Catalytic solid usable for the stereospecific polymerization of alpha-olefins, process for preparing it and process for polymerizing alpha-olefins in its presence

Abstract

Catalytic solids based on titanium trichloride complex, usable for the stereospecific polymerization of alpha-olefins, obtained by heat treatment, in the presence of a halogenated activating agent, of the liquid material resulting from bringing TiCl.sub.4, pretreated with an electron-donor compound, into contact with a composition (C) corresponding to the general formula AlR.sub.p (Y) .sub.q X .sub.3-(p+q) in which R represents a hydrocarbon radical or a hydrogen atom; Y represents a group chosen from --OR', --SR' and --NR'R", in which R' and R" each represent a hydrocarbon radical or a hydrogen atom; X represents a halogen; p is an arbitrary number such that 0<p<3; and q is an arbitrary number such that 0<q<3; the sum (p+q) being such that 0<(p+q).ltoreq.3. These catalytic solids of controllable porosity permit the production of a wide range of propylene polymers, in particular the propylene and ethylene copolymers known as "block" copolymers.

Dependencies are inferred from the claim text.