Modified sulfuric acid and uses thereof
One-pot processes to separate lignin from a lignocellulosic feedstock include providing a vessel; providing a lignocellulosic feedstock; providing an aqueous composition comprising an acid, a modifying agent comprising a substituted aromatic compound, and a peroxide; and exposing the lignocellulosic feedstock to the composition in the vessel for a period of time sufficient to remove at least 80% of the lignin present in the lignocellulosic feedstock.
1. A one-pot process to separate lignin from a lignocellulosic feedstock, said process comprising:
providing a vessel;
providing a lignocellulosic feedstock;
providing an aqueous composition comprising:
sulfuric acid;
a modifying agent comprising a substituted aromatic compound; and
a peroxide; and
exposing the lignocellulosic feedstock to the composition in the vessel for a period of time sufficient to remove at least 80% of the lignin present in the lignocellulosic feedstock.
2. The process of claim 1 , further comprising separating a liquid phase comprising dissolved lignin fragments from a solid phase comprising cellulose fibres.
3. The process of claim 1 , wherein the peroxide is hydrogen peroxide.
4. The process of claim 1 , wherein the period of time is sufficient to remove at least 90% of the lignin present in the lignocellulosic feedstock.
5. The process of claim 1 , wherein the period of time is sufficient to remove at least 95% of the lignin present in the lignocellulosic feedstock.
6. The process of claim 1 , wherein the temperature of the aqueous composition prior to exposing it to the lignocellulosic feedstock is below 50° C.
7. The process of claim 1 , wherein the temperature of the aqueous composition prior to exposing it to the lignocellulosic feedstock is below 40° C.
8. The process of claim 1 , wherein the temperature of the aqueous composition prior to exposing it to the lignocellulosic feedstock is below 30° C.
9. The process of claim 1 , wherein the process is carried out at ambient temperature and/or ambient pressure.
10. The process of claim 1 , wherein the sulfuric acid and the substituted aromatic compound are present in a molar ratio ranging from 28:1 to 2:1.
11. The process of claim 1 , wherein the sulfuric acid and the substituted aromatic compound are present in a molar ratio ranging from 20:1 to 4:1.
12. The process of claim 1 , wherein the sulfuric acid is 20 to 80 wt % of the aqueous composition.
13. The process of claim 1 , wherein the sulfuric acid is 30 to 70 wt % of the aqueous composition.
14. The process of claim 1 , wherein the composition as a pH less than 1.
15. The process of claim 1 , wherein the substituted aromatic compound has a molecular weight below 300 g/mol.
16. The process of claim 1 , wherein the substituted aromatic compound is a secondary amine.
17. The process of claim 1 , where the substituted aromatic compound is selected from the group consisting of sulfanilic acid, metanilic acid, orthanilic acid, and combinations thereof.
18. The process of claim 10 , where the substituted aromatic compound is selected from the group consisting of sulfanilic acid, metanilic acid, orthanilic acid, and combinations thereof.