Abstract: In a method for producing hydrogen cyanide by passing a feed mixture comprising ammonia and methane through reaction tubes, coated on the inner surface with a catalyst comprising platinum, at a reaction temperature of 1000° C. to 1400° C., operated for a time period of at least 100 h, the concentration difference between the ammonia concentration and the methane concentration in the product gas mixture is maintained in a range of from 1.05 % by volume to 3.0% by volume for at least 80% of the time.

Abstract: The reaction tube for preparing hydrogen cyanide comprises a cylindrical tube composed of ceramic, a catalyst comprising platinum applied to the inner wall of the tube and also at least one insert composed of ceramic, having three or four fins pointing from the tube axis to the inner wall of the tube, which is inserted into the cylindrical tube, wherein the fins divide the tube interior space into substantially straight channels with substantially identical circle segment cross sections and wherein the mean gap between the ends of the fins and the inner wall of the tube is in the range of 0.1 to 3 mm. In the method for preparing hydrogen cyanide, ammonia and at least one aliphatic hydrocarbon having 1 to 4 carbon atoms are reacted in the reaction tube at 1000 to 1400° C.

Abstract: In a method for producing hydrogen cyanide by passing a feed mixture comprising ammonia and methane through reaction tubes, coated on the inner surface with a catalyst comprising platinum, at a reaction temperature of 1000° C. to 1400° C., operated for a time period of at least 100 h, the concentration difference between the ammonia concentration and the methane concentration in the product gas mixture is maintained in a range of from 1.05 % by volume to 3.0% by volume for at least 80% of the time.

Abstract: The present invention relates to a process for preparing acrolein from propylene by catalytic gas phase oxidation with molecular oxygen (for example air). The invention further relates to the use of particular propylene-containing starting materials, for example refinery grade propylene, for preparation of acrolein.

Abstract: The reaction tube for preparing hydrogen cyanide comprises a cylindrical tube composed of ceramic, a catalyst comprising platinum applied to the inner wall of the tube and also at least one insert composed of ceramic, having three or four fins pointing from the tube axis to the inner wall of the tube, which is inserted into the cylindrical tube, wherein the fins divide the tube interior space into substantially straight channels with substantially identical circle segment cross sections and wherein the mean gap between the ends of the fins and the inner wall of the tube is in the range of 0.1 to 3 mm. In the method for preparing hydrogen cyanide, ammonia and at least one aliphatic hydrocarbon having 1 to 4 carbon atoms are reacted in the reaction tube at 1000 to 1400° C.

Abstract: The reaction tube comprises a cylindrical ceramic tube and a catalyst comprising platinum applied to the inner surface of the tube, wherein the reaction tube has fins on the inner surface which run in the longitudinal direction of the tube, extend into the interior space of the reaction tube and are coated with catalyst. The reaction tube is suitable for preparing hydrogen cyanide by reacting ammonia and at least one aliphatic hydrocarbon having 1 to 4 carbon atoms at a temperature of 1000 to 1400° C.

Abstract: The present invention relates to a process for preparing acrolein from propylene by catalytic gas phase oxidation with molecular oxygen (for example air). The invention further relates to the use of particular propylene-containing starting materials, for example refinery grade propylene, for preparation of acrolein.

Abstract: A reactive rectification column suitable for the production of 2-hydroxy-4-methylmercaptobutyric acid and/or methionine contains a weir having a height of 100 mm or more.

Abstract: A reactive rectification column suitable for the production of 2-hydroxy-4-methylmercaptobutyric acid and/or methionine contains a weir having a height of 100 mm or more.