A three-compartment electrolytic cell for the production of alkali metal alkoxides.

Abstract

The invention relates in a first aspect to an electrolytic cell having three compartments, the intermediate compartment being separated from the cathode compartment by a cation-permeable solid electrolyte, e.g. NaSICON, and from the anode compartment by a diffusion barrier. The present invention is characterized in that the intermediate chamber comprises an internal structure. The electrolytic cell of the present invention solves the problem that a concentration gradient is formed in the intermediate chamber of the electrolytic cell during electrolysis, causing a local drop in pH value and leading to damage to the solid electrolyte. The internal structure generates a vortex when the electrolyte passes through the intermediate chamber during electrolysis, thereby preventing the formation of a pH gradient. In a second aspect, the present invention relates to a method for producing an alkali metal alkoxide solution in an electrolytic cell according to the present invention.

Description

[Technical field]

[0001] The invention relates in a first aspect to an electrolytic cell having three compartments, the intermediate compartment being separated from the cathode compartment by a cation-permeable solid electrolyte, e.g. NaSICON, and from the anode compartment by a diffusion barrier. The present invention is characterized in that the intermediate chamber comprises an internal structure. The electrolytic cell of the present invention solves the problem that a concentration gradient is formed in the intermediate chamber of the electrolytic cell during electrolysis, causing a local drop in pH value and leading to damage to the solid electrolyte. The internal structure generates a vortex when the electrolyte passes through the intermediate chamber during electrolysis, thereby preventing the formation of a pH gradient. In a second aspect, the present invention relates to a method for producing an alkali metal alkoxide solution in an electrolytic cell according to the present invention. [Background technology]

[0002] 1. Background of the invention The electrochemical production of alkali metal alkoxide solutions is an important industrial process and is described, for example, in DE 10360758 A1, US 2006 / 0226022 A1 and WO 2005 / 059205 A1. The principle of these processes is reflected in electrolytic cells in which a solution of an alkali metal salt, for example sodium chloride or NaOH, is present in the anode chamber, and an alcohol solution containing the alcohol or the alkali metal alkoxide in question in low concentration, for example sodium methoxide or sodium ethoxide, is present in the cathode chamber. The cathode and anode chambers are separated by a ceramic that conducts the alkali metal ions used, for example NaSICON or analogues of potassium or lithium. When a current is applied, chlorine is formed at the anode when chloride salts of the alkali metal are used, and hydrogen and alkoxide ions are formed at the cathode. The charge balance is maintained by the migration of the alkali metal ions from the intermediate chamber to the cathode chamber via a ceramic that is selective for them. Charge balance between the intermediate and anodic compartments is maintained by the migration of cations if a cation exchange membrane is used, or anions if an anion exchange membrane is used, or of both ion types if a nonspecific diffusion barrier is used, resulting in an increase in the alkali metal alkoxide concentration in the catholyte compartment and a decrease in the sodium ion concentration in the anolyte.

[0003] NaSICON solid electrolytes are also used in the electrochemical production of other compounds.

[0004] WO 2014 / 008410 describes an electrolytic process for producing elemental titanium or rare earths. The principle of the process is to generate titanium chloride from TiO2 and the corresponding acid, which is reacted with sodium alkoxide to obtain titanium alkoxide and NaCl, and finally electrolyzed to elemental titanium and sodium alkoxide.

[0005] WO 2007 / 082092 and WO 2009 / 059315 describe a process for the production of biodiesel in which triglycerides are first converted with the aid of electrolytically generated alkoxides using NaSICON to the corresponding alkali metal triglycerides, which are reacted in a second step with electrolytically generated protons to give glycerol and the respective alkali metal hydroxide.

[0006] Thus, the prior art describes processes carried out in electrolytic cells with ion-permeable layers, for example NaSICON solid electrolytes. However, these solid electrolytes usually suffer from the drawback of lacking long-term stability towards aqueous acids. This presents a challenge in that during electrolysis in the anode chamber, the pH drops as a result of oxidation processes (e.g. disproportionation or oxygen production to produce halogens). These acidic conditions attack the NaSICON solid electrolyte to such an extent that the process cannot be used on an industrial scale. To address this challenge, different approaches have been described in the prior art.

[0007] For example, three-compartment cells have been proposed in the prior art and are known in the field of electrodialysis, for example in US Pat. No. 6,221,225.

[0008] For example, WO 2012 / 048032 and US 2010 / 0044242 describe electrochemical processes for preparing sodium hypochlorite and similar chlorine compounds in such three-compartment cells. The cathode and intermediate compartments of the cell are separated by a cation-permeable solid electrolyte, e.g. NaSICON. To protect it from the acidic anolyte, the intermediate compartment is supplied with a solution, e.g., from the cathode compartment. US 2010 / 0044242 also describes in FIG. 6 the possibility of mixing the solution from the intermediate compartment with the solution from the anode compartment outside the compartments to obtain sodium hypochlorite.

[0009] Such cells have also been proposed in the prior art for producing or purifying alkali metal alkoxides.

[0010] For example, US Patent No. 5,389,211 describes a method for purifying an alkoxide solution using a three-compartment cell in which the compartments are separated from each other by a cation-selective solid electrolyte or a non-ionic partition. The intermediate compartment is used as a buffer compartment to prevent the purified alkoxide or hydroxide solution from the cathode compartment from mixing with the contaminating solution from the anode compartment.

[0011] DE 42 33 191 A1 describes the electrolytic recovery of alkoxides from salts and alkoxides in multi-compartment cells and stacks of multiple cells.

[0012] WO 2008 / 076327 describes a method for producing alkali metal alkoxides. It uses a three-compartment cell, the middle compartment of which is filled with alkali metal alkoxide (see, for example, paragraphs

[0008] and

[0067] of WO 2008 / 076327). This protects the solid electrolyte separating the middle compartment from the cathode compartment from the solution present in the anode compartment, which becomes more acidic in the course of electrolysis. A similar arrangement is described in WO 2009 / 073062. However, this arrangement has the disadvantage that the alkali metal alkoxide solution, which is the desired product, is consumed and is continually contaminated as a buffer solution. A further disadvantage of the process described in WO 2008 / 076327 is that the production of the alkoxide in the cathode compartment depends on the diffusion rate of the alkali metal ions through the two membranes or solid electrolytes. This in turn leads to a slowdown in the production of the alkoxide.

[0013] Further problems arise from the geometry of three-compartment cells, where the middle compartment is separated from the anode compartment by a diffusion barrier and from the cathode compartment by an ionically conductive ceramic. This inevitably leads to the development of a pH gradient and dead volumes during electrolysis. This can damage the ionically conductive ceramic, thereby increasing the voltage required for electrolysis and / or leading to ceramic breakage.

