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
  • C25B3/00—Electrolytic production of organic compounds
  • C25B3/20—Processes
  • C25B3/27—Halogenation
  • C25B3/28—Fluorination
• • 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
• • 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
  • C25B15/023—Measuring, analysing or testing during electrolytic production
  • C25B15/025—Measuring, analysing or testing during electrolytic production of electrolyte parameters
  • C25B15/029—Concentration
  • C25B15/031—Concentration pH
• • 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
  • C25B15/08—Supplying or removing reactants or electrolytes; Regeneration of electrolytes
• • 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
  • C25B3/01—Products
  • C25B3/07—Oxygen containing compounds
• • 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

Definitions

• the invention relates to an electrochemical process for exchanging halogen atoms for hydrogen or deuterium atoms in halogen (meth) acrylic 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 variety of products. Above all, however, they are 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 can be used to produce 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 aeronautical engineering and are suitable starting materials for polymer optical fibers, with deuterated derivatives being of particular interest because of their better optical properties.
• deuterated and halogenated acrylic acid derivatives There are hardly any known syntheses for such deuterated and halogenated acrylic acid derivatives.
• the deuterated derivatives of ⁇ -fluoroacrylic acid for example, can be prepared via the corresponding deutero- or dideuterotetrafluorooxetane, however, very expensive deuterated reagents such as mono- or dideuteroformaldehyde have to be used in the synthesis of such tetrafluorooxetanes and high yield losses have to be accepted.
• tetrafluorooxetanes are very toxic chemicals.
• halogen atoms can be partially or completely replaced by hydrogen and in some cases also by deuterium atoms by electrochemical reduction (cf. The Chemistry of the Carbon-Halogen Bond, S. Patai (ed.), Wiley, New York (1973), p. 979).
• the hydrogen or deuterium atoms are generally removed from the solvent.
• the halogen atoms can be split off particularly easily if they are in the vicinity of an electron-withdrawing functional group, for example a carbonyl function.
• an electron-withdrawing functional group for example a carbonyl function.
• electrochemical halogen elimination in ⁇ , ⁇ -unsaturated carboxylic acids for example the de-bromination of 2-bromofumaric acid to fumaric acid, in aqueous solutions (J. Org. Chem. 34 (1969) 3359).
• Another disadvantage of this method is that polymerization sensitive products such as e.g. 2-chloroacrylic acid are obviously not stable under the conditions described, but polymerize. After electrochemical dehalogenation of 2,3,3-trichloropropionic acid to 2-chloroacrylic acid, only a low molecular weight polymeric product can be isolated. This process is therefore unsuitable for the preparation of 2-haloacrylic acids, and acrylic acid cannot be produced under these conditions either.
• the object can be achieved if the electrolysis is carried out in water or deuterium oxide, optionally in the presence of an auxiliary solvent and / or a salt of a metal with a hydrogen overvoltage of more than 0.25 V.
• R1 is a hydrogen, deuterium or halogen atom or a methyl, deuteromethyl, nitrile, halomethyl or deuterohalomethyl group, preferably a halogen atom, in particular a fluorine atom.
• At least one of R1, R2 or R3 is a halogen atom.
• Perhalogenated acrylic acids such as trichloro, tribromo and triiodacrylic acid or 2-chloro-3,3-difluoro, 3,3-dichloro-2-fluoro, 3,3, -dibromo-2-fluoro, 3,3, - Diiodo-2-fluoro, 2-bromo-3,3-dichloro, 3,3-dibromo-2-chloro, 3,3-dibromo-2-iodo, 3-chloro-2,3-difluoro- , 2-chloro-3,3-diiodo and 2-bromo-3,3-diiodoacrylic acid or 3-bromo-2,3-dichloro, 2,3-dibromo-3-chloro, 2,3-dibromo- 3-iodo, 3-bromo-2,3-dichloro, 2,3-dibromo-3-chloro, 2,3-dibromo- 3-
• Dihalogenated acrylic acids such as 3,3-dichloro, 3,3-dibromo and 3,3-diiodacrylic acid or 3-bromo-3-chloro, 3-chloro-3-fluoro, 3-bromo-3-fluoro and 3-bromo-3-iodacrylic acid or 2,3-dichloro, 2,3-dibromo and 2,3-diiodacrylic acid or 3-chloro-2-fluoro, 3-chloro-2-iodo, 2-chloro 3-fluoro, 2-chloro-3-iodo, 3-bromo-2-fluoro, 3-bromo-2-iodo, 2-bromo-3-fluoro and 2-bromo-3-iodacrylic acid, preferably 3-chloro-2-fluoro, 3-bromo-2-fluoro and 2-chloro-3-fluoro or 2-bromo-3-fluoroacrylic acid, especially 3-chloro-2-fluoroacrylic acid.
• Monohalogenated acrylic acids such as 2-chloro, 2-bromo and 2-iodacrylic acid or 3-chloro, 3-bromo and 3-iodo-acrylic acid.
• Halogenated methacrylic acids such as 2-chloromethyl, 2-bromomethyl and 2-iodomethyl acrylic acid or 2-dichloromethyl, 2-dibromomethyl and 2-chlorodifluoromethyl acrylic acid or 3,3-dibromo-2-methyl and 3,3-dichloro-2-methylacrylic acid or 3-chloro-2-methyl- and 3-bromo-2-methyl-acrylic acid, preferably 3-bromo-2-methyl-, 3,3-dibromo-2-methyl-, 3,3-dichloro-2-methyl- or 2-chloromethylacrylic acid, especially 3,3-dibromo-2-methyl- and 3,3-dichloro-2-methylacrylic acid.
• Halogenated cyanoacrylic acids such as 3-chloro-2-cyano-, 2-chloro-3-cyano- and 3-chloro-3-cyanoacrylic acid, preferably 3-chloro-2-cyanoacrylic acid.
• 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 the anode and cathode compartments.
