Process for preparing ultrahigh molecular weight and low viscosity esterified cellulose ether

摘要

There is provided a modified process for preparing an esterified cellulose ether comprising the steps of i) preparing a reaction mixture comprising a cellulose ether, an aliphatic monocarboxylic anhydride, a dicarboxylic anhydride, and a reaction diluent, and mixing the components of the reaction mixture Heating the reaction mixture to a temperature of from 60 캜 to 110 캜 to effect an esterification reaction, and ii) before the esterification reaction is completed, adding an additional amount of the reaction diluent continuously or in succession To the reaction mixture at a temperature higher than the reaction temperature of the reaction mixture, and further conducting the esterification reaction.