Abstract: The present invention relates to a process for preparing acrylic acid by two-stage heterogeneously catalyzed partial gas phase oxidation of propylene, in which the propylene source used is a preceding propane dehydrogenation and in which the first oxidation stage is operated with restricted propylene conversion, and unconverted propane and propylene present in the product gas mixture of the second partial oxidation stage are recycled substantially into the preceding propane dehydrogenation.

Abstract: A process for preparing at least one partial oxidation and/or ammoxidation product of a hydrocarbon by partially dehydrogenating at least one saturated hydrocarbon H under heterogeneous catalysis and using the resulting product gas mixture A, which comprises the partially dehydrogenated hydrocarbon H, as such or in modified form for heterogeneously catalyzed partial oxidation and/or ammoxidation of the partially dehydrogenated hydrocarbon present in the product gas mixture A, said process including at least one mechanical separating operation inserted between the product gas mixture A and the heterogeneously catalyzed partial oxidation and/or ammoxidation.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for heterogeneously catalyzed partial dehydrogenation of a hydrocarbon, in which a reaction gas mixture input stream comprising the hydrocarbon to be dehydrogenated is conducted through a fixed catalyst bed disposed in a shaft and the reaction gas mixture input stream is obtained in the shaft by metering an input gas II comprising molecular oxygen upstream of the fixed catalyst bed into an input gas stream I which comprises molecular hydrogen and the hydrocarbon to be dehydrogenated and is flowing within the shaft toward the fixed catalyst bed.

Abstract: A process for continuously producing water-absorbing polymer particles, wherein the monomer stems from at least two different sources and the monomer from one source differs from the monomer from at least one other source in the content of at least one secondary component.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a steel with specific elemental composition on its side in contact with the reaction gas, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a steel with specific elemental composition on its side in contact with the reaction gas, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: Processes comprising: (a) providing a reactant comprising a component selected from the group consisting of o-xylene, naphthalene and mixtures thereof, and a gas comprising oxygen; (b) reacting the reactant and the gas in a reaction system, in the presence of a catalyst, to form phthalic anhydride; wherein the reaction system comprises: (i) at least two reaction zones, each reaction zone cooled with a coolant; and (ii) an intermediate cooling zone disposed between a first of the at least two reaction zones and a second of the at least two reaction zones; and wherein the coolant entering the first of the at least two reaction zones has a temperature which is more than 20° C. higher than a temperature of the coolant entering the second of the at leas two reaction zones.

Abstract: A process for preparing at least one target product by partial oxidation and/or ammoxidation of propylene, in which the propylene source used is a propane dehydrogenation, the propane used therein being obtained by a rectificative prepurification of crude propane.

Abstract: Processes comprising: (a) providing a reactant comprising a component selected from the group consisting of o-xylene, naphthalene and mixtures thereof, and a gas comprising oxygen; (b) reacting the reactant and the gas in a reaction system, in the presence of a catalyst, to form phthalic anhydride; wherein the reaction system comprises: (i) at least two reaction zones, each reaction zone cooled with a coolant; and (ii) an intermediate cooling zone disposed between a first of the at least two reaction zones and a second of the at least two reaction zones; and wherein the coolant entering the first of the at least two reaction zones has a temperature which is more than 20° C. higher than a temperature of the coolant entering the second of the at leas two reaction zones.

Abstract: A method for the safe operation of a continuously operated heterogeneously catalyzed gas-phase partial oxidation of an organic compound in a reactor, the composition of the feed gas mixture being controlled by pressure-controlled concentration determination of relevant constituents.

