EP2321045A2 - Catalyseur destiné à l'oxydation en phase gazeuse d'hydrocarbures aromatiques les transformant en aldéhydes, acides carboxyliques et/ou anhydrides d'acides carboxyliques, notamment en anhydride d'acide phtalique, et procédé de production d'un catalyseur de ce type - Google Patents

Catalyseur destiné à l'oxydation en phase gazeuse d'hydrocarbures aromatiques les transformant en aldéhydes, acides carboxyliques et/ou anhydrides d'acides carboxyliques, notamment en anhydride d'acide phtalique, et procédé de production d'un catalyseur de ce type

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Publication number
EP2321045A2
EP2321045A2 EP09777410A EP09777410A EP2321045A2 EP 2321045 A2 EP2321045 A2 EP 2321045A2 EP 09777410 A EP09777410 A EP 09777410A EP 09777410 A EP09777410 A EP 09777410A EP 2321045 A2 EP2321045 A2 EP 2321045A2
Authority
EP
European Patent Office
Prior art keywords
catalyst
vanadium
oxide
silver
weight
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Application number
EP09777410A
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German (de)
English (en)
Inventor
Josef Breimair
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Stesatec GmbH
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Breimair Josef
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Filing date
Publication date
Application filed by Breimair Josef filed Critical Breimair Josef
Publication of EP2321045A2 publication Critical patent/EP2321045A2/fr
Withdrawn legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/66—Silver or gold
    • B01J23/68—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/002—Mixed oxides other than spinels, e.g. perovskite
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B01J21/063—Titanium; Oxides or hydroxides thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/20—Vanadium, niobium or tantalum
    • B01J23/22—Vanadium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/66—Silver or gold
    • B01J23/68—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/682—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with vanadium, niobium, tantalum or polonium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
    • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
    • B01J23/66—Silver or gold
    • B01J23/68—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J23/683—Silver or gold with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with chromium, molybdenum or tungsten
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/14—Phosphorus; Compounds thereof
    • B01J27/186—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J27/195—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with vanadium, niobium or tantalum
    • B01J27/198—Vanadium
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/14—Phosphorus; Compounds thereof
    • B01J27/186—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
    • B01J27/195—Phosphorus; Compounds thereof with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium with vanadium, niobium or tantalum
    • B01J27/198—Vanadium
    • B01J27/199—Vanadium with chromium, molybdenum, tungsten or polonium
    • B01J35/30—
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B01J37/0219—Coating the coating containing organic compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B01J37/0221—Coating of particles
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/02—Impregnation, coating or precipitation
    • B01J37/0215—Coating
    • B01J37/0228—Coating in several steps
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
    • C07B41/00—Formation or introduction of functional groups containing oxygen
    • C07B41/08—Formation or introduction of functional groups containing oxygen of carboxyl groups or salts, halides or anhydrides thereof
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
    • C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
    • C07C51/255—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting
    • C07C51/265—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of compounds containing six-membered aromatic rings without ring-splitting having alkyl side chains which are oxidised to carboxyl groups
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
    • C07D307/77—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom ortho- or peri-condensed with carbocyclic rings or ring systems
    • C07D307/87—Benzo [c] furans; Hydrogenated benzo [c] furans
    • C07D307/89—Benzo [c] furans; Hydrogenated benzo [c] furans with two oxygen atoms directly attached in positions 1 and 3
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
    • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2523/00—Constitutive chemical elements of heterogeneous catalysts
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08—Heat treatment

Definitions

  • Carboxylic anhydrides especially to phthalic anhydride
  • a molecular oxygen-containing gas for example air
  • the hydrocarbon to be oxidized for example o-xylene or naphthalene
  • the tubes filled with catalyst are surrounded by a heat transfer medium, for example a molten salt.
  • hot spots can occur in the catalyst bed, which can lead to undesirable effects, such as the total oxidation of the starting material or the formation of by-products which are difficult to separate, up to a limited throughput of starting material.
  • catalysts with different activity and chemical composition layer by layer in the reaction tubes to arrange in layers which according to the prior art usually the catalyst has the lowest activity in the region of the largest temperature maximum and the catalyst layers following in the direction of gas exit have an increased activity.
  • coated catalysts which generally consist of an inert, non-porous carrier material, on which at least one thin layer of the catalytically active material is applied in the form of a dish.
  • the composition of the catalytically active material plays a crucial role.
  • Such additives are, for example, cesium, antimony, phosphorus, boron, molybdenum, tungsten, tin, bismuth, silver, niobium, iron, potassium, rubidium, chromium and calcium.
  • multilayer catalysts which differ in activity and selectivity due to their different composition of active material
  • Catalyst bed several, different catalysts sequentially arranged in layers to perform different tasks depending on the location in the catalyst bed. This is essentially the requirement to control the exothermic reaction at high throughputs of starting material, while high selectivity and stability of the catalyst, safely.
  • EP A 21 325 describes catalysts for the preparation of phthalic anhydride whose active material comprises 60 to 99% by weight of titanium dioxide, 1 to 40% by weight of vanadium pentoxide and, based on the total amount of TiO 2 and V 2 O 5 up to 2% by weight Phosphorus and up to 1, 5 weight% rubidium and / or cesium, wherein the catalytically active material is applied in two layers on the support.
  • the inner layer contains 0 to 2.0% by weight of phosphorus and no rubidium and / or cesium
  • the outer layer contains 0 to 0.20% by weight of phosphorus and 0.02 to 1.5% by weight of rubidium and / or cesium
  • the catalytically active composition of these catalysts may contain, in addition to the constituents mentioned, further substances, for example up to 10% by weight of an oxide of the metals molybdenum, tungsten, niobium, tin, silicon, antimony, hafnium.
  • inert carrier material steatite is used as inert carrier material steatite is used.
  • EP A 286448 describes a process for the preparation of phthalic anhydride, in which two different catalysts are used with similar content of titanium dioxide and vanadium pentoxide. They differ essentially in that one catalyst additionally contains 2 to 5% by weight of a cesium compound, in particular cesium sulfate, but no phosphorus, tin, antimony, bismuth, tungsten or molybdenum compounds, and the second catalyst additionally contains 0, 1 to 3.0% by weight of a phosphorus, tin, antimony, bismuth, tungsten or molybdenum compound.
  • a cesium compound in particular cesium sulfate
  • the second catalyst additionally contains 0, 1 to 3.0% by weight of a phosphorus, tin, antimony, bismuth, tungsten or molybdenum compound.
  • US 4,864,036 relates to a catalyst for the production of phthalic anhydride, which is prepared in several steps.
