PROCESSES FOR FORMING COORDINATION COMPLEXES CONTAINING MONOSULFONATED CATECHOLATE LIGANDS

• US 20170253620A1
• 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 10,316,047 B2
• Time in Patent Office: Days
• CPC Class Codes: C07C 303/06 by reaction with sulfuric acid or sulfur trioxide
• CPC Class Codes: C07C 303/32 of salts of sulfonic acids
• CPC Class Codes: C07C 309/42 having the sulfo groups bound to carbon atoms of non-condensed six-membered aromatic rings
• CPC Class Codes: C07C 37/66 by conversion of hydroxy groups to O-metal groups
• CPC Class Codes: C07C 39/235 Metal derivatives of a hydroxy group bound to 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 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 8/222 Fuel cells in which the fuel is based on compounds containing nitrogen, e.g. hydrazine, ammonia
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Coordination complexes can have a metal center with at least one unsubstituted catecholate ligand and at least one monosulfonated catecholate ligand or a salt thereof bound thereto. Some coordination complexes can have a formula of D_gTi(L₁)_x(L₂)_y, in which D is a counterion selected from NH₄⁺, Li⁺, Na⁺, K⁺, or any combination thereof; g ranges between 2 and 6; L₁ is an unsubstituted catecholate ligand; L₂ is a monosulfonated catecholate ligand; and x and y are non-zero numbers such that x+y=3. Methods for synthesizing such coordination complexes can include providing a neat mixture of catechol and a sub-stoichiometric amount of sulfuric acid, heating the neat mixture to form a reaction product containing catechol and a monosulfonated catechol or a salt thereof, and forming a coordination complex from the reaction product without separating the catechol and the monosulfonated catechol or the salt thereof from one another.

Claims

1. A method comprising:

providing a neat mixture of catechol and a sub-stoichiometric amount of sulfuric acid relative to the catechol;

heating the neat mixture to form a reaction product comprising a mixture of catechol and a monosulfonated catechol or a salt thereof; and

without separating the catechol and the monosulfonated catechol or the salt thereof from one another, forming a coordination complex from the reaction product having a metal center with at least one unsubstituted catecholate ligand and at least one monosulfonated catecholate ligand bound thereto.

2. The method of claim 1, wherein the monosulfonated catechol is 3,4-dihydroxybenzenesulfonic acid.

3. The method of claim 1, wherein the neat mixture comprises up to about 0.7 stoichiometric equivalents of sulfuric acid relative to catechol.

4. The method of claim 3, wherein the neat mixture comprises between about 0.1 stoichiometric equivalents and about 0.7 stoichiometric equivalents of sulfuric acid relative to catechol.

5. The method of claim 3, wherein the neat mixture comprises between about 0.3 stoichiometric equivalents and about 0.5 stoichiometric equivalents of sulfuric acid relative to catechol.

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

C. and about 130°

C.

7. The method of claim 1, wherein the coordination complex comprises a transition metal.

8. The method of claim 7, wherein the transition metal is titanium and the coordination complex has a formula of

D_gTi(L₁)_x(L₂)_y;

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

g ranges between 2 and 6;

L₁ is the at least one unsubstituted catecholate ligand;

L₂ is the at least one monosulfonated catecholate ligand; and

x and y are non-zero numbers such that x+y=3.

9. The method of claim 8, wherein the coordination complex comprises both Na⁺ and K⁺ counterions.

10. The method of claim 1, further comprising:

combining at least one aqueous base with the coordination complex; and

obtaining an aqueous solution of the coordination complex.

11. The method of claim 10, wherein the coordination complex comprises both Na⁺ and K⁺ counterions.

12. The method of claim 10, wherein the metal center is titanium.

13. The method of claim 1, further comprising:

combining an organic solvent with the reaction product before forming the coordination complex.

14. The method of claim 1, wherein the reaction product and the coordination complex are formed consecutively in a single reaction vessel.

15. A method comprising:

providing a neat mixture of catechol and up to about 0.7 stoichiometric equivalents of sulfuric acid relative to the catechol;

heating the neat mixture at a temperature of about 80°

C. or above to form a reaction product comprising a mixture of catechol and a monosulfonated catechol or a salt thereof, the monosulfonated catechol being 3,4-dihydroxybenzenesulfonic acid;

without separating the catechol and the monosulfonated catechol or the salt thereof from one another, forming a coordination complex from the reaction product having a metal center with at least one unsubstituted catecholate ligand and at least one monosulfonated catecholate ligand bound thereto;

combining an aqueous base with the coordination complex; and

obtaining an aqueous solution of the coordination complex.

16. The method of claim 15, wherein the neat mixture comprises between about 0.1 stoichiometric equivalents and about 0.7 stoichiometric equivalents of sulfuric acid relative to catechol.

17. The method of claim 15, wherein the neat mixture comprises between about 0.3 stoichiometric equivalents and about 0.5 stoichiometric equivalents of sulfuric acid relative to catechol.

18. The method of claim 15, wherein the neat mixture is heated at a temperature ranging between about 80°

C. and about 130°

C.

19. The method of claim 15, wherein the coordination complex comprises a transition metal.

20. The method of claim 19, wherein the transition metal is titanium and the coordination complex has a formula of

D_gTi(L₁)_x(L₂)_y;

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

g ranges between 2 and 6;

L₁ is the at least one unsubstituted catecholate ligand;

L₂ is the at least one monosulfonated catecholate ligand; and

x and y are non-zero numbers such that x+y=3.

21. The method of claim 20, wherein the coordination complex comprises both Na⁺ and K⁺ counterions.

22. The method of claim 15, further comprising:

adding an organic solvent to the reaction product before forming the coordination complex.

23. A composition comprising:

a coordination complex dissolved in an aqueous solution having an alkaline pH, the coordination complex having a metal center with at least one unsubstituted catecholate ligand and at least one monosulfonated catecholate ligand or a salt thereof bound thereto, the at least one monosulfonated catecholate ligand being 3,4-dihydroxybenzenesulfonic acid;

wherein the coordination complex bears an overall negative charge and at least one positively charged monovalent counterion maintains charge balance.

24. The composition of claim 23, wherein the coordination complex comprises a transition metal.

25. The composition of claim 24, wherein the transition metal is titanium and the coordination complex has a formula of

D_gTi(L₁)_x(L₂)_y;

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

g ranges between 2 and 6;

L₁ is the at least one unsubstituted catecholate ligand;

L₂ is the at least one monosulfonated catecholate ligand; and

x and y are non-zero numbers such that x+y=3.

26. The composition of claim 25, wherein the coordination complex comprises both Na⁺ and K⁺ counterions.

27. A flow battery comprising:

a first half-cell having a first electrolyte solution therein, the first electrolyte solution comprising the composition of claim 25.

28. The flow battery of claim 27, 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.