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WO2007051851A1 - Procede de production de composes aromatiques, en particulier de benzene, par aromatisation de composes non aromatiques a la vapeur d'eau et desalkylation d'hydrocarbures aromatiques a substitution alkyle a l'hydrogene - Google Patents

Procede de production de composes aromatiques, en particulier de benzene, par aromatisation de composes non aromatiques a la vapeur d'eau et desalkylation d'hydrocarbures aromatiques a substitution alkyle a l'hydrogene Download PDF

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WO2007051851A1
WO2007051851A1 PCT/EP2006/068117 EP2006068117W WO2007051851A1 WO 2007051851 A1 WO2007051851 A1 WO 2007051851A1 EP 2006068117 W EP2006068117 W EP 2006068117W WO 2007051851 A1 WO2007051851 A1 WO 2007051851A1
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catalyst
aromatic hydrocarbons
hydrogen
weight
alkyl
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German (de)
English (en)
Inventor
Dirk Neumann
Michael Koch
Götz-Peter SCHINDLER
Regina Benfer
Gerd Kaibel
Hans-Günter Wagner
Peter PÄSSLER
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BASF SE
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BASF SE
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    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C15/00—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts
    • C07C15/02—Monocyclic hydrocarbons
    • C07C15/04—Benzene
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C15/00—Cyclic hydrocarbons containing only six-membered aromatic rings as cyclic parts
    • C07C15/02—Monocyclic hydrocarbons
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
    • C07C4/08—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule
    • C07C4/12—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene
    • C07C4/14—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene splitting taking place at an aromatic-aliphatic bond
    • C07C4/18—Catalytic processes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
    • C07C2521/02—Boron or aluminium; Oxides or hydroxides thereof
    • C07C2521/04—Alumina
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
    • C07C2521/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/14—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of germanium, tin or lead
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
    • C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
    • C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
    • C07C2523/42—Platinum
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00—Technologies relating to chemical industry
    • Y02P20/50—Improvements relating to the production of bulk chemicals
    • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

  • the present invention relates to a process for the dealkylation of alkyl-substituted aromatic hydrocarbons, wherein in
  • Step (I) aromatizing non-aromatic hydrocarbons having 6 or more carbon atoms in the presence of water vapor and a catalyst;
  • Step (II) at least a portion of the product stream I obtained in step (I) (reaction product step-l) containing alkyl-substituted aromatic hydrocarbons, with the aid of hydrogen, optionally in the presence of a catalyst, is reacted by dealkylating the alkyl-substituted aromatic hydrocarbons.
  • Aromatic hydrocarbons are widely used in both the petrochemical and chemical industries. Large amounts of aromatic hydrocarbons are needed, for example, as additives for gasoline - to increase the octane number. In the chemical industry, benzene is a key starting material for a variety of organic compounds.
  • Aromatic hydrocarbons obtained by the former method are usually obtained as mixtures and can be added as such to gasoline.
  • steam cracking the aim is to obtain short-chain olefins and aromatic hydrocarbons are obtained as by-products, which are separated by complex separation operations and into the individual components, such as. Benzene, toluene, etc. can be separated.
  • the two processes mentioned have the disadvantage that the aromatic hydrocarbons are coupled with other products.
  • hydrodealkylation is a dealkylation of alkylaromatics in the presence of hydrogen, as described, for example, in Ullman's Encyclopedia of Industrial Chemistry 6th Edition, 2000, electronic release, Chapter 5.3.1 and Industrial Organic Chemistry (K. Weissermel, H. J. Arpe), 5th Edition, 1998, Chapter 12.3.1.
  • Examples of catalytic processes are the Hydeal process (UOP and Ashland OiI Co.), the Detol and / or Pyrotol process (Air Products and Chemicals, Houdry Division) and the Bextol process (Shell). Typically, these processes are carried out at temperatures between 550 and 650 ° C and pressures between 5 and 55 bar with chromium oxide / alumina catalysts, the benzene purity is usually> 99.9%.
  • Examples of thermal processes are the MHC process (Mitsubishi Petrochemical Co.), the HDA process (Arco and Hydrocarbon Research) and the THD process (GuIf OiI).
  • No. 4,158,025 describes a process in which, in a first step, naphtha is reacted in the presence of hydrogen to form aromatic hydrocarbons, then in a second stage a dealkylation is carried out and in a third stage the products obtained are separated.
