EP4134472A1 - Method for producing alkaline metal alcaholates in an electrolysis cell - Google Patents

Abstract

The present invention relates to a method for producing an alkali metal alcoholate solution L₁ in an electrolytic cell E. The electrolytic cell E comprises at least one cathode chamber K_K and at least one anode chamber K<sub>A< /sub> and optionally a middle chamber K_M in between. The interior I_KK of the cathode chamber K_K is separated from the interior I_{by a partition W comprising at least one cation-conducting solid electrolyte ceramic F_A, for example NaSlCON >KA} of the anode chamber K_A or, in cases where the electrolytic cell E includes a central chamber K_M, from the interior I<sub>KM</ sub> of the middle chamber K_M separated. If the electrolytic cell E comprises a central chamber K_M, the inner space I_KM of the central chamber K_M is protected by a diffusion barrier D, for example one for cations or anion-selective membrane or a non-ion-specific dividing wall, from the interior I_KA of the anode chamber K_A. The interior I_KA of the anode chamber K_>A delimiting part O_EA of the upper side O_E is essentially designed as a plane, whose normal N_OEA has an angle 0 ° < ϕ_EA < 45° to the gravity vector V_s. In addition, the outlet A_KA is then arranged on the upper half of O_EA. Alternatively or additionally, preferably additionally, the interior is I_KK part O_EK of the upper side O_E delimiting the cathode chamber K_K essentially as a plane, the normal of which is N_OEK forms an angle 0° < ϕ_EK < 45° to the gravity vector V_s, and the flow A_KK is then on the upper half of O _EK arranged. This arrangement of the respective upper sides and drains means that the formation of gas cushions in the anode chamber is prevented. These gas cushions are undesirable because they reduce the exchange areas available for electrolysis, which in turn leads to increased cell resistance.

Description

The present invention relates to a method for producing an alkali metal alkoxide solution L ₁ in an electrolytic cell E.

The electrolytic cell E comprises at least one cathode chamber K _K , at least one anode chamber K _A and optionally a middle chamber K _M located in between. The interior I _KK of the cathode chamber K _K is separated by a partition wall W comprising at least one cation-conducting solid electrolyte ceramic F _A , for example NaSICON, from the interior I _KA of the anode chamber K _A or, in cases where the electrolytic cell E comprises a central chamber K _M , from Interior I _KM of the middle chamber K _M separated. If the electrolytic cell E comprises a central chamber K _M , the interior I _KM of the central chamber K _M is separated from the interior I _KA of the anode chamber _K A by a diffusion barrier D, for example a membrane selective for cations or anions or a non-ion-specific partition.

The part O _EA of the upper side O _E delimiting the interior I _KA of the anode chamber K _A is essentially designed as a plane whose normal N _OEA forms an angle 0°<φ _EA <45° to the gravitational vector V _S . In addition, the sequence A _KA is then arranged on the upper half of O _EA .

Alternatively or additionally, preferably additionally, the part O _EK of the upper side O _E delimiting the interior I _KK of the cathode chamber K _K is essentially designed as a plane whose normal N _OEK forms an angle 0°<φ _EK <45° to the gravity vector V _S , and the sequence A _KK is then arranged on the upper half of O _EK .

This arrangement of the respective upper sides and drains leads to the formation of gas cushions in the anode chamber being prevented. These gas cushions are undesirable because they reduce the exchange areas available for electrolysis, which in turn leads to increased cell resistance.

1. Background of the Invention

The electrochemical production of alkali metal alkoxide solutions is an important industrial process that is used, for example, in DE 103 60 758 A1 , the U.S. 2006/0226022 A1 and the WO 2005/059205 A1 is described. The principle of this process is reflected in an electrolytic cell in whose anode chamber there is a solution of an alkali salt, for example common salt or NaOH, and in whose cathode chamber there is the alcohol in question or a low-concentration alcoholic solution of the alkali metal alcoholate in question, for example sodium methoxide or sodium ethoxide. The cathode chamber and the anode chamber are separated by a ceramic that conducts the alkali metal ion used, for example NaSICON or an analog for potassium or lithium. When a current is applied, chlorine is formed at the anode - if a chloride salt of the alkali metal is used - and hydrogen and alcohol ions are formed at the cathode. The charge is equalized by the alkali metal ions migrating from the middle chamber into the cathode chamber via the ceramic that is selective for them. The charge equalization between the middle chamber and the anode chamber takes place through the migration of cations when using cation exchange membranes or the migration of anions when using anion exchange membranes or through the migration of both types of ions when using non-specific diffusion barriers. This increases the concentration of the alkali metal alcoholate in the cathode chamber and the concentration of the sodium ions in the anolyte decreases.

NaSICON solid electrolytes are also used in the electrochemical production of other compounds:
WO 2014/008410 A1 describes an electrolytic process for the production of elemental titanium or rare earths. This process is based on the fact that titanium chloride is formed from TiO ₂ and the corresponding acid, this reacts with sodium alcoholate to form titanium alcoholate and NaCl and is finally converted electrolytically to form elemental titanium and sodium alcoholate.

WO 2007/082092 A2 and WO 2009/059315 A1 describe processes for the production of biodiesel in which triglycerides are first converted into the corresponding alkali metal triglycerides with the aid of alcoholates electrolytically produced via NaSICON and in a second step are converted into glycerol and the respective alkali metal hydroxide with electrolytically produced protons.

A disadvantage of the electrolysis cells described in the prior art, however, is that gases are formed in the respective chambers during the electrolysis, since the electrolytes and gases are discharged from these only at certain points. As the generated gas rises in a dense manner in the electrolyte, it accumulates on the entire top of the electrolytic cell chambers. This gas-filled part of the chamber can no longer take part in the electrochemical conversion, since the gas cushions insulate the perpendicular chamber walls, which at the same time ensure the transfer of Na ⁺ ions. The reduction in the exchange areas also increases the resistance in the cell, since this is directly proportional to the passage areas. This also degrades the energy-specific data (current, voltage) of the cell and the entire process becomes economically unprofitable.

The object of the present invention was therefore to provide a process for preparing an alkali metal alkoxide solution in an electrolytic cell which does not have this disadvantage.

A further disadvantage of conventional electrolytic cells in this technical field results from the fact that the solid electrolyte is not stable over the long term with respect to aqueous acids. This is problematic insofar as the pH drops in the anode chamber during electrolysis as a result of oxidation processes (for example when halogens are produced by disproportionation or by oxygen formation). These acidic conditions attack the NaSICON solid electrolyte, so the process cannot be used on an industrial scale. Various approaches have been described in the prior art to address this problem.

Thus, three-chamber cells have been proposed in the prior art. Such are known in the field of electrodialysis, for example US 6,221,225 B1 .

WO 2012/048032 A2 and US 2010/0044242 A1 describe, for example, electrochemical processes for the production of sodium hypochlorite and similar chlorine compounds in such a three-chamber cell. The cathode chamber and the middle chamber of the cell are separated by a cation-permeable solid electrolyte such as NaSICON. In order to protect this from the acidic anolyte, the middle chamber is supplied with solution from the cathode chamber, for example. The US 2010/0044242 A1 also describes in Figure 6 that solution from the middle chamber can be mixed with solution from the anode chamber outside the chamber to obtain sodium hypochlorite.

Such cells have also been proposed in the prior art for the production or purification of alkali metal alkoxides.

That's how she describes it US 5,389,211A a process for the purification of alcoholate solutions in which a three-chamber cell is used, in which the chambers are separated from one another by cation-selective solid electrolytes or non-ionic partitions. The center compartment is used as a buffer compartment to prevent the purified alkoxide or hydroxide solution from the cathode compartment from mixing with the contaminated solution from the anode compartment.

The DE 42 33 191 A1 describes the electrolytic production of alcoholates from salts and alcoholates in multi-chamber cells and stacks of several cells.

The WO 2008/076327 A1 describes a process for preparing alkali metal alkoxides. A three-chamber cell is used, the middle chamber of which is filled with alkali metal alkoxide (see, for example, paragraphs [0008] and [0067] of WO 2008/076327 A1 ). This protects the solid electrolyte separating the middle chamber and the cathode chamber from the solution in the anode chamber, which becomes more acidic during the electrolysis. A similar arrangement is described in WO 2009/073062 A1 . However, this arrangement has the disadvantage that it is the alkali metal alkoxide solution, which is consumed as a buffer solution and is continuously contaminated is the desired product. Another disadvantage of the in the WO 2008/076327 A1 The method described is that the formation of the alcoholate in the cathode chamber depends on the diffusion rate of the alkali metal ions through two membranes or solid electrolytes. This in turn slows down the formation of the alcoholate.

Another problem arises from the geometry of the three-chamber cell. In such a chamber, the central chamber is separated from the anode chamber by a diffusion barrier and from the cathode chamber by an ion-conducting ceramic. During the electrolysis, this inevitably leads to the formation of pH gradients and dead volumes. This can damage the ion-conducting ceramic and consequently increase the voltage requirement of the electrolysis and/or lead to breakage of the ceramic.

While this effect takes place throughout the electrolysis chamber, the drop in pH is particularly critical in the middle chamber, as this is bounded by the ion-conducting ceramic. Gases are usually formed at the anode and the cathode, so that there is at least a certain degree of mixing in these chambers. On the other hand, such mixing does not take place in the middle chamber, so that the pH gradient develops in it. This undesirable effect is amplified by the fact that the brine is generally pumped relatively slowly through the electrolytic cell.

A further object of the present invention was therefore to provide an improved process for the electrolytic production of alkali metal alkoxide. These should not have the aforementioned disadvantages and should in particular ensure improved protection of the solid electrolyte against the formation of the pH gradient and more economical use of the educts compared to the prior art.

2. Summary of the Invention

The objects according to the invention are achieved by the method according to claim 1.

3. Pictures 3.1 Figures 1A and 1B

The figures 1 A (= " 1 A") and 1 B (= " 1 B") show the method according to the invention using an electrolytic cell E <1>, which is a two-chamber cell. The same electrolytic cell is shown in both figures from a different perspective 1 A shown perspective corresponds to the top view of the in Fig. 1B shown electrolytic cell E <1> in the direction of arrow <30>.

The electrolytic cell E <1> comprises a cathode chamber K _K <12> and an anode chamber K _A <11>.

The anode chamber K _A <11> comprises an anodic electrode E _A <113> in the interior I _KA <112>, an inlet Z _KK <110> and an outlet A _KA <111>.

The cathode chamber K _K <12> comprises a cathodic electrode E _K <123> in the interior I _KK <122>, an inlet Z _KK <120> and an outlet A _KK <121>.

The electrolytic cell E <1> forms a container B _E <800> on the side and on the bottom and a flat upper side O _E <801> on top. The interior I _KA <112> is delimited by a part O _EA <8011> of the upper side O _E <801> and a part B _EA <8001> of the container B _E <800>. The interior I _KK <122> is delimited by a part O _EK <8012> of the upper side O _E <801> and a part B _EK <8002> of the container B _E <800>.

The interior I _KK <122> is also separated from the interior I _KA <112> by a partition wall W <16>, which consists of a disk of a NaSICON solid electrolyte _FA <18> that is selectively permeable for sodium ions. The NaSlCON solid electrolyte _FA <18> extends over the entire depth and height of the two-chamber cell E. The NaSlCON solid electrolyte _FA <18> contacts the two interior spaces I _KK <122> and I _KA <112> directly, so that sodium ions can be conducted from one interior to the other through the NaSICON solid electrolyte F _A <18>.

How out Fig. 1B As can be seen, the electrolytic cell E <1> is inclined, which means that the flat upper side O _E <801> and thus also the two parts O _EA <8011> and O _EK <8012> are inclined. The angle ϕ _EA or ϕ _EK of the respective normal N _OEA <91> and N _OEK <92> of the plane O _EA <8011> and O _EK <8012> compared to the vector of gravity V _s <90> is ~ 25 °. The two drains A _KA <111> and A _KK <121> are located close to the highest edge of the electrolytic cell E <1>.

An aqueous solution of sodium chloride L ₃ <23> with pH 10.5 is added counter to gravity into the interior I _KA <112> via the inlet Z _KA <110>.

A solution of sodium methoxide in methanol L ₂ <22> is fed into the interior space I _KK <122> via the inlet Z _KK <120>.

