Biorefining compounds and organocatalytic upgrading methods
View Patent ↗The invention provides new methods for the direct umpolung self-condensation of 5-hydroxymethylfurfural (HMF) by organocatalysis, thereby upgrading the readily available substrate into 5,5′-di(hydroxymethyl)furoin (DHMF). While many efficient catalyst systems have been developed for conversion of plant biomass resources into HMF, the invention now provides methods to convert such nonfood biomass directly into DHMF by a simple process as described herein. The invention also provides highly effective new methods for upgrading other biomass furaldehydes and related compound to liquid fuels. The methods include the organocatalytic self-condensation (umpolung) of biomass furaldehydes into (C 8 -C 12 )furoin intermediates, followed by hydrogenation, etherification or esterification into oxygenated biodiesel, or hydrodeoxygenation by metal-acid tandem catalysis into premium hydrocarbon fuels.
1. An organocatalytic method comprising homocoupling 5-hydroxymethylfurfural (HMF), the method comprising contacting HMF and an ionic liquid under conditions wherein the ionic liquid forms an N-heterocyclic carbene (NHC), or by contacting HMF and a discrete NHC, to provide 5,5′-di(hydroxymethyl)furoin (DHMF), and further comprising hydrogenation, hydrogenolysis, hydrodeoxygenation, etherification, or esterification, or combinations thereof, of the DHMF to provide a liquid fuel.
2. The method of claim 1 wherein the liquid fuel comprises a compound of Formula I:
wherein each R 1 is independently H, OH, halo, amine, alkylamino, dialkylamino, alkoxy, or acyloxy; and R 2 is OH, halo, amine, alkylamino, dialkylamino, alkoxy, or acyloxy.
3. The method of claim 2 wherein the compound of Formula I is:
wherein each R is independently aryl or (C 1 -C 12 )alkyl.
4. The method of claim 2 wherein the compound of Formula I is:
5. The method of claim 1 wherein the method comprises hydrodeoxygenation and the liquid fuel comprises decane, undecane, dodecane, or a combination thereof.