  • step I aromatization of non-aromatic hydrocarbons having 6 or more carbon atoms in the presence of water vapor and a catalyst
  • step II Hydrodealklitation the thus obtained aromatic hydrocarbons
  • the present invention thus relates to a process for the dealkylation of alkyl-substituted aromatic hydrocarbons, wherein in
  • Step (I) aromatizing non-aromatic hydrocarbons having 6 or more carbon atoms in the presence of water vapor and a catalyst;
  • Step (II) at least a portion of the product stream I obtained in step (I), which contains alkyl-substituted aromatic hydrocarbons, is reacted with the aid of hydrogen, optionally in the presence of a catalyst, by dealkylating the alkyl-substituted aromatic hydrocarbons.
  • non-aromatic hydrocarbons can be aromatized in step (I).
  • the non-aromatic hydrocarbons usually have at least 6 carbon atoms, in particular 6 to 20 carbon atoms.
  • the non-aromatic hydrocarbons are paraffins, naphthenes, or mixtures thereof.
  • the non-aromatic hydrocarbons may also include olefins on a case-by-case basis. The proportion is usually ⁇ 1 wt.%.
  • the feed stream usually used in step (I) generally contains aromatic and non-aromatic hydrocarbons having 6 to 20, preferably 7 to 20, in particular 7 to 12 carbon atoms.
  • the proportion of non-aromatic compounds is at least 1 wt .-%, preferably at least 5 wt .-% and in particular at least 10 wt .-%.
  • the proportion of non-aromatics is from 5 to 80% by weight, preferably from 10 to 50% by weight and in particular from 10 to 30% by weight.
  • the feed contains only non-aromatic hydrocarbons.
  • the BTX cut is a mixture of aromatic and non-aromatic hydrocarbons composed of between 6 and 9 hydrocarbons.
  • typical examples of the non-aromatic hydrocarbons are n-hexane, n-heptane, n-octane, cyclohexane, methylcyclopentane and methylcyclohexyl.
  • the feed stream may contain up to 40% by weight, preferably up to 10% by weight, more preferably up to 2% by weight, of hydrocarbons having 5 and / or 6 carbon atoms.
  • the feed stream of step (I) may contain sulfur containing compounds, e.g. Mercaptans, thiophene, benzothiophene, alkyl-substituted thiophenes and / or benzothiophenes.
  • sulfur containing compounds e.g. Mercaptans, thiophene, benzothiophene, alkyl-substituted thiophenes and / or benzothiophenes.
  • the sulfur content of the feed stream may be up to 100 ppm, usually 10 ppm or less, more preferably 2 ppm or less.
  • the so-called TX cut of a steam cracker is used.
  • the aromatization according to step (I) is usually carried out between 300 and 800.degree. C., preferably between 400 and 700.degree. C., in particular between 500 and 600.degree.
  • the pressure is in this case in a range of 1 to 50 bar, preferably from 3 to 30 bar, in particular from 5 to 25 bar.
  • the LHSV ("Liquid Hourly Space Velocity") of step (I) is usually from 0.1 to 10 parts by volume of feed stream per part by volume of catalyst per hour (l / l "h), preferably from 0.5 to 5 l / l »h, especially at 1 to 3 (l / l» h).
  • the molar ratio of steam / carbon (steam / carbon) of the feed stream used in step (I) is usually from 0.01 to 20, preferably from 0.1 to 15, in particular from 0.2 to 10th
  • catalysts for the aromatization in the presence of water vapor conventional catalysts known to those skilled in the art can be used.
  • numerous catalysts have been proposed which contain a porous support and generally at least one metal deposited on this support. Often, alumina is used as the carrier here.
  • US 4,304,658 describes rhodium supported on alumina.
  • copper may also be supported on the alumina support, as described in US Pat. No. 4,320,240 or chromium and potassium as disclosed in US 4,304,658 or rhenium, copper and optionally potassium as taught in RU 2,193,920.
  • catalysts which contain, on the one hand, mixed carriers containing aluminum oxide and tin oxide, titanium oxide and / or zirconium oxide and, on the other hand, a metal selected from the group chromium, molybdenum and tungsten (US Pat. No. 3,197,523).
  • catalysts which contain a metal of the platinum group on a support.
  • EP 454 022 teaches a carrier which also contains calcium aluminate in addition to zinc aluminate, which leads to an increase in activity and selectivity of the catalyst.
  • catalysts which contain a zirconium oxide-containing support, as well as platinum and tin, are suitable.
  • catalysts (catalyst step-I-Pt / Sn) containing a-1) a zirconia-containing support; b-l) platinum, in particular 0.01 to 5 wt .-%, based on the total weight of
  • the catalyst step I PtySn used contains, as component a-1), a zirconium oxide-containing support.