A voltage is applied between the cathodic electrode E _K <123> and the anodic electrode E _A <113>. As a result, in the interior I _KK <122>, methanol is reduced to methoxide and H ₂ in the electrolyte L ₂ <22> (CH ₃ OH + e ^- →CH ₃ O ^- + ½ H ₂ ). Sodium ions diffuse from the interior I _KA <112> through the NaSICON solid electrolyte _FA <18> into the interior I _KK <122>. Overall, this increases the concentration of sodium methoxide in the Interior I _KK <122>, giving a methanolic solution of sodium methoxide L ₁ <21>, the concentration of sodium methoxide in which is increased compared to L ₂ <22>.

In the interior I _KA <112> the oxidation of chloride ions to molecular chlorine takes place (Cl ^- → ½ Cl ₂ + e ^- ). At the outflow A _KA <111>, an aqueous solution L ₄ <24> is obtained in which the NaCl content is reduced compared to L ₃ <23>. Chlorine gas Cl ₂ forms hypochlorous acid and hydrochloric acid in water according to the reaction Cl ₂ + H ₂ O → HOCl + HCl, which reacts acidically with other water molecules. The acidity damages the NaSICON solid electrolyte F _A <18>.

Due to the inclined inclination of the electrolytic cell E <1> and the arrangement of the outlets A _KA <111> and A _KK <121> close to their highest point or their highest edge, gases that form (e.g. chlorine gas in the anode chamber K _A <11 > And hydrogen gas in the cathode chamber K _K <12>) discharged efficiently and quickly, thereby preventing the formation of a gas cushion. The rapid removal of the chlorine gas also reduces the acid-forming reaction Cl ₂ + H ₂ O → HOCl + HCl and thus the increase in acidity in the anode chamber K _A <11 >, which in turn extends the service life of the NaSICON solid electrolyte.

3.2 Figures 2A and 2B

The figures 2 A (= " 2 A") and 2 B (= " 2 B") show a further embodiment of the method according to the invention. They show the method according to the invention using an electrolytic cell E <1>, which is a three-chamber cell. The same electrolytic cell is shown in both figures from a different perspective Fig. 2A The perspective shown corresponds to the top view of the in Fig. 2B shown electrolytic cell E <1> in the direction of arrow <30>.

The three-chamber electrolytic cell E comprises a cathode chamber K _K <12>, an anode chamber K _A <11> and a middle chamber K _M <13> located in between.

The anode chamber K _A <11> comprises an anodic electrode E _A <113> in the interior I _KA <112>, an inlet Z _KK <110> and an outlet A _KA <111>.

The cathode chamber K _K <12> comprises a cathodic electrode E _K <123> in the interior I _KK <122>, an inlet Z _KK <120> and an outlet A _KK <121>.

The central chamber K _M <13> comprises an interior space I _KM <132>, an inlet Z _KM <130> and an outlet A _KM <131>. The interior space I _KA <112> is connected to the interior space I _KM <132> via the connection V _AM <15>.

The electrolytic cell E <1> forms a container B _E <800> on the side and on the bottom and a flat upper side O _E <801> on top. The interior I _KA <112> is delimited by a part O _EA <8011> of the upper side O _E <801> and a part B _EA <8001> of the container B _E <800>. The interior I _KK <122> is defined by a part O _EK <8012> of the upper side O _E <801> and a part B _EK <8002> of container B _E <800> limited. The interior space I _KM <132> is delimited by a part O _EM <8013> of the upper side O _E <801> and a part B _EM <8003> of the container B _E <800>.

The interior I _KK <122> is also separated from the interior I _KM <132> by a partition W <16>, which consists of a disk of a NaSICON solid electrolyte _FA <18> that is selectively permeable for sodium ions. The NaSlCON solid electrolyte _FA <18> extends over the entire depth and height of the three-chamber cell E. The NaSlCON solid electrolyte _FA <18> contacts the two inner spaces I _KK <122> and I _KM <132> directly, so that sodium ions can be conducted from one interior to the other through the NaSICON solid electrolyte F _A <18>.

The interior I _KM <132> of the middle chamber K _M <13> is additionally separated from the interior I _KA <112> of the anode chamber _KA <11> by a diffusion barrier D <14>. The NaSlCON solid electrolyte F _A <18> and the diffusion barrier D <14> extend over the entire depth and height of the three-chamber cell E. The diffusion barrier D <14> is a cation exchange membrane (sulfonated PTFE).

In the embodiment according to Figures 2A and 2B, the connection V _AM <15> is formed outside the electrolytic cell E , in particular by a tube or hose, the material of which can be chosen from rubber, metal or plastic. Through the connection V _AM <15>, liquid can be conducted from the interior I _KM <132> of the central chamber K _M <13> into the interior I _KA <112> of the anode chamber _KA <11> outside the three-chamber cell E <1>. The connection V _AM <15> connects an outlet A _KM <131>, which breaks through the container B _E <800> of the electrolytic cell E at the bottom of the central chamber K _M <13>, with an inlet Z _KA <110>, which is at the bottom of the anode chamber K _A <11> breaks through the container B _E <800> of the electrolytic cell E.

How out Fig. 2B As can be seen, the electrolytic cell E <1> is inclined, which means that the flat upper side O _E <801> and thus also the two parts O _EA <8011> and O _EK <8012> are inclined. The two drains A _KA <111> and A _KK <121> are located close to the highest edge of the electrolytic cell E <1>. The angle ϕ _EA or ϕ _EK of the respective normal N _OEA <91> and N _OEK <92> of the plane O _EA <8011> and O _EK <8012> compared to the vector of gravity V _S <90> is ∼ 25 °.

An aqueous solution of sodium chloride L ₃ <23> with pH 10.5 is added via the inlet Z _KM <130> in the same direction as gravity into the interior I _KM <132> of the central chamber K _M <13>. The interior space I KM <132 is formed by the connection V _AM <15>, which is formed between the outlet A _KM <131> of the _central chamber K _M <13> and an inlet Z _KA <110> of the anode chamber _KA <11>> of the middle chamber K _M <13> connected to the interior I _KA <112> of the anode chamber K _A <11>. Sodium chloride solution L ₃ <23> is conducted through this connection V _AM <15> from interior I _KM <132> to interior I _KA <112>.

A solution of sodium methoxide in methanol L ₂ <22> is fed into the interior space I _KK <122> via the inlet Z _KK <120>.

A voltage is applied between the cathodic electrode E _K <123> and the anodic electrode E _A <113>. As a result, in the interior I _KK <122>, methanol in the electrolyte L ₂ <22> is reduced to methoxide and H ₂ (CH ₃ OH + e ^- → CH ₃ O ^- + ½ H ₂ ). Sodium ions diffuse from the interior I _KM <132> of the middle chamber K _M <103> through the NaSICON solid electrolyte _FA <18> into the interior I _KK <122>. Overall, this increases the concentration of sodium methoxide in the interior I _KK <122>, as a result of which a methanolic solution of sodium methoxide L ₁ <21> is obtained, the concentration of sodium methoxide being higher than that of L ₂ <22>.

In the interior I _KA <112> the oxidation of chloride ions to molecular chlorine takes place (Cl ^- → ½ Cl ₂ + e ^- ). At the outflow A _KA <111>, an aqueous solution L ₄ <24> is obtained in which the NaCl content is reduced compared to L ₃ <23>. Chlorine gas Cl ₂ forms hypochlorous acid and hydrochloric acid in water according to the reaction Cl ₂ + H ₂ O → HOCl + HCl, which reacts acidically with other water molecules. The acidity would damage the NaSICON solid electrolyte _FA <18>, but is limited to the anode chamber _KA <11> by the arrangement in the three-chamber cell and is thus kept away from the NaSICON solid electrolyte _FA <18> in the electrolytic cell E. This increases its lifespan considerably.

Due to the inclined inclination of the electrolytic cell E <1> and the arrangement of the outlets A _KA <111> and A _KK <121> close to their highest point or their highest edge, gases that form (e.g. chlorine gas in the anode chamber K _A <11 > And hydrogen gas in the cathode chamber K _K <12>) discharged efficiently and quickly, thereby preventing the formation of a gas cushion. The rapid removal of the chlorine gas also reduces the acid-forming reaction Cl ₂ + H ₂ O → HOCl + HCl and thus the increase in acidity in the anode chamber K _A <11 >, which in turn extends the service life of the NaSICON solid electrolyte.

3.3 Figures 3A and 3B

The figures 3 A (= " 3 A") and 3 B (= " 3 B") show a further embodiment of the method according to the invention. This is carried out in an electrolytic cell E <1>, which corresponds to the electrolytic cell E <1> shown in Figures 2 A and 2 B with the following difference:
The connection V _AM <15> from the interior I _KM <132> of the middle chamber K _M <13> to the interior I _KA <112> of the anode chamber K _A <11> is not outside, but through a perforation in the diffusion barrier D <14> formed within the electrolytic cell E <1>. This perforation can be introduced into the diffusion barrier D <14> subsequently (e.g. by punching, drilling) or are already present in the diffusion barrier D <14> from the outset due to the production thereof (e.g. in the case of textile fabrics such as filter cloths or metal fabrics).

3.4 Figure 4

Figure 4 (= " 4 ") shows a further embodiment of the method according to the invention. It shows the method according to the invention using an electrolytic cell E <1>, which is a two-chamber cell.

This corresponds to the electrolytic cell E <1> shown in Figures 1 A and 1 B and differs from it in terms of the geometric relationships. In the electrolytic cell E <1> according to Figures 1A and 1B the bottom and top O _E <801> are substantially parallel planes and the interiors I _KK <122> and I _KA <112> are substantially in the shape of a parallelepiped. The inclination of the top O _E <801> is ensured by the inclination of the entire electrolytic cell E <1>.

In contrast, the top is O _E <801> in the electrolytic cell E <1> in 4 not parallel to the ground, and the interiors I _KK <122> and I _KA <112> have a trapezoidal section. The angle ϕ _EA or ϕ _EK of the respective normal N _OEA <91> and N _OEK <92> of the plane O _EA <8011> and O _EK <8012> compared to the vector of gravity V _s <90> is ~ 11 °. This has the advantage that the entire electrolytic cell E <1> does not have to be inclined, and the two planes O _EA <8011> and O _EK <8012> nevertheless form the inclination according to the invention. This gives the structure greater stability.

3.5 Figure 5

Figure 5 (= " figure 5 ") shows a further embodiment of the method according to the invention. It shows the method according to the invention using an electrolytic cell E <1>, which is a three-chamber cell.

This corresponds to the electrolytic cell E <1> shown in Figures 2 A and 2 B and differs from it in the geometric relationships: In the electrolytic cell E <1> according to Figures 2A and 2B the bottom and top O _E <801> are substantially parallel planes and the interiors I _KK <122>, I _KA <112> and I _KM <132> are substantially in the shape of a cuboid. The inclination of the top O _E <801> is ensured by the inclination of the entire electrolytic cell E <1>.

In contrast, the top is O _E <801> in the electrolytic cell E <1> in figure 5 not parallel to the ground, and the interiors I _KK <122>, I _KA <112> and I _KM <132> have a trapezoidal section. The angle ϕ _EA or ϕ _EK of the respective normals N _OEA <91> and N _OEK <92> the plane O _EA <8011> and O _EK <8012> compared to the vector of gravity V _S <90> is ∼ 11°.

This has the advantage that the entire electrolytic cell E <1> does not have to be inclined, and the two planes O _EA <8011> and O _EK <8012> nevertheless form the inclination according to the invention. This gives the structure greater stability.

3.6 Figure 6

Figure 6 (= " 6 ") shows an embodiment of the method not according to the invention. In it, a two-chamber electrolytic cell E is used as described for Figures 1 A and 1 B, except that these are not inclined and the two processes A _KA <111 > and A _KK <121 > in is arranged in the middle of the respective plane O _EA <8011> and O _EK <8012>.

3.7 Figure 7

Figure 7 (= " 7 ") shows an embodiment of the method not according to the invention. In it, a three-chamber electrolytic cell E is used as described for Figures 2 A and 2 B, except that these are not inclined and the two processes A _KA <111 > and A _KK <121 > in is arranged in the middle of the respective plane O _EA <8011> and O _EK <8012>.

4. Detailed Description of the Invention 4.1 Electrolytic cell E

The method according to the invention is carried out in an electrolytic cell E.

The electrolytic cell E comprises at least one anode chamber K _A and at least one cathode chamber K _K and optionally at least one intermediate chamber K _M . This also includes electrolytic cells E which have more than one anode chamber K _A and/or more than one cathode chamber K _K and/or more than one middle chamber K _M . Such electrolytic cells, in which these chambers are joined together in a modular manner, are, for example, in DD 258 143 A3 and the U.S. 2006/0226022 A1 described.

