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Method for preparing carboxymethyl chitosan

A technology of carboxymethyl chitosan and carboxymethyl group is applied in the field of preparing carboxymethyl chitosan with high viscosity and high degree of substitution, which can solve the problem of molecular weight drop, unapplied carboxymethyl chitosan and low product viscosity and other problems to achieve the effect of reducing the degree of deacetylation

Active Publication Date: 2014-01-29
SHANGHAI CHUNLU BIOCHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, there are following deficiencies in the above-mentioned traditional techniques: 1. The pH range of the dissolution of carboxymethyl chitosan obtained by the traditional method is all greater than or equal to 7, and in industries such as food, medicine, cosmetics, for carboxymethyl chitosan dissolution The pH range requirements are all greater than or equal to 5, that is, it can also be dissolved in acidic solution, so the carboxymethyl chitosan produced by the traditional process cannot be applied in the above-mentioned fields at all; 2. The high reaction temperature of the traditional process causes chain scission, Lead to a sharp drop in molecular weight and low product viscosity

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The concrete processing steps of preparing carboxymethyl chitosan in the present embodiment are as follows:

[0025] (1) Deacetylation reaction: add 40Kg of chitin to 600Kg of 50% sodium hydroxide aqueous solution, react under stirring conditions for 4h, the reaction temperature is 75°C, then stand at 10°C for 24h, and then at 75°C Stir for 2h, and finally centrifuge to obtain 150Kg chitosan sodium salt;

[0026] (2) Carboxylation reaction: under alkaline conditions, add 400Kg of absolute ethanol and 80Kg of chloroacetic acid to the 150Kg of chitosan sodium salt obtained in step (1), stir at 50°C for 24h, and obtain carboxymethyl after centrifugation Carboxymethyl chitosan sodium salt; dissolve carboxymethyl chitosan sodium salt in water, adjust the pH to neutral, then wash and precipitate with ethanol repeatedly, and obtain carboxymethyl chitosan after centrifugal drying.

[0027] The degree of deacetylation of chitosan sodium salt in step (1) of this embodiment is 0....

Embodiment 2

[0029] The concrete processing steps of preparing carboxymethyl chitosan in the present embodiment are as follows:

[0030] (1) Deacetylation reaction: add 40Kg of chitin to 500Kg of 65% sodium hydroxide aqueous solution, react under stirring conditions for 3h, the reaction temperature is 80°C, then stand at 15°C for 30h, and then at 80°C Stir for 1 hour, and finally obtain chitosan sodium salt by centrifugal dehydration;

[0031] (2) Carboxylation reaction: under alkaline conditions, add 300Kg absolute ethanol and 150Kg chloroacetic acid to the chitosan sodium salt obtained in step (1), stir at 40°C for 24h, and obtain carboxymethyl after centrifugation Chitosan sodium salt: Dissolve carboxymethyl chitosan sodium salt in water, adjust the pH to neutral, then repeatedly wash and precipitate with ethanol, and obtain carboxymethyl chitosan after centrifugal drying.

[0032] The degree of deacetylation of chitosan sodium salt in step (1) of this embodiment is 0.65; the degree of...

Embodiment 3

[0034] The concrete processing steps of preparing carboxymethyl chitosan in the present embodiment are as follows:

[0035] (1) Deacetylation reaction: add 40Kg of chitin to 600Kg of 40% sodium hydroxide aqueous solution, react under stirring conditions for 6h, the reaction temperature is 50°C, then stand at 0°C for 20h, and then at 50°C Stir for 4h, and finally obtain chitosan sodium salt by centrifugal dehydration;

[0036] (2) Carboxylation reaction: under alkaline conditions, add 500Kg absolute ethanol and 100Kg chloroacetic acid to the chitosan sodium salt obtained in step (1), stir at 70°C for 20h, and obtain carboxymethyl after centrifugation Chitosan sodium salt: Dissolve carboxymethyl chitosan sodium salt in water, adjust the pH to neutral, then repeatedly wash and precipitate with ethanol, centrifuge and dry to obtain the finished carboxymethyl chitosan.

[0037] The degree of deacetylation of chitosan sodium salt in step (1) of this embodiment is 0.5; The carboxyme...

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Abstract

The invention discloses a method for preparing carboxymethyl chitosan. The method comprises the following steps of by using chitin as a material, alkalifying the chitin, carrying out deacetylation reaction by using a cooling-heating alternative method to produce chitosan sodium salt; and then, carrying out carboxylation under an alkaline condition to obtain a carboxymethyl chitosan product. The method disclosed by the invention is simple in process and easy to control, so that a chain scission phenomenon appearing due to long-term high temperature reaction during deacetylation reaction of a chitosan molecular chain is avoided, thereby obtaining carboxymethyl chitosan which is high in viscosity, high in degree of substitution and better in water solubility; moreover, the method is suitable for large-scale industrial production.

Description

technical field [0001] The invention relates to a method for preparing carboxymethyl chitosan, in particular to a method for preparing carboxymethyl chitosan with high viscosity and high degree of substitution. Background technique [0002] Chitin is a non-toxic and tasteless white or off-white translucent solid, which is difficult to dissolve in water, dilute acid, dilute alkali and general organic solvents, but chitin is treated with concentrated alkali to remove more than 55% of its N-acetyl group It becomes soluble chitin, that is, chitosan. The chemical name of chitosan is β-(1,4)-2-amino-2-deoxy-β-D-glucose. Carboxymethyl chitosan is a water-soluble chitosan derivative obtained by modifying chitosan. It has antibacterial properties and is an amphoteric polyelectrolyte. It has many applications in cosmetics, fresh-keeping, and medicine. . [0003] There are many methods for producing carboxymethyl chitosan in the prior art, for example, patent CN1431229A discloses a p...

Claims

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Application Information

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IPC IPC(8): C08B37/08
Inventor 徐宇帆
Owner SHANGHAI CHUNLU BIOCHEM CO LTD
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