METHOD OF PREPARING CHITIN AND METHOD OF PREPARING CHITOSAN Russian patent published in 1999 - IPC

FIELD: chemical industry. SUBSTANCE: described is method of preparing chitin which comprises cultivating synanethropic flies on solid organic waste, e.g. pigs' manure, flies and/or forms of stage-by-stage development thereof are used as chitin-containing stock from which chitin-containing fraction is isolated, the latter is treated with 1.5-5.0 % solution of strong inorganic acid for 1.5-2 hours under stirring, at 18-30 C and solid to liquid phase ratio of 1:(3-4) by weight. Solid phase is washed with water and said phase is then treated with 2.0-5.0% alkali solution for 1.5-3.0 hours at solid to liquid phase ratio of 1:(3-5) by weight under stirring at 90-1000, and contact of reaction mixture with air is avoided. Precipitate is thereafter washed successively with ethyl alcohol and chloroform and dried at 18-30 C. Also described is method of preparing chitosan. EFFECT: wider range of accessible stock and cheaper preparation of chitin and chitosan, and combined flowsheet for processing waste and preparation of chemical product. 14 cl, 4 ex, 1 dwg