Abstract: A process for the hydrothermal preparation of Mo- and V-comprising multimetal oxide materials, substantially exclusively sources from the group consisting of oxides, hydrated oxides, oxygen acids and hydroxides being used as sources of the elemental constituents of the multimetal oxide material, and a portion of the sources comprising the elemental constituent contained with an oxidation number which is below its maximum oxidation number.

Abstract: A process for preparing (meth)acrylic acid by conducting a saturated hydrocarbon precursor compound through a catalyst bed I whose catalysts I have, as the active composition, a multimetal oxide I which has a specific X-ray diffractogram and contains the elements Mo and V, at least one of the elements Te and Sb, and also at least one of the elements from the group consisting of Nb, Ta, W, Ce and Ti, wherein the catalyst bed I is interrupted by at least one catalyst bed II whose catalysts II have, as the active composition, a multimetal oxide II which contains the elements Mo, Bi and Fe.

Abstract: A process for preparing (meth)acrylic acid, in which a saturated hydrocarbon precursor compound is conducted through a catalyst charge which consists of two spatially successive catalyst beds I, II in the flow direction of the reaction mixture, each of which contains different catalysts and has different reaction-selectivity behavior.

Abstract: The invention relates to a method for producing acrylic acid by the heterogeneously catalysed gas-phase oxidation of propane on a multi-metal oxide mass, said mass containing the elements Mo, V, Te and/or Sb and having a specific X-ray diffractogram.

Abstract: A process for preparing (meth)acrylic acid by heterogeneously catalyzed gas phase partial oxidation of a saturated hydrocarbon precursor compound, in which the charging gas mixture contains from 5 to 25% by volume of steam and the molar ratio of molecular oxygen present in the charging gas mixture to saturated hydrocarbon precursor compound present in the charging gas mixture is from 1.5:1 to 2.5:1.

Abstract: Acrylic acid is prepared by heterogeneously catalyzed partial oxidation of propane by a process in which the steam content of the reaction gas starting mixture is reduced in the course of the process.

Abstract: Multimetal oxide materials which contain Mo and V and, if required, one or more of the elements from the group consisting of lanthanides, transition elements of the Periodic Table of the Elements and elements of the third to sixth main group of the Periodic Table of the Elements and which are prepared in the presence of an alkali metal other than Li and have the i-phase structure are used as active material in catalysts for partial gas-phase oxidations.

Abstract: A process for heterogeneously catalyzed partial direct oxidation of propane and/or isobutane, in which target product is removed in a workup stage from the product gas mixture obtained in the reaction stage, the remaining residual product gas mixture is divided into two portions of the same composition, one portion is recycled into the reaction stage and the other portion is discharged, and both the reaction stage and the workup stage are operated at elevated pressure.

Abstract: The invention relates to a process for preparing unsaturated nitrites from the corresponding alkanes which comprises the steps:

Abstract: In a process for the preparation of acrolein or acrylic acid or a mixture thereof from propane, the propane is subjected, in a first reaction stage, to a partial dehydrogenation under heterogeneous catalysis to give propene, of the components contained in the product gas mixture formed in the first reaction stage other than propene and propane at least a portion of the molecular hydrogen present is then separated off from said mixture and the product gas mixture is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propylene oxidation, molecular nitrogen being present for diluting the reaction gas mixture during the propylene oxidation.

Abstract: A process for preparing a multimetal oxide composition comprising one of the elements Mo and V and at least one of the elements Te and Sb, in which part solutions which each contain partial amounts of the required starting compounds of the elemental constituents present in the multimetal oxide composition in dissolved form are prepared from the starting compounds, these part solution streams are combined and mixed and the resulting mix solution stream is broken up into fine droplets, dried by means of a hot gas and the solid obtained is treated thermally at elevated temperature.

Abstract: Acrylic acid is prepared by heterogeneously catalyzed partial oxidation of propane by a process in which the steam content of the reaction gas starting mixture is reduced in the course of the process.

Abstract: The invention relates to a shell catalyst whose active material shell is a multimetal oxide that contains the elements Mo, V and Te and/or Sb. The invention further relates to the use of said shell catalyst for gas-phase catalytic oxidation of propane to acrylic acid.

Abstract: A process for preparing a multimetal oxide material which contains the elements Mo, V and Te and/or Sb and at least one of the elements Nb, Ti, W, Ta and Ce and if desired promoters and has a specific X-ray diffraction pattern, in which process the last process step comprises washing with acidic liquids. In addition, a multimetal oxide material obtainable in such a way is used as a catalyst for heterogeneously catalyzed gas-phase partial oxidations and/or ammoxidation of hydrocarbons.

Abstract: A process for the preparation of acrylic acid or methacrylic acid is described, in which propane or isobutane is reacted with molecular oxygen in the gas phase in a fluidized-bed reactor containing a catalyst, the catalyst containing a multimetal oxide comprising molybdenum, tellurium and/or antimony, vanadium and niobium, and a catalyst activator which comprises at least one tellurium compound being added to the reactor during the reaction.

Abstract: A multimetal oxide material contains the elements Mo, V and Te and/or Sb and at least one of the elements Nb, Ti, W, Ta and Ce and promoters and has a specific X-ray diffraction pattern. Moreover, such a multimetal oxide material is used as a catalyst for heterogeneously catalyzed gas-phase partial oxidations of hydrocarbons.

Abstract: In a process for the preparation of acrylic acid by heterogeneously catalyzed gas-phase oxidation of propene with molecular oxygen in a reaction zone, the catalytically active material is a multimetal oxide which contains the elements Mo, V, Te and/or Sb and has a specific structure.

Abstract: A process for the heterogeneously catalyzed gas-phase partial oxidation of acrolein to acrylic acid over a multimetal oxide material having a specific structure, which contains the elements Mo and V, at least one of the elements Te and Sb and at least one of the elements from the group consisting of Nb, Ta, W and Ti and is doped with promoter elements, is described.

Abstract: The invention relates to a method for producing acrylic acid by the heterogeneously catalysed gas-phase oxidation of propane on a multi-metal oxide mass, said mass containing the elements Mo, V, Te and/or Sb and having a specific X-ray diffractogram.

Abstract: In a process for the preparation of acrolein or acrylic acid or a mixture thereof from propane, the propane is subjected, in a first reaction stage, to a partial dehydrogenation under heterogeneous catalysis to give propene, of the components contained in the product gas mixture formed in the first reaction stage other than propene and propane at least a portion of the molecular hydrogen present is then separated off from said mixture and the product gas mixture is then used for the preparation of acrolein and/or acrylic acid by gas-phase catalytic propylene oxidation, molecular nitrogen being present for diluting the reaction gas mixture during the propylene oxidation.