FIELD: chemical technology. SUBSTANCE: method involves the successive extraction of chitin-containing raw with nonpolar fluidized gas in ultrasonic oscillation field under pressure above atmospheric followed by pressure drop to normal value, water, ammonium hydroxide at liquid ammonium dispersion in water under conditions providing phase transfer of ammonia with water, acid, water, alkaline and water and obtaining the end product as a solid residue. Method is used for chitosan isolation from biological raw. EFFECT: increased output and purity of chitosan.
