Method for deacetylation of chitin based on solid-phase shear milling technique for ultrafine grinding at room temperature

Abstract

This invention provides a method for the deacetylation of chitin at room temperature using solid-phase shear milling technology. The method involves mixing 80-90 parts by weight of chitin and 10-20 parts by weight of a solid alkali, adding the mixture to a disc-type solid-phase mechanochemical reactor for co-milling. After milling, the mixed powder is collected, washed to remove residual solid alkali, and then dried to obtain activated chitin powder. This invention discovers that under solid-phase shear milling conditions, the co-milling effect of chitin and a small amount of solid alkali can significantly increase the degree of deacetylation of chitin in a very short time, providing a green and simple processing method for the deacetylation of chitin to prepare chitosan.

Description

Technical Field

[0001] This invention belongs to the field of chitin deacetylation technology, and relates to a method for chitin deacetylation based on solid-phase shear milling technology for room temperature ultrafine grinding, particularly for the preparation using the mechanochemical reactor disclosed in Chinese authorized invention patent ZL 95111258.9. Background Technology

[0002] Biomass materials are renewable, biodegradable, and abundant, making them a valuable natural resource worthy of vigorous development and utilization. Common biomass materials include cellulose, lignin, starch, and chitin. The full and effective utilization of these biomass materials is of great significance in addressing current resource scarcity and environmental pollution issues.

[0003] Among biomass materials, chitin is abundant in the natural environment, mainly derived from the shells of crustaceans, and is the most abundant nitrogen-containing organic compound on Earth. Nature biosynthesizes approximately 10-100 billion tons of chitin annually, making it the second largest natural polymer on Earth after cellulose, with applications in numerous fields such as industry, medicine, and clothing.

[0004] Chitosan is obtained by removing acetyl side groups from the chitin molecular chain. Chitosan is soluble in dilute acids, and its abundant amino groups endow it with excellent functionality, making it widely used in the biomedical field.

[0005] However, the traditional technologies used in the chemical industry to prepare chitosan mostly involve treating chitin with a strongly alkaline solution at high temperatures. The waste solvents generated during this process cause significant environmental damage and are inconsistent with current green and sustainable development principles. Furthermore, the strong alkali used in the production process must reach a certain concentration to treat the chitin, and alkali loss occurs as a result. Calculations show that the amount of alkali used in chitosan preparation from chitin is typically five times the weight of the chitin itself, accounting for a major portion of the current raw material cost.

[0006] Therefore, reducing the amount of alkali used has become a major focus for cost reduction and efficiency improvement in chitosan production. A search revealed a Chinese invention patent, "A Clean Production Method for High Deacetylation Chitosan" (CN109467617B), which discloses a method for efficiently preparing high deacetylation chitosan under relatively low alkali concentration conditions. This method uses alkali solution to pretreat chitin and utilizes the negative pressure environment of a vacuum reactor for the deacetylation reaction. In this patent, the amount of alkali used is 0.5 to 4 times the weight of chitin, but this requires a negative pressure environment for the reaction, resulting in relatively high equipment costs and operational requirements. Furthermore, the reaction time still requires 1.5 to 7 hours, indicating a still excessively long production cycle. Summary of the Invention

[0007] To address the problems in the prior art, this invention provides a method for the deacetylation of chitin based on solid-phase shear milling technology for room-temperature ultrafine grinding. It has been discovered that under solid-phase shear milling conditions, the co-milling effect of chitin and a small amount of solid alkali enables room-temperature ultrafine grinding of chitin, significantly increasing the degree of deacetylation of chitin in a very short time. This provides a green and simple processing method for the deacetylation of chitin to prepare chitosan powder.

[0008] To achieve the above objectives, the present invention employs a technical solution consisting of the following technical measures.

[0009] This invention provides a method for deacetylation of chitin based on room temperature ultrafine grinding using solid-phase shear milling technology, mainly comprising the following steps:

[0010] (1) The raw materials, mainly comprising the following components, are mixed and prepared as a mixture by mass parts:

[0011] 80-90 parts of chitin

[0012] 10-20 parts of solid alkali,

[0013] Of these, 100 portions consisted of chitin and solid alkalis.

[0014] (2) The mixture obtained in step (1) is added to a grinding disc type solid phase mechanical chemical reactor for co-grinding and pulverization. After grinding is completed, the mixed powder is collected. The process parameters of the grinding disc type solid phase mechanical chemical reactor are: grinding pressure of 4-6 MPa, grinding disc surface temperature controlled by circulating cooling liquid at 0-10℃, cyclic grinding 1-10 times, and grinding disc speed of 40-60 rpm.

[0015] (3) After washing to remove residual solid alkali from the mixed powder obtained in step (2), the powder is dried to obtain activated chitin powder.

[0016] It should be noted that the degree of deacetylation of the activated chitin powder obtained in step (3) varies depending on the process parameters of the millstone-type solid-phase chemical reactor. When the degree of deacetylation of the activated chitin powder is above 50%, it can be used as chitosan based on common knowledge in the field.

