Methods of producing alkylfurans
Provided herein are methods of producing dialkylfurans, such as 2,5-dimethylfuran, and other alkyl furans, such as 2-methylfuran. For example, 2,5-dimethylfuran may be produced by reducing (5-methylfuran-2-yl)methanol or 2-(chloromethyl)-5-methylfuran.
1. A method of producing 5-methylfuran-2-carbaldehyde, the method comprising:
(i) providing 5-(chloromethyl)furfural; and
(ii) converting the 5-(chloromethyl)furfural to 5-methylfuran-2-carbaldehyde in the presence of
hydrogen,
a catalyst, wherein the catalyst comprises Pd/C, Pd/Al 2 O 3 , or PdCl 2 , and
an amide reagent, or a urea reagent, or a combination thereof,
wherein the amide reagent is N,N-dimethylformamide; or
wherein the urea reagent is a reagent of formula (ii):
wherein:
(A) each R a , R b , R c and R d is independently H, aliphatic, aryl or heteroaryl; or
(B) R a and R b are taken together with the nitrogen atoms to which they are connected to form a cyclic moiety having at least 3 ring atoms; and each R c and R d is independently H, aliphatic, aryl or heteroaryl; or
(C) each R a and R b is independently H, aliphatic, aryl or heteroaryl; and R c and R d are taken together with the nitrogen atoms to which they are connected to form a cyclic moiety having at least 3 ring atoms; or
(D) R a and R b are taken together with the nitrogen atoms to which they are connected to form a cyclic moiety having at least 3 ring atoms; and R c and R d are taken together with the nitrogen atoms to which they are connected to form a cyclic moiety having at least 3 ring atoms; or
(E) each R a and R c is independently H, aliphatic, aryl or heteroaryl; and R b and R d are taken together with the nitrogen atoms to which they are connected to form a cyclic moiety having at least 5 ring atoms; or
(F) each R b and R d is independently H, aliphatic, aryl or heteroaryl; and R a and R c are taken together with the nitrogen atoms to which they are connected to form a cyclic moiety having at least 5 ring atoms, or
wherein the urea reagent is a reagent of formula (iii):
wherein:
each R a and R c is independently H, aliphatic, aryl or heteroaryl; and
t is an integer greater than or equal to 0.
2. The method of claim 1 , wherein the urea reagent is
or any combination thereof.
3. The method of claim 1 , wherein the urea reagent is
or any combination thereof.
4. The method of claim 1 , further comprising converting the 5-(chloromethyl)furfural to 5-methylfuran-2-carbaldehyde in the presence of an aromatic reagent.
5. The method of claim 4 , wherein the aromatic reagent comprises at least one mono-aryl compound, at least one di-aryl compound, or at least one tri-aryl compound, or any mixtures thereof.
6. The method of claim 5 , wherein the at least one mono-aryl compound is toluene, or para-xylene, or any combination thereof.
7. The method of claim 1 , further comprising isolating the 5-methylfuran-2-carbaldehyde.
8. A method, comprising:
producing 5-methylfuran-2-carbaldehyde according to the method of claim 1 ;
isolating the 5-methylfuran-2-carbaldehyde;
reacting the isolated 5-methylfuran-2-carbaldehyde with acid in the presence of hydrogen and a metal catalyst to produce (5-methylfuran-2-yl)methanol; and
reducing the (5-methylfuran-2-yl)methanol to produce 2,5-dimethylfuran.