MEMBRANELESS ELECTROLYSIS CELL AND USE THEREOF IN ELECTROLYSIS REACTIONS

Abstract

A membraneless electrolysis cell, which includes a solid body, the solid body having a central cavity, two housings, at least one secondary cavity, at least one duct for providing a material, two ducts for admitting two electrolyte flows, and at least one supply duct. The cell configuration allows a material, in particular a reagent, to be fed selectively to the anode or cathode, separate from the electrolyte flow.

Claims

1-23. (canceled)

24. A membraneless 3D electrolysis cell comprising: a solid body delimited by external faces, in particular at least 6 external faces, preferably including at least 4 lateral faces and 2 flat faces, upper and lower, and a porous anode, and a porous cathode, said solid body comprising: a central cavity, two housings, apical nd basal, at least one secondary cavity, at least one intake duct of material, two inflow ducts for two electrolyte flows, and at least one supply duct, wherein: said porous anode and said porous cathode are respectively contained in said apical and basal housings, each inflow duct or extends respectively from the central cavity through an orifice to an outer face of the solid body, in particular the external faces on which the two respective ducts open out being different and preferably opposite each other, the at least one intake duct extends from at least one secondary cavity to an outer face of the solid body, the at least one supply duct extends from at least one secondary cavity to the apical and/or basal housings, the said at least one intake duct is able of conducting a material from the outside of the solid body respectively to the at least one secondary cavity, the two inflow ducts are able to conduct an electrolyte from the outside of the solid body towards the central cavity and to introduce two electrolyte flows through the respective ends of the inflow ducts, said two inflow ducts are positioned so as to allow the two flows to meet in the central cavity and to cause a separation of each of the electrolyte flows, respectively into two parts, a first part of one of the flows and a first part of the other flow being conducted towards the anode, and a second part of one of the flows and a second part of the other flow being conducted towards the cathode, said at least one supply duct is able of conducting a material from the at least one secondary cavity to the apical housing or the basal housing containing respectively the anode and the cathode.

25. The electrolysis cell of claim 24, comprising: a solid body delimited by at least 6 external faces, including at least 4 lateral faces and 2 flat faces, upper and lower, and a porous anode, and a porous cathode, said solid body comprising: a central cavity, delimited by a lateral surface, forming an interface with said solid body, and by at least two edges, respectively apical and basal, forming the apical and basal ends of the central cavity, said central cavity being flanked, on either side of its apical and basal edges, by two housings, apical and basal, at least one secondary cavity, in particular in the shape of a torus, said at least one secondary cavity being located within a portion of the solid body, said portion of the solid body surrounding the central cavity, and being delimited by an outer lateral surface, forming an interface with said solid body, by an inner lateral surface constituted by the lateral surface of the central cavity, and by two surfaces, respectively apical and basal, said at least one secondary cavity being delimited by a surface forming an interface with the part of the solid body, said at least one secondary cavity at least partially surrounding the central cavity on a part of its lateral surface, said apical and basal housings each being delimited by a lateral surface, by at least one edge, and by a flat face forming an interface with said solid body, the edge of the apical housing being located in the plane of the upper flat face of the solid body, the edge of the basal housing being located in the plane of the lower flat face of the solid body, said flat face being parallel to the two flat faces, upper and lower, of the solid body and formed by the surface of the part of the secondary cavity and by one end of the secondary cavity, the flat face of the apical housing being formed by the apical surface of the solid body part and by the apical end of the central cavity, the flat face of the basal housing being formed by the basal surface of the solid body part and by the basal end of the central cavity, at least one intake duct of material, two inflow ducts for two electrolyte flows, and at least one supply duct, wherein: said porous anode and said porous cathode are respectively contained in said apical and basal housings, each inflow duct or extends respectively on either side of the central cavity, from a zone of said surface, to a lateral face of the solid body, the faces on which the two respective ducts open out being different and preferably opposite each other, said inflow ducts forming two cell inlets, the at least one intake duct extends from an outer lateral zone of the surface of the at least one secondary cavity to a lateral face of the solid body, the at least one intake duct forming at least a third inlet to the cell, the at least one supply duct, starts from a zone of the apical surface and/or from a zone of the basal surface of the surface of the secondary cavity, and opens out on said apical and/or basal housings, via the flat faces of the said housings, and via the apical and/or basal surface of the part of the solid body, the said at least one intake duct is able of conducting a material from the outside of the solid body respectively to the at least one secondary cavity, the two inflow ducts are able to conduct an electrolyte from the outside of the solid body towards the central cavity, said at least one supply duct is able to conduct a material from the at least one secondary cavity towards the apical housing or the basal housing.

