Abstract: A coated catalyst which consists of a hollow cylindrical carrier and a catalytically active oxide material applied to the outer surface of the carrier, the applied catalytically active oxide material being applied in a coat thickness of from 10 to 1000 &mgr;m, and having a specific catalytic surface area of from 20 to 30 m2/g and an abrasion of <10, preferably <5, particularly preferably <0.5, % by weight in the turntable abrasion test.

Abstract: A coated catalyst which consists of a hollow cylindrical carrier and a catalytically active oxide material applied to the outer surface of the carrier, the applied catalytically active oxide material being applied in a coat thickness of from 10 to 1000 .mu.m, and having a specific catalytic surface area of from 20 to 30 m.sup.2 /g and an abrasion of <10, preferably <5, particularly preferably <0,5, % by weight in the turntable abrasion test. The catalyst is useful in the preparation of acrylic acid by the gas phase oxidation of acroleins.

Abstract: Supported catalysts which are suitable for ammonoxidation, comprisinga) a spherical or approximately spherical support material which essentially comprises aluminum oxide, silicon dioxide, titanium dioxide and/or zirconium dioxide and whose bulk density is from 0.6 to 1.2 kg/l, andb) an active material which comprises, as essential components, vanadium and antimony in oxidic form.

Abstract: Moldings which comprise from 30 to 100% by weight of graphite, prepared from graphite powders which comprise from 5 to 100% by weight of rhombohedral crystalline graphite and, if required, contain additives and/or binders, and a process for their preparation and their use as catalyst carriers, heat transfer material, column packing or diluent in catalyst beds.

Abstract: A catalyst which consists of a carrier and a catalytically active oxide material applied to the surface of the carrier is prepared by a process in which the carrier is first moistened with, as an adhesive liquid, an aqueous solution of an organic substance boiling at above 100.degree. C. at atmospheric pressure and a layer of active oxide material is then bonded to the surface of the moistened carrier by bringing it into contact with dry, finely divided active oxide material and the adhesive liquid is then removed from the moistened carrier coated with active oxide material.

Abstract: In a process for the preparation of catalytically active poly-metal oxide materials containing Mo and V, a catalyst intermediate is calcined at from 300.degree. to 450.degree. C. in a gas atmosphere which, in addition to inert gases and/or steam, consists of from 0.5 to 4% by volume of O.sub.2 and, averaged over the calcination time, from 1 to 8% by volume of NH.sub.3.

Abstract: A process for regenerating spent multimetal oxide oxidation catalysts from the catalytic gas-phase oxidation of lower organic compounds and which, in fresh form, contain as basic constituents the elements Mo, W, V and Cu in oxidic form, by the action of oxidizing agents or means and solubilizing, aqueous ammonia to which acetic acid and/or the ammonium salt thereof has been added, with subsequent drying and calcination, comprises quantitatively determining the content of metallic constituents during the process and making this content up to the respective original value.

Abstract: Multimetal oxide compositions which comprise, as basic constituents, the elements Mo, V, W, Cu and Ni in oxidic form in certain molar ratios, and the preparation of these multimetal oxide compositions, and their use as catalysts for the gas-phase catalytical oxidation of acrolein to acrylic acid.

Abstract: Multimetal oxide compositions which comprise, as basic constituents, the elements Mo, V, W, Cu and Ni in oxidic form in certain molar ratios, and the preparation of these multimetal oxide compositions, and their use as catalysts for the gas-phase catalytical oxidation of acrolein to acrylic acid.