EP0965658A1 - Verfahren zur elektrochemischen Umsetzung organischer Verbindungen unter Anwendung der Solid-Polymer-Elektrolyte-Technologie in einer Elektrolyseflüssigkeit in der Nähe des Siedepunktes - Google Patents
Verfahren zur elektrochemischen Umsetzung organischer Verbindungen unter Anwendung der Solid-Polymer-Elektrolyte-Technologie in einer Elektrolyseflüssigkeit in der Nähe des Siedepunktes Download PDFInfo
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- EP0965658A1 EP0965658A1 EP99111276A EP99111276A EP0965658A1 EP 0965658 A1 EP0965658 A1 EP 0965658A1 EP 99111276 A EP99111276 A EP 99111276A EP 99111276 A EP99111276 A EP 99111276A EP 0965658 A1 EP0965658 A1 EP 0965658A1
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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
- C25B3/23—Oxidation
Definitions
- This procedure is compared to conventional electrolysis techniques advantageous because it produces particularly high yields can be achieved and a time-consuming work-up is unnecessary, since the use of conductive electrolytes is avoided can.
- the method according to the invention is basically suitable for electrochemical oxidation or reduction of all compounds, for which the SPE technology comes into consideration, the anodic Oxidations are preferred.
- benzaldehyde dimethyl acetal would have the oxidation number 2, since there is a group A, which is assigned the oxidation number 1 (-CH (OCH 3 ) -) and a group B, which is also assigned the oxidation number 1 (-OCH 3 ), contains.
- mixtures of substances are used in the process according to the invention formed with different oxidation numbers. If in such cases, products of formula (I) with a real low oxidation number are not desired, it is possible this of those with the higher oxidation number by conventional Methods to separate, and the former again after the inventive method for producing the desired Use products.
- p-methoxytoluene oxidation number 0
- p-methoxybenzyl methyl ether oxidation number 1
- the method is particularly suitable for electrochemical Methoxylation of methine, methylene or methyl groups aliphatic or alicyclic mono- or diether preferably with 3 to 6 carbon atoms in the ⁇ -position an ether oxygen atom (starting ether) with formation of compounds in which at least one H atom of methine, Methylene or methyl groups of the starting ether through a Methoxy group is substituted.
- start ether an ether oxygen atom
- Particularly suitable starting ethers are 1,2-dimethoxyethane, Tetrahydrofuran (THF), tetrahydropyran or 1,4-dioxane.
- Electrolytic cells using a solid polymer electrolyte (SPE) work are generally known (see. “Ion exchange membranes in electrolysis and electroorganic synthesis ", Dr.-Ing. Jakob Jörissen, Progress Reports VDI Series 3 No. 442; Düsseldorf: VDI Verlag 1996, Chapter 4).
- Ion exchange membranes are particularly suitable for films processed polymers such as polyethylene, polyacrylates, polysulfone and perfluorinated polymers with negatively charged groups such as Carboxylate and sulfonate groups (cation exchange membranes) or positively charged groups like protonated or quaternized amino groups (anion exchange membranes).
- polymers such as polyethylene, polyacrylates, polysulfone and perfluorinated polymers with negatively charged groups such as Carboxylate and sulfonate groups (cation exchange membranes) or positively charged groups like protonated or quaternized amino groups (anion exchange membranes).
- Such films are commercially available and, for example, among the Trade names Nafion®, (E.I. Du Pont de Nemours and Company) and Gore Select® (W.L. Gore & Associates, Inc.).
- the solid electrolyte in the form of a gel swollen with an optionally N-alkylated C 1 -C 15 -carboxylic acid amide, which can be obtained by allowing the cation exchange membrane to swell in the carboxylic acid amide until the gel formed 1.2 to 10 times the weight of the cation exchange membrane used.
- the increase in weight can be determined by weighing the membrane before swelling, immediately after removal from the swelling medium by dabbing it with an absorbent fleece to remove the liquid wetting it and then immediately carrying out a differential weighing.
- the swelling with N, N-dimethylformamide is particularly advantageously carried out by.
- the swelling is expediently at a Temperature from 50 to 120 ° C carried out.
- the solid electrolyte can be a single one Cation exchange membrane or around a layer of several, preferably act 2 to 10 membranes one above the other.
- the solid electrolyte conveniently has a thickness of 0.025 to 0.2 mm.
