Patent ID: 9371399
Filing Date: 2016-06-21
CPC Classification: C08B

Claim Text:
1. A method for producing cellulose ether, comprising at least the steps of: depolymerizing, in the presence of an oxygen-containing gas flow, alkali cellulose obtained by bringing a pulp into contact with an alkali solution, while calculating a consumed amount of oxygen by alkali cellulose from measured values of feeding and discharging amounts of oxygen in the oxygen-containing gas flow, to produce depolymerized alkali cellulose having a degree of polymerization controlled, wherein feeding of the oxygen-containing gas flow is stopped when the consumed amount of oxygen by the alkali cellulose reaches 0.1 to 10 normal liter per kilogram of cellulose contained by the pulp and used in production of the alkali cellulose, wherein the consumed amount of oxygen by the alkali cellulose is calculated from equation (1): wherein the units for V are normal liter/kg and V represents the consumed amount of oxygen per kilogram of cellulose in the pulp used in production of the alkali cellulose, and Dp adding an etherifying agent to the depolymerized alkali cellulose.