Abstract: In the production of a catalyst containing a catalytically active Mo--V--O phase, the problem exists of keeping the Mo--V--O phase and/or an Mo--V--Ti--O phase substantially free of other catalytically active impurities in order not to catalyze competing reactions at the same time. For this purpose, the invention provides that vanadium oxide and molybdenum oxide are mixed in a ratio of 0.7 to 1% by weight based on V.sub.2 O.sub.5 and MoO.sub.3, the mixture is heated to a temperature above 500.degree. C., the Mo--V--O phase is cooled, ground and then subjected to a reducing treatment, and dispersed on a heated oxidic support, the dispersed material is then ground, and then applied to a suitable macroscopic support, optionally with further additives, and calcined.

Abstract: Method for the production of catalytically active mixed phases in powder form from precursors which contain the elements of the mixed phase and are treated thermally and mechanically.The precursor or precursors contained in a solution or suspension are applied to heated surfaces of moving heat carrying bodies and precipitated and dissociated on them with evaporation of the solvent or of the liquid component of the suspension. The mixed phase formed on the heat carrying bodies is removed from the heat carrying bodies and then, to prepare it for further use, it is crushed.

Abstract: A process for the catalytic gas-phase oxidation of propene or isobutene to acrolein or methacrolein in a tubular fixed bed reactor or catalytically active oxides with a .gtoreq.90% conversion of the initial olefin on a single passage, wherein the temperature of the gases containing the reactants in the direction of flow along the tubes from their entrance until the conversion of the initial olefin is from 30 to 70% is from 360.degree. to 420.degree. C. and is then adjusted to from 360.degree. to 300.degree. C. until the conversion of the initial olefin is from 80 to 90% and is thereafter maintained at from 330.degree. to 390.degree. C. until the gases emerge from the tubes, is described.

Abstract: An embossed, solid-surface or grid-like metal base structure is degreased and etched and then provided with a vitreous enamel coating, using an enamel which forms a low-porosity bottom layer and a rough top layer of high resistance to acid. The base structure coated with this ground coat of enamel is immersed in a catalyst slip liquefying under the action of shear forces, which is prepared essentially from a powder of the catalytically active compounds, a binding agent, water, and, in some cases, one or more wetting agents. The wetted base structure is removed from the bath while movement of the slip bath is sustained by a stirrer or a vibrator, and then delivered to a drying process. The dried coating of slip can, if necessary, also be calcined and/or impregnated with an alkyl silicate or a solution thereof.

Abstract: A process and apparatus for continuously monitoring of concentrations of gaseous components in gas mixtures, with the exception of O.sub.2. The desired concentration values are obtained simultaneously and separately for the individual gas components, without disruption and with relatively greater accuracy, by a direct path. The concentration of the gaseous component is continuously measured with the aid of at least one electrochemical cell having at least one solid body which contains oxygen-ion-conducting material and a metal-oxide-containing electrode, and generates electrical signals which are a function of the concentration of the component. The measurement signals are electronically and automatically evaluated in a computer which converts them into concentration values. The converted values are compared with reference values of a program which has been programmed into the computer earlier.

Abstract: Method for the selective elimination of nitrogen oxides from flue gases, especially from the flue gases from furnaces.For the denitration, the flue gases are brought together with catalytically active solid bodies through which the flue gases can flow on account of their structural makeup and/or because they are in the form of a loose bed. A reducing agent, mixed if desired with a carrier gas, is brought in contact with the catalytically active solid or sections thereof, in alternation with the flue gases containing the nitrogen oxides that are to be reduced.

Abstract: Selective elimination of nitrogen oxides contained in the exhaust gases from furnaces.With the addition of ammonia to the exhaust gases and acceleration of the reaction by a catalyst, the nitrogen oxides are reduced to molecular nitrogen and water. The procedure is such that the catalyst is traversed in one zone by the exhaust gases and in a zone separate therefrom by the fresh air being fed to the furnace as combustion air, while the position of the zones traversed by the exhaust gases and by the fresh air is changed continuously or step-wise such that the zone first traversed by the exhaust gases is then traversed by fresh air, and vice versa.The ammonia is mixed with the fresh air before it enters the catalyst, bound to the surface of the catalytically active material, and carried along into the zone traversed by the exhaust gases, where the reduction of the nitrogen oxide then takes place.

Abstract: Hard, fracture-resistant catalysts are prepared from zeolites of the pentasil family by a process in which water, organic additives which increase the viscosity and a silicate are added to the zeolite powder, and the material is molded, dried and calcined.The fracture-resistant zeolites obtained are used as catalyst carriers.