Classifications

• • 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
  • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
  • B01J21/04—Alumina
• • 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
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/46—Ruthenium, rhodium, osmium or iridium
• • 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
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/46—Ruthenium, rhodium, osmium or iridium
  • B01J23/462—Ruthenium
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B7/00—Halogens; Halogen acids
  • C01B7/01—Chlorine; Hydrogen chloride
  • C01B7/03—Preparation from chlorides
  • C01B7/04—Preparation of chlorine from hydrogen chloride
• • 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
  • B01J23/48—Silver or gold
  • B01J23/52—Gold
• • 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
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/72—Copper
• • 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
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/89—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper combined with noble metals
  • B01J23/8926—Copper and noble metals

Definitions

• the invention relates to a mechanically stable catalyst based on alpha-alumina as a carrier.
• the invention further relates to such a catalyst for the catalytic oxidation of hydrogen chloride with oxygen to chlorine and a method for the catalytic oxidation of hydrogen chloride using the catalyst.
• EP-A 0 743 277 discloses a process for the preparation of chlorine by catalytic hydrogen chloride oxidation, in which a ruthenium-containing supported catalyst is used. Ruthenium is applied to the support in the form of ruthenium chloride, ruthenium oxychlorides, chloro-ruthenate complexes, ruthenium hydroxide, ruthenium-amine complexes or in the form of further ruthenium complexes.
• the catalyst may contain as further metals palladium, copper, chromium, vanadium, manganese, alkali, alkaline earth and rare earth metals.
• ruthenium (III) chloride on alumina is used as catalyst in a process of catalytic hydrogen chloride oxidation.
• gamma-alumina is used as the alumina carrier.
• the object of the present invention is to improve the mechanical strength of alumina carriers. It is still the task, catalysts with increased mechanical To provide strength for gas phase reactions, in particular for the catalytic hydrogen chloride oxidation.
• the object is achieved by a catalyst for gas-phase reactions with high mechanical stability, containing one or more active metals on a support containing alumina as support material, characterized in that the alumina content of the support consists essentially of alpha-alumina.
• the carrier used according to the invention may contain alpha-alumina in admixture with other carrier materials.
• Suitable further support materials are, for example, graphite, silicon dioxide, titanium dioxide and zirconium dioxide, preferably titanium dioxide and zirconium oxide, for example in amounts of up to 50% by weight.
• the carrier consists essentially of alumina, for example at 90 wt .-% and above, more preferably it consists of at least 96 wt .-% of alumina.
• the alumina content of the carrier consists essentially of alpha-alumina, preferably it consists of at least 90 wt .-%, more preferably at least 98 wt .-% of alpha alumina, based on the total alumina content of the carrier.
• the phase composition of the carrier can be determined by XRD (X-Ray Diffraction).
• the catalyst according to the invention is used for carrying out gas-phase reactions at a temperature of above 200.degree. C., preferably above 320.degree. C., more preferably above 350.degree.
• the reaction temperature is generally not more than 600.degree. C., preferably not more than 500.degree.
• the catalyst of the invention may contain any active metals and other metals as promoters. These are usually in amounts up to 10 wt .-%, based on the weight of the catalyst, in the catalyst. SoII the catalyst according to the invention in the catalytic hydrogen chloride oxidation (Deacon process) are used, the active metals are selected from the elements of the groups 7 - 1 1 of the Periodic Table of the Elements.
• Particularly preferred active metals are ruthenium, copper and / or gold.
• the copper or ruthenium-supported catalysts can be obtained, for example, by impregnating the support material with aqueous solutions of CuCl 2 or RuCl 3 and optionally a promoter for doping, preferably in the form of their chlorides.
• the shaping of the catalyst can take place after or preferably before the impregnation of the support material.
• Gold-containing catalysts of the present invention can be obtained by applying gold in the form of the aqueous solution of a soluble gold compound, then drying or drying and calcining.
• gold is applied to the support as an aqueous solution of AuCl 3 or HAuCl 4 .
• the ruthenium, copper and / or gold catalysts of the invention for the catalytic hydrogen chloride oxidation may additionally contain compounds of one or more other noble metals selected from palladium, platinum, osmium, iridium, silver or rhenium.
• the catalysts may also be doped with one or more further metals.
• alkali metals such as lithium, sodium, potassium, rubidium and cesium, preferably lithium, sodium and potassium, more preferably potassium, alkaline earth metals such as magnesium, calcium, strontium and barium, preferably magnesium and calcium, more preferably magnesium, rare earth metals such Scandium, yttrium, lanthanum, cerium, praseodymium and neodymium, preferably scandium, yttrium, lanthanum and cerium, more preferably lanthanum and cerium, or mixtures thereof, furthermore titanium, manganese, molybdenum and tin.