[0014] This effect occurs throughout the electrolytic cell, but the drop in pH is especially severe in the intermediate chamber because it is bounded by an ionically conductive ceramic. Gases are typically produced at the anode and cathode, and at least some mixing occurs in these chambers. In contrast, no such mixing occurs in the intermediate chamber, in which a pH gradient develops. This undesirable effect is exacerbated by the fact that the pumped brine generally moves through the electrolytic cell relatively slowly. [Prior art documents] [Patent documents]

[0015] [Patent Document 1] DE 10360758 A1 [Patent Document 2] US Patent Application Publication No. 2006 / 0226022 [Patent Document 3] International Publication No. 2005 / 059205 Brochure [Patent Document 4] International Publication No. 2014 / 008410 Brochure [Patent Document 5] International Publication No. 2007 / 082092 Brochure [Patent Document 6] International Publication No. 2009 / 059315 Brochure [Patent Document 7] U.S. Patent No. 6,221,225 [Patent Document 8] International Publication No. 2012 / 048032 Brochure [Patent Document 9] US Patent Application Publication No. 2010 / 0044242 [Patent Document 10] U.S. Pat. No. 5,389,211 [Patent Document 11] DE 4233191 A1 [Patent Document 12] International Publication No. 2008 / 076327 Brochure [Patent Document 13] International Publication No. 2009 / 073062 Brochure Summary of the Invention [Problem to be solved by the invention]

[0016] It was therefore an object of the present invention to provide an improved process for the electrolytic preparation of alkali metal alkoxides, and an electrolysis chamber particularly suitable for such a process, which do not have the abovementioned drawbacks and which in particular ensure an improved protection of the solid electrolyte before the pH gradient is formed and a saving in the use of reactants compared to the prior art. [Means for solving the problem]

[0017] 2. Brief description of the invention Surprisingly, what has now been discovered is an electrolytic cell and process that solves the problem addressed by the present invention.

[0018] In a first embodiment of the present invention, electrolytic cell E <100> At least one anode chamber K A <101> and at least one cathode chamber K K <102> and at least one intermediate chamber K M <103> And, K A <101> is the anode electrode E A <104> And Exit A KA <106> And, K K <102> is the cathode electrode E K <105> And, Entrance Z KK <107> And Exit AKK <109> And, K M <103> is the entrance Z KM <108> Diffusion barrier D <110> By K A <101> Partitioned from the alkali metal cation conducting solid electrolyte F K <111> By K K <102> Separated from K M <103> and K. A <101> is K M <103> From K A <101> Connection V that can send liquid to AM <112> are connected to each other by Intermediate room K M <103> is the internal structure <120> Equipped with an internal structure <120> is the intermediate chamber K M <103> Electrolyte L3 passing through <114> The present invention is configured to provide turbulence and vortices in the

[0019] In a second aspect, the present invention provides a method for producing a composition comprising the steps of: Electrolytic cell E according to the first aspect of the invention <100> In the solution of alkali metal alkoxide XOR in alcohol ROH L1 <115> A method for generating Concurrently: (a) Solution L2 containing alcohol ROH <113> K K <102> The process of passing (b) A neutral or alkaline aqueous solution L3 of a salt S containing X as a cation <114> K M <103> Then through V AM <112> Via K A <101> The process of passing (c)E A <104> and E K <105> applying a voltage between Including, This allows Exit A KK <109> 2, L2 <113> Solution L1 has a higher concentration of XOR than <115> Supplying Exit A KA<106> 2, L3 <114> Aqueous solution of S with a lower concentration of S than L4 <116> Supplying The present invention relates to a method in which X is an alkali metal cation and R is an alkyl group having 1 to 4 carbon atoms. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1 shows an electrolytic cell according to the invention. <100> and a preferred embodiment of the method according to the invention. [Diagram 2] FIG. 2 shows a further embodiment of an electrolytic cell according to the invention and a method according to the invention corresponding to the one shown in FIG.

[0021] FIG. 1 shows an electrolytic cell according to the invention. <100> and a preferred embodiment of the method according to the invention. <100> Cathode chamber K K <102> and anode chamber K A <101> And, the intermediate room K M <103> And, it is equipped with.

[0022] Cathode chamber K K <102> is the cathode electrode E K <105> And, Entrance Z KK <107> And Exit A KK <109> And, it is equipped with. Anode chamber K A <101> is the anode electrode E A <104> And Exit A KA <106> and, equipped with connection V AM <112> Through the intermediate chamber K M <103> is connected to Intermediate room K M <103> is the entrance Z KM <108> Equipped with. The three-chamber tank is E <100> The exterior wall of <117> The cathode chamber is bounded by K <102> The NaSICON solid electrolyte F is also selectively permeable to sodium ions. K <111> By Intermediate Chamber K M <103> It is separated from the intermediate room K.M <103> Furthermore, the diffusion barrier D <110> Anode chamber K A <101> It is partitioned from NaSICON solid electrolyte F K <111> and diffusion barrier D <110> Three-chamber tank E <100> The diffusion barrier D extends throughout the entire depth and height of the <110> is made of glass.

[0023] In the embodiment according to FIG. AM <112> Electrolyzer E <100> The outer side of the connection V is in particular formed by a tube or hose, the material of which may be selected from rubber, metal and plastic. AM <112> Through the three-chamber tank E <100> Outer wall W A <117> Outside the intermediate chamber K M <103> From anode chamber K A <101> It is possible to send to the connection V AM <112> is the intermediate chamber K M <103> At the bottom of the electrolytic cell E <100> Outer wall W A <117> Exit A through KM <118> and anode chamber K A <101> At the bottom of the electrolytic cell E <100> Outer wall W A <117> Entrance Z through KA <119> It connects the two.

[0024] Sodium chloride solution at pH 10.5 L3 <114> But the entrance Z KM <108> through the middle chamber K in the direction of gravity. M <103> Introduced into the intermediate chamber K M <103> Exit A from KM <118> and anode chamber K A <101> Entrance to Z KA <119> The connection formed between V AM <112> is the intermediate chamber K M <103> Anode chamber K A <101> Connect to Sodium chloride solution L3 <114> This connection V AM <112> Through the intermediate chamber K M<103> From anode chamber K A <101> will be sent. Sodium methoxide in methanol L2 <113> is the entrance Z KK <107> via cathode chamber K K <102> will be sent.

[0025] At the same time, the cathode electrode E K <105> and anode electrode E A <104> A voltage is applied between the electrolyte L2 <113> The methanol in the cathode chamber K is reduced. K <102> Methoxide and H2 are generated (CH3OH+e - →CH3O - +1 / 2H2). At the same time, sodium ions enter the middle chamber K M <103> NaSICON Solid Electrolyte F K <111> Through the cathode chamber K K <102> Overall, this results in the cathode chamber K K <102> The concentration of sodium methoxide in the methanol solution L1 increases. <115> The sodium methoxide concentration is L2 <113> is rising compared to

[0026] Anode chamber K A <101> In the case of chlorine, oxidation of chloride ions occurs, producing chlorine molecules (Cl - →1 / 2Cl2+e - ). Exit A KA <106> So, aqueous solution L4 <116> The NaCl content of L3 <114> The amount of chlorine gas (Cl2) in water is reduced compared to that in the water. The reaction of Cl2+H2O→HOCl+HCl produces hypochlorous acid and hydrochloric acid, which then react with water molecules to produce acidic acid. The acidity is reduced by the NaSICON solid electrolyte. <111> However, the configuration according to the present invention can prevent damage to the anode chamber K A <101> Therefore, the electrolytic cell E <100> In NaSICON solid electrolyte F K <111> This will significantly extend its lifespan.

[0027] Intermediate room K M <103> Contains glass or plastic beads <121> Includes mesh wire basket <122> Internal structure of the form <120> There are also wire baskets. <122> is the intermediate chamber K M <103> Although it is placed independently within the <117> The entrance Z may be fixed to the inside of the outer wall. KM <108> Aqueous solution L3 supplied through <114> These internal structures <120> This turbulent flow in the solution L3 <114> is the intermediate chamber K where electrolysis is in progress. M <103> This prevents the development of a pH gradient within the NaSICON solid electrolyte. <111> This prevents the pH of the solution directly adjacent to the NaSICON solid electrolyte from decreasing. <111> The service life of the equipment will be further extended.

