A method for homogeneously preparing carboxychitin with low degree of deacetylation and its application

A technology with low deacetylation degree carboxyl group and deacetylation degree, which is applied in the field of material science, can solve problems such as difficulty in ensuring product quality and uniformity of substitution degree, difficulty in controlling the reaction process, and large environmental pollution, achieving high application development value, replacing The effect of uniform degree and simple preparation process

Active Publication Date: 2017-01-25
WUHAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Usually carboxymethyl chitin is synthesized by using chloroacetic acid as an etherifying agent, using concentrated sodium hydroxide solution (45-65%) and isopropanol as a medium to react [T.K. Sini et al., Study of the influence of processing parameters on the production of carboxymethylchitin, 2005, Polymer, 46, 3128-3131; Japanese patent JP161391 / 78; Chinese invention patent CN03118437.5], the use of organic solvents in the reaction process, environmental pollution, high production costs
At the same time, because the reaction is carried out under heterogeneous conditions, the reaction temperature is high, and the reaction process is difficult to control. Chitin also has a certain degree of degradation and deacetylation (up to 50%) under concentrated alkali conditions [K. Kurita, Controlled functionalization of the polysaccharide chitin,2001, Progress in Polymer Science 26N9, 1921-1971], it is difficult to guarantee product quality and uniformity of substitution

Method used

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  • A method for homogeneously preparing carboxychitin with low degree of deacetylation and its application
  • A method for homogeneously preparing carboxychitin with low degree of deacetylation and its application
  • A method for homogeneously preparing carboxychitin with low degree of deacetylation and its application

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Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] First prepare a mixture of sodium hydroxide: urea: pure water = 6:3:91 (mass ratio), add 0.5g of chitin to 100g of the above mixture and mix well at -12~-20 o Freeze at C for 72 hours, thaw at 5-12 o C fully stirred to obtain a 0.5wt% homogeneous chitin aqueous solution. Add a mixed solution containing 7g of chloroacetic acid, 4.6g of sodium hydroxide, 1g of urea and 20mL of pure water to the homogeneous chitin aqueous solution. o C (low temperature first, then slowly increase the temperature, control the reaction solution to be a homogeneous system) and stir for 8 hours, then adjust the pH value to 6.9 with 1M hydrochloric acid, and dialyze with distilled water for 7 days to remove small molecular substances such as urea and salt in the solution , freeze-dried to obtain sponge powder carboxyl-modified chitin. Compared with the raw material chitin spectrogram, the infrared spectrogram recorded after the product was acidified with hydrochloric acid, at 1720 cm -1 A n...

Embodiment 2

[0029] First prepare a mixture of sodium hydroxide: urea: pure water = 8:4:88 (mass ratio), add 1.2g of chitin to 30g of the above mixture and mix well at -30 o Freeze at C for 36 hours and stir in time, after thawing, store in 2-8 o C fully stirred to obtain a 4wt% homogeneous chitin aqueous solution. Add a solution containing 2.8g of chloroacetic acid, 1.4g of sodium hydroxide, 0.5g of urea and 10mL of pure water to the homogeneous chitin aqueous solution. o Stir the reaction at C for 6h, 14~16 o The reaction was stirred for 24 hours at C, and the reaction solution was controlled to be a homogeneous transparent system. Use 1M hydrochloric acid to adjust the pH value to 7.5, use 1L acetone to precipitate, filter and wash the precipitate with 80% (v / v) ethanol aqueous solution to remove small molecules such as urea and salts, and dry at 50°C to obtain powdered carboxy-modified carapace element, the yield is 89%. The product is then dissolved in water, dialyzed to remove a ...

Embodiment 3

[0031] First prepare a mixture of sodium hydroxide: urea: pure water = 11:4:85 (mass ratio), add 1.0g of chitin to 100g of the above mixture and mix well at -30 o Freeze at C for 24 hours and stir in time, after thawing, store in 1-5 o C under full stirring to obtain a 1wt% homogeneous chitin aqueous solution. Add a mixed solution containing 2.33g of chloroacetic acid, 1.5g of sodium hydroxide, 0.45g of urea and 10mL of pure water into the homogeneous chitin aqueous solution. o Stir the reaction at C for 6h, then at 14~16 o The reaction was stirred for 12 hours at C, and the reaction solution was controlled to be a homogeneous transparent system. Use 1M hydrochloric acid solution to adjust the pH value to 7.2, use 1L acetone to precipitate, filter and wash with ethanol / water (80%, v / v) to remove small molecules such as urea and salts in the precipitate, and dry at 50°C to obtain powder carboxyl-modified chitin. The product was analyzed by proton nuclear magnetic spectrum t...

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Abstract

The invention discloses a method for homogeneous preparation of carboxyl chitin with a low deacetylation degree and an application of carboxyl chitin. Firstly, chitin is added into a mixed aqueous solution of sodium hydroxide and urea to obtain a homogeneous chitin aqueous solution, then an aqueous solution containing a carboxyl reagent is added into the homogeneous chitin aqueous solution for stirring reaction, and the carboxyl chitin with the low deacetylation degree is obtained after posttreatment. The method has the advantages of simple preparation process, uniform and controllable substitution degree of the product, high yield, and mild reaction condition, is an environmentally friendly and green technology, and is conducive to large-scale industrialized production; the chitin is basically not degraded, and a few of prepared carboxyl chitin with the low deacetylation degree has pH sensitivity and temperature sensitivity and can be used as drug carrier materials. The prepared water-soluble high-viscosity product is obtained by modifying natural raw materials, is cheap and biodegradable, has functions similar to functions of natural moisturizing conditioner hyaluronic acid, and can be widely used in cosmetics, medicines, health care, feature beautifying, textiles, food processing, environmental protection and other fields.

Description

technical field [0001] The invention belongs to the field of material science, and relates to a method for homogeneously preparing carboxychitin with a low degree of deacetylation and an application thereof. Background technique [0002] Chitin is extracted from the shells of crustaceans and the cell walls of fungi and algae. It is the second largest renewable natural polymer after cellulose and has a linear structure. Chitin and its derivatives have very good biocompatibility, biodegradability, low toxicity and various biological activities, and have great research and application value. However, due to the high crystallinity of chitin itself due to hydrogen bonding, it is insoluble in water, low concentration of acid and alkali, and insoluble in common organic solvents, which limits its research, development and application. [0003] After the reaction of carboxymethyl chitin, it is easily soluble in water [Zhang Qiuhua et al., Preparation of water-soluble carboxymethyl c...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B37/08C08J9/28C08J3/12A61K47/36
Inventor 蒋序林刘慧杨奇志卓仁禧
Owner WUHAN UNIV
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