Modified chromium-based catalyst compositions for olefin polymerization are disclosed. The modifiers prevent or reduce catalyst particle aggregation providing improved catalyst particle dispersion and consistent flow index response of the compositions in olefin polymerization.

This invention provides a blow molding composition comprising a high molecular weight, chromium catalyzed ethylene copolymer (also referred to as a polyethylene resin) and a nucleating agent. The composition enables a more efficient blow molding process by reducing the number of malformed/rejected parts that are produced when the process is operated at high rates. In a preferred embodiment, the malformed parts may be reground and added to “virgin” composition for the production of prime parts.

This invention provides a blow molding composition comprising a high molecular weight, chromium catalyzed ethylene copolymer (also referred to as a polyethylene resin) and a nucleating agent. The composition enables a more efficient blow molding process by reducing the number of malformed/rejected parts that are produced when the process is operated at high rates. In a preferred embodiment, the malformed parts may be reground and added to “virgin” composition for the production of prime parts.

A tetraanionic OCO pincer ligand metal-oxo-alkylidene complex is prepared from a trianionic pincer ligand supported metal-alkylidyne. The metal can be tungsten or other group 5-7 transition metal. The tetraanionic pincer ligand metal-oxo-alkylidene complex, a trianionic OCO pincer ligand metal complex, or a trianionic ONO pincer ligand metal complex can be used to polymerize cycloalkenes. The poly(cycloalkene)s are predominantly cis-alkene macrocyclics.

A tetraanionic OCO pincer ligand metal-oxo-alkylidene complex is prepared from a trianionic pincer ligand supported metal-alkylidyne. The metal can be tungsten or other group 5-7 transition metal. The tetraanionic pincer ligand metal-oxo-alkylidene complex, a trianionic OCO pincer ligand metal complex, or a trianionic ONO pincer ligand metal complex can be used to polymerize cycloalkenes. The poly(cycloalkene)s are predominantly cis-alkene macrocyclics.

A pre-catalyst composition comprising: a) a silica support comprising silica wherein an amount of silica is in a range of from about 70 wt. % to about 95 wt. % based upon a total weight of the silica support; b) a titanium-containing compound wherein an amount of titanium is in a range of from about 0.1 wt. % to about 20 wt. % based upon a total weight of the silica within the pre-catalyst composition; c) a chromium-containing compound wherein an amount of chromium is in a range of from about 0.01 wt. % to about 10 wt. % based upon a total weight of the silica within the pre-catalyst composition; d) a surfactant wherein the surfactant comprises a non-ionic surfactant, a cationic surfactant, or a combination thereof; e) a carboxylate wherein the carboxylate comprises a multi carboxylate, an alpha-hydroxy carboxylate, or a combination thereof; and f) a solvent.

A pre-catalyst composition comprising: a) a silica support comprising silica wherein an amount of silica is in a range of from about 70 wt. % to about 95 wt. % based upon a total weight of the silica support; b) a titanium-containing compound wherein an amount of titanium is in a range of from about 0.1 wt. % to about 20 wt. % based upon a total weight of the silica within the pre-catalyst composition; c) a chromium-containing compound wherein an amount of chromium is in a range of from about 0.01 wt. % to about 10 wt. % based upon a total weight of the silica within the pre-catalyst composition; d) a surfactant wherein the surfactant comprises a non-ionic surfactant, a cationic surfactant, or a combination thereof; e) a carboxylate wherein the carboxylate comprises a multi carboxylate, an alpha-hydroxy carboxylate, or a combination thereof; and f) a solvent.

A method for an olefin polymerization catalyst comprises contacting a silica support or a chromium-silica support with titanium to produce a Cr/Si—Ti catalyst. A titanium-containing solution is used to facilitate the association of titanium with the support, wherein the titanium-containing solution is formed by contacting a solvent, an amino acid, optionally a peroxide, optionally a carboxylate and a titanium-containing compound. A method for preparation of an olefin polymerization catalyst comprises contacting a chromium-silica support with the titanium-containing solution under conditions suitable to form a pre-catalyst composition and further processing the pre-catalyst composition to produce a Cr/Si—Ti catalyst. A method for preparation of an olefin polymerization catalyst comprises contacting a silica support with the titanium-containing solution and a chromium-containing compound under conditions suitable to form a pre-catalyst composition and further processing the pre-catalyst composition to produce a Cr/Si—Ti catalyst.

A method for an olefin polymerization catalyst comprises contacting a silica support or a chromium-silica support with titanium to produce a Cr/Si—Ti catalyst. A titanium-containing solution is used to facilitate the association of titanium with the support, wherein the titanium-containing solution is formed by contacting a solvent, an amino acid, optionally a peroxide, optionally a carboxylate and a titanium-containing compound. A method for preparation of an olefin polymerization catalyst comprises contacting a chromium-silica support with the titanium-containing solution under conditions suitable to form a pre-catalyst composition and further processing the pre-catalyst composition to produce a Cr/Si—Ti catalyst. A method for preparation of an olefin polymerization catalyst comprises contacting a silica support with the titanium-containing solution and a chromium-containing compound under conditions suitable to form a pre-catalyst composition and further processing the pre-catalyst composition to produce a Cr/Si—Ti catalyst.

A pre-catalyst composition comprising: a) a silica support comprising silica wherein an amount of silica is in a range of from about 70 wt. % to about 95 wt. % based upon a total weight of the silica support; b) a titanium-containing compound wherein an amount of titanium is in a range of from about 0.1 wt. % to about 10 wt. % based upon the total weight of the silica support; c) a chromium-containing compound wherein an amount of chromium is in a range of from about 0.1 wt. % to about 10 wt. % based upon the total weight of the silica support; d) a surfactant wherein the surfactant comprises a non-ionic surfactant, a cationic surfactant, or a combination thereof; e) a carboxylate wherein the carboxylate comprises a multi carboxylate, an alpha-hydroxy carboxylate, or a combination thereof; and f) a solvent.