• alkaline earth metals such as magnesium, calcium, strontium and barium, preferably magnesium and calcium, more preferably magnesium, rare earth metals such Scandium, yttrium, lanthanum, cerium, praseodymium and neodymium, preferably scandium, yttrium, lanthanum and cerium, more preferably lanthanum and cerium, or mixture
• the weights are based on the weight of the metal, even if the metals are usually present in oxidic form on the support.
• Very particularly preferred active metal is ruthenium, which is generally present in amounts of 0.001 to 10 wt .-%, based on the weight of the catalyst.
• the catalyst of the invention contains about 1 to 3% by weight, for example about 1, 6 wt .-% ruthenium on alpha-alumina as a carrier and next to no further active metals and promoter metals, wherein ruthenium is present as Ru ⁇ 2 .
• the catalysts of the invention are obtained by impregnation of the support material with aqueous solutions of salts of the metals.
• the metals other than gold are usually applied to the support as aqueous solutions of their chlorides, oxychlorides or oxides.
• the shaping of the catalyst can take place after or preferably before the impregnation of the support material.
• the catalysts of the invention are also used as fluidized bed catalysts in the form of powder having an average particle size of 10-200 ⁇ m. As fixed bed catalysts, they are generally used in the form of shaped catalyst bodies.
• the shaped bodies or powders may subsequently at temperatures of 100 to 400 0 C, preferably 100 to 300 ° C, for example under a nitrogen, argon or air atmosphere to be dried and optionally calcined.
• the shaped bodies or powders are first dried at 100 to 150 ° C and then calcined at 200 to 400 ° C.
• the oxides are formed from the chlorides, for example RuO 2 or CuO.
• the invention also provides a process for preparing catalysts by impregnating alpha-alumina as a support with one or more metal salt solutions containing the active metal (s) and optionally one or more promoter metals, drying and calcining the impregnated support.
• the molding To form shaped catalyst particles can be done before or after impregnation.
• the catalyst according to the invention can also be used in powder form.
• Suitable shaped catalyst bodies are any desired forms, preference being given to tablets, rings, cylinders, stars, carriage wheels or spheres, particular preference being given to rings, cylinders or star strands.
• the specific surface area of the alpha alumina carrier before the metal salt deposition is generally in the range of 0.1 to 10 m 2 / g.
• Alpha-alumina can be prepared by heating gamma-alumina to temperatures in excess of 1000 ° C, preferably it is prepared. Generally calcined for 2 to 24 hours.
• the present invention also provides a process for the catalytic oxidation of hydrogen chloride with oxygen to chlorine on the catalyst according to the invention.
• a hydrogen chloride stream and an oxygen-containing stream are fed into an oxidation zone and hydrogen chloride is partially oxidized to chlorine in the presence of the catalyst to give a product gas stream containing chlorine, unreacted oxygen, unreacted hydrogen chloride and water vapor.
• the hydrogen chloride stream which may originate from an isocyanate-producing plant, may contain impurities such as phosgene and carbon monoxide.
• Typical reaction temperatures are between 150 and 500 ° C, usual reaction pressures are between 1 and 25 bar, for example 4 bar.
• the reaction temperature is preferably> 300 ° C., more preferably between 350 ° C. and 400 ° C.
• oxygen in superstoichiometric amounts. For example, a 1.5 to 4-fold excess of oxygen is customary. Since no selectivity losses are to be feared, it may be economically advantageous to work at relatively high pressures and, accordingly, at longer residence times than normal pressure.
• reactors in which the catalytic hydrogen chloride oxidation according to the invention is carried out are fixed bed or fluidized bed reactors.
• the hydrogen chloride oxidation can be carried out in one or more stages.
• the catalyst bed or the catalyst fluidized bed may contain, in addition to the catalyst according to the invention, further suitable catalysts or additional inert material.
• the catalytic hydrogen chloride oxidation may be adiabatic or preferably isothermal or approximately isothermal, batchwise, preferably continuously or as a fixed or fixed bed process, preferably as a fixed bed process, more preferably in tube bundle reactors at reactor temperatures of 200 to 500 C, preferably 300 to 400 ° C, and a pressure from 1 to 25 bar, preferably 1 to 5 bar, are performed.
