EP0308838B1 - Process for the production of fluorinated acrylic acids and their derivatives - Google Patents
Process for the production of fluorinated acrylic acids and their derivatives Download PDFInfo
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- EP0308838B1 EP0308838B1 EP88115288A EP88115288A EP0308838B1 EP 0308838 B1 EP0308838 B1 EP 0308838B1 EP 88115288 A EP88115288 A EP 88115288A EP 88115288 A EP88115288 A EP 88115288A EP 0308838 B1 EP0308838 B1 EP 0308838B1
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- 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
- C25B3/25—Reduction
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- 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
- C25B15/00—Operating or servicing cells
- C25B15/02—Process control or regulation
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- 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 an electrochemical process for the production of fluorinated acrylic acids and their derivatives by selective dehalogenation of halogen-containing fluoropropionic acids and their derivatives.
- Acrylic acid and methacrylic acid derivatives have a very wide range of applications as organic intermediates. They allow access to a large number of useful compounds, but they are particularly suitable for the production of plastics.
- Halogenated and deuterated acrylic and methacrylic acid derivatives have been of particular interest for some time, since such substances are suitable for the production of special plastics with special properties.
- ⁇ -Haloacrylic acid ester used for the production of radiation-sensitive protective layers in resist technology.
- ⁇ -fluoroacrylic acid esters are suitable, for example, for the production of plastic glasses for aviation technology and are also suitable starting materials for polymer optical fibers, with deuterated derivatives being of particular interest owing to their better optical properties.
- halogenated fluorine-containing acrylic acid derivatives can be prepared by dehalogenation of correspondingly halogenated fluoropropionic acid derivatives.
- the most common methods of eliminating two vicinal halogen atoms in halogen propionic acids to form a double bond use metals as dehalogenating agents, with zinc, which is used in various forms and activities, being of the greatest importance. Frequently, however, the reactions with zinc are so slow that one is forced to work in higher boiling solvents such as dimethylformamide or in diphenyl ether in the presence of thiourea.
- An additional disadvantage, especially for technical implementation, is that the use of metals as a dehalogenating reagent inevitably involves the accumulation of metal salts.
- Electrochemical dehalogenation is one way of avoiding the formation of metal salts during dehalogenation.
- the previous efforts to simultaneously electrochemically split off two vicinal halogen atoms from halogenated propionic acids have mainly been of an analytical nature and have been carried out, for example, using polarographic or cyclic voltammetric methods on mercury electrodes or glassy carbon electrodes (J. Am. Chem. Soc. 80 , 5402 (1959); J. Chem. Research (M) 1983, 2401).
- M J. Chem. Research
- the object was therefore to provide a technically feasible and economical process according to which halogen atoms can be split off from fluorine-containing halogen propionic acids or their derivatives by electrochemical means to form fluorine-containing acrylic acids without losses due to polymerization or saturation of the acrylic acid double bond and without so that a forced attack of metal halides is associated.
- this object can be achieved by electrochemical dehalogenation under galvanostatic conditions in water, optionally in the presence of an auxiliary solvent and / or a salt a metal with a hydrogen overvoltage of more than 0.25V is carried out.
- Perhalogenated propionic acids such as 2,3-dichloro-2,3,3-trifluoropropionic acid, 2,3-dibromo-2,3,3-trifluoropropionic acid, 2-bromo-3-chloro-2,3,3-trifluoropropionic acid, 3-bromo -2-chloro-2,3,3-trifluoropropionic acid, 2,3,3-trichloro-2,3-difluoropropionic acid, 2,2,3-trichloro-3,3-difluoropropionic acid and 2,3,3,3-tetrachloro -2-fluoropropionic acid, preferably 2,3-dibromo-2,3,3-trifluoropropionic acid, 2,3,3-trichloro-2,3-difluoropropionic acid and 2,3,3,3-tetrachloro-2-fluoropropionic acid, preferably 2,3-dibromo-2,3,3-trifluoropropi
- the method according to the invention is carried out in divided or undivided cells.
- the common diaphragms made of polymers, preferably perfluorinated polymers, or other organic or inorganic materials, such as glass or ceramics, but preferably ion exchange membranes, are used to divide the cells into anode and cathode spaces.
- Preferred ion exchange membranes are cation exchange membranes from polymers, preferably perfluorinated polymers with carboxyl and / or sulfonic acid groups. The use of stable anion exchange membranes is also possible.
- the electrolysis can be carried out in all customary electrolysis cells, for example in beaker or plate and frame cells or cells with fixed bed or fluidized bed electrodes. Both the monopolar and the bipolar switching of the electrodes can be used.
- a method of operation in divided electrolysis cells with discontinuous execution of the cathode reaction and continuous operation of the anode reaction is particularly expedient.
- the electrolysis can be carried out on all cathodes stable in the electrolyte.
- Materials with a medium to high hydrogen overvoltage such as Pb, Cd, Zn, carbon, Cu, Sn, Zr and mercury compounds such as copper amalgam, lead malgam etc. are particularly suitable, but also alloys such as e.g. Lead-tin or zinc-cadmium.
- the use of carbon cathodes is preferred, especially for electrolysis in acidic electrolytes, since some of the electrode materials listed above, e.g. Zn, Sn, Cd and Pb, can suffer corrosion.
- all possible carbon electrode materials come into question as carbon cathodes, e.g. Electrode graphites, impregnated graphite materials, carbon felts and also glassy carbon.
- All materials on which the known anode reactions take place can be used as the anode material.
- Examples are lead, lead oxide on lead or other carriers, platinum or with noble metal oxides, eg platinum oxide, doped titanium dioxide on titanium or other materials for the development of oxygen from dilute sulfuric acid or carbon or titanium dioxide doped with noble metal oxides on titanium or other materials for the development of chlorine from aqueous alkali metal chloride or aqueous or alcoholic hydrogen chloride Solutions.
- Preferred anolyte liquids are aqueous mineral acids or solutions of their salts, such as, for example, dilute sulfuric acid, concentrated hydrochloric acid, sodium sulfate or sodium chloride solutions and solutions of hydrogen chloride in alcohol.
- the electrolyte in the undivided cell or the catholyte in the divided cell contains 0 to 100% water and 100 to 0% of one or more organic solvents.
- suitable solvents are: Short-chain, aliphatic alcohols such as methanol, ethanol, propanol or butanol, diols such as ethylene glycol, propanediol but also polyethylene glycols and their ethers, ethers such as tetrahydrofuran, dioxane, amides such as N, N-dimethylformamide, hexamethylphosphoric triamide, N-methyl-2-pyrrolidone, Nitriles such as acetonitrile, propionitrile, ketones such as acetone, and other solvents such as dimethyl sulfoxide and sulfolane.
- suitable solvents are: Short-chain, aliphatic alcohols such as methanol, ethanol, propanol or butanol, diols such as ethylene glycol, propanediol but also polyethylene glycols and their ethers, ethers such as tetrahydrofuran, dioxane, amides such
- the electrolyte can also consist of water and a water-insoluble organic solvent such as t-butyl methyl ether or methylene chloride in conjunction with a phase transfer catalyst.