[0028] Figure 2 shows a further embodiment of an electrolytic cell according to the invention and a method according to the invention corresponding to the one shown in figure 1. One difference is that the intermediate chamber K M <103> From anode chamber K A <101> Connection to V AM <112> However, the diffusion barrier D <110> It is formed by perforating the internal structure. <120> As the intermediate chamber K M <103> Wire basket located loosely within <122> Instead, NaSICON solid electrolyte F K <111> Intermediate room K facing M <103> Alternatively or additionally, the diffusion barrier D <110> It is also possible to provide a corresponding stud <123-1> facing the inlet Z . KM <108> Aqueous solution L3 supplied through <114> These internal structures <120> Solution L3 is swirled by <114> This turbulence in the intermediate chamber K during electrolysis M <103> This destroys the pH gradient that develops within the

[0029] 4. Detailed Description of the Invention 4.1 Electrolyzer E The first aspect of the present invention is an electrolytic cell E <100> The electrolytic cell E in the first aspect of the present invention <100> At least one anode chamber K A <101> and at least one cathode chamber K K <102> and at least one intermediate chamber K M <103> and, A <101> and / or cathode chamber K K <102> and / or intermediate chamber K M <103> Electrolytic cell E having <100> Such electrolytic cells, whose chambers are interconnected in the form of modules, are described, for example, in DE-A 258143 and US-A 2006 / 0226022.

[0030] Anode chamber K A <101> is the anode electrode E A <104> This type of useful anode electrode E A <104> are all electrodes familiar to the skilled artisan that are stable under the conditions of the method according to the invention in the second aspect of the invention. These are in particular described in paragraph

[0024] of WO 2014 / 008410 or in paragraph

[0025] of DE 10360758 A1.

[0031] This electrode E A <104> may consist of a single layer or may consist of multiple parallel planar layers, each of which may be perforated or expanded. A <104> comprises a material selected from the group consisting of ruthenium oxide, iridium oxide, nickel, cobalt, nickel tungstate, nickel titanate, titanium or a noble metal (such as, in particular, platinum) supported on a support such as Kovar® (an iron / nickel / cobalt alloy whose individual components are preferably as follows: 54% by weight iron, 29% by weight nickel, 17% by weight cobalt). Further possible anode materials are, in particular, stainless steel, lead, graphite, tungsten carbide, titanium diboride. Preferably, the anode electrode EA <104> contains a titanium anode coated with ruthenium oxide / iridium oxide (RuO2+IrO2 / Ti).

[0031] Cathode chamber K K <102> is the cathode electrode E K <105> This type of useful cathode electrode E K <105> are all electrodes well known to the person skilled in the art that are stable under the conditions. They are described in particular in paragraph

[0025] of WO 2014 / 008410 or in paragraph

[0030] of DE 10360758 A1. This electrode E K <105> may be selected from the group consisting of mesh wool, three-dimensional matrix structures and "balls". K <105> In particular, E comprises a material selected from the group consisting of steel, nickel, copper, platinum, platinized metals, palladium, palladium on carbon, and titanium. K <105> contains nickel.

[0032] At least one intermediate chamber K M <103> But, anode chamber K A <101> and cathode chamber K K <102> It exists between.

[0033] Electrolytic cell E <100> is usually the outer wall W A <117> Exterior wall W A <117> is made of a material selected from the group consisting of steel, preferably rubberized steel, plastic, in particular Telene® (thermosetting polydicyclopentadiene), PVC (polyvinyl chloride), PVC-C (post-chlorinated polyvinyl chloride), PVDF (polyvinylidene fluoride). A <117> may be specially perforated for inlets and outlets. A <117> At least one anode chamber K A <101> and at least one cathode chamber K K <102> and at least one intermediate chamber K M <103> There is a saying.

[0034] K M <103> is the diffusion barrier D <110> By K A <101> From the above, the alkali metal cation conductive solid electrolyte F K <111> By K K <102> It is separated from

[0035] Diffusion Barrier D <110> For the anode chamber K, all materials can be used which are stable under the conditions of the method according to the second aspect of the invention. A <101> from the liquid present in the intermediate chamber K M <103> This can prevent or retard the transfer of protons to the

[0036] Diffusion barrier D used <110> is specifically a non-ion specific barrier or a membrane permeable to specific ions. <110> is preferably a non-ion specific barrier.

[0037] The material of the non-ion-specific partition is in particular selected from the group consisting of fabrics (in particular textile fabrics or metal fabrics), glasses (in particular sintered glass or glass frits), ceramics (in particular ceramic frits), membrane diaphragms, more preferably glass.

[0038] Diffusion Barrier D <110> When a membrane is "permeable to specific ions," it is meant in accordance with the present invention that the respective membrane promotes the diffusion of the specific ions in preference to other ions. More specifically, this means a membrane that promotes the diffusion of ions of a specific charge type in preference to ions of the opposite charge. Even more preferably, a membrane that is permeable to specific ions also promotes the diffusion of specific ions having a certain charge type in preference to other ions having the same charge type.

[0039] Diffusion Barrier D <110> is a "membrane permeable to certain ions", diffusion barrier D <110> is in particular an anion- or cation-conducting membrane.

[0040] According to the invention, anion-conducting membranes are membranes that selectively conduct anions, preferably membranes that selectively conduct certain anions, i.e. they promote the diffusion of anions over the diffusion of cations, in particular protons, and even more preferably they promote the diffusion of certain anions in preference to the diffusion of other anions.

[0041] According to the invention, cation-conducting membranes are membranes that selectively conduct cations, preferably membranes that selectively conduct certain cations, i.e. they promote the diffusion of cations over that of anions. Even more preferably, they further promote the diffusion of certain cations in preference to the diffusion of other cations. More preferably, they promote the diffusion of cations other than protons, more preferably the diffusion of sodium cations, in preference to protons.

[0042] "Promoting the diffusion of a specific ion X in preference to the diffusion of other ions Y" refers more specifically to the diffusion coefficient (unit: m) of ion type X in the membrane at a given temperature. 2 / sec) is 10 times, preferably 100 times, preferably 1,000 times higher than the diffusion coefficient of ion type Y in the membrane.

[0043] Diffusion Barrier D <110> is a "membrane permeable to certain ions", the anode chamber K A <101> From intermediate room K M <103> To prevent the diffusion of protons to the <110> is preferably an anion conductive membrane.

[0044] The anion-conducting membrane used is in particular a membrane selective for the anions contained in the salt S. Such membranes are known to and can be used by those skilled in the art.

[0045] The salt S is preferably a halide, sulfate, sulfite, nitrate, hydrogencarbonate or carbonate of X, more preferably a halide.

[0046] The halides are fluoride, chloride, bromide and iodide. The most preferred halide is chloride.

[0047] The anion-conducting membrane used is preferably a membrane selective for halides, preferably chloride.