  • a catalyst for the production of phthalic anhydride which is prepared in several steps.
  • a first step a catalyst for the production of phthalic anhydride, which is prepared in several steps.
  • a first step a catalyst for the production of phthalic anhydride, which is prepared in several steps.
  • Tungsten compound on titanium dioxide in the anatase modification and then calcined. Thereafter, in a second step, the calcined
  • GB 1140264 relates to an oxidation catalyst for aromatic and non-aromatic hydrocarbons to carboxylic acids, which consists of an inert, nonporous support and a 0.02 to 2 mm thick layer of active material, which in turn from 1 to 15% V 2 O 5 and 85 to 99 % Titanium dioxide, wherein the vanadium content of the total catalyst is in the range of 0.05 to 3%. It describes a catalyst in which the active material in addition to titanium dioxide and vanadium pentoxide additionally contains 0.1 to 3% by weight of at least one metal oxide from the group of silver, iron, cobalt, nickel, chromium, molybdenum or tungsten.
  • EP 0 447 267 describes a catalyst for the preparation of phthalic anhydride which comprises as catalytically active composition: (A) 1 to 20% by weight of V 2 O 5 and 99 to 80% by weight of a titanium dioxide in the anatase modification with a BET Surface of 10 to 60n ⁇ 7g and (B), based on 100 parts by weight of this mixture (A), 0.05 to 1, 2 parts by weight of at least one element from the group K, Cs, Rb and Tl as oxide and 0.05 to 2 parts by weight Silver, calculated as silver oxide.
  • EP 0522 871 B1 relates to a catalyst which, in addition to titanium dioxide and vanadium pentoxide, also contains 0.01 to 1% by weight of niobium as niobium pentoxide, 0.05 to 2% by weight of at least one element selected from potassium, cesium, rubidium or thallium as oxide, 0.2 to 1.2% by weight of phosphorus as P2O5, and 0.55 to 5.5% by weight of antimony oxide and 0.05 to 2% by weight of silver as Ag2O, using a pentavalent antimony compound as the source of the antimony becomes.
  • CN1108996 relates to a catalyst with two layers based on titanium dioxide / 2O5 which additionally contains at least one rare earth compound and at least one oxide of the elements antimony, phosphorus, zinc and silver, wherein the layer closer to the gas inlet additionally contains at least one alkali metal compound
  • Silver-vanadium oxide compounds with an atomic ratio Ag: V ⁇ 1 are known as silver bronzes.
  • the use of silver vanadium bronzes as the oxidation catalyst is well known in the literature.
  • WO 2005/092496 A1 describes a catalyst for the preparation of aldehydes, carboxylic acids and / or carboxylic anhydrides whose active composition comprises a phase A and a phase B in the form of three-dimensionally extended delimited regions, the phase A being a silver vanadium oxide bronze and Phase B is a mixed element oxide phase based on titania and vanadium pentoxide.
  • the molar ratio of Ag: V in phase A is 0.15 to 0.95.
  • the present invention is therefore based on the object to develop an improved catalyst for the gas phase oxidation of aromatic hydrocarbons to aldehydes, carboxylic acids and / or carboxylic anhydrides, in particular to phthalic anhydride, which results in high raw material throughput improved selectivity and long service life.
  • the technical and economic costs for the large-scale production of the catalyst should be kept as low as possible.
  • a catalyst for the catalytic gas phase oxidation of aromatic hydrocarbons to aldehydes, carboxylic acids and / or carboxylic anhydrides in particular to phthalic anhydride, claimed in which the active composition vanadium oxide, preferably vanadium pentoxide, titanium dioxide, preferably in the anatase modification, and at least one Mixed element oxide of silver with defined elements, preferably vanadium and / or molybdenum and / or tungsten and / or niobium and / or antimony, and / or a mixed element oxide of vanadium with defined elements, preferably bismuth and / or molybdenum and / or tungsten and / or Antimony and / or niobium.
  • mixed element oxides preferably of mixed metal oxides, of silver with, for example, vanadium, molybdenum, tungsten, niobium and / or antimony
  • mixed element oxides preferably of mixed metal oxides, of vanadium with, for example, bismuth, Molybdenum, tungsten, niobium and / or antimony, or their precursor compounds as a raw material source in the preparation of the catalyst suspension or in the preparation of a powder mixture used for the coating process and / or as part of the active material of the catalysts in addition to the components titanium dioxide and vanadium oxide
  • silver as a constituent of the active material has been described many times.
  • the catalyst suspension used in addition to silver oxide and corresponding salts such as silver nitrate, silver sulfate, silver halides, silver sulfide, silver phosphate, silver salts of organic acids, silver hydroxide, ammonium salts of silver and amine complexes of silver.
  • Most of these sources are mononuclear converted into silver oxide upon heating of the catalyst in the reactor and are thus present in the active mass as silver oxide, while, for example, silver phosphates and silver halides are present in the active mass unchanged and are not converted to silver oxide during the thermal treatment.
  • An essential aspect of the catalysts according to the invention is that conventional catalysts which contain at least titanium dioxide and vanadium oxide in the active composition contain as additional dopants mixed element oxides of silver with vanadium and / or other defined elements and / or mixed element oxides of vanadium with other defined elements at least one mixed element oxide of silver and / or vanadium and / or a corresponding precursor compound is added to at least one of these mixing element compounds in the preparation of the catalyst suspension or in the preparation of a powder mixture used for the coating of the carrier.
  • the invention also expressly also relates to a process for the preparation of the catalysts according to the invention just described, comprising preparing a catalyst suspension or a mixture of the various components containing at least titanium dioxide in the anatase modification and a vanadium compound and at least one mixed element oxide of the silver and / or Vanadiums with defined elements or a corresponding precursor compound contains at least one of these mixed element oxides as a raw material source.
  • All components are advantageously mixed together in an aqueous medium and then applied by a spray process (preferably fluidized bed or drum method) on a ceramic support.
  • the Mischelementoxidphase of silver and / or vanadium or their Mischelementoxid precursor compounds are advantageously added directly to the catalyst suspension with the main constituents of titanium dioxide and vanadium oxide and other promoters and are generally not spatially ⁇ separate phases to a phase consisting of titanium dioxide and vanadium oxide before.
  • all constituents of the catalyst suspension form a uniform phase which, in addition to the components titanium dioxide and vanadium oxide, also contains the relevant mixed element oxides and optionally further components.
  • the respective mixed element oxides may also be used alone or in combination with other compounds in one or more coating layers which do not contain titanium dioxide and / or vanadium oxide in the active composition.