- a water-insoluble organic solvent such as t-butyl methyl ether or methylene chloride in conjunction with a phase transfer catalyst.
- inorganic or organic acids can be added to the catholyte in the divided cell or to the electrolyte in the undivided cell, preferably Acids such as hydrochloric, boric, phosphoric, sulfuric or tetrafluoroboric acid and / or formic, acetic or citric acid and / or their salts.
- organic bases may also be necessary to set the pH value which is favorable for the electrolysis and / or have a favorable influence on the course of the electrolysis.
- Suitable are primary, secondary or tertiary C2-C12 alkyl or cycloalkylamines, aromatic or aliphatic-aromatic amines or their salts, inorganic bases such as alkali or alkaline earth metal hydroxides such as Li, Na, K, Cs, Mg, Ca, Ba hydroxide, quaternary ammonium salts, with anions such as fluorides, chlorides, bromides, iodides, acetates, sulfates, hydrogen sulfates, tetrafluoroborates, phosphates or hydroxides, and with cations such as C1-C12-tetraalkylammonium, C1-C12 -Trialkylarylammonium or C1-C12-trialkylalkylarylammonium, but also anionic or
- compounds can be added to the electrolyte which are oxidized at a more negative potential than the released halogen ions in order to avoid the formation of the free halogen.
- the salts of oxalic acid, methoxyacetic acid, glyoxylic acid, formic acid and / or hydrochloric acid are suitable.
- the electrolyte in the undivided cell or the catholyte in the divided cell can be salts of Metals with a hydrogen overvoltage of at least 0.25 V (based on a current density of 300 mA / cm2) and / or dehalogenating properties can be added.
- the most suitable salts are the soluble salts of Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Tl, Ti, Zr, Bi, V, Ta, Cr or Ni, preferably the soluble Pb, Zn, Cd, Ag and Cr salts.
- the preferred anions of these salts are Cl ⁇ , SO4 ⁇ , NO3 ⁇ , and CH3COO ⁇ .
- the salts can be added directly to the electrolysis solution or, e.g. by adding oxides, carbonates etc. - in some cases also the metals themselves (if soluble) - in the solution.
- Electrolysis is carried out at a current density of 1 to 600 mA / cm2, preferably at 10 to 500 mA / cm2, without potential control.
- the electrolysis temperature is in the range from -10 ° C to the boiling point of the electrolyte liquid, preferably from 10 ° to 90 ° C, in particular from 15 ° to 80 ° C.
- the electrolysis product is worked up in a known manner, e.g. by extracting or distilling off the solvent.
- the compounds added to the catholyte can thus be returned to the process.
- Electrolysis cell 1
- Anolyte dilute aqueous sulfuric acid or methanolic hydrochloric acid
- Cation exchange membrane single-layer membrane made from a copolymer of a perfluorosulfonylethoxy vinyl ether and tetrafluoroethylene Mass transfer: by magnetic stirrer
- Electrolytic cell 2
- Jacketed glass pot circulation cell with a volume of 450 cm3 Anode: platinum mesh, graphite or lead plate (20 cm2) Cathode area: 12 cm2 Electrode distance: 1 cm Anolyte: dilute aqueous sulfuric acid or methanolic hydrochloric acid Cation exchange membrane as in electrolysis cell 1 Current density: 83 mA / cm2 Terminal voltage: 5 V
- Electrolysis cell 1
- Electrolysis cell 1
- CCl3-CFCl-COOH 0.428 g
- CCl2 CF-COOH 0.206 g
- CHCl CF-COOH 0.204 g
Abstract
Description
Die Erfindung bezieht sich auf ein elektrochemisches Verfahren zur Herstellung von fluorierten Acrylsäuren und ihren Derivaten durch selektive Enthalogenierung von halogenhaltigen Fluorpropionsäuren und ihren Derivaten.The invention relates to an electrochemical process for the production of fluorinated acrylic acids and their derivatives by selective dehalogenation of halogen-containing fluoropropionic acids and their derivatives.
Acrylsäure- und Methacrylsäurederivate besitzen ein sehr breites Anwendungsfeld als organische Zwischenprodukte. Sie gestatten den Zugang zu einer Vielzahl nützlicher Verbindungen, vor allem eignen sie sich jedoch zur Herstellung von Kunststoffen.Acrylic acid and methacrylic acid derivatives have a very wide range of applications as organic intermediates. They allow access to a large number of useful compounds, but they are particularly suitable for the production of plastics.
Seit einiger Zeit finden halogenierte und deuterierte Acryl- und Methacrylsäurederivate besonderes Interesse, da solche Stoffe sich zur Herstellung von speziellen Kunststoffen mit besonderen Eigenschaften eignen.Halogenated and deuterated acrylic and methacrylic acid derivatives have been of particular interest for some time, since such substances are suitable for the production of special plastics with special properties.
So werden z.B. α-Halogenacrylsäureester für die Herstellung von strahlungsempfindlichen Schutzschichten in der Resisttechnik verwendet. Speziell α-Fluoracrylsäureester eignen sich beispielsweise zur Herstellung von Kunststoffgläsern für die Luftfahrttechnik und stellen außerdem geeignete Ausgangsmaterialien für polymere Lichtwellenleiter dar, wobei deuterierte Derivate aufgrund ihrer besseren optischen Eigenschaften besonderes Interesse finden.For example, α-Haloacrylic acid ester used for the production of radiation-sensitive protective layers in resist technology. In particular, α-fluoroacrylic acid esters are suitable, for example, for the production of plastic glasses for aviation technology and are also suitable starting materials for polymer optical fibers, with deuterated derivatives being of particular interest owing to their better optical properties.
Es ist vorgeschlagen worden,zur Herstellung von fluorierten Acrylsäurederivaten, insbesondere auch von entsprechend deuterierten Verbindungen, halogenierte fluorhaltige Acrylsäurederivate als Ausgangsverbindungen zu verwenden (vgl. DE-A-37 04 915).It has been proposed to use halogenated fluorine-containing acrylic acid derivatives as starting compounds for the preparation of fluorinated acrylic acid derivatives, in particular also of correspondingly deuterated compounds (cf. DE-A-37 04 915).