  • a stabilized zirconia-containing carrier It is also possible to use a stabilized zirconia-containing carrier.
  • Suitable stabilizers are all compounds which are tetragonal or monoclinic Stabilize structure of zirconia.
  • the stabilizers are used which cause and / or stabilize the tetragonal structure of the zirconia.
  • the stabilized zirconia-containing carrier contains cerium, lanthanum and / or silicon, preferably cerium and / or lanthanum.
  • the stabilized zirconium oxide-containing support contains in particular cerium (III) oxide, lanthanum (III) oxide and / or silicon (IV) oxide, preferably cerium (III) oxide and / or lanthanum (III) oxide.
  • the stabilized zirconia-containing carrier usually contains up to 40% by weight, preferably 10 to 30% by weight, especially 15 to 30% by weight, based on the weight of Zirconium oxide, cerium (III) oxide.
  • the stabilized zirconia-containing support usually contains up to 20% by weight, preferably from 2 to 15% by weight, in particular from 5 to 15% by weight, based on the weight of zirconium oxide , Lanthanum (III) oxide.
  • the stabilized zirconium oxide-containing support usually contains up to 10% by weight, preferably 1 to 7% by weight, in particular 2 to 5% by weight, based on the Weight of zirconium oxide, silicon (IV) oxide.
  • the stabilized zirconia-containing carrier usually contains up to 40% by weight, preferably 5 to 30% by weight. %, in particular 10 to 25 wt .-%, based on the weight of zirconium oxide, cerium (III) oxide and usually up to 20 wt .-%, preferably 1 to 15 wt .-%, in particular 2 to 10 wt. -%, based on the weight of zirconium oxide, lanthanum (III) oxide.
  • the zirconia-containing carrier may also contain adjuvants. These are suitable for facilitating the shaping of the zirconia-containing support.
  • Typical auxiliaries are, for example, graphite, waxes, silicon dioxide and aluminum oxide. These adjuvants can either be added by themselves or in the form of their precursors, which convert to the corresponding excipient during calcining. Examples of these are silica precursors, e.g. Tetraalkyl orthosilicates and colloidal silica, as well as alumina precursors, e.g. Boehmite, such as Pural® (Sasol).
  • auxiliaries used are graphite, waxes and aluminum oxides, in particular aluminum oxides.
  • the zirconia-containing carrier can contain up to 40% by weight, based on the total weight of the zirconia-containing carrier, of auxiliaries.
  • the zirconium oxide-containing support comprises from 5 to 40% by weight, preferably from 10 to 35% by weight, based on the total weight of the zirconium oxide support, of auxiliaries.
  • the catalyst step I-Pt / Sn contains as component bl) 0.01 to 5 wt .-%, based on the total weight of the catalyst step-I-Pt / Sn, platinum.
  • the catalyst step-I-Pt / Sn contains 0.1 to 2 wt .-%, preferably 0.3 to 1 wt .-%, based on the total weight of the catalyst step-I, Platinum.
  • the catalyst step-I-Pt / Sn as component c-1) contains from 0.01 to 20% by weight, based on the total weight of the catalyst step-I-Pt / Sn, of tin.
  • the catalyst step-I-Pt / Sn contains 0.5 to 10% by weight, preferably 1 to 5% by weight, based on the total weight of the catalyst-step-I-Pt / Sn, tin ,
  • the weight ratio of tin to platinum is generally at least 1, preferably at least 2, in particular at least 3.
  • the catalyst step I-Pt / Sn as component d-1) contains at least one further promoter.
  • promoters are metals selected from the group of scandium, yttrium, lanthanum, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, technetium, rhenium, rhodium, iron, ruthenium, cobalt, iridium, nickel, palladium, Copper, silver, gold, zinc, indium, germanium, lead, arsenic, antimony, bismuth, cerium, praseodymium, neodymium and europium, or mixtures thereof.
  • vanadium, chromium, rhenium, iron, nickel, copper or mixtures thereof are used as promoters.
  • vanadium, chromium, copper or mixtures thereof are used.
  • At least one further promoter for example two further promoters, from the above-mentioned group is used.
  • the catalyst step I-Pt / Sn contains 0.01 to 20 wt .-%, preferably 0.1 to 15 wt .-%, in particular 0.5 to 10 wt .-%, based on the total weight of the catalyst step-I-Pt / Sn, another promoter.
  • the catalyst step I-Pt / Sn as component el) contains at least one metal whose metal compound is alkaline, preferably at least one metal oxide which reacts alkaline, in particular at least one oxide of an alkali metal, alkaline earth metal or lanthanum.