  • catalysts or precursors for the production and preparation of catalysts for the gas phase partial oxidation of aromatic hydrocarbons can thus be realized with a gas containing molar oxygen, which are composed of an inert, non-porous support material and one or more layers (s) applied thereon, wherein at least one of these layers contains 0.01 to 15% by weight, based on the total weight of these layers, of one or more of the above-mentioned mixed element oxides or their precursor compounds.
  • a concrete process procedure for the production of carboxylic acids and / or carboxylic anhydrides by the partial oxidation of aromatic hydrocarbons in the gas phase with a molecular oxygen-containing gas at elevated temperature on a catalyst whose active mass is applied shell-shaped on an inert carrier claimed that characterized in that a shell catalyst whose catalytically active composition, based on their total weight, 0.01 to 15% by weight of a Mischelementoxids of silver with vanadium and / or a Mischelementoxids of silver with other defined elements and / or 0.01 to 10% by weight of a mixed element oxide of vanadium with bismuth and / or a Mixed element oxide of vanadium with other defined elements and simultaneously titanium dioxide in the anatase modification and a vanadium compound (preferably V2O5), wherein the mixed element oxide compound (s) or their precursor compound (s) already for the preparation of the catalyst suspension and / or the powder mixture, from which the active composition is formed after coating the support by thermal treatment is or will be used
  • At least one non-inventive coated catalyst the vanadium oxide in its active material as essential constituents, in particular
  • Hydrocarbons to carboxylic acids and / or carboxylic anhydrides or absent and be used in a combined bed (that is, in a single or multi-layered mixture) together with one or more of the inventive catalysts described above.
  • the gaseous stream is preferably passed over a bed of at least two layers of catalysts, wherein the catalyst located closer to the gas inlet contains a catalyst according to the invention and the bed of the downstream catalyst contains at least one catalyst whose catalytically active material comprises vanadium oxide and a titanium dioxide in the Anatase modification contains, but no mixed element oxide of the silver with elements such as vanadium, molybdenum, tungsten, niobium, antimony and / or no mixed element oxide of vanadium with elements such as bismuth, molybdenum, tungsten, niobium, antimony.
  • catalyst beds consisting of at least two layers may also be used, all catalyst layers containing catalysts according to the invention.
  • the catalysts used according to the invention can differ by the type and amount of the respective mixed element oxides in the active composition,
  • At least one part, particularly preferably all catalyst layers used in the catalyst bed, including the catalysts according to the invention having a catalytically active composition comprising 1 to 40% by weight of vanadium oxide (calculated as V 2 O 5 ), 50 to 99% by weight of titanium dioxide (calculated as TiO 2 ), up to 1% by weight of an alkali metal compound (preferably a cesium compound, calculated as alkali metal), up to 1.5% by weight of a phosphorus compound (calculated as P) and up to 10% by weight of an antimony compound (calculated as Sb 2 O 3 ).
  • a catalytically active composition comprising 1 to 40% by weight of vanadium oxide (calculated as V 2 O 5 ), 50 to 99% by weight of titanium dioxide (calculated as TiO 2 ), up to 1% by weight of an alkali metal compound (preferably a cesium compound, calculated as alkali metal), up to 1.5% by weight of a phosphorus compound (calculated as P) and up to 10% by weight of
  • the catalysts according to the invention preferably contain 0.01 to 15% by weight of at least one mixed element oxide of silver with at least one element from the group vanadium, niobium, tantalum, titanium, zirconium, chromium, molybdenum, tungsten, cerium, lanthanum, Aluminum, boron, manganese, iron, cobalt, nickel, copper, zinc, gold, cadmium, tin, lead, bismuth, antimony, arsenic, hafnium, rhenium, ruthenium, rhodium and palladium, and / or preferably 0.01 to 10 weight % of at least one mixed element oxide of vanadium with at least one of bismuth, antimony, niobium, tantalum, titanium, zirconium, chromium, molybdenum, tungsten, cerium, lanthanum, aluminum, boron, manganese, iron, cobalt, nickel, copper, Zinc
  • the content of mixed element oxides of silver with defined elements, in particular with, for example, vanadium and / or tungsten and / or molybdenum and / or niobium and / or antimony, in the active mass of catalysts in a preferred embodiment is in a range of 0.01 to 15% by weight, in a further preferred embodiment in a range of 0.01 to 10% by weight and in a particularly preferred embodiment in a range of 0.01 to 5% by weight.
  • the content of mixed element oxides of vanadium with defined elements is in the active mass of catalysts in a preferred embodiment in a range of 0.01 to 10% by weight and in a particularly preferred embodiment in a range of 0.01 to 5% by weight.
  • a catalyst according to the invention is used in a first catalyst layer located closest to the gas inlet, which is also the location with the highest hot spot. In the direction of gas outlet at least one further catalyst layer is connected, which generally has a higher activity than the first catalyst layer and which is generally a catalyst according to the prior art.
  • the catalyst according to the invention in this case contains at least one mixed element oxide of silver, preferably silver vanadate, and preferably a mixed element oxide of vanadium, preferably bismuth vanadate.
  • Gas inlet up to and including the location with the highest hot spot containing a catalyst according to the invention and for subsequent layers conventional, prior art catalysts are used and / or catalysts of the invention are used with a reduced content of the claimed mixed element oxides in the active material.
  • At least one of the catalyst layers located in front of the highest hotspot layer contains a mixed element oxide of silver, preferably a mixed element oxide of silver with molybdenum and / or tungsten, and more preferably a mixed element oxide of silver with vanadium the layer with the highest hot spot and the layers downstream therefrom do not contain mixed element oxide of the silver.
  • the layer with the highest hot spot advantageously contains a mixed element oxide of the vanadium with bismuth.
  • the catalyst layers following in the direction of the gas outlet of the hot spot catalyst layer preferably correspond to the prior art and generally do not contain catalysts according to the invention.
  • the compounds AgVOß and / or Ag 2 MoO 4 and / or Ag 2 WO 4 and / or BiVO 4 are used in the preparation of the catalyst suspension and / or are contained in the active material of the catalysts.
  • Mischelementoxiden of silver too small, comes the selectivity-enhancing effect not fully bear, while too much content of Mischelementoxiden of silver increased activity is observed, which leads to a reduced selectivity due to increased total oxidation to CO and CO 2 .
  • Too high a content of mixed element oxides of bismuth also has a negative effect on the selectivity of the catalyst and at the same time it can lead to an increased formation of by-products which cause a poorer color stability of the desired product phthalic anhydride.