Es ist weiterhin bekannt, daß man halogenierte fluorhaltige Acrylsäurederivate durch Enthalogenierung von entsprechend halogenierten Fluorpropionsäurederivaten herstellen kann. Die gebräuchlichsten Methoden, in Halogenpropionsäuren zwei vicinale Halogenatome unter Ausbildung einer Doppelbindung zu eliminieren, verwenden Metalle als Enthalogenierungsmittel, wobei dem Zink, welches in unterschiedlichen Formen und Aktivitäten eingesetzt wird, die größte Bedeutung zukommt. Häufig verlaufen die Reaktionen mit Zink jedoch so langsam, daß man gezwungen ist, in höher siedenden Lösungsmitteln wie Dimethylformamid oder in Diphenylether in Gegenwart von Thioharnstoff zu arbeiten. Zusätzlich von Nachteil ist, vor allem für die technische Realisierung, daß mit der Verwendung von Metallen als Enthalogenierungsreagenz zwangsweise ein Anfall von Metallsalzen verbunden ist.It is also known that halogenated fluorine-containing acrylic acid derivatives can be prepared by dehalogenation of correspondingly halogenated fluoropropionic acid derivatives. The most common methods of eliminating two vicinal halogen atoms in halogen propionic acids to form a double bond use metals as dehalogenating agents, with zinc, which is used in various forms and activities, being of the greatest importance. Frequently, however, the reactions with zinc are so slow that one is forced to work in higher boiling solvents such as dimethylformamide or in diphenyl ether in the presence of thiourea. An additional disadvantage, especially for technical implementation, is that the use of metals as a dehalogenating reagent inevitably involves the accumulation of metal salts.
Auch Enthalogenierungsmethoden mit Natriumsulfid in Dimethylformamid an Dibrompropionsäure haben einen Zwangsanfall von Salzen zur Folge.Dehalogenation methods with sodium sulfide in dimethylformamide on dibromopropionic acid also lead to the inevitable formation of salts.
Eine Möglichkeit, die Bildung von Metallsalzen bei einer Enthalogenierung zu umgehen, bietet die elektrochemische Enthalogenierung. Jedoch waren die bisherigen Bemühungen, gleichzeitig zwei vicinale Halogenatome aus halogenierten Propionsäuren elektrochemisch abzuspalten, hauptsächlich analytischer Natur und wurden z.B. mit Hilfe polarographischer oder cyclovoltammetrischer Methoden an Quecksilberelektroden bzw. Glaskohlenstoffelektroden durchgeführt (J. Am. Chem. Soc. 80, 5402 (1959); J.Chem. Research (M) 1983, 2401). Hierbei wurde lediglich aus der Kurvenform oder dem Ladungsverbrauch auf die Entstehung ungesättigter Produkte geschlossen oder es wurde eine offensichtliche Bildung niedermolekularer Polymerisationsprodukte auf die zwischenzeitliche Entstehung ungesättigter Verbindung zurückgeführt.Electrochemical dehalogenation is one way of avoiding the formation of metal salts during dehalogenation. However, the previous efforts to simultaneously electrochemically split off two vicinal halogen atoms from halogenated propionic acids have mainly been of an analytical nature and have been carried out, for example, using polarographic or cyclic voltammetric methods on mercury electrodes or glassy carbon electrodes (J. Am. Chem. Soc. 80 , 5402 (1959); J. Chem. Research (M) 1983, 2401). In this case, only the formation of unsaturated products was inferred from the curve shape or the charge consumption, or an obvious formation of low molecular weight polymerization products was attributed to the interim formation of unsaturated compounds.
Die wenigen präparativen Elektrolysen, die bisher bekannt geworden sind, wurden unter Potentialkontrolle an einer Quecksilberkathode durchgeführt und lieferten neben ungesättigten Verbindungen beachtliche Anteile an hydrierten und polymerisierten Produkten (J.Chem.Research (M) 1983, 2401).The few preparative electrolyses that have become known so far were carried out under potential control on a mercury cathode and, in addition to unsaturated compounds, provided considerable proportions of hydrogenated and polymerized products (J.Chem.Research (M) 1983, 2401).
Es war also bisher nicht möglich, halogenierte Propionsäurederivate elektrochemisch in Acrylsäurederivate zu überführen, ohne deutliche Verluste durch Hydrierung der Doppelbindung und Polymerisation in Kauf nehmen zu müssen. Außerdem sind die bisher beschriebenen Methoden, wie die Anwendung der Potentialkontrolle während der Elektrolyse oder die Verwendung von Quecksilber als Elektrodenmaterial, für eine technische Nutzung aus wirtschaftlichen bzw. physikalischen und toxikologischen Gesichtspunkten nicht geeignet. Weiterhin wurden auch insofern unbefriedigende Elektrolyseergebnisse erzielt, daß nur ein unvollständiger Umsatz erreicht wurde und neben großen Mengen hydrierter Produkte auch noch weitere, unbekannte Produkte gebildet wurden.So far it has not been possible to electrochemically convert halogenated propionic acid derivatives into acrylic acid derivatives without having to accept significant losses due to hydrogenation of the double bond and polymerization. In addition, the methods described so far, such as the use of potential control during electrolysis or the use of mercury as electrode material, are not suitable for technical use from an economic, physical and toxicological point of view. Furthermore, unsatisfactory electrolysis results were achieved in that only incomplete conversion was achieved and, in addition to large amounts of hydrogenated products, other, unknown products were formed.
Die Aufgabe bestand daher in der Bereitstellung eines technisch durchführbaren und wirtschaftlichen Verfahrens, nach dem aus fluorhaltigen Halogenpropionsäuren bzw. deren Derivaten auf elektrochemischem Wege Halogenatome unter Bildung fluorhaltiger Acrylsäuren abgespalten werden können, ohne daß Verluste durch Polymerisation oder Sättigung der Acrylsäure-Doppelbindung auftreten und ohne daß damit ein Zwangsanfall an Metallhalogeniden verbunden ist.The object was therefore to provide a technically feasible and economical process according to which halogen atoms can be split off from fluorine-containing halogen propionic acids or their derivatives by electrochemical means to form fluorine-containing acrylic acids without losses due to polymerization or saturation of the acrylic acid double bond and without so that a forced attack of metal halides is associated.
Es wurde gefunden, daß diese Aufgabe gelöst werden kann, indem die elektrochemische Enthalogenierung unter galvanostatischen Bedingungen in Wasser, gegebenenfalls in Gegenwart eines Hilfslösemittels und/oder eines Salzes eines Metalls mit einer Wasserstoffüberspannung von mehr als 0,25V durchgeführt wird.It has been found that this object can be achieved by electrochemical dehalogenation under galvanostatic conditions in water, optionally in the presence of an auxiliary solvent and / or a salt a metal with a hydrogen overvoltage of more than 0.25V is carried out.
Die Erfindung betrifft somit das in Ansprüchen beschriebene Verfahren.The invention thus relates to the method described in claims.
