Methods for removing hemicellulose

Patent metadata

Field	Value
Publication number	US-2016369455-A9
Application number	US-201514645183-A
Country	US
Kind code	A9
Filing date	Mar 11, 2015
Priority date	Jun 30, 2010
Publication date	Dec 22, 2016
Grant date	—

Abstract

A method for treating a cellulosic material comprises extracting the cellulosic material with an extractant to selectively extract hemicellulose therein and separating the extracted hemicellulose to form a cellulosic product comprising less hemicellulose than the cellulose-containing material. The extractant comprises an amine oxide and a non-solvent. The cellulosic product retains the cellulosic fiber morphology.

First claim

We claim:

1 . A high purity α-cellulose grade pulp product purified by removing hemicellulose from cellulosic material using a mixture of amine oxide and water, wherein the high purity α-cellulose grade pulp product comprises less than 5% hemicellulose.

2 . The high purity α-cellulose pulp product of claim 1 , wherein the mixture further comprises dimethyl sulfoxide.

3 . The high purity α-cellulose pulp product of claim 1 , wherein the amine oxide is N-methylmorpholine-N-oxide.

4 . The high purity α-cellulose pulp product of claim 1 , wherein the purified wood pulp product maintains a cellulosic morphology.

5 . The high purity α-cellulose pulp product of claim 1 , wherein the removing comprises batch, co-current, or counter-current extraction.

6 . The high purity α-cellulose pulp product of claim 1 , wherein the removing comprises use of an agitated tank, hydrapulper, screw conveyor or screw extractor.

7 . The high purity α-cellulose pulp product of claim 1 , wherein solid and liquid phases are separated by a filter or centrifuge.

8 . A solvent system for reducing hemicellulose in a cellulosic material to form a hemicellulose reduced product, comprising 50-80 wt. % amine oxide and 20-50 wt. % water.

9 . The solvent system of claim 8 , further comprising dimethyl sulfoxide, dimethylformamide, methanol, ethanol, isopropanol, acetone, acetic acid or a mixture thereof.

10 . A solvent system for selectively reducing hemicellulose in a cellulosic material to form a hemicellulose reduced cellulosic product, comprising from 0.8 to 95 wt. % amine oxide and from 0.1 to 99.9 wt. % non-solvent.

11 . The solvent system of claim 10 , wherein the amine oxide is selected from the group consisting of oxides of trimethylamine, triethylamine, tripropylamine, monomethyldiethylamine, dimethylmonoethylamine, monomethyldipropylamine, N-dimethyl-, N-diethyl- or N-dipropylcyclohexylamine, N-dimethylmethylcyclohexylamine, pyridine, and pyridine N-oxide.

12 . The solvent system of claim 10 , wherein the amine oxide is a cyclic mono (N-methylamine-N-oxide) compound.

13 . The solvent system of claim 10 , wherein the amine oxide is R 1 R 2 R 3 N—O, wherein R 1 , R 2 and R 3 are alkyl chains with a chain length from 1 to 12.

14 . The solvent system of claim 10 , wherein the non-solvent is selected from the group consisting of water, alcohols, n-butanol, tert-butanol, diols, polyols, amino alcohols, aromatic solvents, halogenated solvents, aliphatic solvents, ethers, ketones esters, amides, and mixtures thereof.

15 . The solvent system of claim 10 , wherein the non-solvent is acetonitrile.

16 . The solvent system of claim 10 , wherein the non-solvent is dimethyl sulfoxide.

17 . The solvent system of claim 10 , wherein the non-solvent comprises water and an organic non-solvent.

18 . The solvent system of claim 17 , wherein the solvent system comprises from 0.01 to 12.5 wt. % water, from 50 to 98 wt. % organic non-solvent, and from 0.8 to 40 wt. % amine oxide.

19 . The solvent system of claim 10 , wherein the solvent system comprises from 0.1 to 10 wt. % amine oxide and from 90 to 99.9 wt. % non-solvent.

20 . The solvent system of claim 10 , wherein the solvent system comprises a first non-solvent and a second non-solvent, and further wherein the second non-solvent decreases the viscosity of the solvent system.

Assignees

• Celanese Int Corp

Inventors

• Li Rongfu
• Mehta Jay
• Tu Xiaoyan
• Bansal Prabuddha
• Combs Michael
• Fallon Denis
• Kizer Lawton E

Classifications

• D21H17/09 Primary

  Sulfur-containing compounds · CPC title

• D21H17/07

  Nitrogen-containing compounds · CPC title

• G01N15/1433 Primary

  using image recognition · CPC title