In a preferred embodiment of the invention, the electrolytic cell E comprises an anode chamber K _A and a cathode chamber K _K and optionally a middle chamber K _M located in between.

The electrolytic cell E forms a container B _E and a top O _E from.

The container B _E and the upper side O _E each comprise, independently of one another, in particular a material which is selected from the group consisting of steel, preferably rubberized steel, plastic, which is in particular made from ^Telene® (thermosetting polydicyclopentadiene), PVC (polyvinyl chloride), PVC-C ( post-chlorinated polyvinyl chloride), PVDF (polyvinylidene fluoride). The container B _E and the top O _E preferably comprise the same material. Even more preferably, they are then at least partially in one piece, ie at least part of the container B _E forms one piece with at least part of the upper side O _E .

The container B _E and the top O _E are perforated in particular for inlets and outlets.

The container B _E and the top O _E form the outer wall W _A of the electrolytic cell E.

Within _BE and _OE are the at least one anode chamber K _A , the at least one cathode chamber K _K and, in the embodiments in which the electrolytic cell E comprises such, the at least one intermediate intermediate chamber K _M . The container B _E forms the bottom and the side walls of the electrolytic cell E. The container B _E thus also forms the bottom and the side walls of the at least one anode chamber K _A that it encompasses, of the at least one cathode chamber K _K that it encompasses and in the embodiments , In which the electrolytic cell E includes such a cell, which includes at least one intermediate chamber K _M . In this case, the base preferably essentially forms a plane, and each of the side walls in each case more preferably also essentially forms a plane.

The upper side O _E is in particular formed essentially as a plane. "Top" implies that the lowest point of the plane defined by the top O _E is higher (i.e. further from the center of the earth) than the lowest point of the container B _E .

In a preferred embodiment, the container B _E and the top O _E essentially form a polyhedron, preferably a hexahedron, in which at least one pair, preferably at least two pairs of opposite sides are parallel to one another. Even more preferably, the container B _E and the top O _E essentially form a cuboid. In this embodiment, the electrolytic cell E is then arranged so that there is a face of the polyhedron on which the highest point (ie furthest from the center of the earth) of the polyhedron lies and whose lowest point is higher than the lowest point of the remaining sides. In this embodiment, this surface is then the upper side O _E of the electrolytic cell E, the remaining surfaces form the container B _E .

4.1.1 Cathode Chamber K _K

The cathode chamber K _K has at least one inlet Z _KK , at least one outlet A _KK and an interior space I _KK , which includes a cathodic electrode E _K . The interior I _KK is delimited by a part O _EK of the upper side O _E and a part B _EK of the container B _E . Accordingly, the part of the upper side O _E that delimits I _KK is referred to as O _EK , and the part of the container B _E that delimits I _KK is referred to as B _EK .

The interior I _KK of the cathode chamber K _K is separated by the partition W from the interior I _KA of the anode chamber K _A if the electrolytic cell E does not include a central chamber K _M .

The partition W comprises at least one solid electrolyte ceramic F _A which conducts alkali cations, and the solid electrolyte ceramics which conduct alkali cations comprised by the partition W then contact the interior space I _KK and the interior space I _KA directly.

The interior I _KK of the cathode chamber K _K is separated by the partition W from the interior I _KM of the middle chamber K _M if the electrolytic cell E comprises at least one middle chamber K _M .

The solid electrolyte ceramics which conduct alkali cations and are enclosed by the partition W then make direct contact with the interior space I _KK and the interior space I _KM .

4.1.1.1 Partition wall W

The partition wall W comprises at least one solid electrolyte ceramic F _A which conducts alkali cations. The feature "partition wall" means that the partition wall W is liquid-tight. This means in particular that the dividing wall comprises either an alkali cation-conducting solid electrolyte ceramic that completely separates the interior space I _KK and the interior space I _KM or the interior space I _KK and the interior space I _KA from one another, or comprises several alkali cation-conducting solid electrolyte ceramics which, for example, adjoin one another without gaps.

In any case, there are no gaps in the partition W through which aqueous solution, alcoholic solution, alcohol or water could flow from I _KK to I _AK or from I _KK to I _MK or vice versa.

"Contact directly" means for the arrangement of the alkali cation-conducting solid electrolyte ceramics in the partition W and in the electrolytic cell E that there is an imaginary path from I _KK to I _AK or from I _KK to I _MK for each alkali cation-conducting solid electrolyte ceramic contained in the partition W There, which leads completely through the respective alkali cation-conducting solid electrolyte ceramic.

4.1.1.2 Alkaline cation-conducting solid electrolyte ceramics

Any solid electrolyte through which cations, in particular alkali cations, more preferably sodium cations, can be transported from I _AK to I _KK or from I _MK to I _KK can _be considered as the at least one solid electrolyte ceramic FA that conducts alkali cations. Such solid electrolytes are known to those skilled in the art and, for example, in DE 10 2015 013 155 A1 , in the WO 2012/048032 A2 , paragraphs [0035], [0039], [0040], in the US 2010/0044242 A1 , paragraphs [0040], [0041], in which DE 10360758 A1 , paragraphs [014] to [025]. They are sold commercially under the names NaSICON, LiSICON, KSICON. A sodium ion conductive solid electrolyte is preferred, more preferably having a NaSICON structure. NaSICON structures that can be used according to the invention are also described, for example, by Anantharamulu N, Koteswara Rao K, Rambabu G, Vijaya Kumar B, Velchuri Radha, Vithal M, J Mater Sci 2011, 46, 2821-2837 .

In a preferred embodiment of the dividing wall W , the alkali cation-conducting solid electrolyte ceramics comprised by the dividing wall W independently of one another have a NaSICON structure of the formula M ^I _1+2w+x-y+z M ^II _w MI ^II _x Zr ^IV _2-wxy M ^V _y (SiO ₄ ) _z (PO ₄ ) _3-z on.

M ^I is selected from Na ⁺ , Li ⁺ , preferably Na ⁺ .

M ^II is a divalent metal cation, preferably selected from Mg ²⁺ , Ca ²⁺ , Sr ²⁺ , Ba ²⁺ , CO ²⁺ , Ni ²⁺ , more preferably selected from Co ²⁺ , Ni ²⁺ .

M ^III is a trivalent metal cation, preferably selected from Al ³⁺ , Ga ³⁺ , Sc ³⁺ , La ³⁺ , Y ³⁺ , Gd ³⁺ , Sm ³⁺ , Lu ³⁺ , Fe ³⁺ , Cr ³⁺ , more preferably selected from Sc ³⁺ , La ³⁺ , Y ³⁺ , Gd ³⁺ , Sm ³⁺ , particularly preferably selected from Sc ³⁺ , Y ³⁺ , La ³⁺ .

M ^V is a pentavalent metal cation, preferably selected from V ⁵⁺ , Nb ⁵⁺ , Ta ⁵⁺ .

The Roman indices I, II, III, IV, V indicate the oxidation numbers in which the respective metal cations are present.

w, x, y, z are real numbers, where 0 ≤ x < 2, 0 ≤ y < 2, 0 ≤ w < 2, 0 ≤ z < 3, and where w, x, y, z are so chosen become that 1 + 2w + x - y + z ≥ 0 and 2 - w - x - y ≥ 0.

According to the invention, the NaSICON structure more preferably has a structure of the formula Na _(1+v ) _{Zr2SivP (3-v) O12} , where v is _a real number for which 0≦v≦3 applies. Most preferably v = 2.4

In a preferred embodiment of the method according to the invention, the alkali cation-conducting solid electrolyte ceramics comprised by the partition W have the same structure.

4.1.1.3 Cathodic Electrode E _K

The cathode chamber K _K includes an interior space I _KK , which in turn includes a cathodic electrode E _K . Any electrode familiar to a person skilled in the art that is stable under the conditions of the method according to the invention can be used as such a cathodic electrode E _K . Such are in particular in WO 2014/008410 A1 , paragraph [025] or DE 10360758 A1 , paragraph [030]. This electrode E _K can be selected from the group consisting of mesh wool, three-dimensional matrix structure or "balls". The cathodic electrode E _K comprises in particular a material which is selected from the group consisting of steel, nickel, copper, platinum, platinized metals, palladium, palladium supported on carbon, titanium. E _K preferably comprises nickel.

4.1.1.4 Inflow Z _KK and process A _KK

The cathode chamber K _K also includes an inlet Z _KK and an outlet A _KK . This makes it possible to add liquid, such as solution L ₂ , to the inner space I _KK of the cathode chamber K _K and to remove liquid, such as solution L ₁ , located therein. The inlet Z _KK and the outlet A _KK are attached to the cathode chamber K _K in such a way that the liquid makes contact with the cathodic electrode E _K as it flows through the interior I _KK of the cathode chamber _{K K} . This is the prerequisite for the solution L ₁ being obtained at the outlet A _KK when the process according to the invention is carried out when the solution L ₂ of an alkali metal alkoxide XOR in the alcohol ROH is passed through the interior I _KK of the cathode chamber K _K .

The inlet Z _KK and the outlet A _KK can be attached to the electrolytic cell E by methods known to those skilled in the art, for example through holes in the container part B _EK or the top part O _EK and corresponding connections (valves) that allow the introduction or discharge of simplify fluid.

Essential to the invention, the sequence A _KK is arranged at O _EK .

4.1.2 Anode chamber KA

The anode chamber K _A has at least one inlet Z _KA , at least one outlet A _KA and an interior space I _KA , which includes an anodic electrode E _A . The interior I _KA is delimited by a part O _EA of the upper side O _E and a part B _EA of the container B _E . Accordingly, the part of the top O _E that delimits I _KA is referred to as O _EA and the part of the container B _E that delimits I _KA is referred to as B _EA .

The interior space I _KA of the anode chamber K _A is separated from the interior space I _KM of the center chamber K _M by a diffusion barrier D if the electrolytic cell E includes a central chamber K _M . If the electrolytic cell E does not include a middle chamber K _M , the interior space I _KA of the anode chamber K is separated by the partition wall W from the interior space I _KK of the cathode chamber K _K .

4.1.2.1 Anodic Electrode E _A

The anode chamber K _A includes an interior space I _KA , which in turn includes an anodic electrode E _A . Any electrode familiar to a person skilled in the art that is stable under the conditions of the method according to the third aspect of the invention can be used as such an anodic electrode E _A . Such are in particular in WO 2014/008410 A1 , paragraph [024] or DE 10360758 A1 , paragraph [031]. This electrode E _A can consist of one layer or of several planar, mutually parallel layers, each of which can be perforated or expanded. The anodic electrode E _A comprises in particular a material which is selected from the group consisting of ruthenium oxide, iridium oxide, nickel, cobalt, nickel tungstate, nickel titanate, noble metals such as platinum in particular, which is deposited on a carrier such as titanium or ^Kovar® (an iron/nickel/ Cobalt alloy, in which the individual proportions are preferably as follows: 54% by mass iron, 29% by mass nickel, 17% by mass cobalt) is supported. Other possible anode materials are, in particular, stainless steel, lead, graphite, tungsten carbide, titanium diboride. The anodic electrode E _A preferably comprises a titanium anode (RuO ₂ + IrO ₂ /Ti) coated with ruthenium oxide/iridium oxide.

4.1.2.2 Inlet Z _KA and outlet A _KA

The anode chamber K _A also includes an inlet Z _KA and an outlet A _KA . This makes it possible to add liquid, such as solution L ₃ , to the interior space I _KA of the anode chamber K _A and to remove liquid, such as solution L ₄ , located therein. The inlet Z _KA and the outlet A _KA are attached to the anode chamber K _A in such a way that the liquid makes contact with the anodic electrode E _A as it flows through the interior space I _KA of the anode chamber K _A . This is the prerequisite for the solution L ₄ being obtained at the outlet A _KA when the method according to the invention is carried out if the solution L ₃ of a salt S is passed through the interior space I _KA of the anode chamber _KA .

The inlet Z _KA and the outlet _{A KA} can be attached to the electrolytic cell E by methods known to those skilled in the art, _e simplify fluid. In certain embodiments, in which the electrolytic cell E comprises a central chamber K _M , the inlet Z _KA can also lie within the electrolytic cell, for example as a perforation in the diffusion barrier D.

Essential to the invention, the sequence A _KA is arranged at O _EA .

