characterized in that:(a) the TiCl.sub.4 is premixed with a complexing agent in an inert organic solvent, the molar ratio complexing agent:TiCl.sub.4 being within the range from 0.3:1 to 2:1;(b) the organo-aluminum compound is premixed with a complexing agent in an inert organic solvent, the molar ratio complexing agent:organo-aluminum compound being at least 0.25:1;(c) the reduction to TiCl.sub.3 and precipitation of TiCl.sub.3 are carried out by combining at least one stoichiometric equivalent of TiCl.sub.4 in the premixed composition of step (a) with one stoichiometric equivalent of the organoaluminum compound in the premixed composition of step (b) over a period of less than one hour at a temperature within the range 60.degree. to 110.degree. C.; and(d) the final concentration of violet TiCl.sub.3 in the reaction mixture is at least 0.2 mol./liter.

Abstract: A process for the preparation of an active TiCl.sub.3 catalyst which comprises:(a) reacting TiCl.sub.4 with a complexing agent in a molar ratio of from 1:0.3 to 1:2;(b) reacting an organo-aluminum compound with a complexing agent in a molar ratio of at most 1:0.25;(c) reducing the complexed TiCl.sub.4 with the complexed organo-aluminum compound over a period of less than one hour at a temperature within the range 60.degree. to 110.degree. C. to produce TiCl.sub.3 particles having an average particle size of from 50 to 500 .mu.m;(d) subjecting the TiCl.sub.3 particles to a treatment to reduce the average particle size thereof to less than 50 .mu.m, and(e) classifying the TiCl.sub.3 particles to separate a fraction having an average particle size of from 0.1 to 30 .mu.m.