Elektrodenvorrichtung

The available invention concerns a Etektrodenvorrichtung, those for use during electro-chemical processes suitably ist.

Electro-chemical processes cover electro-chemical reactions, which run off in an electro-chemical line as redox reactions. For electro-chemical reactions electrodes, i.e. at least a cathode and at least an anode, are notwendig.

By use a reaction knows of different electrode materials and conditions more or less efficiently accomplished werden.

Electro-chemical processes kSnnen for example for the synthesis of a multiplicity of chemical compounds, e.g. by reduction or oxidation of suitable raw materials, and to Wasserund sewage conditioning uses werden.

Different electro-chemical processes for the synthesis of inorganic and organic compounds are for example in C.A.C. Sequeira et al., J. Braz. Chern. Soc., VOL. 00, No.

00, p. 1-20 (2009) indicated. Special applications cover the reduction from oxygen to hydrogen peroxide in the Wasseroder waste water treatment and in another aspect the reduction of the amino acid L-Cystein from the dimeren LCystin.

in an aspect Cathode materials with a high surface time achievement (kg/m2/h) it has frequently the disadvantage that by the use of mercury and lead as electrode materials the product with heavy metals is polluted. Other materials are not steady partly opposite from Elektroytlösungen, like HC1-Lösungen. Admitted electrodes, which are ausgerohrt as plates, it has, in particular with requirements of high product quality (conversion more largely than 99%) often the disadvantage that long response times (20 to 30 hours) are taken in purchase müssen.

It already three-dimensional, porous electrodes begun, which exhibit high values during the surface time achievement and which not for the contamination of a product with mercury or lead leading, if they are out-arranged as porous carbon electrodes or as porous Metallelektroden, which do not contain mercury or lead. The material used for it becomes also as foam (foam) made of metal (e.g. Kupferoder aluminum foam) or as carbon foam (foam from leading ù:: : "" i ": 'where @ IL • • V 12909 2 carbon compounds -, Reticulated Vitreous CarbonRVC) “designates. Such a three-dimensional, porous foam becomes sometimes also as, sponge” bezeichnet.

With the employment of such electrodes however sufficient Stromund potential distribution, in particular with high current densities is to realize as well as the correct distribution of the gas /Fl üssigkeitsgemisches in the reactor not simply. In addition the question of the suitable current task seems not sufficiently solved into the porous materials. The constructional solution of the current task of the connection electrode in D into the porous material (e.g. Foam, sponge) and a suitable current distribution are however of crucial Bedeutung.

For the solution erfindungsgernäß of the task posed an electrode device is created, which is characterized by it that it covers a task electrode, a porous three-dimensional electrode and a means, that by contact the conduction between the task electrode and the porous three-dimensional electrode gewährleistet.

It was shown that with the electrode device according to invention electro-chemical conversions can be durchfiihren more rapidly in high yield. Beyond that high current densities of 2500 A/m2 and more leave themselves, e.g. 3000 A/m2 and more, erzielen.

A task electrode in an electrode in accordance with available invention covers usual task electrodes, e.g. Task electrodes, as they are usual in electro-chemical procedures. Usual task electrodes are generally two-dimensional. The task electrode consists either essentially of Metali/metallic oxides, e.g.

comprehensively and comprehensively a metal alloy, or from leading art-openly, or from leading carbon compounds, e.g. from graphite, glass carbon, or a leading carbon fiber composite material, prefers several different metals from leading Kohlefasern.

The use of dreidimenionaler, porous electrodes made of metal or from carbon in electro-chemical reactions, for example metal foam or carbon foam, is well-known. Carbon foam is e.g. in Gallego et al., carbon 41 (2003), p. 1461-1466 described. The porous material, which is used in accordance with available invention, exhibits prefers a high porosity and thus a high specific surface:

iq i, in ilol • V 12909 3 a preferential arrangement of the electrode device according to invention consists of the fact that is intended as means:

an electrically leading and ductile material, which is attached between the task electrode and the porous, three-dimensional electrode, - a Klebesehichte from conductive K.teber, with which the porous, three-dimensional electrode is glued to the task electrode, or - a fusion, a soldering or a welding of the porous, three-dimensional electrode with the Aufgabeelektrode.

Leading ones and ductile materials are admitting and close for example (leading) ductile Kohlenstoffolien or carbon felt (e), Metallfiklze, ductile metal foils/sheet metals, like KupferfolieiKupferblech, aluminum foil/aluminum plate and metal wool, like Kupferwotle, aluminum wool ein.

ù ductile " closes plastic and flexible ductility ein.

Conductive adhesives are admitting and include for example adhesives, pastes or cement masses from a mixture of graphite or metals and phenol, Epoxidoder Furanharz, those for example under the trade name Three bond 3301, available acquisitionable sind.

A fusion, a soldering or a welding of the porous, three-dimensional electrode with the task electrode can take place after a well-known fusion, Verlötungsoder Versehweißungsmethode, for example via local heating, joining in heat up condition and Abkühlung.

A further preferential arrangement of the electrode device according to invention consists of that the task electrode from a leading carbon compound in an educated manner ist.