• An embodiment of the fixed-bed method consists in using a structured catalyst bed in which the catalyst activity increases in the direction of flow.
• Such structuring of the catalyst bed can be carried out by different impregnation of the catalyst support with active material or by different dilution of the catalyst bed with an inert material.
• rings, cylinders or spheres of titanium dioxide, zirconium dioxide or mixtures thereof, aluminum oxide, steatite, ceramic, glass, graphite or stainless steel can be used as the inert material.
• the inert material preferably has similar external dimensions as the shaped catalyst bodies.
• the conversion of hydrogen chloride in a single pass can be limited to 15 to 90%, preferably 40 to 85%. Unreacted hydrogen chloride can be partially or completely recycled to the catalytic hydrogen chloride oxidation after separation.
• the volume ratio of hydrogen chloride to oxygen at the reactor inlet is generally between 1: 1 and 20: 1, preferably between 1, 5: 1 and 8: 1, more preferably between 1, 5: 1 and 5: 1.
• the chlorine formed can subsequently be separated off in a customary manner.
• the separation usually comprises several stages, namely the separation and optionally recycling of unreacted hydrogen chloride from the product gas stream of the catalytic hydrogen chloride oxidation, drying of the resulting, essentially consisting of chlorine and oxygen residual gas stream and the separation of chlorine from the dried Electricity.
• the invention is further illustrated by the following examples.
• the attrition test simulates the mechanical stresses to which a fluidized material (e.g., a catalyst) is subjected in a gas / solid fluidized bed and, as a result, provides a rate of attrition (AB) and fines (FA) describing strength behavior.
• a fluidized material e.g., a catalyst
• the system is connected to the 4 bar compressed air network. A reducing valve lowers the pressure to 2 bar absolute before the system is started.
• the deposited solid is weighed after one hour (defined as fines FA) and after 5 hours (defined as attrition AB).
• a powdery gamma-alumina support of the Fa. Sasol (Puralox ® SCCa 30/170) was first converted into alpha-Al 2 O 3.
• the carrier consists of particles having a mean particle diameter of about 50 microns.
• 2000 g of the Puralox ® SCCa 30/170 at 1200-1300 ° C for 5 h were annealed.
• 1500 g of the resulting support were impregnated with an aqueous RuCl 3 hydrate solution (55.56 g RuCl 3 hydrate corresponding to 41, 8 wt .-% Ru in 480 g of water).
• the water absorption of the carrier was about 0.38 ml / g.
• the impregnated support was dried for 6 hours at 120 ° C and then calcined for 2 hours at 350 ° C.
• the cata- lysator contains about 2% R11O 2 on alpha Al 2 O 3. The most important properties of the catalyst are summarized in Table 1.
• the gamma-alumina carrier Puralox ® SCCa 30/170 was used directly for catalyst preparation without prior annealing. Approximately 1434 g of the carrier were impregnated with an aqueous RuCl 3 -hydroxide solution (54.1 g of RuCl 3 -hydrate corresponding to 36.5% Ru in 1045 g of water). The water absorption of the carrier was about 0.81 ml / g. The 90% water-impregnated support was dried at 120 ° C for 6 hours and calcined at 350 ° C for 2 hours. The catalyst thus prepared contains about 2% RuO 2 on a gamma Al 2 O 3 . The most important catalyst properties are summarized in Table 1.
• a Deacon reactor was operated in fluidized bed mode.
• the Deacon reactor consisted of a tube 4 cm in diameter and 1 m in length, containing 600 g of the catalyst.
• At 380-400 ° C and 4 bar reactor pressure 200 Nl / h HCl and 100 Nl / h O 2 were fed into the reactor, the HCI conversion was 60-80%.
• the catalyst properties of the used catalyst are summarized in Table 2.
• the catalyst according to the invention has a significantly higher mechanical stability compared with a corresponding catalyst on gamma-alumina as support. This is true even for the newly prepared catalyst, but especially for the used catalyst.

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• Chemical Kinetics & Catalysis (AREA)
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• 2005
  • 2005-08-25 DE DE102005040286A patent/DE102005040286A1/de not_active Withdrawn
• 2006
  • 2006-08-22 EP EP06792946A patent/EP1919611A1/de not_active Withdrawn
  • 2006-08-22 JP JP2008527462A patent/JP5230422B2/ja not_active Expired - Fee Related
  • 2006-08-22 CN CNA2006800351213A patent/CN101272852A/zh active Pending
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  • 2006-08-22 WO PCT/EP2006/065559 patent/WO2007023162A1/de active Application Filing
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• 2010
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