Lignin extraction with volatile trialkylamines

Patent metadata

Field	Value
Publication number	US-12202852-B2
Application number	US-201917296605-A
Country	US
Kind code	B2
Filing date	Nov 26, 2019
Priority date	Nov 26, 2018
Publication date	Jan 21, 2025
Grant date	Jan 21, 2025

Abstract

The disclosure relates to methods for extracting lignin from lignocellulosic biomass using volatile trialkylamines. A lignocellulosic biomass is combined with an aqueous extraction solution including the trialkylamine and water to provide a biomass extraction mixture that can at least partially extract lignin from the lignocellulosic biomass. The method further includes removing the trialkylamine from the biomass extraction mixture. The method further relates to the utilization of the resulting materials. For example, the lignin extract can be used to make carbon fibers, carbon-carbon materials, or polyamines. The delignified biomass can be used as feed for animals, fungi and/or bacteria. Also, the cellulosic or carbohydrate components of the delignified biomass can be hydrolyzed into pentoses and/or hexoses, which can be used as a feed or starting material for the subsequent conversion into other products. Acetic acid, removed from the biomass in form of trialkylammonium acetate, can be recovered from the mixture for further use or conversion into other chemicals.

First claim

What is claimed is:

1. A method of extracting lignin from a lignocellulosic biomass, the method comprising:
admixing a lignocellulosic biomass with an aqueous extraction solution comprising water and a trialkylamine under temperature and pressure sufficient to extract lignin from the lignocellulosic biomass, thereby providing a biomass extraction mixture comprising the water, the trialkylamine, and the lignin solubilized therein, wherein the aqueous extraction solution contains not more than 0.2 wt % of any additional organic solvents other than one or more trialkylamines; and
removing the trialkylamine from the biomass extraction mixture, thereby forming a solubilized lignin extract;
wherein the trialkylamine has a structure of formula (I) and is present in the aqueous extraction solution in an amount ranging from about 20 wt % to about 80 wt %, based on the total weight of the aqueous extraction solution:

wherein each of R 1 , R 2 , and R 3 is independently C 1-6 alkyl.

2. The method of claim 1 , wherein removing the trialkylamine from the biomass extraction mixture comprises performing one or more of solvent evaporation and distillation.

3. The method of claim 1 , wherein each of R 1 , R 2 , and R 3 is independently methyl, ethyl, propyl, or isopropyl.

4. The method of claim 1 , wherein the trialkylamine is selected from the group consisting of trimethylamine, triethylamine, dimethylethylamine, tripropylamine, and combinations thereof.

5. The method of claim 1 , wherein the water is present in the aqueous extraction solution in an amount ranging from about 20 wt % to about 99 wt %, based on the total weight of the aqueous extraction solution.

6. The method of claim 1 , comprising performing the admixing at a temperature in a range from about 100° C. to about 200° C.

7. The method of claim 1 , comprising performing the admixing in a pressurized vessel.

8. The method of claim 1 , comprising performing the admixing for up to about 20 hours.

9. The method of claim 1 , wherein the lignin is present in the lignin extract in an amount ranging from about 20 wt % to about 60 wt %, based on the total weight of the lignin extract.

10. The method of claim 1 , wherein the lignin extract is substantially free of the trialkylamine.

11. The method of claim 1 , wherein the lignin extract comprises at least about 50% of the lignin initially present in the lignocellulosic biomass.

12. The method of claim 1 , further comprising rinsing the lignin extract with ammonium hydroxide.

13. The method of claim 1 , wherein:
the biomass extraction mixture comprises acetic acid; and
the method further comprises recovering and optionally further processing the acetic acid.

14. The method of claim 1 , wherein the aqueous extraction solution is substantially free of ammonia.

15. The method of claim 1 , wherein the aqueous extraction solution is substantially free of a sulfur component.

16. The method of claim 1 , wherein the biomass extraction mixture is substantially free of additional organic solvents.

17. The method of claim 1 , wherein the biomass extraction mixture is substantially free of ammonia.

18. The method of claim 1 , wherein the biomass extraction mixture is substantially free of a sulfur component.

19. The method of claim 1 , wherein the lignocellulosic biomass is a wood-based biomass.

20. The method of claim 1 , wherein the lignocellulosic biomass comprises poplar.

21. The method of claim 1 , further comprising admixing a second lignocellulosic biomass with a second aqueous extraction solution comprising water and the removed trialkylamine under temperature and pressure sufficient to extract lignin from the second lignocellulosic biomass, thereby providing a second biomass extraction mixture comprising the water, the removed trialkylamine, and the lignin.

22. The method of claim 1 , further comprising:
separating extracted lignocellulosic biomass from the biomass extraction mixture.

23. The method of claim 1 , comprising performing the method batchwise or continuously.

24. The method of claim 1 , further comprising:
themolyzing the lignin extract to provide a carbon material.

25. A method for enzymatic hydrolysis of at least one of cellulose and hemicellulose, the method comprising:
providing a lignin extract and extracted lignocellulosic biomass formed by the method of claim 1 , wherein the lignin extract and the extracted lignocellulosic biomass are substantially free from acetamide, and the extracted lignocellulosic biomass comprises at least one of cellulose and hemicellulose; and
treating the extracted lignocellulosic biomass with an enzyme.

26. The method of claim 1 , wherein the aqueous extraction solution comprises:
from 20 wt % to 50 wt % water, and
from 50 wt % to 80 wt % the trialkylamine.

27. The method of claim 26 , wherein:
the aqueous extraction solution comprises the trialkylamine and the water in a total amount of at least about 99.9 wt %, based on the total weight of the aqueous extraction solution.

28. The method of claim 26 , wherein:
a weight ratio of (i) a combined amount of the trialkylamine and the water in the aqueous extraction solution relative to (ii) an amount of biomass in the biomass extraction mixture is at least 2.

29. A method of extracting lignin from a lignocellulosic biomass, the method comprising:
admixing a lignocellulosic biomass with an aqueous extraction solution comprising water and a trialkylamine at a temperature ranging from about 100° C. to about 200° C. and a sufficient pressure to extract lignin from the lignocellulosic biomass, thereby providing a biomass extraction mixture comprising the water, the trialkylamine, and the lignin solubilized therein, wherein the aqueous extraction solution contains not more than 0.2 wt % of any additional organic solvents other than one or more trialkylamines, and
removing the trialkylamine from the biomass extraction mixture, thereby forming a solubilized lignin extract,
wherein the aqueous extraction solution comprises:
from about 20 wt % to about 80 wt % water, and
from about 20 wt % to about 80 wt % trialkylamine, wherein the trialkylamine is selected from the group consisting of trimethylamine, triethylamine, tripropylamine, dimethylethylamine, and any combination thereof.

Assignees

• Univ Michigan State

Inventors

• Redko Mikhail
• Jackson James E
• Saffron Christopher M
• Lacivita Leo

Classifications

• C08H8/00

  Macromolecular compounds derived from lignocellulosic materials {(pretreatment thereof B27N)} · CPC title

• C08B1/00

  Preparatory treatment of cellulose for making derivatives thereof {, e.g. pre-treatment, pre-soaking, activation} · CPC title

• A23K20/163

  Sugars; Polysaccharides · CPC title

• C08L97/005

  Lignin · CPC title

• Y02E50/30

  Fuel from waste, e.g. synthetic alcohol or diesel · CPC title