Chromium-based catalysts for the polymerization of 1-alkenes

Claim 1

A process for the polymerization of at least one 1-alkene containing from 2 to 8 carbon atoms, with from 0 to 10 mole% of at least one other 1-alkene containing from 2 to 8 carbon atoms, in the presence of a catalyst essentially composed of (1) a supported chromium compound and (2) an organometal compound of an element of Group II or III of the periodic system, wherein said catalyst has been prepared by (a) contacting in an inert solvent medium (1) a chromium complex of a 1,3-diketo compound of the formula ##STR2## wherein each of R 1 and R 3 represents an alkyl group of from 1 to 10 carbon atoms and R 2 represents hydrogen or an alkyl group of from 1 to 10 carbon atoms, with (2) an organometallic compound of a metal of Group II or III of the periodic system, in which said metal is bonded to at least one hydrocarbyl group containing from 1 to 20 carbon atoms through a carbon atom thereof; (b) subsequently depositing the reaction products of step (a) on an inert inorganic support; (c) heating the thus-deposited reaction product of step (b) on said support in a non-reducing atmosphere at a temperature between about 200° and 1200° C.; and (d) subsequently adding an activating amount of an organometallic compound of a metal of Group II or III of the periodic system to the product resulting from step (c).