Catalysts for oxidative esterification can be used, for example, fro converting (meth)acrolein to methyl (meth)acrylate. The catalysts are especially notable for high mechanical and chemical stability even over very long time periods, including activity and/or selectivity relatively in continuous operation in media having even a small water content.

A tableted catalyst support, characterized by an alpha-alumina content of at least 85 wt.-%, a pore volume of at least 0.40 mL/g, as determined by mercury porosimetry, and a BET surface area of 0.5 to 5.0 m.sup.2/g. The tableted catalyst support is an alpha-alumina catalyst support obtained with high geometrical precision and displaying a high overall pore volume, thus allowing for impregnation with a high amount of silver, while exhibiting a surface area sufficiently large so as to provide optimal dispersion of catalytically active species, in particular metal species. The invention further provides a process for producing a tableted alpha-alumina catalyst support, which comprises i) forming a free-flowing feed mixture comprising, based on inorganic solids content, at least 50 wt.-% of a transition alumina; ii) tableting the free-flowing feed mixture to obtain a compacted body; and iii) heat treating the compacted body at a temperature of at least 1100° C., preferably at least 1300° C., more preferably at least 1400° C., in particular at least 1450° C., to obtain the tableted alpha-alumina catalyst support. The invention moreover relates to a compacted body obtained by tableting a free-flowing feed mixture which comprises, based on inorganic solids content, at least 50 wt.-% of a transition alumina having a loose bulk density of at most 600 g/L, a pore volume of at least 0.6 mL/g, as determined, and a median pore diameter of at least 15 nm. The invention moreover relates to a shaped catalyst body for producing ethylene oxide by gas-phase oxidation of ethylene, comprising at least 15 wt.-% of silver, relative to the total weight of the catalyst, deposited on the tableted alpha-alumina catalyst support. The invention moreover relates to a process for producing ethylene oxide by gas-phase oxidation of ethylene, comprising reacting ethylene and oxygen in the presence of the shaped catalyst body.

A honeycomb-structured catalyst for decomposing an organic substance, which includes a catalyst particle. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least of Ba and Sr, the B contains Zr, the M is at least one of Mn, Co, Ni, and Fe, y+z=1, 1.001≤x≤1.05, 0.05≤z≤0.2, and w is a positive value that satisfies electrical neutrality. The toluene decomposition rate is greater than 90% when toluene is decomposed using the honeycomb-structured catalyst subjected to a heat treatment at 1200° C. for 48 hours and a gas that contains 50 ppm toluene, 80% nitrogen, and 20% oxygen as a volume concentration as a target at a space velocity of 30,000/h and a catalyst temperature of 400° C.

A composition for exhaust gas purification containing Y—Mn—O and Al.sub.2O.sub.3 and having a specific surface area (SSA) retention satisfying inequality (1) SSA retention (%) >−61.54×(Y—Mn—O ratio)+75.55 and inequality (2) SSA retention (%) >45 (2), where SSA retention is represented by (SSA after aging)/(initial SSA)×100 (%). The SSA after aging and the initial SSA are as defined in the description. The Y—Mn—O ratio is a mass ratio of Y—Mn—O to the sum of Y—Mn—O and Al.sub.2O.sub.3 in the composition for exhaust gas purification, being represented by Y—Mn—O/(Y—Mn—O+Al.sub.2O.sub.3).