26. The electrolysis cell according to claim 24, wherein said solid body is in the shape of a parallelepiped, and is in particular in the shape of a cube, and/or wherein the central cavity is substantially in a cylindrical shape, and is in particular in the shape of a cylinder, or is in the shape of a hexagonal prism.

27. The electrolysis cell according to claim 24, comprising four secondary cavities, each secondary cavity being in particular in the shape of a half-torus with an oval or circular cross-section, or comprising two secondary cavities, each secondary cavity being in particular in the shape of a torus with an oval or circular cross-section, or comprising a secondary cavity, in particular in the shape of a torus with an oval or circular cross-section.

28. The electrolysis cell according to claim 24, comprising: a central cavity in the shape of a cylinder, four secondary cavities, each secondary cavity being in the shape of a half-tore with an oval or circular cross-section, two of said four secondary cavities being connected to the apical housing by a supply duct, and two of said four secondary cavities being connected to the basal housing by a supply duct, 4 intake ducts, each intake duct extending from one of the four secondary cavities, two inflow ducts, said inflow ducts extend respectively from the central cavity, one opposite the other, and are at substantially the same distance from the apical end and from the basal end of said central cavity.

29. The electrolysis cell according to claim 24, wherein said solid body comprises or consists of a mechanically resistant and chemically inert material, in particular suitable for transporting gases and/or organic solvents.

30. The electrolysis cell according to claim 24, wherein the solid body comprises or consists of a material chosen from: Polypropylene (PP), polyethylene (PE), polyvinyl chloride (PVC), polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), acrylonitrile butadiene styrene (ABS), polyoxymethylene (POM), polyhexamethylene adipamide, an acrylic or metacrylic polymer, in particular a photopolymerisable resin such as polymethyl methacrylate (PMMA), or polymers derived from acrylate, urethane dimethacrylate or bisphenol A dimethylacrylate, non-conductive composite materials such as ceramic materials, or mixtures of fibreglass and a resin, said material being optionally reinforced with carbon fibres.

31. The electrolysis cell according to claim 24, wherein the porous cathode and/or anode have a theoretical porosity P.sub.t from 60 to 80%, in particular from 70 to 75%, in particular around 73%.

32. The electrolysis cell according to claim 24, wherein the distance between the cathode and the anode is from 1 to 6 mm, or less than 1 mm, in particular from 0.1 to 1 mm.

33. The electrolysis cell according to claim 24, wherein the porous cathode and/or anode consists of a mixture of: carbon black, an ionic polymer, optionally a catalyst, and optionally polytetrafluoroethylene (PTFE).

34. The electrolysis cell according to claim 24, further comprising two gaskets, in particular having a thickness of from 0.2 to 1.0 mm,

35. The electrolysis cell according to claim 24, further comprising two closing plates.

36. The electrolysis cell according to claim 24, further comprising two current collectors, in particular integrated in the closing plates, said gaskets and closing plates being secured to the solid body via at least one mounting hole.

37. A method of manufacturing an electrolysis cell according to claim 24, said method comprising the preparation of the solid body, wherein said preparation of the solid body comprises the following steps: a 3D printing step A to obtain a raw solid body, a washing step B to obtain a washed solid body, and optionally a step C for polishing said washed solid body.

38. An electrolysis process, the process comprising: a step 1 of introducing two flows of electrolyte through the inflow ducts into an electrolysis cell according to claim 24, the two flows being directed in opposite directions, a step 2 of providing a material into said electrolysis cell via the at least one intake duct, a step 3 of applying a potential difference between the cathode and the anode, in particular 5V, causing an electrolysis reaction, in particular of the material provided by the at least one intake duct.