[0048] Anion-conducting membranes are described, for example, in MA Hickner, AM Herring, EB Coughlin, Journal of Polymer Chemistry Part B: Polymer Physics 2013, 51, pp. 1727-1735, CG Arges, V. Ramani, PN Pintauro, Electrochemical Society Interface 2010, 19, pp. 31-35, WO 2007 / 048712, and Volkmar M. Schmidt, Textbook "Electrochemical Engineering: Fundamentals, Reaction Techniques, Process Optimization," First Edition (October 8, 2003), p. 181.

[0049] Even more preferably, the anion-conducting membrane used is an organic polymer selected in particular from polyethylene, polybenzimidazole, polyetherketone, polystyrene, polypropylene, and fluorinated membranes such as polyperfluoroethylene, preferably polystyrene. These are -NH3 + , -NRH2 + , -NR3 + , =NR + , -PR3 + wherein R is preferably an alkyl group having 1 to 20 carbon atoms, or other cationic group. They are selected from -NH3 + , -NRH2 + and -NR3 + More preferably, it is selected from -NH3 + and -NR3 +and more preferably -NR3 + It is preferred that the aryl group has a covalently attached functional group which is

[0050] Diffusion Barrier D <110> If is a cation-conducting membrane, it is a membrane that is selective in particular for the cations contained in the salt S. Even more preferably, the diffusion barrier D <110> is an alkali metal cation conducting membrane, more preferably a potassium and / or sodium ion conducting membrane, and most preferably a sodium ion conducting membrane.

[0051] Cation-conducting membranes are described, for example, on page 181 of Volkmar M. Schmidt's textbook "Electrochemical Engineering: Fundamentals, Reaction Techniques, Process Optimization," first edition (October 8, 2003).

[0052] Even more preferably, the cation-conducting membrane used is an organic polymer selected in particular from fluorinated membranes such as polyethylene, polybenzimidazole, polyetherketone, polystyrene, polypropylene, and polyperfluoroethylene, preferably polystyrene and polyperfluoroethylene. - , -COO - , -PO3 2- and -POH - , preferably -SO3 - (described in German Patent Application No. 10 2010062804, U.S. Pat. No. 4,831,146).

[0053] This can be, for example, sulfonated polyperfluoroethylene (Nafion®, CAS number: 31175-20-9). These are known to the skilled artisan, for example, from WO 2008 / 076327, paragraph

[0058] , US 2010 / 0044242, paragraph

[0042] , or US 2016 / 0204459, and are commercially available under the trade names Nafion®, Aciplex® F, Flemion®, Neosepta®, Ultrex®, PC-SK®. Neosepta® membranes are described, for example, in SAMareev, D.Yu.Butylskii, NDPismenskaya, C.Larchet, L.Dammak, VVNikonenko, Journal of Membrane Science 2018, 563, pp. 768-776.

[0054] Cation-conducting membrane acts as a diffusion barrier D <110> When used as a polymer functionalized with sulfonic acid groups, this is, for example, a polymer functionalized with sulfonic acid groups, in particular a polymer functionalized with NAFION wherein n and m are independently 1 to 10. 6 an integer between 10 and 10 5 An integer up to 10 is more preferable. 2 From 10 4 is an integer up to

[0055] [ka]

[0056] Useful alkali metal cation conducting solid electrolytes F K <111> is introduced into the intermediate chamber K M <103> From cathode chamber K K<102> These solid electrolytes are all solid electrolytes that can be transported to a desired temperature range. Such solid electrolytes are known to the person skilled in the art and are described, for example, in DE 102015013155 A1, WO 2012 / 048032 A1, paragraphs

[0035] ,

[0039] ,

[0040] , US 2010 / 0044242 A1, paragraphs

[0040] ,

[0041] , and DE 10360758 A1, paragraphs

[0014] to

[0025] . They are commercially available under the names NaSICON, LiSICON, KSICON. Sodium ion conducting solid electrolytes F K <111> is preferred, and more preferably has a NaSICON structure. The NaSICON structure that can be used according to the present invention is also described, for example, in N. Anantharamulu, K. Koteswara Rao, G. Rambabu, B. Vijaya Kumar, Velchuri Radha, M. Vithal, J Mater Sci 2011, 46, pp. 2821-2837.

[0057] NaSICON preferably has the structure: M I 1+2w+x-y+z M II w M III x Zr IV 2-w-x-y M V y (SiO4) z (PO4) 3-z

[0058] In the formula, M I is Na + , Li + Preferably, Na + It is. M II is a divalent metal cation, preferably Mg 2+ , Ca 2+ , Sr 2+ , B.A. 2+ , Co 2+ , Ni 2+ More preferably, Co 2+, Ni 2+ is selected from. M III is a trivalent metal cation, preferably Al 3+ , Ga 3+ , Sc 3+ , La 3+ , Y 3+ , Gd 3+ , Sm 3+ , Lu 3+ , Fe 3+ , Cr 3+ More preferably, Sc 3+ , La 3+ , Y 3+ , Gd 3+ , Sm 3+ Particularly preferably, Sc 3+ , Y 3+ , La 3+ is selected from. M V is a pentavalent metal cation, preferably V 5+ , Nb 5+ , Ta 5+ is selected from.

[0059] The Roman numerals I, II, III, IV, and V indicate the oxidation states of the respective metal cations.

[0060] w, x, y, z are real numbers with 0≦x<2, 0≦y<2, 0≦w<2, 0≦z<3, and w, x, y, z are selected such that 1+2w+x-y+z≧0 and 2-wxy≧0.

[0061] Even more preferably according to the invention, NaSICON has the formula Na (1+v) Zr2Si v P (3-v) O 12 wherein v is a real number, 0≦v≦3. Most preferably, v=2.4.

[0062] Cathode chamber K K <102> can also be used in liquids, e.g. solution L2 <113> Cathode chamber K K<102> and the liquid present therein, e.g. solution L1 <115> and the inlet Z, which allows for the removal of KK <107> and Exit A KK <109> Equipped with Entrance Z KK <107> and Exit A KK <109> The solution is in the cathode chamber K K <102> When the current flows through the cathode electrode E K <105> In contact with the cathode chamber K K <102> This is a solution of alkali metal alkoxide XOR in alcohol ROH L2 <113> K K <102> In the second aspect of the present invention, the method according to the present invention is carried out to KK <109> Solution L1 <115> This is a necessary condition to obtain

[0063] Anode chamber K A <101> Also, the anode chamber K A <101> The liquid present in the <106> Exit A allows removal of KA <106> Further, the intermediate chamber K M <103> is the entrance Z KM <108> Furthermore, K A <101> and K. M <103> is the liquid K M <103> From K A <101> Connections that can be sent to V AM <112> As a result, the solution L3 <114> is the entrance Z KM <108> via K M <103> This was introduced in K M <103> Then it passes through V AM <112> via anode chamber K A <101> and finally to the anode chamber K A <101> Pass through. V AM <112> and Exit A KA <106> Solution L3 <114> Anode chamber K A <101> When the water flows through the anode electrode E A <104> In contact with the anode chamber KA <101> This is the solution L3 <114> First K M <103, then V AM <112> , then K A <101> When passing through outlet A, the method according to the invention is carried out in a second embodiment. KA <106> In aqueous solution L4 <116> This is a necessary condition to obtain

[0064] Entrance Z KK <107> , Z KM <108> , Z KA <119> and Exit A KK <109> , A KA <106> , A KM <118> is electrolytic cell E by methods known to those skilled in the art. <100> It can be attached to.