- anode or cathode materials with which the preferred entire surface of the solid electrolyte is in contact come porous, electrically conductive materials, in particular Graphite felt sheets, carbon felt sheets, or textile materials, that at the contact surface with the solid electrolyte with carbon are covered.
- the electrolysis liquid that is in contact with the electrode is generally a solution from the substrates, possibly the reaction products of the substrates and a solvent If the substrates at the defined operating temperatures of the electrolytic cells that are liquid can on the The use of solvents can be dispensed with.
- organic solvents which under practically no reaction to the process conditions for example, optionally N-alkylated carboxamides having 1 to 15 carbon atoms such as formamide, N-methylformamide, N, N, -dimethylformamide, Acetamides, N-methylpyrrolidone, pyrrolidone and benzamide, N-alkylated ureas with 3 to 15 carbon atoms such as N, N, N ', N'-tetramethyurea, Ether, acetonitrile, benzonitrile, sulfolane, and esters such as methyl acetate.
- the Proportion of water in the electrolysis liquid no more than 10, preferably 2 and very particularly preferably not more than 0.5 % By weight.
- the electrolysis liquid contains essentially none of the lead electrolytes otherwise used in conventional cells such as acids, bases or electrolytes, i.e. that they are in the generally less than 10, particularly preferably less than 1, very particularly preferably less than 0.1% by weight of these lead electrolytes contains.
- the methoxylation of THF is advantageously carried out in bulk carried out, i.e. the electrolysis solution essentially contains only THF and methanol.
- the temperature of the electrolysis liquid is at the boiling point or up to 5, preferably up to 2 ° C below the boiling point.
- a particularly favorable effect can be achieved if the Electrolysis liquid boils evenly in the cell. This will the temperature in the cell prefers as close to the Boiling point raised that the reaction mixture through the Heat development during the reaction only on the membrane surface comes to a boil. There is a certain gas bubble development quite desirable, but a violent boiling must strong gas bubble development can be avoided.
- the liquid in particular should not boil so much that more than 5% of the Electrolysis cell are displaced by gas bubbles, otherwise the Mass transport to the membrane is no longer guaranteed and the Membrane is destroyed. This effect is sudden Voltage rise connected. Destruction caused by this the membrane can be reliably prevented by automatic voltage monitoring in the event of too high a voltage Voltage of electrical current through the cell is turned off.
- the method according to the invention is expediently carried out in this way by making the electrolysis liquid parallel to the anode Solid electrolyte / anode interface preferably continuous flows through.
- Flow velocities are suitable Electrolysis liquid relative to the anode from 1 to 10 cm / s.
- the current density is generally 0.1 to 40, preferably 1 to 10 A / dm 2 .
- the voltages required to achieve these current densities are generally 2 to 20, preferably 3 to 10 volts. At higher voltages there is a risk of irreversible damage to the solid electrolyte.
- Oxidation of organic substrates on the counter electrode (cathode) usually protons reduced to hydrogen.
- the cells in which the procedure can be carried out are known and for example in loc. cit, chapter 4.2 and in the DE-A-19533773.
- Suitable for practicing the process on an industrial scale especially those described in DE-A-19533773 serially switched plate stack cells.
- plate stack cells are in contact with each other standing layers aligned parallel to each other, where the layers are made of porous, electrical conductive material and that from the solid electrolyte alternate.
- the basic structure of plate stack cells is for example from "Experiences with an Undivided Cell", Franz Wenisch et al., AIChE Symposium Series No 185, Vol. 75, pages 14 to 18 known.
- Table 1 shows the conditions under which examples and Comparative examples were carried out.
- part 1 which reflects the state of the Technology represents (runtime up to 650h) and one subsequent part 2, which was carried out according to the invention (Runtime up to 650h).
- part 1 when operating the electrochemical Cell at 50 ° C is a slow but steady one Rise in cell voltage is recognizable after 650 hours of operation (27 days) led to a cell voltage of over 16 volts. In comparable previous attempts, such occurred Conditions some time after the specified operating time Destruction of the membrane.
- the present invention was at 650 hours Operating time the temperature up to the boiling point of the liquid increased in the cell (in this example 68 ° C, see Fig.1). The cell voltage immediately dropped by about 5 volts. Of the main advantage for the technical application is that the cell voltage no longer showed a rising trend.
- Fig. 2 shows the application of the present invention, ie the operation of the SPE cells with boiling cell content, using eight examples (test parts B1 to B8) with changing operating conditions with regard to the concentrations and the current density (see Table 1).