39. The electrolysis process according to claim 38, wherein the material provided in step 2 is selected from: a reactive gas, chosen in particular from ethylene, CO.sub.2, CO, O.sub.2, a reactive liquid, in particular selected from H.sub.2O, an alcohol, in particular methanol or ethanol, or formic acid, a solution comprising a reagent, an inert gas, in particular nitrogen, a coolant or heat transfer fluid.

40. The electrolysis process according to claim 38, the process comprising: a step 1 of introducing two electrolyte flows through the inflow ducts into the electrolysis cell, the two flows being directed in opposite directions, a step 2 of providing a material into said electrolysis cell via the at least one intake duct, a step 3 of applying a potential difference between the cathode and the anode, in particular 5V, causing an electrolysis reaction of the material provided by the at least one intake duct, the material provided in step 2 is chosen from: a reactive gas, chosen in particular from ethylene, CO.sub.2, CO, O.sub.2, a reactive liquid, in particular selected from H.sub.2O, an alcohol, in particular methanol or ethanol, or formic acid, a solution comprising a reagent, wherein the electrolyte flow does not include the material provided in step 2.

41. The electrolysis process according to claim 38, wherein the material provided to step 2 is a reactive gas, in particular chosen from ethylene, CO.sub.2, CO, O.sub.2.

42. The electrolysis process according to claim 38, the process comprising: a step 1 of introducing two electrolyte flows through the inflow ducts into the electrolysis cell, the two flows being directed in opposite directions, a step 2 of providing a material into said electrolysis cell via the at least one intake duct, a step 3 of applying a potential difference between the cathode and the anode, in particular 5V, causing an electrolysis reaction of a material contained in the electrolyte flows, the material provided in step 2 is chosen from a cooling liquid, a heat transfer liquid or an inert gas, in particular nitrogen.

43. The electrolysis process according to claim 38, wherein the electrolysis is a reduction reaction of CO.sub.2 to CO, said process comprising the following steps of: introducing electrolyte flows, in particular a 0.5 M aqueous sodium bicarbonate solution, via said inflow ducts, then providing CO.sub.2 to the cathode via the at least one intake duct, then applying a potential difference, in particular 5V, between the cathode and the anode, then, recovering the CO formed at the cathode, wherein the process optionally comprises providing a material to the anode, via the intake ducts, said material being in particular a material that can be oxidised at the anode, and wherein at least two electrolysis cells are used in parallel or in series.

Description

[0426] The following examples and Figures illustrate the invention, without limiting its scope.

[0427] FIGS. 1 to 8 show an electrolysis cell comprising a solid body (1) containing 4 intake ducts (5). 2 of the said 4 intake ducts (5) can selectively provide a material to the cathode, through a first secondary cavity (2), and 2 of the said intake ducts (5) can selectively provide a material to the anode, through a second secondary cavity (2).

[0428] FIGS. 9 to 13 show an electrolysis cell comprising a solid body (1) containing 2 intake ducts (5). The said 2 intake ducts (5) separate into 2 inside the solid body (1), to form 2 new ducts for each intake duct (5). The solid body (1) in this embodiment comprises 2 secondary cavities (2) through which the material flows to the cathode and the anode.

[0429] FIG. 1 shows a transparent solid body 1, seen from above, on one of the flat faces B of said solid body.

[0430] 2 represents the location of the central cavity, 3 and 4 represent the location of the apical housing 3 and basal housing 4, 1 represents the part of the solid body comprising at least one of the secondary cavities, 6/7 represent the inflow ducts for the countercurrent electrolyte flows, 5 represents the intake ducts for adding material, 9 represents the mounting holes intended for assembling the separate parts of the cell, in particular the gaskets and the closing plates, 81 represents the orifices allowing the electrolyte flows to enter the solid body, 83 represents the orifices allowing the material flows to enter the solid body, 86 represents the orifices allowing the material flows to enter a housing.

[0431] FIG. 2 shows cross-sections of solid body 1 along the Y axis. FIG. 2A shows a transparent solid body 1, seen from above, on one of the flat faces B of said solid body. FIG. 2B shows a top view of one of the flat surfaces B. FIG. 2C is a perspective view, showing the inside of the solid body. FIG. 2D is a front cross-sectional view of the solid body.

