CONCERTED PROCESSES FOR FORMING 1,2,4-TRIHYDROXYBENZENE FROM HYDROQUINONE

• US 20180105544A1
• Filed: 10/19/2016
• Published: 04/19/2018
• Est. Priority Date: 10/19/2016
• Status: Active Grant

• Current Assignee: Lockheed Martin Corporation (Martin Marietta Corporation)
• Original Assignee: Lockheed Martin Advanced Energy Storage, LLC (Martin Marietta Corporation)
• Inventors: HUMBARGER, Scott Thomas, MILLARD, Matthew
• Granted Patent: US 10,065,977 B2
• Time in Patent Office: Days
• CPC Class Codes: C07C 2601/16 the ring being unsaturated
• CPC Class Codes: C07C 37/0555 being esterified hydroxy groups
• CPC Class Codes: C07C 39/10 Polyhydroxy benzenes; Alkylated derivatives thereof C07C39/08 takes precedence
• CPC Class Codes: C07C 46/06 of at least one hydroxy group on a six-membered aromatic ring
• CPC Class Codes: C07C 50/04 Benzoquinones, i.e. C6H4O2
• CPC Class Codes: C07C 67/04 by reacting carboxylic acids or symmetrical anhydrides onto unsaturated carbon-to-carbon bonds
• CPC Class Codes: C07C 69/18 of trihydroxylic compounds

Abstract

Flow batteries incorporating an active material with one or more catecholate ligands can have a number of desirable operating features. Commercial syntheses of catechol produce significant quantities of hydroquinone as a byproduct, which presently has limited value in the battery industry and can represent a significant waste disposal issue at industrial production scales. Using a concerted, high-yield process, low-value hydroquinone can be transformed into high-value 1,2,4-trihydroxybenzene, which can be a desirable ligand for active materials of relevance in the flow battery industry. Methods for forming 1,2,4-trihydroxybenzene can include: oxidizing hydroquinone in a first reaction to form p-benzoquinone, converting the p-benzoquinone in a second reaction to form 1,2,4-triacetoxybenzene, deacetylating the 1,2,4-triacetoxybenzene in a third reaction to form 1,2,4-trihydroxybenzene, and isolating the 1,2,4-trihydroxybenzene after performing the first reaction, the second reaction and the third reaction consecutively.

Claims

1. A method of producing 1,2,4-trihydroxybenzene comprising the steps of:

(a) mixing p-benzoquinone in the presence of;

(i) at least two equivalents of acetic anhydride per equivalent of the p-benoquinone, and

(ii) a catalytic amount of an acid selected from the group consisting of sulfuric acid, boron trifluoride diethyl etherate, perchloric acid, and trifluoromethanesulfonic acid,

under conditions sufficient to form a crude 1,2,4-triacetoxybenzene mixture comprising 1,2,4-triacetoxybenzene, acetic anhydride, acetic acid, and less than 0.5 mol% of 1,4-diacetoxybenzene relative to the initial p-benzoquinone;

(b) combining the crude 1,2,4-triacetoxybenzene mixture with an excess alcohol sufficient to neutralize excess acetic anhydride in the absence of added water and the presence of an acid catalyst, and heating the resulting reaction mixture under conditions sufficient to form 1,2,4-trihydroxybenzene; and

(c) isolating the 1,2,4-trihydroxybenzene.

3. The method of claim 1, wherein the 1,2,4-triacetoxybenzene is isolated from the crude 1,2,4-triacetoxybenzene mixture by filtration from step (a), but is otherwise used without further purification before forming the 1,2,4-trihydroxybenzene in step (b).

4. The method of claim 1, wherein the crude 1,2,4-triacetoxybenzene mixture contains less than 0.5 mol% of 1,2,4,5-tetraacetoxybenzene.

5. The method of claim 1, wherein steps (a) and (b) are performed consecutively in a single reaction vessel.

11. The method of claim 25, wherein the oxidation of the hydroquinone is done in a solvent in the presence of hydrogen peroxide and a catalytic amount of a source of molecular iodine.

12. The method of claim 11, wherein the solvent is ethyl acetate, isopropanol, an aqueous acid, or any combination thereof.

13. The method of claim 1, wherein step (a) is conducted in the presence of excess acetic anhydride and a catalytic amount of the acid.

14. The method of claim 13, wherein the acid is sulfuric acid.

15. The method of claim 13, wherein step (a) is conducted in the presence of excess acetic anhydride, the catalytic amount of the acid, and acetic acid.

16. The method of claim 13, wherein the p-benzoquinone is added to a mixture of acetic anhydride and the acid at a rate sufficient to maintain a temperature during step (b) between about 40°

C. and about 50°

C.

18. The method of claim 1, wherein the alcohol used in step (b) is methanol.

19. The method of claim 1, further comprising:

reacting the 1,2,4-trihydroxybenzene from step (b) with a transition metal precursor to form a coordination complex having 1,2,4-trihydroxybenzene as at least one ligand.

20. The method of claim 19, wherein the coordination complex has a formula of:

D_gML₁L₂L₃

wherein D is H, ammonium, an alkali metal, or any combination thereof;

g ranges between 0 and 6;

M is a transition metal; and

L₁, L₂ and L₃ are ligands, at least one of L₁, L₂ and L₃ is a 1,2,4-trihydroxybenzene ligand.

21. The method of claim 20, wherein D is ammonium, an alkali metal, or any combination thereof;

g is 2; and

M is Ti.

22. The method of claim 1, wherein the 1,4-diacetoxybenzene formed in step (a) is limited to an amount up to about 0.3%.

23. The method of claim 1, wherein the 1,4-diacetoxybenzene formed in step (a) is limited to an amount up to about 0.2%.

24. The method of claim 1, wherein the 1,4-diacetoxybenzene formed in step (a) is limited to an amount up to about 0.15%.

25. The method of claim 1, wherein step (a) is preceded by a step:

(d) oxidizing hydroquinone to form a crude p-benzophenone product mixture comprising p-benzoquinone.

26. The method of claim 11, wherein the solvent is an alcohol or ethyl acetate that is free from added water.

27. The method of claim 25, wherein the crude p-benzophenone product mixture is used without further purification as the source of the p-benzophenone in step (a).

2. (canceled)

6-10. -10. (canceled)

17. (canceled)