  • too low a proportion of mixed element oxides of bismuth leads to no significant increase in the selectivity.
  • the catalyst activity gradually increases from the first catalyst layer used at the gas inlet to the last layer closest to the Gaustritt.
  • the activity adjustment can be carried out by various methods familiar to the person skilled in the art. For example, an increase in the catalyst activity in the layers from the gas inlet to the gas outlet by a gradual reduction of the alkali metal content in the active mass, an increase in the average BET surface area of the titanium dioxide used or an increase in the active material content of the total weight of the catalyst. A combination of different activity-setting measures can also be used.
  • the catalysts according to the invention advantageously comprise in the active composition at least one kind of titanium dioxide in the anatase modification, at least one compound of vanadium (preferably V2O5), at least one mixed element oxide of silver and / or vanadium and optionally a compound of the antimony, a compound of an alkali element and / or a phosphorus compound.
  • at least one kind of titanium dioxide in the anatase modification at least one compound of vanadium (preferably V2O5), at least one mixed element oxide of silver and / or vanadium and optionally a compound of the antimony, a compound of an alkali element and / or a phosphorus compound.
  • the total content of titanium dioxide is 50 to 99% by weight in the active composition of the catalysts according to the invention and particularly preferably 80 to 99% by weight.
  • the average BET surface area of the titanium dioxide of the catalysts according to the invention in the case of one or more titanium dioxide grades is advantageously 10-60 m 2 / g and particularly advantageously 12-30 m 2 / g, while the BET surface area of the individual grades is in the range of 3 to 300 m 2 / g.
  • the average BET surface area of the titanium dioxide used is calculated from the amount and BET surface area of the individual types used. At least one type of titanium dioxide whose mean particle size is in the range from 0.3 to 0.8 ⁇ m is preferably used.
  • the content of vanadium oxide in the active composition (calculated as V2O5) is in a preferred range of 1 to 40% by weight and in a particularly preferred embodiment in a range of 1 to 20% by weight.
  • the raw material sources vanadium pentoxide and / or vanadium oxalate are advantageously used.
  • other vanadium compounds are also suitable, such as, for example, ammonium metavanadate, polyvanadic acid, inter alia, or a mixture of various sources.
  • these precursor compounds or raw material sources of vanadium are converted into vanadium pentoxide in the thermal treatment of the catalyst or during heating of the catalyst in the reactor in the presence of molecular oxygen, so that the vanadium is present essentially in the pentavalent oxidation state in the active composition.
  • the active materials of these catalysts in addition to titanium dioxide, vanadium oxide, one or more mixed element oxides of silver and / or vanadium and additionally one or more elements from the group of alkali metals.
  • salts for example, sulfates, carbonates, nitrates, phosphates
  • Alkali metal compounds are used to control activity while improving the selectivity of the catalysts.
  • the alkali metal content in the active composition is in a range of 0 to 1.0% by weight, and more preferably in a range of 0 to 0.6% by weight.
  • a soluble cesium compound such as cesium sulfate is used to prepare the catalyst suspension.
  • the catalysts of the invention advantageously contain, in particular in the active mass of the hot spot catalyst layer, also an antimony compound as part of the active material for improving the thermal stability.
  • the content of antimony in the active composition is advantageously in a range of 0 to 10% by weight (calculated as Sb 2 O 3), and more preferably in a range of 0 to 5% by weight, depending on the position of the catalyst in the entire catalyst bed and depending on the thermal load of the respective catalyst in the respective position.
  • various antimony compounds for example antimony salts or antimony oxides, in various oxidation states.
  • antimony III oxide is used in the preparation of the catalyst suspension.
  • the catalysts according to the invention may contain a phosphorus compound in the catalytically active composition or it may be added a phosphorus compound as a raw material source in the preparation of the catalyst suspension or a powder mixture used for the coating of the carrier.
  • the phosphorus content of the active composition is in a range from 0 to 1.5% by weight (calculated as P).
  • the raw material source for the catalysts according to the invention is preferably ammonium dihydrogen phosphate.
  • At least one layer contains a catalyst according to the invention which contains at least one of the relevant mixed element oxides.
  • the first layer which is closest to the gas inlet and which is also the location with the highest hot spot, preferably contains a catalyst according to the invention.
  • a catalyst according to the invention it is advantageous if all the layers in the
  • Catalyst bed starting from the gas inlet up to and including the location with the highest hot spot catalysts according to the invention.
  • the nature of the mixed element oxides of, for example, silver can vary in the various layers concerned. It is advantageous, also the other compositions of the active material according to their position in the
  • the layer with the highest local temperature maximum contains a mixed element oxide of the silver and / or a mixed element oxide of the bismuth with vanadium.
  • Layers in one or more beds contains at least one catalyst layer which is located upstream of the hot spot catalyst layer, at least one Mixed element oxide of the silver with the specified elements, particularly advantageously with vanadium and / or molybdenum and / or tungsten.
  • At least one of the layers from the gas inlet to the layer with the highest hot spot contains a mixed element oxide of the silver, in particular a mixed element oxide of silver with vanadium and / or molybdenum and / or tungsten, while the layer with the highest hot Spot preferably contains a mixed element oxide of vanadium, in particular a mixed element oxide of vanadium with bismuth.
  • all layers from the gas inlet to the layer with the highest hot spot contain a mixed element oxide of silver and only the layer with the highest hot spot contains an additional mixed element oxide of vanadium with bismuth.
  • polynuclear mixed element oxides or their precursor compounds as a source in the preparation of the catalyst suspension or a powder mixture used for the coating of the support material.
  • mixed element oxides of silver can also be used to prepare the catalyst suspension and / or the active material which have a smaller or greater atomic ratio to the silver than is present in the case of AgVO 3.
  • the amount of mixed element oxide and / or precursor compounds in the catalyst suspension or powder coating mixture must be adjusted to provide an optimum level of silver in the active mass of the finished catalyst to obtain.
  • the described Mischelementoxidphase or its precursor compound is already formed before it is added to the catalyst suspension or the powder mixture used for the coating of the carrier.
  • one or more corresponding precursor compounds to the catalyst suspension or to the powder mixture, which are then converted to the corresponding mixed-element oxides during the thermal treatment of the catalyst.
  • mixed element oxides of silver present with other elements and / or their precursor compounds can be used not only in the integer molar ratio as raw material source in the production of the catalyst suspension or in the active composition of the inventive catalysts, but also two- or polynuclear mixed element oxides of Silver with a large atomic deficit or excess silver.
  • the content of the relevant mixed element oxide in the catalyst suspension and / or the active composition must then be increased or decreased.