  • the alkali metal is preferably potassium or cesium and alkaline earth metal preferably barium into consideration.
  • oxides of potassium or lanthanum are used.
  • a metal compound wherein the metal in question is selected from the group of alkali metals, alkaline earth metals and lanthanum, and which reacts alkaline, preferably a metal oxide, as mentioned above, is used.
  • two metal compounds wherein the metals in question are selected from the group of alkali metals, alkaline earth metals and lanthanum, and which react alkaline, preferably two metal oxides as listed above, are used.
  • the catalyst step I-Pt / Sn contains 0.01 to 20 wt .-%, preferably 0.1 to 15 wt .-%, in particular 0.5 to 10 wt .-%, based on the total weight of the catalyst step-I, at least one metal whose metal compound used is alkaline, preferably this metal compound contains an alkali metal, alkaline earth metal or lanthanum.
  • the catalyst step I-Pt / Sn usually has a BET surface area (determined according to DIN 66131) of up to 500 m 2 / g, preferably from 10 to 300 m 2 / g, in particular from 20 to 200 m 2 / g.
  • the pore volume of the catalyst step I-Pt / Sn (determined by means of Hg porosimetry according to DIN 66133) is 0.1 to 1 ml / g, preferably 0.15 to 0.6 ml / g, in particular at 0.2 to 0.4 ml / g.
  • the zirconia phases of the catalyst step-I-Pt / Sn are tetragonal and / or monoclinic (determined by X-ray diffraction (XRD)).
  • the catalyst step-I-Pt / Sn a-1) contains a zirconia-containing support
  • the catalyst step-I-Pt / Sn al) comprises a zirconia-containing support; bl) from 0.01 to 5% by weight, based on the total weight of the catalyst step I
  • Pt / Sn, tin; e-1) at least one metal whose metal compound is alkaline; wherein the weight ratio of tin to platinum is at least 1.
  • the catalyst step-I-Pt / Sn a-1) comprises a zirconia-containing support; b-1) from 0.01 to 5% by weight, based on the total weight of the catalyst, of step-I-Pt / Sn, platinum; c-1) from 0.01 to 20% by weight, based on the total weight of the catalyst, of step-I-Pt / Sn, tin; d-l) at least one further promoter; e-1) at least one metal whose metal compound is alkaline; wherein the weight ratio of tin to platinum is at least 1.
  • the catalyst step-I-Pt / Sn a-1) comprises a zirconia-containing support consisting essentially of zirconia; b-l) from 0.01 to 5% by weight, based on the total weight of the catalyst step I
  • Pt / Sn, tin; e-1) at least one metal whose metal compound is alkaline; wherein the weight ratio of tin to platinum is at least 1.
  • the catalyst step-I-Pt / Sn a-1) comprises a zirconia-containing support which a1) contains at least one stabilizer; b-l) from 0.01 to 5% by weight, based on the total weight of the catalyst step I
  • Pt / Sn, tin; e-1) at least one metal whose metal compound is alkaline;
  • Weight ratio of tin to platinum is at least 1.
  • Pt / Sn, tin; e-1) at least one metal whose metal compound is alkaline; wherein the weight ratio of tin to platinum is at least 1.
  • the preparation of the catalyst step-I-Pt / Sn can suc conditions by conventional methods.
  • the zirconia-containing support from corresponding compounds which convert to zirconia upon calcining.
  • hydroxides, carbonates and carboxylates are suitable.
  • the zirconium oxide or the corresponding precursor, which is converted into zirconium oxide during calcining can be prepared by methods known per se, such as e.g. by the sol-gel method, by precipitation, dehydration of the corresponding carboxylates, dry mixing, slurrying or spray-drying.
  • the precipitation usually employs soluble zirconium salts, e.g. the corresponding halides, preferably chloride, alkoxides, nitrate, etc., preferably nitrate.
  • Stabilized zirconia-containing supports can i.a. can be prepared by reacting the zirconia described above or the corresponding precursor with soluble salts of the stabilizers, such as. the corresponding halides, preferably chlorides, alkoxides, nitrates, etc., soaks.
  • soluble salts of the stabilizers such as. the corresponding halides, preferably chlorides, alkoxides, nitrates, etc.
  • Suitable soluble salts of the stabilizers are, in turn, generally suitable halides, preferably chlorides, alkoxides, nitrates, etc.
  • the stabilized zirconium oxide-containing support from compounds which convert to zirconium oxide or cerium (III) oxide, lanthanum (III) oxide, silicon (IV) oxide on calcination.
