BigPatents India

- Process for the preparation of a catalyst of Ziegler-Natta type comprising a granular support based on a refractory oxide, characterized in that the stages of the process include: (a) and (b) bringing the granular support, in the course of two separate stage (a) and (b), into contact with a dialkylmagnesium and then with an organoaluminium compound, or with an organoaluminium compound and then with a dialkylmagnesium, (c) bringing the product originating from stage (a) and (b) into contact with an organic halogen compound, and (d) bringing the solid originating from stage © into contact with at least one tetravalent titanium compound.