EP0451589A1 - Anodes for the electrochemical fluorination and fluorine production and their manufacturing process - Google Patents

Anodes for the electrochemical fluorination and fluorine production and their manufacturing process Download PDF

Info

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Withdrawn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)
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/en
Withdrawn legal-status Critical Current

Links

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.

Abstract

The invention relates to anodes for electrochemical fluorination and fluorine production which are composed of a metal or metals and which have an electron-conducting or at least semiconducting layer of one or more compounds of the basic metals of the anode.

Description

Die Erfindung betrifft Anoden für die elektrochemische Fluorierung und Fluorerzeugung sowie ein Verfahren zu deren Herstellung.The invention relates to anodes for electrochemical fluorination and fluorine generation and to a method for their production.

Die elektrochemische Fluorierung in wasserfreier bzw. wasserarmer kondensierter Fluorwasserstoffsäure ist insbesondere für organische Verbindungen ein technisch bedeutendes und im Vergleich zur Fluorierung mit elementarem Fluor sehr schonendes und selektives Verfahren.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.

Das entscheidende technische Problem bei diesem Verfahren liegt in der Korrosion oder auch Passivierung der Anode, die üblicherweise aus reinem Nickel hergestellt wird. Dadurch ist einmal die Standzeit der Anoden vor allem bei höheren Stromdichten recht kurz, zum anderen müssen aufgrund beträchtlicher Polarisationseffekte wesentlich höhere Spannungen angelegt werden, als man dies aufgrund der Thermodynamik der Fluorierungsreaktionen erwarten dürfte.The decisive technical problem with this method is the corrosion or passivation of the anode, which is usually made of pure nickel. As a result, 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.

Zahlreiche andere Metalle und deren Legierungen, die als Ersatz für Nickel als Anodenmaterial in wasserfreier Fluorwasserstoffsäure untersucht wurden, zeigten insbesondere in Bezug auf das Korrosionsverhalten noch schlechtere Ergebnisse. Auch Kohlenstoffmaterialien erwiesen sich wegen zerstörerischer Einlagerungsreaktionen und der Bildung von Graphitfluorid an ihrer Oberfläche als wenig geeignet (N. Hackermann, E.S. Snavely, L.D. Fiel, Corros. Sci., 7 (1967) 39; A.G. Doughty, M. Fleischmann, D. Pletcher, J. Electroanal. Chem., 51 (1974) 456).Numerous other metals and their alloys, which were investigated as a substitute for nickel as anode material in anhydrous hydrofluoric acid, showed even worse results, particularly with regard to the corrosion behavior. Carbon materials also proved to be unsuitable because of destructive intercalation reactions and the formation of graphite fluoride on their surface (N. Hackermann, ES Snavely, LD Fiel, Corros. Sci., 7 (1967) 39; AG Doughty, M. Fleischmann, D. Pletcher , J. Electroanal. Chem., 51 (1974) 456).

Die gegenüber anderen Metallanoden oder Graphitanoden relativ gute Stabilität von Nickelanoden in wasserfreier Fluorwasserstoffsäure ist technisch immer noch ungenügend.The relatively good stability of nickel anodes in anhydrous hydrofluoric acid compared to other metal anodes or graphite anodes is still technically insufficient.

Es hat nicht an Versuchen gefehlt, durch Oberflächenbehandlung der Nickelanoden ein weiter verbessertes Korrosions- und Überspannungsverhalten zu erreichen, Insbesondere die Fluorierung durch gasförmiges Fluor vor dem Einsatz in der Elektrolyse soll einen positiven Einfluß haben (J.N. Voitovic, V.J. Kasakov, J. Prikl. Chim., 44 (1971) 2452). Nachteilig an dieser Methode ist neben der Aufwendigkeit - vor allem bei der Fluorierung sehr großer Teile - die offenbar nur kurzzeitige Wirkung. In der Tat scheint es nahezu aussichtslos zu sein, eine Schutzschicht auf Nickel aufzubringen, die durch Langzeitstabilität gegen Fluorwasserstoffsäure und Fluor und obendrein auch noch durch eine genügende elektronische Leitfähigkeit ausgezeichnet ist.There has been no lack of attempts to achieve a further improved corrosion and overvoltage behavior by surface treatment of the nickel anodes, in particular fluorination by gaseous fluorine before use in electrolysis is said to have a positive influence (JN Voitovic, VJ Kasakov, J. Prikl. Chim ., 44 (1971) 2452). A disadvantage of this method is, in addition to the complexity - especially when fluorinating very large parts - the apparently only short-term effect. In fact, it seems almost hopeless to apply a protective layer on nickel, which is characterized by long-term stability against hydrofluoric acid and fluorine and, on top of that, also by sufficient electronic conductivity.