[0065] Connection V AM <112> Electrolyzer E <100> In and / or electrolytic cell E <100> Outside the electrolytic cell E <100> It may be formed within.

[0066] Connection V AM <112> Electrolytic cell E <100> If formed within the connection V AM <112> is the diffusion barrier D <110> It is preferred that the groove is formed by at least one perforation.

[0067] Connection V AM <112> Electrolytic cell E <100> If it is formed outside the electrolytic cell E <100> K extending outside M <103> and K. A <101> It is preferable that the connecting portion is formed by connecting the In particular, the exterior wall W A <117> Exit A through KM <118> is the intermediate chamber K M <103> Preferably, the intermediate chamber K M <103> At the bottom of the inlet Z KM <108> is the intermediate chamber K M <103> It is more preferable that the outer wall W is located at the upper end of the outer wall W.A <117> Entrance Z through KA <119> Anode chamber K A <101> Among them, preferably the anode chamber K A <101> These are connected by a conduit, such as a pipe or hose, preferably comprising a material selected from rubber and plastic. And outlet A KA <106> Anode chamber K A <101> It is more preferable that the ion exchange layer 11 is located at the upper end of the ion exchange layer 11 .

[0068] "Intermediate room K M <103> Exit A at the bottom of KM <118> " refers to solution L3 <114> In the direction of gravity, the middle chamber K M <103> Exit A KM <118> Electrolytic cell E <100> This means that the device is attached to the

[0069] "Anode chamber K A <101> Inlet Z at the bottom of KA <119> " refers to solution L3 <114> Against gravity, the anode chamber K A <101> To enter, enter the entrance Z KA <119> Electrolytic cell E <100> This means that the device is attached to the

[0070] "Intermediate room K M <103> Entrance Z at the top of KM <108> " refers to solution L3 <114> In the direction of gravity, the middle chamber K M <103> To enter, enter the entrance Z KM <108> Electrolytic cell E <100> This means that the device is attached to the

[0071] "Anode chamber K A <101> Exit A at the top of KA <106> " refers to solution L4 <116> Against gravity, the anode chamber K A <101> Exit A KA <106> Electrolytic cell E <100> This means that the device is attached to the

[0072] In this embodiment, exit A KM <118> The outer wall W A <117> By the intermediate chamber K M <103> At the bottom of the inlet Z KA <119> The outer wall W A <117> Anode chamber K A <101> This is particularly advantageous and therefore preferred when the anode chamber K A The gas generated in the L4 <116> In order to separate them further, the anode chamber K A <101> It is possible to remove it from

[0073] In particular, connection V AM <112> Electrolytic cell E <100> When the conductor is formed outside the conductor, as shown in FIG. KM <108> and A KM <118> is the intermediate chamber K M <103> Outer wall W A <117> (i.e., electrolytic cell E <100> Z at the bottom KM <108> , electrolytic cell E <100> A at the top KM <118> , or vice versa.) and Z KA <119> and A KA <106> Anode chamber K A <101> Outer wall W A <117> (i.e., electrolytic cell E <100> Z at the bottom KA <119> , electrolytic cell E <100> A at the top KA <106> , or vice versa.) This arrangement allows L3 <114> There are two rooms, M <103> and K. A <101> Z KA <119> and Z KM <108> Electrolyzer E <100> It is possible to form the same side of A KM <118> and A KA <106> Electrolyzer E automatically <100> Alternatively, as shown in Figure 1, KA<119> and Z KM <108> Electrolyzer E <100> It is also possible to form it on both sides of A. KM <118> and A KA <106> Electrolyzer E automatically <100> is formed on both sides of the

[0074] Connection V AM <112> Electrolytic cell E <100> This is especially true when the electrolytic cell E <100> The upper end or bottom of the electrolytic cell E, preferably the upper end as shown in FIG. <100> On the A side, there is an inlet Z KM <108> and Exit A KA <106> There is a diffusion barrier D <110> From this side ("side A"), electrolytic cell E <100> The electrolytic cell E <100> The opposite side ("side B") of the electrolytic cell E is not completely reached. <100> At the same time, the diffusion barrier D <110> Three-chamber tank E <100> 50% or more of the height of the three-chamber tank E <100> 60% to 99% of the height of the three-chamber tank E <100> 70% to 95% of the height of the three-chamber tank E <100> 80% to 90% of the height of the three-chamber tank E <100> The diffusion barrier D <110> The three-room rowing <100> Since it does not contact the B side of the diffusion barrier D <110> and Three-chamber Tank E <100> B side exterior wall W A <117> In this case, a gap will occur between the connection V AM <112> This shape allows L3 <114> There are two rooms, M <103> and K. A <101> Be sure to pass through.

[0075] According to these embodiments, the aqueous salt solution L3 <114> But the anode electrode E A <104> It most likely flows through an acid-sensitive solid electrolyte before coming into contact with the electrolyte, resulting in the formation of an acid.

[0076] According to the present invention, "electrolytic cell E <100> The bottom of the electrolytic cell E is the bottom of the solution (e.g., A in FIG. 1). KM <118> In the case of L3 <114> ) flows out of the electrolytic cell E in the same direction as gravity, or in the electrolytic cell E, the solution (e.g., Z in Figs. 1 and 2) KK <107> In the case of L2 <113> , and A in Fig. 1 KA <119> In the case of L3 <114> ) is the side that is fed to electrolytic cell E against the force of gravity.

[0077] According to the present invention, the "upper end of the electrolytic cell E" refers to the upper end of the electrolytic cell E where the solution (e.g., A KA <106> In the case of L4 <116> , and A KK <109> In the case of L1 <115> ) flows out of the electrolytic cell E against gravity, or in the electrolytic cell E, the solution (e.g., Z KM <108> In the case of L3 <114> ) is the side that is supplied to electrolytic cell E in the same direction as gravity.

[0078] According to the invention, the intermediate chamber K M is the internal structure <120> According to the present invention, the internal structure <120> is a solid material. Suitable internals of this type are any article or structure known to those skilled in the art that is sufficiently inert to the electrolysis conditions.

[0079] internal structure <120> It especially comprises at least one material selected from rubber, plastic, in particular those selected from polystyrene, polypropylene, PVC, PVC-C, glass, porcelain, metal, which is a metal or an alloy of two or more metals selected from titanium, iron, molybdenum, chromium, nickel, preferably an alloy comprising at least two metals selected from titanium, iron, molybdenum, chromium, nickel, even more preferably a steel alloy comprising besides iron at least one further metal selected from titanium, molybdenum, chromium, nickel, most preferably a stainless steel.

[0080] internal structure <120> are in particular selected from structured packings, non-structured packings (random packings) and trays, such as bubble cap trays, valve trays, tunnel cap trays, Thoman trays, cross-slot bubble cap trays or sieve trays.

[0081] Non-structured packings are generally random packings. The random packings used are usually Raschig rings, Pall rings, Berl saddles or Intalox® saddles. Structured packings are, for example, sold under the name Mellapak® by the company Sulzer.

[0082] internal structure <120> As shown in Figure 1, the intermediate chamber K M <103> It may be free in the container, for example a sphere made of glass, etc. <121> But the wire structure <122> The basket may be comprised of:

[0083] Or internal structure <120> Also, for example, the solid electrolyte F K <111> , diffusion barrier D <110> , or intermediate chamber K M <103> The outer wall that bounds the interior of <117> The fixing can be carried out by methods known to those skilled in the art, for example by screw connections, clamps, gluing (polymer glue, PVC glue).

