METHOD OF PREPARING CARBOXYMETHYL CELLULOSE Russian patent published in 2001 - IPC

FIELD: preparation of high-molecular compounds, particularly, ethers of carboxymethyl cellulose used as semifinished product for preparing purified salts of carboxymethyl cellulose as thickeners, emulsifiers, stabilizers of aqueous solutions, suspensions and emulsions. SUBSTANCE: in order to carry method into effect Na- carboxymethyl cellulose is successively converted into acid with aqueous solution of orthophosphoric acid having concentration of at least 10% and not higher than 20% for 15-30 min. Treatment with cross- linking aldehyde is combined with first washing operation and carried out for 15-30 min. Aldehyde is a aqueous solution containing 1.5-20 wt.pts of aldehyde per 100 wt.pts of sodium salt of carboxymethyl cellulose. Invention makes it possible to cut down total duration of process and individual stages, thereof, retain degree of polymerization of carboxy methyl cellulose, increase yield, reduce consumption of cross-linking agent, lower ecological hazard due to absence of organic solvents. EFFECT: more efficient preparation method. 1 tbl