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US 4,364,840 AGranted
Phosphated silica-chromium catalyst with boron-containing cocatalyst
AssigneePhillips Petroleum Company
InventorsMax P. McDaniel, Marvin M. Johnson
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 silica-containing base and a boron-containing 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.
Claims24
A method of making a catalyst system comprising:
- (a) treating a silica-containing support with a phosphating agent and activating said thus treated catalyst in an oxidizing atmosphere at an elevated temperature, said support either having a chromium compound coprecipitated therewith or having a chromium compound added thereto prior to said activating in said oxidizing atmosphere, said phosphating agent being utilized in an amount sufficient to give 0.1 to 20 mole percent of said phosphating agent based on the moles of silica in said silica-containing support;
- and
- (b) combining a cocatalyst selected from trihydrocarbyl boron compounds, boron alkoxides and halogenated alkyl boron compounds with said catalyst.
A catalyst system comprising
- (a) a catalyst comprising a chromium oxide on a phosphated silica-containing base wherein there is present 0.01 to 0.5 mg P/m.sup.2 of silica surface as measured by BET nitrogen sorption;
- and
- (b) a cocatalyst selected from trihydrocarbyl boron compounds, boron alkoxides and halogenated alkyl boron compounds.
Dependencies are inferred from the claim text.