Aufgabe war es daher, möglichst korrosionsfeste Anoden für die Elektrolyse in Fluorwasserstoffsäure zur Verfügung zu stellen, wobei sich diese Anoden gegenüber den bisherigen Nickel-Anoden auch noch durch eine niedrigere für die Elektrolyse erforderliche Spannung auszeichnen sollen, Solche Elektroden würden bei der elektrochemischen Fluorierung aber auch bei der elektrochemischen Erzeugung von Fluor wirtschaftliche Vorteile bringen.It was therefore the task to provide corrosion-resistant anodes for the electrolysis in hydrofluoric acid, which anodes should also be distinguished by a lower voltage required for the electrolysis compared to the previous nickel anodes, but such electrodes would also be used in electrochemical fluorination bring economic benefits in the electrochemical production of fluorine.

Diese Aufgabe konnte mit den erfindungsgemäßen Anoden gelöst werden.This problem could be solved with the anodes according to the invention.

Gegenstand der Erfindung sind Metallanoden für die Elektrofluorierung oder für die elektrochemische Fluorerzeugung, die eine elektronenleitende oder zumindest halbleitende Schicht aus einer oder mehreren Verbindungen des der Anode zugrundeliegenden Metalles oder der Metalle aufweisen, auf der sich gegebenenfalls eine weitere Schicht aus einer oder mehreren Fluorverbindungen des der Anode zugrundeliegenden Metalles oder der Metalle befindet.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.

Bevorzugt als Metallverbindungen für die elektronen- oder zumindest halbleitende Schicht sind Oxide oder Sulfide des Metalls.Oxides or sulfides of the metal are preferred as metal compounds for the electron or at least semiconducting layer.

Als bevorzugte Metalle für die Anoden werden neben Ni auch Cu, Nb, Ta, V, Mo, W, Ti, Zr, Hf, Fe, La und Th oder deren Legierungen eingesetzt.In addition to Ni, preferred metals for the anodes are also Cu, Nb, Ta, V, Mo, W, Ti, Zr, Hf, Fe, La and Th or their alloys.

Ein weiterer Gegenstand der Erfindung ist ein Verfahren zur Herstellung der erfindungsgemäßen Metallanoden, welches dadurch gekennzeichnet ist, daß die den Anoden zugrundeliegenden Metalle an ihrer Oberfläche zur Erzeugung einer Schicht oxidiert werden und gegebenenfalls anschließend die oxidierten Metallanoden zur Erzeugung einer weiteren Schicht fluoriert werden, z.B. in Fluorwasserstoffsäure.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.

Die Oxidation wird vorzugsweise thermisch an Luft durchgeführt.The oxidation is preferably carried out thermally in air.

Bevorzugt findet die Oxidation für Nickelanoden bei Temperaturen über 800° C statt (zwischen 800 und 1300° C).The oxidation for nickel anodes preferably takes place at temperatures above 800 ° C. (between 800 and 1300 ° C.).

Die Fluorierung der oxidierten Metallelektroden zur Erzeugung der weiteren Schicht kann seperat vor dem eigentlichen Prozeß der Elektrofluorierung oder Fluorerzeugung durchgeführt werden oder aber auch während des Prozesses der Elektrofluorierung oder Fluorerzeugung.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.

Vorteil der erfindungsgemäßen Metallanoden ist, daß sie besonders korrosionsbeständig sind und zwar über einen längeren Zeitraum und daß sie eine höhere Stromdichte zulassen bzw. eine niedrigere Überspannung aufweisen.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.

Die Erfindung soll anhand der folgenden Beispiele näher erläutert werden, ohne daß darin eine Einschränkung zu sehen ist.The invention will be explained in more detail with the aid of the following examples, without any limitation being seen therein.

Beispiel 1example 1

Eine Elektrode aus reinem Nickel (Ni > 99.7) wird zwei Stunden an Luft bei 1200° C geglüht. Die Elektrode verfärbt sich hierbei durch Oxidbildung an der Oberfläche nach blauschwarz. Die Dicke der Oxidschicht liegt bei etwa 10 µm.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 µm.