Abstract: A reactor is proposed for partial oxidations of a fluid reaction mixture in the presence of a heterogeneous particulate catalyst, comprising one or more cuboidal thermoplate modules (1) which are each formed from two or more rectangular thermoplates (2) arranged parallel to each other while in each case leaving a gap (3) which can be filled with the heterogeneous particulate catalyst and is flowed through by the fluid reaction mixture; the heat of reaction being absorbed by a heat carrier which flows through the thermoplates (2) and thus at least partly evaporates, and also having a predominantly cylindrical shell (4, 15, 16) which releases the pressure at the thermoplate modules, completely surrounds them and comprises a cylinder jacket (4) and hoods (15, 16) which seal it at both ends and whose longitudinal axis is aligned parallel to the plane of the thermoplates (2), and also having one or more sealing elements (7, 23) which are arranged in such a way that the fluid reaction mixture, apart from flowing

Abstract: A process for preparing acrolein or acrylic acid or a mixture thereof from propane, in which the propane is initially dehydrogenated under heterogeneous catalysis to give propene, secondary components are removed and the remaining gas mixture, comprising propane and propene, is subjected to the heterogeneously catalyzed partial oxidation to acrolein or acrylic acid or a mixture thereof as the target product, target product is removed from the product gas mixture and the remaining residual gas, comprising excess oxygen and unconverted propane, is recycled into the propane dehydrogenation in such a way that the other propane fed to the dehydrogenation is at least partly converted under dehydrogenating conditions at the recycle point.

Abstract: A process for heterogeneously catalyzed partial dehydrogenation of a hydrocarbon, in which a reaction gas mixture input stream comprising the hydrocarbon to be dehydrogenated is conducted through a fixed catalyst bed disposed in a shaft and the reaction gas mixture input stream is obtained in the shaft by metering an input gas II comprising molecular oxygen upstream of the fixed catalyst bed into an input gas stream I which comprises molecular hydrogen and the hydrocarbon to be dehydrogenated and is flowing within the shaft toward the fixed catalyst bed.

Abstract: In a process for preparing at least one partial oxidation and/or ammoxidation product of propylene, the propylene is obtained from crude propane by dehydrogenating and subjected in the presence of unconverted propane as a constituent of a gas mixture 2 which comprises a total C4-hydrocarbon content of ?3% by volume to a heterogeneously catalyzed gas phase partial oxidation and/or partial gas phase ammoxidation.

Abstract: Acrolein and/or acrylic acid are prepared from propane and/or propene by a process comprising the following steps: (a) separation of propane and/or propene from a propane- and/or propene-containing gas mixture by absorption in an absorbent, (b) separation of the propane and/or propene from the absorbent to give a gas B and (c) use of the gas B obtained in stage (b) for an oxidation of propane and/or propene to acrolein and/or acrylic acid, no heterogeneously catalyzed dehydrogenation of propane without supply of oxygen being carried out between steps (b) and (c).

Abstract: A process for continuous heterogeneously catalyzed partial dehydrogenation of at least one hydrocarbon to be dehydrogenated in a reactor which is manufactured from a composite material which consists, on its side in contact with the reaction chamber, of a steel B with specific elemental composition which, on its side facing away from the reaction chamber, either directly or via an intermediate layer of copper, or of nickel, or of copper and nickel, is plated onto a steel A with specific elemental composition, and also partial oxidations of the dehydrogenated hydrocarbon and the reactor itself.

Abstract: A process is proposed for partial oxidation oxidation in the gas phase of C3 and/or C4 precursor compounds to (meth)acrolein and/or (meth)acrylic acid in the presence of a heterogeneous particulate catalyst in a reactor having one or more cuboidal thermoplate modules (1) which are each formed from two or more rectangular thermoplates (2) arranged parallel to each other while in each case leaving a gap (3) which can be filled with the heterogeneous particulate catalyst and is flowed through by the fluid reaction mixture; the heat of reaction being absorbed by a heat carrier which flows through the thermoplates (2) and thus at least partly evaporating, and also having a predominantly cylindrical shell (4, 15, 16) which releases the pressure at the thermoplate modules, completely surrounds them and comprises a cylinder jacket (4) and hoods (15, 16) which seal it at both ends and whose longitudinal axis is aligned parallel to the plane of the thermoplates (2), and also having one or more sealing elements (7, 2

Abstract: A process for the continuous gas-phase oxidation of C3- and C4-precursors to (meth)acrolein and/or (meth)acrylic acid in the presence of a catalyst in a reactor which has a feed for the reaction mixture at one reactor end and removal of the reaction mixture at the opposite reactor end and which is equipped with means, arranged in the interior of the reactor, for removing the heat of reaction, through which means a heat exchange composition flows and which means are in the form of heat exchanger plates, is proposed.