An improved process can be used for the production of methacrylates, in particular methacrylic acid and/or methyl methacrylate (MMA). Specific embodiments of this process can be used for the safe and efficient production of these products from C-4-based raw materials, in particular those based on isobutylene or tert-butanol as raw materials. With this novel process, it is possible to operate such processes for a longer period of time without any safety or cleaning related shutdowns. This makes it possible to carry out such processes as simple, economic, and environmentally friendly as possible.

An improved process can be used for the production of methacrylates, in particular methacrylic acid and/or methyl methacrylate (MMA). Specific embodiments of this process can be used for the safe and efficient production of these products from C-4-based raw materials, in particular those based on isobutylene or tert-butanol as raw materials. With this novel process, it is possible to operate such processes for a longer period of time without any safety or cleaning related shutdowns. This makes it possible to carry out such processes as simple, economic, and environmentally friendly as possible.

The present invention relates to a process for recovering acrylic acid which is obtained by catalytic gas phase oxidation of propene, wherein, in an absorption stage (K2), the acrylic acid is absorbed from the reaction mixture (1) from the gas phase oxidation with a first solvent (3) and is drawn off for distillative purification, and a gas mixture from the absorption stage (K2) is passed onward to a condensation stage, wherein, in the condensation stage, the gas mixture is condensed, and a condensed phase of the gas mixture is drawn off as acid water (4) and is subjected to a phase separation operation in a phase separation vessel (B1), comprising the steps of a) feeding the aqueous phase (4*) of the acid water (4) drawn off from the condensation stage that has been obtained in the phase separation vessel (B1) to an extraction stage (K7) in which acrylic acid present in the acid water (4) is extracted with a second solvent (5), b) feeding the acrylic acid-comprising extract (6) to a stripping column (K8) in which the acrylic acid is removed from the second solvent (5) with cycle gas (8), wherein the second solvent (5) removed is fed back again after the acrylic acid has been stripped out in the extraction stage (K7), c) feeding the acrylic acid-laden cycle gas (9) to a stripping cycle gas scrubber (K5) in which the acrylic acid is removed from the cycle gas with the first solvent stream (10) fed to the stripping gas scrubber (K5) and transferred into the first solvent (3), and d) feeding a first portion of the acrylic acid-laden first solvent (3) back to the absorption stage (K2).

The present invention further relates to a corresponding plant for recovery of acrylic acid.

The present invention relates to a process for recovering acrylic acid which is obtained by catalytic gas phase oxidation of propene, wherein, in an absorption stage (K2), the acrylic acid is absorbed from the reaction mixture (1) from the gas phase oxidation with a first solvent (3) and is drawn off for distillative purification, and a gas mixture from the absorption stage (K2) is passed onward to a condensation stage, wherein, in the condensation stage, the gas mixture is condensed, and a condensed phase of the gas mixture is drawn off as acid water (4) and is subjected to a phase separation operation in a phase separation vessel (B1), comprising the steps of a) feeding the aqueous phase (4*) of the acid water (4) drawn off from the condensation stage that has been obtained in the phase separation vessel (B1) to an extraction stage (K7) in which acrylic acid present in the acid water (4) is extracted with a second solvent (5), b) feeding the acrylic acid-comprising extract (6) to a stripping column (K8) in which the acrylic acid is removed from the second solvent (5) with cycle gas (8), wherein the second solvent (5) removed is fed back again after the acrylic acid has been stripped out in the extraction stage (K7), c) feeding the acrylic acid-laden cycle gas (9) to a stripping cycle gas scrubber (K5) in which the acrylic acid is removed from the cycle gas with the first solvent stream (10) fed to the stripping gas scrubber (K5) and transferred into the first solvent (3), and d) feeding a first portion of the acrylic acid-laden first solvent (3) back to the absorption stage (K2).

The present invention further relates to a corresponding plant for recovery of acrylic acid.

A process for producing a catalytically active multielement oxide comprising the elements Mo, W, V and Cu, wherein at least one source of the elemental constituents W of the multielement oxide is used to produce an aqueous solution, the resultant aqueous solution is admixed with sources of the elemental constituents Mo and V of the multielement oxide, drying of the resultant aqueous solution produces a powder P, the resultant powder P is optionally used to produce geometric shaped precursor bodies, and the powder P is or the geometric shaped precursor bodies are subjected to thermal treatment to form the catalytically active composition, wherein the aqueous solution used for drying comprises from 1.6% to 5.0% by weight of W and from 7.2% to 26.0% by weight of Mo, based in each case on the total amount of aqueous solution.

A process for producing a catalytically active multielement oxide comprising the elements Mo, W, V and Cu, wherein at least one source of the elemental constituents W of the multielement oxide is used to produce an aqueous solution, the resultant aqueous solution is admixed with sources of the elemental constituents Mo and V of the multielement oxide, drying of the resultant aqueous solution produces a powder P, the resultant powder P is optionally used to produce geometric shaped precursor bodies, and the powder P is or the geometric shaped precursor bodies are subjected to thermal treatment to form the catalytically active composition, wherein the aqueous solution used for drying comprises from 1.6% to 5.0% by weight of W and from 7.2% to 26.0% by weight of Mo, based in each case on the total amount of aqueous solution.

A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising rubidium, bismuth, cerium, molybdenum, iron and other promoters, with a desirable composition.

A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising rubidium, bismuth, cerium, molybdenum, iron and other promoters, with a desirable composition.

The invention relates to a process of the oxidative dehydrogenation of an alkane containing 2 to 6 carbon atoms and/or the oxidation of an alkene containing 2 to 6 carbon atoms, wherein the alkane and/or alkene is contacted with oxygen in the presence of a catalyst comprising a mixed metal oxide and one or more diluents selected from the group consisting of carbon dioxide, carbon monoxide and steam, and wherein the conversion of the alkane and/or alkene is at least 40%.

The invention relates to a process of the oxidative dehydrogenation of an alkane containing 2 to 6 carbon atoms and/or the oxidation of an alkene containing 2 to 6 carbon atoms, wherein the alkane and/or alkene is contacted with oxygen in the presence of a catalyst comprising a mixed metal oxide and one or more diluents selected from the group consisting of carbon dioxide, carbon monoxide and steam, and wherein the conversion of the alkane and/or alkene is at least 40%.