Reduction catalysts
Disclosed are catalysts comprised of platinum and rhodium on a support selected from the group of zirconia, stabilized (doped) zirconia, zirconia-metal oxide composites, and mixtures thereof, wherein the outer surfaces of the support are selected from the group of zirconia, stabilized zirconia, and mixtures thereof. More particularly, the supported catalysts comprise platinum and rhodium, wherein the molar ratio of platinum to rhodium is in the range of about 3:1 to about 1:2. The average pore diameter of the catalyst supports is in the range of about 5 nm to about 70 nm and the surface area is in the range of about 15 m 2 /g to about 200 m 2 /g. Also disclosed are methods for the hydrodeoxygenation of carboxylic acids, mono- and/or di-lactones thereof having at least one hydroxyl group on the backbone thereof to corresponding acids where the backbone hydroxyl group has been reduced in the presence of the catalyst.
1. A heterogeneous catalyst comprising platinum and rhodium on a support selected from the group consisting of a zirconia support comprised of zirconia and no more than about 5 wt % of other materials, a stabilized (doped) zirconia support comprised of zirconia and between about 1 wt % and about 40 wt % of dopants, and mixtures thereof, wherein: (a) the molar ratio of platinum to rhodium is in the range of from about 3:1 to about 1:2, (b) platinum is present in an amount in the range of from about 0.4 wt % to about 1.4 wt %, (c) rhodium is present in an amount in the range of from about 0.1 Wt % to about 0.8 wt %, and (d) the average pore diameter of the support is in the range of from about 5 nm to about 70 nm.
2. The catalyst of claim 1 , wherein the surface area of the catalyst is equal to or less than about 60 m 2 /g.
3. The catalyst of claim 1 , wherein the surface area of the support is in the range of between about 15 m 2 /g and about 125 m 2 /g.
4. The catalyst of claim 3 , wherein the support is the zirconia support comprised of zirconia and no more than about 5 wt % of other materials.
5. The catalyst of claim 3 , wherein the catalyst further comprises a metal selected from the group of palladium, molybdenum and tungsten.
6. The catalyst of claim 1 , wherein at least a portion of the platinum is present as Pt(0).
7. The catalyst of claim 6 , wherein at least a portion of the rhodium is present as Rh(0).
8. The catalyst of claim 1 , wherein the catalyst further comprises a metal selected from the group of palladium, molybdenum and tungsten.
9. The catalyst of claim 1 , wherein the support is the zirconia support comprised of zirconia and no more than about 5 wt % of other materials.
10. The catalyst of claim 1 , wherein the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 20 nm.
11. A process for producing an adipic acid product comprising reacting a substrate of formula I or a mono- or di-lactone thereof:
where each “X” is, independently, selected from the group of hydroxyl, oxo, halo, acyloxy and hydrogen provided that at least one X is not hydrogen, and each “R” is, independently, selected from the group of salt-forming ions, hydrogen and hydrocarbyl or substituted hydrocarbyl, with hydrogen in the presence of the heterogeneous catalyst of claim 3 , to convert the substrate to the adipic acid product of formula II
where R is as defined above for formula I.
12. The process of claim 11 , wherein the support is the zirconia support comprised of zirconia and no more than about 5 wt % of other materials.
13. The process of claim 11 , wherein the average pore diameter of the support is in the range of from about 5 nm to about 40 nm.
14. The process of claim 11 , wherein the surface area of the support is in the range of between about 15 m 2 /g and about 125 m 2 /g.
15. The process of claim 11 , wherein at least a portion of the platinum is present as Pt(0).
16. The process of claim 15 , wherein at least a portion of the rhodium is present as Rh(0).
17. The process of claim 11 , wherein the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 30 nm.
18. process of claim 11 , wherein the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 20 nm.
19. The process of claim 11 , wherein the yield of adipic acid is at least 80%.
20. The process of claim 11 , wherein the adipic acid product comprises adipic acid.
21. The process of claim 11 , wherein each “R” is independently hydrogen, a salt forming ion, or an unsubstituted hydrocarbyl having from 1 to 18 carbon atoms.
