The present invention relates to a catalyst system for olefin metathesis, the catalyst system comprising: a) a first system zone substantially comprising a layered double hydroxide; and b) a second system zone comprising a metathesis catalyst.

The present invention relates to a catalyst system for olefin metathesis, the catalyst system comprising: a) a first system zone substantially comprising a layered double hydroxide; and b) a second system zone comprising a metathesis catalyst.

A catalyst and corresponding methods of using a catalyst are provided that can be beneficial for conversion of paraffins into a product stream enriched in aromatics and/or methane while reducing or minimizing the content of ethane in the product stream. Such catalysts and methods can be useful, for example, for processing a raw gas, associated gas, tail gas, natural gas, or other type of methane-containing feed stream to convert C.sub.2+ hydrocarbons in the stream to heavier hydrocarbons and methane while reducing or minimizing content of ethane in the products from the conversion reaction. Such conversion can be useful for upgrading a methane-containing feed stream to have an energy content that is suitable for pipeline transport under one or more specifications for transport of natural gas. The catalyst and corresponding method can also be beneficial when used as a second stage catalyst in a configuration involving multiple conversion stages.

A catalyst and corresponding methods of using a catalyst are provided that can be beneficial for conversion of paraffins into a product stream enriched in aromatics and/or methane while reducing or minimizing the content of ethane in the product stream. Such catalysts and methods can be useful, for example, for processing a raw gas, associated gas, tail gas, natural gas, or other type of methane-containing feed stream to convert C.sub.2+ hydrocarbons in the stream to heavier hydrocarbons and methane while reducing or minimizing content of ethane in the products from the conversion reaction. Such conversion can be useful for upgrading a methane-containing feed stream to have an energy content that is suitable for pipeline transport under one or more specifications for transport of natural gas. The catalyst and corresponding method can also be beneficial when used as a second stage catalyst in a configuration involving multiple conversion stages.

A catalyst composition comprising a mixture of (a) a zeolite compound in an amount of from 10% to 60% by weight, wherein the zeolite compound comprises cations selected from Fe.sup.2+, Fe.sup.3+, Cu.sup.+, Cu.sup.2+ or mixtures thereof, and (b) a ceria/zirconia/alumina composite oxide, wherein the alumina content in said composite oxide is in the range of 20 to 80% by weight, in particular of 40 to 60% by weight,
a catalyst comprising such catalyst composition and its use for exhaust gas after-treatment of diesel and lean burn engines.

According to one or more embodiments described, a zeolite supported catalyst may be synthesized by a process that includes combining a colloidal mixture with a metal oxide support material to form a support precursor material, processing the support precursor material to form a support material, and impregnating the support material with one or more metals to form the zeolite supported catalyst. The colloidal mixture may include nano-sized zeolite crystals, and the nano-sized zeolite crystals may have an average size of less than 100 nm.

A catalyst comprises a carbide or nitride of a metal and a promoter element. The metal is selected from the group consisting of Mo, W, Co, Fe, Rh or Mn, and the promoter element is selected from the group consisting of Ni, Co, Al, Si, S or P, provided that the metal and the promoter element are different. The catalyst also comprises a mesoporous support having a surface area of at least about 170 m.sup.2 g.sup.−1, wherein the carbide or nitride of the metal and the promoter element is supported by the mesoporous support, and is in a non-sulfided form and in an amorphous form.

A catalyst comprises a carbide or nitride of a metal and a promoter element. The metal is selected from the group consisting of Mo, W, Co, Fe, Rh or Mn, and the promoter element is selected from the group consisting of Ni, Co, Al, Si, S or P, provided that the metal and the promoter element are different. The catalyst also comprises a mesoporous support having a surface area of at least about 170 m.sup.2 g.sup.−1, wherein the carbide or nitride of the metal and the promoter element is supported by the mesoporous support, and is in a non-sulfided form and in an amorphous form.

Embodiments of processes and multiple-stage catalyst systems for producing propylene comprising introducing a hydrocarbon stream comprising 2-butene to an isomerization catalyst zone to isomerize the 2-butene to 1-butene, passing the 2-butene and 1-butene to a metathesis catalyst zone to cross-metathesize the 2-butene and 1-butene into a metathesis product stream comprising propylene and C.sub.4-C.sub.6 olefins, and cracking the metathesis product stream in a catalyst cracking zone to produce propylene. The isomerization catalyst zone comprises a silica-alumina catalyst with a ratio by weight of alumina to silica from 1:99 to 20:80. The metathesis catalyst comprises a mesoporous silica catalyst support impregnated with metal oxide. The catalyst cracking zone comprises a mordenite framework inverted (MFI) structured silica catalyst.

Disclosed are processes for conversion of a feedstock comprising C.sub.8+ aromatic hydrocarbons to lighter aromatic products in which the feedstock and optionally hydrogen are contacted in the presence of the catalyst composition under conversion conditions effective to dealkylate and transalkylate said C.sub.8+ aromatic hydrocarbons to produce said lighter aromatic products comprising benzene, toluene and xylene. The catalyst composition comprises a zeolite, a first metal, and a second metal, and is treated with a source of sulfur and/or a source of steam.