• Preferred Ion exchange membranes are cation exchange membranes made of 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, such as, for example, in beaker or plate and frame cells or cells with fixed bed or fluidized bed electrodes. Both the monopolar and the bipolar circuit 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., but also alloys such as lead-tin or zinc-cadmium are suitable.
• the use of carbon cathodes is preferred, particularly in the case of electrolysis in acidic electrolytes, since some of the electrode materials listed above, for example Zn, Sn, Cd and Pb, can suffer corrosion.
• all possible carbon electrode materials come into question as carbon cathodes, such as electrode graphites, impregnated graphite materials, carbon felts and also glassy carbon.
• electrodes made of materials which are conducive to catalytic hydrogenation such as platinum or platinum / rhodium alloys, is also conceivable.
• All materials on which the known anode reactions take place can be used as anode material.
• Examples are lead, lead dioxide on lead or other carriers, platinum or with noble metal oxides e.g. 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 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.
• the catholyte fluids contain water or deuterium oxide.
• auxiliary solvents can be added to the electrolyte in the undivided cell or the catholyte in the divided cell.
• auxiliary solvents can be added to the electrolyte in the undivided cell or the catholyte in the divided cell.
• Examples 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.
• two-phase electrolysis with the addition of one is not water-soluble organic solvent such as t-butyl methyl ether or methylene chloride in combination with
• the proportion of auxiliary solvents in the electrolyte or the catholyte can be 0 to 100% by weight, preferably 10 to 80% by weight, based on the total amount of the electrolyte or catholyte.
• 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 to the electrolyte in the undivided cell or the catholyte in the divided cell.
• Possible salts are mainly 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 and Cr salts.
• the preferred anions of these salts are Cl ⁇ , SO , NO , 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.
• 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.
• inorganic or organic acids can be added to the catholyte in the divided cell or 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.
• Electrolysis is carried out at a current density of 1 to 500 mA / cm2, preferably at 10 to 300 mA / cm2.
• the electrolysis temperature is in the range from -10 ° C to the boiling point of the electrolysis liquid, preferably from 10 ° to 90 ° C, in particular from 15 ° to 80 ° C.
• the electrolysis product is worked up in a known manner, for example by extraction or distillation of the solvent.
• the compounds added to the catholyte can thus be returned to the process.
• one or more halogen atoms can be selectively split off from ⁇ , ⁇ -unsaturated carboxylic acids of the formula I or their derivatives and replaced by hydrogen or deuterium atoms without significant losses due to the above-mentioned competitive reactions.
• Comparative Example B almost exclusively polymer and a mixture of a large number of unknown products are formed on mercury in undivided cells.
• the yield information relates to the turnover of the starting product.
• Electrolytic cell Coated glass pot cell with a volume of 350 ml
• Anode Platinum mesh or lead plate (20 cm2)
• Cathode area 38 cm2
• Electrode gap 1.5 cm
• Anolyte dilute aqueous sulfuric acid
• Cation exchange membrane Two-layer membrane made from a copolymer of a perfluorosulfonylethoxy vinyl ether and tetrafluoroethylene Mass transfer: by magnetic stirrer Temperature: 30 ° C
• Terminal voltage 20 V at the beginning of the electrolysis, then decreasing to 5-7 V
• the catholyte was exhaustively extracted with diethyl ether and the product mixture was precipitated as ammonium salt by introducing ammonia or the solvent was removed by distillation.
• Electrolytic cell divided plate and frame circulation cell
• Electrodes Electrode graphite EH (Sigri, Meitingen) Area: 200 cm2
• Electrode gap 4 mm
• Turbulence booster Polyethylene nets
• Catholyte 2.5 l of water
• 11 g NaOH 1 g Pb (OAc) 2 ⁇ 3 H2O 114 g of 3-bromomethacrylic acid
• Anolyte conc.
• Terminal voltage 8 V at the beginning, decreasing to 5.6 V
• Current density 120 mA / cm2
• Flow 800 l / h
• Temperature 30 - 36 ° C
• the current yield for the methacrylic acid was 60%.
• Electrolytic cell coated glass pot cell with a volume of 350 ml, divided Anode: Pt network (20 cm2) Cathode: Mercury Lake (approx. 60 cm2 surface) Cation exchange membrane: as in example 1 Electrode gap: 1.5 cm Temperature: 30 ° C cathod. Current density: 33 mA / cm2 Terminal voltage: 50-9 V Anolyte: Verd. H2SO4 Catholyte: 30 ml of ethanol 70 ml water 1 g tetramethylammonium iodide 2 g 3,3-dichloro-2-fluoroacrylic acid Power consumption: 4.05 Ah
• Electrolytic cell coated glass pot cell with a volume of 350 ml, undivided Anode: Platinum net (20 cm2) Cathode: Mercury Lake (approx. 60 cm2 surface) Electrode gap: 1.5 cm Mass transfer: by magnetic stirrer Temperature: 30 ° C cathod. Current density: 33 mA / cm2 Terminal voltage: 10-9 V Electrolyte: 30 g ethanol 70 g water 1 g tetramethylammonium iodide 2 g 3,3-dichloro-2-fluoroacrylic acid Power consumption: 4.05 Ah
• Catholyte 70 ml H2O 30 g ethanol 1 g tetramethylammonium iodide 3 g 2,3,3-trichloracrylic acid Power consumption: 2.75 Ah