  • compounds which convert to zirconium oxide or cerium (III) oxide, lanthanum (III) oxide, silicon (IV) oxide on calcination.
  • hydroxides, carbonates and carboxylates are suitable. These are for example precipitated together, spray-dried together etc.
  • the zirconia described above, the stabilized zirconia described above or the corresponding precursors can be mixed with auxiliaries which are suitable for facilitating the shaping of the zirconia support. Subsequently, the shaping takes place.
  • auxiliaries which are suitable for facilitating the shaping of the zirconia support. Subsequently, the shaping takes place.
  • strands, tablets, spheres, chippings, monoliths, etc. are prepared by processes known to those skilled in the art.
  • the zirconium oxide described above, the above-described stabilized zirconium oxide or the corresponding precursors, which are optionally mixed with auxiliaries, are calcined. This is usually done with air or a mixture of air and nitrogen, at a temperature of 300 to 800 ° C, preferably at 500 to 600 ° C. It may be advantageous to add water vapor to the air or to the air / nitrogen mixture.
  • the carrier is impregnated with a solution of suitable platinum precursors or suitable tin precursors.
  • the impregnation can be carried out by the incipient-wetness method, wherein the pore volume of the support is filled up with approximately the same volume of impregnating solution and, optionally after ripening, the support is dried; or you work with an excess of solution, the volume of this solution is greater than the pore volume of the carrier.
  • the carrier is mixed with in the impregnating solution and stirred for a sufficient time. Furthermore, it is possible to spray the carrier with a solution of the platinum precursor or of the tin precursor.
  • the order of the impregnations does not matter. But it may also be advantageous to apply the individual precursors in a certain order. It is also possible to impregnate with a solution containing both the platinum and the tin precursor. But also other manufacturing methods known to the person skilled in the art, such as e.g. Precipitation, Chemical Vapor Deposition, Soltränkung etc. are possible.
  • Suitable platinum precursors are platinum salts, i.a. Halides, in particular chloride, nitrate, acetate, alkaline carbonates, formate, oxalate, citrate, tartrate, but also platinum complexes.
  • the latter may contain, as neutral ligands, Lewis bases, such as amines or phosphanes, and as anionic ligands, halides, such as chloride, bromide or nitrate, etc.
  • Suitable tin precursors are tin salts, in particular tin (II) salts, i.a. Halides, especially chloride, sulfate, acetate, formate, oxalate, citrate, tartrate, but also alkali and / or Erdalkalistannate such. Sodium stannate.
  • Catalyst Step-I containing one or more further promoters are prepared by applying the promoter precursor or promoter precursors in analogy to the platinum or tin plating processes.
  • Suitable promoter precursors include halides, in particular chlorides, nitrates, acetates, alkaline carbonates, formates, oxalates, citrates, tartrates, corresponding organometallic compounds, but also promoter complexes.
  • the latter may contain, as ligands, acetylacetonate, amino alcohols, carboxylates, such as oxalates, citrates, etc., or hydroxycarboxylic acid salts, etc.
  • the corresponding promotor precursor can be applied together with the platinum and / or tin precursor. But it is also possible to apply them one after the other. It can also be advantageous to apply the individual precursors in a certain order.
  • the promoter precursors can be applied together or separately. It is also possible to apply the platinum and / or tin precursor together or separately with one or more promoter precursors. In the case of a separate application, it may also be advantageous to apply the individual precursors in a certain order.
  • catalyst step I which contain at least one metal whose metal compound is alkaline
  • the alkaline metal precursor or the alkaline metal precursors are applied analogously to the processes for platinum or tin plating.
  • alkaline metal precursors are usually used compounds which convert to the corresponding oxides during calcining. Suitable for this are hydroxides, carbonates, carboxylates, e.g. Formates, acetates, oxalates, nitrates, hydroxycarbonates etc.
  • the respective precursors can be applied together or separately. In the case of a separate application, it may also be advantageous to apply the individual precursors in a certain order.
  • Coke and / or coke precursors may form at the active sites and in the pores of the catalyst Step-I.
  • Coke is usually high-boiling unsaturated hydrocarbons.
  • Coke precursors are typically low boiling alkenes, alkynes and / or saturated high molecular weight hydrocarbons.
  • the deposition of the coke or coke precursor causes the activity and / or selectivity of the catalyst step-I is adversely affected.
  • the aim of the regeneration is the removal of the coke or coke precursor without adversely affecting the physical properties of the catalyst step-l.
  • the coke precursors can be removed by evaporation in the presence of an intergas at elevated temperature (T> 250 ° C.) and / or hydrogenation in the presence of a hydrogen-containing gas mixture and / or combustion in the presence of an oxygen-containing gas mixture.
