A modified process for producing an esterified cellulose ether is provided which comprises the stages of i) preparing a reaction mixture comprising a cellulose ether an aliphatic monocarboxylic acid anhydride a dicarboxylic acid anhydride and a reaction diluent and heating the reaction mixture to a temperature of from 60°C to 110 °C prior to during or after mixing the components of the reaction mixture to conduct an esterification reaction and ii) before the esterification reaction is completed adding an additional amount of reaction diluent continuously or in one or more portions to the reaction mixture and allowing the esterification reaction to further proceed.