Landscapes

• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Metallurgy (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Automation & Control Theory (AREA)
• Analytical Chemistry (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Primary Cells (AREA)
• Secondary Cells (AREA)
• Manufacture Of Macromolecular Shaped Articles (AREA)
• Conductive Materials (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (2)

Family

ID=6321120

Family Applications (1)

Country Status (9)

Cited By (2)

Families Citing this family (21)

Citations (1)

Family Cites Families (2)

• 1987
  • 1987-02-17 DE DE19873704915 patent/DE3704915A1/de not_active Withdrawn
• 1988
  • 1988-02-11 AT AT88102011T patent/ATE65555T1/de not_active IP Right Cessation
  • 1988-02-11 ES ES88102011T patent/ES2025223B3/es not_active Expired - Lifetime
  • 1988-02-11 EP EP88102011A patent/EP0280120B1/fr not_active Expired - Lifetime
  • 1988-02-11 DE DE8888102011T patent/DE3863794D1/de not_active Expired - Fee Related
  • 1988-02-15 CN CN88100844A patent/CN1019208B/zh not_active Expired
  • 1988-02-16 JP JP63031993A patent/JPS63203782A/ja active Pending
  • 1988-02-16 KR KR1019880001630A patent/KR880010157A/ko not_active Ceased
  • 1988-02-16 US US07/155,767 patent/US4800012A/en not_active Expired - Fee Related
  • 1988-02-17 AU AU11907/88A patent/AU595683B2/en not_active Ceased

Patent Citations (1)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events