EP0451589A1 - Anoden für die elektrochemische Fluorierung und Fluorerzeugung sowie Verfahren zu deren Herstellung - Google Patents

Anoden für die elektrochemische Fluorierung und Fluorerzeugung sowie Verfahren zu deren Herstellung Download PDF

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Publication number
EP0451589A1
EP0451589A1 EP91104625A EP91104625A EP0451589A1 EP 0451589 A1 EP0451589 A1 EP 0451589A1 EP 91104625 A EP91104625 A EP 91104625A EP 91104625 A EP91104625 A EP 91104625A EP 0451589 A1 EP0451589 A1 EP 0451589A1
Authority
EP
European Patent Office
Prior art keywords
anodes
metal
metals
fluorine
nickel
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.)
Withdrawn
Application number
EP91104625A
Other languages
German (de)
English (en)
French (fr)
Inventor
Jürgen-Otto Dr. Besenhard
Markus Dahlhaus
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Bayer AG
Original Assignee
Bayer AG
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Bayer AG filed Critical Bayer AG
Publication of EP0451589A1 publication Critical patent/EP0451589A1/de
Withdrawn legal-status Critical Current

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B1/00—Electrolytic production of inorganic compounds or non-metals
    • C25B1/01—Products
    • C25B1/24—Halogens or compounds thereof
    • C25B1/245—Fluorine; Compounds thereof
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
    • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
    • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
    • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
    • C25B3/00—Electrolytic production of organic compounds
    • C25B3/20—Processes
    • C25B3/27—Halogenation
    • C25B3/28—Fluorination

Definitions

  • the invention relates to anodes for electrochemical fluorination and fluorine generation and to a method for their production.
  • Electrochemical fluorination in anhydrous or low-water condensed hydrofluoric acid is a technically important process, particularly for organic compounds, and is very gentle and selective compared to fluorination with elemental fluorine.
  • the decisive technical problem with this method is the corrosion or passivation of the anode, which is usually made of pure nickel.
  • the service life of the anodes is very short, especially at higher current densities, and on the other hand, because of the considerable polarization effects, much higher voltages must be applied than would be expected due to the thermodynamics of the fluorination reactions.
  • the invention relates to metal anodes for electrofluorination or for electrochemical fluorine generation, which have an electron-conducting or at least semiconducting layer made of one or more compounds of the metal or metals on which the anode is based, on which there may be another layer made of one or more fluorine compounds Anode of the underlying metal or metals.
  • Oxides or sulfides of the metal are preferred as metal compounds for the electron or at least semiconducting layer.
  • preferred metals for the anodes are also Cu, Nb, Ta, V, Mo, W, Ti, Zr, Hf, Fe, La and Th or their alloys.
  • Another object of the invention is a method for producing the metal anodes according to the invention, which is characterized in that the metals on which the anodes are based are oxidized on their surface to produce a layer and, if appropriate, the oxidized metal anodes are subsequently fluorinated to produce a further layer, e.g. in hydrofluoric acid.
  • the oxidation is preferably carried out thermally in air.
  • the oxidation for nickel anodes preferably takes place at temperatures above 800 ° C. (between 800 and 1300 ° C.).
  • the fluorination of the oxidized metal electrodes to produce the further layer can be carried out separately before the actual process of electrofluorination or fluorine generation or else during the process of electrofluorination or fluorine generation.
  • the advantage of the metal anodes according to the invention is that they are particularly corrosion-resistant over a longer period of time and that they allow a higher current density or have a lower overvoltage.
  • An electrode made of pure nickel (Ni> 99.7) is annealed in air at 1200 ° C for two hours.
  • the electrode turns blue-black due to the formation of oxide on the surface.
  • the thickness of the oxide layer is about 10 ⁇ m.
  • the electrode can then be used as an anode in a solution of 1 mol / l KF in practically anhydrous condensed hydrofluoric acid without further treatment. After 21 hours of exposure to 4.5 mA / cm2, no corrosion damage can be seen on the electrode with the naked eye.
  • the electrode is practically unchanged smooth and blue-black and free of nickel fluoride incrustations. At 50x magnification, the light microscope shows only a few minimal signs of corrosion or discoloration.
  • a comparative electrode made of non-pretreated pure nickel is encrusted with nickel fluoride after an identical 21-hour exposure.
  • An electrode made of pure nickel is annealed in air at 1200 ° C. as in Example 1, but for a period of 3 hours.
  • An electrode made of pure nickel is annealed for 2 hours while adding pure oxygen at approx. 1200 ° C.
  • the nickel oxide surface layer that forms is greenish black.
  • An electrode made of pure nickel is galvanically coated with an approx. 5 ⁇ m thick layer of copper. The mixture is then heated to 1200 ° C. in air for 2 hours.
  • the electrode turns blue-black.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Inorganic Chemistry (AREA)
  • Electrodes For Compound Or Non-Metal Manufacture (AREA)
  • Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
EP91104625A 1990-04-05 1991-03-23 Anoden für die elektrochemische Fluorierung und Fluorerzeugung sowie Verfahren zu deren Herstellung Withdrawn EP0451589A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4010961 1990-04-05
DE4010961A DE4010961A1 (de) 1990-04-05 1990-04-05 Anoden fuer die elektrochemische fluorierung und fluorerzeugung sowie verfahren zu deren herstellung

