Processing

Please wait...

Settings

Settings

Goto Application

1. AU2017210775 - Production of crystalline cellulose

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]
THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:
1.           A method of producing microcrystalline cellulose (MCC) from a cellulosic material, comprising the steps of:
(a) reacting the cellulosic material in an aqueous slurry comprising a transition metal catalyst and a hypohalite solution having an initial pH greater than about 6.0 and a final pH less than about 9.0; and
(b) recovering a microcrystalline cellulose fraction.
2.           The method of claim 1, wherein the hypohalite comprises hypochlorite, hypoiodite, or hypobromite.
3.           The method of claim 1 or 2, wherein the initial pH of the slurry is between about 9.0 to about 12.0.
4.           The method of claim 1, 2 or 3, wherein the final pH of the slurry is below about 8.0.
5.           The method of claim 4, wherein the final pH of the slurry is below about 7.0.
6.           The method of any one of claims 1-5, wherein the slurry has an initial oxidation reduction potential (ORP) of greater than about 500 mV.
7.           The method of claim 6, wherein the slurry has a final ORP of less than about 0.0 mV.
8.           The method of any one of claims 1-7, wherein the slurry further comprises a buffer.
9.           The method of claim 8, wherein the buffer comprises a phosphate and a polyvalent organic acid.
10.         The method of any one of claims 1-9, wherein the ratio of hypohalite to cellulosic material in the slurry is between about 1 mol/kg to about 10 mol/kg (dry weight basis).
11. The method of any one of claims 1-10, wherein the slurry is heated to between about 500 C and about 85° C.
12. The method of any one of claims 1-11, wherein reaction of step (a) is allowed to proceed until a significant drop of oxidation-reduction potential is observed, the resulting microcrystalline cellulose is collected and washed in an alkaline solution, and step (a) is repeated to produce cellulose nanocrystals (CNCs).
13. The method of claim 12, wherein the alkaline solution comprises a solution of NaOH having a pH of about 12.0.
14. The method of claim 12, wherein the alkaline solution is heated to between about 30°C and about 90° C.
15. The method of any one of claims 1-11, wherein the reaction of step (a) is continued by adding at least one additional amount of hypohalite.
16. The method of claim 15, wherein additional hypohalite is added after the drop of oxidation-reduction potential, which addition step is repeated at least twice.
17. The method of any one of claims 1-16, wherein the total amount of hypohalite added is between about 1 mol/kg of cellulosic material to about 20 mol/kg (dry weight).