Oxidation chemistry on furan aldehydes
Provided herein are methods of producing halomethylfuroic and acyloxymethylfuroic acid and ester compounds from furfural starting compounds. For example, 5-chloromethyl-2-furoic acid may be produced from 5-chloromethylfurfural, in the presence of various oxidants. Salts of the furoic acids may also be produced.
1. A method of producing a halomethylfuroic acid, or a salt thereof, comprising combining a halomethylfurfural, an organosulfur compound, and an oxidant to produce a halomethylfuroic acid, or a salt thereof,
wherein the oxidant is:
(i) a compound of formula W b -O 2 X b , wherein W b is a Group I cation and X b is halo;
(ii) a compound of formula W d -O 3 X d , wherein W d is a Group I cation and X d is halo;
(iii) a compound of formula HX b O 2 , wherein X b is halo;
(iv) a compound of formula HX d O 3 , wherein X d is halo; or
(v) a compound of formula X c O 2 , wherein X c is halo.
2. The method of claim 1 , wherein the oxidant is HClO 2 or ClO 2 .
3. The method of claim 1 , wherein the organosulfur compound is dimethyl sulfoxide.
4. The method of claim 1 , wherein the halomethylfurfural, the organosulfur compound and the oxidant are further combined with an acid.
5. The method of claim 4 , wherein the acid is hydrochloric acid.
6. The method of claim 1 , wherein the halomethylfurfural, the organosulfur compound and the oxidant are combined with water to form a reaction mixture, wherein the reaction mixture has a pH, and
wherein the method comprises adjusting the pH of the reaction mixture to a pH of between 0 and 5.
7. The method of claim 1 , wherein the oxidant is a compound of formula W b -O 2 X b , wherein W b is a Group I cation and X b is halo.
8. The method of claim 7 , wherein W b is sodium, lithium or potassium.
9. The method of claim 7 , wherein X b is chloro or bromo.
10. The method of claim 7 , wherein the oxidant is sodium chlorite, lithium chlorite, potassium chlorite, or sodium bromite.
11. A method of producing a halomethylfuroic acid, or a salt thereof, comprising combining a halomethylfurfural and an oxidant to produce a halomethylfuroic acid, or a salt thereof, wherein the oxidant is a compound of formula W d -O 3 X d , wherein W d is a Group I cation and X d is halo.
12. The method of claim 11 , wherein W d is sodium, lithium or potassium.
13. The method of claim 11 , wherein X d is chloro or bromo.
14. The method of claim 11 , wherein the oxidant is sodium chlorate, potassium chlorate, lithium chlorate, or sodium bromate.
15. The method of claim 1 , wherein the oxidant is a compound of formula HX b O 2 , wherein X b is halo.
16. The method of claim 15 , wherein X b is chloro or bromo.
17. A method of producing a halomethylfuroic acid, or a salt thereof, comprising combining a halomethylfurfural and an oxidant to produce a halomethylfuroic acid, or a salt thereof, wherein the oxidant is a compound of formula HX d O 3 , wherein X d is halo.
18. The method of claim 17 , wherein X d is chloro or bromo.
19. The method of claim 1 , wherein the oxidant is a compound of formula X c O 2 , wherein X c is halo.
20. The method of claim 19 , wherein X c is chloro or bromo.
21. The method of claim 1 , wherein the halomethylfurfural is 5-chloromethylfurfural, and wherein the halomethylfuroic acid, or a salt thereof, is 5-chloromethyl-2-furoic acid, or a salt thereof.
22. The method of claim 1 , wherein the halomethylfurfural, the organosulfur compound and the oxidant are further combined with water.
23. The method of claim 1 , wherein the halomethylfuroic acid is produced at a yield of at least 50%.
24. The method of claim 1 , wherein the halomethylfurfural the organosulfur compound and the oxidant are further combined with solvent.
25. The method of claim 24 , wherein the solvent comprises an organic solvent.
26. The method of claim 25 , wherein the solvent comprises acetic acid, dimethyl sulfoxide, dimethoxyethane, tetrahydrofuran, or acetonitrile, or any combinations thereof.
27. The method of claim 1 , wherein the halomethylfurfural the organosulfur compound and the oxidant are further combined with an alkene, or a peroxide, or any combinations thereof.
28. The method of claim 1 , wherein the halomethylfurfural the organosulfur compound and the oxidant are further combined with a buffer.
29. The method of claim 28 , wherein the buffer is a phosphate buffer.
30. The method of claim 1 , wherein the halomethylfurfural the organosulfur compound and the oxidant are further combined with an acid.
31. The method of claim 30 , wherein the acid is hydrochloric acid.
32. The method of claim 1 , wherein the mole ratio of the oxidant to the halomethylfurfural is between 0.1 and 4.0.
33. The method of claim 1 , wherein the oxidant is chlorous acid or chlorine dioxide, further comprising:
producing hypochlorous acid from the chlorous acid or chlorine dioxide, and
removing the hypochlorous acid produced.
34. The method of claim 33 , wherein the removing is performed with an alkene, or a peroxide, or any combinations thereof.
35. The method of claim 33 , wherein less than 5 wt % of sodium hypochlorite is present relative to the oxidant.
36. The method of claim 1 , wherein the oxidant is produced in situ.
37. The method of claim 1 , wherein the oxidant is produced in situ from sodium halite and an acid.
38. The method of claim 1 , further comprising isolating the halomethylfuroic acid, or a salt thereof, produced.
39. The method of claim 38 , wherein the isolating comprises liquid-liquid extraction.
40. The method of claim 38 , wherein the liquid-liquid extraction is performed with a haloalkyl solvent.
41. The method of claim 40 , wherein the haloalkyl solvent comprises dichloromethane, chloroform, or dichloroethane, or any combinations thereof.
42. The method of claim 1 , wherein less than 50% of the halomethyl group of the halomethylfurfural is hydrolyzed to a hydroxymethyl group.
43. The method of claim 1 , wherein the halomethylfuroic acid, or a salt thereof, is a solid.
44. The method of claim 1 , wherein the organosulfur compound is thiodiethanol.
45. The method of claim 11 , wherein the halomethylfurfural and the oxidant are further combined with an organosulfur compound.
46. The method of claim 45 , wherein the organosulfur compound is dimethyl sulfoxide.
47. The method of claim 45 , wherein the organosulfur compound is dimethyl thiodiethanol.
48. The method of claim 17 , wherein the halomethylfurfural and the oxidant are further combined with an organosulfur compound.
49. The method of claim 48 , wherein the organosulfur compound is dimethyl sulfoxide.
50. The method of claim 48 , wherein the organosulfur compound is dimethyl thiodiethanol.