4.1.3 Optional center chamber K _M

The electrolytic cell E preferably has a central chamber K _M . The optional middle chamber K _M is located between the cathode chamber K _K and the anode chamber K _A . It comprises at least one inlet Z _KM , at least one outlet A _KM and an interior I _KM . The interior I _KM is delimited by a part O _EM of the upper side O _E and a part B _EM of the container B _E . Accordingly, the part of the top O _E that delimits I _KM is referred to as O _EM and the part of the container B _E that delimits I _KM is referred to as B _EM .

The interior space I _KA of the anode chamber K _A is separated from the interior space I _KM of the center chamber K _M by a diffusion barrier D if the electrolytic cell E includes a central chamber K _M . A _KM is then also connected to the inlet Z _KA by a connection V _AM , so that liquid can be conducted from I _KM into I _KA through the connection V _AM .

4.1.3.1 Diffusion barrier D

The interior I _KM of the optional central chamber K _M is separated from the interior I _KA of the anode chamber K _A by a diffusion barrier D and from the interior I _KK of the cathode chamber K _K by the partition wall W.

Any material which is stable under the conditions of the method according to the invention and which prevents or slows down the transfer of protons from the liquid in the interior I _KA of the anode chamber K _A to the interior I _KM of the optional middle chamber K _M can be used for the diffusion barrier D.

In particular, a non-ion-specific dividing wall or a membrane permeable to specific ions is used as the diffusion barrier D. The diffusion barrier D is preferably a non-ion-specific partition.

The material of the non-ion-specific partition wall is in particular selected from the group consisting of fabric, in particular textile fabric or metal fabric, glass, in particular sintered glass or glass frits, ceramic, in particular ceramic frits, membrane diaphragms, and is selected particularly preferably a textile fabric or metal fabric, particularly preferably a textile fabric. The textile fabric preferably comprises plastic, more preferably a plastic selected from PVC, PVC-C, polyvinyl ether ("PVE"), polytetrafluoroethylene ("PTFE").

If the diffusion barrier D is a “membrane that is permeable to specific ions”, this means according to the invention that the respective membrane favors the diffusion of certain ions through it compared to other ions. In particular, membranes are meant that oppose the diffusion through them of ions of a certain type of charge favor oppositely charged ions. More preferably, specific ion permeable membranes also favor the diffusion of certain ions having one charge type through them over other ions of the same charge type.

If the diffusion barrier D is a “membrane permeable to specific ions”, the diffusion barrier D is in particular an anion-conducting membrane or a cation-conducting membrane.

According to the invention, anion-conducting membranes are those which selectively conduct anions, preferably selectively specific anions. In other words, they favor the diffusion of anions through them over that of cations, especially over protons, more preferably they additionally favor the diffusion of certain anions through them over the diffusion of other anions through them.

According to the invention, cation-conducting membranes are those which selectively conduct cations, preferably selectively specific cations. In other words, they favor the diffusion of cations through them over that of anions, more preferably they additionally favor the diffusion of certain cations through them over the diffusion of other cations through them, much more preferably cations where there is are not protons, more preferably sodium cations, over protons.

“Favour the diffusion of certain ions X compared to the diffusion of other ions Y” means in particular that the diffusion coefficient (unit m ² /s) of the ion species X at a given temperature for the membrane in question is higher by a factor of 10, preferably 100, preferably 1000 as the diffusion coefficient of the ionic species Y for the membrane in question.

If the diffusion barrier D is a “membrane that is permeable to specific ions”, it is preferably an anion-conducting membrane because this prevents the diffusion of protons from the anode chamber K _A into the middle chamber K _M particularly well.

In particular, a membrane which is selective for the anions comprised by the salt S is used as the anion-conducting membrane. Such membranes are known to those skilled in the art and can be used by them.

The salt S is preferably a halide, sulfate, sulfite, nitrate, bicarbonate or carbonate of X, more preferably a halide.

Halides are fluorides, chlorides, bromides, iodides. The most preferred halide is chloride.

A membrane selective for halides, preferably chloride, is preferably used as the anion-conducting membrane.

Anion-conducting membranes are, for example, from MA Hickner, AM Herring, EB Coughlin, Journal of Polymer Science, Part B: Polymer Physics 2013, 51, 1727-1735 , by CG Arges, V Ramani, PN Pintauro, Electrochemical Society Interface 2010, 19, 31-35 ,
in WO 2007/048712 A2 as well as on Page 181 of the textbook by Volkmar M. Schmidt Electrochemical Process Engineering: Fundamentals, Reaction Engineering, Process Optimization, 1st edition (October 8, 2003 ) described.

Organic polymers, which are selected in particular from polyethylene, polybenzimidazoles, polyetherketones, polystyrene, polypropylene or fluorinated membranes such as polyperfluoroethylene, preferably polystyrene, are therefore even more preferably used as the anion-conducting membrane, with these covalently bonded functional groups selected from -NH ₃ ⁺ , - NRH ₂ ⁺ , -NR ₃ ⁺ , =NR ⁺ ;-PR ₃ ⁺ , where R is an alkyl group preferably having 1 to 20 carbon atoms, or other cationic groups. Preferably they have covalently bonded functional groups selected from -NH ₃ ⁺ , -NRH ₂ ⁺ , -NR ₃ ⁺ , more preferably selected from -NH ₃ ⁺ , -NR ₃ ⁺ , even more preferably -NR ₃ ⁺ .

If the diffusion barrier D is a cation-conducting membrane, it is in particular a membrane that is selective for the cations comprised by the salt S. The diffusion barrier D is even more preferably an alkali cation-conducting membrane, even more preferably a potassium and/or sodium ion-conducting membrane, most preferably a sodium ion-conducting membrane.

Cation-conducting membranes are described, for example, on page 181 of the textbook by Volkmar M. Schmidt Electrochemical Process Engineering: Fundamentals, Reaction Engineering, Process Optimization, 1st edition (October 8, 2003 ).

Accordingly, organic polymers, which are selected in particular from polyethylene, polybenzimidazoles, polyetherketones, polystyrene, polypropylene or fluorinated membranes such as polyperfluoroethylene, preferably polystyrene, polyperfluoroethylene, are even more preferably used as the cation-conducting membrane, with these covalently bonded functional groups selected from -SO ₃ ^- , -COO ^- , -PO ₃ ^2- , -PO ₂ H ^- , preferably -SO ₃ ^- , (described in DE 10 2010 062 804 A1 , U.S. 4,831,146 ) carry.

This can be, for example, a sulfonated polyperfluoroethylene (Nafion ^® with CAS number: 31175-20-9 ) be. These are the expert, for example, from WO 2008/076327 A1 , paragraph [058], US 2010/0044242 A1 , paragraph [0042] or the U.S. 2016/0204459 A1 known and commercially available under the trade names ^Nafion® , ^Aciplex® F, ^Flemion® , ^Neosepta® , ^Ultrex® , PC- ^SK® . Neosepta ^® membranes are described, for example, by SA Mareev, D.Yu. Butylskii, ND Pismenskaya, C Larchet, L Dammak, VV Nikonenko, Journal of Membrane Science 2018, 563, 768-776 .

If a cation-conducting membrane is used as the diffusion barrier D , this can be, for example, a polymer functionalized with sulfonic acid groups, in particular of the following formula P _NAFION , where n and m independently of one another are an integer from 1 to 10 ⁶ , more preferably an integer from 10 to 10 ⁵ , more preferably is an integer from 10 ² to 10 ⁴ .

4.1.3.2 Inlet Z _KM and outlet A _KM

The optional middle chamber K _M also includes an inlet Z _KM and an outlet A _KM . This makes it possible to add liquid, such as solution L ₃ , to the interior space I _KM of the middle chamber K _M , and to transfer liquid therein, such as solution L ₃ , to the anode chamber K _A .

The inlet Z _KM and the outlet A _KM can be attached to the electrolytic cell E by methods known to those skilled in the art, for example through holes in the container part B _EM or the top part O _EM and corresponding connections (valves) that allow the introduction or discharge of simplify fluid. The drain A _KM can also be within the electrolytic cell, for example as a perforation in the diffusion barrier D.

4.1.3.3 Connection V _AM

1. 1) Ist die Verbindung V_AM innerhalb der Elektrolysezelle E ausgebildet, wird sie bevorzugt durch mindestens eine Perforation in der Diffusionsbarriere D gebildet. Diese Ausführungsform ist insbesondere dann bevorzugt, wenn als Diffusionsbarriere D eine nicht ionenspezifische Trennwand, insbesondere ein Metallgewebe oder textiles Gewebe eingesetzt wird. Dieses fungiert als Diffusionsbarriere D und weist aufgrund der Webeigenschaften von vorneherein Perforationen und Lücken auf, die als Verbindung V_AM fungieren.
2. 2) Die folgend beschriebene Ausführungsform ist insbesondere dann bevorzugt, wenn als Diffusionsbarriere D eine für spezifische Ionen durchlässige Membran eingesetzt wird: In dieser Ausführungsform ist die Verbindung V_AM außerhalb der Elektrolysezelle E ausgebildet, wobei sie bevorzugt durch eine außerhalb der Elektrolysezelle E verlaufende Verbindung von A_KM und Z_KA gebildet wird, insbesondere dadurch, dass vom Innenraum der Mittelkammer I_KM ein Ablauf A_KM, bevorzugt am Boden der Mittelkammer K_M, wobei noch bevorzugter der Zulauf Z_KM an der Oberseite O_EM der Mittelkammer K_M ist, gebildet wird, und ein Zulauf Z_KA in den Innenraum I_KA der Anodenkammer K_A, bevorzugt am Boden der Anodenkammer K_A, gebildet wird, und diese durch eine Leitung, beispielsweise ein Rohr oder ein Schlauch, der bevorzugt ein Material ausgewählt aus Gummi, Kunststoff umfasst, verbunden sind. Dies ist insbesondere deshalb vorteilhaft, da der Ablauf A_KA erfindungsgemäß an der Oberseite O_EA der Anodenkammer K_A ausgebildet.
   "Ablauf A_KM am Boden der Mittelkammer K_M " bedeutet insbesondere, dass der Ablauf A_KM so an der Elektrolysezelle E angebracht ist, dass die Lösung L₃ die Mittelkammer K_M gleichgerichtet mit der Schwerkraft verlässt.
   "Zulauf Z_KA am Boden der Anodenkammer K_A " bedeutet insbesondere, dass der Zulauf Z_KA so an der Elektrolysezelle E angebracht ist, dass die Lösung L₃ in die Anodenkammer K_A entgegen der Schwerkraft eintritt.
   "Zulauf Z_KM an der Oberseite O_EM der Mittelkammer K_M " bedeutet insbesondere, dass der Zulauf Z_KM so an der Elektrolysezelle E angebracht ist, dass die Lösung L₃ in die Mittelkammer K_M gleichgerichtet mit der Schwerkraft eintritt.
   "Ablauf A_KA an der Oberseite O_EA der Anodenkammer K_A " bedeutet insbesondere, dass der Ablauf A_KA so an der Elektrolysezelle E angebracht ist, dass die Lösung L₄ die Anodenkammer K_A entgegen der Schwerkraft verlässt.
   Diese Ausführungsform ist dabei besonders vorteilhaft und deshalb bevorzugt, wenn der Ablauf A_KM durch den Boden der Mittelkammer K_M, und der Zulauf Z_KA durch den Boden der Anodenkammer K_A, ausgebildet wird. Durch diese Anordnung ist es besonders einfach möglich, in der Anodenkammer K_A gebildete Gase mit L₄ aus der Anodenkammer K_A abzuleiten, um diese dann weiter abzutrennen.
   Wenn die Verbindung V_AM außerhalb der Elektrolysezelle E ausgebildet ist, sind insbesondere Z_KM und A_KM an gegenüberliegenden Seiten der Außenwand W_A der Mittelkammer K_M angeordnet (also z.B. Z_KM am Boden und A_KM an der Oberseite O_EM der Elektrolysezelle E oder umgekehrt) und Z_KA und A_KA an gegenüberliegenden Seiten der Außenwand W_A der Anodenkammer K_A angeordnet (also Z_KA am Boden und A_KA an der Oberseite O_EA der Elektrolysezelle E), wie es insbesondere in Abbildungen 2 A, 2 B und 5 gezeigt ist. Durch diese Geometrie muss L₃ die beiden Kammern K_M und K_A durchströmen. Dabei können Z_KA und Z_KM an derselben Seite der Elektrolysezelle E ausgebildet sein, wobei dann automatisch auch A_KM und A_KA an derselben Seite der Elektrolysezelle E ausgebildet sind. Alternativ können Z_KA und Z_KM an gegenüberliegenden Seiten der Elektrolysezelle E ausgebildet sein, wobei dann automatisch auch A_KM und A_KA an gegenüberliegenden Seiten der Elektrolysezelle E ausgebildet sind.
3. 3) Wenn die Verbindung V_AM innerhalb der Elektrolysezelle E ausgebildet ist, kann dies insbesondere dadurch gewährleistet werden, dass eine Seite ("Seite A") der Elektrolysezelle E, bei der es sich um die Oberseite O_E handelt, den Zulauf Z_KM und den Ablauf A_KA umfasst und die Diffusionsbarriere D ausgehend von dieser Seite ("Seite A") sich in die Elektrolysezelle E erstreckt, aber nicht ganz bis zur der der Seite A gegenüberliegenden Seite ("Seite B") der Elektrolysezelle E, bei der es dann sich um den Boden der Elektrolysezelle E handelt, reicht und dabei 50 % oder mehr der Höhe der Dreikammerzelle E, bevorzugter 60 % bis 99 % der Höhe der Dreikammerzelle E, noch bevorzugter 70 % bis 95 % der Höhe der Dreikammerzelle E, noch mehr bevorzugter 80 % bis 90 % der Höhe der Dreikammerzelle E, noch viel mehr bevorzugter 85 % der Höhe der Dreikammerzelle E durchspannt. Dadurch dass die Diffusionsbarriere D die Seite B der Dreikammerzelle E nicht berührt, entsteht so ein Spalt zwischen Diffusionsbarriere D und dem Behältnis B_E auf Seite B der Dreikammerzelle E. Der Spalt ist dann die Verbindung V_AM. Durch diese Geometrie muss L₃ die beiden Kammern K_M und K_A vollständig durchströmen.

