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

A carboxymethyl chitosan and crustacean technology, which is applied in the field of biomass utilization and natural product modification, can solve the problems of high acid-base and energy consumption, waste of biological calcium resources, and high cost of chitin extraction, and achieves improved conversion. rate, enhance nucleophilic ability, overcome the effect of "shielding" effect

Active Publication Date: 2015-07-22
XIAMEN UNIV +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] Add solid sodium hydroxide to the isopropanol-water mixing system, stir at 60°C for a period of time to form a paste liquid, then weigh the shrimp shell powder and add them to the above mixture, stir for 3 hours, the chitin is fully deacetylated, and the solid Add water and wash to obtain chitosan and calcium carbonate mixture, then dissolve chitosan and calcium carbonate with hydrochloric acid, reverse precipitate chitosan with ethanol, wash repeatedly with 70% alcohol aqueous solution to remove calcium chloride to obtain pure chitosan. The degree of deacetylation was determined by acid-base titration. See Table 2, Table 3, and Table 4 for relevant experimental results under different m (shrimp shell powder): m (sodium hydroxide), water content, and temperature.

[0040] The effect of the amount of epidihydric sodium hydroxide on the degree of deacetylation of chitin

[0041]

[0042] Table 3 The effect of water content on the degree of deacetylation of chitin

[...

Embodiment 2

[0048] Add 15g of sodium hydroxide solid to 100ml of isopropanol-water mixed system containing 10% water, stir at 60°C for a period of time to form a paste liquid, then weigh 45g of decalcified shrimp shell powder and add to the above mixture, 60 Under electric stirring at ℃ for 3h, chitin is fully deacetylated. Chloroacetic acid was added in 3 to 7 times respectively, and chitosan was carboxymethylated for 3 hours. The solid obtained by filtration and separation was washed with 70% ethanol solution to obtain a mixture of carboxymethyl chitosan and calcium carbonate. The mixture was dissolved in water, and the supernatant obtained by centrifugation was added with 5 times the volume of ethanol to precipitate, and then the precipitate was washed with 80% ethanol three times, dried to obtain pure carboxymethyl chitosan, and the carboxylation degree of the product was determined by potentiometric titration. different m (虾壳粉) :m (-氯乙酸) 1. See Table 5 and Table 6 for the relevant...

Embodiment 3

[0054] Add 30g of sodium hydroxide solid to the 100ml ethanol-water mixed system containing 10% water and stir evenly, then weigh 45g of decalcified shrimp shell powder and add it to the above mixture, stir and reflux at 80°C for 3 hours to fully deacetylate chitin . Then add monochloroacetic acid in 3 to 7 times, and carboxymethylate chitosan for 3 hours. The product was washed with an aqueous alcohol solution and dried to obtain 28 g of the mixture. Water was added to dissolve and precipitate 21 g of calcium carbonate, and the solution was reverse-precipitated with ethanol to obtain 6.8 g of carboxymethyl chitosan. The deacetylation degree of carboxymethyl chitosan product is 0.72, and the carboxylation degree is 0.69.

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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...

Claims

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Application Information

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IPC IPC(8): C08B37/08
Inventor 洪燕平尹应武王光琴洪专
Owner XIAMEN UNIV
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