METHOD OF DISSOLVING CELLULOSE Russian patent published in 1998 - IPC

FIELD: chemical industry. SUBSTANCE: present invention describes methods of dissolving cellulose in N-oxides of pyridine derivatives to obtain solutions suitable for making molding products [e.g. fibers or films], cellulose being regenerated from solution by precipitation into aqueous or aqueous organic bath. Cellulose is dissolved in 4-alkoxypyridine-N-oxide of general formula: wherein R is CH₃ or C₂H₅. Depending on the desired concentration and viscosity of cellulose solution and also on stability of solution and permissible destruction of cellulose during dissolution process, prior to or after dissolution, 4-alkoxypyridine- N- oxide is mixed with protolytic and/or aprotic liquids at not greater than 1:1 ratio. Dissolution of cellulose is carried out at 40-125 C. Dissolution time varies from 20 min to 1 h. Cellulose is first ground to increase surface contact with solvent and to make dissolution more effective. Clear homogeneous cellulose solutions which can be kept for several days are formed, and viscosity of solution varies insignificantly. After multiple use of solvent, pyridine compound waste is subjected to chemical or biochemical purification. Mixtures intended for dissolution purposes can be both separated and reused after regeneration of cellulose from solution. EFFECT: more efficient dissolution method. 3 cl, 3 tbl