Anschließend kann die Elektrode ohne weitere Behandlung als Anode in einer Lösung von 1 Mol/l KF in praktisch wasserfreier kondensierter Fluorwasserstoffsäure eingesetzt werden. Nach 21-stündiger Belastung mit 4.5 mA/cm² sind an der Elektrode mit bloßem Auge keine Korrosionsschäden zu erkennen, Die Elektrode ist praktisch unverändert glatt und blauschwarz sowie frei von Nickelfluorid-Verkrustungen. Das Lichtmikroskop zeigt bei 50-facher Vergrößerung nur vereinzelte minimale Ansätze von Korrosion bzw. Verfärbung.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.

Eine Vergleichselektrode aus nicht vorbehandeltem reinem Nickel ist nach identischer 21-stündiger Belastung mit Nickelfluorid verkrustet.A comparative electrode made of non-pretreated pure nickel is encrusted with nickel fluoride after an identical 21-hour exposure.

Beispiel 2Example 2

Eine Elektrode aus reinem Nickel wird wie in Beispiel 1 an Luft bei 1200° C geglüht, jedoch für eine Zeitdauer von 3 Stunden.An electrode made of pure nickel is annealed in air at 1200 ° C. as in Example 1, but for a period of 3 hours.

Anschließend werden Polarisationsmessungen während einer Konstantstrombelastung von 12.4 mA/cm² in einer Lösung von 1 Mol/l KF in praktisch wasserfreier kondonsierter Fluorwasserstoffsäure durchgeführt. Im Verlauf von 24 Betriebsstunden bleibt ihr Potential im Bereich von ca. 4.3 bis ca. 5.0 V gegen eine Wasserstoff-Elektrode in derselben Elektrolytlösung.Then polarization measurements are condensed during a constant current load of 12.4 mA / cm² in a solution of 1 mol / l KF in practically water-free Hydrofluoric acid performed. Over the course of 24 hours of operation, their potential remains in the range from approx. 4.3 to approx. 5.0 V against a hydrogen electrode in the same electrolyte solution.

An einer Vergleichselektrode aus nicht vorbehandeltem Nickel liegt das Potential bei sonst gleichen Bedingungen im Durchschnitt etwa 2 V höher, d.h., die Spannungsverluste bei der Elekrolyse sind um diesen Betrag höher.On a comparison electrode made of non-pretreated nickel, the potential is about 2 V higher on average under otherwise identical conditions, i.e. the voltage losses during electrolysis are higher by this amount.

Beispiel 3Example 3

Eine Elektrode aus reinem Nickel wird 2 Stunden unter Zufuhr von reinem Sauerstoff bei ca. 1200° C geglüht. Die sich bildende Oberflächenschicht aus Nickeloxid ist in diesem Fall grünlichschwarz. Sowohl beim Korrosionsverhalten als auch beim Polarisationsverhalten in einer Lösung von 1 Mol/l KF in Fluorwasserstoffsäure ergeben sich Vorteile gegenüber einer Vergleichselektrode aus reinem Nickel.An electrode made of pure nickel is annealed for 2 hours while adding pure oxygen at approx. 1200 ° C. In this case, the nickel oxide surface layer that forms is greenish black. Both the corrosion behavior and the polarization behavior in a solution of 1 mol / l KF in hydrofluoric acid have advantages over a comparison electrode made of pure nickel.

Beispiel 4Example 4

Eine Elektrode aus Reinnickel wird galvanisch mit einer ca. 5 µm dicken Schicht aus Kupfer überzogen. Anschließend wird für 2 Stunden an Luft auf 1200° C erhitzt.An electrode made of pure nickel is galvanically coated with an approx. 5 µm thick layer of copper. The mixture is then heated to 1200 ° C. in air for 2 hours.

Die Elektrode verfärbt sich bei dieser Behandlung nach blauschwarz. Als Anode in praktisch wasserfreier kondensierter Fluorwasserstoffsäure zeigt sie erheblich besseres Korrosions- und Polarisationsverhalten als eine Vergleichselektrode aus Reinnickel.During this treatment, the electrode turns blue-black. As an anode in practically water-free condensed hydrofluoric acid, it shows considerably better corrosion and polarization behavior than a comparative electrode made of pure nickel.

