COORDINATION COMPLEXES CONTAINING MONOSULFONATED CATECHOLATE LIGANDS AND METHODS FOR PRODUCING THE SAME

• US 20170256811A1
• Filed: 03/03/2016
• Published: 09/07/2017
• Est. Priority Date: 03/03/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Advanced Energy Storage, LLC (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Advanced Energy Storage, LLC (Martin Marietta Corporation)
• Inventors: HUMBARGER, Scott Thomas, Millard, Matthew
• Granted Patent: US 10,644,342 B2
• Time in Patent Office: Days
• CPC Class Codes: C07C 37/00 Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom of a six-membered aromatic ring
• CPC Class Codes: C07F 7/28 Titanium compounds
• CPC Class Codes: H01B 1/121 Charge-transfer complexes
• CPC Class Codes: H01M 10/36 Accumulators not provided for in groups H01M10/05-H01M10/34
• CPC Class Codes: H01M 8/08 Fuel cells with aqueous electrolytes
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: H01M 8/20 Indirect fuel cells, e.g. fuel cells with redox couple being irreversible H01M8/18 takes precedence
• CPC Class Codes: Y02E 60/10 Energy storage using batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Flow batteries and other electrochemical systems can contain an active material that is a coordination complex having at least one monosulfonated catecholate ligand or a salt thereof bound to a metal center. The monosulfonated catecholate ligand has a structure of

More particularly, the coordination complex can be a titanium coordination complex with a formula of D_gTi(L₁)(L₂)(L₃), in which D is a counterion selected from H, NH₄^|, Li^|, Na^|, K^|, or any combination thereof g ranges between 3 and 6; and L₁, L₂ and L₃ are ligands, where at least one of L₁, L₂ and L₃ is a monosulfonated catecholate ligand. Methods for synthesizing such monosulfonated catecholate ligands can include providing a neat mixture of catechol and up to about 1.3 stoichiometric equivalents of sulfuric acid, and heating the neat mixture at a temperature of about 80° C. or above to form 3,4-dihydroxybenzenesulfonic acid or a salt thereof.

Claims

1. A composition comprising:

a coordination complex having at least one monosulfonated catecholate ligand or a salt thereof bound to a metal center;

wherein the at least one monosulfonated catecholate ligand has a structure of

2. The composition of claim 1, wherein the metal center is a transition metal.

3. The composition of claim 2, wherein the transition metal is Ti.

4. The composition of claim 3, wherein the coordination complex has a formula of

D_gTi(L₁)(L₂)(L₃);

wherein D is a counterion selected from H, NH₄^|, Li^|, Na^|, K^|, or any combination thereof;

g ranges between 3 and 6; and

L₁, L₂ and L₃ are ligands, at least one of L₁, L₂ and L₃ being a monosulfonated catecholate ligand.

5. The composition of claim 4, wherein each of L₁, L₂ and L₃ are monosulfonated catecholate ligands and g is 5 or 6.

6. The composition of claim 4, wherein one of L₁, L₂ and L₃ is a monosulfonated catecholate ligand and g is 3 or 4.

7. The composition of claim 6, wherein two of L₁, L₂ and L₃ are non-sulfonated catecholate ligands.

8. The composition of claim 7, wherein two of L₁, L₂ and L₃ are unsubstituted catecholate ligands.

9. The composition of claim 4, wherein the coordination complex comprises both Na⁺ and K⁺ counterions.

10. The composition of claim 4, wherein two of L₁, L₂ and L₃ are monosulfonated catecholate ligands, one of L₁, L₂ and L₃ is a non-sulfonated catecholate ligand, and g is 4 or 5.

11. The composition of claim 10, wherein one of L₁, L₂ and L₃ is an unsubstituted catecholate ligand.

12. The composition of claim 4, further comprising:

an aqueous solution in which the coordination complex is dissolved.

13. The composition of claim 12, wherein the aqueous solution has an alkaline pH.

14. The composition of claim 1, wherein the coordination complex has an overall negative charge and comprises both Na⁺ and K⁺ counterions.

15. The composition of claim 1, further comprising:

an aqueous solution in which the coordination complex is dissolved.

16. The composition of claim 15, wherein the aqueous solution has an alkaline pH.

17. A flow battery comprising:

a first half-cell having a first electrolyte solution therein, the first electrolyte solution comprising an aqueous solution comprising the composition of claim 4.

18. The flow battery of claim 17, further comprising:

a second half-cell having a second electrolyte solution therein, the second electrolyte solution comprising an aqueous solution comprising an iron hexacyanide complex.

19. A method comprising:

providing a neat mixture of catechol and up to about 1.3 stoichiometric equivalents of sulfuric acid; and

heating the neat mixture at a temperature of about 80°

C. or above to form a reaction product comprising 3,4-dihydroxybenzenesulfonic acid or a salt thereof.

20. The method of claim 19, wherein less than about 5% of the catechol is converted into 2,3-dihydroxybenzenesulfonic acid or a salt thereof.

21. The method of claim 19, wherein the neat mixture contains between about 0.8 and 1.2 stoichiometric equivalents of sulfuric acid.

22. The method of claim 19, wherein the neat mixture contains between about 0.3 and about 0.5 stoichiometric equivalents of sulfuric acid.

23. The method of claim 19, wherein the neat mixture is heated at a temperature ranging between about 80°

C. and about 110°

C.

24. The method of claim 19, wherein the neat mixture is heated at a temperature ranging between about 80°

C. and about 100°

C.

25. The method of claim 19, further comprising:

isolating the 3,4-dihydroxybenzenesulfonic acid or a salt thereof from the reaction product.

26. The method of claim 25, further comprising:

treating the reaction product with a base before isolating the 3,4-dihydroxybenzenesulfonic acid or a salt thereof.

27. The method of claim 25, further comprising:

reacting the 3,4-dihydroxybenzenesulfonic acid or a salt thereof with a transition metal compound to form a coordination complex having at least one sulfonated catecholate ligand bound to a metal center.

28. The method of claim 27, wherein a mixture of catechol and 3,4-dihydroxybenzenesulfonic acid or a salt thereof is reacted with the transition metal compound to form the coordination complex.

29. The method of claim 27, wherein the transition metal compound is a titanium compound.