  • the two or more nuclear mixed element oxides of silver are represented by the general formula
  • x more preferably has a value of 0.1 to 5
  • the value of the variable y is preferably 0 to 0.3.
  • n a number which is determined by the valence and frequency of the elements other than oxygen in the formula I
  • Precursor compounds of the respective mixed element oxides and / or their Starting compounds are used and the catalysts of the invention with the relevant Mischelementoxiden be formed only in the reactor by calcination at elevated temperature or during the heating of the catalyst in the reactor.
  • the use of the mixed element oxides AgVO3, Ag2MoO4, Ag2WO4 and / or mixed element oxides of these elements with other atomic ratios leads to an improvement of the catalysts
  • the compound AgVO3 as a constituent of the catalysts according to the invention, which is used as an additive in the preparation of the catalyst suspension or the active composition, wherein the active composition at least still titanium dioxide in the anatase modification and a vanadium compound contains.
  • the catalyst according to the invention preferably also comprises at least one compound of an element of the first main group.
  • the catalyst according to the invention also contains an antimony compound, in particular Sb 2 O 3 in the active composition and optionally a phosphorus compound
  • one or more or all of said catalyst layers from gas entrance to and including the highest hot spot layer has a mixed element oxide of silver with vanadium and / or tungsten and / or molybdenum of from 0.01% to 15% by weight, in particular from 0.01 to 10.0% by weight and more preferably from 0.01 to 5% by weight in the active composition.
  • the silver vanadium mixed element oxides are compounds having a molar ratio of Ag: V of 1: 1, in particular the mixed element oxide AgVO3. This is not a so-called silver vanadium bronze in which the atomic ratio of Ag: V is by definition less than 1: 1.
  • the use of bismuth vanadate as a source of raw material in the preparation of the catalyst suspension or as part of the active composition has led to an improvement in the selectivity. It is advantageous if the catalysts of the invention contain BiVO4 as a constituent of the active material, in particular in one or more layers from the gas inlet up to and including the layer with the highest hotspot.
  • the catalysts of the invention can in addition to titanium dioxide and
  • Vanadium oxide simultaneously at least one mixed element oxide of the silver with one or more of said elements and at least one mixed element oxide of the
  • Vanadiums containing one or more of the said elements are used to prepare the catalyst suspension of the catalysts according to the invention and / or are present side by side in the active mass of the catalysts.
  • the catalysts according to the invention additionally contain at least one alkali metal compound, preferably a cesium compound, an antimony compound, preferably antimony I-1 oxide and optionally a phosphorus compound.
  • Mischelementoxide of vanadium with other elements or their precursor compounds can not only be used in integer atomic ratio Mischelementoxide of vanadium with other elements or their precursor compounds as a source of raw material in the preparation of the catalyst suspension or present in the active material of the catalysts of the invention, but also two or more nuclear mixed element oxides of vanadium with a large atomic Deficit or excess of vanadium.
  • the content of the relevant mixed element oxide in the catalyst suspension and / or the active mass must then be increased or decreased.
  • the two or more nuclear mixed element oxides of vanadium are described by the following general formula according to claim 12:
  • so-called coated catalysts in which the catalytically active composition is cup-shaped in one or more layers to a support material which is generally inert under the reaction conditions, such as porcelain, magnesium oxide, tin dioxide, silicon carbide, cersilicate, magnesium silicate (steatite), zirconium silicate , Alumina, quartz, or mixtures of these carrier materials is applied.
  • a support material which is generally inert under the reaction conditions
  • carrier materials made of steatite or silicon carbide have proven successful in the art.
  • an aqueous solution and / or an organic solvent-containing solution or suspension (referred to herein as "catalyst suspension") of the active composition components and / or their precursor compounds is generally applied to the support material in the fluidized bed process (DE-A 2106796) at elevated temperature.
  • the coating of the inert, non-porous carrier material with the active ingredient components or their precursor compounds as a suspension or powder mixture can likewise be carried out in a heated coating drum at elevated temperatures.
  • the coating temperature is advantageously in a range of 50-450 0 C.
  • the binder used decomposed after filling the catalyst in the reactor usually when the reactor is heated to operating temperature or at the latest when commissioning the catalyst and completely removed from the catalyst.
  • the remaining on the inert support material as a thin shell catalytically active components are referred to as active mass.
  • the components of the active material may be partially derived from the components used in the catalyst suspension
  • Raw material sources or precursor compounds differ because some of them are chemically converted by the heat treatment of the catalyst and are usually converted into the corresponding metal oxides. It has now surprisingly been found that the performance of the catalysts depends not only on the composition and amount of the active material (after heating or annealing present catalytically active compounds) of the catalysts, but used in the catalyst suspension or for the coating of the carrier Powder mixed raw material sources have a significant influence on the selectivity, activity and service life of the catalysts.
  • the invention also relates to a process for the preparation of aldehydes, carboxylic acids and / or carboxylic acid anhydrides comprising contacting a gaseous stream containing an aromatic hydrocarbon and a gas containing molecular oxygen at an elevated temperature with a catalyst as defined above.
  • the mixed element oxides used as raw material source for the catalyst suspension can be prepared in various ways and be added to the catalyst suspension as an isolated compound or directly as a reaction mixture. Likewise, corresponding precursor compounds of the mixed metal oxides can be added to the catalyst suspension. These are advantageously polynuclear mixed element compounds or Mischmetalloxidtimen, which generally have a different crystal structure than the corresponding present in the active composition thermally treated Mischelementoxide and also may contain water of crystallization.
  • the reaction of a solution of a metal compound with a suspension of a metal oxide at elevated temperatures in an aqueous or nonaqueous solvent is also advantageously suitable for the preparation of the mixed element oxides and / or their precursor compounds used in the catalysts according to the invention.
  • a silver vanadium oxide used for the catalysts according to the invention can advantageously be prepared by reacting silver nitrate in aqueous solution at elevated temperatures with vanadium pentoxide in the corresponding desired atomic ratios.
  • the resulting reaction mixture with the mixed metal compound contained therein can be added directly to the catalyst suspension or the corresponding mixed metal compound but also previously isolated and optionally thermally treated.
  • polar organic solvents such as polyols, polyethers or amines can also be used as solvents.
  • a metal oxide or a plurality of metal oxides such as vanadium pentoxide and molybdenum trioxide
  • a silver compound and optionally another compound such as
  • Example, a phosphorus compound may be generally carried out at room temperature or elevated temperature.