Claims (8)

Metallanoden für die Elektrofluorierung oder für die elektrochemische Fluorerzeugung, dadurch gekennzeichnet, daß die Metallanoden eine elektronenleitende oder zumindest halbleitende Schicht aus einer oder mehreren Verbindungen des der Anode zugrundeliegenden Metalles oder der Metalle, aus denen die Anode überwiegend besteht, aufweisen, auf der sich gegebenenfalls eine weitere Schicht aus Fluorverbindungen des Metalles oder der Metalle befindet.Metal anodes for electrofluorination or for electrochemical fluorine production, characterized in that the metal anodes have an electron-conducting or at least semiconducting layer made of one or more compounds of the metal on which the anode is based or of the metals from which the anode predominantly consists, on which there may be a another layer of fluorine compounds of the metal or metals is located. Metallanoden gemäß Anspruch 1, dadurch gekennzeichnet, daß die elektronenleitende oder zumindest halbleitende Schicht aus Oxiden oder Sulfiden des Metalles oder der Metalle besteht.Metal anodes according to claim 1, characterized in that the electron-conducting or at least semiconducting layer consists of oxides or sulfides of the metal or metals. Metallanoden gemäß Anspruch 1, dadurch gekennzeichnet, daß die Anoden aus Ni, Cu, V, Nb, Mo, W, Ti, Zr, Hf, Fe, La, Th oder deren Legierungen bestehen.Metal anodes according to claim 1, characterized in that the anodes consist of Ni, Cu, V, Nb, Mo, W, Ti, Zr, Hf, Fe, La, Th or their alloys. Metallanoden gemäß Anspruch 3, dadurch gekennzeichnet, daß die Metallanoden aus Nickel als Grundmetall bestehen.Metal anodes according to claim 3, characterized in that the metal anodes consist of nickel as the base metal. Verfahren zur Herstellung der Metallanoden gemäß einem der Ansprüche 1 bis 4, dadurch gekennzeichnet, daß die den Anoden zugrundeliegenden Metalle an ihrer Oberfläche zur Erzeugung einer leitenden oder zumindest halbleitenden Schicht oxidiert werden und daß gegebenenfalls anschließend die oxidierten Metallanoden zur Erzeugung einer weiteren Schicht fluoriert werden.Method for producing the metal anodes according to one of claims 1 to 4, characterized in that the metals on which the anodes are based are oxidized on their surface to produce a conductive or at least semiconductive layer and that the oxidized metal anodes are subsequently fluorinated if necessary to produce a further layer. Verfahren gemäß Anspruch 5, dadurch gekennzeichnet, daß die Oxidation thermisch mit Luft durchgeführt wird.A method according to claim 5, characterized in that the oxidation is carried out thermally with air. Verfahren gemäß Anspruch 5, dadurch gekennzeichnet, daß die Oxidation der Nickelanoden bei Temperaturen zwischen 800 und 1.300° C durchgeführt wird.Process according to claim 5, characterized in that the oxidation of the nickel anodes is carried out at temperatures between 800 and 1,300 ° C. Verfahren gemäß Anspruch 5 bis 7, dadurch gekennzeichnet, daß die Fluorierung der oxidierten Metallanoden seperat vor oder während des eigentlichen Prozesses der Elektrofluorierung oder der Fluorerzeugung durchgeführt wird.Process according to Claims 5 to 7, characterized in that the fluorination of the oxidized metal anodes is carried out separately before or during the actual process of electrofluorination or fluorine generation.
EP91104625A 1990-04-05 1991-03-23 Anodes for the electrochemical fluorination and fluorine production and their manufacturing process Withdrawn EP0451589A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4010961 1990-04-05
DE4010961A DE4010961A1 (en) 1990-04-05 1990-04-05 ANODES FOR ELECTROCHEMICAL FLUORATION AND FLUORINE PRODUCTION AND METHOD FOR THE PRODUCTION THEREOF

Publications (1)

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

Family

ID=6403793

Family Applications (1)

Application Number Title Priority Date Filing Date
EP91104625A Withdrawn EP0451589A1 (en) 1990-04-05 1991-03-23 Anodes for the electrochemical fluorination and fluorine production and their manufacturing process

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 (en) * 1992-08-13 1994-03-09 Bayer Ag A process for preparing perfluoroalkylsulfonylfluorides and electrodes for carrying out said process

