Method for producing alkali metal alcoholates in an electrolysis cell

Patent metadata

Field	Value
Publication number	US-12503783-B2
Application number	US-202218688762-A
Country	US
Kind code	B2
Filing date	Aug 19, 2022
Priority date	Sep 6, 2021
Publication date	Dec 23, 2025
Grant date	Dec 23, 2025

Abstract

The invention relates to a method for producing an alkali metal alcoholate solution L 1 in an electrolysis cell E which comprises at least one cathode chamber K K , at least one anode chamber K A , and at least one central chamber K M lying therebetween. The interior I KK of the cathode chamber K K is separated from the interior I KM of the central chamber K M by a separating wall W comprising at least one alkali-cation-conductive solid ceramic electrolyte (=“AFK”) F (e.g. NaSICON). During the electrolysis process for producing the alkali metal alcoholates with F instead of F′, an improved conductivity is provided, whereby for a constant current density, a lower voltage can be used.

First claim

The invention claimed is:

1 . A process for producing a solution L 1 < 21 > of an alkali metal alkoxide XOR in an alcohol ROH, in an electrolysis cell E < 1 >, where X is an alkali metal cation and R is an alkyl radical having 1 to 4 carbon atoms, said process comprising the following steps:
(i) providing an alkali metal cation-conducting solid-state electrolyte ceramic F′ < 19 > having a surface O F′ < 190 >;
(ii) removing a portion of the alkali metal cation-conducting solid-state electrolyte ceramic F′ < 19 > by compressed air blasting with a solid blasting abrasive N < 30 >, which produces an alkali metal cation-conducting solid-state electrolyte ceramic F < 18 > having a surface O F < 180 > which differs from the surface O F < 190 > in at least one subregion O FΔ < 183 >, wherein the surface O F < 180 > comprises the surfaces O A/MK < 181 > and O KK < 182 > and wherein O A/MK < 181 > and/or O KK < 182 > comprise at least a portion of O FΔ < 183 >;
(iii) arranging the alkali metal cation-conducting solid-state electrolyte ceramic F < 18 > in the electrolysis cell E < 1 >, wherein said electrolysis cell comprises at least one anode chamber K A < 11 >, at least one cathode chamber K K < 12 > and at least one interposed middle chamber K M < 13 >;
wherein the at least one anode chamber K A < 11 > comprises:
at least one inlet Z KA < 110 >;
at least one outlet A KA < 111 >;
and an interior I KA < 112 > with an anodic electrode E A < 113 >;

the at least one cathode chamber K K < 12 > comprises:
at least one inlet Z KK < 120 >;
at least one outlet A KK < 121 >;
and an interior I KK < 122 > with a cathodic electrode E K < 123 >;

and the at least one middle chamber K M < 13 > comprises:
at least one inlet Z KM < 130 >;
at least one outlet A KM < 131 >;
and an interior I KM < 132 >;

wherein I KA < 112 > and I KM < 132 > are divided from one another by a diffusion barrier D < 14 >, and A KM < 131 > is connected by a connection V AM < 15 > to the inlet Z KA < 110 >, such that liquid can be passed from I KM < 132 > into I KA < 112 > via the connection V AM < 15 >;
I KK < 122 > and I KM < 132 > are divided from one another by a dividing wall W < 16 >comprising the alkali metal cation-conducting solid-state electrolyte ceramic F < 18 >, wherein F < 18 >makes direct contact with the interior I KK < 122 > via the surface O KK < 182 > and with the interior I KM < 132 > via the surface O A/MK < 181 >,

(iv-β) and wherein the following steps (β 1 ), (β 2 ), (β 3 ) proceed simultaneously:
(β 1 ) a solution L 2 < 22 > comprising the alcohol ROH is routed through I KK < 122 >, wherein, when O KK < 182 > includes at least a portion of O FΔ < 183 >, the solution L 2 < 22 >makes direct contact with the at least on subregion O FΔ < 183 >;
(β 2 ) a neutral or alkaline, aqueous solution L 3 < 23 >of a salt S comprising X as cation is routed through I KM < 132 >, then via V AM < 15 > through I KA < 112 >, where, when O A/MK < 181 > includes at least a portion of O FΔ < 183 >, the solution L 3 < 23 > makes direct contact with the at least on subregion O FΔ < 183 >;

(β 3 ) voltage is applied between E A < 113 > and E K < 123 >, thereby providing solution L 1 < 21 > at the outlet A KK < 121 >, with a higher concentration of XOR than in L 2 < 22 >, and providing aqueous solution L 4 < 24 > of S at the outlet A KA < 111 >, with a lower concentration of S than in L 3 < 23 >.

