Selective oxidation of propane to propylene oxide

Abstract

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.

The embodiment of the invention in which an exclusive property or privilege is claimed is defined as follows: 
     
       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.