Production of glutaric acid and derivatives from carbohydrate-containing materials
The present invention generally relates to processes for the chemocatalytic conversion of a pentose source to a glutaric acid product. The present invention includes processes for the conversion of pentose to a glutaric acid product via pentaric acid or derivatives thereof. The present invention also includes processes comprising the catalytic oxidation of pentose to pentaric acid and catalytic hydrodeoxygenation of pentaric acid or derivatives thereof to a glutaric acid product.
1. A process for preparing a C5-backbone substrate, the process comprising:
reacting a pentose with oxygen in the presence of a heterogeneous oxidation catalyst comprising a metal selected from the group consisting of Pd, Pt, and combinations thereof to convert at least a portion of the pentose to the C5-backbone substrate, wherein the pH of the reaction mixture is no greater than about 7 and the C5-backbone substrate is a compound of formula I or lactone thereof:
wherein X is independently hydroxyl, oxo, halo, acyloxy or hydrogen provided that at least one X is not hydrogen and R 1 is independently a salt-forming ion, hydrogen, hydrocarbyl, or substituted hydrocarbyl.
2. The process of claim 1 wherein X is hydroxyl and R 1 is independently a salt-forming ion, hydrogen, hydrocarbyl, or substituted hydrocarbyl.
3. The process of claim 1 wherein the C5-backbone substrate comprises a pentaric acid.
4. The process of claim 3 wherein the pentaric acid comprises an acid selected from the group consisting of xylaric acid, arabinaric acid, ribaric acid, and combinations thereof.
5. The process of claim 1 wherein C5-backbone substrate comprises xylaric acid.
6. The process of claim 4 wherein the weight ratio of pentose to Pd and/or Pt is no greater than about 65:1.
7. The process of claim 1 wherein the heterogeneous oxidation catalyst comprises Pt.
8. The process of claim 1 wherein the weight ratio of pentose to Pd and/or Pt is no greater than about 65:1.
9. The process of claim 1 wherein the metal constitutes from about 0.25% to about 10% of the total weight of the catalyst.
10. The process of claim 9 wherein the metal constitutes from about 1% to about 8% of the total weight of the catalyst.
11. The process of claim 1 wherein the heterogeneous oxidation catalyst comprises a catalyst support selected from the group consisting of carbon, alumina, silica, titania, zirconia, and zeolite.
12. The process of claim 1 wherein the pH of the reaction mixture is less than 6.
13. The process of claim 1 wherein the reaction is conducted essentially free of added base.
14. The process of claim 1 wherein the reaction is conducted in the essential absence of nitrogen as an active reaction constituent.
15. The process of claim 1 wherein the reaction mixture is free of nitrates and nitric acid.
16. The process of claim 1 wherein at least a portion of the pentose is solubilized with a weak carboxylic acid.
17. The process of claim 16 wherein the weak carboxylic acid is acetic acid.
18. The process of claim 1 wherein the reaction mixture is maintained at a temperature of at least about 60° C.
19. The process of claim 1 wherein the temperature of the reaction mixture is from about 60° C. to about 150° C.
20. The process of claim 1 wherein the reaction is conducted under a partial pressure of oxygen in the range of from about 15 psia (104 kPa) to about 2000 psia (13790 kPa).
21. The process of claim 1 wherein at least a portion of the pentose is obtained from a carbohydrate source.
22. The process of claim 21 wherein the pentose is selected from the group consisting of xylose, arabinose, and ribose.
23. The process of claim 1 wherein the oxygen is supplied to the reaction as air, oxygen-enriched air, oxygen alone, or oxygen with one or more other constituents substantially inert to the reaction.
24. The process of claim 1 wherein the yield of C5-backbone substrate is at least about 15%.
25. The process of claim 4 wherein the yield of pentaric acid is at least about 15%.
26. The process of claim 1 wherein the yield of C5-backbone substrate is at least about 30%.
27. The process of claim 4 wherein the pH of the reaction mixture is less than 7.
28. The process of claim 4 wherein the reaction is conducted essentially free of added base.