[0432] 1 represents the part of the solid body comprising the at least one secondary cavity, 2 represents the secondary cavities, 3 and 4 represent the apical housing 3 and basal housing 4, 5 represents the material intake ducts, 81 represents the orifices allowing the electrolyte flows to enter the solid body, 82 represents the orifices enabling electrolyte flows to enter the central cavity, 83 represents the orifices enabling material flows to enter the solid body, 86 represents the orifices enabling material flows to enter a housing, B represents one of the flat faces of the solid body.

[0433] FIG. 3 shows cross-sections of solid body 1 along axis X. FIG. 3A shows a transparent solid body 1, seen from above, on one of the flat faces B of said solid body. FIG. 3B shows a top view of one of the flat surfaces B. FIG. 3C is a perspective view, showing the inside of the solid body. FIG. 3D is a front cross-sectional view of the solid body.

[0434] 2 represents the central cavity, 2 represents the secondary cavities, 3 and 4 represent the apical housing 3 and the basal housing 4, 6/7 represent the inflow ducts for the countercurrent electrolyte flows, 81 represents the orifices allowing the electrolyte flows to enter the solid body, D represents an edge of the central cavity, C represents the lateral surface of the central cavity, F represents the inner lateral surface of part 1 of the solid body, G represents the apical surface of part 1 of the solid body.

[0435] FIG. 4 shows median sections of the solid body 1, along a diagonal axis XY, at 45 to the X and Y axes. FIG. 4A shows a transparent solid body 1, seen from above, on one of the flat faces B of said solid body. FIG. 4B shows a top view of one of the flat faces B. FIG. 4C is a perspective view, showing the inside of the solid body. FIG. 4D shows a front section view of the solid body along the Y axis.

[0436] 5 represents the material intake ducts, 81 represents an orifice allowing electrolyte flows to enter the solid body, 82 represents the orifices allowing electrolyte flows to enter the central cavity, I represents the lateral surface of the apical housing 3, J represents the edge of the apical housing 3, K represents the flat face of the apical housing 3.

[0437] FIG. 5 shows cross-sections of the solid body 1 along the Z axis. FIG. 5A shows the sectional plane as seen from a first side face A of the said solid body. FIG. 5B shows the section as seen from a second side face A of the said solid body, the second side face being at an angle of approximately 90 to the first side face. FIG. 5C shows a section as defined above for FIG. 5A, highlighting the interior of the solid body. FIG. 5D shows a section as defined above for FIG. 5B, highlighting the interior of the solid body.

[0438] 2 represents the central cavity, 2 represents the secondary cavities, 5 represents the material intake duct, 81 represents the orifices enabling electrolyte flows to enter the solid body, 82 represents the orifices enabling electrolyte flows to enter the central cavity, 83 represents the orifices enabling material flows to enter the solid body, 84 represents the orifices enabling material flows to enter a secondary cavity 2, A represents one of the side faces of the solid body.

[0439] FIG. 6 shows cross-sections of the solid body 1, along the Z axis, which has been rotated by 90 with respect to the cross-section in FIG. 5. FIG. 6A shows the cross-section as seen from a first side face A of the said solid body. FIG. 6B shows the section as seen from a second side face A of the said solid body, the second side face being at an angle of approximately 90 to the first side face. FIG. 6C shows a section as defined above for FIG. 6A, highlighting the interior of the solid body. FIG. 6D shows a section as defined above for FIG. 6B, highlighting the interior of the solid body.

[0440] 5 represents the material intake ducts, 6/7 represent the inflow ducts for the countercurrent electrolyte flows, 81 represents the orifices allowing the electrolyte flows to enter the solid body, 82 represents the orifices allowing the electrolyte flows to enter the central cavity, 83 represents the orifices allowing the material flows to enter the solid body, 84 represents the orifices allowing the material flows to enter a secondary cavity 2.

[0441] FIG. 7 shows the symmetry of the solid body. FIG. 7A is a perspective view showing the interior of solid body 1 along a diagonal axis at 45 to the X and Y axes. The intersection of the two axes a and a corresponds to the point of symmetry i of the solid body. FIG. 7B shows a top view of one of the flat faces B of said solid body. The intersection of the two axes a and a corresponds to the point of symmetry i of the solid body.

