Abstract: The invention relates to a method for the heterogenically catalysed 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: A catalyst suitable for the gas-phase oxidation of organic compounds to &agr;,&bgr;-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: 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: The invention relates to a method for producing a multiple-phase multi-metal oxide material that contains Mo, V, Cu and, optionally, other elements. According to the invention, at least one phase is separately pre-formed and is dispersed in a plastically deformable precursor material of another phase. The mixture is then dried and calcined. The multi-metal oxide material is suited for use as an active material of catalysts for catalytically oxidizing organic compounds in the gas phase, in particular, for oxidizing acrolein into acrylic acid.

Abstract: In a process for heterogeneously catalyzed gas-phase oxidation, a reaction gas starting mixture comprising propane, molecular oxygen and, if desired, inert gas is passed at from 300 to 500° C. over a fixed-bed catalyst.

Abstract: A process for the catalytic gas-phase oxidation of propene to acrylic acid, in which the reaction gas starting mixture is oxidized, with an increased propene loading, in a first reaction stage, over a first fixed-bed catalyst and then the acrolein-containing product gas mixture of the first reaction stage is oxidized, in a second reaction stage, with an increased acrolein loading, over a second fixed-bed catalyst, the catalyst moldings in both reaction stages having an annular geometry.

Abstract: In a coated catalyst having a core and at least one shell surrounding the core, the core is made up of an inert support material, the shell or shells is/are made up of a porous support substance, with the shell being attached physically to the core, and a catalytically active metal selected from the group consisting of the metals of the 10th and 11th groups of the Periodic Table of the Elements is present in finely divided form or a precursor of the catalytically active metal is present in uniformly distributed form in the shell or shells.

Abstract: In a process for the preparation of acrolein and/or acrylic acid from propane, the propane is subjected, in a first reaction stage, to a partial oxydehydrogenation with molecular oxygen under homogeneous and/or heterogeneous catalysis to give propene and the product gas mixture formed in the first reaction stage is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propene oxidation.

Abstract: In a process for the preparation of acrolein and/or acrylic acid from propane, the propane is subjected, in a first reaction stage, to an oxydehydrogenation with molecular oxygen under homogeneous and/or heterogeneous catalysis to give propene and the product gas mixture formed in the first reaction stage is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propene oxidation.

Abstract: In a process for the preparation of acrolein by gas-phase partial oxidation under heterogeneous catalysis, a reaction gas starting mixture which contains propene and molecular oxygen in a molar C3H6:O2 ratio of >1 is reacted in reaction zones connected in series, at elevated temperatures, over solid-state catalysts, further molecular oxygen being added to the reaction gas mixture in the course of the partial oxidation.

Abstract: In a process for the catalytic gas-phase oxidation of acrolein to acrylic acid, the reaction gas starting mixture is passed, with an acrolein loading of ≧150 l (s.t.p.)/l.h, over a fixed-bed catalyst which is housed in two spatially successive reaction zones A, B, the reaction zone B being kept at a higher temperature than the reaction zone A.

Abstract: In a process for the catalytic gas-phase oxidation of propene to acrolein, the reaction gas starting mixture is passed with a propene loading of ≧160 l(S.T.P.)/l·h over a fixed-bed catalyst which is housed in two spatially successive reaction zones A,B, the reaction zone B being kept at a higher temperature than the reaction zone A.

Abstract: In a process for the preparation of acrolein and/or acrylic acid from propane, the propane is subjected, in a first reaction stage, to a partial oxydehydrogenation with molecular oxygen under homogeneous and/or heterogeneous catalysis to give propene and the product gas mixture formed in the first reaction stage is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propene oxidation.

Abstract: The multimetal oxide materials essentially consisting of Mo12BiaX1bFecX2dX3eOy  (I) where: X1 is Co and/or Ni, X2 is Si and/or Al, X3 is an alkali metal, 0.3≦a≦1, 2≦b≦10, 0.5≦c≦10, 0≦d≦10, 0≦e≦0.5 and y is the absolute value of the number which, assuming charge neutrality, is obtained from the sum of the valences and the stoichiometric coefficients of the other elements, the crystalline fractions containing, in addition to &bgr;-X1MoO4 as the main component, Fe2(MoO4)3 as a secondary component and no MoO3.

Abstract: In a process for preparing phthalic anhydride by catalytic gas-phase oxidation of o-xylene/naphthalene mixtures by molecular oxygen, use is made of a catalyst I in a first zone on the gas inlet side which makes up from 25 to 75 percent by volume of the total catalyst volume, comprising, in each case based on the catalytically active composition, from 1 to 10% by weight of vanadium oxide (calculated as V205), from 1 to 10% by weight of antimony oxide (calculated as Sb203) and from 80 to 98% by weight of titanium dioxide of the anatase type having a BET surface area of from 13 to 28 m2/g and also from 0.