2 . The process of claim 1 , wherein: S MF′ <S MF ; and wherein S MF′ is the mass-based specific surface area S M of the alkali metal cation-conducting solid-state electrolyte ceramic F′ before performance of step (ii) and S MF is the mass-based specific surface area S M of the alkali metal cation-conducting solid-state electrolyte ceramic F after performance of step (ii).

3 . The process of claim 2 , wherein the quotient S MF /S MF′ ≥1.01.

4 . The process of claim 1 , wherein at least 1% of the surface O A/MK < 181 > is formed by O FA < 183 > and/or at least 1% of the surface O KK < 182 > is formed by O FΔ < 183 >.

5 . The process of claim 4 , wherein the alkali metal cation-conducting solid-state electrolyte ceramic F′ < 19 >has a structure of the formula:
M I 1+2w+x−y+z M II w M III x Zr IV 2−w−x−y M V y (SiO 4 ) z (PO 4 ) 3−z
where M I is selected from Na + and Li + ;
M II is a divalent metal cation;
M III is a trivalent metal cation;
M V is a pentavalent metal cation;
the Roman indices I, II, III, IV, V indicate the oxidation numbers in which the respective metal cations exist;
wherein w, x, y, z are real numbers, wherein 0≤x<2, 0≤y<2,0≤w<2,0≤z<3;
and wherein w, x, y, z are chosen such that 1+2w +x−y+z≥0 and 2−w−x−y≥0.

6 . The process of claim 5 , wherein X is selected from the group consisting of Li + , Na + , and K + .

7 . The process of claim 6 , wherein X=Na + .

8 . The process of claim 6 , wherein S is a halide, sulfate, sulfite, nitrate, hydrogencarbonate or carbonate of X.

9 . The process of claim 8 , wherein S is a chloride of X and R is selected from the group consisting of methyl and ethyl.

10 . The process of claim 1 , wherein the alkali metal cation-conducting solid-state electrolyte ceramic F′ < 19 >has a structure of the formula:
M I 1+2w+x−y+z M II w M III x Zr IV 2−w−x−y M V y (SiO 4 ) z (PO 4 ) 3−z
where M I is selected from Na + and Li + ;
M II is a divalent metal cation;
M III is a trivalent metal cation;
M V is a pentavalent metal cation;
the Roman indices I, II, III, IV, V indicate the oxidation numbers in which the respective metal cations exist;
wherein w, x, y, z are real numbers, wherein 0≤x<2, 0≤y<2,0≤w<2,0≤z<3;
and wherein w, x, y, z are chosen such that 1+2w +x−y+z≥0 and 2−w−x−y≥0.

11 . The process of claim 1 , wherein X is selected from the group consisting of Li + , Na + , and K + .

12 . The process of claim 11 , wherein X=Na + .

13 . The process of claim 1 , wherein S is a halide, sulfate, sulfite, nitrate, hydrogencarbonate or carbonate of X.

14 . The process of claim 13 , wherein S is a chloride of X.

15 . The process of claim 1 , wherein R is selected from the group consisting of methyl and ethyl.

16 . The process of claim 15 , wherein R=methyl.

17 . The process of claim 1 , wherein connection V AM < 15 > is formed within the electrolysis cell E < 1 >.

18 . The process of claim 1 , wherein the connection V AM < 15 > is formed outside the electrolysis cell E < 1 >.

19 . The process of claim 1 , wherein O A/MK < 181 > and O KK < 182 > comprise at least a portion of O FΔ < 183 >.

20 . The process of claim 19 , wherein at least 1 % of the surface O A/MK < 181 > is formed by O FΔ < 183 > and at least 1% of the surface O KK < 182 > is formed by O FΔ < 183 >.

Assignees

• Evonik Operations Gmbh

Inventors

• Reinsberg Philip Heinrich
• Horn Michael
• Teufert Rüdiger
• Weiner Marc

Classifications

• C25B3/13

  Organo-metallic compounds · CPC title

• C25B9/60

  Constructional parts of cells · CPC title

• C25B3/07 Primary

  Oxygen containing compounds · CPC title

• C25B13/07 Primary

  based on ceramics · CPC title

• C25B9/21

  two or more diaphragms · CPC title