Reactivation of organochromium olefin polymerization catalyst in presence of oxygen
AssigneePhillips Petroleum Company
InventorJoseph A. Delap
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Abstract
A particulate catalyst support containing titanium is heated to calcination temperature and thereafter impregnated with a .pi. bonded organochromium compound. Thereafter the chromium-containing support is reactivated, at least a portion of the reactivation occurring in the presence of oxygen. In one embodiment at least 2 percent solvent is present as the catalyst is reactivated at approximately room temperature. In an alternate embodiment the support is calcined at a temperature within the range of 1450.degree. to 1650.degree.F. Such catalysts are particularly suitable for the production of high melt index polymer from at least one mono-1-olefin containing 2 to 8 carbon atoms per molecule.
Claims31
A process for producing a catalyst comprising:
- calcining a silica-containing particulate support containing titanium in air at a temperature within the range of 700.degree. to 2000.degree.F;
- thereafter impregnating the thus calcined titanium-containing support with a nonaqueous solution of a diarene organochromium compound having the following structure ##SPC2##
- wherein R is selected from the group consisting of hydrogen and alkyl radicals having from 1 to 6 carbon atoms;
- and
- thereafter treating the thus organochromium-impregnated support in the form of a free flowing powder containing at least 2 weight percent solvent, based on the weight of said impregnated support, with molecular oxygen at a temperature within the range of 40.degree. to 150.degree.F.
A process for producing a catalyst comprising:
- calcining in air a silica-containing particulate support containing titanium at a temperature within the range of 1450 to 1650.degree.F;
- thereafter impregnating the thus calcined titanium-containing support with a nonaqueous solution of a .pi. bonded organochromium compound;
- and
- thereafter treating the thus organochromium-impregnated support with molecular oxygen at a temperature within the range of 40.degree.-150.degree.F.
Dependencies are inferred from the claim text.