Preparation of titanium catecholate complexes in aqueous solution using titanium tetrachloride or titanium oxychloride

• US 10,253,051 B2
• Filed: 03/15/2016
• Issued: 04/09/2019
• Est. Priority Date: 03/16/2015
• Status: Active Grant

• Current Assignee: Cristal USA Inc. (Ineos AG), Tronox LLC (Tronox Holdings Plc)
• Original Assignee: Cristal USA Inc. (Ineos AG), Lockheed Martin Corporation (Martin Marietta Corporation)
• Inventors: King, Evan R., Pickett, Brian D., Goodman, Malcolm, Fu, Guoyi
• Primary Examiner(s): Cullen, Sean P
• Application Number:
  US15/071,047
• Publication Number:
  US 20160272659A1
• Time in Patent Office: 1,120 Days
• Field of Search: 429101, 429105, 568753
• CPC Class Codes: C07F 7/28 Titanium compounds
• CPC Class Codes: H01M 2300/0002 Aqueous electrolytes
• CPC Class Codes: H01M 8/188 by recharging of redox couples containing fluids; Redox flow type batteries
• CPC Class Codes: Y02E 60/50 Fuel cells

Abstract

Titanium coordination complexes, particularly titanium catecholate complexes, can be attractive active materials for use in flow batteries. However, such coordination complexes can be difficult to prepare from inexpensive starting materials, particularly in aqueous solutions. Titanium oxychloride and titanium tetrachloride represent relatively inexpensive titanium sources that can be used for preparing such coordination complexes. Methods for preparing titanium catecholate complexes can include combining one or more catecholate ligands and titanium oxychloride in an aqueous solution, and reacting the one or more catecholate ligands with the titanium oxychloride in the aqueous solution to form the titanium catecholate complex. Titanium tetrachloride can be used as a precursor for forming the titanium oxychloride in situ. In some instances, the titanium catecholate complex can be isolated in a solid form, which can be substantially free of alkali metal ions.

Claims

1. A method comprising:

reacting one or more catecholate ligands with titanium oxychloride in an aqueous solution to form a titanium catecholate complex.

2. The method of claim 1, further comprising:

reacting the titanium catecholate complex with an aqueous base to form a salt of the titanium catecholate complex having a formula of;

D₂Ti(L₁)(L₂)(L₃);

wherein;

D is NH₄⁺, NR₄⁺, Li⁺, Na⁺, K⁺, or any combination thereof, where R is alkyl; and

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

3. The method of claim 1, wherein the substituted catecholate ligand contains a hydroxy group in the 3- or 4-position.

4. The method of claim 1, wherein the aqueous solution has a pH in a range of from 2.5 to 7.

5. The method of claim 4, wherein the titanium catecholate complex is isolated from the aqueous solution as a solid.

6. The method of claim 1, wherein the titanium catecholate complex has a formula of:

H₂Ti(L₁)(L₂)(L₃);

wherein;

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

7. The method of claim 6, wherein each of L₁, L₂ and L₃ are a catecholate ligand or a substituted catecholate ligand.

8. The method of claim 6, wherein the titanium catecholate complex is isolated from the aqueous solution as a solid.

9. The method of claim 6, further comprising:

reacting the titanium catecholate complex with an aqueous base to form a salt of the titanium catecholate complex having a formula of;

D₂Ti(L₁)(L₂)(L₃);

wherein;

D is NH₄⁺, NR₄⁺, Li⁺, Na⁺, K⁺, or any combination thereof, where R is alkyl.

10. The method of claim 1, wherein at least a portion of the one or more catecholate ligands comprise a substituted catecholate ligand.

11. The method of claim 10, wherein the substituted catecholate ligand has a structure of:

12. The method of claim 10, wherein the titanium catecholate complex has a formula of:

D₂Ti(L₁)(L₂)(L₃);

wherein;

D is H, NH₄⁺, NR₄⁺, Li⁺, Na⁺, K⁺, or any combination thereof, where R is alkyl; and

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

13. The method of claim 12, wherein each of L₁, L₂ and L₃ are a catecholate ligand or a substituted catecholate ligand.

14. The method of claim 1, further comprising:

combining titanium tetrachloride with water at conditions under which the titanium tetrachloride reacts with the water to form the titanium oxychloride; and

optionally diluting the titanium oxychloride to form the aqueous solution.

15. The method of claim 14, wherein the titanium tetrachloride reacts with the water at a temperature in a range of from −

10°

C. to −

40°

C.

16. The method of claim 14, wherein the one or more catecholate ligands are combined with the aqueous solution after the titanium oxychloride has been formed.

17. The method of claim 14, wherein the conditions under which the titanium tetrachloride reacts with the water are such that titanium dioxide is not formed.

18. The method of claim 14, wherein the aqueous solution has a pH in a range of from 2.5 to 7.

19. The method of claim 14, wherein the titanium tetrachloride reacts with the water at a temperature below about 0°

C.

20. The method of claim 19, wherein the water is added to the titanium tetrachloride as ice and the titanium tetrachloride is also in a solid form.