Classifications

• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
  • C01B15/01—Hydrogen peroxide
  • C01B15/022—Preparation from organic compounds
  • C01B15/023—Preparation from organic compounds by the alkyl-anthraquinone process

Definitions

• the invention relates to a process for the production of hydrogen peroxide, according to the anthraquinone cycle comprising a hydrogenation stage, an oxidation stage and an extraction stage.
• the process according to the invention largely suppresses the formation of anthraquinone epoxides in the oxidation stage.
• a large-scale process for the production of hydrogen peroxide is the so-called anthraquinone process.
• This process comprises a catalytic hydrogenation of a working solution containing one or more anthraquinone derivatives, an oxidation step, the hydrogenated working solution being oxidized with an oxygen-containing gas and an extraction step, wherein the hydrogen peroxide formed is extracted from the oxidized working solution with water or dilute hydrogen peroxide solution.
• the organic working solution becomes the
• the working solution contains one or more solvents, the task of which is to dissolve both the anthraquinone derivatives serving as reaction carriers and the anthrahydroquinone derivatives formed during the hydrogenation.
• the anthraquinone derivatives are in particular 2-alkylanthraquinones and their tetrahydro derivatives 2-
• alkyl-5, 6,7, 8-tetrahydroanthraquinones Both the alkylanthraquinones (hereinafter abbreviated as alkyl AQ) and their tetrahydro derivatives (hereinafter abbreviated as alkyl-THAQ) take part in the cycle.
• alkyl AQ alkylanthraquinones
• alkyl-THAQ tetrahydro derivatives
• the oxidation stage and thus the reaction stage in which the hydrogen peroxide is formed is of great importance for the overall process and the economy of the process. Accordingly, many processes aim to carry out the conversion of the 2-alkylanthraquinroquinones into the 2-alkylanthraquinones as quantitatively as possible, to minimize the reactor volume and the energy input and to suppress the formation of by-products, such as the epoxide, of the 2-alkyltetrahydroanthraquinone derivatives , This epoxy does not take part in the cycle itself, but has to be converted back into active anthraquinone in an additional complex regeneration stage.
• the formation of epoxides is reduced by oxidizing the hydrogenated working solution with pure oxygen or with oxygen-enriched air instead of with air.
• oxygen or oxygen-enriched air not only causes considerable costs, but also the epoxide formation is not suppressed to a sufficient extent, so that a regeneration stage of the working solution is still required, for example by contacting it with aluminum oxide at elevated temperature.
• the oxidation can be accelerated by passing a coalescence-inhibited system consisting of the hydrogenated working solution and an oxidizing gas through a DC reactor.
• the object of the present invention is that
• Epoxy are formed. According to a further object, the process should be able to be integrated in a simple manner into an existing plant for the production of hydrogen peroxide using the anthraquinone process.
• the invention thus relates to a process for the production of hydrogen peroxide according to the anthraquinone cycle, comprising (a) a catalytic hydrogenation of a working solution containing a 2-alkyl-tetrahydroanthraquinone (A-THAQ), a 2-alkyl-tetrahydroanthrahydroquinone (A-THAHQ ) containing hydrogenated working solution, (b) an oxidation of the hydrogenated working solution with an oxygen-containing gas, whereby an oxidized working solution containing hydrogen peroxide and A-THAQ is obtained, and (c) one
• Reactor essentially in the first part of the same, takes place.
• hydrogenated and oxidized working solution are mixed in a volume ratio in the range from 2 to 1 to 1 to 2 before or at the start of the oxidation reactor and the mixture is oxidized.
• the inventive oxidation of the mixture containing hydrogenated and oxidized working solution can be carried out with air or another gas containing oxygen, including pure oxygen.
• Temperature conditions of the oxidation level essentially correspond to those used in the prior art.
• the reaction temperature is usually in the range from 30 to 70 ° C., in particular 45 to 60 ° C.
• the one used for the oxidation is usually in the range from 30 to 70 ° C., in particular 45 to 60 ° C.
• Gas is usually fed to the oxidation reactor with a slight excess pressure, namely 0.1 to 0.5 MPa.
• air is used as the oxidizing gas.
• the mixture of hydrogenated and oxidized working solution can be passed in cocurrent or countercurrent through an oxidation reactor, usually one or more oxidation columns.
• Oxidation reactors such as are known in the prior art can be used for the oxidation - an example is given on refer to the embodiments according to the introductory Ullmann's Encyclopedia of Industrial Chemistry and EP 0 221 931 B1.
• an oxidation column is that of the as yet unpublished DE patent application 198 43 573.8: this is a bubble column which can be operated in cocurrent or countercurrent and has finely perforated trays, the cross-sectional area of the individual holes 0.003 to 3 mm 2 , in particular 0 , 05 to 0.5 mm 2 and the open area of the floors 2 to 20%, in particular 3 to 7%.
• each fine perforated floor contains a segment or chess-shaped element for the passage of liquid into the zone located below the floor.
• Working solution can be obtained in any manner known per se, and the hydrogenation of the working solution containing at least one reaction carrier can be carried out in a manner known per se using a suspension catalyst or a fixed bed catalyst.
• the working solution to be hydrogenated contains at least one 2-alkylanthraquinone and additionally the corresponding 2-alkyltetrahydroanthraquinone (A-THAQ).
• the A-THAQ can already be contained in the working solution or can be formed during the hydrogenation.
• the method according to the invention is not tied to the use of a special solvent or solvent mixture as a component of the working solution; rather, the solvents and solvent mixtures known in the art (see Ullmann's Encyclopedia) can be used.
• the working solution to be fed to the hydrogenation stage contains two different 2-alkylanthraquinones and at least the tetrahydro derivative one of the two 2-alkyla thrachinones.
• 2-ethylanthraquinone it is particularly expedient to use a 2-alkylanthraquinone with 4, 5 or 6 carbon atoms in the alkyl group as a reaction carrier.
• the reaction carrier mixture contains the tetrahydro derivative at least one of the two 2-alkylanthraquinones.
• the tests were carried out in a heated glass flask.
• the stirring speed was about 1000 rpm.
• the volume of the glass flask was about 200 ml, that of the working solution presented was 100 ml. Air was introduced into the solution at normal pressure. The one to be oxidized
• Working solution contained a mixture of 70 vol.% Isodurol and 30 vol.% Trioctyl phosphate as solvent and (a) 290 mmol or (b) 362 mmol tetrahydro-2-ethylanthrahydroquinone (THEAHQ) per kg working solution as reaction medium.
• the reaction temperature was 50 ° C.
• the air flow was 50 Nl / h.
• the oxidized working solution was analyzed analytically for the epoxy content. Comparative Example 1
• a working solution with the composition (a) was oxidized: after a reaction time of 90 minutes, the solution was completely oxidized.
• the THEAHQ concentration was 362 mmol / kg (corresponds to working solution (b)). After a reaction time of 80 min, THEAHQ was completely oxidized to THEAQ. The epoxy fraction formed was 0.5 mol%.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Inorganic Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)
• Epoxy Compounds (AREA)

