Coordination complexes containing monosulfonated catecholate ligands and methods for producing the same

• US 10,644,342 B2
• Filed: 03/03/2016
• Issued: 05/05/2020
• Est. Priority Date: 03/03/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Advanced Energy Storage, LLC (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: Humbarger, Scott Thomas, Millard, Matthew
• Primary Examiner(s): Kopec, Mark
• Application Number:
  US15/060,493
• Publication Number:
  US 20170256811A1
• Time in Patent Office: 1,524 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 method comprising heating a neat mixture of catechol and a sub-stoichiometric amount of sulfuric acid at a temperature in a range of from about 80°

C. to about 130°

C. to form a reaction product comprising unreacted catechol and 3,4-dihydroxybenzenesulfonic acid.

2. The method of claim 1, wherein the reaction product comprises less than about 5% of 2,3-dihydroxybenzenesulfonic acid.

3. The method of claim 1, wherein the neat mixture contains between about 0.2 and 0.4 stoichiometric equivalents of sulfuric acid per catechol.

4. The method of claim 3, wherein the reaction product is a mixture of unreacted catechol and 3,4-dihydroxybenzenesulfonic acid in a molar ratio of 2:

1.

5. The method of claim 4, further comprising treating the reaction product with a base to form a desired salt form of the reaction product before further using the reaction mixture.

6. The method of claim 5, further comprising reacting the salt form of the reaction product with a transition metal compound to form a transition metal coordination complex having one sulfonated catecholate ligand and two unsubstituted catecholate ligands bound to a metal center, wherein the sulfonated catechol ligand is a salt form of 3,4-dihydroxybenzenesulfonic acid.

7. The method of claim 6, wherein the transition metal compound is a titanium compound.

8. The method of claim 5, wherein the base comprises an alkali metal hydroxide, alkali metal carbonate, alkali metal bicarbonate, ammonium hydroxide, ammonium carbonate, or ammonium bicarbonate.

9. The method of claim 5, wherein the base is lithium hydroxide, sodium hydroxide, potassium hydroxide, or a mixture thereof.

10. The method of claim 4, wherein the reaction product is reacted with a transition metal compound to form a transition metal coordination complex having one sulfonated catecholate ligand and two unsubstituted catecholate ligands bound to a metal center, and wherein the sulfonated catechol ligand is a salt form of 3,4-dihydroxybenzenesulfonic acid.

11. The method of claim 10, wherein the transition metal compound is a titanium compound.

12. The method of claim 1, wherein the neat mixture contains between about 0.3 and about 0.5 stoichiometric equivalents of sulfuric acid per catechol.

13. The method of claim 12, wherein the neat mixture contains about 0.5 stoichiometric equivalents of sulfuric acid per catechol, resulting in a reaction product that is a mixture of unreacted catechol and 3,4-dihydroxybenzenesulfonic acid in a molar ratio of 1:

1, the method further comprising treating the reaction product with a base to form a desired salt form before further using the reaction mixture.

14. The method of claim 13, wherein the base comprises an alkali metal hydroxide, alkali metal carbonate, alkali metal bicarbonate, ammonium hydroxide, ammonium carbonate, or ammonium bicarbonate.

15. The method of claim 13, wherein the base is lithium hydroxide, sodium hydroxide, potassium hydroxide, or a mixture thereof.

16. The method of claim 13, further comprising reacting the salt form of the reaction product with a transition metal compound to form a transition metal coordination complex having one sulfonated catecholate ligand and one unsubstituted catecholate ligand bound to a metal center, wherein the sulfonated catechol ligand is a salt form of 3,4-dihydroxybenzenesulfonic acid.

17. The method of claim 1, wherein the neat mixture is heated at a temperature ranging between about 80°

C. and about 110°

C.

18. The method of claim 1, wherein the neat mixture is heated at a temperature ranging between about 80°

C. and about 100°

C.