METHOD FOR PRODUCING LOW-MOLECULAR CHITOSAN AND CHITOSAN OLIGOMERS Russian patent published in 2017 - IPC C08B37/08 C12P19/04 B01D9/02 

FIELD: chemistry.

SUBSTANCE: method for producing low-molecular chitosan and chitosan oligomers by a chemical depolymerization method, including hydrolysis of chitosan in the presence of an acid, followed by filtration, fractionation, purification and drying of products, characterized in the fact that hydrolysis of chitosan is carried out with 2.5-12.5% dilute nitric acid at a temperature of 70°C, followed by separation of the hydrolyzate into two fractions - a precipitate of low-molecular chitosan and a mother liquor, then chitosan oligomers are precipitated from the mother liquor during addition of isopropyl alcohol and cooling. Then, both products are washed with isopropyl alcohol and air-dried, finally, the products of chitosan depolymerization are redissolved in water and dried lyophilically.

EFFECT: method is proposed for producing a product of a narrow fractional composition which is highly soluble in water.

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