A process for producing a silver-based epoxidation catalyst, comprising i) impregnating a particulate porous refractory support with a first aqueous silver impregnation solution comprising silver ions and an aminic complexing agent selected from amines, alkanolamines and amino acids; ii) converting at least part of the silver ions impregnated on the refractory support to metallic silver by heating while directing a stream of a first gas over the impregnated refractory support to obtain an intermediate catalyst, wherein the first gas comprises at least 5 vol.-% oxygen; iii) impregnating the intermediate catalyst with a second aqueous silver impregnation solution comprising silver ions, an aminic complexing agent selected from amines, alkanolamines and amino acids, and one or more transition metal promoters, in particular rhenium; and iv) converting at least part of the silver ions impregnated on the intermediate catalyst to metallic silver by heating while directing a stream of a second gas over the impregnated intermediate catalyst to obtain the epoxidation catalyst, wherein the second gas comprises at most 2.0 vol.-% oxygen, wherein the impregnated refractory support and the impregnated intermediate catalyst are each heated to a temperature of 200 to 800° C. The process of the invention surprisingly allows for obtaining a catalyst with high selectivity in a cost-efficient manner. The invention also relates to a silver-based epoxidation catalyst obtainable by such a process, and to a process for producing an alkylene oxide by gas-phase oxidation of an alkylene, comprising reacting an alkylene and oxygen in the presence of a silver-based epoxidation catalyst obtainable by the above process.

A supported catalyst for decomposing an organic substance that includes a support and a catalyst particle supported on the support. The catalyst particle contains a perovskite-type composite oxide represented by A.sub.xB.sub.yM.sub.zO.sub.w, where the A contains at least one selected from Ba and Sr, the B contains Zr, the M is at least one selected from Mn, Co, Ni and Fe, y+z=1, x≥0.995, z≤0.4, and w is a positive value satisfying electrical neutrality. A film thickness of a catalyst-supporting film supported on the support and containing the catalyst particle is 5 μm or more, or a supported amount as determined by normalizing a mass of the catalyst particle supported on the support by a volume of the support is 45 g/L or more.

Disclosed herein are methods of using scaled selectivities to assist in determining whether changes to the value of a target ethylene oxide production parameter—such as ethylene oxide production rate—used in the process of epoxidizing ethylene with a high-selectivity catalyst, have caused the process to move away from optimal operation. If the deviation from optimal operation has not worsened, it is generally unnecessary to perform a full optimization study even if the value of a target ethylene oxide production parameter has changed, which reduces or eliminates process disturbances caused by carrying out such studies. Methods are also disclosed which use both scaled selectivities and scaled reaction temperatures. If scaled selectivities reveal that a change in the value of a target ethylene oxide production parameter has moved the process away from optimal operation, scaled reaction temperatures can, under certain conditions, provide an indication of the directions in which the reaction temperature and/or overall catalyst chloriding effectiveness should be changed to move toward optimal operation. If a change in the value of a target ethylene oxide production parameter has improved the scaled selectivity, the scaled reaction temperature may also be used to guide further adjustments which may further improve scaled selectivity.

Zero-Rare Earth Metal (ZREM) and Zero-platinum group metals (ZPGM) compositions of varied binary spinel oxides are disclosed as oxygen storage material (OSM) to be used within TWC systems. The ZREM-ZPGM OSM systems comprise binary non-Cu spinel oxides of Co—Fe, Fe—Mn, Co—Mn, or Mn—Fe. The oxygen storage capacity (OSC) property associated with the non-Cu ZREM-ZPGM OSM systems is determined employing isothermal OSC oscillating condition testing. Further, the OSC test results compare the OSC properties of a ZREM-ZPGM reference OSM system including a Cu—Mn binary spinel oxide and PGM reference catalysts including Ce-based OSMs. The non-Cu spinel oxides ZREM-ZPGM OSM systems exhibit significantly improved OSC properties, which are greater than the OSC property of the Ce-based OSM PGM reference systems.

An exhaust gas treatment device capable of treating exhaust gas of a gas turbine or a gas engine includes an exhaust gas treatment catalyst comprising a perovskite composite oxide containing at least Ag and Dy in an A site and at least Mn in a B site.

The present invention relates to a high-performance polyoxometalate catalyst and a method of preparing the same. More particularly, the present invention provides a high-performance polyoxometalate catalyst, the activity and selectivity of which may be improved by controlling the content of vanadium and the like and which has superior reproducibility and may unsaturated carboxylic acid from unsaturated aldehyde in a high yield for a long time, a method of preparing the same, and the like.