Publications (1)

Publication Number Publication Date
EP0451589A1 true EP0451589A1 (de) 1991-10-16

Family

ID=6403793

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91104625A Withdrawn EP0451589A1 (de) 1990-04-05 1991-03-23 Anoden für die elektrochemische Fluorierung und Fluorerzeugung sowie Verfahren zu deren Herstellung

Country Status (3)

Country Link
EP (1) EP0451589A1 (en))
JP (1) JPH05140783A (en))
DE (1) DE4010961A1 (en))

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585627A1 (de) * 1992-08-13 1994-03-09 Bayer Ag Verfahren zur Herstellung von Perfluoralkylsulfonylfluoriden sowie Elektroden zur Durchführung des Verfahrens

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3340273B2 (ja) * 1995-02-21 2002-11-05 三井化学株式会社 複合電極及びそれを用いる三フッ化窒素ガスの製造方法
KR100641603B1 (ko) * 2003-09-04 2006-11-02 주식회사 소디프신소재 고순도 불소의 제조방법

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2225399A1 (en)) * 1973-04-11 1974-11-08 Electricity Council
DE2725211A1 (de) * 1977-06-03 1978-12-14 Bayer Ag Verfahren zur herstellung von perfluoralkansulfonsaeurefluoriden

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2300422C3 (de) * 1973-01-05 1981-10-15 Hoechst Ag, 6000 Frankfurt Verfahren zur Herstellung einer Elektrode
JPS5573884A (en) * 1978-11-24 1980-06-03 Asahi Chem Ind Co Ltd Preparation of electrode
DE2903407C2 (de) * 1979-01-30 1983-12-15 BOMIN Bochumer Mineralöl GmbH & Co, 4630 Bochum Verwendung einer aus Nickelpulver heißgepreßten oder gesinterten porösen Elektrode
IT1127303B (it) * 1979-12-20 1986-05-21 Oronzio De Nora Impianti Tprocedimento per la preparazione di ossidi misti catalitici
DE3737235A1 (de) * 1987-11-03 1989-06-01 Heiner Dr Ing Debrodt Verfahren zum herstellen einer anode fuer elektrochemische prozesse

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2225399A1 (en)) * 1973-04-11 1974-11-08 Electricity Council
DE2725211A1 (de) * 1977-06-03 1978-12-14 Bayer Ag Verfahren zur herstellung von perfluoralkansulfonsaeurefluoriden

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585627A1 (de) * 1992-08-13 1994-03-09 Bayer Ag Verfahren zur Herstellung von Perfluoralkylsulfonylfluoriden sowie Elektroden zur Durchführung des Verfahrens
US5364507A (en) * 1992-08-13 1994-11-15 Bayer Ag Process for the production of perfluoroalkylsulphonyl fluorides and electrodes for performance of the process

Also Published As

Publication number Publication date
DE4010961A1 (de) 1991-10-10
JPH05140783A (ja) 1993-06-08
DE4010961C2 (en)) 1993-01-07

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