[0084] Therefore, the stud <123-2> shown in Figure 2 is a solid electrolyte F K <111> The stud <123-1> is attached to the diffusion barrier D <110> The corresponding studs are attached to the intermediate chamber K. M <103> The outer wall that bounds the interior of <117> , in which case a stalactite or stalagmite-like structure is formed within the intermediate chamber.

[0085] Alkali metal cation conducting solid electrolyte F K<111> or diffusion barrier D <110> Internal structure of <120> The fixation can be achieved, for example, by fixing the internal structure to the wire framework of the wall.

[0086] Electrolytic cell E according to the first aspect of the invention <100> In a preferred embodiment of the present invention, the internal structure <120> is the intermediate chamber K M The proportion ζ of the inner volume is 1% to 99%, more preferably 10% to 99%, even more preferably 40% to 90%, even more preferably 50% to 90%, even more preferably 60% to 90%, and most preferably 80% to 90%.

[0087] The percentage ζ (unit: %) is ζ = [(V O -V M ) / V O ]*100.

[0088] V O is the intermediate chamber K M <103> is the internal structure <120> When the intermediate chamber K is not provided M <103> A liquid that can be contained in the electrolyte L3 <114> is the maximum volume. V M is the intermediate chamber K M <103> is the internal structure <120> When equipped with an intermediate chamber K M <103> A liquid that can be contained in the electrolyte L3 <114> is the maximum volume.

[0089] Surprisingly, the intermediate room K M <103> Internal structure <120> In the method according to the invention, the intermediate chamber K M <103> Electrolyte L3 passing through <114> It has been found that this induces turbulence and vortexes in the electrolyte, which slows down or completely prevents the formation of a pH gradient during electrolysis, thereby reducing the pH sensitivity of the acid-sensitive solid electrolyte F. K <111> is protected and therefore electrolysis run times and cell life can be extended.

[0090] internal structure <120> is the intermediate chamber K M <103> and anode chamber K A <101> Electrolyte L3 passing through <114> In order to fully allow or not completely block the flow of M <103> It will be clear that it can be attached to

[0091] In a preferred embodiment of the electrolytic cell according to the invention, the internal structure <120> is the entrance Z KM <108> and connected V AM <112> And the middle room K M Block direct connections in.

[0092] Intermediate room K M At the entrance Z KM <108> and connection V AM <112> Whether the direct route between them is blocked is confirmed by the following "thread test." 1.Entrance Z KM <108> From intermediate room K M Pass the thread through the opening leading to the connection V AM <112> From intermediate room K M The thread is pulled out from an opening leading to the intermediate chamber K. M long enough to extend beyond the 2. Apply opposite forces to both ends of the thread so that it is taut without breaking. 3. When the yarn is placed in the intermediate chamber and stretched taut according to steps 1 and 2, if there is at least one yarn that contacts the internal structure, the intermediate chamber K M At the entrance Z KM <108> and connection V AM <112> The requirement to block the direct route between the two countries has been met. 4. When the yarn is placed in the intermediate chamber and stretched taut according to steps 1 and 2, if no yarn comes into contact with the internal structure, the intermediate chamber K M At the entrance Z KM <108> and connection V AM <112> The requirement to block a direct route between the two countries has not been met.

[0093] The threads are made in particular from sewing thread (eg Gutermann), fishing line and string. Most preferably, a 0.2 mm diameter fishing line, such as that available from Hemingway or Nexos, is used for the thread test.

[0094] 4.2 The method according to the invention The method according to the second aspect of the invention comprises an electrolytic cell E according to the first aspect of the invention <100> In the alkali metal alkoxide XOR alcohol ROH solution L1 <115> This is a method for generating

[0095] The method according to the second aspect of the invention comprises steps (a), (b) and (c) which proceed simultaneously.

[0096] In step (a), a solution L2 containing alcohol ROH <113> , preferably a solution L2 containing an alkali metal alkoxide XOR and an alcohol ROH <113> is K K <102> X is an alkali metal cation and R is an alkyl group having 1 to 4 carbon atoms.

[0097] X is preferably Li + , K + , Na + More preferably, K + , Na + Most preferably, X=Na + It is.

[0098] R is preferably selected from the group consisting of n-propyl, iso-propyl, ethyl and methyl, more preferably selected from the group consisting of ethyl and methyl. R is most preferably methyl.

[0099] Solution L2 <113> According to the present invention, "water-free" means that the solution L2 <113> of alcohol ROH in solution L2 <113> This means that the weight (mass ratio) of water in the aqueous solution is 1:10 or less, more preferably 1:20 or less, even more preferably 1:100 or less, and even more preferably 0.5:100 or less.

[0100] Solution L2 <113> If contains XOR, solution L2 <113> Solution L2 for the whole <113> The mass proportion of XOR therein is in particular from 0% to more than 30% by weight, preferably from 5% to 20% by weight, more preferably from 10% to 20% by weight, more preferably from 10% to 15% by weight, most preferably from 13% to 14% by weight and very most preferably 13% by weight.

[0101] Solution L2 <113> If contains XOR, solution L2 <113> The mass ratio of XOR to the alcohol ROH therein is in particular in the range of 1:100 to 1:5, more preferably in the range of 1:25 to 3:20, even more preferably in the range of 1:12 to 1:8, and even more preferably 1:10.

[0102] In step (b), a neutral or alkaline aqueous solution L3 of a salt S containing X as a cation <114> is K M <103> Then through V AM <112> Via K A <101> Pass through.

[0103] The salt S is preferably a halide, sulfate, sulfite, nitrate, hydrogencarbonate or carbonate of X, more preferably a halide.

[0104] The halides are fluoride, chloride, bromide and iodide. The most preferred halide is chloride.

[0105] Aqueous solution L3 <114> The pH is 7.0 or higher, preferably in the range of 7 to 12, more preferably in the range of 8 to 11, even more preferably in the range of 10 to 11, and most preferably 10.5.

[0106] Solution L3 <113> The mass fraction of salt S in solution L3 <113> The content is preferably in the range of 0% by weight to over 20% by weight, preferably 1% by weight to 20% by weight, more preferably 5% by weight to 20% by weight, even more preferably 10% by weight to 20% by weight, and most preferably 20% by weight, based on the total.

[0107] Surprisingly, in step (b), the intermediate chamber K M <103> Internal structure <120> In the method according to the invention, the intermediate chamber K M <103> Electrolyte L3 flows through <114> It has been found that turbulence and vortexes occur in the electrolyte, which slows down or completely prevents the formation of a pH gradient during electrolysis, thereby reducing the pH gradient in the acid-sensitive solid electrolyte F. K <111> is protected and therefore electrolysis run times and cell life can be extended.

[0108] Then, in step (c), E A <104> and E K <105> A voltage is applied between the

[0109] This causes current to move from the charging source to the anode, transfer charge through the ions to the cathode, and finally return the current to the charging source. Charging sources are known to those skilled in the art and are typically rectifiers that can convert AC to DC and generate a specific voltage through a transformer.

[0110] This results in the following: L1 <115> The XOR concentration in L2 <113> When the XOR concentration in solution L1 is higher than that in solution L2, <115> Exit A KK <109> is obtained. L4 <116> The S concentration in the <114> The concentration of S in the aqueous solution L4 is lower than that in the <116> Exit A KA <106> is obtained.