[0442] FIG. 8 shows an assembled electrolysis cell comprising a solid body as defined in FIGS. 1 to 7.

[0443] FIG. 9 is constituted by FIG. 9A and FIG. 9B, which show external perspective views of a solid body 1.

[0444] 2 represents the location of the central cavity, 3 represents the apical housing, 9 represents the mounting holes intended for assembling the separate parts of the cell, namely in particular the gaskets and the closing plates, 81 represents the orifices allowing the electrolyte flows to enter the solid body, 83 represents the orifices allowing the material flows to enter the solid body, 86 represents the orifices allowing the material flows to enter a housing, B represents one of the 2 flat faces of the said solid body. A represents a side face of the solid body.

[0445] FIG. 10 shows a solid body 1, seen from above, on one of the flat faces B of said solid body. 2 represents the location of the central cavity, 9 represents the mounting holes intended for assembling the individual parts of the cell, in particular the gaskets and the closing plates, 86 represents the orifices allowing material flows to enter a housing.

[0446] FIG. 11 shows cross-sections of the solid body 1 along the Z axis. FIG. 11A shows the cross-sectional plane as seen from a first side face A of the said solid body. FIG. 11B shows a section as defined above for FIG. 11A, highlighting the interior of the solid body. FIG. 11C shows a perspective view of the cross-section shown in FIG. 11B.

[0447] 2 represents the location of the central cavity, 1 represents the part of the solid body comprising at least one of the secondary cavities, 6/7 represent the inflow ducts for the countercurrent electrolyte flows, 5 represents the material intake ducts, 9 represents the mounting holes intended for assembling the individual parts of the cell, namely in particular the gaskets and the closing plates, 81 represents the orifices allowing electrolyte flows to enter the solid body, 82 represents the orifices allowing electrolyte flows to enter the central cavity, 83 represents the orifices allowing material flows to enter the solid body, 84 represents the orifices allowing material flows to enter a secondary cavity 2, 86 represents the orifices allowing material flows to enter a housing.

[0448] FIG. 12 shows cross-sections of solid body 1 along axis X. FIG. 12A shows a solid body 1, seen from above, on one of the flat faces B of said solid body. FIG. 12B shows a front cross-section of the solid body. FIG. 12C is a perspective view, showing the inside of the solid body.

[0449] 2 represents the central cavity, 2 represents the secondary cavities, 3/4 represents the housings, 9 represents the mounting holes for assembling the individual parts of the cell, in particular the gaskets and the closing plates, 82 represents the orifices allowing electrolyte flows to enter the central cavity, 86 represents the orifices allowing material flows to enter a housing.

[0450] FIG. 13 shows an electrolysis cell and some individual parts. a represents the electrolysis cell, 1 represents the solid body, 11 represents two closing plates, 10 represents a gasket, 9 and 9 represent mounting holes for respectively the gaskets and closing plates, 3 and 3 represent holes for accommodating the electrodes of respectively the gaskets and closing plates, M represents the flat faces of the closing plates, N represents the side faces of the closing plates, L represents the flat faces of the gaskets, 12 represents a current collector.

[0451] FIG. 14 shows a diagram of the electrolyte and material flows within the solid body. 6/7 represent the 2 inflow ducts for the countercurrent electrolyte flows, 5 represents all 4 material intake ducts, 3/4 represent the housings respectively containing the cathode and anode. The diamond I represents the point where the two electrolyte flows separate and flow towards the anode and cathode.

[0452] FIG. 15 shows a schematic representation of the cavities.

[0453] FIG. 15A shows a cylindrical central cavity 2, surrounded by two secondary cavities 2 in the shape of a half torus with a circular cross-section.

[0454] FIG. 15B shows a central cavity 2 in the shape of a hexagonal prism, surrounded by two secondary cavities 2 in the shape of a half torus with a circular cross-section, presenting angles.

[0455] FIG. 16 shows different geometric shapes of secondary cavities 2.

