Abstract: A catalyst suitable for the gas-phase oxidation of organic compounds to ?,?-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, the starting reaction gas mixture is oxidized over a fixed catalyst bed which consists of at least two fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the transition from temperature zone A to temperature zone B does not spatially coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: A process for preparing shaped catalyst bodies whose active composition is a multielement oxide, in which a finely divided precursor mixture is shaped to a desired geometry with addition of boron nitride and subsequently treated thermally.

Abstract: In a process for the heterogeneously catalyzed gas-phase partial oxidation of precursor compounds of (meth)acrylic acid over a fixed catalyst bed which contains, as a catalyst, a mixed oxide active material shaped into a geometric body, the geometric body is a geometric base body into whose surface a cavity has been introduced.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrylic acid, the propene-containing starting reaction gas mixture is oxidized in a first reaction stage using a fixed catalyst bed 1 which consists of a plurality of fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the acrolein-containing product gas mixture of the first reaction stage is then oxidized in a second reaction stage using a fixed catalyst bed 2 which consists of a plurality of fixed catalyst bed zones and is accommodated in two successive temperature zones C, D, and the transition from one temperature zone to another temperature zone within one reaction stage does not spatially coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid, the starting reaction gas mixture is oxidized over a fixed catalyst bed 1 which consists of at least two fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the transition from temperature zone A to temperature zone B does not coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: The invention relates to a method for the heterogenically catalyed gas-phase partial oxidation of precursor compounds of (meth)acrylic acid in a fixed catalyst bed, containing as the catalyst an activated mass of mixed oxide, shaped to form a geometric body. Said geometric body is a geometric base body, into whose surface a cavity is incorporated.

Abstract: Coated catalysts which are suitable for the gas-phase catalytic oxidation of propene to acrolein are prepared by a process in which rings are used as supports and water is used as a binder.

Abstract: A process for preparing (meth)acrolein and/or (meth)acrylic acid by heterogeneously catalyzed gas phase partial oxidation of an organic precursor compound over a fresh fixed catalyst bed, in which the process is started up at a reduced hourly space velocity of charging gas mixture on the fixed catalyst bed.

Abstract: A process for the catalytic gas-phase oxidation of propene to acrylic acid, in which the reaction gas starting mixture is oxidized, with a high propene loading, in a first reaction stage, over a first fixed-bed catalyst which is housed in two successive reaction zones A, B, the reaction zone B being kept at a higher temperature than the reaction zone A, and the acrolein-containing product gas mixture of the first reaction stage is then oxidized in a second reaction stage, with a high acrolein loading, over a second fixed-bed catalyst which is housed in two successive reaction zones C, D, the reaction zone D being kept at a higher temperature than the reaction zone C.

Abstract: In a process for partially oxidizing acrolein to acrylic acid in the gas phase under heterogeneous catalysis, the starting reaction gas mixture is oxidized at an acrolein loading of ?145 and ?70 l (STP) of acrolein/l of fixed catalyst bed·h over a fixed catalyst bed which is accommodated in two successive reaction zones A, B, the highest temperature of the reaction gas mixture within reaction zone A being above the highest temperature of the reaction gas mixture within reaction zone B.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrylic acid, the starting reaction gas mixture is oxidized at a propene loading of <160 l(STP)/l·h in a first reaction stage over a fixed catalyst bed 1 which is accommodated in two successive reaction zones A, B, and the acrolein-containing product gas mixture of the first reaction stage is subsequently oxidized in a second reaction stage over a fixed catalyst bed 2 which is a accommodated in two successive reaction zones C, D, the highest temperature of the reaction gas mixture within reaction zone A being above the highest temperature of the reaction gas mixture within reaction zone B and the highest temperature of the reaction gas mixture within reaction zone C being above the highest temperature of the reaction gas mixture within reaction zone D.

Abstract: A catalyst suitable for the gas-phase oxidation of organic compounds to ?,?-unsaturated aldehydes and/or carboxylic acids and having an active phase comprising a multimetal oxide material is prepared by a process in which a particulate catalyst precursor which contains oxides and/or compounds of the elements other than oxygen which constitute the multimetal oxide material, which compounds can be converted into oxides, is prepared and said catalyst precursor is converted by calcination into a catalytically active form, wherein a stream of the particulate catalyst precursor is passed at substantially constant speed through at least one calcination zone at constant temperature for calcination.

Abstract: A process for preparing (meth)acrolein and/or (meth)acrylic acid by heterogeneously catalyzed gas phase partial oxidation of an organic precursor compound over a fresh fixed catalyst bed, in which the process is started up at a reduced hourly space velocity of charging gas mixture on the fixed catalyst bed.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of acrolein to acrylic acid, the starting reaction gas mixture is oxidized over a fixed catalyst bed 1 which consists of at least two fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the transition from temperature zone A to temperature zone B does not coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrylic acid, the starting reaction gas mixture is oxidized at a propene loading of <160 l(STP)/l·h in a first reaction stage over a fixed catalyst bed 1 which is accommodated in two successive reaction zones A, B, and the acrolein-containing product gas mixture of the first reaction stage is subsequently oxidized in a second reaction stage over a fixed catalyst bed 2 which is a accommodated in two successive reaction zones C, D, the highest temperature of the reaction gas mixture within reaction zone A being above the highest temperature of the reaction gas mixture within reaction zone B and the highest temperature of the reaction gas mixture within reaction zone C being above the highest temperature of the reaction gas mixture within reaction zone D.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrolein, the starting reaction gas mixture is oxidized over a fixed catalyst bed which consists of at least two fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the transition from temperature zone A to temperature zone B does not spatially coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: In a process for heterogeneously catalyzed partial gas phase oxidation of propene to acrylic acid, the propene-containing starting reaction gas mixture is oxidized in a first reaction stage using a fixed catalyst bed 1 which consists of a plurality of fixed catalyst bed zones and is accommodated in two successive temperature zones A, B, and the acrolein-containing product gas mixture of the first reaction stage is then oxidized in a second reaction stage using a fixed catalyst bed 2 which consists of a plurality of fixed catalyst bed zones and is accommodated in two successive temperature zones C, D, and the transition from one temperature zone to another temperature zone within one reaction stage does not spatially coincide with a transition from one fixed catalyst bed zone to another fixed catalyst bed zone.

Abstract: In a process for partially oxidizing acrolein to acrylic acid in the gas phase under heterogeneous catalysis, the starting reaction gas mixture is oxidized at an acrolein loading of ≦145 and ≧70 l (STP) of acrolein/l of fixed catalyst bed·h over a fixed catalyst bed which is accommodated in two successive reaction zones A, B, the highest temperature of the reaction gas mixture within reaction zone A being above the highest temperature of the reaction gas mixture within reaction zone B.

Abstract: In a process for preparing a multiplephase multimetal oxide composition comprising Mo, V, Cu and, if desired, further elements, at least one phase is preformed separately and dispersed in a plastically deformable precursor composition of a further phase. The mixture is dried and calcined. The multimetal oxide composition is suitable as active composition of catalysts for the catalytically oxidation of organic compounds in the gas phase, in particular for the oxidation of acrolein to acrylic acid.