Abstract: A process for the preparation of ethylene-propylene impact copolymers at improved catalyst productivity rates involving the formation of a propylene prepolymer by polymerization of propylene in liquid phase in the presence of a catalyst system containing titanium halide supported on magnesium halide and aluminum alkyl complexed with an electron donor. Ethylene and propylene are block polymerized onto the prepolymer in a vapor phase reaction zone in the presence of further added quantities of aluminum alkyl components.

Abstract: A process for the stereospecific polymerization of an alpha olefin with at least three carbon atoms, with a catalyst system comprising (a) a titanium halide, and (b,i) a reaction product of an organoaluminum halide and an aromatic compound or (b,ii) a reaction product of an organoaluminum halide, an aromatic compound and a halogen-free organoaluminum compound, the aromatic compound being a hydroxy aromatic compound which comprises a sec. or tert. alkyl group in both ortho-positions in respect of the hydroxyl group.

Abstract: A process for the preparation of an olefin polymerization catalyst component which comprises contacting a solid composition obtained by combining a magnesium halide, an electron donor and a tetravalent titanium compound, this composition being substantially free from aluminum compounds, with a liquid medium comprising a halide of B, Al, Ga, In, Tl, Sn or Sb, these elements being present in their highest valency state or a halide of tetravalent Te, and removing from the catalyst component substantially all metal halide originating from the liquid medium as by washing the catalyst component with a hydrocarbon or halohydrocarbon liquid.

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: A process for the preparation of an olefin polymerization catalyst component which comprises contacting a solid composition obtained by combining a magnesium halide, an electron donor and a tetravalent titanium compound, this composition being substantially free from aluminum compounds, with a liquid medium comprising a halide of B, Al, Ga, In, Tl, Sn or Sb, these elements being present in their highest valency state or a halide of tetravalent Te, and removing from the catalyst component substantially all metal halide originating from the liquid medium as by washing the catalyst component with a hydrocarbon or halohydrocarbon liquid.

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: Dimerization of alpha,beta-unsubstituted 1-alkenes, having at least three carbon atoms, in the presence of a catalyst comprising(a) a titanium-containing component of the formulaCp.sub.2 TiXY,wherein Cp represents an optionally alkyl-substituted cyclopentadienyl group, X represents a halogen atom or an alkyl group, and Y represents a halogen atom,(b) an alkylaluminum halide, and(c) a nitrogen Lewis base,is characterized by high reaction selectivity to certain dimer products and little formation of higher polymers.