Abstract: The invention relates to a process for preparing supported catalysts for the copolymerization of ethylene with higher alpha-olefins, characterized in that a compound of a transition metal of Groups IV, V and VI of the Periodic Table of Elements, used at its maximum valency, is precipitated on to a support of magnesium chloride and possibly aluminum chloride by a reduction reaction in two stages, employing reducing agents selected for the first stage from among alkylaluminum dihalides, and for the second stage from among organo-metallic compounds with a higher reducing power than that of the alkylaluminum dihalides.These catalysts are particularly well suited to the copolymerization in the gas phase of ethylene and higher alpha-olefins.

Abstract: A vanadium dichloride-ether complex is carried on a porous support. This complex can be produced by either forming VCl.sub.2 and thereafter complexing the material with an ether or forming an ether complex with VCl.sub.4 or VCl.sub.3 and thereafter reducing the vanadium compound to VCl.sub.2. It is also possible to carry out the complexing reaction and the reduction essentially simultaneously. The resulting catalyst in combination with a cocatalyst is capable of giving high activity in olefin polymerization and demonstrates good sensitivity to molecular weight control agents, thus allowing the production of a broad spectrum of polymers so far as molecular weight is concerned.

Abstract: A catalyst and method in which the catalyst is used with an aluminum cocatalyst in the polymerization and copolymerization of 1-olefins and is prepared by reacting a monofunctional organic silicon compound with silica, alumina, or the like followed by reacting the product of this reaction with a Group IIA organometallic compound or complex, then reacting this product with a halide or alkoxide of a metal of Group IVB or Group VB or mixtures thereof. If desired, the halide or alkoxide may be first reacted with the silicon compound reaction product before the reacting with the organometallic compound or complex.

Abstract: Ethylene is homopolymerized or copolymerized with another olefin monomer in the presence of a catalyst system comprising organo metal cocatalyst and a titanium-containing catalyst component, such titanium-containing catalyst component being obtained by reacting together a porous particulate material, an organo magnesium compound, a halogen or interhalogen compound and titanium tetrachloride.