Im erfindungsgemäßen Verfahren werden fluorhaltige Verbindungen der Formel II
einer elektrolytischen Reduktion unterworfen, wobei fluorhaltige Verbindungen der Formel I entstehen. In diesen Formeln bedeuten
- R¹
- ein Fluoratom, eine Methyl- oder eine Deuteromethylgruppe, vorzugsweise ein Fluoratom,
- R²
- und R³ sind gleich oder verschieden und bedeuten ein Fluor-, Chlor-, Brom- oder Jodatom oder ein Wasserstoff-oder ein Deuteriumatom,
- R⁴
- bedeutet eine Cyanogruppe oder die Gruppe wobei
- R⁵
- -OH, -OD,-OMe mit Me = Alkali-, Erdalkali- oder NH₄⁺-Ion, C₁-C₁₂-Alkoxy, vorzugsweise C₁-C₆-Alkoxy, oder -NR⁶R⁷ ist, worin R⁶ und R⁷ gleich oder verschieden sind und H, D, C₁-C₁₂-Alkyl, vorzugsweise C₁-C₆-Alkyl, oder Phenyl bedeuten. Vorzugsweise ist R⁵ -OH, -OD oder -OMe mit Me = Alkali- oder NH₄⁺-Ion, oder C₁-C₆-Alkoxy, insbesondere -OH, - OD oder C₁-C₆-Alkoxy,
- R⁸ und R⁹
- sind gleich oder verschieden und bedeuten ein Chlor-, Brom- oder Jodatom,
subjected to an electrolytic reduction, whereby fluorine-containing compounds of the formula I are formed. Mean in these formulas
- R¹
- a fluorine atom, a methyl or a deuteromethyl group, preferably a fluorine atom,
- R²
- and R³ are identical or different and represent a fluorine, chlorine, bromine or iodine atom or a hydrogen or a deuterium atom,
- R⁴
- means a cyano group or the group wherein
- R⁵
- -OH, -OD, -OMe with Me = alkali, alkaline earth or NH₄⁺ ion, C₁-C₁₂ alkoxy, preferably C₁-C₆ alkoxy, or -NR⁶R⁷, wherein R worin and R⁷ are the same or different and H , D, C₁-C₁₂-alkyl, preferably C₁-C₆-alkyl, or phenyl. Preferably R⁵ is -OH, -OD or -OMe with Me = alkali or NH₄⁺ ion, or C₁-C₆-alkoxy, especially -OH, - OD or C₁-C₆-alkoxy,
- R⁸ and R⁹
- are identical or different and represent a chlorine, bromine or iodine atom,
Als Ausgangssubstanzen geeignet sind unter anderem folgende Verbindungen sowie ihre Ester, Amide, Nitrile and Salze:
Perhalogenierte Propionsäuren wie 2,3-Dichlor-2,3,3-trifluorpropionsäure, 2,3-Dibrom-2,3,3-trifluorpropionsäure, 2-Brom-3-chlor-2,3,3-trifluorpropionsäure, 3-Brom-2-chlor-2,3,3-trifluorpropionsäure, 2,3,3-Trichlor-2,3-difluorpropionsäure, 2,2,3-Trichlor-3,3-difluorpropionsäure und 2,3,3,3-Tetrachlor-2-fluorpropionsäure, vorzugsweise 2,3-Dibrom-2,3,3-trifluorpropionsäure, 2,3,3-Trichlor-2,3-difluor-propionsäure und 2,3,3,3-Tetrachlor-2-fluorpropionsäure, insbesondere 2,3,3,3-Tetrachlor-2-fluorpropionsäure;
teilhalogenierte Propionsäuren sowie deren deuterierte Analoga wie 2,3-Dibrom-2,3-difluorpropionsäure, 2,3-Dibrom-3,3-difluorpropionsäure, 2,3,3-Trichlor-2-fluorpropionsäure, 3-Brom-2,3-dichlor-2-fluorpropionsäure, 2-Brom-2,3-dichlor-3-fluorpropionsäure, 2,3,3-Trichlor-3-fluorpropionsäure, 2,3-Dibrom-2-fluorpropionsäure, 2,3-Dichlor-2-fluorpropionsäure und 3-Brom-2-chlor-2-fluorpropionsäure, vorzugsweise 2,3-Dibrom-2,3-difluorpropionsäure und 2,3-Dibrom-2-fluorpropionsäure;
halogenierte 2-Methylpropionsäuren wie 2,3-Dichlor-3,3-difluor-2-methylpropionsäure und 2-Brom-3-chlor-3-fluor-2-methylpropionsäure.The following compounds and their esters, amides, nitriles and salts are suitable as starting substances:
Perhalogenated propionic acids such as 2,3-dichloro-2,3,3-trifluoropropionic acid, 2,3-dibromo-2,3,3-trifluoropropionic acid, 2-bromo-3-chloro-2,3,3-trifluoropropionic acid, 3-bromo -2-chloro-2,3,3-trifluoropropionic acid, 2,3,3-trichloro-2,3-difluoropropionic acid, 2,2,3-trichloro-3,3-difluoropropionic acid and 2,3,3,3-tetrachloro -2-fluoropropionic acid, preferably 2,3-dibromo-2,3,3-trifluoropropionic acid, 2,3,3-trichloro-2,3-difluoropropionic acid and 2,3,3,3-tetrachloro-2-fluoropropionic acid, in particular 2,3,3,3-tetrachloro-2-fluoropropionic acid;
partially halogenated propionic acids and their deuterated analogues such as 2,3-dibromo-2,3-difluoropropionic acid, 2,3-dibromo-3,3-difluoropropionic acid, 2,3,3-trichloro-2-fluoropropionic acid, 3-bromo-2,3 -dichlor-2-fluoropropionic acid, 2-bromo-2,3-dichloro-3-fluoropropionic acid, 2,3,3-trichloro-3-fluoropropionic acid, 2,3-dibromo-2-fluoropropionic acid, 2,3-dichloro-2 -fluoropropionic acid and 3-bromo-2-chloro-2-fluoropropionic acid, preferably 2,3-dibromo-2,3-difluoropropionic acid and 2,3-dibromo-2-fluoropropionic acid;
halogenated 2-methylpropionic acids such as 2,3-dichloro-3,3-difluoro-2-methylpropionic acid and 2-bromo-3-chloro-3-fluoro-2-methylpropionic acid.
Das erfindungsgemäße Verfahren wird in geteilten oder ungeteilten Zellen durchgeführt. Zur Teilung der Zellen in Anoden- und Kathodenraum werden die üblichen im Elektrolyten stabilen Diaphragmen aus Polymeren, vorzugsweise perfluorierten Polymeren, oder anderen organischen oder anorganischen Werkstoffen, wie beispielsweise Glas oder Keramik, vorzugsweise aber Ionenaustauschermembranen, verwendet. Bevorzugte Ionenaustauschermembranen sind Kationenaustauschermembranen aus Polymeren, vorzugsweise perfluorierten Polymeren mit Carboxyl- und/oder Sulfonsäuregruppen. Die Verwendung von stabilen Anionenaustauschermembranen ist ebenfalls möglich.The method according to the invention is carried out in divided or undivided cells. The common diaphragms made of polymers, preferably perfluorinated polymers, or other organic or inorganic materials, such as glass or ceramics, but preferably ion exchange membranes, are used to divide the cells into anode and cathode spaces. Preferred ion exchange membranes are cation exchange membranes from polymers, preferably perfluorinated polymers with carboxyl and / or sulfonic acid groups. The use of stable anion exchange membranes is also possible.
