PRODUCTION OF ALKALI METAL SALT OF CARBOXYMETHYLCELLULOSE ETHER OF LOW DEGREE SUBSTITUTION

摘要

PURPOSE:To produce an alkali metal salt of carboxymethylcellulose ether of a low degree substitution and excellent salt water resistance, by adding an etherifying agent to a specified alkali cellulose and etherifying it. CONSTITUTION:Water-containing isopropyl alcohol is mixed with cellulose and 2.0-6.0mol, per anhydroglucose unit of the cellulose, of an alkali (e.g., NaOH), and the mixture is reacted at 10-30 deg.C for 60-120min to obtain alkali cellulose. An organic acid isopropyl ester (e.g., isopropyl formate) and isopropyl monochloroacetate are added in small portions to the alkali cellulose at 10-40 deg.C so that the amount of the alkali in the reaction system may be 0.95-1.20mol%, based on anhydroglucose unit of the cellulose. The mixture is agitated at 10-30 deg.C for 30min and is ehterified at 60-80 deg.C for 60-360min to obtain an alkali metal salt of carboxymethylcellulose ether of a low degree substitution (i.e. 0.45-0.75).