Method for producing depolymerized cellulose ether

Patent metadata

Field	Value
Publication number	US-12018098-B2
Application number	US-202117505920-A
Country	US
Kind code	B2
Filing date	Oct 20, 2021
Priority date	Oct 22, 2020
Publication date	Jun 25, 2024
Grant date	Jun 25, 2024

Abstract

There is provided a method for producing a depolymerized cellulose ether, the method suppressing the formation of coarse aggregates during the contact with an acid aqueous solution in a depolymerization reaction, and reducing the amounts of aggregates and black contaminants, while suppressing yellowness. More specifically, there is provided a method for producing a depolymerized cellulose ether, the method including a depolymerization step of depolymerizing a cellulose ether by bring the cellulose ether of 45 to 95° C. into contact with an acid aqueous solution of 55 to 98° C. to obtain a depolymerized cellulose ether.

First claim

The invention claimed is:

1. A method for producing a depolymerized cellulose ether, the method comprising a step of depolymerizing a cellulose ether by bringing the cellulose ether of 45 to 95° C. into contact with a hydrogen chloride aqueous solution having a temperature of 55 to 98° C. and a concentration of more than 0% by mass and not more than 35% by mass to obtain a depolymerized cellulose ether, wherein the hydrogen chloride aqueous solution is added to the cellulose ether.

2. The method for producing a depolymerized cellulose ether according to claim 1 , wherein the temperature of the cellulose ether to be brought into contact with the hydrogen chloride aqueous solution and the temperature of the hydrogen chloride aqueous solution are both in the range of 65 to 85° C.

3. The method for producing a depolymerized cellulose ether according to claim 1 , wherein a content of water in a depolymerization reaction of the depolymerization step is 1.0 to 5.0% by mass based on the total mass of the depolymerization reaction.

4. The method for producing a depolymerized cellulose ether according to claim 3 , wherein the water in the depolymerization reaction is a total of water in the cellulose ether to be brought into contact with the hydrogen chloride aqueous solution and water in the hydrogen chloride aqueous solution.

5. The method for producing a depolymerized cellulose ether according to claim 1 , wherein the cellulose ether is selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose.

6. The method for producing a depolymerized cellulose ether according to claim 2 , wherein a content of water in a depolymerization reaction of the depolymerization step is 1.0 to 5.0% by mass based on the total mass of the depolymerization reaction.

7. The method for producing a depolymerized cellulose ether according to claim 6 , wherein the water in the depolymerization reaction is a total of water in the cellulose ether to be brought into contact with the hydrogen chloride aqueous solution and water in the hydrogen chloride aqueous solution.

8. The method for producing a depolymerized cellulose ether according to claim 6 , wherein the cellulose ether is selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose.

9. The method for producing a depolymerized cellulose ether according to claim 7 , wherein the cellulose ether is selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose.

10. The method for producing a depolymerized cellulose ether according to claim 2 , wherein the cellulose ether is selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose.

11. The method for producing a depolymerized cellulose ether according to claim 3 , wherein the cellulose ether is selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose.

12. The method for producing a depolymerized cellulose ether according to claim 4 , wherein the cellulose ether is selected from the group consisting of alkyl cellulose, hydroxyalkyl cellulose and hydroxyalkyl alkyl cellulose.

Assignees

• Shinetsu Chemical Co

Inventors

• Miki Kentaro
• Kitamura Akira
• Narita Mitsuo

Classifications

• C08B11/08 Primary

  with hydroxylated hydrocarbon radicals; Esters, ethers, or acetals thereof · CPC title

• C08B11/04

  with substituted hydrocarbon radicals · CPC title

• C08B11/20 Primary

  Post-etherification treatments of chemical or physical type, {e.g. mixed etherification in two steps}, including purification · CPC title

• C08B11/02 Primary

  Alkyl or cycloalkyl ethers · CPC title