Die Elektrolyse kann in allen üblichen Elektrolysezellen, wie beispielsweise in Becherglas- oder Platten- und Rahmenzellen oder Zellen mit Festbett- oder Fließbettelektroden, durchgeführt werden. Es ist sowohl die monopolare als auch die bipolare Schaltung der Elektroden anwendbar.The electrolysis can be carried out in all customary electrolysis cells, for example in beaker or plate and frame cells or cells with fixed bed or fluidized bed electrodes. Both the monopolar and the bipolar switching of the electrodes can be used.
Es ist möglich, die Elektrolyse sowohl kontinuerlich als auch diskontinuerlich durchzuführen. Besonders zweckmäßig ist eine Arbeitsweise in geteilten Elektrolysezellen mit diskontinuierlicher Ausführung der Kathodenreaktion und kontinuierlichem Betrieb der Anodenreaktion.It is possible to carry out the electrolysis both continuously and discontinuously. A method of operation in divided electrolysis cells with discontinuous execution of the cathode reaction and continuous operation of the anode reaction is particularly expedient.
Die Elektrolyse kann an allen im Elektrolyten stabilen Kathoden durchgeführt werden. In Frage kommen insbesondere Materialien mit einer mittleren bis hohen Wasserstoffüberspannung wie beispielsweise Pb, Cd, Zn, Kohlenstoff, Cu, Sn, Zr und Quecksilberverbindungen wie Kupferamalgam, Bleimalgam usw., aber auch Legierungen wie z.B. Blei-Zinn oder Zink-Cadmium. Bevorzugt ist die Verwendung von Kohlenstoffkathoden, insbesondere bei der Elektrolyse in saurem Elektrolyten, da einige der oben aufgeführten Elektrodenmaterialien, z.B. Zn, Sn, Cd und Pb, Korrosion erleiden können. Als Kohlenstoffkathoden kommen im Prinzip alle möglichen Kohle-Elektrodenmaterialien in Frage, wie z.B. Elektrodengraphite, imprägnierte Graphitwerkstoffe, Kohlefilze und auch glasartiger Kohlenstoff.The electrolysis can be carried out on all cathodes stable in the electrolyte. Materials with a medium to high hydrogen overvoltage such as Pb, Cd, Zn, carbon, Cu, Sn, Zr and mercury compounds such as copper amalgam, lead malgam etc. are particularly suitable, but also alloys such as e.g. Lead-tin or zinc-cadmium. The use of carbon cathodes is preferred, especially for electrolysis in acidic electrolytes, since some of the electrode materials listed above, e.g. Zn, Sn, Cd and Pb, can suffer corrosion. In principle, all possible carbon electrode materials come into question as carbon cathodes, e.g. Electrode graphites, impregnated graphite materials, carbon felts and also glassy carbon.
Als Anodenmaterial können alle Materialien verwendet werden, an denen die an sich bekannten Anodenreaktionen ablaufen. Beispiele sind Blei, Bleioxid auf Blei oder anderen Trägern, Platin oder mit Edelmetalloxiden,z.B. Platinoxid,dotiertes Titandioxid auf Titan oder anderen Materialien für die Sauerstoffentwicklung aus verdünnter Schwefelsäure oder Kohlenstoff oder mit Edelmetalloxiden dotiertes Titandioxid auf Titan oder anderen Materialien zur Entwicklung von Chlor aus wäßrigen Alkalichlorid-oder wäßrigen oder alkoholischen Chlorwasserstoff-Lösungen.All materials on which the known anode reactions take place can be used as the anode material. Examples are lead, lead oxide on lead or other carriers, platinum or with noble metal oxides, eg platinum oxide, doped titanium dioxide on titanium or other materials for the development of oxygen from dilute sulfuric acid or carbon or titanium dioxide doped with noble metal oxides on titanium or other materials for the development of chlorine from aqueous alkali metal chloride or aqueous or alcoholic hydrogen chloride Solutions.
Bevorzugte Anolytflüssigkeiten sind wäßrige Mineralsäuren oder Lösungen ihrer Salze, wie beispielsweise verdünnte Schwefelsäure, konzentrierte Salzsäure, Natriumsulfat- oder Natriumchloridlösungen und Lösungen von Chlorwasserstoff in Alkohol.Preferred anolyte liquids are aqueous mineral acids or solutions of their salts, such as, for example, dilute sulfuric acid, concentrated hydrochloric acid, sodium sulfate or sodium chloride solutions and solutions of hydrogen chloride in alcohol.
Der Elektrolyt in der ungeteilten Zelle oder der Katholyt in der geteilten Zelle enthält 0 bis 100 % Wasser und 100 bis 0 % eines oder mehrerer organischer Lösemittel.The electrolyte in the undivided cell or the catholyte in the divided cell contains 0 to 100% water and 100 to 0% of one or more organic solvents.
Beispiele für geeignete Lösemittel sind:
Kurzkettige, aliphatische Alkohole wie Methanol, Ethanol, Propanol oder Butanol, Diole, wie Ethylenglykol, Propandiol aber auch Polyethylenglykole und deren Ether, Ether wie Tetrahydrofuran, Dioxan, Amide wie N,N-Dimethylformamid, Hexamethylphosphorsäuretriamid, N-Methyl-2-pyrrolidon, Nitrile wie Acetonitril, Propionitril, Ketone wie Aceton, und andere Lösemittel wie beispielsweise Dimethylsulfoxid und Sulfolan. Auch die Verwendung organischer Säuren wie beispielsweise Essigsäure ist möglich.Examples of suitable solvents are:
Short-chain, aliphatic alcohols such as methanol, ethanol, propanol or butanol, diols such as ethylene glycol, propanediol but also polyethylene glycols and their ethers, ethers such as tetrahydrofuran, dioxane, amides such as N, N-dimethylformamide, hexamethylphosphoric triamide, N-methyl-2-pyrrolidone, Nitriles such as acetonitrile, propionitrile, ketones such as acetone, and other solvents such as dimethyl sulfoxide and sulfolane. The use of organic acids such as acetic acid is also possible.
Der Elektrolyt kann aber auch aus Wasser und einem nicht wasserlöslichen organischen Lösemittel wie t-Butylmethylether oder Methylenchlorid in Verbindung mit einem Phasentransferkatalysator bestehen.The electrolyte can also consist of water and a water-insoluble organic solvent such as t-butyl methyl ether or methylene chloride in conjunction with a phase transfer catalyst.