In the electrolytic cell E , the outlet A _KM is connected to the inlet Z _KA by a connection V _AM in such a way that liquid can be conducted from I _KM into I _KA through the connection V _AM ,
The connection V _AM can be formed inside the electrolytic cell E and/or outside the electrolytic cell E , and is preferably formed inside the electrolytic cell.

1. 1) If the connection V _AM is formed within the electrolytic cell E , it is preferably formed by at least one perforation in the diffusion barrier D. This embodiment is particularly preferred when a non-ion-specific dividing wall, in particular a metal fabric or textile fabric, is used as the diffusion barrier D. This works as a diffusion barrier D and, due to the weaving properties, has perforations and gaps from the outset, which act as a connection V _AM .
2. 2) The embodiment described below is particularly preferred when a membrane permeable to specific ions is used as the diffusion barrier D : In this embodiment, the connection V _AM is formed outside the electrolytic cell E , and it is preferably formed by a connection running outside of the electrolytic cell E A _KM and Z _KA is formed, in particular in that an outlet A _KM is formed from the interior of the middle chamber I _KM , preferably at the bottom of the middle chamber K _M , with the inlet Z _KM even more preferably being at the top O _EM of the middle chamber K _M and an inlet Z _KA into the interior I _KA of the anode chamber K _A , preferably at the bottom of the anode chamber K _A , is formed, and this through a line, for example a pipe or hose, which is preferably a material selected from rubber, plastic includes, are connected. This is particularly advantageous because the outlet A _KA is formed according to the invention on the upper side O _EA of the anode chamber K _A .
   "Outflow A _KM at the bottom of the middle chamber K _M " means in particular that the outflow A _KM is attached to the electrolytic cell E in such a way that the solution L ₃ leaves the middle chamber K _M in the same direction as gravity.
   "Inlet Z _KA at the bottom of the anode chamber K _A " means in particular that the inlet Z _KA is attached to the electrolytic cell E in such a way that the solution L ₃ enters the anode chamber K _A counter to the force of gravity.
   "Feed Z _KM at the top O _EM of the central chamber K _M " means in particular that the feed Z _KM is attached to the electrolytic cell E such that the solution L ₃ enters the central chamber K _M in the same direction as gravity.
   "Outflow A _KA on the top O _EA of the anode chamber K _A " means in particular that the outflow A _KA is attached to the electrolytic cell E in such a way that the solution L ₄ leaves the anode chamber K _A against the force of gravity.
   This embodiment is particularly advantageous and therefore preferred if the outlet A _KM is formed through the base of the central chamber K _M and the inlet Z _KA is formed through the base of the anode chamber K _A . This arrangement makes it particularly easy to discharge gases formed in the anode chamber K _A with L ₄ from the anode chamber K _A in order to then separate them further.
   If the connection V _AM is formed outside the electrolytic cell E , in particular Z _KM and A _KM are arranged on opposite sides of the outer wall W _A of the central chamber K _M (i.e. Z _KM on the bottom and A _KM on the top O _EM of the electrolytic cell E or vice versa) and Z _KA and A _KA are arranged on opposite sides of the outer wall W _A of the anode chamber K _A (i.e. Z _KA at the bottom and A _KA at the top O _EA of the electrolytic cell E ), as shown in particular in Figures 2A, 2B and 5. Due to this geometry , L ₃ must flow through the two chambers K _M and K _A . In this case, Z _KA and Z _KM can be formed on the same side of the electrolytic cell E , with A _KM and A _KA then automatically also being formed on the same side of the electrolytic cell E. Alternatively, Z _KA and Z _KM can be formed on opposite sides of the electrolytic cell E , with A _KM and A _KA then automatically also being formed on opposite sides of the electrolytic cell E.
3. 3) If the connection V _AM is formed inside the electrolytic cell E , this can be ensured in particular by having one side ("side A") of the electrolytic cell E, which is the top O _E , the inlet Z _KM and comprises the outlet A _KA and the diffusion barrier D extends from this side ("side A") into the electrolytic cell E , but not all the way to the side A opposite ("side B") of the electrolytic cell E, where it then it is the bottom of the electrolytic cell E , and it is 50% or more of the height of the three-chamber cell E, more preferably 60% to 99% of the height of the three-chamber cell E, even more preferably 70% to 95% of the height of the three-chamber cell E, even more preferably 80% to 90% of the height of the three-chamber cell E, even more preferably 85% of the height of the three-chamber cell E spans. The fact that the diffusion barrier D does not touch side B of the three-chamber cell E creates a gap between the diffusion barrier D and the container B _E on side B of the three-chamber cell E. The gap is then the connection V _AM . Due to this geometry , L ₃ must flow completely through the two chambers K _M and K _A .

These embodiments best ensure that the aqueous salt solution L ₃ flows past the acid-sensitive solid electrolyte before it comes into contact with the anodic electrode _EA , as a result of which acids are formed.

"Bottom of the electrolytic cell E" is, according to the invention , the side of the electrolytic cell E through which a solution (e.g. L ₃ at A _KM in Figure 2A) in the same direction as gravity exits the electrolytic cell E or the side of the electrolytic cell E through which a solution (e.g. L ₂ at Z _KK in Figures 1 A, 2 A and 3 A and L ₃ at A _KA in Figures 1 A and 2 A) is fed to the electrolytic cell E against the force of gravity.

According to the invention, "top O _E of the electrolytic cell E" is the side of the electrolytic cell E through which a solution (e.g. L ₄ at A _KA and L ₁ at A _KK in all figures) escapes from the electrolytic cell E against the force of gravity or the side of the Electrolytic cell E, through which a solution (eg L ₃ at Z _KM in Figures 2 A, 2 B, 3 A, 3 B and 4) is fed to the electrolytic cell E in the same direction as gravity.

4.1.4 Arrangement of the partition wall W in the electrolytic cell E

The dividing wall W is arranged in the electrolytic cell E in such a way that the solid electrolyte ceramics, which conduct alkali cations and are enclosed by the dividing wall W , make direct contact with the interior space I _KK on the side S _KK .

This means that the partition W is arranged in the electrolytic cell E in such a way that when the interior space I _KK is completely filled with solution L ₄ on the side S _KK , the solution L ₄ contacts all of the solid electrolyte ceramics contained in the partition W that conduct alkali cations , so that ions (eg alkali metal ions such as sodium, lithium) from all solid electrolyte ceramics which conduct alkali cations and are encompassed by the partition W can enter the solution L ₄ .

In addition, the dividing wall W is arranged in the embodiments in which the electrolytic cell E does not include a middle chamber K _M in the electrolytic cell E such that the solid electrolyte ceramics enclosing the dividing wall W make direct contact with the interior space I _KA .

This means the following: in the embodiments in which the electrolytic cell E does not include a central chamber K _M , the partition wall W borders on the interior space I _KA of the anode chamber K _A . In these embodiments, the dividing wall W is arranged in the electrolytic cell E in such a way that when the interior space I _KA is completely filled with solution L ₃ , the solution L ₃ then contacts all of the solid electrolyte ceramics that conduct alkali cations that are contained in the dividing wall W , so that ions ( For example, alkali metal ions such as sodium, lithium) from the solution L ₃ in any alkali cation-conducting solid electrolyte ceramic, which is comprised of the partition W , can occur.

In addition, the dividing wall W is arranged in the electrolytic cell E in cases in which the electrolytic cell E comprises at least one central chamber K _M such that the solid electrolyte ceramics which are comprised of the dividing wall W and which conduct alkali cations make direct contact with the interior space I _KM .

This means the following: in the embodiments in which the electrolytic cell E comprises at least one central chamber K _M , the partition wall W borders on the interior space I _KM of the central chamber K _M . In these embodiments, the dividing wall W is arranged in the electrolytic cell E in such a way that when the interior space I _KM is completely filled with solution L ₃ , the solution L ₃ then contacts all of the solid electrolyte ceramics that conduct alkali cations that are contained in the dividing wall W , so that ions (eg alkali metal ions such as sodium, lithium) from the solution L ₃ can enter any alkali cation-conducting solid electrolyte ceramic, which is comprised of the partition W.

4.2 Process steps according to the invention

The present invention relates to a process for preparing a solution L ₁ of an alkali metal alkoxide XOR in the alcohol ROH, where X is an alkali metal cation and R is an alkyl radical having 1 to 4 carbon atoms. The process is carried out in an electrolytic cell E.

Preferably X is selected from the group consisting of Li ⁺ , K ⁺ , Na ⁺ , more preferably from the group consisting of K ⁺ , Na ⁺ . Most preferably X = Na ⁺ .

R is preferably selected from the group consisting of n -propyl, iso -propyl, ethyl, methyl, more preferably selected from the group consisting of ethyl, methyl. Most preferably R is methyl.

4.2.1 Process steps in an electrolytic cell E without a central chamber KM

In the cases in which the electrolytic cell E does not include a middle chamber K _M , the steps (α1), (α2), (α3) running simultaneously are carried out.

4.2.1.1 Step (α1)

In step (a1), a solution L ₂ comprising the alcohol ROH, preferably comprising an alkali metal alkoxide XOR and alcohol ROH, is passed through I _KK .

The solution L ₂ is preferably free of water. According to the invention, “free of water” means that the weight of the water in the solution L ₂ based on the weight of the alcohol ROH in the solution L ₂ (mass ratio) is ≦1:10, more preferably ≦1:20, even more preferably ≦1:100 , more preferably ≤ 0.5:100.

If the solution L ₂ comprises XOR, the mass fraction of XOR in the solution L ₂ , based on the entire solution L ₂ , is in particular >0 to 30% by weight, preferably 5 to 20% by weight, even more preferably at 10 to 20% by weight, more preferably at 10 to 15% by weight, most preferably at 13 to 14% by weight, most preferably at 13% by weight.

If the solution L ₂ includes XOR, the mass ratio of XOR to alcohol ROH in the solution L ₂ is in particular in the range from 1:100 to 1:5, more preferably in the range from 1:25 to 3:20, even more preferably in the range 1:12 to 1:8, more preferably at 1:10.

4.2.1.2 Step (α2)

In step (a2), a neutral or alkaline, aqueous solution L ₃ of a salt S comprising X as a cation is passed through I _KA .

The salt S is preferably a halide, sulfate, sulfite, nitrate, bicarbonate or carbonate of X, more preferably a halide.

Halides are fluorides, chlorides, bromides, iodides. The most preferred halide is chloride.

The pH of the aqueous solution L ₃ is ≧7.0, preferably in the range from 7 to 12, more preferably in the range from 8 to 11, even more preferably from 10 to 11, most preferably at 10.5.

The mass fraction of the salt S in the solution L ₃ is preferably in the range > 0 to 20% by weight, preferably 1 to 20% by weight, more preferably 5 to 20% by weight, even more preferably 10 to 20% by weight %, most preferably at 20% by weight, based on the total solution L ₃ .

4.2.1.3 Step (α3)

In step (a3), a voltage is then applied between E _A and E _K .

