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.

A catalyst comprising molybdenum, bismuth, iron, and nickel, wherein a proportion of a surface concentration of the nickel to a bulk concentration of the nickel is 0.60 to 1.20.

A catalyst comprising molybdenum, bismuth, iron, and nickel, wherein a proportion of a surface concentration of the nickel to a bulk concentration of the nickel is 0.60 to 1.20.

A method for producing xylylenediamine, including performing a first hydrogenation including hydrogenating a mixed solution including dicyanobenzene and a solvent including liquid ammonia in a fixed-bed reactor such that a reaction product (A) is produced, performing ammonia separation including separating and removing liquid ammonia included in the reaction product (A) or a reaction product (D) such that a reaction product (B) or (E) is produced, performing solid-liquid separation including subjecting the reaction product (B) or (A) to solid-liquid separation and removing a solid component such that a reaction product (C) or the reaction product (D) is produced, and performing a second hydrogenation including hydrogenating the reaction product (C) or (E) in a fixed-bed reactor. After the first hydrogenation is performed, the ammonia separation and the solid-liquid separation are performed in this order or reverse order, followed by the second hydrogenation.

A method for producing xylylenediamine, including performing a first hydrogenation including hydrogenating a mixed solution including dicyanobenzene and a solvent including liquid ammonia in a fixed-bed reactor such that a reaction product (A) is produced, performing ammonia separation including separating and removing liquid ammonia included in the reaction product (A) or a reaction product (D) such that a reaction product (B) or (E) is produced, performing solid-liquid separation including subjecting the reaction product (B) or (A) to solid-liquid separation and removing a solid component such that a reaction product (C) or the reaction product (D) is produced, and performing a second hydrogenation including hydrogenating the reaction product (C) or (E) in a fixed-bed reactor. After the first hydrogenation is performed, the ammonia separation and the solid-liquid separation are performed in this order or reverse order, followed by the second hydrogenation.

A process for preparing C.sub.2 to C.sub.5 paraffins includes introducing a feed stream comprising hydrogen gas and a carbon-containing gas into a reaction zone of a reactor, and converting the feed stream into a product stream comprising C.sub.2 to C.sub.5 paraffins in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a metal oxide catalyst component and a microporous catalyst component. The metal oxide catalyst component satisfies: an atomic ratio of Cu/Zn from 0.01 to 3.00; an atomic ratio of Cr/Zn from 0.01 to 1.50; and percentage of (Al+Cr) from greater than 0.0 at % to 50.0 at % based on a total amount of metal in the metal oxide catalyst component.

A process for preparing C.sub.2 to C.sub.5 paraffins includes introducing a feed stream comprising hydrogen gas and a carbon-containing gas into a reaction zone of a reactor, and converting the feed stream into a product stream comprising C.sub.2 to C.sub.5 paraffins in the reaction zone in the presence of a hybrid catalyst. The hybrid catalyst includes a metal oxide catalyst component and a microporous catalyst component. The metal oxide catalyst component satisfies: an atomic ratio of Cu/Zn from 0.01 to 3.00; an atomic ratio of Cr/Zn from 0.01 to 1.50; and percentage of (Al+Cr) from greater than 0.0 at % to 50.0 at % based on a total amount of metal in the metal oxide catalyst component.

A catalyst comprising a carrier and a metals component impregnated in the carrier, the carrier comprising alumina; and the metals component comprising a first metals fraction and a second metals fraction, the first metals fraction comprising at least one metal selected from chromium, molybdenum, or tungsten, and the second metals fraction comprising at least two metals selected from cobalt, rhodium, iridium, nickel, palladium, or platinum, wherein the catalyst has a first pore volume of 0.28 to 0.45 mL/g for pores having a pore diameter of 12 nm to less than 16 nm, and a second pore volume of 0.15 to 0.28 mL/g for pores of 2.0 nm to less than 12.0 nm.

Here disclosed is a composite catalyst for methane cracking and a method of producing the composite catalyst. The composite catalyst includes a substrate formed of metal oxide, and one or more catalytic transition metals solubilized in the metal oxide, wherein the metal oxide includes a metal which differs from the one or more catalytic transition metals, wherein the metal oxide forms a matrix which the one or more catalytic transition metals are solubilized in to render transition metal ions from the one or more catalytic transition metals, wherein the transition metal ions under a reducing atmosphere diffuse to reside as transition metal nanoparticles at a surface of the substrate and the transition metal nanoparticles under an oxidizing atmosphere diffuse away from the surface to reside as transition metal ions in the metal oxide, and wherein the transition metal nanoparticles at the surface induce carbon from the methane cracking to deposit on the transition metal nanoparticles and have the carbon deposited grow away from the substrate.

Here disclosed is a composite catalyst for methane cracking and a method of producing the composite catalyst. The composite catalyst includes a substrate formed of metal oxide, and one or more catalytic transition metals solubilized in the metal oxide, wherein the metal oxide includes a metal which differs from the one or more catalytic transition metals, wherein the metal oxide forms a matrix which the one or more catalytic transition metals are solubilized in to render transition metal ions from the one or more catalytic transition metals, wherein the transition metal ions under a reducing atmosphere diffuse to reside as transition metal nanoparticles at a surface of the substrate and the transition metal nanoparticles under an oxidizing atmosphere diffuse away from the surface to reside as transition metal ions in the metal oxide, and wherein the transition metal nanoparticles at the surface induce carbon from the methane cracking to deposit on the transition metal nanoparticles and have the carbon deposited grow away from the substrate.