Zur Einstellung des für die Elektrolyse günstigsten pH-Wertes von 0 bis 12, vorzugsweise von 0,5 bis 11, und zur Erhöhung der Leitfähigkeit können dem Katholyten in der geteilten Zelle oder dem Elektrolyten in der ungeteilten Zelle anorganische oder organische Säuren zugesetzt werden, vorzugsweise Säuren wie Salz-, Bor-, Phosphor-, Schwefel-oder Tetrafluoroborsäure und/oder Ameisen-, Essig- oder Citronensäure und/oder deren Salze.In order to set the most favorable pH value for the electrolysis from 0 to 12, preferably from 0.5 to 11, and to increase the conductivity, inorganic or organic acids can be added to the catholyte in the divided cell or to the electrolyte in the undivided cell, preferably Acids such as hydrochloric, boric, phosphoric, sulfuric or tetrafluoroboric acid and / or formic, acetic or citric acid and / or their salts.
Auch die Zugabe organischer Basen kann zur Einstellung des für die Elektrolyse günstigen pH-Wertes nötig sein und/oder den Verlauf der Elektrolyse günstig beeinflussen. Geeignet sind primäre, sekundäre oder tertiäre C₂-C₁₂-Alkyl- oder Cycloalkylamine, aromatische oder aliphatisch-aromatische Amine oder deren Salze, anorganische Basen wie Alkali- oder Erdalkalihydroxyde wie beispielsweise Li-, Na-, K-, Cs-, Mg-, Ca-, Ba-hydroxyd, quartäre Ammoniumsalze, mit Anionen, wie beispielsweise die Fluoride, Chloride, Bromide, Jodide, Acetate, Sulfate, Hydrogensulfate, Tetrafluoroborate, Phosphate oder Hydroxyde, und mit Kationen wie beispielsweise C₁-C₁₂-Tetraalkylammonium, C₁-C₁₂-Trialkylarylammonium oder C₁-C₁₂-Trialkylalkylarylammonium, aber auch anionische oder kationische Emulgatoren, in Mengen von 0,01 bis 25 Gewichtsprozenten, vorzugsweise 0,03 bis 20 Gewichtsprozenten, bezogen auf die Gesamtmenge des Elektrolyten oder Katholyten.The addition of organic bases may also be necessary to set the pH value which is favorable for the electrolysis and / or have a favorable influence on the course of the electrolysis. Suitable are primary, secondary or tertiary C₂-C₁₂ alkyl or cycloalkylamines, aromatic or aliphatic-aromatic amines or their salts, inorganic bases such as alkali or alkaline earth metal hydroxides such as Li, Na, K, Cs, Mg, Ca, Ba hydroxide, quaternary ammonium salts, with anions such as fluorides, chlorides, bromides, iodides, acetates, sulfates, hydrogen sulfates, tetrafluoroborates, phosphates or hydroxides, and with cations such as C₁-C₁₂-tetraalkylammonium, C₁-C₁₂ -Trialkylarylammonium or C₁-C₁₂-trialkylalkylarylammonium, but also anionic or cationic emulsifiers, in amounts of 0.01 to 25 percent by weight, preferably 0.03 to 20 percent by weight, based on the total amount of the electrolyte or catholyte.
Bei der Elektrolyse in ungeteilter Zelle können dem Elektrolyten Verbindungen zugesetzt werden, die bei einem negativeren Potential oxidiert werden als die freigesetzten Halogenionen, um das Entstehen des freien Halogens zu vermeiden. Geeignet sind beispielsweise die Salze der Oxalsäure, der Methoxyessigsäure, der Glyoxylsäure, der Ameisensäure und/ober der Stickstoffwasserstoffsäure.During electrolysis in undivided cells, compounds can be added to the electrolyte which are oxidized at a more negative potential than the released halogen ions in order to avoid the formation of the free halogen. For example, the salts of oxalic acid, methoxyacetic acid, glyoxylic acid, formic acid and / or hydrochloric acid are suitable.
Weiterhin können dem Elektrolyten in der ungeteilten Zelle oder dem Katholyten in der geteilten Zelle Salze von Metallen mit einer Wasserstoffüberspannung von mindestens 0,25 V (bezogen auf eine Stromdichte von 300 mA/cm²) und/oder enthalogenierenden Eigenschaften zugesetzt werden. Als Salze kommen hauptsächlich infrage die löslichen Salze von Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Tl, Ti, Zr, Bi, V, Ta, Cr oder Ni, vorzugsweise die löslichen Pb-, Zn-, Cd-,Ag-und Cr-Salze. Die bevorzugten Anionen dieser Salze sind Cl⁻, SO₄⁻⁻, NO₃⁻, und CH₃COO⁻.Furthermore, the electrolyte in the undivided cell or the catholyte in the divided cell can be salts of Metals with a hydrogen overvoltage of at least 0.25 V (based on a current density of 300 mA / cm²) and / or dehalogenating properties can be added. The most suitable salts are the soluble salts of Cu, Ag, Au, Zn, Cd, Hg, Sn, Pb, Tl, Ti, Zr, Bi, V, Ta, Cr or Ni, preferably the soluble Pb, Zn, Cd, Ag and Cr salts. The preferred anions of these salts are Cl⁻, SO₄⁻⁻, NO₃⁻, and CH₃COO⁻.
Die Salze können der Elektrolyselösung direkt zugesetzt oder auch z.B. durch Zugabe von Oxiden, Carbonaten etc. - in einigen Fällen auch der Metalle selbst (sofern löslich) - in der Lösung erzeugt werden.The salts can be added directly to the electrolysis solution or, e.g. by adding oxides, carbonates etc. - in some cases also the metals themselves (if soluble) - in the solution.
Die Salzkonzentration im Elektrolyten der ungeteilten Zelle sowie im Katholyten der geteilten Zelle wird zweckmäßig auf etwa 10⁻⁵ bis 10 Gew.-%, vorzugsweise auf etwa 10⁻³ bis 5 Gew.-%, jeweils bezogen auf die Gesamtmenge des Elektrolyten oder Katholyten, eingestellt.The salt concentration in the electrolyte of the undivided cell and in the catholyte of the divided cell is expediently from about 10⁻⁵ to 10% by weight, preferably from about 10⁻³ to 5% by weight, in each case based on the total amount of the electrolyte or catholyte, set.
Man elektrolysiert bei einer Stromdichte von 1 bis 600 mA/cm², bevorzugt bei 10 bis 500 mA/cm², ohne Potentialkontrolle.Electrolysis is carried out at a current density of 1 to 600 mA / cm², preferably at 10 to 500 mA / cm², without potential control.
Die Elektrolysetemperatur liegt im Bereich von -10°C bis zur Siedetemperatur der Elektrolytflüssigkeit, vorzugsweise von 10° bis 90°C, insbesondere von 15° bis 80°C.The electrolysis temperature is in the range from -10 ° C to the boiling point of the electrolyte liquid, preferably from 10 ° to 90 ° C, in particular from 15 ° to 80 ° C.
Die Aufarbeitung des Elektrolyseproduktes erfolgt auf bekannte Weise, z.B. durch Extraktion oder Abdestillieren des Lösemittels. Die dem Katholyten zugesetzten Verbindungen können so dem Prozeß wieder zugeführt werden.The electrolysis product is worked up in a known manner, e.g. by extracting or distilling off the solvent. The compounds added to the catholyte can thus be returned to the process.