Applications Claiming Priority (3)

Publications (1)

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• 2000
  • 2000-04-08 DE DE10017656A patent/DE10017656A1/de not_active Withdrawn
• 2001
  • 2001-03-14 KR KR1020027013445A patent/KR20030007505A/ko not_active Withdrawn
  • 2001-03-14 PL PL01357904A patent/PL357904A1/pl not_active Application Discontinuation
  • 2001-03-14 CN CN01807604A patent/CN1422234A/zh active Pending
  • 2001-03-14 JP JP2001575496A patent/JP2003530288A/ja active Pending
  • 2001-03-14 EP EP01925441A patent/EP1274651A1/de not_active Withdrawn
  • 2001-03-14 BR BR0107541-1A patent/BR0107541A/pt not_active Application Discontinuation
  • 2001-03-14 AU AU52193/01A patent/AU5219301A/en not_active Abandoned
  • 2001-03-14 WO PCT/EP2001/002839 patent/WO2001077013A1/de not_active Ceased
  • 2001-03-14 CA CA002398330A patent/CA2398330A1/en not_active Abandoned
  • 2001-04-05 US US09/825,853 patent/US20010028873A1/en not_active Abandoned
  • 2001-04-06 AR ARP010101659A patent/AR027779A1/es unknown
• 2002
  • 2002-10-07 ZA ZA200208052A patent/ZA200208052B/en unknown

Non-Patent Citations (1)

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