Before-pulled the giving up electrode a leading carbon compound, to some Kohtenstofffitz and to it afterwards a carbon foam pressed sind.

Another preferred electrode device in accordance with available invention is characterized by it that it covers a task electrode from metal or metallic oxide, to the one ductile metal foil, a ductile Meta! lblech, a Metaltfilz or a metal wool and to it afterwards a metal foam pressed sind.

V 12909 4 the invention concerns also an electro-chemical cell, in that the anode and/or the cathode, in particular the cathode, an electrode device according to invention darstellt.

If the anode does not represent an electrode in accordance with available invention, is the anode prefers a dimension-stable anode (DSA), those from one or more metals, metallic oxides or of coated metals or metallic oxides, e.g. with metallic oxide coated metals made and for example available acquisitionable ist.

Furthermore the invention concerns the use of an electrode device or an electro-chemical cell in an electro-chemical procedure, in particular for the synthesis of chemical compounds, in particular for the production of L-Cystein from L-Cystin, or for the treatment of water or Abwasser.

In addition the invention concerns a procedure for the production of a chemical final product from a chemical output product in a electricalbefore-mixed cell, which is characterized by it, there, ss the conversion of the chemical output product at an electrode device according to invention in an electro-chemical cell according to invention erfolgt.

An electrode, or an electro-chemical cell in accordance with available invention fiär all purposes, in which electrodes are applicable, e.g. for the synthesis of chemical compound and to (off) wasserautbereitung, preferentially for the synthesis of chemical compounds, e.g. for the production of H2 02 by reduction of 02, production of Adiponitril can be used by Elektrohydrodimerisation of acrylonitrile, electrical reduction in ionischen liquids, production of 2-Methylindol, production of Glyoxylsäure, production of L-Cystein, e.g. for the production of L-Cystein from L-Cystin.

If an electro-chemical cell is used in accordance with available invention for the synthesis of chemical compounds, the output product and the final product are either in the Katholyten or in the anolyte. In a special Ausfiihrungsforrn of the available invention an ion exchanger diaphragm is separated, and in such a case exhibits an electro-chemical line in accordance with available invention a Kathodertraum and an anode region in an electro-chemical cell in accordance with available invention of the Katholyt from the anolyte by a diaphragm, in a special AusRihrung. In a Ausäihrungsform of the available invention an electro-chemical cell can in accordance with available invention to a Katholytbehälter and at i w • • m œlo “” 6 * °a • o o* i “t • V 12909 an anolyte container attached its. The Katholyt can be pumped from the Katholytbehälter by the cathode area of the cell and again back in the Katholytbehälter and the anolyte from the anolyte container by the cell and again back to the anolyte container, to the desired conversion degree of the parent compounds to the product reached ist.

For example it can proceeds for the production of a chemical final product from a chemical output product to be in such a manner implemented that - in a first, currentdriven phase, e.g. up to a conversion of approx. 90%, high Stromdiehten to be used and - in a second phase high Massenbzw. Stofttransport takes place, whereby high Massenbzw. Stoffla'ansport can take place e.g. via increased Umpumpen of the substrate kann.

In a further aspect of the available invention an electrode is used in accordance with available invention during the conversion from L-Cystin to the L-Cystein. As anode a dimension-stable anode (DSA) is preferably used and as cathode an electrode in accordance with available invention. For example for example a copper cathode finds or, preferential, a graphitic cathode use during the conversion from L-Cystin to L-Cystein as task electrode. The porous, three-dimensional electrode is prefers a carbon foam. In case of a conversion from L-Cystin to the L-Cystein is the anode prefers a dimensionsstabite anode from coated titanium, e.g. irdiumbeschichtetemn titanium. The Katholyt is separate by an ion exchanger diaphragm from the anolyte, whereby the output product and the final product are in the Katholyten (Kathodem'aum). In a preferential execution form the electro-chemical cell is attached to a Katholytbehälter and to an anolyte container. The Katholyt is pumped from the Katholytbehälter by the cathode area of the cell and again back in the Katholytbehälter and the anolyte is pumped from the anolyte container by the cell and again back to the anolyte container, to the desired conversion degree of the parent compounds to the product reached i st.

The procedure preferably in such a manner accomplished that in a first currentdriven phase a high electrical current density is used, preferably to a conversion of approx. 90% erricht is, and in a second phase, e.g. starting from a conversion of approx. 90%, high Massenbzw, material transfer takes place, e.g. by increased Umpumpen of the Substrats.

o nl ql # o • -, ol “#pa, • • • , i€ for each o t v 12909 6 in another aspect makes the available invention available a procedure for the production of L-Cystein from L-Cystin in an electro-chemical cell, which is characterized by the fact that the conversion of the L-Cystins at an electrode in an electro-chemical cell in accordance with available invention erfolgt.

The electro-chemical reaction takes place thereby in aqueous Medium.

For example thereby the procedure is led in such a manner that - in a first, currentdriven phase, e.g. up to a conversion of approx. 90%, high current densities to be used and - in a second phase high Massenbzw. Stofflransport stattfindet.