22. The process of claim 21 , wherein each “R” is independently hydrogen or a salt forming ion selected from the group consisting of ammonium ions, alkali metal ions, and alkaline earth metal ions.
23. The process of claim 22 , wherein each “X” is hydroxyl.
24. The process of claim 23 , wherein the substrate of formula I or mono- or di-lactone thereof is reacted with hydrogen in the presence of the catalyst and a halogen source.
25. The process of claim 24 , wherein the halogen source comprises as hydrohalic acid.
26. A heterogeneous catalyst comprising platinum and rhodium on a support selected from the group consisting of a zirconia support comprised of zirconia and no more than about 5 wt % of other materials, a stabilized (doped) zirconia support comprised of zirconia and between about 1 wt % and about 40 wt % of dopants, and mixtures thereof, wherein: (a) the molar ratio of platinum to rhodium is in the range of from about 3:1 to about 1:2, (b) platinum is present in an amount in the range of from about 0.4 wt % to about 1.4 wt %, (c) rhodium is present in an amount in the range of from about 0.1 wt % to about 0.8 wt %, and (d) the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 30 nm.
27. The catalyst of claim 26 , wherein the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 20 nm.
28. The catalyst of claim 26 , wherein the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 12 nm.
29. The catalyst of claim 26 , wherein the support is the zirconia support comprised of zirconia and no more than about 5 wt % of other materials.
30. The catalyst of claim 26 , wherein the surface area of the catalyst is equal to or less than about 60 m 2 /g.
31. The catalyst of claim 26 , wherein the surface area of the support is in the range of between about 15 m 2 /g and about 125 m 2 /g.
32. The catalyst of claim 26 , wherein the average pore diameter of the support is in the range of from about 5nm to about 70 nm.
33. The catalyst of claim 26 , wherein the catalyst further comprises a metal selected from the group of palladium, molybdenum and tungsten.
34. A process for producing an adipic acid product comprising reacting a substrate of formula I or a mono- or di-lactone thereof:
where each “X” is, independently, selected from the group of hydroxyl, oxo, halo, acyloxy and hydrogen provided that at least one X is not hydrogen, and each “R” is, independently, selected from the group of salt-forming ions, hydrogen and hydrocarbyl or substituted hydrocarbyl, with hydrogen in the presence of the heterogeneous catalyst of claim 9 , to convert the substrate to the adipic acid product of formula II
where R is as defined above for formula I.
35. The process of claim 34 , wherein the support is the zirconia support comprised of zirconia and no more than about 5 wt % of other materials.
36. The process of claim 34 , wherein the average pore diameter of the support is in the range of from about 5 nm to about 70 nm.
37. The process of claim 34 , wherein the surface area of the support is in the range of between about 15 m 2 /g and about 125 m 2 /g.
38. The process of claim 34 , wherein at least a portion of the platinum is present as Pt(0).
39. The process of claim 38 , wherein at least a portion of the rhodium is present as Rh(0).
40. The process of claim 34 , wherein the particle sizes of the platinum and rhodium metals are substantially in the range of from about 2 nm to about 20 nm.
41. The process of claim 34 , wherein the yield of adipic acid is at least 80%.
42. The process of claim 34 , wherein the adipic acid product comprises adipic acid.
43. The process of claim 34 , wherein each “R” is independently hydrogen, a salt forming ion, or an unsubstituted hydrocarbyl having from 1 to 18 carbon atoms.
44. The process of claim 43 , wherein each “R” is independently hydrogen or a salt forming ion selected from the group consisting of ammonium ions, alkali metal ions, and alkaline earth metal ions.
45. The process of claim 44 , wherein each “X” is hydroxyl.
46. The process of claim 45 , wherein the substrate of formula I or mono- or di-lactone thereof is reacted with hydrogen in the presence of the catalyst and a halogen source.
47. The process of claim 46 , wherein the halogen source comprises as hydrohalic acid.