Compositions and methods for the dissolution and depolymerization of lignin
The present invention provides for a method for dissolving and/or depolymerizing lignin comprising: (a) providing a composition comprising lignin, (b) contacting the composition with a strong hydrogen donor, such as a polyol, to form a first solution, (c) incubating the first solution at a temperature equal to or less than 100° C., whereby at least 20% by weight of the lignin is dissolved, (d) optionally introducing an oxidation agent to the first solution to form a second solution, wherein the temperature of the second solution is equal to or less than 100° C., whereby lignin is depolymerized, and (e) optionally introducing an anti-solvent to the second solution to precipitate the depolymerized lignin.
1. A method for dissolving and depolymerizing lignin comprising: (a) providing a composition comprising lignin, (b) contacting the composition with a strong hydrogen donor and an ionic liquid (IL) to form a first solution, (c) incubating the first solution at a temperature less than 80° C., whereby at least 20% by weight of the lignin is dissolved, (d) introducing an oxidation agent to the first solution to form a second solution, wherein the temperature of the second solution is equal to or less than 100° C., whereby lignin is at least partly or wholly depolymerized, and (e) optionally introducing an anti-solvent to the second solution to precipitate the depolymerized lignin.
2. The method of claim 1 , wherein the composition is a biomass comprising lignin.
3. The method of claim 1 , wherein the composition of step (a) comprises a high solid loading whereby the composition comprises equal to or more than 10% by weight of a solid comprising the lignin.
4. The method of claim 1 , wherein the strong hydrogen donor is a polyol.
5. The method of claim 4 , wherein the polyol is an alkyl polyol.
6. The method of claim 5 , wherein the alkyl polyol has an alkyl chain of 10 or fewer carbon atoms.
7. The method of claim 5 , wherein the alkyl polyol is ethylene glycol (EG), propylene glycol, or glycerin (glycerol).
8. The method of claim 1 , wherein the second solution has, or is incubated at, a temperature of equal to or less than 90° C.
9. The method of claim 8 , wherein the second solution has, or is incubated at, a temperature of equal to or less than 80° C.
10. The method of claim 9 , wherein the first solution and the second solution each have, or is incubated at, a temperature of equal to or less than 80° C. and more than 20° C.
11. The method of claim 10 , wherein the first solution and the second solution each have, or is incubated at, a temperature of equal to or less than 70° C. and more than 20° C.
12. The method of claim 1 , wherein step (c) results in the dissolution of at least 25% by weight of the lignin.
13. The method of claim 1 , wherein the oxidation agent is hydrogen peroxide, HNO 3 , Br 2 , IO 3 − , CrO 4 − , Pt 2+ , MnO 2 , O 2 , Cr 2 O 7 2− , Cl 2 (g), PbO 2 , MnO 4 − , Co 3+ , S 2 O 8 2− , O 3 (g), or F 2 (g).
14. The method of claim 1 , wherein the method comprises (e) introducing an anti-solvent to the second solution to precipitate the depolymerized lignin.
15. The method of claim 14 , wherein the anti-solvent is ethanol or isopropanol.