  • oxidative regeneration The regeneration of the catalyst step-I can take place in-situ or ex-situ, preference is given to in situ regeneration.
  • the inlet temperature for the oxidative regeneration is usually between 350 and 550 ° C.
  • the oxygen concentration of the oxygen-containing gas mixture is usually between 0.1 and 10% by volume.
  • the pressure is typically between 0.1 and 10 bar.
  • the oxidative regeneration of the catalyst step-I is carried out in the presence of water vapor.
  • the reactors used are generally fixed-bed reactors, tube-bundle reactors or fluid-bed reactors.
  • adiabatic driving usually a fixed bed reactor is used in isothermal driving usually a tube bundle reactor.
  • the reactor autothermally with the supply of air, oxygen or an oxygen-containing gas.
  • the hydrogen formed in the reaction (and / or the hydrocarbons and / or the carbon monoxide formed in the reaction and / or the coke formed in the reaction) is oxygenized with heat generation oxidized.
  • a corresponding oxygen-containing gas is fed into the reactor.
  • the heat is supplied outside the reactor, this is preferably done via a heat exchanger.
  • the heat is generated within the reactor by reacting the hydrogen formed during the aromatization and / or the remaining hydrocarbons and / or the methane formed during the aromatization and / or the coke formed during the aromatization with oxygen.
  • oxygen for this purpose, air, oxygen and / or an oxygen-containing gas are fed into the reactor.
  • Step (I) of the process according to the invention can be carried out in a single reactor. However, it is also possible to carry out the reaction in a plurality of reactors connected in series (reactor cascade), with intermediate heating (s) optionally being inserted between the individual reactors.
  • the autothermal procedure by supplying air, oxygen or an oxygen-containing gas or a reactor cascade with intermediate heaters is particularly useful if the feed stream contains a larger amount of non-aromatic hydrocarbons, especially if their content is> 30 wt .-%.
  • reaction product step I is rich in hydrogen and aromatic hydrocarbons, in particular containing, in addition to benzene, alkyl-substituted aromatic hydrocarbons which usually have 7 to 20 carbon atoms.
  • monoalkyl-substituted aromatic hydrocarbons are, for example, toluene, ethylbenzene or propylbenzene; with multiply alkyl-substituted aromatic hydrocarbons to xylene, mesitylene, etc.
  • alkylated aromatic hydrocarbons with condensed cores such as alkyl-substituted naphthalenes can be included.
  • the reaction product step-I may contain unreacted non-aromatics and aromatics as well as cracking products.
  • reaction product step-I is now - without further separation - directly subjected to step (II), wherein in the reaction product step-I contained alkyl-substituted aromatic hydrocarbons, optionally in the presence of a catalyst, by means of reaction in the reaction step-I obtained hydrogen, be dealkylated.
  • a condensation of the reaction product step-I is carried out and the water, for example by phase separation, separated.
  • the hydrogen-rich gas can be partially or completely separated, or preferably used in step Il. Possibly. it is necessary to meter in hydrogen-containing gas, such as pure hydrogen, in step (II), so that for the Hydrodealklitation the necessary amount of hydrogen is present.
  • step (I) it may be necessary to interpose a densification step between step (I) and step (II) if the hydrodealkyation is carried out at higher pressures than the aromatization.
  • reaction product step-I is completely subjected to step (II).
  • reaction product step-I is subjected to step (II) without compression or relaxation.
  • the two stages are operated at equal pressures.
  • the organic phase which forms during the condensation can be brought to the desired pressure for the hydrodealkyation with the aid of a pump and the gas phase can be brought to the desired pressure with a compressor.
  • the feed stream used in the hydrodealkylation in step (II) as a rule contains at least 50% by weight, preferably at least 80% by weight, particularly preferably at least 90% by weight, of an alkyl-substituted aromatic hydrocarbon or a mixture of these.
  • the hydrodealkyation in step (II) is usually carried out between 400 and 900 ° C., preferably between 500 and 900 ° C.
  • the pressure is in this case in a range of 5 to 100 bar, preferably from 10 to 80 bar, in particular from 20 to 70 bar.
  • the dehydroalkylation can be carried out with or without addition of catalyst. If no catalyst is used, the reaction is carried out in a correspondingly higher temperature range.
  • step (II) of the process according to the invention is carried out in the presence of a catalyst (catalyst step II).
  • a catalyst for this purpose, known in the art Hydrodealkyl istskatalysatoren be used.
  • these are catalysts which contain a porous support and optionally at least one metal deposited on this support.