- Test parts B1 to B8 With the moderate conditions at the beginning of the term (1 and 2), an increase in voltage could be completely avoided.
- a current density of 500 A / m 2 (3 and 6) which is a relatively high value for electro-organic syntheses, there were initially significantly higher values of the cell voltage, but with a clearly decreasing tendency.
- stable operation could be achieved at an increased level of the cell voltage, although damage to the cell components cannot be ruled out due to the current high current density (3 and 6).
- Example 8 provided a particularly advantageous result with an acceptably high and, above all, stable cell voltage and a favorable current yield of the products: the current yield of the mainly desired double methoxylated product was high, and the moderate single-methoxylated product formed can , if it is not desired, can be returned after separation from the main product and further implemented.
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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)
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE19827325 | 1998-06-19 | ||
DE19827325A DE19827325A1 (de) | 1998-06-19 | 1998-06-19 | Verfahren zur elektrochemischen Umsetzung organischer Verbindungen unter Anwendung der Solid-Polymer-Elektrolyte-Technologie in einer Elektrolyseflüssigkeit in der Nähe des Siedepunktes |
Publications (1)
Publication Number | Publication Date |
---|---|
EP0965658A1 true EP0965658A1 (de) | 1999-12-22 |
Family
ID=7871380
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP99111276A Withdrawn EP0965658A1 (de) | 1998-06-19 | 1999-06-10 | Verfahren zur elektrochemischen Umsetzung organischer Verbindungen unter Anwendung der Solid-Polymer-Elektrolyte-Technologie in einer Elektrolyseflüssigkeit in der Nähe des Siedepunktes |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0965658A1 (ja) |
JP (1) | JP2000034589A (ja) |
DE (1) | DE19827325A1 (ja) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE10025937A1 (de) * | 2000-05-26 | 2001-11-29 | Fuma Tech Gmbh | Perfluorsulfonsäure-Membranen, Verfahren zu ihrer Herstellung und Verwendung für Brennstoffzellen |
WO2004046408A2 (en) | 2002-11-20 | 2004-06-03 | Intelligent Energy, Inc. | Electrochemical reformer and fuel cell system |
JP5997222B2 (ja) | 2014-09-05 | 2016-09-28 | 富士重工業株式会社 | インジェクタ駆動装置 |
CN106544692B (zh) * | 2016-10-28 | 2018-09-14 | 华南理工大学 | 一种3-硒芳基吲哚类化合物的电化学制备方法 |
CN106567104B (zh) * | 2016-10-31 | 2018-12-11 | 华南理工大学 | 1,1’-二吲哚甲烷类衍生物的电化学合成方法 |
Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4462876A (en) * | 1983-03-25 | 1984-07-31 | Ppg Industries, Inc. | Electro organic method and apparatus for carrying out same |
EP0436055A1 (en) * | 1990-01-04 | 1991-07-10 | The Electrosynthesis Company, Inc. | High yield methods for electrochemical preparation of cysteine and analogues |
-
1998
- 1998-06-19 DE DE19827325A patent/DE19827325A1/de not_active Withdrawn
-
1999
- 1999-06-10 EP EP99111276A patent/EP0965658A1/de not_active Withdrawn
- 1999-06-21 JP JP11174637A patent/JP2000034589A/ja not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4462876A (en) * | 1983-03-25 | 1984-07-31 | Ppg Industries, Inc. | Electro organic method and apparatus for carrying out same |
EP0436055A1 (en) * | 1990-01-04 | 1991-07-10 | The Electrosynthesis Company, Inc. | High yield methods for electrochemical preparation of cysteine and analogues |
Non-Patent Citations (2)
Title |
---|
JÖRISSEN J.: "Ion exchange membranes as solid polymer electrolytes (spe) in electro-organic syntheses without supporting electrolytes", ELECTROCHEMICA ACTA, vol. 41, no. 4, 1996, pages 553 - 562, XP002115510 * |
R.S. GIRT K. SCOT: "Pretreatment of ion-exchange membranes for use in the solid polymer electrolyte reactor", 8 April 1998, INSTITUTION OF CHEMICAL ENGINEERS, RUGBY UK, XP002115511 * |
Also Published As
Publication number | Publication date |
---|---|
DE19827325A1 (de) | 1999-12-23 |
JP2000034589A (ja) | 2000-02-02 |
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