A method comprising a) contacting a solvent, a carboxylic acid, and a peroxide-containing compound to form an acidic mixture wherein a weight ratio of solvent to carboxylic acid in the acidic mixture is from about 1:1 to about 100:1; b) contacting a titanium-containing compound and the acidic mixture to form a solubilized titanium mixture wherein an equivalent molar ratio of titanium-containing compound to carboxylic acid in the solubilized titanium mixture is from about 1:1 to about 1:4 and an equivalent molar ratio of titanium-containing compound to peroxide-containing compound in the solubilized titanium mixture is from about 1:1 to about 1:20; and c) contacting a chromium-silica support comprising from about 0.1 wt. % to about 20 wt. % water and the solubilized titanium mixture to form an addition product and drying the addition product by heating to a temperature in a range of from about 50° C. to about 150° C. and maintaining the temperature in the range of from about 50° C. to about 150° C. for a time period of from about 30 minutes to about 6 hours to form a pre-catalyst.

Disclosed is a polyoxometalate compound including a metal-substituted polyoxometalate. The metal-substituted polyoxometalate includes a polyoxometalate having defect sites, a substituting metal atom introduced into the defect sites, and an organic ligand. The substituting metal atom is divalent platinum or palladium. The organic ligand may be a bidentate ligand having an aliphatic heterocycle containing two nitrogen atoms coordinately bonded to the substituting metal atom. One substituting metal atom is introduced into one defect site.

Disclosed is a polyoxometalate compound including a metal-substituted polyoxometalate. The metal-substituted polyoxometalate includes a polyoxometalate having defect sites, a substituting metal atom introduced into the defect sites, and an organic ligand. The substituting metal atom is divalent platinum or palladium. The organic ligand may be a bidentate ligand having an aliphatic heterocycle containing two nitrogen atoms coordinately bonded to the substituting metal atom. One substituting metal atom is introduced into one defect site.

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.

Methods for synthesizing a water-soluble titanium-silicon complex are disclosed herein. The titanium-silicon complex can be utilized to produce titanated solid oxide supports and titanated chromium supported catalysts. The titanated chromium supported catalysts subsequently can be used to polymerize olefins to produce, for example, ethylene based homopolymer and copolymers.

A method comprising a) contacting a solvent, a carboxylic acid, and a peroxide-containing compound to form an acidic mixture wherein a weight ratio of solvent to carboxylic acid in the acidic mixture is from about 1:1 to about 100:1; b) contacting a titanium-containing compound and the acidic mixture to form a solubilized titanium mixture wherein an equivalent molar ratio of titanium-containing compound to carboxylic acid in the solubilized titanium mixture is from about 1:1 to about 1:4 and an equivalent molar ratio of titanium-containing compound to peroxide-containing compound in the solubilized titanium mixture is from about 1:1 to about 1:20; and c) contacting a chromium-silica support comprising from about 0.1 wt. % to about 20 wt. % water and the solubilized titanium mixture to form an addition product and drying the addition product by heating to a temperature in a range of from about 50° C. to about 150° C. and maintaining the temperature in the range of from about 50° C. to about 150° C. for a time period of from about 30 minutes to about 6 hours to form a pre-catalyst.

A method comprising a) contacting a solvent, a carboxylic acid, and a peroxide-containing compound to form an acidic mixture wherein a weight ratio of solvent to carboxylic acid in the acidic mixture is from about 1:1 to about 100:1; b) contacting a titanium-containing compound and the acidic mixture to form a solubilized titanium mixture wherein an equivalent molar ratio of titanium-containing compound to carboxylic acid in the solubilized titanium mixture is from about 1:1 to about 1:4 and an equivalent molar ratio of titanium-containing compound to peroxide-containing compound in the solubilized titanium mixture is from about 1:1 to about 1:20; and c) contacting a chromium-silica support comprising from about 0.1 wt. % to about 20 wt. % water and the solubilized titanium mixture to form an addition product and drying the addition product by heating to a temperature in a range of from about 50° C. to about 150° C. and maintaining the temperature in the range of from about 50° C. to about 150° C. for a time period of from about 30 minutes to about 6 hours to form a pre-catalyst.

The present disclosure provides a method and a catalyst for selective oligomerization of ethylene. The raw material for the catalyst consists of a dehydropyridine annulene-type ligand, a transition metal compound, and an organometallic compound in a molar ratio of 1:0.5-100:0.1-5000. The present disclosure also provides a method for selective oligomerization of ethylene accomplished by using the above-mentioned catalyst. The catalyst for selective oligomerization of ethylene has high catalytic activity, high selectivity for the target products 1-hexene and 1-octene, and low selectivity for 1-butene and 1-C.sub.10.sup.+.

The present disclosure provides a method and a catalyst for selective oligomerization of ethylene. The raw material for the catalyst consists of a dehydropyridine annulene-type ligand, a transition metal compound, and an organometallic compound in a molar ratio of 1:0.5-100:0.1-5000. The present disclosure also provides a method for selective oligomerization of ethylene accomplished by using the above-mentioned catalyst. The catalyst for selective oligomerization of ethylene has high catalytic activity, high selectivity for the target products 1-hexene and 1-octene, and low selectivity for 1-butene and 1-C.sub.10.sup.+.

Methods for synthesizing a water-soluble titanium-silicon complex are disclosed herein. The titanium-silicon complex can be utilized to produce titanated solid oxide supports and titanated chromium supported catalysts. The titanated chromium supported catalysts subsequently can be used to polymerize olefins to produce, for example, ethylene based homopolymer and copolymers.