Selective oxidation of propane to propylene oxide
The invention provides a one pot method for generating propylene oxide, the method having the steps of contacting propane with catalyst clusters no greater than 30 atoms in the presence of oxygen for a time sufficient to directly convert the propane to the propylene oxide. The invented method eliminates the generation of intermediate compounds or intermediate reaction steps.
1. A one pot method for generating propylene oxide, the method comprising:
a) depositing a plurality of catalyst clusters onto a substrate, wherein the deposited clusters comprise no more than 30 atoms of metal and contain no oxide;
b) contacting propane with the catalyst clusters in the presence of oxygen to convert the propane to the propylene oxide.
2. The method as recited in claim 1 wherein the metal is selected from the group consisting of copper, palladium, platinum, silver, gold, cobalt, and combinations thereof.
3. The method as recited in claim 1 wherein the catalysts are rigidly positioned, relative to each other.
4. The method as recited in claim 1 wherein the substrate is a rigid substrate.
5. The method as recited in claim 4 wherein the rigid substrate is a metal oxide selected from the group consisting of aluminum oxide, iron-oxide, silica oxide, zeolites, titanium oxide, zinc oxide, zirconium oxide, tin oxide, magnesium oxide, cerium oxide and combinations thereof.
6. The method as recited in claim 1 wherein substrate is loose aggregate.
7. The method as recited in claim 1 wherein the method is conducted in a closed reaction vessel and the propane and oxygen are entrained in a carrier gas flowing through the vessel.
8. The method as recited in claim 7 wherein the carrier gas is a relatively inert gas selected from the group consisting of nitrogen, argon, helium, and combinations thereof.
9. The method as recited in claim 1 wherein the method is conducted at ambient pressure.
10. The method as recited in claim 1 wherein the method is conducted at pressures ranging from between about 0.01 atm and 20 atm.
11. The method as recited in claim 1 wherein the method is conducted at temperatures between about 25° C. and 400° C.
12. The method as recited in claim 1 wherein the selectivity for propylene oxide is at least 50 percent at reaction temperatures of between about 25° C. and 400° C.
13. The method as recited in claim 1 wherein the catalyst comprises copper and the clusters contain between 1 and 30 atoms.
14. The method as recited in claim 6 wherein the aggregate is fluidized.
15. The method as recited in claim 1 wherein propylene oxide is generated from propane without any intermediate reaction steps.
16. The method as recited in claim 1 wherein propylene oxide is generated from propane without the production of intermediates.
17. The method as recited in claim 4 wherein the rigid substrate is a carbon based support selected from the group consisting of nanocrystalline diamond, graphite, amorphous carbon, graphene, and combinations thereof.
18. The method as recited in claim 1 wherein the clusters further comprise undercoordinated active sites.
19. The method as recited in claim 1 wherein the clusters are deposited as neat metal.