Polymerization catalyst

Claim 1

A process for preparing an improved catalyst suitable for the polymerization of an olefinic material which comprises forming a mixture of chromium oxide and at least one material selected from the group consisting of silica, alumina, zirconia, and thoria, at least part of the chromium being in the hexavalent state at the initial contacting of monomer therewith, an organometal component of the formula RxM wherein R is selected from the group consisting of hydrogen alkyl, aryl, cycloalkyl, alkoxy radicals and combinations of these radicals containing up tO 12 carbon atoms, at least one R group being a hydrocarbon radical, M is selected from the group consisting of aluminum, gallium, indium, thallium zinc, boron, lead, lithium, zirconium, cobalt, magnesium and tin, and x is an integer equal to the valence of M, and a vanadium component selected from the group consisting of vanadium chelates and vanadyl chelates of beta-diketones of the formula where each R'' is individually selected from the group consisting of alkyl, aryl, cycloalkyl radicals and combinations of said radicals, each R'' containing up to 12 carbon atoms, and then coactivating the admixture thus formed under coactivation conditions, including heating said admixture in an oxygen-containing gas at a coactivation temperature for a time sufficient to render the mass catalytic in character, said conditions including the following: a mol ratio of the vanadium compound to chromium of 0.1 to 10, a mol ratio of organometal compound to vanadium compound of 0.1 to 30, a mol ratio of vanadium compound to said selected material of 0.001 to 10 and passing said oxygen-containing gas through said admixture at a temperature in the approximate range of 500* F. to 1,500* F. until the dew point of the effluent gas from the coactivation has dropped below approximately 0* F.