9928results about "Heterogenous catalyst chemical elements" patented technology

A process for selective formation of ethanol from acetic acid includes contacting a feed stream containing acetic acid and hydrogen at an elevated temperature with catalyst comprising platinum and tin on a high surface area silica promoted with calcium metasilicate. Selectivities to ethanol of over 85% are achieved at 280° C. with catalyst life in the hundreds of hours.

A two stage hydrodesulfurizing process for producing low sulfur distillates. A distillate boiling range feedstock containing in excess of about 3,000 wppm sulfur is hydrodesulfurized in a first hydrodesulfurizing stage containing one or more reaction zones in the presence of hydrogen and a hydrodesulfurizing catalyst. The liquid product stream thereof is passed to a first separation stage wherein a vapor phase product stream and a liquid product stream are produced. The liquid product stream, which has a substantially lower sulfur and nitrogen content then the original feedstream is passed to a second hydrodesulfurizing stage also containing one or more reaction zones where it is reacted in the presence of hydrogen and a second hydrodesulfurizing catalyst at hydrodesulfurizing conditions. The catalyst in any one or more reaction zones is a bulk multimetallic catalyst comprised of at least one Group VIII non-noble metal and at least two Group VIB metals.

Metal oxide catalysts comprising various dopants are provided. The catalysts are useful as heterogenous catalysts in a variety of catalytic reactions, for example, the oxidative coupling of methane to C2 hydrocarbons such as ethane and ethylene. Related methods for use and manufacture of the same are also disclosed.

Liquid feed flame spray pyrolysis of solutions of a metal oxide precursor which is an alkoxide or C1-6 carboxylate and at least one second metal oxide precursor and / or second metal compound dissolved in oxygenated solvent by combustion with oxygen lead to the formation of sub-micron mixed-metal oxide powders not accessible by other processes or by the pyrolysis of metal chlorides or nitrates. The powders have numerous uses in advanced materials applications including particulate solid state lasers, advanced ceramic materials, and as catalysts in organic synthesis and automobile exhaust systems.

Disclosed is a catalyst. The catalyst comprises palladium, gold, and a support comprising titanium dioxide and tungsten trioxide. The support preferably comprises from 75 wt % to 99 wt % of titanium dioxide and from 1 wt % to 25 wt % of tungsten trioxide. A method for preparing the catalyst is also disclosed. The method comprises impregnating the support with a palladium compound and a gold compound, calcining the impregnated support, and then reducing the calcined support. Further disclosed is a method for preparing vinyl acetate with the catalyst. The catalyst exhibits improved catalytic activity and selectivity.

Ink compositions with modified properties result from using a powder size below 100 nanometers. Colored inks are illustrated. Nanoscale coated, uncoated, whisker inorganic fillers are included. The pigment nanopowders taught comprise one or more elements from the group actinium, aluminum, antimony, arsenic, barium, beryllium, bismuth, cadmuim, calcium, cerium, cesium, chalcogenide, cobalt, copper, dysprosium, erbium, europium, gadolinium, gallium, gold, hafnium, hydrogen, indium, iridium, iron, lanthanum, lithium, magnesium, manganese, mendelevium, mercury, molybdenum, neodymium, neptunium, nickel, niobium, nitrogen, oxygen, osmium, palladium, platinum, potassium, praseodymium, promethium, protactinium, rhenium, rubidium, scandium, silver, sodium, strontium, tantalum, terbium, thallium, thorium, tin, titanium, tungsten, vanadium, ytterbium, yttrium, zinc, and zirconium.

A method of manufacturing a porous sintered body includes mixing at least two groups of silicon carbide particles and a pore forming material having an average particle diameter Y μm to obtain a molding material. The at least two groups of silicon carbide particles have different average particle diameters and have a first group of silicon carbide particles whose blending quantity by weight in the molding material is greatest among the at least two groups of silicon carbide particles. The first group have an average particle diameter X μm. The relationships 15≦X, 0.5·X≦Z≦0.9·X, and 0.8·Z≦Y≦1.8·Z are satisfied, wherein Z μm is an average pore diameter of the porous sintered body no less than 10 μm and no greater than 20 μm.

Perovskite-type catalyst consists essentially of a metal oxide composition is provided. The metal oxide composition is represented by the general formula A.sub.1-x B.sub.x MO.sub.3, in which A is a mixture of elements originally in the form of single phase mixed lanthanides collected from bastnasite; B is a divalent or monovalent cation; M is at least one element selected from the group consisting of elements of an atomic number of from 22 to 30, 40 to 51, and 73 to 80; and x is a number defined by 0.ltoreq.x<0.5.