  • Cr 2 O 3 have, MO 2 O 3, or CoO 2 on supports such as Al 2 O 3, as suited proven (K. Weissermel, HJHarpe, Industrial Organic Chemistry, 4th edition, p 358).
  • zeolite-containing supports US Pat. No. 4,341,622
  • they may contain Co, Ni, Pt and / or Pd (US Pat. No. 5,865,986).
  • catalysts containing a metal of the platinum group, Sn, Ti, Zr Cr, Mo, W (US 3,204,007, US 3,197,523).
  • the reactor autothermally with the supply of air, oxygen or an oxygen-containing gas.
  • the hydrogen formed in the reaction (and / or the hydrocarbons and / or the carbon monoxide formed in the reaction and / or the coke formed in the reaction) is oxidized with oxygen with the generation of heat.
  • a corresponding oxygen-containing gas is fed into the reactor.
  • the introduction of the heat can take place both inside and outside the reactor.
  • the heat is supplied outside the reactor, this is preferably done via a heat exchanger.
  • the heat is generated within the reactor by reacting the hydrogen formed in the dealkylation and / or the remaining hydrocarbons and / or the carbon monoxide formed during the dealkylation and / or the coke formed in the dealkylation with oxygen.
  • oxygen for this purpose, air, oxygen and / or an oxygen-containing gas are fed into the reactor.
  • coke and / or coke precursors may form at the active sites and in the pores of the catalyst step-II.
  • Coke is usually high-boiling unsaturated Hydrocarbons.
  • Coke precursors are typically low boiling alkenes, alkynes and / or saturated high molecular weight hydrocarbons.
  • the deposition of the coke or the coke precursor causes the activity and / or selectivity of the catalyst step-II is adversely affected. In order to guarantee an optimal driving style, there is therefore the need to regenerate the catalyst at regular intervals.
  • the aim of the regeneration is the removal of the coke or coke precursor, without adversely affecting the physical properties of the catalyst step II.
  • the coke precursors can be removed by evaporation in the presence of an intergas at elevated temperature (T> 250 ° C.) and / or hydrogenation in the presence of a hydrogen-containing gas mixture and / or combustion in the presence of an oxygen-containing gas mixture.
  • the regeneration of the catalyst can be carried out in-situ or ex-situ, preference is given to in situ regeneration.
  • the inlet temperature for the oxidative regeneration is usually between 350 and 550 ° C.
  • the oxygen concentration of the oxygen-containing gas mixture is usually between 0.1 and 10% by volume.
  • the pressure is typically between 0.1 and 10 bar.
  • the oxidative regeneration of the catalyst step II is carried out in the presence of water vapor.
  • reaction product step H is rich in methane, optionally lower alkanes, e.g. Ethane, and dealkylated aromatic hydrocarbons, especially benzene. Furthermore, it optionally contains excess hydrogen.
  • the dealkylated aromatic hydrocarbons formed are separated by conventional methods.
  • the reaction product step II is relaxed and cooled. It is expedient to integrate the released heat in the process (heat combination), for example, the Feed stream to the reaction step I or other heated streams (eg evaporator of the column) to heat. Upon cooling, a gas phase rich in methane and optionally hydrogen, and a liquid phase is formed.
  • the gas phase may e.g. be worked up in a coldbox and so the hydrogen are separated. It is also possible that the hydrogen is e.g. is separated by pressure swing adsorption (PSA).
  • PSA pressure swing adsorption
  • the hydrogen is recycled back into the process, preferably in step (II). However, it is also possible for the gas phase per se to be returned to the process, preferably step (II).
  • the liquid phase formed during the cooling which contains the dealkylated aromatic hydrocarbon, preferably benzene, and excess water (if used without intermediate condensation) of the process, is fed to a phase separator and the organic phase is separated from the water phase.
  • the organic phase containing the dealkylated aromatic hydrocarbon, preferably benzene may be further purified, for example by distillation. The products obtained in the distillation may optionally be recycled to steps (I) and / or (II).
  • benzene and optionally impurities are removed overhead and C7 + hydrocarbons via the bottom in a distillation column.
  • the C7 + mixture is recycled either in step (I) (if non-aromatic hydrocarbons are still present) or step (II) (if no or only a small amount of non-aromatic hydrocarbons are present).
  • the benzene fraction can be passed to a further distillation column in which the dissolved water and the low boilers are passed overhead via azeotropic distillation Reinbenzol be separated via sump.
  • the columns are designed as columns with side draw or as a dividing wall column.
  • step (I) and / or step (II) units for reducing the olefin and sulfur content are incorporated into the process.