[0111] In particular, in the method according to the second aspect of the invention, the current density (= intermediate chamber K M <103> The ratio of the current supplied to the electrolytic cell to the area of ​​the solid electrolyte in contact with the anolyte present in the cell is 10 to 8000 A / m 2 More preferably, it is in the range of 100 to 2000 A / m 2 , and more preferably 300 to 800 A / m 2 , more preferably 494 A / m 2 A voltage is applied so as to pass a current of K, which can be measured by one skilled in the art using standard methods. M <103> The area of ​​the solid electrolyte in contact with the anolyte present in the electrolyte is preferably in the range of 0.00001 to 10 m 2 , preferably 0.0001 to 2.5 m 2 , more preferably 0.0002 to 0.15 m 2 , and even more preferably 2.83 cm 2 It is.

[0112] Step (c) of the method according to the second aspect of the invention comprises two chambers K M <103> and K. A <101> At least partially L3 <114> Filled with K K <102> At least partially in L2 <113> It will be clear that this is carried out when the

[0113] In step (c), A <104> and E K <105> The fact that charge transfer occurs between L2 to the extent that the circuit is protected <113> or L3 <114> is electrode E A <104> and E K <105> Covering the K K <102> , K M <103> , and K A <101> At the same time, L2 <113> or L3 <114> This means that it is filled with

[0114] This is especially true for L3 <114> A liquid stream of K M <103> , VAM <112> and K. A <101> Continuously passing through L2 <113> A liquid stream of K K <102> Through L3 <114> The liquid stream at electrode E A <104> Covering L2 <113> The liquid stream at electrode E K <105> This is the case when the coating at least partially, preferably completely, covers the

[0115] Electrolyte L3 <114> The stream of K M <103> Because the interior of the chamber is in contact with the internal structure, a typical pH gradient does not form within the chamber. <120> But, the middle room K M At the entrance Z KM <108> and connected V AM <112> This is even more pronounced when the direct connection between these internal structures is cut off. <120> But, the middle room K M <103> Electrolyte L3 passing through <114> This is because it is located in the flow path of the river and interrupts the continuous flow.

[0116] This desired effect can be achieved in the method according to the second aspect of the invention by the intermediate chamber K M <103> Electrolyte L3 passing through <114> is preferably increased by varying the flow rate of the pH gradient, which can create additional turbulence that counteracts the formation of a pH gradient.

[0117] In a further preferred embodiment, the method according to the second aspect of the invention is carried out continuously, i.e. steps (a) and (b) are carried out continuously whilst applying a voltage as in step (c).

[0118] After carrying out step (c), L1 <115> The XOR concentration in L2 <113> When the XOR concentration in solution L1 is higher than that in solution L2, <115> Exit A KK<109> It is obtained by L2 <113> If already contains XOR, L1 <115> The XOR concentration in L2 <113> is preferably 1.01 to 2.2 times, more preferably 1.04 to 1.8 times, even more preferably 1.077 to 1.4 times, still more preferably 1.077 to 1.08 times, and most preferably 1.077 times higher than the XOR concentration in L1 <115> and L2 <113> The mass proportion of XOR therein is more preferably in the range of 10% by weight to 20% by weight, and even more preferably in the range of 13% by weight to 14% by weight.

[0119] L4 <116> The S concentration in the <114> The concentration of S in the aqueous solution L4 is lower than that in the <116> Exit A KA <106> is obtained.

[0120] Aqueous solution L3 <114> The concentration of the cation X in the aqueous solution L4 is preferably in the range of 3.5 to 5 mol / L, more preferably 4 mol / L. <116> The concentration of the cation X in the aqueous solution L3 used in each case is <114> It is more preferable that the concentration is 0.5 mol / L lower than the concentration of

[0121] In particular, the process according to the second aspect of the present invention is carried out at a temperature between 20°C and 70°C, preferably between 35°C and 65°C, more preferably between 35°C and 60°C, even more preferably between 35°C and 50°C, and at a pressure between 0.5 bar and 1.5 bar, preferably between 0.9 bar and 1.1 bar, more preferably at 1.0 bar.

[0122] In the course of carrying out the method according to the invention, hydrogen is typically introduced into the cathode chamber K K <102> This is generated in Exit A KK <109> Solution L1 via <115> Then, in certain embodiments of the present invention, hydrogen and solution L1 <115> The mixture of chlorine and other halogen gases can be separated by methods known to those skilled in the art. If the alkali metal compound used is a halide, in particular a chloride, then chlorine or other halogen gases are separated from the anode chamber K A <101> This may be generated at exit A KK<106> Solution L4 via <116> In addition, oxygen and / or carbon dioxide may be produced and may be removed as well. In certain embodiments of the invention, chlorine, oxygen and / or CO2 may then be mixed with solution L4 <116> The mixture of chlorine, oxygen and / or CO2 gases can then be separated by methods known to those skilled in the art. <116> It is likewise possible to separate them after separation from the hydroxyl group by methods known to those skilled in the art.

[0123] These results are surprising and unexpected in the light of the prior art. The method according to the invention does not require the sacrifice of alkoxide solution from the cathode compartment as a buffer, as in the prior art, and protects the acid-labile solid electrolyte from corrosion. The method according to the invention is therefore more efficient than the method described in WO 2008 / 076327, which uses product solution in the intermediate compartment, reducing the overall conversion. Furthermore, the acid-labile solid electrolyte is less likely to be corroded by the internal structure. <120> prevents the formation of a pH gradient and thus stabilizes it. EXAMPLES

[0124] Comparative Example 1 Sodium methoxide (SM) was produced by a cathodic process in which a 20 wt% aqueous solution of NaCl was fed to the anode chamber and a 10 wt% methanolic SM solution was fed to the cathode chamber. This electrolytic cell is unique in that it has no internal structure in the intermediate chamber, i.e., it does not use glass beads as shown in Figure 1. <121> Wire basket with <122> The electrolytic cell consisted of three chambers corresponding to those shown in Figure 1, except that the anode chamber was not included. The connections between the intermediate chamber and the anode chamber were made by hoses attached to the bottom of the electrolytic cell. The anode chamber and the intermediate chamber were separated by 2.83 cm 2 The cathode and intermediate chambers were separated by an anion exchange membrane AMX (Tokuyama Corporation, ammonium groups on polymer). The cathode and intermediate chambers had an area of ​​2.83 cm. 2 The ceramic was of the NaSICON type, which has the formula Na 3.4 Zr 2.0 S 2.4 P 0.6 O12 The chemical composition was: The anolyte was transferred to the anode chamber via the intermediate chamber. The anolyte flow rate was 1 L / h and the catholyte flow rate was 90 mL / h, and a current of 0.14 A was applied. The temperature was 35 °C. The electrolysis was carried out at a constant voltage of 5 V for 500 h. Over time, a pH gradient was observed to develop in the intermediate chamber. This is due to the migration of ions to the electrodes during the electrolysis and the diffusion of protons produced in the further reaction at the anode. This local increase in pH is undesirable, as it attacks the solid electrolyte and may cause its corrosion or destruction, especially if the operation period is very long.

[0125] Comparative Example 2 Comparative Example 1 was reproduced using a two-chamber cell with only one anode and one cathode compartment, the latter separated from the cathode compartment by a NaSICON type ceramic. This cell therefore had no intermediate compartment. This is manifested in the fact that the ceramic corrodes even faster compared to Comparative Example 1, which results in a rapid rise in the voltage curve. If the initial voltage value is less than 5 V, it rises to more than 20 V within 100 hours.