This leads to a current transport from the charge source to the anode, to a charge transport via ions to the cathode and finally to a current transport back to the charge source. The charge source is known to those skilled in the art and is typically a rectifier that converts alternating current into direct current and can generate specific voltages via voltage converters.

• am Ablauf A_KK wird die Lösung L₁ erhalten, wobei die Konzentration von XOR in L₁ höher ist als in L₂,
• am Ablauf A_KA wird eine wässrige Lösung L₄ von S erhalten, wobei die Konzentration von S in L₄ geringer ist als in L₃ .

This in turn has the following consequences:

• at the outlet A _KK the solution L ₁ is obtained, the concentration of XOR in L ₁ being higher than in L ₂ ,
• at the outlet A _KA an aqueous solution L ₄ of S is obtained, the concentration of S in L ₄ being lower than in L ₃ .

In step (a3) of the method, such a voltage is applied in particular that such a current flows that the current density (= ratio of the current that flows to the electrolytic cell to the area of the solid electrolyte that contacts the anolyte in the interior I _KA ) is in the range of 10 to 8000 A/m ² , more preferably in the range of 100 to 2000 A/m ² , even more preferably in the range of 300 to 800 A/m ² , even more preferably 494 A/m ² . This can be determined by a person skilled in the art by default. The area of the solid electrolyte that contacts the anolyte in the interior I _KA is in particular 0.00001 to 10 m ² , preferably 0.0001 to 2.5 m ² , more preferably 0.0002 to 0.15 m ² , even more preferably 2.83 cm ² .

It goes without saying that step (a3) of the method is carried out when the interior space I _KA is at least partially loaded with L ₃ and the interior space I _KK is at least partially loaded with L ₂ , so that both L ₃ and L ₂ contact the solid electrolyte ceramics, which are conductive to alkali cations and are enclosed by the partition W.

The fact that charge transport takes place between E _A and E _K in step (a3) implies that I _KK and I _KA are simultaneously charged with L ₂ and L ₃ , respectively, in such a way that they cover the electrodes E _A and E _K to such an extent that the circuit is closed.

This is particularly the case when a liquid flow is continuously passed from L ₃ through I _KA and a liquid flow from L ₂ through I _KK and the liquid flow from L ₃ passes the electrode E _A and the liquid flow from L ₂ passes the electrode E _K at least partially , preferably completely covered.

In a further preferred embodiment, the process is carried out continuously, ie step (a1) and step (a2) are carried out continuously and voltage is applied in accordance with step (a3).

After step (a3) has been carried out, the solution L ₁ is obtained at the outlet A _KK , the concentration of XOR in L ₁ being higher than in L ₂ . If L ₂ already comprised XOR, the concentration of XOR in L ₁ is preferably 1.01 to 2.2 fold, more preferably 1.04 to 1.8 fold, even more preferably 1077 to 1.4 fold, even more preferably 1077 to 1077 fold 1.08-fold higher than in L ₂ , most preferably 1,077-fold higher than in L ₂ , more preferably with the mass fraction of XOR in L ₁ and in L ₂ being in the range 10 to 20% by weight, even more preferably 13 to 14% by weight.

At outlet A _KA an aqueous solution L ₄ of S is obtained, the concentration of S in L ₄ being lower than in L3.

The concentration of the cation X in the aqueous solution L ₃ is preferably in the range from 3.5 to 5 mol/l, more preferably 4 mol/l. The concentration of the cation X in the aqueous solution L ₄ is more preferably 0.5 mol/l lower than that of the aqueous solution L ₃ used in each case.

In particular, steps (a1) to (a3) of the process are carried out at a temperature of 20°C to 70°C, preferably 35°C to 65°C, more preferably 35°C to 60°C, even more preferably 35°C to 50 °C and a pressure of 0.5 bar to 1.5 bar, preferably 0.9 bar to 1.1 bar, more preferably 1.0 bar.

When carrying out steps (a1) to (a3) of the method, hydrogen is typically formed in the interior I _KK of the cathode chamber K _K and is discharged from the cell via the outlet A _KK can be discharged together with the solution L ₁ . In a particular embodiment of the present invention, the mixture of hydrogen and solution L ₁ can then be separated by methods known to those skilled in the art. In the interior I _KA of the anode chamber K _A , if the alkali metal compound used is a halide, in particular chloride, chlorine or another halogen gas can form, which can be removed from the cell via the outlet A _KK together with the solution L ₄ . In addition, oxygen and/or carbon dioxide can also be formed, which can also be removed. In a particular embodiment of the present invention, the mixture of chlorine, oxygen and/or CO ₂ and solution L ₄ can then be separated by methods known to those skilled in the art. Likewise, after the gases chlorine, oxygen and/or CO ₂ have been separated from the solution L ₄ , these can be separated from one another by methods known to those skilled in the art.

4.2.2 Process steps in an electrolytic cell E with a central chamber KM

In cases in which the electrolytic cell E comprises at least one central chamber K _M , steps (β1), (β2), (β3) are carried out simultaneously.

It is preferred that the electrolytic cell E comprises at least one middle chamber K _M , and then the steps (β1), (β2), (β3) running simultaneously are carried out.

4.2.2.1 Step (β1)

In step (β1), a solution L ₂ comprising the alcohol ROH, preferably comprising an alkali metal alkoxide XOR and alcohol ROH, is passed through I _KK .

The solution L ₂ is preferably free of water. According to the invention, “free of water” means that the weight of the water in the solution L ₂ based on the weight of the alcohol ROH in the solution L ₂ (mass ratio) is ≦1:10, more preferably ≦1:20, even more preferably ≦1:100 , more preferably ≤ 0.5:100.

If the solution L ₂ comprises XOR, the mass fraction of XOR in the solution L ₂ , based on the entire solution L ₂ , is in particular >0 to 30% by weight, preferably 5 to 20% by weight, even more preferably at 10 to 20% by weight, more preferably at 10 to 15% by weight, most preferably at 13 to 14% by weight, most preferably at 13% by weight.

If the solution L ₂ includes XOR, the mass ratio of XOR to alcohol ROH in the solution L ₂ is in particular in the range from 1:100 to 1:5, more preferably in the range from 1:25 to 3:20, even more preferably in the range 1:12 to 1:8, more preferably at 1:10.

4.2.2.2 Step (β2)

In step (β2), a neutral or alkaline aqueous solution L ₃ of a salt S comprising X as a cation is passed through I _KM , then over V _AM , then through I _KA .

The salt S is preferably a halide, sulfate, sulfite, nitrate, bicarbonate or carbonate of X, more preferably a halide.

Halides are fluorides, chlorides, bromides, iodides. The most preferred halide is chloride.

The pH of the aqueous solution L ₃ is ≧7.0, preferably in the range from 7 to 12, more preferably in the range from 8 to 11, even more preferably from 10 to 11, most preferably at 10.5.

The mass fraction of the salt S in the solution L ₃ is preferably in the range > 0 to 20% by weight, preferably 1 to 20% by weight, more preferably 5 to 20% by weight, even more preferably 10 to 20% by weight %, most preferably at 20% by weight, based on the total solution L ₃ .

4.2.2.3 Step (β3)

In step (β3), a voltage is then applied between E _A and E _K .

This leads to a current transport from the charge source to the anode, to a charge transport via ions to the cathode and finally to a current transport back to the charge source. The charge source is known to those skilled in the art and is typically a rectifier that converts alternating current into direct current and can generate certain voltages via voltage converters.

• am Ablauf A_KK wird die Lösung L₁ erhalten, wobei die Konzentration von XOR in L₁ höher ist als in L₂,
• am Ablauf A_KA wird eine wässrige Lösung L₄ von S erhalten, wobei die Konzentration von S in L₄ geringer ist als in L ₃.

This in turn has the following consequences:

• at the outlet A _KK the solution L ₁ is obtained, the concentration of XOR in L ₁ being higher than in L ₂ ,
• at the outlet A _KA an aqueous solution L ₄ of S is obtained, the concentration of S in L ₄ being lower than in L ₃ .

In step (β3) of the method, such a voltage is applied in particular that a current flows such that the current density (= ratio of the current flowing to the electrolytic cell to the area of the solid electrolyte that contacts the anolyte I _KM located in the interior) is in the range of 10 to 8000 A/m ² , more preferably in the range of 100 to 2000 A/m ² , even more preferably in the range of 300 to 800 A/m ² , even more preferably 494 A/m ² . This can be determined by a person skilled in the art by default. The area of the solid electrolyte that contacts the anolyte located in the interior I _KM of the middle chamber K _M is in particular 0.00001 to 10 m ² , preferably 0.0001 to 2.5 m ² , more preferably 0.0002 to 0.15 m ² , still more preferably 2.83 cm ² .

It goes without saying that step (β3) of the method is carried out when both interior spaces I _KM and I _KA are at least partially loaded with L ₃ and I _KK is at least partially loaded with L ₂ , so that both L ₃ and L ₂ also contact the solid electrolytes enclosed by the partition W.

The fact that charge transport takes place between E _A and E _K in step (β3) implies that I _KK , I _KM and I _KA are simultaneously charged with L ₂ and L ₃ , respectively, in such a way that they connect the electrodes E _A and E _K so far that the circuit is closed.

This is particularly the case when a liquid stream is continuously passed from L ₃ through I _KM , V _AM and I _KA and a liquid stream from L ₂ through I _KK and the liquid stream from L ₃ passes the electrode E _A and the liquid stream from L ₂ the electrode E _K at least partially, preferably completely covered.

In a further preferred embodiment, the process is carried out continuously, ie step (β1) and step (β2) are carried out continuously and voltage is applied in accordance with step (β3).

After step (β3) has been carried out, the solution L ₁ is obtained at the outlet A _KK , the concentration of XOR in L ₁ being higher than in L ₂ . If L ₂ already comprised XOR, the concentration of XOR in L ₁ is preferably 1.01 to 2.2 fold, more preferably 1.04 to 1.8 fold, even more preferably 1077 to 1.4 fold, even more preferably 1077 to 1077 fold 1.08-fold higher than in L ₂ , most preferably 1,077-fold higher than in L ₂ , more preferably with the mass fraction of XOR in L ₁ and in L ₂ being in the range 10 to 20% by weight, even more preferably 13 to 14% by weight.

At outlet A _KA an aqueous solution L ₄ of S is obtained, the concentration of S in L ₄ being lower than in L ₃ .

The concentration of the cation X in the aqueous solution L ₃ is preferably in the range from 3.5 to 5 mol/l, more preferably 4 mol/l. The concentration of the cation X in the aqueous solution L ₄ is more preferably 0.5 mol/l lower than that of the aqueous solution L ₃ used in each case.

In particular, steps (β1) to (β3) of the process are carried out at a temperature of 20°C to 70°C, preferably 35°C to 65°C, more preferably 35°C to 60°C, even more preferably 35°C to 50 °C and a pressure of 0.5 bar to 1.5 bar, preferably 0.9 bar to 1.1 bar, more preferably 1.0 bar.

When carrying out steps (β1) to (β3) of the method, hydrogen is typically produced in the interior I _KK of the cathode chamber K _K , which hydrogen can be discharged from the cell together with the solution L ₁ via the outlet A _KK . In a particular embodiment of the present invention, the mixture of hydrogen and solution L ₁ can then be separated by methods known to those skilled in the art. In the interior I _KA of the anode chamber K _A , if the alkali metal compound used is a halide, in particular chloride, chlorine or another halogen gas can form, which can be removed from the cell via the outlet A _KK together with the solution L ₄ . In addition, oxygen and/or carbon dioxide can also be formed, which can also be removed. In a particular embodiment of the present invention, the mixture of chlorine, oxygen and/or CO ₂ and solution L ₄ can then be separated by methods known to those skilled in the art. Likewise, after the gases chlorine, oxygen and/or CO ₂ have been separated from the solution L ₄ , these can be separated from one another by methods known to those skilled in the art.

4.2.2.4 Additional advantages of steps (β1) to (β3)

Carrying out steps (β1) to (β3) brings other surprising advantages which were not to be expected in the light of the prior art. Steps (β1) to (β3) of the method according to the invention protect the acid-labile solid electrolyte from corrosion without having to sacrifice alcoholate solution from the cathode space as a buffer solution, as in the prior art. These process steps are therefore more efficient than those in WO 2008/076327 A1 described procedure in which the product solution is used for the middle chamber, which reduces the overall turnover.

