PURPOSE: To provide the titled catalyst capable of giving highly stereoregular polyolefin without any deashing operation, comprising a piperizine derivative, organoaluminum compound and a specific solid component prepared from magnesium compound, aluminum compound, titanium compound, liquid hydrocarbon and electron donor.
CONSTITUTION: The objective polymerization catalyst can be obtained by formulation of (A) a solid catalytic component (B) a piperizine derivative of formula (R 1 WR 4 are each H, alkyl, etc.) and (C) an organo-aluminum compound. The solid catalytic component A can be made as follows: MgCl 2 and Al 2 O 3 are ground together to prepare a substance. This substance, ≤2pts.wt. based on 1pt.wt. of said substance of a tetraalkoxytitanium, an aliphatic hydrocarbon liquid at -30W+50°C, and an aliphatic alcohol are mixed to form a homogeneous solution. This solution is then dripped on TiCl 4 kept at ≤0°C followed by addition of a phthalic diester at ≥80°C, then reaction at ≥100°C. The resulting solid is separated, being allowed to react with TiCl 4 .