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
  • C25B3/01—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
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/02—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form
  • C25B11/03—Electrodes; Manufacture thereof not otherwise provided for characterised by shape or form perforated or foraminous
  • C25B11/031—Porous electrodes
• • 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
  • C25B11/042—Electrodes formed of a single 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
  • 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
  • C25B11/052—Electrodes comprising one or more electrocatalytic coatings on a substrate
• • 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
  • C25B11/055—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material
  • C25B11/057—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the substrate or carrier material consisting of a single element or compound
  • C25B11/061—Metal or alloy
  • C25B11/063—Valve metal, e.g. titanium
• • 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
  • C25B11/075—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound
  • C25B11/081—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of a single catalytic element or catalytic compound the element being a noble metal
• • 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
  • C25B3/09—Nitrogen 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
  • C25B3/23—Oxidation
• • 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
  • C25B9/00—Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features
  • C25B9/17—Cells comprising dimensionally-stable non-movable electrodes; Assemblies of constructional parts thereof

Definitions

• the object of the present invention is to provide a process for the electrochemical hydrogenation of organic compounds that does not have the disadvantages of the prior art.
• the object of the present invention is to provide a process for the electrochemical hydrogenation of organic compounds that can be carried out in an undivided cell, that is highly selective and produces few undesired oxidative by-products or impurities (e.g., metal impurities), and that uses electrolytes and electrodes that can be manufactured, operated, and purified or reused with little effort.
• the hydrogenation should be carried out without the use of electrocatalysts in order to keep the effort required for process control and reprocessing as low as possible.
• the electrodes it is furthermore desirable that they do not function as sacrificial electrodes and do not require (re)activation or (re)plating.
• the electrolytes it is furthermore desirable that they be as harmless to health as possible, in particular, that they are not carcinogenic.
• the present process is a process for the electrochemical hydrogenation of an organic compound selected from the group consisting of ketones, enones, aromatics, and nitriles. If a ketone is used as the reactant, the corresponding hydroxyl-containing compound is formed by hydrogenation. If an enone is used as the reactant, the corresponding unsaturated hydroxyl-containing compound, the corresponding saturated carbonyl-containing compound (i.e., ketone or aldehyde), or the corresponding saturated hydroxyl-containing compound can be produced by hydrogenation.
• the process according to the invention is particularly suitable for the hydrogenation of enones to the corresponding saturated hydroxyl-containing compounds.
• the corresponding, optionally partially unsaturated, cyclic hydrocarbon compound is formed by hydrogenation.
• the process according to the invention is particularly suitable for the hydrogenation of aromatics to the corresponding saturated cyclic hydrocarbon compounds.
• the organic compounds used selected from the group consisting of ketones, enones, aromatics, and nitriles, cannot exclusively be organic compounds containing the aforementioned functionalities.
• the term "organic compound selected from the group consisting of ketones, enones, aromatics, and nitriles” therefore includes, here and below, organic compounds that, in addition to the aforementioned functionalities, also contain other, non-electrochemically hydrogenatable functionalities or substituents.
• the aforementioned organic compounds can also be organic compounds that, in addition to the oxygen and nitrogen atoms present in any ketone, enone, and nitrile functionalities, contain additional oxygen and/or nitrogen and/or other heteroatoms.
• the process according to the invention is particularly suitable for the electrochemical hydrogenation of organic compounds which contain exclusively carbon and hydrogen and optionally also nitrogen and/or oxygen.
• the process according to the invention is particularly suitable for the hydrogenation of isophorone, isophoronenitrile, a mixture of 2,2,4- and 2,4,4-trimethylhexanedinitrile, 4,4'-methylenedianiline and naphthalene.
• the process according to the invention is also particularly suitable for the electrochemical hydrogenation of ketones. Even more preferably, the process according to the invention is a process for the electrochemical hydrogenation of ketones containing exclusively carbon, hydrogen, and oxygen.