Das erfindungsgemäße Verfahren wird im folgenden durch Beispiele näher erläutert.The process according to the invention is explained in more detail below by examples.
Anhand eines Vergleichsbeispiels wird gezeigt, daß eine Quecksilberkathode, wie in J.Am.Chem.Soc. 80, 5402, 1959 und J.Chem.Research (M) 1983, 2401 beschrieben, zur selektiven Enthalogenierung ohne Bildung von Polymeren oder gesättigten Produkten nicht geeignet ist.Using a comparative example, it is shown that a mercury cathode as described in J.Am.Chem.Soc. 80 , 5402, 1959 and J.Chem.Research (M) 1983, 2401, is not suitable for selective dehalogenation without the formation of polymers or saturated products.
Ummantelte Glastopfzelle mit einem Volumen von 350 cm³
Anode: Platinnetz, Graphit- oder Bleiplatte (20 cm²)
Kathodenfläche: 12 cm²
Stromdichte: 83 mA/cm²
Elektrodenabstand: 1,5 cm
Klemmenspannung: 6-5V
Anolyt: verdünnte wäßrige Schwefelsäure oder methanolische Salzsäure
Kationenaustauschermembran: Einschichtenmembran aus einem Copolymerisat aus einem Perfluorsulfonylethoxyvinylether und Tetrafluorethylen
Stofftransport: durch Magnetrührer
Jacketed glass pot cell with a volume of 350 cm³
Anode: platinum mesh, graphite or lead plate (20 cm²)
Cathode area: 12 cm²
Current density: 83 mA / cm²
Electrode distance: 1.5 cm
Terminal voltage: 6-5V
Anolyte: dilute aqueous sulfuric acid or methanolic hydrochloric acid
Cation exchange membrane: single-layer membrane made from a copolymer of a perfluorosulfonylethoxy vinyl ether and tetrafluoroethylene
Mass transfer: by magnetic stirrer
Ummantelte Glastopfumlaufzelle mit einem Volumen von 450 cm³
Anode: Platinnetz, Graphit- oder Bleiplatte (20 cm²)
Kathodenfläche: 12 cm²
Elektrodenabstand: 1 cm
Anolyt: verdünnte wäßrige Schwefelsäure oder methanolische Salzsäure
Kationenaustauschermembran wie bei Elektrolysezelle 1
Stromdichte: 83 mA/cm²
Klemmenspannung: 5 V
Anode: platinum mesh, graphite or lead plate (20 cm²)
Cathode area: 12 cm²
Electrode distance: 1 cm
Anolyte: dilute aqueous sulfuric acid or methanolic hydrochloric acid
Cation exchange membrane as in electrolysis cell 1
Current density: 83 mA / cm²
Terminal voltage: 5 V
Kathode: imprägnierter Graphit
Ausgangselektrolyt:
250 g H₂O
5 g CCl₃-CClF-COOH
0,4 g Pb(OAc)₂ · 2H₂O
0,4 g NaOH
Temperatur: 32°C
Stromdichte: 249 mA/cm²
Klemmenspannung: 7 - 4,8 V
Stromverbrauch: 1,17 Ah
Cathode: impregnated graphite
Output electrolyte:
250 g H₂O
5 g CCl₃-CClF-COOH
0.4 g Pb (OAc) ₂ · 2H₂O
0.4 g NaOH
Temperature: 32 ° C
Current density: 249 mA / cm²
Terminal voltage: 7 - 4.8 V
Power consumption: 1.17 Ah
CCl₂=CF-COOH 3,4 g (97,2 %)
CHCl=CF-COOH 0,1 g (2,1 %)
pH-Wert: 0,85
CCl₂ = CF-COOH 3.4 g (97.2%)
CHCl = CF-COOH 0.1 g (2.1%)
pH: 0.85
Kathode: imprägnierter Graphit
Ausgangselektrolyt:
150 cm³ Aceton
10 g Tetrabutylammonium-Hydrogensulfat
20 g CF₂Br-CFBr-COOCH₃
Temperatur: 30-35°C
Stromdichte: 42 mA/cm²
Klemmenspannung: 40 - 32 V
Stromverbrauch: 3,57 Ah
Cathode: impregnated graphite
Output electrolyte:
150 cc acetone
10 g of tetrabutylammonium hydrogen sulfate
20 g CF₂Br-CFBr-COOCH₃
Temperature: 30-35 ° C
Current density: 42 mA / cm²
Terminal voltage: 40 - 32 V
Power consumption: 3.57 Ah
CF₂Br-CFBr-COOCH₃ 4,19 g
CF₂=CF-COOCH₃ 5,42 g (73,4 %)
CF₂Br-CFBr-COOCH₃ 4.19 g
CF₂ = CF-COOCH₃ 5.42 g (73.4%)
Kathode: Quecksilbersee
Ausgangselektrolyt:
200 cm³ Wasser
0,5 g NaOH
1,3 g CCl₃-CFCl-COOH
Temperatur: 32°C
Stromdichte: 28 mA/cm²
Klemmenspannung: 20 - 22 V
Stromverbrauch: 0,3 Ah
pH-Wert: 3,15 - 2,2
Cathode: Mercury Lake
Output electrolyte:
200 cm³ of water
0.5 g NaOH
1.3 g CCl₃-CFCl-COOH
Temperature: 32 ° C
Current density: 28 mA / cm²
Terminal voltage: 20 - 22 V
Power consumption: 0.3 Ah
pH: 3.15 - 2.2
CCl₃-CFCl-COOH 0,428 g
CCl₂=CF-COOH 0,206 g
CHCl=CF-COOH 0,204 g
CHCl₂-CFCl-COOH 0,131 g
unbekannte Produkte 0,022 gCCl₃-CFCl-COOH 0.428 g
CCl₂ = CF-COOH 0.206 g
CHCl = CF-COOH 0.204 g
CHCl₂-CFCl-COOH 0.131 g
unknown products 0.022 g
Claims (9)
- A process for the preparation of fluorine-containing compounds of the formula I
R¹ denotes a fluorine atom or a methyl or deuteromethyl group,R² and R³ are identical or different and denote a fluorine, chlorine, bromine, iodine, hydrogen or deuterium atom, andR⁴ is a cyano group or theby electrolytic reduction, which comprises subjecting fluorine-containing compounds of the formula II
R¹, R², R³ and R⁴ have the abovementioned meaning and R⁸ and R⁹ are identical or different and denote a chlorine, bromine or iodine atom, in an undivided cell or a divided cell in an electrolysis liquid comprising - in each case relative to the total amount of the electrolyte in an undivided cell or the catholyte in a divided cell -
0 to 100% by weight of water
100 to 0% by weight of one or more organic solvents, and
0 to 10% by weight of a salt of a metal having a hydrogen overvoltage of at least 0.25 V (based on a current density of 300 mA/cm²) and/or having dehalogenating properties,
to electrolysis at a temperature from -10°C to the boiling point of the electrolysis liquid and galvanostatically at a current density between 1 and 600 mA/cm², the cathode comprising lead, cadmium, zinc, copper, tin, zirconium or carbon. - The process as claimed in claim 1, wherein the electrolysis is carried out at a pH from 0 to 11 in the electrolyte in an undivided cell or in the catholyte in a divided cell.
