The invention relates to polyoxometalates represented by the formula (A.sub.n).sup.m+{M′.sub.s[M″M.sub.12X.sub.8O.sub.yR.sub.zH.sub.q]}.sup.m− or solvates thereof, corresponding supported polyoxometalates, and processes for their preparation, as well as corresponding metal-clusters, optionally in the form of a dispersion in a liquid carrier medium or immobilized on a solid support, and processes for their preparation, as well as their use in reductive conversion of organic substrate.

A method for lowering the sodium content of different carriers which may have different physical properties as well as varying degrees of sodium is provided. The method, which lowers the sodium content from the surface, subsurface as well as the binding layer of the carrier, includes contacting a carrier with water. A rinse solution is recovered from the contacting. The rinse solution includes leached sodium from the carrier. The sodium content in the rinse solution is then determined. The contacting, recovering and determining are repeated until a steady state in the sodium content is achieved.

A process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising: directing a feed comprising gaseous ethylene and gaseous oxygen through a packing of individual shaped catalyst bodies, under conditions conducive to obtain a reaction mixture containing at least 2.7 vol.-% of ethylene oxide, wherein each shaped catalyst body comprises silver deposited on a refractory support and is characterized by a content of at least 20 wt.-% of silver, relative to the total weight of the shaped catalyst body; a BET surface area in the range of 1.6 to 3.0 m.sup.2/g; a first face side surface, a second face side surface and a circumferential surface with a plurality of passageways extending from the first face side surface to the second face side surface; and a uniform multilobed cross-section; and a longest direct diffusion pathway d, with 2d being in the range of 0.7 to 2.4 mm, wherein the longest diffusion pathway d is defined as the shortest distance from the geometric surface of the shaped catalyst body to a point inside the structure of the shaped catalyst body for which point the shortest distance is the largest among all points. The process allows for increased activity and/or stability of the catalyst while maintaining or increasing selectivity at high productivity.

A shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, comprising silver deposited on a porous refractory support, the shaped catalyst body having a first face side surface, a second face side surface and a circumferential surface, characterized by a content of at least 20 wt.-% of silver, relative to the total weight of the shaped catalyst body; a multilobe structure; a plurality of passageways extending from the first face side surface to the second face side surface, outer passageways being arranged around a central passageway with one outer passageway being assigned to each lobe, wherein neighboring outer passageways are arranged essentially equidistantly to each other and the outer passageways are arranged essentially equidistantly to the central passageway; a minimum wall thickness A between two neighboring passageways in the range of 0.6 to 1.3 mm; a minimum wall thickness B between each outer passageway and the circumferential surface in the range of 1.1 to 1.8 mm; and a BET surface area in the range of 1.6 to 3.0 m.sup.2/g. The shaped catalyst bodies allow for a favorable balance between mechanical stability, pressure drop and selectivity. The invention also relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of a shaped catalyst body as defined above. The invention further relates to a process for preparing a shaped catalyst body as above, comprising i) impregnating a refractory support having a BET surface area in the range of 1.4 to 2.5 m.sup.2/g with a silver impregnation solution; and ii) subjecting the impregnated refractory support to a calcination process; wherein steps i) and ii) are optionally repeated.

Disclosed is a catalyst system, its methods of preparation and its use for producing, among others, alkenes and/or saturated or unsaturated oxygenates and, which include at least one of an aldehyde and an acid (such as propyl aldehyde, acrolein, acrylic acid, isobutyl aldehyde, methacrolein, methacrylic acid), comprising subjecting the corresponding an alcohol or a diol selected from the group consisting of propanol, propanediol and isobutanol that is derivable from biomass, to a vapor phase process over the catalytic system described herein in the presence of a gas mixture of oxygen, air or nitrogen and/or other suitable diluting gas. In the case where one of 1-propanol, or 1,2-propanediol or 1,3-propanediol or a mixture thereof is subjected to a vapor phase catalytic process over the said catalytic system in the presence of air or oxygen, and a co-fed gas, such as nitrogen or other diluting gas, the product is at least one of propylene, propyl aldehyde, acrolein and acrylic acid. In the case where isobutanol is subjected to such a process, the product is at least one of isobutylene, isobutyl aldehyde, methacrolein and methacrylic acid. The catalyst system comprises a single catalytic zone or multi-catalytic zones, in each of which the composition of the co-feed and other reaction parameter can be independently controlled.

A shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, having a BET surface area in the range of 2 to 20 m2/g and comprising silver and a rhenium promotor deposited on a porous alpha-alumina catalyst support, characterized in that the support has a calcination history of at least 1460° C. The catalyst support has a high surface area and little ethylene oxide isomerization and/or decomposition activity. The invention further relates to a porous alpha-alumina catalyst support having a BET surface area of 1.7 to 10 m2/g, the porous alpha-alumina catalyst support being obtainable by a) preparing a precursor material comprising a transition alumina and/or an alumina hydrate; b) forming the precursor material into shaped bodies; and c) calcining the shaped bodies at a temperature of 1460° C. to 1700° C. to obtain the porous alpha-alumina support. The invention also relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of a shaped catalyst body as described above.

A shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, having a BET surface area in the range of 2 to 20 m2/g and comprising silver and a rhenium promotor deposited on a porous alpha-alumina catalyst support, characterized in that the support has a calcination history of at least 1460° C. The catalyst support has a high surface area and little ethylene oxide isomerization and/or decomposition activity. The invention further relates to a porous alpha-alumina catalyst support having a BET surface area of 1.7 to 10 m2/g, the porous alpha-alumina catalyst support being obtainable by a) preparing a precursor material comprising a transition alumina and/or an alumina hydrate; b) forming the precursor material into shaped bodies; and c) calcining the shaped bodies at a temperature of 1460° C. to 1700° C. to obtain the porous alpha-alumina support. The invention also relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of a shaped catalyst body as described above.

A nanocomposite catalyst includes a support, a multiplicity of nanoscale metal oxide clusters coupled to the support, and one or more metal atoms coupled to each of the nanoscale metal oxide clusters. Fabricating a nanocomposite catalyst includes forming nanoscale metal oxide clusters including a first metal on a support, and depositing one or more metal atoms including a second metal on the nanoscale metal oxide clusters. The nanocomposite catalyst is suitable for catalyzing reactions such as CO oxidation, water-gas-shift, reforming of CO.sub.2 and methanol, and oxidation of natural gas.

A mesoporous mixed oxide catalyst that comprises silicon and at least one metal M that is selected from the group that consists of the elements of groups 4 and 5 of the periodic table and mixtures thereof, with the mass of metal M being between 0.1 and 20% of the mixed oxide mass.

A supported catalyst for decomposing an organic substance that includes a carrier and catalyst particles supported on the carrier. The catalyst particles contain a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where A contains at least one of Ba and Sr, B contains Zr, M is at least one of Mn, Co, Ni, and Fe, y+z=1, x>1, z<0.4, and w is a positive value that satisfies electrical neutrality. An organic substance decomposition rate after the supported catalyst is subjected to a heat treatment at 950° C. for 48 hours is greater than 0.97 when the organic substance decomposition rate before the heat treatment is regarded as 1, and an amount of the catalyst particles peeled off when the supported catalyst is ultrasonicated in water at 28 kHz and 220 W for 15 minutes is less than 1 wt % of the catalyst particles before untrasonication.