Methods for the manufacture of cellulose nanocrystals
View Patent ↗Embodiments of the present invention relates generally to methods and systems for the manufacture of cellulose nanocrystals. In one embodiment, a method for manufacturing cellulose nanocrystals comprises reacting lignocellulosic fibers with sulfuric acid in water, introducing a water-insoluble solvent to substantially terminate the reaction, separating a first stream comprising at least 70% of the unreacted sulfuric acid in the water-insoluble solvent from a second stream comprising a plurality of cellulose nanocrystals and the remainder of the unreacted sulfuric acid in water, and separating the cellulose nanocrystals from the second stream.
1. A method for manufacturing cellulose nanocrystals comprising:
reacting lignocellulosic fibers with sulfuric acid in water;
introducing a water-insoluble solvent to substantially terminate the reaction;
separating a first stream comprising at least 70% of the unreacted sulfuric acid in the water-insoluble solvent from a second stream comprising a plurality of cellulose nanocrystals and the remainder of the unreacted sulfuric acid in water;
recovering the unreacted sulfuric acid in the second stream, wherein said recovering comprises introducing a second water-insoluble solvent to the second stream, separating a third stream comprising the unreacted sulfuric acid and the second water-insoluble solvent from a fourth stream comprising water, and separating the unreacted sulfuric acid from the second water-insoluble solvent; and
separating the cellulose nanocrystals from the second stream.
2. The method of claim 1 , further comprising adding water to the second stream prior to separation of the cellulose nanocrystals.
3. The method of claim 1 , wherein the recovering the unreacted sulfuric acid in the second stream comprises recovering substantially all of the unreacted sulfuric acid in the second stream.
4. The method of claim 3 , wherein recovering substantially all of the unreacted sulfuric acid in the second stream comprises introducing a second water-insoluble solvent to the second stream, separating a third stream comprising substantially all of the unreacted sulfuric acid and the second water-insoluble solvent from a fourth stream comprising water, and separating substantially all of the unreacted sulfuric acid from the second water-insoluble solvent.
5. The method of claim 4 , wherein the second water-insoluble solvent is the same as the first water-insoluble solvent.
6. The method of claim 4 wherein the fourth stream further comprises polysaccharides.
7. The method of claim 4 , wherein separating substantially all of the unreacted sulfuric acid from the second water-insoluble solvent comprises introducing a third water-insoluble solvent to the third stream, separating a fifth stream comprising substantially all of the unreacted sulfuric acid and the third water-insoluble solvent from a sixth stream comprising the second water-insoluble solvent.
8. The method of claim 7 , further comprising separating substantially all of the unreacted sulfuric acid from the third water-insoluble solvent.
9. The method of claim 7 , wherein the third water-insoluble solvent is different from the first water-insoluble solvent and the second water-insoluble solvent.
10. The method of claim 7 , wherein the third water-insoluble solvent has a lower boiling point than the first water-insoluble solvent and the second water-insoluble solvent.
11. The method of claim 1 , further comprising recovering substantially all of the unreacted sulfuric acid in the first stream.
12. The method of claim 11 , wherein recovering substantially all of the unreacted sulfuric acid in the first stream comprises introducing a second water-insoluble solvent to the first stream, separating a fifth stream comprising substantially all of the unreacted sulfuric acid and the second water-insoluble solvent from a sixth stream comprising the first water-insoluble solvent, and separating substantially all of the unreacted sulfuric acid from the second water-insoluble solvent.
13. The method of claim 12 , wherein the second water-insoluble solvent is different from the first water-insoluble solvent.
14. The method of claim 12 , wherein the second water-insoluble solvent has a lower boiling point than the first water-insoluble solvent.
15. The method of claim 1 , wherein the first stream comprises at least 80% of the unreacted sulfuric acid.
16. The method of claim 1 , wherein the second stream further comprises dissolved polysaccharides.
17. A method for manufacturing cellulose nanocrystals comprising:
reacting lignocellulosic fibers with sulfuric acid in water;
introducing a water-insoluble solvent to the solution to substantially terminate the reaction;
separating a first stream comprising at least 70% of the unreacted sulfuric acid in the water-insoluble solvent from a second stream comprising a plurality of cellulose nanocrystals and the remainder of the unreacted sulfuric acid in water;
adjusting the pH of the second stream to greater than about 1;
separating the cellulose nanocrystals from the second stream; and
recovering substantially all of the unreacted sulfuric acid in the second stream, wherein said recovering comprises:
introducing a second water-insoluble solvent to the second stream,
separating a third stream comprising substantially all of the unreacted sulfuric acid and the second water-insoluble solvent from a fourth stream comprising water, and
separating substantially all of the unreacted sulfuric acid from the second water-insoluble solvent.
18. The method of claim 17 , wherein the second water-insoluble solvent is the same as the first water-insoluble solvent.
19. The method of claim 17 , wherein the fourth stream further comprises polysaccharides.
20. The method of claim 17 , further comprising recovering substantially all of the unreacted sulfuric acid in the first stream.
21. The method of claim 20 , wherein recovering substantially all of the unreacted sulfuric acid in the first stream comprises introducing a second water-insoluble solvent to the first stream, separating a fifth stream comprising substantially all of the unreacted sulfuric acid and the second water-insoluble solvent from a sixth stream comprising the first water-insoluble solvent, and separating substantially all of the unreacted sulfuric acid from the second water-insoluble solvent.
22. The method of claim 21 , wherein the second water-insoluble solvent is different from the first water-insoluble solvent.
23. The method of claim 21 , wherein the second water-insoluble solvent has a lower boiling point than the first water-insoluble solvent.
24. The method of claim 17 , wherein the first stream comprises at least 80% of the unreacted sulfuric acid.
25. The method of claim 17 , wherein the second stream further comprises dissolved polysaccharides.