4.3 Characteristic feature of the method according to the invention

The method according to the invention is characterized in that at least one, preferably both, of the following conditions (i), (ii) is/are fulfilled. In a preferred embodiment, condition (iii) described below is also met in cases in which the electrolytic cell E comprises at least one central chamber K _M and the connection V _AM is formed outside the electrolytic cell E.

4.3.1 Condition (i)

1. (i) O _EA is essentially formed as a plane whose normal N _OEA forms an angle φ _PEA , where 0° < φ _EA < 45°, to the gravity vector V _S , and the drain A _KA is on the top half of O _EA arranged.

It is preferably 0.5°≦ϕ _EA ≦30°, more preferably 1°≦ϕ _EA ≦26°, more preferably 1°≦ϕ _EA ≦12°, more preferably 1°≦ϕ _EA ≦11°, more preferably 1°≦ϕ _EA ≦10 °, more preferred 1° ≤ ϕ _EA ≤ 9°, more preferred 1° ≤ ϕ _EA ≤ 8°, more preferred 1° ≤ ϕ _EA ≤ 7°, more preferred 1° ≤ ϕ _EA ≤ 6°, more preferred 1° ≤ ϕ _EA ≤ 5 °, more preferably 1° ≤ φ _EA ≤ 4°, more preferably 1° ≤ φ _EA ≤ 3°, more preferably 1° ≤ φ _EA ≤ 2°.

“Normal N _OEA ” in the sense of the invention refers to the normal line (ie orthogonal straight line) or else the normal vector (ie orthogonal vector) to the upper side O _EA , which is essentially designed as a plane.

The normal N _OEA is therefore the vector or straight line which is perpendicular to the plane formed by the upper side O _EA . This vector intersects the vector of gravity at the angle ϕ _EA .

Accordingly, the angle φ _EA can be determined by intersecting the straight line that is perpendicular to the plane formed by the upper side O _EA with a straight line that is parallel to the direction of gravity.

If these two straight lines or these two vectors intersect at an angle that is greater than 0° and less than 45°, then the condition is that "the normal N _OEA forms an angle ϕ _EA to the gravity vector V _s , where 0° < ϕ _EA <45°".

The flow A _KA is located on the upper half of O _EA . This means the following: Due to the inclination of the upper surface O _EA with respect to the gravity vector V _s and the fact that O _EA is essentially formed as a plane, one half of the upper surface O _EA is higher than the other half of the upper surface O _EA . A _KA is attached to this upper half. In the preferred embodiments where A _KA is located on the top n _KA th of O _EA , where n _KA = 3, 4, 5 or 10, this means that A _KA is located on the top n _KA th of each is arranged by O _EA .

Because its normal N _OEA forms an angle of 0° < ϕ _EA < 45° to the gravitational vector V _s , the upper side O _EA is inclined in relation to this, which means that the gases produced in the interior I _KA are at the highest point of the interior due to the difference in density from the electrolyte I _KA rise. This rising of the gases is facilitated by the fact that the upper side O _EA is designed as a plane, in particular it does not have any steps or spikes in which gas bubbles could get caught. Due to the fact that the outlet A _KA is arranged on the upper half of O _EA , at least some of the gases pass through the outlet A _KA when ascending to the highest point and are thus discharged from the interior I _KA , whereby the interior I _KA completely through the Electrolyte L ₃ can be filled. This increases the efficiency of the electrolysis. In particular, according to condition (i), O _EA is formed as a plane whose normal N _OEA forms an angle ϕ _EA , where 0° < ϕ _EA < 45°, to the gravity vector V _s , and the sequence A _KA is on the upper half of O _EA arranged.

4.3.2 Condition (ii)

(ii) O _EK is essentially a plane whose normal N _OEK forms an angle φ _EK , where 0° < φ _EK < 45°, to the gravity vector V _s , and the drain A _KK is on the top half of O _EK arranged.

It is preferably 0.5°≦ϕ _EK ≦30°, more preferably 1°≦ϕ _EK ≦26°, more preferably 1°≦ϕ _EK ≦12°, more preferably 1°≦ϕ _EK ≦11°, more preferably 1°≦ϕ _EK ≦10 °, more preferred 1° ≤ ϕ _EK ≤ 9°, more preferred 1° ≤ ϕ _EK ≤ 8°, more preferred 1° ≤ ϕ _EK ≤ 7°, more preferred 1° ≤ ϕ _EK ≤ 6°, more preferred 1° ≤ ϕ _EK ≤ 5 °, more preferably 1° ≤ φ _EK ≤ 4°, more preferably 1° ≤ φ _EK ≤ 3°, more preferably 1° ≤ φ _EK ≤ 2°.

“Normal N _OEK ” in the sense of the invention refers to the normal straight line (ie orthogonal straight line) or also the normal vector (ie orthogonal vector) to the upper side O _EK , which is essentially designed as a plane.

The normal N _OEK is accordingly the vector or the straight line which is perpendicular to the plane which is formed by the upper side O _EK . This vector intersects the vector of gravity at the angle ϕ _EK .

Accordingly, the angle φ _EK can be determined by intersecting the straight line that is perpendicular to the plane formed by the upper side O _EK with a straight line that is parallel to the direction of gravity.

If these two straight lines or these two vectors intersect at an angle that is greater than 0° and less than 45°, then the condition is that "the normal N _OEK forms an angle ϕ _EK to the gravity vector V _s , with 0° < ϕ _EK <45°".

The sequence A _KK is arranged on the upper half of O _EK . This means the following: due to the inclination of the upper side O _EK with respect to the gravitational vector V _s and due to the fact that O _EK is formed essentially as a plane, one half of the upper side O _EK is higher than the other half of the upper side O _EK . A _KK is attached to this upper half. In the preferred embodiments where A _KK is located on the top nKK th of O _EK , where nKK = 3, 4, 5 or 10, this means that it is located on the top n _KK th part of O _EK is.

The upper side O _EK is because its normal N _OEK forms an angle 0°<ϕ _EK <45° to the gravitational vector V _s , inclined in relation to this, whereby gases arising in the interior I _KK due to the density difference to the electrolyte reach the highest point of the interior I _KK rise. This rising of the gases is facilitated by the fact that the upper side O _EK is in the form of a plane, in particular it does not have any steps or spikes in which gas bubbles could get caught. Due to the fact that the outlet A _KK is arranged on the upper half of O _EK , at least some of the gases pass through the outlet A _KK when ascending to the highest point and are thus discharged from the interior I _KK , whereby the interior I _KK completely through the Electrolyte L ₂ can be filled. This increases the efficiency of the electrolysis.

In particular, according to condition (ii), O _EK is formed as a plane whose normal N _OEK forms an angle ϕ _EK , where 0° < ϕ _EK < 45°, to the gravity vector V _s , and the sequence A _KK is on the upper half of O _EK arranged.

4.3.3 Condition (i) and (ii) met

In a further preferred embodiment of the process according to the invention, both conditions (i) and (ii) are met. Then, even more preferably, φ _EK and φ _EA are equal. Even more preferably, the following then applies to both:
0.5° ≤ ϕ _EK = ϕ _EA ≤ 30°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 26°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 12°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 11° , more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 10°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 9°, more preferably 1 ° ≤ ϕ _EK = ϕ _EA ≤ 8°, more preferably 1 ° ≤ ϕ _EK = ϕ _EA ≤ 7°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 6°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 5°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 4°, more preferably 1° ≤ ϕ _EK = ϕ _EA ≤ 3°, more preferably 1° ≤ φ _EK = φ _EA ≤ 2°.

More preferably then drain A _KA is located on the top half of O _EA and drain A _KK is located on the top half of O _EK , more preferably then drain A _KA is located on the top third of O _EA and drain A _KK on the top third of O _EK , more preferably then drain A _KA is located on the top quarter of O _EA and drain A _KK is located on the top quarter of O _EK , more preferably then drain A _KA is located on the top fifth of O _EA and Flow A _KK is located on the top fifth of O _EK , more preferably then flow A _KA is located on the top tenth of O _EA and flow A _KK is located on the top tenth of O _EK .

The combination of the two conditions (i) and (ii) prevents the formation of a gas cushion in the respective interior space I _KK and I _KA of the cathode chamber K _K and anode chamber K _A in a particularly efficient manner.

4.3.2 Optional condition (iii)

In a preferred embodiment of the cases in which the electrolytic cell E has a central chamber K _M and the connection V _AM is formed outside the electrolytic cell E , the following applies:
(iii) O _EM is essentially a plane whose normal N _OEM forms an angle φ _EM , where 0° < φ _EM < 45°, to the gravity vector V _s , and the gradient A _KM is on the top half of O _EM arranged.

It is preferably 0.5°≦ϕ _EM ≦30°, more preferably 1°≦ϕ _EM ≦26°, more preferably 1°≦ϕ _EM ≦12°, more preferably 1°≦ϕ _EM ≦11°, more preferably 1°≦ϕ _EM ≦10 °, more preferred 1° ≤ ϕ _EM ≤ 9°, more preferred 1° ≤ ϕ _EM ≤ 8°, more preferred 1° ≤ ϕ _EM ≤ 7°, more preferred 1° ≤ ϕ _EM ≤ 6°, more preferred 1° ≤ ϕ _EM ≤ 5 °, more preferably 1° ≤ φ _EM ≤ 4°, more preferably 1° ≤ φ _EM ≤ 3°, more preferably 1° ≤ φ _EM ≤ 2°.

“Normal N _OEM ” in the sense of the invention refers to the normal line (ie orthogonal straight line) or also the normal vector (ie orthogonal vector) to the upper side O _EM , which is essentially designed as a plane.

The normal N _OEM is the vector or line perpendicular to the plane formed by the top O _EM . This vector intersects the vector of gravity at the angle ϕ _EM .

In the same way, the angle φ _EM can be determined by intersecting the straight line that is perpendicular to the plane formed by the upper side O _EM with a straight line that is parallel to the direction of gravity.

If these two straight lines or these two vectors intersect at an angle that is greater than 0° and less than 45°, then the condition is that "the normal N _OEM forms an angle ϕ _EM to the gravitational vector V _s , with 0° < ϕ _EM <45°".

The sequence A _KM is arranged on the upper half of O _EM in this preferred embodiment. This means the following: Due to the inclination of the upper surface O _EM with respect to the gravity vector V _s and the fact that O _EM is essentially formed as a plane, one half of the upper surface O _EM is higher than the other half of the upper surface O _EM . A _KM is affixed to this upper half. In the preferred embodiments where A _KM is located on the top n _KM -th of O _EM , where n _KM = 3, 4, 5 or 10, this means that it is located on the top n _KM -th part of O _EM is arranged.

In this preferred embodiment, the upper side O _EM is inclined in that its normal N _OEM forms an angle 0°<φ _EK <45° to the gravity vector V _s , which means that the gases produced in the interior I _KM are at the highest due to the density difference Place of interior I _KM rise. This rising of the gases is facilitated by the fact that the upper side O _EM is in the form of a plane, in particular it does not have any steps or spikes in which gas bubbles could get caught. Due to the fact that the outlet A _KM is arranged on the upper half of O _EM , at least some of the gases pass through the outlet A _KM when ascending to the highest point and are thus discharged from the interior I _KM , whereby the interior I _KM completely through the Electrolyte L ₂ can be filled. This increases the efficiency of the electrolysis.

• 0.5° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 30°, bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 26°,
• bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 12°, bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 11°,
• bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 10°, bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 9°,
• bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 8°, bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 7°,
• bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 6°, bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 5°,
• bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 4°, bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 3°,
• bevorzugter 1° ≤ ϕ_EK = ϕ_EA = ϕ_EM ≤ 2°.

In a further preferred embodiment, all of the conditions (i), (ii) and (iii) are met. Then it is even more preferred that ϕ _EK =ϕ _EA =ϕ _EM . Even more preferably, all three are then:

• 0.5° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 30°, more preferably 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 26°,
• more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 12°, more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 11°,
• more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 10°, more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 9°,
• more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 8°, more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 7°,
• more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 6°, more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 5°,
• more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 4°, more preferred 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 3°,
• more preferably 1° ≤ ϕ _EK = ϕ _EA = ϕ _EM ≤ 2°.

In particular, according to optional condition (iii), O _EM is formed as a plane whose normal N _OEM forms an angle φ _EM , where 0° < φ _EM < 45°, to the gravity vector V _s , and the sequence A _KM is on the upper half Arranged by O _EM .

