Aromatization or dehydrocyclization of N-alkanes using soluble transition metal complexes
The invention provides methods and compositions useful for synthesizing alkylaromatics from an n-alkanes.
1. A method of synthesizing an alkylaromatic hydrocarbon from an n-alkane comprising the step of contacting the n-alkane with a pincer-ligated iridium catalyst wherein the pincer-ligated iridium catalyst is selected from:
(a) ( R PCP)Ir:
wherein each R is independently alkyl, and each X is independently CH 2 or O;
(b) ( R PCP)Ir:
wherein R is i-Pr or other alkyl, and each X is independently CH 2 or O;
(c) ( iPr PCP)IrH n , wherein n is 2 or 4;
(d) ( iPr PCP)IrH 4 ; and
(e)
wherein each R is independently alkyl.
2. The method of claim 1 , wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst is performed at a temperature above 175° C.
3. The method of claim 1 , wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst is performed at a temperature of from about 150° C. to about 175° C.
4. The method of claim 1 , wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst is performed at a temperature of about 165° C.
5. The method of claim 1 , wherein the pincer-ligated iridium catalyst is ( R PCP)Ir:
wherein each R is independently alkyl, and each X is independently CH 2 or O.
6. The method of claim 1 , wherein the pincer-ligated iridium catalyst is ( R PCP)Ir:
wherein R is i-Pr or other alkyl, and each X is independently CH 2 or O.
7. The method of claim 1 , wherein the pincer-ligated iridium catalyst is ( iPr PCP)IrH n , wherein n is 2 or 4.
8. The method of claim 1 , wherein the pincer-ligated iridium catalyst is ( iPr PCP)IrH 4 .
9. The method of claim 1 , wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst is performed in the presence of a H-acceptor.
10. The method of claim 9 , wherein the H-acceptor is t-butylethylene (TBE), propylene or ethylene.
11. The method of claim 1 wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst comprises refluxing or a physical method to remove hydrogen.
12. The method of claim 1 , wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst comprises the use of a hydrogen sponge or a hydrogen-permeable membrane.
13. The method of claim 12 , wherein the hydrogen sponge comprises a metal-organic-framework, a palladium metal or metal alloy, or a crystalline pincer complex.
14. The method of claim 1 , wherein the n-alkane is a C 6 -C 30 n-alkane.
15. The method of claim 1 , wherein the n-alkane is n-hexane (C 6 ), n-octane (C 8 ), n-decane (C 10 ) or n-dodecane (C 12 ).
16. The method of claim 1 , wherein the step of contacting the n-alkane with the pincer-ligated iridium catalyst comprises a use of a cyclization co-catalyst.
17. The method of claim 16 , wherein the cyclization co-catalyst is a Lewis acid catalyst.
18. The method of claim 1 , further comprising identifying a product(s) of the synthesizing the alkylaromatic hydrocarbon.
19. The method of claim 1 , further comprising separating a product(s) of the synthesizing the alkylaromatic hydrocarbon.
20. The method of claim 1 , wherein the pincer-ligated iridium catalyst is:
wherein each R is independently alkyl.
21. The method of claim 1 wherein the pincer-ligated iridium catalyst is a soluble pincer-ligated iridium catalyst.