A catalyst composition and process facilitates the oxidative reforming of low molecular weight hydrocarbons, such as methane, to other hydrocarbons having 2 or more carbon atoms (“C2+ compounds”). Compositions having a formula comprising a metal, tungsten, manganese and oxygen effectively catalyze the oxidative reforming of methane with a high rate of conversion and selectivity. Controlling feed gas flow and catalyst bed temperature controls the exothermic OCM reaction, avoiding runaway reactions or coking. A single or multiple reactor system can be utilized for the oxidative reforming reactions. Using two reactors in series, catalyst embodiments produced favorable yields of C2+ compounds, in the presence or absence of a distributed oxygen feed, and with or without interstage effluent cooling. Removal of desirable end products from the reactor effluent, followed by recycling of the residual effluent, increases the conversion to, and ultimate yield of desirable end product.

Provided is an ammonia slip catalyst article having supported palladium in a top or upstream layer for oxidation of carbon monoxide and / or hydrocarbons, an SCR catalyst either in the top layer or in a separate lower or downstream layer, and an ammonia oxidation catalyst in a bottom layer. Also provided are methods for treating an exhaust gas using the catalyst article, wherein the treatment involves reducing the concentrations of ammonia and optionally carbon monoxide and / or hydrocarbons in the exhaust gas.

A catalyst system and process for combined cracking and selective hydrogen combustion of hydrocarbons are disclosed. The catalyst system contains at least one solid acid component and at least one metal-based component which consists of (a) oxygen and / or sulfur and (b) a metal combination selected from the group consisting of: i) at least one metal from Group 3 and at least one metal from Groups 4-15 of the Periodic Table of the Elements; ii) at least one metal from Groups 5-15 of the Periodic Table of the Elements, and at least one metal from at least one of Groups 1, 2, and 4 of the Periodic Table of the Elements; iii) at least one metal from Groups 1 and 2, at least one metal from Group 3, and at least one metal from Groups 4-15 of the Periodic Table of the Elements; and iv) two or more metals from Groups 4-15 of the Periodic Table of the Elements, wherein the at least one of oxygen and sulfur is chemically bound both within and between the metals and, optionally, (3) at least one of at least one support, at least one filler and at least one binder. The process is such that the yield of hydrogen is less than the yield of hydrogen when contacting the hydrocarbons with the solid acid component alone. Further the emissions of NOx from the regeneration cycle of the catalyst system are reduced.

Metal oxide catalysts comprising various dopants are provided. The catalysts are useful as heterogenous catalysts in a variety of catalytic reactions, for example, the oxidative coupling of methane to C2 hydrocarbons such as ethane and ethylene. Related methods for use and manufacture of the same are also disclosed.

An inorganic material that consists of at least two elementary spherical particles, each of said spherical particles comprising metal nanoparticles that are between 1 and 300 nm in size and a mesostructured matrix with an oxide base of at least one element X that is selected from the group that consists of aluminum, titanium, tungsten, zirconium, gallium, germanium, tin, antimony, lead, vanadium, iron, manganese, hafnium, niobium, tantalum, yttrium, cerium, gadolinium, europium and neodymium is described, whereby said matrix has a pore size of between 1.5 and 30 nm and has amorphous walls with a thickness of between 1 and 30 nm, said elementary spherical particles having a maximum diameter of 10 μm. Said material can also contain zeolitic nanocrystals that are trapped within said mesostructured matrix.

The exhaust gas of internal combustion engines operated with a predominantly stoichiometric air / fuel mixture contains, as well as the gaseous hydrocarbon (HC), carbon monoxide (CO) and nitrogen oxide (NOx) pollutants, also ultrafine particulates. The introduction of the EU-5 exhaust gas standard in Europe in 2010 will for the first time impose a legal limit to these particulate emissions for gasoline vehicles. Future exhaust gas cleaning concepts for these vehicles must include devices for removing these particulates.A catalytically active particulate filter, an exhaust gas cleaning system and a process for cleaning the exhaust gases of predominantly stoichiometrically operated internal combustion engines are presented, which are suitable, as well as the gaseous CO, HC and NOx pollutants, also for removing particulates from the exhaust gas. The particulate filter comprises a filter body and a catalytically active coating consisting of two layers. Both layers contain alumina. The first layer contains palladium. The second layer contains rhodium. The latter is disposed above the first layer.

Composite hydrogen transport membranes, which are used for extraction of hydrogen from gas mixtures are provided. Methods are described for supporting metals and metal alloys which have high hydrogen permeability, but which are either too thin to be self supporting, too weak to resist differential pressures across the membrane, or which become embrittled by hydrogen. Support materials are chosen to be lattice matched to the metals and metal alloys. Preferred metals with high permeability for hydrogen include vanadium, niobium, tantalum, zirconium, palladium, and alloys thereof. Hydrogen-permeable membranes include those in which the pores of a porous support matrix are blocked by hydrogen-permeable metals and metal alloys, those in which the pores of a porous metal matrix are blocked with materials which make the membrane impervious to gases other than hydrogen, and cermets fabricated by sintering powders of metals with powders of lattice-matched ceramic.