• the process according to the invention is particularly suitable for the hydrogenation of isophorone to 3,3,5-trimethylcyclohexanol.
• the concentration of the organic compound is preferably 0.01 - 1 mol/l, preferably 0.048 - 0.1 mol/l, since the organic compound can then be dissolved particularly well.
• the process is carried out in an undivided cell.
• the electrodes used are aligned parallel.
• water i.e., H 2 O
• water is used as the hydrogen source.
• water is therefore present as the hydrogen source and solvent.
• one or more further solvents may preferably be present.
• a solvent selected from the group consisting of methanol, isopropanol, tetrahydrofuran, acetone, and acetonitrile can be used as the further solvent.
• a further solvent is present, it is preferably present in mass fractions of 0.01:1 to 10:1 and particularly preferably in mass fractions of 0.5:1 to 2:1, based on the mass of the water present.
• a mixture of water and a solvent selected from methanol and isopropanol since this allows acetone or formic acid to be generated as anodic by-products, which can advantageously be used as starting materials for preparing the compounds to be hydrogenated.
• Very particular preference is given to using a mixture of isopropanol and water in which the mass fraction of isopropanol used is 0.8:1 to 1.2:1, even more preferably 1:1, based on the mass of the water present.
• Equally preferred is using a mixture of methanol and water in which the mass fraction of methanol used is 0.8:1 to 1.2:1, even more preferably 1:1, based on the mass of the water present.
• the electrochemical hydrogenation process is carried out in the presence of sulfuric acid (H 2 SO 4 ) in the electrolyte.
• Sulfuric acid is preferably the only electrolyte present.
• one or more additional electrolytes can also be used. If additional electrolytes are added, they can preferably be selected from the group consisting of boric acid, sodium sulfate, and alkylammonium salts. preferably in proportions of 0.01 - 30 mol-%, more preferably 0.01 - 10 mol-%, most preferably 0.01 - 5 mol-% based on the amount of all electrolytes.
• the sulfuric acid (H 2 SO 4 ) is preferably used in proportions of 0.01 - 10 wt.%, more preferably 0.1 - 5 wt.%, even more preferably 0.5 - 2.5 wt.%, based on the mass of the water present.
• the pH of the electrolyte solution used in the process according to the invention i.e., the aqueous electrolyte solution containing the organic compound present during the reaction, is preferably between 0.01 and 5, more preferably between 0.1 and 2, and even more preferably between 0.8 and 1.5.
• the pH is determined at room temperature (20°C) using pH paper or pH probes, preferably pH paper.
• the cathode used in the process according to the invention is a pure-material electrode made of a material selected from graphite, nickel, and steel. Pure-material electrodes are unsupported and untreated solid-body electrodes made of a defined alloy or a defined material composition.
• a solid body has a uniform structure on both the front and back sides (no carrier material).
• a solid body is homogeneous (a defined structure both within the body and on the surface).
• a solid body can be divided as desired, resulting in another solid body. This is due to the same composition in the body and on the surface.
• the cathode is particularly preferably a nickel foam electrode, as this leads to particularly high yields.
• the anode used in the process according to the invention is an electrode selected from solid and supported electrodes with an active material selected from platinum, graphite, boron-doped diamond, ruthenium oxide, platinum oxide and/or iridium oxide.
• the corresponding anodes are solid-body electrodes or supported electrodes, in which the respective active material is the aforementioned electrode material.
• the aforementioned anodes are solid-body or supported electrodes with an active material selected from platinum, graphite, boron-doped diamond, ruthenium oxide, platinum oxide, and/or iridium oxide. If a support is used, this is preferably a material selected from graphite, tantalum, titanium, iron, and silicon. Electrodes with a support selected from titanium, iron, and silicon with a coating selected from ruthenium oxide, platinum oxide, and/or iridium oxide are also commercially available as DSA electrodes (dimensionally stable anodes).
• the anode used is particularly preferably a platinum electrode.
• the platinum is preferably pressed, welded, or coated onto a carrier material.
• carrier materials that are stable to the electrolyte are used, preferably tantalum.
• the process according to the invention enables hydrogenation in batch and continuous processes.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

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• 2024
  • 2024-03-20 EP EP24164800.5A patent/EP4621104A1/fr active Pending
• 2025
  • 2025-03-18 WO PCT/EP2025/057365 patent/WO2025196048A1/fr active Pending

Patent Citations (9)

Non-Patent Citations (6)

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