In British patent No. 1,140,649 of the 17th Oct. 1967 there is described a process for the polymerization and copolymerization of olefins, in which the operation is carried out in the presence of a catalyst obtained by activating by means of an organo-metallic compound the product of the reaction between a halogenated derivative of a transition metal and a solid support consisting of an oxygenated compound of a divalent metal free from hydroxyl groups.
During the reaction of the halogenated derivative and the solid support, complexes are formed containing halogen, divalent metal and transition metal. It is observed that a superficial halogenation of the solid support takes place. However, this halogenation is generally weak; the total quantity of halogen present is often less than 0.05 atoms of halogen per atom of divalent metal.