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3340273B2 (en) * 1995-02-21 2002-11-05 三井化学株式会社 Composite electrode and method for producing nitrogen trifluoride gas using the same
KR100641603B1 (en) * 2003-09-04 2006-11-02 주식회사 소디프신소재 Preparation of high purity fluorine gas

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 (en) * 1977-06-03 1978-12-14 Bayer Ag Per:fluoroalkane-sulphonyl fluoride prepn. - by electrolysis of alkane-sulphonyl halide or sulphone in hydrogen fluoride

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2300422C3 (en) * 1973-01-05 1981-10-15 Hoechst Ag, 6000 Frankfurt Method of making an electrode
JPS5573884A (en) * 1978-11-24 1980-06-03 Asahi Chem Ind Co Ltd Preparation of electrode
DE2903407C2 (en) * 1979-01-30 1983-12-15 BOMIN Bochumer Mineralöl GmbH & Co, 4630 Bochum Use of a porous electrode hot-pressed or sintered from nickel powder
IT1127303B (en) * 1979-12-20 1986-05-21 Oronzio De Nora Impianti PROCEDURE FOR THE PREPARATION OF MIXED CATALYTIC OXIDES
DE3737235A1 (en) * 1987-11-03 1989-06-01 Heiner Dr Ing Debrodt Method for manufacturing an anode for electrochemical processes

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 (en) * 1977-06-03 1978-12-14 Bayer Ag Per:fluoroalkane-sulphonyl fluoride prepn. - by electrolysis of alkane-sulphonyl halide or sulphone in hydrogen fluoride

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0585627A1 (en) * 1992-08-13 1994-03-09 Bayer Ag A process for preparing perfluoroalkylsulfonylfluorides and electrodes for carrying out said process
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
JPH05140783A (en) 1993-06-08
DE4010961C2 (en) 1993-01-07
DE4010961A1 (en) 1991-10-10

Similar Documents

Publication Publication Date Title
DE1814576C2 (en) Electrode for use in electrolytic processes and methods for their manufacture
DE2636447C2 (en) Manganese dioxide electrodes
DE2300422C3 (en) Method of making an electrode
DE3018563C2 (en) Corrosion-resistant electrodes for the electrolysis of aqueous solutions of alkali halides
DE3219003C2 (en)
DE2403573A1 (en) NEW ELECTRODES AND METHODS FOR MAKING THEM
DE1571721B2 (en) ELECTRODE FOR USE IN ELECTROLYTIC PROCESSES
DE1796220B2 (en) Method of making an electrode for use in electrolytic processes
DE2113676C2 (en) Electrode for electrochemical processes
DE3047636A1 (en) CATHODE, METHOD FOR THE PRODUCTION THEREOF, THEIR USE AND ELECTROLYSIS CELL
DE2909593C2 (en)
DE2201015C2 (en) Process for the manufacture of a lead dioxide electrode
DE2338549B2 (en)
EP0451589A1 (en) Anodes for the electrochemical fluorination and fluorine production and their manufacturing process
DE2710802C3 (en) Process for the production of electrodes for electrolytic cells
DE1909757B2 (en) PROCESS FOR THE CLEANING OF ANODES FOR ELECTROLYTIC PROCESSES, THAT CONSIST OF A BACKING OF A FILM-FORMING METAL AND A COATING OF PRECIOUS METALS, PRECIOUS METALLOIDS OR PRECIOUS METAL OXIDES CONTAINING MIXED OXIDES
DE2844558A1 (en) ELECTRODE FOR USE IN AN ELECTROLYTIC METHOD
DE3443338C2 (en) Cathode for the production of electrolyte manganese dioxide
DE2032645A1 (en) Process for the production of diffusion coatings from tantalum or niobium on metals or metal alloys
DE2638218B1 (en) METHOD OF MANUFACTURING ELECTRODES
DE60121337T2 (en) METHOD FOR IMPROVING AN ELECTRODE
DE3032480C2 (en) Process for removing electrocatalytically effective protective coatings from electrodes with a metal core and application of the process
EP0911428B1 (en) Process for producing bismuth compounds
DE2044260A1 (en) electrode
DE3432652C2 (en)

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): BE DE FR GB IT

17P Request for examination filed

Effective date: 19911104

17Q First examination report despatched

Effective date: 19930712

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19930906