[0126] Example 1 Glass beads <121> a wire framework having a basket disposed in the intermediate chamber; <122> Comparative Example 1 was reproduced using a basket. The basket occupied half of the middle chamber facing the NASICON solid electrolyte. This arrangement prevents the uniform flow of the electrolyte through the middle chamber and creates turbulence in the electrolyte, which makes it difficult for a pH gradient to form during electrolysis.

[0127] Example 2 Intermediate room K M <103> Comparative Example 1 was reproduced using cone-shaped structures <123-1> and <123-2> fixed to a NASICON ceramic or diffusion barrier in a ceramic housing. This arrangement also prevents uniform flow of the electrolyte through the intermediate chamber and causes turbulence, which makes it difficult for a pH gradient to form during electrolysis.

[0128] result The use of the three-compartment cell according to the invention in the method according to the invention prevents the corrosion of the solid electrolyte. At the same time, there is no need to sacrifice the alkali metal alkoxide product for the intermediate chamber, and the voltage remains constant. These advantages, which are evident from the comparison of the two comparative examples 1 and 2, highlight the surprising effectiveness of the invention.

[0129] Furthermore, the eddy currents and turbulences in the electrolyte in the intermediate chamber can reduce or destroy the pH gradient that builds up with the ongoing electrolysis, thus extending the life of the electrolysis chamber. This gradient can make electrolysis more difficult, cause corrosion, and ultimately cause the destruction of the solid electrolyte, especially during very long periods of operation. In the implementation of the present invention according to Examples 1 and 2, this pH gradient is destroyed, thereby further increasing the stability of the solid electrolyte, in addition to the above-mentioned advantages of a three-compartment cell over a two-compartment cell.

Claims

1. at least one anode chamber K Ａ <101>, and at least one cathode chamber K Ｋ <102>, and at least one intervening intermediate chamber K Ｍ <103>, and an electrolytic cell E<100> comprising the same, said K Ａ <101> is an anode electrode E Ａ <104>, and an outlet A ＫＡ <106>, and comprising the same, said K Ｋ <102> is a cathode electrode E Ｋ <105>, and an inlet Z ＫＫ <107>, and an outlet A ＫＫ <109>, and comprising the same, said K Ｍ <103> is an inlet Z ＫＭ <108>, and separated from K Ａ <101> by a diffusion barrier D<110>, and an alkali metal cation-conductive solid electrolyte F Ｋ <111> separates K Ｋ <102> therefrom, said K Ｍ <103> and K Ａ <101> are connected to each other by a connection V Ｍ <112> capable of sending liquid from K Ａ <103> to K ＡＭ <112>, said intermediate chamber K Ｍ <103> comprises an internal structure<120>, and said internal structure<120> is an electrolyte L Ｍ passing through said intermediate chamber K ３ <114> configured to introduce turbulent flow and vortices, electrolytic cell E<100>.

2. said alkali metal cation-conductive solid electrolyte FK<111> is of the formula M Ｉ １＋２ｗ＋ｘ－ｙ＋ｚ M ＩＩ ｗ M ＩＩＩ ｘ Zr ＩＶ ２－ｗ－ｘ－ｙ M Ｖ ｙ (SiO ４ ) ｚ (PO ４ ) ３－ｚ (wherein, M Ｉ is selected from Na ＋ and Li ＋ ; M ＩＩ is a divalent metal cation; M ＩＩＩ is a trivalent metal cation; M Ｖ is a pentavalent metal cation; The Roman numeral exponents I, II, III, IV, V indicate the oxidation number in which each metal cation exists; w, x, y, z are real numbers, where 0 ≤ x < 2, 0 ≤ y < 2, 0 ≤ w < 2, 0 ≤ z < 3; w, x, y, z are selected such that 1 + 2w + x - y + z ≥ 0 and 2 - w - x - y ≥ 0.) The electrolytic cell E<100> according to claim 1, having the structure of

3. The internal structure <120> is selected from the group consisting of trays, structured packings, and unstructured packings. The electrolytic cell E<100> according to claim 1.

4. The internal structure <120> contains at least one material selected from rubber, plastic, glass, porcelain, and metal. The electrolytic cell E<100> according to claim 1.

5. The connection V ＡＭ <112> is formed inside the electrolytic cell E<100>. The electrolytic cell E<100> according to claim 1.

6. The internal structure <120> occupies a ratio ζ of 1% to 99% of the volume inside the intermediate chamber K Ｍ ; ζ = [(V Ｏ - V Ｍ ) / V Ｏ * 100 (wherein, V Ｏ is the intermediate chamber K Ｍ When <103> does not include the internal structure <120>, the intermediate chamber K Ｍ is the maximum liquid volume that can be accommodated in <103>, V Ｍ is the intermediate chamber K Ｍ When <103> includes the internal structure <120>, the intermediate chamber K Ｍ is the maximum liquid volume that can be accommodated in <103>. ) The electrolytic cell E<100> according to claim 1, wherein is

7. The internal structure <120> blocks a direct path within the intermediate chamber K ＫＭ between the inlet Z<108> and the connection V<112> ＡＭ according to the thread test described in the specification. Ｍ The electrolytic cell E<100> according to claim 1.

8. A method for generating an alcohol ROH solution L<115> of an alkali metal alkoxide XOR in the electrolytic cell E<100> according to claim 1, １ comprising the following simultaneous steps: (a) A step of passing a solution L<113> containing the alcohol ROH through the K<102>, ２ Ｋ (b) A step of passing a neutral or alkaline aqueous solution L<114> of a salt S containing X as a cation through the K<103>, and then through the V<112> to the K<101>, ３ Ｍ ＡＭ Ａ (c) A step of applying a voltage between the E<104> and the E<105>, Ａ Ｋ whereby a solution L<115> having a higher concentration of XOR than the L<113> is supplied to the outlet A<109>, ＫＫ ２ １ the outlet A<109>, ＫＡ ​​​​​​​​​​​​​​To <106>, the L ３ An aqueous solution L of S having a lower concentration of S than <114> ４ is supplied to <116>, wherein X is an alkali metal cation and R is an alkyl group having 1 to 4 carbon atoms. **Claim 9** X is Li ＋ , Na ＋ , K ＋ The method according to claim 8, selected from the group consisting of **Claim 10** S is a halide, sulfate, sulfite, nitrate, bicarbonate or carbonate of X. The method according to claim 8. **Claim 11** R is selected from the group consisting of methyl and ethyl. The method according to claim 8. **Claim 12** The L ２ <113> contains the alcohol ROH and the alkali metal alkoxide XOR. The method according to claim 8. **Claim 13** The mass ratio of XOR to the alcohol ROH in the L ２ <113> is in the range of 1:100 to 1:

5. The method according to claim 12. **Claim 14** The XOR concentration in the L １ <115> is 1.01 to 2.2 times higher than the XOR concentration in the L ２ <113>. The method according to claim 12 or claim 13. **Claim 15** It is carried out at a temperature of 20 to 70 ° C and a pressure of 0.5 to 1.5 bar. The method according to claim 8. **Claim 16** The flow rate of the electrolyte L Ｍ passing through the intermediate chamber K ３ <114> varies during the implementation of step (b). The method according to claim 8.

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