  • the reaction is carried out at temperatures of 50 to 100 0 C and takes depending on the used
  • the mixed metal compound thus formed can be isolated from the reaction mixture and optionally stored until further use or as a suspension solution of the catalyst suspension, which still contains at least titanium dioxide and a vanadium compound added.
  • the mixed metal compound obtained and isolated by the reaction may also be subjected to thermal treatment at elevated temperatures prior to addition to the catalyst suspension to effect rearrangement of the crystal structure and removal of water of crystallization.
  • this can be done by filtering off the suspension and drying of the resulting solid, wherein the drying can be carried out by various methods.
  • the drying of the mixed metal suspension is carried out by spray drying or freeze drying.
  • the mixed metal compounds may also be produced by fusing together, for example, such that various finely mixed metal oxide powders are reacted in a solid state reaction at elevated temperatures of 400 to 800 ° C.
  • the components of the catalyst suspension are generally in the form of
  • Oxides and / or in the form of compounds for example salts, which convert to oxides upon heating in the presence of oxygen.
  • metal salts such as phosphates or halides of the Catalyst suspension are added, which are unchanged in the active material of the catalyst after a thermal treatment.
  • the preparation of the catalysts according to the invention is generally carried out via a precursor of the finished catalyst, which can be stored as such.
  • This is an inert ceramic support on which the raw materials used in the catalyst suspension are applied by means of a spraying process and are advantageously fixed using an organic binder.
  • the active catalyst is usually formed by thermal treatment of this precursor or already during the heating of the catalyst in the reactor.
  • the metal compounds used are usually converted into the corresponding metal oxides.
  • vanadium oxalate is decomposed and converted to V 2 O 5 .
  • other compounds contained in the catalyst suspension can be converted to their oxidic compounds upon heating of the catalyst.
  • the ammonium dihydrogen phosphate is converted to P 2 O 5 and is present as such in the active composition.
  • hydrous mixed metal oxides are prepared and used as a raw material source in the preparation of the catalyst suspension, it is generally assumed that they lose the water of crystallization during the thermal treatment of the catalyst and possibly change its crystal structure.
  • the conversion of the raw material sources used in the catalyst suspension is preferably carried out at temperatures of 200 to 500 0 C and more preferably in the range of 300 to 500 0 C.
  • the shape of the inert carrier material is not critically important for the performance of the catalysts of the invention, however, in the prior art, in particular spheres or rings have proven to be advantageous moldings.
  • the layer thickness of the active composition or the sum of the layer thicknesses of the shells which contain the active composition is generally 20-400 ⁇ m and varies depending on the position of the catalyst according to the invention in the catalyst bed. It has further been found, surprisingly, that a spatial separation of the various components of the catalyst suspension from the mixed metal oxides used is generally not necessary in order to obtain improved catalysts. All components used in the catalyst suspension are generally mixed or mixed with the corresponding mixed element oxides and the uniformly mixed suspension is applied to the inert support. However, catalysts are also conceivable in which variously composed catalyst suspensions are applied successively to the inert ceramic support, wherein at least one layer contains a catalyst according to the invention and thus an inventive improved catalyst is formed.
  • a non-inventive catalyst suspension containing at least titanium dioxide, a vanadium compound and advantageously also an alkali metal compound first isolated and optionally thermally treated and then the resulting powder is generally mixed again with a powder (advantageous in Water) previously obtained from a catalyst suspension consisting of at least titanium dioxide, a vanadium compound and at least one mixed metal oxide or its precursor compound.
  • This new catalyst suspension can be applied as a layer alone to an inert ceramic support or else used in combination with other coating layers according to the invention and / or not according to the invention.
  • the catalysts of the invention are generally used for the partial gas phase oxidation of aromatic hydrocarbons to aldehydes, carboxylic acids and / or carboxylic anhydrides. These catalysts are particularly suitable for the gas phase oxidation of o-xylene and / or naphthalene to phthalic anhydride with a molecular oxygen-containing gas.
  • the catalysts according to the invention can be used for this purpose in a catalyst bed alone or in combination with other, differently active catalysts, for example catalysts of the prior art (vanadium pentoxide / anatase base without Mischmetalloxidkomponente).
  • the different catalysts according to the invention and not according to the invention are generally used in separate catalyst beds, which are arranged in at least one catalyst bed.
  • the use of the catalysts according to the invention in the catalyst layers closest to the gas inlet up to the position with the highest hot spot is advantageous.
  • novel catalysts and / or their precursor catalysts according to the invention are introduced into the reaction tubes of a reactor in layers.
  • the various layers may in this case consist of catalysts according to the invention and not according to the invention.
  • reaction tubes are in this case thermostated from the outside, which is generally done by means of a salt melt, which flows around the pipes.
  • the actually active catalyst is formed from the precursor of the catalyst by burning out the organic binder and generally using the respective raw material sources used in the catalyst suspension convert the corresponding oxidic compounds.
  • their chemical composition and / or their crystalline structure may also change.
  • the reaction gas at temperatures of 250-550 ° C, especially at 330 to 500 0 C and at a Kochduck of generally 0.1 to 2.5 bar, preferably 0.3 to 1, 5 bar passed, the space velocity is generally 1000 to 5000 h (-1).
  • the reaction gas supplied to the catalyst is generally produced by mixing a molecular oxygen-containing gas, preferably air, which may contain, besides oxygen, still suitable reaction moderators and or diluents such as steam, nitrogen and / or carbon dioxide, with the aromatic hydrocarbon to be oxidized
  • a molecular oxygen-containing gas preferably air
  • the molecular oxygen-containing gas is generally 1 to 100% by volume and more preferably 10 to 30% by volume oxygen, 0 to 30% by volume steam, preferably 0 to 20% by volume water vapor and 0 to 50% by volume.
  • -% preferably 0 to 1 vol .-% carbon dioxide
  • the rest may contain nitrogen.
  • the gas containing molecular oxygen is generally mixed at 20 to 200 g per Nm 3, and more preferably at 60 to 120 g per Nm 3 of the aromatic hydrocarbon to be oxidized.
  • the aromatic hydrocarbon is first on a bed of the catalyst of the invention only partially converted to a reaction mixture of starting material, intermediates and end product and this mixture reacted with at least one further catalyst, which may also be according to the invention or may be a catalyst according to the prior art.
  • the reaction can also be carried out with more than one reactor, wherein each reactor can be thermostated individually at different reaction temperatures and contains at least one catalyst bed with at least one catalyst layer. It suffices for the process according to the invention in this case if at least one of these reactors has a layer with a catalyst according to the invention.