[0456] FIG. 16A shows a secondary cavity in the shape of a torus with a circular cross-section, seen from above, FIG. 16B shows a perspective view of a secondary cavity in the shape of a torus with a rectangular cross-section, FIG. 16C shows a perspective view of a secondary cavity in the shape of a torus with a circular cross-section, FIG. 16D shows a perspective view of a secondary cavity in the shape of a torus with a rectangular cross-section, FIG. 16E shows a cross-section of a circular cross-section of the secondary cavity of FIG. 16C, highlighting the various surfaces H FIG. 16F shows a cross-section of an oval cross-section of a secondary cavity in the shape of a torus with an oval cross-section, highlighting the various surfaces H,

[0457] H represents the apical and basal surfaces, H represents the outer lateral surface, H represents the inner lateral surface, 85 represents the orifices allowing material flows to leave the secondary cavity 2.

[0458] FIG. 17] represents an experimental installation for using an electrolysis cell according to the invention. a represents the electrolysis cell, b represents a pump, c represents a tank containing an electrolyte, d represents a catholyte collection tank, e represents an anolyte collection tank, f represents a current source, g represents a cylinder containing a reagent, in particular a reactive gas, h represents a rotameter.

[0459] FIG. 18 shows an experimental installation using an electrolysis cell according to the invention, in which several cells have been placed in series. The term DC power supply is used to mean direct current power supply.

[0460] FIG. 19 shows an experimental installation using an electrolysis cell according to the invention, in which several cells have been placed in parallel. The term DC power supply is used to mean direct current power supply.

[0461] FIG. 20 shows a chronoamperogram obtained according to example 5, with the time expressed in seconds on the abscissa and the current expressed in Amperes on the ordinate.

[0462] FIG. 21 shows a chromatogram obtained according to example 5 with the time expressed in minutes on the abscissa and the absorbance expressed in Absorbance Units AU on the ordinate.

[0463] FIG. 22 shows a part used to prevent a material from reaching the electrodes, said part allowing the material flow to be switched to a temperature management circuit. FIGS. 22A and 22B show the two front views and FIG. 22C shows a perspective view of the said part. O represents a protuberance used to plug the orifices 85, present on part 1 of the central cavity, P represents notches used to circulate the material in two secondary cavities.

Abbreviations

[0464] SLA stereolithography [0465] EPDM ethylene-propylene-diene monomer [0466] PMMA polymethyl methacrylate . . . . [0467] PP polypropylene [0468] PU polyurethane [0469] PTFE polytetrafluoroethylene, Teflon, polytetrafluoroethylene, Teflon [0470] GC Gas chromatography [0471] TCD thermal conductivity detector

EXAMPLES

Example 1Preparation of the Solid

[0472] The body of the cell was manufactured using a 3D printer (Formlabs, Form 2), employing SLA (stereolithography) technology. The material used was a methacrylic acid-based photopolymerisable resin, which was polymerised under UV irradiation at 405 nm. The 3D files were obtained using 3D modelling software Fusion 360 version 2.0.10564.

[0473] The various parts were designed by extruding the faces of a 2D blank. The various cavities were obtained by subtracting the desired shapes (shapes previously generated).

[0474] After printing, the body was placed in a sonication bath containing isopropanol, then sonicated for 15 minutes. The cavities were thus emptied of unpolymerised resin residues, then the isopropanol solvent was evaporated using a compressed air jet. The body was washed a second time by sonication in isopropanol, then treated for 20 minutes under UV at 405 nm to ensure complete polymerisation of the resin.

[0475] The threaded holes for the pipe adapters were then drilled and tapped by hand.

Example 2Preparing Spare Parts and Assembling the Cell

[0476] Laser cutting was used to produce the joints and the outer plates.

[0477] The parts were designed in 2D using Fusion 360 software version 2.0.10564, then cut from different materials (EPDM or silicone for the gaskets and PMMA for the outer plates). The outer plates were also obtained by 3D printing.

Example 3Preparation of a Cathodic Electrode for the Reduction of CO.SUB.2 .to CO

[0478] A 1:1 mixture by weight of carbon black (500 mg) and cobalt phthalocyanine (500 mg) was suspended by sonication in ethanol (50 ml), then PTFE (10 mg) and Nafion (10 mg) were added to the suspension. The suspension was then evaporated under vacuum to give a material in powder form. The powdered material was then converted into an electrode by two methods: [0479] Method 1: A paste was formed by adding a small quantity of ethylene glycol (0.1 to 15 ml). The paste was placed in a mould and the solvent was evaporated by heating. [0480] Method 2: the powder was pressed using a manual press, the pallet (contained in the press) was then heated to 90 C. for 3 hours.

