A kind of preparation method of low molecular weight chitosan

A low molecular weight, chitosan technology, applied in the field of chitosan degradation, can solve the problems of molecular weight distribution, high degradation efficiency, narrow active amino content, and low active amino content, so as to improve degradation efficiency, energy utilization rate, and color Pure whiteness, activity-enhancing effect

Active Publication Date: 2018-10-02
SHANGHAI YUKING WATER SOLUBLE MATERIAL TECH
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Problems solved by technology

[0009] The purpose of the present invention is to provide a kind of preparation method of low molecular weight chitosan, to overcome prior art when preparing low molecular weight chitosan, active amino content is low, yield is not high, the problems such as molecular weight distribution are wider, can guarantee preparation The low molecular weight chitosan has high active amino content and narrow molecular weight distribution and high degradation efficiency, high yield and low cost

Method used

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  • A kind of preparation method of low molecular weight chitosan

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Effect test

Embodiment 1

[0057] Dissolve 8 g of chitosan with a molecular weight of 1.4 million and a degree of deacetylation of 75% in glacial acetic acid solution with a pH value of 3.0 in 100 ml, stir until it dissolves evenly, and then use sodium bicarbonate to adjust the pH value to 9 to obtain a uniform and stable chitosan Chitosan suspension; add 3.2g benzyloxycarbonyl chloride to the above suspension, control the reaction temperature not to exceed 15°C, react for two hours, then add glacial acetic acid solution to adjust the pH value of the system to 3.0, so that the shell The polysaccharide is completely dissolved to obtain a chitosan solution that has completed amino protection.

[0058] Add 1.92g of hydrogen peroxide to the above-mentioned chitosan solution that has completed the amino protection, under the condition of frequency 30KHz, power 25W, ultrasonic at room temperature for 20min, then transfer to a water bath to heat and degrade, control the reaction temperature to 55°C, and add 1.2...

Embodiment 2

[0063] Dissolve 10g of chitosan with a molecular weight of 1.5 million and a degree of deacetylation of 80% in 100ml of citric acid solution with a pH value of 4.5, stir and dissolve evenly, and adjust the pH value to 8 with sodium bicarbonate to obtain a uniform and stable shell Polysaccharide suspension: add 7.0g tert-butoxycarbonyl chloride to the above suspension, control the reaction temperature not to exceed 15°C, react for two hours, then add citric acid solution to adjust the pH value of the system to 4.5, so that the shell The polysaccharide is completely dissolved to obtain a chitosan solution that has completed amino protection.

[0064] Add 2.1g of hydrogen peroxide to the chitosan solution that has completed the amino protection above, at a frequency of 30KHz and a power of 35W, ultrasonicate at room temperature for 30min, then transfer to a water bath for heating and degradation, control the reaction temperature to 60°C, and add 0.9g Hydrogen peroxide, reaction t...

Embodiment 3

[0069] Dissolve 13g of chitosan with a molecular weight of 1.6 million and a degree of deacetylation of 90% in 100ml of citric acid solution with a pH value of 5.0, stir and dissolve evenly, and adjust the pH value to 10 with sodium bicarbonate to obtain a uniform and stable shell Polysaccharide suspension: add 7.8g trimethylsilylethoxycarbonyl chloride to the above suspension, react for two hours, control the reaction temperature below 15°C, and then add citric acid solution to adjust the pH value of the system to 5.0, To make the chitosan dissolve completely, the chitosan solution having completed the amino protection is obtained.

[0070] Add 5.2g of hydrogen peroxide to the above amino-protected chitosan solution, ultrasonicate at room temperature for 35min at a frequency of 40KHz and power of 40W, then transfer to a water bath for heating and degradation, control the reaction temperature at 60°C, and add 3.25g of peroxide Hydrogen, reacted for 1.5 hours.

[0071] After t...

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Abstract

The invention provides a preparation method of low-molecular weight chitosan. The method comprises a step of degrading high-molecular weight chitosan, wherein before degrading the high-molecular weight chitosan, a protecting group is introduced to perform amino protection on chitosan; and the protecting group is one of carbobenzoxy, t-butylcarbonyl, trimethyl silicon ethoxycarbonyl and fluorenylmethyloxycarbonyl. The high-molecular weight chitosan is degraded through the technology combining short-time ultrasonic and hydrogen peroxide chemical degradation. By adopting the method provided by the invention, the prepared low-molecular weight chitosan has relatively high content of active amino, the molecular weight is low, the molecular weight distribution is relatively narrow, the color is pure white, the yield is high, and the application value is greatly increased; by combining ultrasonic pretreatment and chemical oxidation, the degradation efficiency and the energy utilization rate are improved, and the production cost is greatly reduced; and moreover, the technology is simple and convenient to operate, the reaction is easy to control, the reaction conditions are mild, and the method is suitable for large-scale industrial production.

Description

technical field [0001] The invention belongs to the technical field of chitosan degradation, and in particular relates to a preparation method of low molecular weight chitosan. Background technique [0002] Chitin is a six-carbon polymer similar to plant fibers. It is the only biodegradable cationic polymer material that exists in nature. It is widely found in crustaceans such as shrimps and crabs, as well as insects, algae and In bacteria, it is also called animal element, chitin, chitin or chitin. Due to its chemical inactivity and poor solubility, chitin has very limited direct applications. Chitosan (Chitosan), which is obtained after deacetylation of chitin, has greatly changed its chemical properties due to the presence of amino active groups in its molecular structure. It is the only natural alkaline polysaccharide found so far and has many unique properties. It also has the advantages of non-toxicity, good biocompatibility and easy degradation. However, the hydrog...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C08B37/08
CPCC08B37/003
Inventor 王宇朱广东
Owner SHANGHAI YUKING WATER SOLUBLE MATERIAL TECH
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