New method for preparing water-soluble carboxymethyl chitosan from chitin

Abstract

The invention relates to a new method for improving a production process of water-soluble carboxymethyl chitosan by taking chitin as a raw material and sodium chloroacetate as a reactant. The method is characterized by taking chitin powder instead of chitosan powder as the raw material and adopting sodium chloroacetate for replacing high-irritation and corrosion chloroacetic acid used in conventional production for reaction, wherein the ethanol solution in certain concentration is used as the reaction solvent. The prepared carboxymethyl chitosan is capable of dissolving within the pH scope from 6.0 to 8.0, the degree of substitution is more than 80%, the degree of deacetylation is more than 70% and the purity is more than or equal to 85%. The chitosan derivative has excellent bacteria resistance, bacteriostasis, and moisture absorption and moisture retention performance and can be further purified for wide application to the fields of medicines, food or cosmetics. See abstract figuresfor the details of a schematic diagram for the process of preparing water-soluble carboxymethyl chitosan from chitin.

Description

technical field

[0001] The invention relates to the field of fine chemical industry, belongs to marine chemical engineering technology, is a new N, O-substituted carboxymethyl chitosan preparation technology, and is a water-soluble carboxymethyl chitosan prepared from chitin new method. Water-soluble N, O-substituted carboxymethyl chitosan is obtained by reacting chitin powder and sodium chloroacetate in ethanol solution. Compared with the prior art, with the preparation method of the present invention, the raw material utilization rate is high, the working environment is significantly improved, the product purity is high, and the yield is high. This type of chitosan derivative C 6 Bit - 0H and C 2 The degree of substitution on -NH2 is as high as 80-110%. It has good water solubility, good antibacterial and antibacterial properties, and moisture absorption and moisturizing properties. Further purification can be widely used in the fields of medicine, food or cosmetics. Bac...

Examples

Embodiment 1

[0021] Add 20g of chitin powder to a beaker equipped with an electric stirrer, prepare 200g of 45% NaOH solution, pour it into the chitin powder, stir for 1.5h to alkalize, separate solid and liquid, add 120ml of 95% ethanol, and stir evenly Add 40g of sodium chloroacetate, react at 60°C for 3.0 hours, separate the solid and liquid after the reaction, adjust the pH to neutral with dilute acid, wash twice with 200ml of 75% ethanol solution, dehydrate once with 100ml of 95% ethanol , vacuum-dried to obtain the product, according to the method in "YY0953-2015 Medical Carboxymethyl Chitosan", the pH was 7.0, the degree of substitution was 96.1%, the degree of deacetylation was 81.7%, and the purity was 86.3%.

Embodiment 2

[0023] Add 20g of chitin powder to a beaker equipped with an electric stirrer, prepare 200g of 45% NaOH solution, pour it into the chitin powder, stir for 1.5h for alkalization, separate solid and liquid, add 150ml of 95% ethanol, and stir well Then add 50g of sodium chloroacetate, react at 65°C for 3.5 hours, separate the solid and liquid after the reaction, adjust the pH to neutral with dilute acid, wash twice with 200ml of 75% ethanol solution, and dehydrate with 100ml of 95% ethanol Once, the product was vacuum-dried to obtain a pH of 7.2 according to the method in "YY0953-2015 Medical Carboxymethyl Chitosan", the degree of substitution was 92.3%, the degree of deacetylation was 78.9%, and the purity was 90.8%.

Embodiment 3

[0025] Weigh 10kg of chitin raw material and put it into a stirring tank, prepare 100kg of NaOH solution with 45% concentration, stir and alkalize at room temperature for 2 hours, separate solid and liquid, add 60kg of 95% concentration ethanol solution, and then add 20kg of sodium chloroacetate to In the system, the reaction was carried out at 60°C for 5.0 hours. After the reaction, the crude product was dissolved in purified water, filtered through a 3 μm precision filter, precipitated with 95% ethanol solution, separated from solid and liquid, adjusted to neutral with dilute acid, and washed twice with 75% ethanol solution. % concentration ethanol was dehydrated once, vacuum-dried, pulverized and passed through an 80-mesh sieve to obtain the product. After testing, the pH of the product is 7.3, the degree of substitution is 111.2%, the degree of deacetylation is 87.9%, and the purity is 94.7%.

technical field

[0001] The invention relates to the field of fine chemical industry, belongs to marine chemical engineering technology, is a new N, O-substituted carboxymethyl chitosan preparation technology, and is a water-soluble carboxymethyl chitosan prepared from chitin new method. Water-soluble N, O-substituted carboxymethyl chitosan is obtained by reacting chitin powder and sodium chloroacetate in ethanol solution. Compared with the prior art, with the preparation method of the present invention, the raw material utilization rate is high, the working environment is significantly improved, the product purity is high, and the yield is high. This type of chitosan derivative C 6 Bit - 0H and C 2 The degree of substitution on -NH2 is as high as 80-110%. It has good water solubility, good antibacterial and antibacterial properties, and moisture absorption and moisturizing properties. Further purification can be widely used in the fields of medicine, food or cosmetics. Bac...

Examples

Embodiment 1

[0021] Add 20g of chitin powder to a beaker equipped with an electric stirrer, prepare 200g of 45% NaOH solution, pour it into the chitin powder, stir for 1.5h to alkalize, separate solid and liquid, add 120ml of 95% ethanol, and stir evenly Add 40g of sodium chloroacetate, react at 60°C for 3.0 hours, separate the solid and liquid after the reaction, adjust the pH to neutral with dilute acid, wash twice with 200ml of 75% ethanol solution, dehydrate once with 100ml of 95% ethanol , vacuum-dried to obtain the product, according to the method in "YY0953-2015 Medical Carboxymethyl Chitosan", the pH was 7.0, the degree of substitution was 96.1%, the degree of deacetylation was 81.7%, and the purity was 86.3%.

Embodiment 2

[0023] Add 20g of chitin powder to a beaker equipped with an electric stirrer, prepare 200g of 45% NaOH solution, pour it into the chitin powder, stir for 1.5h for alkalization, separate solid and liquid, add 150ml of 95% ethanol, and stir well Then add 50g of sodium chloroacetate, react at 65°C for 3.5 hours, separate the solid and liquid after the reaction, adjust the pH to neutral with dilute acid, wash twice with 200ml of 75% ethanol solution, and dehydrate with 100ml of 95% ethanol Once, the product was vacuum-dried to obtain a pH of 7.2 according to the method in "YY0953-2015 Medical Carboxymethyl Chitosan", the degree of substitution was 92.3%, the degree of deacetylation was 78.9%, and the purity was 90.8%.

Embodiment 3

[0025] Weigh 10kg of chitin raw material and put it into a stirring tank, prepare 100kg of NaOH solution with 45% concentration, stir and alkalize at room temperature for 2 hours, separate solid and liquid, add 60kg of 95% concentration ethanol solution, and then add 20kg of sodium chloroacetate to In the system, the reaction was carried out at 60°C for 5.0 hours. After the reaction, the crude product was dissolved in purified water, filtered through a 3 μm precision filter, precipitated with 95% ethanol solution, separated from solid and liquid, adjusted to neutral with dilute acid, and washed twice with 75% ethanol solution. % concentration ethanol was dehydrated once, vacuum-dried, pulverized and passed through an 80-mesh sieve to obtain the product. After testing, the pH of the product is 7.3, the degree of substitution is 111.2%, the degree of deacetylation is 87.9%, and the purity is 94.7%.

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