CONTINUOUS ADDITION PROCESS FOR PREPARING HYDROXYALKYLALKYLCELLULOSE ETHERS

摘要

Higher reaction efficiencies are seen in cellulose etherification reactions when the reagents are continuously added to alkali cellulose at elevated temperatures. In particular, mixed hydroxyalkylcellulose ethers made from a C3 or higher alkylene oxide and an etherifying agent other than an alkyle oxide are prepared at elevated temperatures with higher reaction efficiencies using this process. In an especially preferred embodiment, hydroxypropylmethylcellulose is prepared by continuously adding propylene oxide to heated cellulose containing a small amount of caustic, adding more caustic and then continuously adding chloromethane at elevated temperatures.