Abstract: A process for producing an olefin polymer by polymerizing an olefin with a catalyst system comprising an organoaluminum compound and a supported catalyst component prepared by using as the carrier a solid product obtained by the reaction of an organomagnesium compound with an aluminum halide compound and/or a silicon halide compound, by heating a liquid ether complex of titanium trichloride in the presence of said carrier, and further reacting the resulting titanium trichloride-containing solid product with titanium tetrachloride. By this process, the olefin polymer having a broad molecular weight distribution suitable for flow molding or extrusion molding is produced.

Abstract: Solid catalyst components produced by reacting an organomagnesium compound with an alkoxy compound of the formula,R.sup.1.sub.a Al(OR.sup.2).sub.b X.sub.cwherein R.sup.1 and R.sup.2 are each a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen atom and a, b and c are numbers satisfying the equations at the same time,0.ltoreq.a<3, 0<b.ltoreq.3, 0.ltoreq.c<3, and a+b+c=3 and/or of the formula,R.sup.3.sub.d P(OR.sup.4).sub.e X.sub.fwherein R.sup.3 and R.sup.4 are each a hydrocarbon group having 1 to 20 carbon atoms, X is a halogen atom, and d, e and f are numbers satisfying the equations at the same time,0.ltoreq.d<3, 0<e.ltoreq.3, 0.ltoreq.f<3, and d+e+f=3to produce a solid product, and allowing the solid product to support a titanium compound and/or a vanadium compound, and a method for producing polyolefins which comprises polymerizing olefin in the presence of a catalyst system comprising said solid catalyst component and an organoaluminum compound.

Abstract: A catalyst system prepared by mixing components (A), (B) and (C):(A) a solid titanium component prepared from an organo-magnesium compound, a silicon halide compound and/or an aluminum halide compound, an electron donor and TiCl.sub.4,(B) an organoaluminum activator, and(C) an electron donor.

Abstract: .alpha.-Olefin polymers of high stereoregularity are prepared by polymerizing the .alpha.-olefin with a catalyst prepared by mixing components (A), (B) and (C):(A) a solid titanium component prepared from an organo-magnesium compound, a silicon halide compound and/or an aluminum halide compound, an electron donor and TiCl.sub.4,(B) an organoaluminum activator, and(C) an electron donor.

Abstract: A process for the polymerization of olefins in the presence of a catalyst comprising a titanium compound and/or vanadium compound supported on a solid carrier and an organoaluminum compound, characterized in that said solid carrier comprises a solid product obtained by the reaction of an organomagnesium compound or a reaction mixture resulting from the organomagnesium compound and at least one compound selected from the group consisting of magnesium hydroxide, calcium hydroxide, zinc hydroxide and aluminum hydroxide, with an aluminum halogenide and/or silicon halogenide, whereby there are produced olefine polymers in an extremely large amount per unit weight of catalyst.