Phosphated alumina or aluminum phosphate chromium catalyst
AssigneePhillips Petroleum Company
InventorMax P. McDaniel
Life of this patent
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Abstract
A catalyst system suitable for olefin polymerization comprising a catalyst component made up of chromium on a phosphated alumina or low phosphorus aluminum phosphate base and optionally an organometal cocatalyst. The resulting catalyst is particularly sensitive to the effects of hydrogen as a molecular weight control agent, thus allowing the production of polymers of having a melt flow varying over a wide spectrum utilizing the same catalyst.
Claims33
A method of making a catalyst system comprising
- (a) treating a separately prepared alumina gel with a phosphating agent to give a surface treatment and activating the thus treated gel in an oxidizing atmosphere at an elevated temperature, said gel either having a chromium compound coprecipitated therewith or having a chromium compound added thereto prior to said activating;
- and
- (b) combining an organometal cocatalyst with the thus activated catalyst.
A catalyst system comprising
- (a) a catalyst comprising a chromium oxide on a surface phosphated alumina gel base;
- and
- (b) an organometal cocatalyst.
A method of preparing a catalyst comprising treating a separately prepared low phosphorus aluminum phosphate gel with a phosphating agent to give a surface treatment and activating the thus treated gel in an oxidizing atmosphere at an elevated temperature, said gel either having a chromium compound coprecipitated therewith or having a chromium compound added thereto prior to said activating.
A method of making a catalyst comprising
- (a) treating an alumina hydrogel with orthophosphoric acid, adding a chromium compound to the resulting treated hydrogel, converting the hydrogel to a xerogel by azeotrope drying or washing with a water miscible organic liquid, and activating the thus treated xerogel in air for a time within the range of 1 minute to 48 hours at a temperature of 150.degree.-800.degree. C., wherein said phosphoric acid is used in an amount to give 0.01 to 0.5 milligrams phosphorus per square meter of surface area of said alumina zerogel and said chromium compound is added in an amount sufficient to provide chromium in an amount within the range of 0.1 to 5 weight percent based on the weight of said xerogel;
- and
- (b) combining an organometal cocatalyst with the thus activated catalyst.
A method of making a catalyst system comprising
- (a) treating an alumina xerogel with phosphoric acid in an amount sufficient to give 0.01 to 0.5 milligrams phosphorus per square meter of surface area of said alumina xerogel, adding a chromium compound in an amount sufficient to give chromium in an amount within the range of 0.1 to 5 weight percent based on the weight of said xerogel, activating said xerogel containing said chromium by heating in air for a time within the range of 1 minute to 48 hours at a temperature of 150.degree.-800.degree. C.;
- and
- (b) combining an organometal cocatalyst with the thus activated catalyst.
Dependencies are inferred from the claim text.