  • the partially reacted reaction gas after passing through one or more catalyst layers with catalyst according to the invention in addition to the desired product phthalic anhydride also contains a substantial amount of unreacted o-xyloxy and intermediates such as o-tolualdehyde and o-toluic acid and phthalide.
  • the product mixture is passed without further separation over at least one further catalyst layer, which differs in terms of their chemical composition and activity of the catalyst according to the invention to ensure complete conversion of the raw material or the oxidation of the suboxidation to phthalic anhydride.
  • Catalyst bed with the catalyst according to the invention conceivable before the reaction gas is fed to one or more further catalyst beds.
  • reaction mixture successively passes through several catalyst layers without separation of starting materials or intermediates, wherein at least one of these catalyst layers, preferably the position (s) closer to the gas inlet, contains a bed of a catalyst according to the invention.
  • the catalyst according to the invention is used together with at least one further or several catalyst layers, wherein at least one of the catalyst layers from the gas inlet up to and including the layer with the highest hot spot located catalyst layers according to the invention
  • Catalyst generally contains from 1 to 40% by weight of vanadium pentoxide, calculated as V2O5, 50 to 99% by weight of titanium dioxide, calculated as TiO2, up to 1% by weight of an alkali metal compound, calculated as alkali metal
  • the catalysts used in combination generally used in layers which are closer to the gas outlet and follow the position with the highest hot spot, are based mostly on non-inventive catalysts based on titanium dioxide / V205, but contain no mixed element oxides of silver and / or vanadium. However, it is also possible to use exclusively catalysts according to the invention in all layers. In this case, the catalysts generally differ in the type and amount of mixed metal oxides present in the active composition.
  • the catalysts of the prior art used in combination with the catalysts of the invention generally have a titanium dioxide content of 60-99% by weight, a vanadium oxide content of 1 to 40% by weight, an alkali metal content up to 1% by weight, a phosphorus content of up to 1.5% by weight and an antimony content of up to 10% by weight.
  • the active materials of the catalysts according to the invention and / or not according to the invention may contain small amounts of further oxidic compounds for activity and selectivity control.
  • the various components of the catalyst suspension are added successively as solutions and / or as a powder in deionized water, and the resulting suspension is advantageously stirred for at least 12 hours.
  • Titanium dioxide in the anatase modification, V2O5 or vanadyl oxalate, cesium sulfate, ammonium dihydrogen phosphate, antimony trioxide, bismuth vanadate and silver vanadate, silver molybdate, silver tungstate and / or other mixed metal oxides of silver and vanadium are advantageously used as raw material sources for the components contained in the catalyst according to the invention.
  • an organic binder in the form of an aqueous dispersion of a vinyl acetate copolymer is added to the aqueous catalyst suspension and the total of about 20 to 25% suspension is stirred for a further 30 minutes.
  • an appropriate amount of the aqueous suspension, which contains the active ingredients and / or their precursor compounds and the organic binder spray applied to the inert support (steatite rings with 7x7x4 mm or 8x6x5 mm dimension) until a certain amount of the adhesive-containing Suspension is applied to the rings, so that results after calcination, the active mass given in the examples.
  • the proportion of active material in each case refers to the proportion of the catalytically active composition in the total weight of the catalyst, including the support in the respective catalyst layer, determined after calcining at 400 ° C. for 4 h.
  • the stated content of phosphorus refers to the amount of a phosphorus compound added in the catalyst suspension preparation. It is known to those skilled in the art that the actual content of phosphorus in the active mass may vary depending on how heavily the TiO 2 used is contaminated with phosphorus compounds.
  • the relevant multilayer catalyst system is filled, wherein in the examples described in each case the R1 layer next to the gas inlet and the R4 layer or the R5 layer is closest to the gas outlet.
  • thermowell of 2mm with built-in tension element for temperature measurement.
  • 4 Nm 3 of air at a loading of about 30 to 70 g-xylene / Nm 3 air were passed through the reaction tube hourly from top to bottom at a salt bath temperature of 340-380 0 C.
  • the reaction gas leaving the reaction tube is passed through an oil-cooled condenser, in particular by the fact that most of the phthalic anhydride formed is only completely separated off and by-products such as benzoic acid, maleic anhydride and phthalide are only partially precipitated.
  • the separated in the condensers raw PSA is using hot oil melted, collected, weighed and then determined the content of phthalic anhydride by GC analysis.
  • the yield of solid PSA thus determined is referred to as the crude PSA yield, since the pure PSA is generally a product obtained after the thermal pretreatment and distillative work-up. This is also familiar to the person skilled in the art.
  • Example 1 (Comparative Example): Catalyst System A (4 layers)
  • This catalyst system is a multi-layer system with four different layers.
  • the individual beds of this comparative catalyst contain no mixed element oxide of the silver.
  • Example 2 (Inventive): Catalyst System B (4 layers)
  • Example 2 At a loading of 58 to 63 g of o-xylene per Nm 3 of air and a total air flow of 4.0 Nm 3 per hour and 346 to 352 ° C SBT the catalyst system B described in Example 2 was tested. In this case, an average raw PSA yield (based on 100% o-xylene purity) was achieved after the run-in phase of 114.0% by weight and the phthalide content in the crude PSA was 0.06% by weight.
  • Example 3 (according to the invention): Catalyst system C (4 layers)
  • Example 3 At a loading of 58 to 65 g of o-xylene per Nm 3 of air and a total air flow of 4.0 Nm 3 per hour and 346 to 347 ° C SBT the catalyst system C described in Example 3 was tested. In this case, an average raw PSA yield (based on 100% o-xylene purity) was achieved after the run-in phase of 115.3% by weight and the phthalide content in the crude PSA was 0.04% by weight.
  • Example 4 (Inventive): Catalyst System D (4 layers)
  • Example 4 At a loading of 57 to 69 g of o-xylene per Nm 3 of air and a total air flow of 4.0 Nm 3 per hour and 346 to 348 ° C SBT the catalyst system D described in Example 4 was tested. In this case, an average raw PSA yield (based on 100% o-xylene purity) was achieved after the run-in phase of 113.9% by weight, and the phthalide content in the crude PSA averaged 0.02% by weight.
  • Example 5 (according to the invention): Catalyst system E (4 layers)
  • Example 5 At a loading of 52 to 62 g of o-xylene per Nm 3 of air and a total air flow of 4.0 Nm 3 per hour and 347 to 348 0 C SBT the catalyst system E described in Example 5 was tested. In this case, an average raw PSA yield (based on 100% o-xylene purity) was achieved after the run-in of 114.2% by weight and the phthalide content in the crude PSA was on average 0.01% by weight.