High Massenbzw. Material transfer can e.g. by increased Umpumpen of the substrate erfogen.

Via the two-piece guidance of the procedure the conversion takes place in the first phase predominantly at the task electrode and the conversion in the second phase predominantly at and/or in the porous, three-dimensional electrode, e.g. at and/or in the Carbonschaum.

The substrate covers thereby an aqueous mixture from output product and Endprodukt.

In a further aspect of the vodiegenden invention an electrode is begast in accordance with available invention in an electro-chemical cell, in order to increase the concentration from gases to, for the conversion necessarily sind.

A preferential execution form of the electrode device according to invention is schernatisch represented in the figure (Fig.) to 1 in form of an explosion representation. The electrode device 4 consists of a coal fiber board 3 as task electrode, to some ductile Kohtenstofffolie 2, e.g. carbon felt, and to it afterwards a Carbonsehaum 1 pressed ist.

In Fig. 4 is a photography of such a electrode device gezeigt.

In the following example the production of L-Cystein becomes still closer from L-Cystin by means of a Elektrodenvorriehtung according to invention beschrieben.

V 12909 ............. I:

• m • • : :: :: : : i • J tl “9 example the used electro-chemical cell according to invention is ot in the Fig. 1 schematically in form of an explosion representation gezeigt.

The cell contains a porous, three-dimensional cathode 1, which is appropriate in a plate (Spacer) 4 and which is connected to 3 with a seal plate 14 at a side by the task electrode (cathode), the one inlet 15 and a discharge opening 16 for the Katholyten, which contains the output product and after conversion also the final product, exhibits. Between the task electrode 3 and the seal plate 14 is a not leading intermediate plate 13. The plates 3a and 3b are inserted to the better sealing barness of the task electrode 3 between the not leading intermediate plate 13 and the plate 4. Between the task electrode 3 and the porous, three-dimensional cathode 1 carbon felt 2. the cell is enclosure furthermore a task electrode (anode) 8, those at a side with a plate 7 is connected and on the other side with a Absehlussplatte 10th between the task electrode 8 and the seal plate 10 is a not leading intermediate plate 9. the plates 8a and 8b to the better sealing barness of the Aut) gift electrode 8 between the not leading intermediate plate 9 and the plate 7 is inserted. Between the plates 5 and 7 is a diaphragm 6, the one crossing Ausgangsbzw. Final product from the cathode area, which is within the plates 4 and 13 into that the anode region, which is within the plates 7 and 9, prevented. Between the diaphragm 6 and the plate 4 is a Ansressplatte 5, which presses the porous, three-dimensional cathode 1 against the task electrode 3. In the plate 10 an inlet 11 and a discharge opening 12 for the anolyte are appropriate. By Einund the Katholyt knows discharge openings 11, 12, 15 and 16, and/or the anolyte with the help of a pump (not shown) umgepumpt werden.

At the task electrodes 3 and 8 is the positive, and/or negative Stromautgeber.

All flüssigkeitsfiährenden ranges are sealed (not shown). The entire device becomes by tighteners, preferably by bolt connections (not shown), zusammengehalten.

The reduction from L-Cystin to L-Cystein took place in aqueous medium with a Stromdiehte from 4000 A/m2, whereby as anode a dimension-stable anode was used. As cathode either a) became a copper electrode, which is covered with a spongy lead, in accordance with the state of the art, or o (, 1o tt mem # V 12909 8 b) an electrode of task of carbon fiber, which over carbon felt is pressed against a Carbonsehaum, in accordance with available invention used. The remaining test conditions were identisch.

It was found that in the comparison by conventional spongy lead with the electrode in accordance with available invention the product quality (purity of the received LCysteins more largely than 99%) is already reached with an electrode in accordance with available invention after 3,5 hours, while for the same product quality with an electrode in accordance with the state of the art 20 hours were necessary. The conversion with an electrode in accordance with available invention took place thus nearly 6 times so fast. See in addition Fig. 3:

In Fig. 3 shows the ungestrichelten lines the concentration of the L-Cystins in each case: The line, those, 210 " in the time axis ends represents the measured concentration in a procedure with an electrode in accordance with available invention; the ungestrichelte line, those, 1200 " in the time axis ends represents the measured concentration in a procedure with an electrode in accordance with the state of the art. At the terminator point the concentration of the Cystins amounted to 0.16 mol! m3, the conversion amounted to 99.97%, the time needed for it amounted to 3 hours, 30 Minuten.

The broken lines represent in each case the conversion. That broken line, those, 210 " in the time axis ends represents the measured conversion in a procedure with an electrode in accordance with available invention. The broken line, those, 1200 " in the time axis ends represents the measured concentration in a procedure with an electrode in accordance with the state of the art. At the terminator point the concentration of the Cystins amounted to 3.41 mol/m3, the conversion amounted to 99.5%, the time needed for it amounted to 20 Stunden.

The same achievement with an electrode can be achieved by the faster and effiziertteren conversion with an electrode in accordance with available invention in the comparison with an electrode in accordance with the state of the art in accordance with available invention in by far shorter time, what considerable Zeitund Energieeinspartmgen bedeutet.

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