Catalyst on a support for the polymerization of α-alkenes, particularly ethene

Claim 1

In processes for polymerizing an α-alkene containing from 2 to 8 carbon atoms, together with a minor quantity of at most 10 mole % of one or more other α-alkene co-monomers containing from 2 to 8 carbon atoms, the improvement consisting essentially in using a catalyst obtained by reacting a chromium-1,3-diketo compound of the formula Cr (OCR.sub.1 CR.sub.2 CR.sub.3 O).sub.3 in which R 1 , R 2 , R 3 each independently represent an alkyl group containing from 1 to 10 carbon atoms, and R 2 may also represent a hydrogen atom, with an organometallic compound of a metal from Group II or III of the Periodic Table in a hydrocarbon or halogenated hydrocarbon solvent, wherein hydrocarbyl groups containing from 1 to 20 carbon atoms are bound to the metal atom via a carbon atom, subsequently contacting the resulting hydrocarbon or halogenated hydrocarbon soluble reaction product with an inert inorganic support material, composed of silica having a pore volume of at least 1.5 cm 3 /g and a sodium content of at most 200 ppm, next heating the reaction product of the chromium compound deposited on the said silica support at a temperature of between about 200° and 1200° C. in a non-reducing atmosphere, and thereafter combining the resulting product with an organometallic compound of an element from Group II or III of the Periodic Table.