Abstract: A catalyst for olefin polymerization comprising (A) a solid catalyst component which is prepared by causing (a) a magnesium compound, (b) a tetravalent titanium halide compound, and (c) an electron donor compound to come in contact with each other, (B) an organoaluminum compound of the formula R1pAlQ3-p, and (C) an organosilicon compound of the formula SiR2R3(OR4)(OR5), and (D) an organosilicon compound of the formula R6xSi(OR7)4-x exhibits a higher hydrogen activity than conventional catalysts.

Abstract: A catalyst for olefin polymerization comprising (A) a solid catalyst component which is prepared by causing (a) a magnesium compound, (b) a tetravalent titanium halide compound, and (c) an electron donor compound to come in contact with each other, (B) an organoaluminum compound of the formula R1pAlQ3-p, and (C) an organosilicon compound of the formula SiR2R3(OR4)(OR5), and (D) an organosilicon compound of the formula R6xSi(OR7)4-x exhibits a higher hydrogen activity than conventional catalysts.

Abstract: A solid catalyst component for olefin polymerization characterized by being formed from (a) a magnesium compound, (b) titanium tetrachloride, (c) a phthalic diester and a derivative thereof, and either (d1) a hydroxylated hydrocarbon compound (phenol, etc.) represented by a specific formula or (d2) a mercapto-containing hydrocarbon compound (thiophenol, etc.) represented by a specific formula. With a catalyst obtained from this solid catalyst component, an olefin polymer can be obtained in extremely high yield. In particular, a propylene polymer which retains high stereoregularity can be obtained in extremely high yield.

Abstract: Solid catalyst components and catalysts which contain (a) magnesium compound, (b) titanium tetrachloride, and (c) a phthalic acid diester or its derivative are useful in the synthesis of olefin polymers in high yields. Particularly, propylene polymers can be obtain in very high yields while retaining high stereoregularity.

Abstract: A solid catalyst component for olefin polymerization characterized by being formed from (a) a magnesium compound, (b) titanium tetrachloride, (c) a phthalic diester and a derivative thereof, and either (d1) a hydroxylated hydrocarbon compound (phenol, etc.) represented by a specific formula or (d2) a mercapto-containing hydrocarbon compound (thiophenol, etc.) represented by a specific formula. With a catalyst obtained from this solid catalyst component, an olefin polymer can be obtained in extremely high yield.

Abstract: A phthalic acid diester derivative represented by a specific formula and an electron donor used in an olefin polymerization catalyst containing the phthalic acid diester derivative as an effective component. The electron donor can produce polymers with a high stereoregularity at an extremely high polymerization activity and high yield, and exhibit a high response to hydrogen.

Abstract: Solid catalyst components and catalysts which comprise (a) a magnesium compound, (b) titanium tetra chloride, and (c) a phthalic acid diester or its derivative represented by a particular formula, can afford polymers of olefins in very high yield. Particularly, propylene polymers can be obtained in very high yield while retaining high stereoregularity. Moreover, they have high responsiveness to hydrogen.

Abstract: A phthalic acid diester derivative represented by a specific formula and an electron donor used in an olefin polymerization catalyst containing the phthalic acid diester derivative as an effective component. The electron donor can produce polymers with a high stereoregularity at an extremely high polymerization activity and high yield, and exhibit a high response to hydrogen.

Abstract: The present invention provides a solid catalyst component (A) obtained by allowing a dialkoxymagnesium or diaryloxymagnesium, a titanium compound, a diester of phthalic acid and a cyclic or chain polysiloxane to come in contact with one another.Further, the present invention provides a catalyst for polymerization of olefins prepared from the foregoing solid catalyst component (A), an organic aluminum compound and an organic silicon compound.