5. Examples 5.1 Comparative example 1

Sodium methylate (NM) was produced via a cathodic process, with 20% by weight NaCl solution (in water) being fed into the anode chamber and 10% by weight methanolic NM solution being fed into the cathode chamber. The electrolytic cell consisted of three chambers, as in Figure 7 shown. The electrolytic cell was not tilted so that the normal to the top of the electrolytic chamber was parallel to the gravity vector. The drains of the anode chamber and the cathode chamber were also found in the center of the top.

The connection between the middle and anode chamber was made by a hose that was attached to the bottom of the electrolytic cell. The anode compartment and middle compartment were separated by a 2.83 cm ² anion exchange membrane (Tokuyama AMX, ammonium groups on polymer). The cathode and middle chamber were separated by a ceramic of the NaSICON type with an area of 2.83 cm ² . The ceramic had a chemical composition of the formula Na _3.4 Zr _2.0 Si _2.4 P _0.6 O ₁₂ .

The anolyte was transferred to the anode compartment through the middle compartment. The flow rate of the anolyte was 1 l/h, that of the catholyte was 90 ml/h and a current of 0.14 A was applied. The temperature was 35°C. The electrolysis was carried out for 500 hours with the voltage remaining constant at 5V.

It was observed that a pH gradient formed in the middle chamber over a longer period of time, which can be attributed to the migration of the ions to the electrodes during the course of the electrolysis and the propagation of the protons formed at the anode in subsequent reactions. This local increase in the pH value is undesirable since it can attack the solid electrolyte and can lead to corrosion and breakage of the solid electrolyte, especially over very long running times.

In addition, with longer operating times, gas cushions form in the interior spaces of the cathode and anode chambers, in particular due to the formation of chlorine gas and hydrogen at the anode or cathode.

This is problematic because the volume occupied by these gases is no longer available for electrolysis and increases resistance. In addition, chlorine should be removed as quickly as possible in order to curb the acidification of the electrolyte. If this becomes acidic, it damages the NaSICON ceramic.

5.2 Comparative example 2

Comparative example 1 was repeated with a two-chamber cell comprising only an anode and a cathode chamber, the anode chamber being separated from the cathode chamber by the ceramic of the NaSICON type. The arrangement corresponded to that in Figure 6 shown. Thus, this electrolytic cell did not contain a center chamber. The electrolytic cell was not tilted so that the normal to the top of the electrolytic chamber was parallel to the gravity vector. The drains of the anode chamber and the cathode chamber were also found in the center of the top.

This is reflected in an even more rapid corrosion of the ceramic compared to comparative example 1, which leads to a rapid rise in the stress curve. With an initial value of the voltage of < 5 V, this increases to > 20 V within 100 hours.

5.3 Example 1 according to the invention

Comparative example 1 is repeated using an electrolytic cell according to Figures 2A and 2B which is tilted. The drains of the anode chamber and the cathode chamber were also found on the top near the highest edge.

With this arrangement, the gases produced in the anode and cathode chambers are quickly discharged from the electrolysis chamber at the outlet. This ensures that the interior volumes are not blocked by gas bubbles. In addition, the acidification process of the electrolytes, especially the anolyte, is curbed.

5.4 Example 2 according to the invention

Comparative example 2 is repeated using an electrolytic cell according to Figures 1A and 1B which is tilted. The drains of the anode chamber and the cathode chamber were also found on the top near the highest edge.

With this arrangement, the gases produced in the anode and cathode chambers are quickly discharged from the electrolysis chamber at the outlet. This ensures that the interior volumes are not blocked by gas bubbles. In addition, the acidification process of the electrolytes, especially the anolyte, is curbed.

5.5 Outcome

The inventive inclination of the upper side of the electrolytic cell in the area of the anode and cathode chambers and the inventive arrangement of the drains prevent the formation of a gas cushion in the respective interior space. As a result, the volumes of the interior spaces are completely available for the electrolytes and thus for the electrolysis, and there are no undesired increases in voltage. Gases (such as chlorine) produced at the respective electrode are quickly discharged, which prevents the electrolyte from acidifying and thus also protects the NaSICON ceramic.

The use of the three-chamber cell in the method of the invention also prevents corrosion of the solid electrolyte while at the same time not sacrificing an alkali metal alkoxide product for the center chamber and keeping the voltage constant. These advantages, which can already be seen from the comparison of the two comparative examples 1 and 2, underline the surprising effect of using the electrolytic cell comprising at least one middle chamber in the process according to the invention.

6. Reference marks in the figures

electrolytic cell E <1> anode chamber K _A <11> Intake Z _KA <110> Sequence A _KA <111> inner space I _KA <112> anodic electrode E _A <113> cathode chamber K _K <12> Intake Z _KK <120> Sequence A _KK <121> inner space I _KK <122> cathodic electrode E _K <123> center chamber K _M <13> Intake Z _KM <130> Sequence _AKM <131> inner space I _KM <132> diffusion barrier D <14> Connection _VAM <15> partition wall W <16> solid electrolyte ceramic F _A <18> container B _E <800> Part of the container B _E that delimits the anode chamber interior I _{KA BEA} <8001> Part of the container B _E that delimits the cathode chamber interior I _KK B _EK <8002> Part of the container B _E that delimits the central chamber interior I _KK B _EM <8003> top O _E <801> Part of the top O _E that delimits the anode chamber interior I _KA Oh _EA <8011> Part of the top O _E that delimits the cathode chamber interior I _KK O _EK <8012> Part of the top O _E that delimits the middle chamber interior I _KK O _EM <8013> Alkali metal alkoxide XOR in alcohol ROH _L1 <21> Solution comprising the alcohol ROH _L2 <22> neutral or alkaline, aqueous solution of a _L3 <23> Salt S comprising X as a cation aqueous solution of S, where [ S ] _L4 < [ S ] _L3 . _L4 <24> perspective in Fig. 1B , 2 B and 3 B , the top view in Fig. 1A , 2 A or. 3 A is equivalent to <30> gravity vector V _S <90> Normal to O _EA NO _OEA <91> Normal to O _EK N _OEK <92> Angle between normal N _OEA and gravity vector V _s ϕ _EA Angle between normal N _OEK and gravity vector V _s ϕ _EK

Claims (15)

Process for preparing a solution L ₁ <21> of an alkali metal alkoxide XOR in the alcohol ROH in an electrolytic cell E <1>, where X is an alkali metal cation and R is an alkyl radical having 1 to 4 carbon atoms, wherein the electrolytic cell E <1> forms a container B _E <800> and a top O _E <801>, wherein the electrolytic cell E <1> comprises at least one anode chamber K _A <11>, at least one cathode chamber K _K <12> and optionally at least one intermediate chamber K _M <13>, wherein the at least one anode chamber K _A <11> - at least one inlet Z _KA <110>, - at least one sequence A _KA <111> - and an interior space I _KA <112> comprising an anodic electrode E _A <113> and formed by a part O _EA <8011> of the top O _E <801> and a part B _EA <8001> of the container B _E <800 > is limited includes, wherein the at least one cathode chamber K _K <12> - at least one inlet Z _KK <120>, - at least one sequence A _KK <121> - and an interior space I _KK <122> comprising a cathodic electrode E _K <123> and by a part O _EK <8012> of the top O _E <801> and a part B _EK <8002> of the container B _E <800 > is limited includes, and where the electrolytic cell E <1> comprises at least one central chamber K _M <13>, the central chamber K _M <13> - at least one inlet Z _KM <130>, - at least one sequence A _KM <131> - and an interior I _KM <132>, which is delimited by a part O _EM <8013> of the upper side O _E <801> and a part B _EM <8003> of the container B _E <800>, includes, and in which case I _KA <112> and I _KM <132> are separated from one another by a diffusion barrier D <14>, and A _KM <131> by a connection V _AM <15> with the inlet Z _KA <110> is connected so that liquid can be conducted from I _KM <132> to I _KA <112> through the connection V _AM <15>, whereby in cases where the electrolytic cell E <1> does not include a middle chamber K _M <13>, I _KA <112> and I _KK <122> separated by a partition W <16> comprising at least one alkali cation-conducting solid electrolyte ceramic F _A <18> are separated, with the alkali cation-conducting solid electrolyte ceramics enclosed by the partition W <16> directly contacting the interior space I _KK <122> and the interior space I _KA <112>, in cases where the electrolytic cell E <1> comprises at least one middle chamber K _M <13>, I _KK <122> and I _KM <132> through a partition wall W <16> comprising at least one alkali cation-conducting solid electrolyte ceramic F _A <18> are separated from one another, with the alkali cation-conducting solid electrolyte ceramics enclosed by the partition W <16> directly contacting the interior space I _KK <122> and the interior space I _KM <132>, (α) where, in the cases in which the electrolytic cell E <1> does not include a central chamber K _M <13>, the following steps (α1), (α2), (α3) are carried out simultaneously: (α1) a solution L ₂ <22> comprising the alcohol ROH is passed through I _KK <122>, (α2) a neutral or alkaline, aqueous solution L ₃ <23> of a salt S comprising X as a cation is passed through I _KA <112>, (α3) voltage is applied between E _A <113> and E _K <123>, or (β) where, in the cases in which the electrolytic cell E <1> comprises at least one central chamber K _M <13>, the following steps (β1), (β2), (β3) occurring simultaneously are carried out: (β1) a solution L ₂ <22> comprising the alcohol ROH is passed through I _KK <122>, (β2) a neutral or alkaline aqueous solution L ₃ <23> of a salt S comprising X as a cation is passed through I _KM <132>, then through V _AM <15>, then through I _KA <112>, (β3) voltage is applied between E _A <113> and E _K <123>, whereby the solution L ₁ <21> is obtained at the outlet A _KK <121>, the concentration of XOR in L ₁ <21> being higher than in L ₂ <22>, and whereby at outlet A _KA <111> an aqueous solution L ₄ <24> of S is obtained, the concentration of S in L ₄ <24> being lower than in L ₃ <23>, characterized in that at least one of the following conditions (i), (ii) is met: (i) O _EA <8011> is essentially a plane whose normal N _OEA <91> forms an angle ϕ _EA to the gravity vector V _s <90>, and the flow A _KA <111> is on the upper half of O _EA <8011 > arranged where 0° < ϕ _EA <45°; (ii) O _EK <8012> is essentially a plane whose normal N _OEK <92> forms an angle ϕ _EK to the gravity vector V _s <90>, and the flow A _KK <121> is on the upper half of O _EK <8012> arranged where 0° < ϕ _EK < 45°. A method according to claim 1, wherein both conditions (i) and (ii) are satisfied. The method of claim 2, wherein φ _EK and φ _EA are equal. The method according to any one of claims 1 to 3, wherein the alkali cation-conducting solid electrolyte ceramics comprised by the partition W <16> independently have a structure of the formula M ^I ₁ +2w+x-y+z M ^II w M ^III _x Zr ^IV _2-wxy M ^V _y (SiO ₄ ) _z (PO ₄ ) _3-z have, where M ^I is selected from Na ⁺ , Li ⁺ , M ^II is a divalent metal cation, M ^III is a trivalent metal cation, M ^V is a pentavalent metal cation, the Roman indices I, II, III, IV, V indicate the oxidation numbers in which the respective metal cations are present, and w, x, y, z are real numbers, where 0 ≤ x < 2, 0 y < 2, 0 ≤ w < 2, 0 ≤ z < 3, and where w, x, y, z are chosen such that 1 + 2w + x - y + z ≥ 0 and 2 - w - x - y ≥ 0. A method according to any one of claims 1 to 4, wherein X is selected from the group consisting of Li ⁺ , Na ⁺ , K ⁺ . A method according to claim 5, wherein X = Na ⁺ . A method according to any one of claims 1 to 6, wherein S is a halide, sulfate, sulfite, nitrate, bicarbonate or carbonate of X. A method according to claim 7, wherein S is a chloride of X. A method according to any one of claims 1 to 8, wherein R is selected from the group consisting of methyl, ethyl. A method according to claim 9, wherein R = methyl. A method according to any one of claims 1 to 10, wherein the electrolytic cell E <1> does not comprise a central chamber K _M <13>. The method according to any one of claims 1 to 10, wherein the electrolytic cell E <1> comprises at least one central chamber K _M <13>. The method of claim 12, wherein the connection V _AM <15> is formed within the electrolytic cell E <1>. The method according to claim 12, wherein the connection V _AM <15> is formed outside the electrolytic cell E <1>. The method of claim 14, wherein the following condition (iii) is satisfied: (iii) O _EM is substantially formed as a plane whose normal N _OEM makes an angle ϕ _EM , where 0° < ϕ _EM < 45°, to the gravity vector V _s forms, and the sequence A _KM is arranged on the upper half of O _EM .

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