- The process as claimed in claim 1, wherein
2,3-dibromo-2,3,3-trifluoropropionic acid,
2,3,3-trichloro-2,3-difluoropropionic acid,
2,3,3,3-tetrachloro-2-fluoropropionic acid,
2,3-dibromo-2,3-difluoropropionic acid or
2,3-dibromo-2-fluoropropionic acid
or the derivatives thereof,
is subjected to electrolysis. - The process as claimed in claim 1, wherein the electrolysis is carried out at a temperature from 10 to 90°C.
- The process as claimed in claim 1, wherein the electrolysis is carried out at a current density between 10 and 500 mA/cm².
- The process as claimed in claim 1, wherein the electrolysis is carried out in a divided cell with a batchwise cathode reaction and a continuous anode reaction.
- The process as claimed in claim 1, wherein the electrolysis is carried out in an undivided cell.
- The process as claimed in claim 1, wherein the electrolysis is carried out using a carbon cathode.
- The process as claimed in claim 1, wherein a soluble salt of copper, silver, gold, zinc, cadmium, mercury, tin, lead, thallium, titanium, zirconium, bismuth, vanadium, tantalum, chromium, cerium, cobalt or nickel is present in a concentration from about 10⁻⁵ to 10% by weight, relative to the total amount of the electrolyte or catholyte.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT88115288T ATE72269T1 (en) | 1987-09-23 | 1988-09-17 | PROCESS FOR THE PRODUCTION OF FLUORINATED ACRYLIC ACIDS AND THEIR DERIVATIVES. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19873731914 DE3731914A1 (en) | 1987-09-23 | 1987-09-23 | METHOD FOR THE PRODUCTION OF FLUORINATED ACRYLIC ACIDS AND THEIR DERIVATIVES |
| DE3731914 | 1987-09-23 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| EP0308838A1 EP0308838A1 (en) | 1989-03-29 |
| EP0308838B1 true EP0308838B1 (en) | 1992-01-29 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88115288A Expired - Lifetime EP0308838B1 (en) | 1987-09-23 | 1988-09-17 | Process for the production of fluorinated acrylic acids and their derivatives |
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| Country | Link |
|---|---|
| US (1) | US5114546A (en) |
| EP (1) | EP0308838B1 (en) |
| JP (1) | JPH01108389A (en) |
| KR (1) | KR890005302A (en) |
| CN (1) | CN1021977C (en) |
| AT (1) | ATE72269T1 (en) |
| AU (1) | AU623865B2 (en) |
| DE (2) | DE3731914A1 (en) |
| ES (1) | ES2030129T3 (en) |
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| DE4029068A1 (en) * | 1990-09-13 | 1992-03-19 | Hoechst Ag | METHOD FOR PRODUCING HALOGENATED ACRYLIC ACIDS |
| US5729645A (en) * | 1996-08-13 | 1998-03-17 | The Trustees Of The University Of Pennsylvania | Graded index optical fibers |
| DE102004023041B4 (en) | 2004-05-06 | 2012-02-16 | Eastman Kodak Co. | Method for aligning color separations of a printed image on a printing substrate |
| CN101717949B (en) * | 2009-11-17 | 2011-06-29 | 华东师范大学 | Method for preparing p-vinyl phenylacetic acid |
| CN103819332A (en) * | 2014-02-20 | 2014-05-28 | 常州市正锋光电新材料有限公司 | Preparation method for trichloroacrylic acid |
| CN104557512B (en) * | 2015-01-06 | 2016-05-11 | 山西大学 | A kind of 3-(bromo phenyl)-2, the preparation method of 2 '-difluoro propionic acid |
| RU2686408C1 (en) * | 2018-06-20 | 2019-04-25 | Федеральное государственное бюджетное учреждение науки Институт высокотемпературной электрохимии Уральского отделения Российской Академии наук | Electrolytic production method of aluminum |
| CN110438523B (en) * | 2019-09-05 | 2021-12-03 | 南京大学 | Catalyst-free electrochemical deuteration method taking heavy water as deuterium source |
| WO2024030044A1 (en) * | 2022-08-02 | 2024-02-08 | Владислав Владимирович ФУРСЕНКО | Method for producing aluminium by electrolysis of a solution of alumina in cryolite |
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| GB1498456A (en) * | 1975-12-17 | 1978-01-18 | Ici Ltd | Electrochemical process for the preparation of dihaloalkenes |
| JPS53132504A (en) * | 1977-04-26 | 1978-11-18 | Central Glass Co Ltd | Dehalogenation of halogenated hydrocarbons |
| DE3607446A1 (en) * | 1986-03-07 | 1987-09-10 | Hoechst Ag | METHOD FOR THE DEHALOGENATION OF CHLORINE AND BROMIC ACID ACIDS |
| DE3718726A1 (en) * | 1987-06-04 | 1988-12-22 | Hoechst Ag | METHOD FOR PRODUCING FLUORINATED VINYL ETHER |
-
1987
- 1987-09-23 DE DE19873731914 patent/DE3731914A1/en not_active Withdrawn
-
1988
- 1988-09-17 AT AT88115288T patent/ATE72269T1/en not_active IP Right Cessation
- 1988-09-17 ES ES198888115288T patent/ES2030129T3/en not_active Expired - Lifetime
- 1988-09-17 DE DE8888115288T patent/DE3868204D1/en not_active Expired - Fee Related
- 1988-09-17 EP EP88115288A patent/EP0308838B1/en not_active Expired - Lifetime
- 1988-09-21 CN CN88106784A patent/CN1021977C/en not_active Expired - Fee Related
- 1988-09-22 JP JP63236663A patent/JPH01108389A/en active Pending
- 1988-09-23 KR KR1019880012287A patent/KR890005302A/en not_active Application Discontinuation
- 1988-09-23 AU AU22726/88A patent/AU623865B2/en not_active Ceased
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1991
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Also Published As
| Publication number | Publication date |
|---|---|
| CN1032199A (en) | 1989-04-05 |
| JPH01108389A (en) | 1989-04-25 |
| ATE72269T1 (en) | 1992-02-15 |
| ES2030129T3 (en) | 1992-10-16 |
| DE3868204D1 (en) | 1992-03-12 |
| KR890005302A (en) | 1989-05-13 |
| EP0308838A1 (en) | 1989-03-29 |
| AU623865B2 (en) | 1992-05-28 |
| AU2272688A (en) | 1989-03-23 |
| CN1021977C (en) | 1993-09-01 |
| US5114546A (en) | 1992-05-19 |
| DE3731914A1 (en) | 1989-04-06 |
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