A method comprising a) drying a support material comprising silica at temperature in the range of from about 150° C. to about 220° C. to form a dried support; b) contacting the dried support with methanol to form a slurried support; c) subsequent to b), cooling the slurried support to a temperature of less than about 60° C. to form a cooled slurried support; d) subsequent to c), contacting the cooled slurried support with a titanium alkoxide to form a titanated support; and e) thermally treating the titanated support by heating to a temperature of equal to or greater than about 150° C. for a time period of from about 5 hours to about 30 hours to remove the methanol and yield a dried titanated support.

Supported chromium catalysts with an average valence less than +6 and having a hydrocarbon-containing or halogenated hydrocarbon-containing ligand attached to at least one bonding site on the chromium are disclosed, as well as ethylene-based polymers with terminal alkane, aromatic, or halogenated hydrocarbon chain ends. Another ethylene polymer characterized by at least 2 wt. % of the polymer having a molecular weight greater than 1,000,000 g/mol and at least 1.5 wt. % of the polymer having a molecular weight less than 1000 g/mol is provided, as well as an ethylene homopolymer with at least 3.5 methyl short chain branches and less than 0.6 butyl short chain branches per 1000 total carbon atoms.

A method comprising a) drying a support material comprising silica at temperature in the range of from about 150° C. to about 220° C. to form a dried support; b) contacting the dried support with methanol to form a slurried support; c) subsequent to b), cooling the slurried support to a temperature of less than about 60° C. to form a cooled slurried support; d) subsequent to c), contacting the cooled slurried support with a titanium alkoxide to form a titanated support; and e) thermally treating the titanated support by heating to a temperature of equal to or greater than about 150° C. for a time period of from about 5 hours to about 30 hours to remove the methanol and yield a dried titanated support.

A method comprising a) drying a support material comprising silica at temperature in the range of from about 150° C. to about 220° C. to form a dried support; b) contacting the dried support with methanol to form a slurried support; c) subsequent to b), cooling the slurried support to a temperature of less than about 60° C. to form a cooled slurried support; d) subsequent to c), contacting the cooled slurried support with a titanium alkoxide to form a titanated support; and e) thermally treating the titanated support by heating to a temperature of equal to or greater than about 150° C. for a time period of from about 5 hours to about 30 hours to remove the methanol and yield a dried titanated support.

A method comprising contacting a silica support with a titanium-containing solution to form a titanated silica support, wherein the titanium-containing solution comprises a solvent; a ligand comprising a glycol, a carboxylate, a peroxide, or a combination thereof; and a titanium compound having the formula Ti(acac).sub.2(OR).sub.2, wherein “acac” is acetylacetonate and wherein each R independently is ethyl, isopropyl, n-propyl, isobutyl, or n-butyl.

A method comprising contacting a silica support with a titanium-containing solution to form a titanated silica support, wherein the titanium-containing solution comprises a solvent; a ligand comprising a glycol, a carboxylate, a peroxide, or a combination thereof; and a titanium compound having the formula Ti(acac).sub.2(OR).sub.2, wherein “acac” is acetylacetonate and wherein each R independently is ethyl, isopropyl, n-propyl, isobutyl, or n-butyl.

Catalyst preparation systems and methods for preparing reduced chromium catalysts are disclosed, and can comprise irradiating a supported chromium catalyst containing hexavalent chromium with a light beam having a wavelength within the UV-visible light spectrum. Such reduced chromium catalysts have improved catalytic activity compared to chromium catalysts reduced by other means. The use of the reduced chromium catalyst in polymerization reactor systems and olefin polymerization processes also is disclosed, resulting in polymers with a higher melt index.

Catalyst preparation systems and methods for preparing reduced chromium catalysts are disclosed, and can comprise irradiating a supported chromium catalyst containing hexavalent chromium with a light beam having a wavelength within the UV-visible light spectrum. Such reduced chromium catalysts have improved catalytic activity compared to chromium catalysts reduced by other means. The use of the reduced chromium catalyst in polymerization reactor systems and olefin polymerization processes also is disclosed, resulting in polymers with a higher melt index.

Supported chromium catalysts with an average valence less than +6 and having a hydrocarbon-containing or halogenated hydrocarbon-containing ligand attached to at least one bonding site on the chromium are disclosed, as well as ethylene-based polymers with terminal alkane, aromatic, or halogenated hydrocarbon chain ends. Another ethylene polymer characterized by at least 2 wt. % of the polymer having a molecular weight greater than 1,000,000 g/mol and at least 1.5 wt. % of the polymer having a molecular weight less than 1000 g/mol is provided, as well as an ethylene homopolymer with at least 3.5 methyl short chain branches and less than 0.6 butyl short chain branches per 1000 total carbon atoms.

A composition, such as a catalyst precursor or a catalyst comprising a Cr coated silica support with particularly defined levels of Na and Al, such that the resulting Cr/Silica catalyst has an increased MI potential is disclosed. In an embodiment, the disclosed catalyst composition comprises a silica-containing substrate made using a base-set gel and comprising a catalytically active metal consisting of Cr, with Al impurities of less than 50 ppm and Na in an amount of less than 800 ppm of the catalyst composition. The disclosed composition has an increased MI potential over a catalyst having higher Al content, a lower Na:Al ratio, or both. Methods of making the disclosed composition, and methods of using it to prepare a polyethylene are also disclosed.