Catalyst component and catalyst for the polymerization of alpha-olefins to stereoregular polymers having narrow molecular weight distribution

摘要

Disclosed is a component for a catalyst for the polymerization of alpha-olefins to stereoregular polymers having narrow molecular weight distribution. The product is formed by the reaction of a solid catalyst-forming component comprising (1) a Ti compound having at least one Ti-halogen bond and (2) optionally, an electron-donor compound, supported on an anhydrous Mg dihalide in active form, with certain amounts of an organic compound (AH) containing at least one active hydrogen atom, in the presence of a liquid medium which is inert with respect to the Ti compound and the other components of the catalyst component, and which has a dielectric constant greater than 2 at 20 DEG C. Catalysts comprising the reaction product of the solid catalyst component prepared as above described, with an Al-alkyl compound and an electron-donor compound are also disclosed.