Example 4Preparation of a Cathodic Electrode for the Reduction of H.SUB.2 .O to H.SUB.2

[0481] An electrode was prepared according to the procedure in Example 3, replacing the cobalt phthalocyanine with platinum.

Example 5Preparation of an Anodic Electrode for an Oxidative Carbonylation Reaction

[0482] 200 mg HAuCl, 250 mg Vulcan XC72r powder and 500 mL ultrapure water* are placed in an Erlenmeyer flask. A bar magnet was inserted into the Erlenmeyer flask, along with an ultrasound probe. The mixture was sonicated overnight (67.5 W) with stirring. The solution was transferred to a flask and the solvent evaporated. The powder obtained is compressed in a mould to obtain the desired shape of the anodic electrode.

[0483] *Ultrapure water can be replaced by ethanol or methanol. 100 to 500 mg of PTFE and/or 5 to 500 mg of an ionomer can also be added.

Example 6CO.SUB.2 .Reduction Reaction to CO

[0484] The electrolysis cell shown in FIGS. 9 to 13 was used in a reaction to reduce CO.sub.2 to CO. The electrode prepared according to Example 3 was used as the cathode.

[0485] Chronoamperometry was performed by applying a potential bias of 5 V between the anode and cathode for 650 seconds (FIG. 20). CO.sub.2 was supplied at a flow rate of 0.4 l.Math.min.sup.1 and the electrolyte consisting of 0.5 M NaHCO.sub.3 was circulated through the system at a flow rate of 48 mL.Math.min.sup.1. A sample of the gas produced was examined by GC fitted with a TCD detector (FIG. 21), showing the presence of CO (1.37 min) as the only electrolysis product (the peak at 1.31 corresponds to air). The catalytic current observed was 36 mA.Math.cm.sup.2.

Example 7CO.SUB.2 .Reduction Reaction to CO

[0486] The electrolysis cell shown in FIGS. 1 to 8 was used in a reaction to reduce CO.sub.2 to CO. The electrode prepared according to Example 3 was used as the cathode.

[0487] Chronoamperometry was performed by applying a potential bias of 5 V between the anode and cathode for 650 seconds. CO.sub.2 was supplied at a flow rate of 0.4 l.Math.min.sup.1 and the electrolyte consisting of 0.5 M NaHCO.sub.3 was circulated through the system at a flow rate of 48 mL.Math.min.sup.1.

[0488] A sample of the gas produced was examined by GC fitted with a TCD detector, showing the presence of CO (1.37 min) as the only electrolysis product. The observed catalytic current was 100 mA.Math.cm.sup.2.

Example 8Oxidative Carbonylation Reaction

[0489] The electrolysis cell according to FIGS. 1 to 8 is used in a carbonylation reaction. The electrolyser is configured with an anode according to example 5 (or another cathode and/or anode described in the present application).

[0490] An electrolyte composed of methanol and a salt (sodium perchlorate) is circulated in the cell by pumps through the central cavity.

[0491] The secondary cavities supply CO to the anode. A potential bias of 5V is applied between the cathode and the anode.

[0492] The electrolyte, unreacted reagents and reaction products, i.e. dimethyl carbonate, are recovered in gas separators, and the gases are then purified using a membrane.

Example 9CO.SUB.2 .Reduction Reaction to CO at the Cathode and Oxidative Carbonylation at the Anode

[0493] The electrolysis cell according to FIGS. 1 to 8 is used. The electrolyser is configured with a cathode according to example 3 and an anode according to example 5 (or another cathode and/or anode described in the present application).

[0494] An electrolyte composed of methanol and a salt (sodium perchlorate) is circulated in the cell by pumps through the central cavity.

[0495] The secondary cavities supply CO.sub.2 to the cathode and CO to the anode. A potential bias of 5V is applied between the cathode and the anode.

[0496] The electrolyte, unreacted reagents and reaction products are recovered in gas separators, and the gases are then purified using a membrane.