Cycloalkane oxidation catalysts and method to produce alcohols and ketones
The present invention concerns a method of oxidizing a cycloalkane to form a product mixture containing a corresponding alcohol and ketone, said method comprising contacting a cycloalkane with a hydroperoxide compound in the presence of a catalytic effective amount of a cerium oxide based catalyst.
1. A method of oxidizing a cycloalkane to form a product mixture containing a corresponding alcohol and ketone, said method comprising contacting a cycloalkane with a cyclohexyl hydroperoxide compound in the presence of at least a cerium oxide based catalyst that has a cerium oxide content of at least 60 wt %, wherein the cerium oxide based catalyst is at least one catalyst selected from the group consisting of:
a composition comprising cerium oxide and at least one oxide of another rare earth,
a composition comprising cerium oxide and at least one compound of another rare earth,
a cerium composite oxide comprising at least cerium oxide, silicon oxide, titanium oxide and at least one oxide of another rare earth, and/or
a composition comprising cerium oxide, zirconium oxide and at least one oxide of another rare earth; and
wherein the cerium oxide based catalyst at least includes an oxide of a rare earth of one of praseodymium oxide and/or lanthanum oxide,
wherein the cerium oxide based catalyst is used as such.
2. A method according to claim 1 , wherein cycloalkane is selected from the group consisting of cyclopentane, cyclohexane, cycloheptane, and cyclooctane.
3. A method according to claim 2 , wherein the cycloalkane is cyclohexane, the alcohol is cyclohexanol and the ketone is cyclohexanone.
4. A method according to claim 1 , wherein the amount of catalyst is from 0.01 wt % to 10 wt. based on the total weight of the reaction medium.
5. A method to produce adipic acid, comprising:
oxidizing liquid cyclohexane by reaction with oxygen gas to produce cyclohexane hydroperoxide,
decomposing the cyclohexane hydroperoxide into a mixture of cyclohexanol and cyclohexanone, by using the cyclohexane hydroperoxide as the hydroperoxide compound in a method according to claim 1 ,
oxidizing, with nitric acid, the mixture of cyclohexanol and cyclohexanone to adipic acid, and extracting and purifying the adipic acid.
6. A method of producing polyamide, obtained by polycondensation from adipic acid produced by the method of claim 5 , and hexamethylenediamine, comprising the following steps:
mixing adipic acid produced by the method of claim 5 with hexamethylenediamine, to produce hexamethylenediammonium adipate, and
heatingan aqueous solution of the hexamethylenediammonium adipate.
7. The method according to claim 1 , wherein the cerium oxide based catalyst has a nano-rod nanostructure.
8. The method according to claim 1 , wherein the cerium oxide based catalyst is a composition comprising cerium oxide and at least one oxide of another rare earth.
9. The method according to claim 1 , wherein the cerium oxide based catalyst is a composition comprising cerium oxide and at least one compound of another rare earth.
10. The method according to claim 1 , wherein the cerium oxide based catalyst is a cerium composite oxide comprising at least cerium oxide, silicon oxide, titanium oxide and at least one oxide of another rare earth.
11. The method according to claim 1 , wherein the contacting of the cycloalkane with the cyclohexyl hydroperoxide compound in the presence of at least the cerium oxide based catalyst does not include an addition of any additional oxidizing agent selected from group consisting of pure oxygen, air, oxygen-enriched air, oxygen-depleted air, oxygen diluted with an inert gas, or a combination thereof.
12. The method according to claim 11 , wherein the contacting of the cycloalkane with the cyclohexyl hydroperoxide compound in the presence of at least the cerium oxide based catalyst is conducted in the presence of a nitrogen overpressure.