water soluble hydroxyethylcellulose substitution low, its derivatives, preparation process and their uses

摘要

A slurry process for producing a composition comprising hydroxyethylcellulose (HEC) having hydroxyethyl groups that are uniformly distributed on the cellulose backbone wherein the water solubility is greater than 90% and the hydroxyethyl molar substitution (HEMS ) is in the range of 0.7 to 1.3, said process comprising a) mixing and reacting cellulose, water and alkali in an organic solvent for a sufficient time and sufficient temperature to form an alkali cellulose mixture, wherein the molar ratio of water relative to the anhydroglucose (AGU) is in the range of 5 to 35 and the molar ratio of alkali to AGU is greater than 1.6, B) adding a sufficient amount of oxide ethylene to produce the desired HE-MS, C) adding a sufficient amount of acid continuously to reduce the molar ratio of alkali to AGU less than 0.4 and pre ferentemente more than 0.04, while reacting the ethylene oxide with the alkali cellulose at a sufficient temperature and for sufficient time to form a HEC product soluble in water with a hydroxyethyl molar substitution in the range of 0 time 7 to 1.3 and a ratio of unsubstituted trimers (U3R) exceeding 0.21.