Processes for fractionation of biomass
View Patent ↗Disclosed herein are systems and methods delignifying and depolymerizing lignocellulosic biomass into an aromatic species-rich fraction and a carbohydrate-rich fraction. The resultant fractions can be used as raw materials to produce value-added goods from biogenic carbon.
1 . A method of processing biomass comprising heating a mixture comprising biomass and a solvent comprising a compound of Formula (1):
wherein
R 1 is selected from C 1-8 alkyl, C 3-8 cycloalkyl, aryl, or C 1-8 heteroaryl optionally substituted one or more times by F, Cl, Br, C 1-8 alkoxy, C 3-8 cycloalkyl, aryl, C 1-8 heterocyclyl, or C 1-8 heteroaryl;
R 3 is selected from H, C 1-8 alkyl, C 3-8 cycloalkyl, aryl, or C 1-8 heteroaryl optionally substituted one or more times by F, Cl, Br, C 1-8 alkoxy, C 3-8 cycloalkyl, aryl, C 1-8 heterocyclyl, or C 1-8 heteroaryl;
R 2 and R 2* together form an oxo, or
R 2* is H and R 2 is OR 2a wherein R 2a is selected from H, C 1-8 alkyl, C 3-8 cycloalkyl, aryl, or C 1-8 heteroaryl optionally substituted one or more times by F, Cl, Br, C 1-8 alkoxy, C 3-8 cycloalkyl, aryl, C 1-8 heterocyclyl, or C 1-8 heteroaryl, wherein the mixture further comprises a homogeneous catalyst, a heterogeneous catalyst, or a combination thereof.
2 . The method according to claim 1 , wherein R 2a and R 2* are H, and R 1 and R 3 are independently selected from methyl, ethyl, isopropyl, 2-methoxyethyl.
3 . The method according to claim 1 , wherein R 2* is H, and R 1 , R 2a , and R 3 are independently selected from methyl, ethyl, isopropyl, 2-methoxyethyl.
4 . The method according to claim 1 , wherein R 2 and R 2* together form an oxo, and R 1 and R 3 are independently selected from methyl, ethyl, isopropyl, 2-methoxyethyl.
5 . The method according to claim 1 , wherein the mixture further comprises water, C 1-4 alcohol, or a combination thereof.
6 . The method according to claim 1 , wherein the heating comprises heating the mixture to a temperature from 75-250° C.
7 . The method according to claim 1 , wherein the homogeneous catalyst comprises an acid.
8 . The method according to claim 7 , wherein R 2a and R 2* are H, and the heterogeneous catalyst comprises Pd/C, Pt/C, Ru/C, Ni/C, Ni/alumina, Pd/alumina, Pt/alumina, Ru/alumina, Raney nickel, Raney cobalt, Fe 2 S, a zeolite, or a combination thereof.
9 . The method according to claim 8 , wherein the heterogeneous catalyst is present in an amount from 1-10 wt. %, relative to the mass of the biomass.
10 . The method according to claim 1 , further comprising separating the solvent from residual solids to provide a liquid comprising lignin compounds.
11 . The method according to claim 10 , wherein the residual solids comprise cellulose in an amount of at least 90% by mass.
12 . The method according to claim 10 , wherein separating the solvent from residual solids comprises filtering the mixture.
13 . The method according to claim 10 , wherein the lignin compounds are separated from the solvent by precipitation.
14 . The method according to claim 1 , wherein the biomass comprises a vegetative species.
15 . The method according to claim 14 , wherein the biomass comprises a woody plant.