  • method steps according to the prior art are used.
  • step (I) makes it possible to produce benzene in high purity without the need for complicated extractive distillations.
  • step (I) by coupling steps (I) and (II), the hydrogen to be externally supplied to the system is reduced compared to a normal hydrodealing, since the hydrogen produced in step (I) is used immediately in step (II) can be.

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Abstract

La présente invention concerne un procédé de désalkylation d'hydrocarbures aromatiques à substitution alkyle, procédé selon lequel, à l'étape (I), des hydrocarbures non aromatiques présentant au moins 6 atomes de carbone sont aromatisés en présence de vapeur d'eau et d'un catalyseur et, à l'étape (II), au moins une partie du flux de produit obtenu à l'étape (I), qui contient des hydrocarbures aromatiques à substitution alkyle, est mise en réaction à l'aide d'hydrogène éventuellement en présence d'un catalyseur, les hydrocarbures aromatiques à substitution alkyle étant désalkylés.
PCT/EP2006/068117 2005-11-06 2006-11-06 Procede de production de composes aromatiques, en particulier de benzene, par aromatisation de composes non aromatiques a la vapeur d'eau et desalkylation d'hydrocarbures aromatiques a substitution alkyle a l'hydrogene Ceased WO2007051851A1 (fr)

Applications Claiming Priority (2)

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DE102005053231.4 2005-11-06
DE102005053231A DE102005053231A1 (de) 2005-11-06 2005-11-06 Verfahren zur Aromatisierung von Nichtaromaten mit Wasserdampf und anschließende Dealkylierung von Alkyl-substituierten aromatischen Kohlenwasserstoffen mit Wasserstoff

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Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011138355A2 (fr) 2010-05-07 2011-11-10 Basf Se Procédé de production de cellulose et d'au moins une matière valorisable organique liquide ou liquéfiable avec recyclage des effluents gazeux
WO2011138356A1 (fr) 2010-05-07 2011-11-10 Basf Se Procédé de production de gaz de synthèse et d'au moins une matière valorisable organique liquide ou liquéfiable
WO2011138357A1 (fr) 2010-05-07 2011-11-10 Basf Se Procédé de préparation d'au moins une matière valorisable aromatique de faible poids moléculaire à partir d'une matière de départ contenant de la lignine
WO2012013735A1 (fr) 2010-07-29 2012-02-02 Basf Se Composition contenant un catalyseur et de la lignine, et utilisation de ladite composition pour la production d'une composition aromatique
WO2012160072A1 (fr) 2011-05-24 2012-11-29 Basf Se Procédé de production de polyisocyanates à partir de biomasse
WO2013092844A2 (fr) 2011-12-23 2013-06-27 Basf Se Dispositif et procédé pour traiter un flux de matières contenant de l'hydrogène et du méthane
US8933262B2 (en) 2011-05-24 2015-01-13 Basf Se Process for preparing polyisocyanates from biomass

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1157114A (en) * 1966-04-29 1969-07-02 Power Gas Ltd Process for the Production of Aromatic Hydrocarbons and a Fuel Gas from Petroleum Oils

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1157114A (en) * 1966-04-29 1969-07-02 Power Gas Ltd Process for the Production of Aromatic Hydrocarbons and a Fuel Gas from Petroleum Oils

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011138355A2 (fr) 2010-05-07 2011-11-10 Basf Se Procédé de production de cellulose et d'au moins une matière valorisable organique liquide ou liquéfiable avec recyclage des effluents gazeux
WO2011138356A1 (fr) 2010-05-07 2011-11-10 Basf Se Procédé de production de gaz de synthèse et d'au moins une matière valorisable organique liquide ou liquéfiable
WO2011138357A1 (fr) 2010-05-07 2011-11-10 Basf Se Procédé de préparation d'au moins une matière valorisable aromatique de faible poids moléculaire à partir d'une matière de départ contenant de la lignine
WO2012013735A1 (fr) 2010-07-29 2012-02-02 Basf Se Composition contenant un catalyseur et de la lignine, et utilisation de ladite composition pour la production d'une composition aromatique
WO2012160072A1 (fr) 2011-05-24 2012-11-29 Basf Se Procédé de production de polyisocyanates à partir de biomasse
US8933262B2 (en) 2011-05-24 2015-01-13 Basf Se Process for preparing polyisocyanates from biomass
WO2013092844A2 (fr) 2011-12-23 2013-06-27 Basf Se Dispositif et procédé pour traiter un flux de matières contenant de l'hydrogène et du méthane

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