New technology for clean production of chitosan and carboxymethyl chitosan by using crustacean shell raw materials

Abstract

The invention relates to a new technology for clean production of chitosan and carboxymethyl chitosan by using crustacean shell raw materials. The method comprises the following steps: crushing shrimp shells, crab shells and other crustacean shell raw materials, directly reacting in an alcohol, alkali and water mixed system without calcium or protein removal, washing, and filtering to obtain calcium carbonate-containing crude chitosan for direct use; or directly adding chloroacetic acid, carrying out a chitosan carboxymethylation one-pot boiling reaction, washing a solid obtained after the reaction, filtering, drying to obtain a crude carboxymethyl chitosan and calcium carbonate mixture for direct use, or adding water to dissolve the mixture to obtain separated calcium carbonate which can be used a filler and a solution which can be used as a product directly or after concentration drying, and carrying out alcohol precipitation to obtain pure carboxymethyl chitosan. The above crude or pure product can be widely used in the fields of papermaking, binders, coatings and sustained and controlled release fertilizers. A washed filtrate contains amino acids and small peptides, and can be used as an animal amino acid fertilizer raw material or plant amino acid fertilizer or microbial nitrogen source nutriment after solvent concentration recovery.

Description

technical field [0001] The patent of the invention relates to a new process for clean production of chitosan and carboxymethyl chitosan from crustacean raw materials, which belongs to the technical field of biomass utilization and natural product modification. Background technique [0002] Chitin is the second largest renewable resource after cellulose on the earth. It is widely found in the cell walls of arthropods, molluscs, annelids, protozoa, fungi and algae, among which crustaceans such as shrimp and crab The carapace of human beings is rich in 15%-35% chitin, and the biosynthesis of chitin is about 100 billion tons per year. The basic unit of chitin is acetylglucosamine, which is a polymer composed of 1000-3000 acetylglucosamine residues linked by β-(1→4)-glycosidic bonds. Chitosan (chitosan) is the product of N-deacetylation of chitin, and is the only nitrogen-containing basic polysaccharide that exists in large quantities in nature. Due to the existence of intramol...

AI Technical Summary

Problems solved by technology

[0005] 1) The cost of extracting chitin as a raw material is high. Shrimp shells and crab shells are decalcified with dilute acid and deproteinized by 5% to 8% lye for a long time. Pollution

[0006] 2) The acid treatment process easily leads to the degradation of chitin, wasting precious biological calcium resources

And when preparing carboxymethyl chitosan, low-temperature alkalization is required, which not only complicates the process, but also consumes a lot of alkali, energy and waste water.

[0008] 4) The existing production process of chitin and its derivatives fails to realize the full-price utilization of crustacean resources such as shrimp and crab shells, resulting in waste of biological calcium and protein resources and serious environmental pollution, resulting in high production costs and expensive products. Restricts the development of abundant crustacean resources

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