[0017] In this document, the chitin mentioned in step (1) is generally a commercially available chitin raw material in the art, and can be a conventional industrial-grade chitin raw material, usually in sheet form.

[0018] In this article, the solid alkali mentioned in step (1) is a strong alkali in a conventional solid form in the chemical industry. Those skilled in the art can select a suitable strong alkali based on common knowledge in the chemical industry. It is preferred to use conventional alkalis in the preparation of chitosan in existing process technologies, such as solid sodium hydroxide and solid potassium hydroxide.

[0019] In one of the technical solutions, in order to further improve the mixing effect of the mixture obtained in step (1), the solid alkali is a powder or is pulverized into powder through pretreatment.

[0020] In this paper, the millstone-type solid-phase mechanochemical reactor mentioned in step (2) is the mechanochemical reactor disclosed in the prior authorized patent ZL 95111258.9 of the applicant of this invention.

[0021] In this paper, the actual operation of the cyclic milling process in step (2) is to mill the mixture in a disc-type mechanical chemical reactor, collect the product at the discharge end, and then put it back into the disc-type mechanical chemical reactor for milling. The above process is considered as one cycle of milling.

[0022] In this document, the grinding disc surface temperature in step (2) is controlled by introducing a circulating cooling liquid, which is water, ethylene glycol, or glycerin.

[0023] In this article, the mixed powder described in step (3) is washed to remove residual solid alkali. In order to take advantage of the solubility of solid alkali for washing and removal, the washing liquid used is usually water.

[0024] In one technical solution, the mixed powder in step (3) is washed to remove residual solid alkali, specifically by water washing. The aqueous solution containing the dissolved solid alkali is then recovered as a recycled alkali solution. Generally, the recycled alkali solution can be rendered harmless or reused by conventional alkali recovery treatment. It should be noted that alkali recovery treatment is a well-established and mature technology, and those skilled in the art can choose a suitable method. Furthermore, since the recycled alkali solution has low impurity content and virtually no other harmful substances, it is preferable to reuse it by conventional alkali recovery treatment to obtain solid alkali, which can then be reused as a raw material for solid alkali in this invention.

[0025] This invention originates from the inventors' use of solid-phase shear milling technology to activate chitin, allowing the activated chitin powder to be used as an intermediate product for functional group modification, or to introduce other monomers onto the chitin matrix through graft copolymerization, or to achieve composite formation of chitin with other polymers through blending modification. During the aforementioned experimental exploration, it was accidentally discovered that the chitin powder prepared under co-milling conditions with only a small amount of solid alkali exhibited a high degree of deacetylation, thus serving as an effective, green, and simple method for preparing chitosan.

[0026] The key feature of this invention is that the amount of alkali used in the entire preparation process is only 0.1 to 0.2 times that of chitosan, significantly reducing the preparation cost. Furthermore, the residual solid alkali after washing can be recycled and reused, further reducing costs. In addition, the production cycle of the entire preparation method is significantly shorter than traditional technologies. Tests show that the processing time for five cycles of milling is approximately 30 to 60 minutes. Moreover, the entire preparation process requires no additional processing conditions such as heating or negative pressure, making the operation simple.

[0027] However, it should be noted again that the degree of deacetylation of the activated chitin powder obtained in step (3) varies depending on the process parameters of the milling disc type solid phase mechanochemical reactor. Based on different preparation purposes, those skilled in the art can increase the degree of deacetylation by increasing the number of cyclic milling cycles.

[0028] In one preferred embodiment, to improve the degree of deacetylation of the activated chitin powder obtained in step (3) and reduce costs, the cyclic milling in step (2) is performed 4 to 5 times. Comparative experiments revealed that after more than 5 cyclic milling cycles, the degree of deacetylation of the activated chitin powder obtained from the milling process did not change significantly.

[0029] In one preferred embodiment, in order to make the degree of deacetylation of the activated chitin powder obtained in step (3) reach at least 50%, the cyclic milling in step (2) is performed 4 to 5 times, and the raw material in step (1) also includes 50 to 100 parts of conventional soluble sodium salt powder or conventional soluble potassium salt powder, such as sodium chloride or potassium chloride.

[0030] It is worth noting that, in the technical solution provided by the present invention, after different cycles of milling, the interplanar spacing of the activated chitin powder did not change significantly, indicating that under the process parameters of the grinding disc type solid-phase mechanochemical reactor provided by the present invention, the ultrafine grinding of chitin can be achieved without affecting its performance.

[0031] In this document, the mixing, washing, and drying processes all follow conventional principles in chemical processes, and those skilled in the art can perform the specific operations based on common knowledge.

