Method for preparing cellulose ether having low degree of polymerization and cellulose ether prepared thereby

摘要

Provided is a method for preparing a cellulose ether having a low degree of polymerization and undergoing less yellowing and a cellulose ether prepared thereby. Specifically, provided is a method for preparing a cellulose ether having a low degree of polymerization, the method including a step of bringing pulp and an alkali metal hydroxide solution into contact with each other or mixing them to obtain a corresponding alkali cellulose, a first depolymerization step of reacting the alkali cellulose with oxygen to adjust a viscosity reduction percentage of the alkali cellulose to from 10 to 95%, a step of reacting the depolymerized alkali cellulose with an etherifying agent, a step of washing and drying the reaction product to obtain a cellulose ether, and a second depolymerization step of bringing the cellulose ether into contact with hydrochloric acid to adjust a viscosity reduction percentage of the cellulose ether from 40 to 99.9%.

主权项

1. A method for preparing a cellulose ether having a low degree of polymerization, the method comprising:
a step of bringing pulp and an alkali metal hydroxide solution into contact with each other or mixing them to obtain a corresponding alkali cellulose, a first depolymerization step of reacting the alkali cellulose with oxygen to adjust a viscosity reduction percentage of the alkali cellulose to from 10 to 95% to obtain a depolymerized alkali cellulose, a step of reacting the depolymerized alkali cellulose with an etherifying agent to obtain a reaction product, a step of washing and drying the reaction product to obtain a cellulose ether of which an aqueous 2% by weight solution has a viscosity of from 30 to 10000 mPa·s, and a second depolymerization step of bringing the cellulose ether into contact with hydrochloric acid to adjust a viscosity reduction percentage of the cellulose ether to from 40 to 99.9%.