Nanocellulose production using lignosulfonic acid

Patent metadata

Field	Value
Publication number	US-2016237173-A1
Application number	US-201615137064-A
Country	US
Kind code	A1
Filing date	Apr 25, 2016
Priority date	Nov 30, 2012
Publication date	Aug 18, 2016
Grant date	—

Abstract

Processes disclosed are capable of converting biomass into high-crystallinity nanocellulose with low mechanical energy input. In some variations, the process includes fractionating biomass with lignosulfonic acids, to generate cellulose-rich solids; and mechanically treating the cellulose-rich solids to form nanofibrils and/or nanocrystals. The strong lignosulfonic acids created during delignification give a pH less than 1 and hydrolyze preferentially the amorphous regions of cellulose. The total mechanical energy may be less than 500 kilowatt-hours per ton. The crystallinity of the nanocellulose material may be 80% or higher, translating into good reinforcing properties for composites. The nanocellulose material may include nanofibrillated cellulose, nanocrystalline cellulose, or both. In some embodiments, the nanocellulose material is hydrophobic via deposition of lignin onto the cellulose surface. Optionally, sugars derived from amorphous cellulose and hemicellulose may be separately fermented to co-products.

First claim

What is claimed is:

1 . A process for producing a nanocellulose material, said process comprising:
(a) providing a lignocellulosic biomass feedstock; (b) fractionating said feedstock in the presence of lignosulfonic acids or a derivative thereof, to generate cellulose-rich solids and a liquid containing hemicellulose and lignin; (c) mechanically treating said cellulose-rich solids to form cellulose fibrils and/or cellulose crystals, thereby generating a nanocellulose material having a crystallinity of at least 60%; and (d) recovering said nanocellulose material.

2 . The process of claim 1 , wherein step (b) is conducted in the presence of a compound selected from the group consisting of sulfur dioxide, sulfurous acid, sulfite ions, sulfite salts, and combinations thereof.

3 . The process of claim 1 , wherein step (b) is conducted in the presence of a solvent for lignin, water, or both of these.

4 . The process of claim 1 , wherein during step (c), said cellulose-rich solids are treated with a total mechanical energy of less than 1000 kilowatt-hours per ton of said cellulose-rich solids.

5 . The process of claim 4 , wherein said total mechanical energy is less than 500 kilowatt-hours per ton of said cellulose-rich solids.

6 . The process of claim 1 , wherein step (c) further comprises treatment of said cellulose-rich solids with one or more acids.

7 . The process of claim 6 , wherein said one or more acids are selected from the group consisting of sulfur dioxide, sulfurous acid, lignosulfonic acid, acetic acid, formic acid, and combinations thereof.

8 . The process of claim 1 , said process further comprising bleaching said cellulose-rich solids prior to step (c) and/or as part of step (c).

9 . The process of claim 1 , said process further comprising bleaching said nanocellulose material during step (c) and/or following step (c).

10 . The process of claim 1 , wherein said crystallinity of said nanocellulose material is at least 70%.

11 . The process of claim 10 , wherein said crystallinity of said nanocellulose material is at least 80%.

12 . The process of claim 11 , wherein said crystallinity of said nanocellulose material is at least 85%.

13 . The process of claim 1 , wherein said nanocellulose material comprises nanofibrillated cellulose.

14 . The process of claim 1 , wherein said nanocellulose material comprises nanocrystalline cellulose.

15 . The process of claim 1 , wherein said nanocellulose material comprises nanofibrillated cellulose and nanocrystalline cellulose.

16 . The process of claim 1 , wherein said nanocellulose material is at least partially hydrophobic via deposition of at least some of said lignin onto a surface of said cellulose-rich solids during step (b).

17 . The process of claim 1 , wherein said nanocellulose material is at least partially hydrophobic via deposition of at least some of said lignin onto a surface of said nanocellulose material during step (c) or step (d).

18 . The process of claim 1 , said process further comprising chemically converting said nanocellulose material to one or more nanocellulose derivatives.

19 . The process of claim 18 , wherein said nanocellulose derivatives are selected from the group consisting of nanocellulose esters, nanocellulose ethers, nanocellulose ether esters, alkylated nanocellulose compounds, cross-linked nanocellulose compounds, acid-functionalized nanocellulose compounds, base-functionalized nanocellulose compounds, and combinations thereof.

20 . The process of claim 1 , said process further comprising recovering hemicellulosic sugars derived from said hemicellulose; fermenting said hemicellulosic sugars to produce a monomer or precursor thereof; polymerizing said monomer to produce a polymer; and combining said polymer and said nanocellulose material to form a polymer-nanocellulose composite.

Assignees

• Api Ip Holdings Llc

Inventors

• Nelson Kimberly
• Retsina Theodora
• Pylkkanen Vesa
• O'Connor Ryan

Classifications

• C08L1/02

  Cellulose; Modified cellulose · CPC title

• C07G1/00

  Low-molecular-weight derivatives of lignin (high-molecular-weight derivatives of lignin {C08H6/00}) · CPC title

• D21H11/18

  Highly hydrated, swollen or fibrillatable fibres · CPC title

• D21C9/007

  by mechanical or physical means · CPC title

• D21C5/005

  Treatment of cellulose-containing material with microorganisms or enzymes · CPC title