Chromium-catalyzed production of alcohols from hydrocarbons
Processes for converting a hydrocarbon reactant into an alcohol compound and/or a carbonyl compound are disclosed, and these processes include the steps of irradiating the hydrocarbon reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state with a light beam at a wavelength in the UV-visible spectrum to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst, and hydrolyzing the reduced chromium catalyst to form a reaction product comprising the alcohol compound and/or the carbonyl compound. In addition, these processes can further comprise a step of calcining all or a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
1. A process for converting a hydrocarbon reactant into an alcohol compound and/or a carbonyl compound, the process comprising:
(i) irradiating the hydrocarbon reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state with a light beam comprising wavelengths above 350 nm and below 500 nm to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst;
(ii) hydrolyzing the reduced chromium catalyst to form a reaction product comprising the alcohol compound and/or the carbonyl compound; and
(iii) separating at least a portion of the hydrocarbon reactant from the reaction product, wherein the at least a portion of the hydrocarbon reactant is recycled and irradiated with the supported chromium catalyst again.
2. The process of claim 1 , wherein the hydrocarbon reactant and the supported chromium catalyst are irradiated with from about 50,000 to about 500,000 lux.
3. The process of claim 1 , wherein the light beam is from a blue light source or a UV light source.
4. The process of claim 1 , wherein the hydrocarbon reactant comprises a C 1 to C 6 alkane compound.
5. The process of claim 1 , wherein the light beam comprises wavelengths above 350 nm and below 450 nm.
6. The process of claim 1 , wherein the supported chromium catalyst contains from about 0.01 to about 50 wt. % of chromium, based on the weight of the supported chromium catalyst.
7. The process of claim 1 , wherein the reduced chromium catalyst contains chromium having an average valence of less than or equal to about 5.25.
8. The process of claim 1 , wherein a molar yield of the alcohol compound and/or the carbonyl compound is from about 0.05 to about 1.8 moles of the alcohol compound and/or the carbonyl compound per mole of chromium (VI) in the supported chromium catalyst.
9. The process of claim 1 , further comprising a step of separating at least a portion of the alcohol compound and/or the carbonyl compound from the reaction product after step (ii).
10. The process of claim 1 , further comprising:
separating at least a portion of the reduced chromium catalyst from the reaction product after step (ii); and
calcining the at least a portion of the reduced chromium catalyst to regenerate the supported chromium catalyst.
11. The process of claim 1 , wherein the hydrocarbon reactant comprises methane and the alcohol compound comprises methanol.
12. The process of claim 1 , wherein the process comprises contacting the hydrocarbon reactant with a fluidized bed of the supported chromium catalyst, and irradiating while contacting.
13. The process of claim 1 , wherein the process comprises contacting the hydrocarbon reactant with a fixed bed of the supported chromium catalyst, and irradiating while contacting.
14. The process of claim 1 , wherein:
hydrolyzing is conducted at a temperature from about 0° C. to about 100° C.; and
hydrolyzing comprises contacting the reduced chromium catalyst with a hydrolysis agent comprising water, steam, an alcohol agent, an acid agent, an alkaline agent, or any combination thereof.
15. The process of claim 1 , wherein the irradiating step is conducted at a temperature from about 0° C. to about 100° C.
16. The process of claim 1 , wherein:
the supported chromium catalyst contains from about 0.1 to about 15 wt. % of chromium, based on the weight of the supported chromium catalyst;
the hydrocarbon reactant comprises a C 1 to C 6 alkane compound; and
the light beam comprises wavelengths above 350 nm and below 450 nm.
17. The process of claim 16 , wherein the C 1 to C 6 alkane compound is methane.
18. A process for converting a hydrocarbon reactant into an alcohol compound and/or a carbonyl compound, the process comprising:
(i) irradiating the hydrocarbon reactant and a supported chromium catalyst comprising chromium in a hexavalent oxidation state with a light beam comprising wavelengths above 350 nm and below 500 nm to reduce at least a portion of the supported chromium catalyst to form a reduced chromium catalyst; and
(ii) hydrolyzing the reduced chromium catalyst to form a reaction product comprising the alcohol compound and/or the carbonyl compound; wherein:
the hydrocarbon reactant and the supported chromium catalyst are irradiated with from about 50,000 to about 500,000 lux; and
the light beam is from a blue light source or a UV light source.
19. The process of claim 18 , wherein the process comprises:
contacting the hydrocarbon reactant with a fluidized bed of the supported chromium catalyst, and irradiating while contacting; or contacting the hydrocarbon reactant with a fixed bed of the supported chromium catalyst, and irradiating while contacting.
20. The process of claim 18 , wherein:
the supported chromium catalyst contains from about 0.1 to about 15 wt. % of chromium, based on the weight of the supported chromium catalyst;
the hydrocarbon reactant comprises a C 1 to C 6 alkane compound; and
the light beam comprises wavelengths above 350 nm and below 450 nm.