Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

Methods for making a supported chromium catalyst are disclosed, and can comprise contacting a silica-coated alumina containing at least 30 wt. % silica with a chromium-containing compound in a liquid, drying, and calcining in an oxidizing atmosphere at a peak temperature of at least 650° C. to form the supported chromium catalyst. The supported chromium catalyst can contain from 0.01 to 20 wt. % chromium, and typically can have a pore volume from 0.5 to 2 mL/g and a BET surface area from 275 to 550 m.sup.2/g. The supported chromium catalyst subsequently can be used to polymerize olefins to produce, for example, ethylene-based homopolymers and copolymers having high molecular weights and broad molecular weight distributions.

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.

A method for preparing a homogenous catalyst for the production of linear alpha olefins includes: preparing a first pre-catalyst solution comprising a modifier and an organoaluminum compound in a first solvent wherein the first pre-catalyst solution is reacted and stored in a first vessel for a period of time of 1 hour to 90 days; preparing a second pre-catalyst solution comprising a second solvent, a ligand, and a chromium containing compound, wherein the second pre-catalyst solution is stored in a second vessel for a period of time of 1 hour to 90 days; and after a period of time, adding the first pre-catalyst solution to a catalyst pre-formation unit; after the same period of time, adding the second pre-catalyst solution to the catalyst pre-formation unit; forming a homogenous catalyst by mixing the first pre-catalyst solution and the second pre-catalyst solution; adding the homogeneous catalyst to a reaction vessel, wherein the reaction vessel comprises an alpha olefin; and forming the linear alpha olefin by mixing the homogeneous catalyst and the homogenous catalyst.

A method for preparing a homogenous catalyst for the production of linear alpha olefins includes: preparing a first pre-catalyst solution comprising a modifier and an organoaluminum compound in a first solvent wherein the first pre-catalyst solution is reacted and stored in a first vessel for a period of time of 1 hour to 90 days; preparing a second pre-catalyst solution comprising a second solvent, a ligand, and a chromium containing compound, wherein the second pre-catalyst solution is stored in a second vessel for a period of time of 1 hour to 90 days; and after a period of time, adding the first pre-catalyst solution to a catalyst pre-formation unit; after the same period of time, adding the second pre-catalyst solution to the catalyst pre-formation unit; forming a homogenous catalyst by mixing the first pre-catalyst solution and the second pre-catalyst solution; adding the homogeneous catalyst to a reaction vessel, wherein the reaction vessel comprises an alpha olefin; and forming the linear alpha olefin by mixing the homogeneous catalyst and the homogenous catalyst.

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 titanium compound, a solvent, and an amino acid. Also disclosed are olefin polymerization catalysts and pre-catalyst compositions thereof and methods of preparing olefin polymerization catalysts and pre-catalyst compositions thereof.

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 titanium compound, a solvent, and an amino acid. Also disclosed are olefin polymerization catalysts and pre-catalyst compositions thereof and methods of preparing olefin polymerization catalysts and pre-catalyst compositions thereof.

Provided herein are complexes for polymerization of linear alkynes to cyclic poly(alkynes), and methods of making and using same. For example, provided herein are compounds of formula (I) or formula (IV):

##STR00001##

Provided herein are complexes for polymerization of linear alkynes to cyclic poly(alkynes), and methods of making and using same. For example, provided herein are compounds of formula (I) or formula (IV):

##STR00001##