  • Example 6 (Comparative Example): Catalyst System F (5 layers)
  • Example 6 At a loading of 58 to 61 o-xylene per Nm 3 of air and a total amount of air of 4 Nm 3 per hour and 350 to 354 ° C SBT, the catalyst system F described in Example 6 was tested. In this case, an average raw PSA yield (based on 100% o-xylene purity) of 113.1% by weight was achieved after the run-in phase and the phthalide content in the crude PSA was 0.01% by weight.
  • Example 6 (Inventive): Catalyst System G (5 layers)

Abstract

L'invention concerne un catalyseur destiné à l'oxydation en phase gazeuse d'hydrocarbures aromatiques les transformant en aldéhydes, acides carboxyliques et/ou anhydrides d'acides carboxyliques, notamment en anhydride d'acide phtalique, selon lequel la masse active comporte de l'oxyde de vanadium, de préférence du pentoxyde de vanadium, du dioxyde de titane, de préférence sous forme anatase, et au moins un oxyde mixte de l'argent à éléments définis, de préférence du vanadium et/ou du molybdène et/ou du tungstène et/ou du niobium et/ou de l'antimoine et/ou un oxyde mixte du vanadium à éléments définis, de préférence du bismuth et/ou du molybdène et/ou du tungstène et/ou de l'antimoine et/ou du niobium. Lors de la production du catalyseur, notamment lors de la production d'une suspension de catalyseur ou d'un mélange de poudres destiné au revêtement d'un support, on utilise comme source de matière première au moins un oxyde mixte de l'argent et/ou du vanadium et/ou au moins un composé précurseur, notamment au moins un composé précurseur polynucléaire, d'au moins un oxyde mixte de l'argent et/ou du vanadium.
EP09777410A 2008-08-29 2009-07-24 Catalyseur destiné à l'oxydation en phase gazeuse d'hydrocarbures aromatiques les transformant en aldéhydes, acides carboxyliques et/ou anhydrides d'acides carboxyliques, notamment en anhydride d'acide phtalique, et procédé de production d'un catalyseur de ce type Withdrawn EP2321045A2 (fr)

Applications Claiming Priority (2)

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DE102008044890.7A DE102008044890B4 (de) 2008-08-29 2008-08-29 Katalysator für die katalytische Gasphasenoxidation von aromatischen Kohlenwasserstoffen zu Aldehyden, Carbonsäuren und/oder Carbonsäureanhydriden, insbesondere zu Phthalsäureanhydrid, sowie Verfahren zur Herstellung eines solchen Katalysators
PCT/EP2009/005372 WO2010022830A2 (fr) 2008-08-29 2009-07-24 Catalyseur destiné à l'oxydation en phase gazeuse d'hydrocarbures aromatiques les transformant en aldéhydes, acides carboxyliques et/ou anhydrides d'acides carboxyliques, notamment en anhydride d'acide phtalique, et procédé de production d'un catalyseur de ce type

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EP2321045A2 true EP2321045A2 (fr) 2011-05-18

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EP09777410A Withdrawn EP2321045A2 (fr) 2008-08-29 2009-07-24 Catalyseur destiné à l'oxydation en phase gazeuse d'hydrocarbures aromatiques les transformant en aldéhydes, acides carboxyliques et/ou anhydrides d'acides carboxyliques, notamment en anhydride d'acide phtalique, et procédé de production d'un catalyseur de ce type

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EP (1) EP2321045A2 (fr)
KR (1) KR101706790B1 (fr)
CN (1) CN102196859B (fr)
BR (1) BRPI0913160B1 (fr)
DE (1) DE102008044890B4 (fr)
TW (1) TWI518079B (fr)
WO (1) WO2010022830A2 (fr)

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WO2011061132A1 (fr) * 2009-11-20 2011-05-26 Basf Se Catalyseur multicouche utilisé pour la production d'acides carboxyliques et/ou d'anhydrides d'acide carboxylique, à l'antimoniate de vanadium dans au moins une couche de catalyseur, et procédé de production d'anhydride d'acide phtalique à basse température en zone de surchauffe maximale
DE102013202048A1 (de) * 2013-02-07 2013-04-18 Basf Se Verfahren zur Herstellung einer katalytisch aktiven Masse, die ein Gemisch aus einem die Elemente Mo und V enthaltenden Multielementoxid und wenigstens einem Oxid des Molybdäns ist
EP3047904A1 (fr) 2015-01-22 2016-07-27 Basf Se Système catalyseur pour oxydation d'o-xylène et/ou de naphtalène pour produire de l'anhydride phtalique
CN107999107A (zh) * 2016-10-28 2018-05-08 中国石油化工股份有限公司 一种顺酐催化剂及其制备方法和应用
DE102017202351A1 (de) * 2017-02-14 2018-08-16 Clariant International Ltd Katalysatormaterial zur Oxidation von Kohlenwasserstoffen mit antimondotiertem Titandioxid
CN109110910A (zh) * 2018-08-31 2019-01-01 江苏新亿源环保科技有限公司 一种高催化性悬浮梯级生物滤料的制备方法
CN109158119A (zh) * 2018-09-14 2019-01-08 中海油天津化工研究设计院有限公司 一种用于均四甲苯氧化的催化剂及制备方法
CN109369544B (zh) * 2018-12-05 2022-06-03 兰州大学 一种催化氧化制备5-甲基吡嗪-2-羧酸的方法
CN114100651B (zh) * 2020-08-25 2023-12-08 中国石油化工股份有限公司 一种苯氧化制顺酐催化剂及其制备方法和应用
CN114539207B (zh) * 2020-11-24 2023-09-19 万华化学(四川)有限公司 一种制备丙交酯的方法及催化剂
CN114682278B (zh) * 2020-12-29 2023-09-01 中国石油化工股份有限公司 一种抗失磷钒磷氧催化剂
IT202100021746A1 (it) 2021-08-11 2023-02-11 Polynt S P A Letto catalitico multistrato per la produzione di anidride ftalica.

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WO2010022830A2 (fr) 2010-03-04
TW201012805A (en) 2010-04-01
DE102008044890B4 (de) 2023-09-14
CN102196859A (zh) 2011-09-21
CN102196859B (zh) 2014-08-06
KR20110050694A (ko) 2011-05-16
TWI518079B (zh) 2016-01-21
KR101706790B1 (ko) 2017-02-15
DE102008044890A1 (de) 2010-03-04
WO2010022830A3 (fr) 2010-05-20
BRPI0913160B1 (pt) 2018-03-27
BRPI0913160A2 (pt) 2016-07-26

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