Chitosan preparation method

Abstract

The invention relates to a chitosan preparation method, which is characterized in that the method comprises the following steps: 1) gas explosion swelling: loading chitin raw materials into a gas explosion swelling tank, injecting a gas explosion swelling medium which adopts one kind of materials of water vapor, water, ammonia water and ethanol, instantaneously releasing pressure in the gas explosion swelling tank, and spraying the chitin raw materials into a normal pressure container to obtain fine chitin materials; 2) hydrolysis; 3) filtration; 4) soaking and water washing; 5) filtration; and 6) drying. Compared with the prior art, the invention has the characteristics that the chitin pretreated by a gas explosion swelling method is adopted as raw materials, the raw materials have high chemical activity, and low reaction temperature and short reaction time can be adopted in the hydrolysis process, so the generation of the secondary reaction is inhabited, and the decomposition of the chitosan is avoided. Thereby, the invention has the following advantages: 1) the consumption of alkali and energy sources is little;2) the reaction time is short; 3) the yield is high; 4) the production cost is low; 5) the pollutant discharge is little; and 6) the product quality is stable.

Description

technical field [0001] The invention relates to a method for preparing chitosan, in particular to a method for preparing chitosan using chitin treated by an air explosion expansion method as a raw material. Background technique [0002] Chitosan, English name chitosan, alias soluble chitin, chitosan, chitosan. Chemical structural formula: B-(1→4)-2-deoxy-D-glucan, molecular formula: (C 6 h 11 0 4 N) n . Chitosan is the product of deacetylation of chitin, insoluble in water but soluble in dilute acid. Its chemical structure is a high-molecular alkaline polysaccharide polymer with cations, and has unique physical and chemical properties and biological activation functions. It is a natural cationic polysaccharide obtained by deacetylation of chitin. It has degradability, good film-forming property, good biocompatibility and certain excellent properties such as antibacterial and antitumor. It is widely used in medicine, Food, chemical, environmental protection and other i...

AI Technical Summary

Problems solved by technology

Because chitin extracted from shrimp and crab shells has a dense crystal structure, it is usually pretreated by pulverization. Such a pretreatment method is difficult to change its dense crystal structure, and it is also difficult to make it chemically modified. Therefore, hydrolysis The reaction has to adopt higher concentration of alkali, higher reaction temperature and longer reaction time, resulting in the following disadvantages: 1) the consumption of alkali and energy is large; 2) the reaction time is long; 3) the yield is low; 4 ) high production cost; 5) serious pollutant discharge; 6) unstable product quality;