[0032] The present invention has the following beneficial effects:

[0033] 1. This invention provides a method for deacetylation of chitin based on solid-phase shear milling technology for room temperature ultrafine grinding. It can significantly improve the degree of deacetylation of chitin in a very short time under very small alkali conditions and simultaneously achieve room temperature ultrafine grinding of chitin, providing a green and simple processing method for the deacetylation of chitin to prepare chitosan.

[0034] 2. The present invention provides a method for deacetylation of chitin based on solid-phase shear milling technology for room temperature ultrafine grinding. The entire preparation process does not require additional processing conditions such as heating or negative pressure, and the preparation operation is extremely simple.

[0035] 3. The chitin deacetylation method based on solid-phase shear milling technology for room temperature ultrafine grinding provided by the present invention, through analysis of the interplanar spacing of the prepared activated chitin powder, shows that under the process parameters of the grinding disc type solid-phase mechanochemical reactor provided by the present invention, the ultrafine grinding of chitin can be achieved without affecting its performance. Attached Figure Description

[0036] Figure 1 These are comparative photographs and electron microscope images of chitin before and after grinding in Example 3 of the present invention. Among them, (a) is an electron microscope image of chitin before grinding in Example 3; (b) is an electron microscope image of chitin after grinding in Example 3.

[0037] Figure 2 This document presents high-resolution TEM images and interplanar spacing comparisons of chitin before, during, and after cyclic milling in Example 3 of the present invention. Specifically, (a) is an electron microscope image and interplanar spacing data of chitin before cyclic milling in Example 3; (b) is an electron microscope image and interplanar spacing data of chitin after one cyclic milling cycle in Example 3; (c) is an electron microscope image and interplanar spacing data of chitin after five cyclic milling cycles in Example 3; and (d) is an electron microscope image and interplanar spacing data of chitin after ten cyclic milling cycles in Example 3.

[0038] Figure 3 The bar charts show the degree of deacetylation of chitin powder obtained in Examples 1-2 and Comparative Example 1 of this invention. Detailed Implementation

[0039] To further understand the present invention, preferred embodiments are described below with reference to examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims. Those skilled in the art can refer to the content of this document to appropriately improve the process parameters. In particular, it should be noted that all similar substitutions and modifications are obvious to those skilled in the art and are considered to be included within the scope of the present invention. The methods and applications of the present invention have been described through preferred embodiments, and those skilled in the art can obviously make modifications or appropriate changes and combinations to the methods and applications described herein without departing from the content, spirit and scope of the present invention to realize and apply the technology of the present invention. Although it is believed that those skilled in the art will fully understand the following terms, the following definitions are set forth to help illustrate the subject matter disclosed in the present invention.

[0040] This invention provides a method for deacetylation of chitin based on room temperature ultrafine grinding using solid-phase shear milling technology, mainly comprising the following steps:

[0041] (1) The raw materials, mainly comprising the following components, are mixed and prepared as a mixture by mass parts:

[0042] 80-90 parts of chitin

[0043] 10-20 parts of solid alkali,

[0044] Of these, 100 portions consisted of chitin and solid alkalis.

[0045] (2) The mixture obtained in step (1) is added to a grinding disc type solid phase mechanical chemical reactor for co-grinding and pulverization. After grinding is completed, the mixed powder is collected. The process parameters of the grinding disc type solid phase mechanical chemical reactor are: grinding pressure of 4-6 MPa, grinding disc surface temperature controlled by circulating cooling liquid at 0-10℃, cyclic grinding 1-10 times, and grinding disc speed of 40-60 rpm.

[0046] (3) After washing to remove residual solid alkali from the mixed powder obtained in step (2), the powder is dried to obtain activated chitin powder.

[0047] It should be noted that the degree of deacetylation of the activated chitin powder obtained in step (3) varies depending on the process parameters of the millstone-type solid-phase chemical reactor. When the degree of deacetylation of the activated chitin powder is above 50%, it can be used as chitosan based on common knowledge in the field.

[0048] In this document, the chitin mentioned in step (1) is generally a commercially available chitin raw material in the art, preferably a conventional industrial-grade chitin raw material, and in one embodiment, commercially available chitin sheets are selected.

[0049] In this article, the solid alkali mentioned in step (1) is a strong alkali in a conventional solid form in the chemical industry. Those skilled in the art can select a suitable strong alkali based on common knowledge in the chemical industry. In one embodiment, it is preferably a conventional alkali used in the preparation of chitosan in existing process technologies, such as solid sodium hydroxide or solid potassium hydroxide.

[0050] In one embodiment, to further improve the mixing effect of the mixture obtained in step (1), the solid alkali is a powder or is pulverized into powder through pretreatment.

[0051] In one embodiment, the chitin in step (1) is 80 to 90 parts, for example 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90 parts or any range or point value therebetween; the solid alkali in step (1) is 10 to 20 parts, for example 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts or any range or point value therebetween.

[0052] In this paper, the millstone-type solid-phase mechanochemical reactor mentioned in step (2) is the mechanochemical reactor disclosed in the prior authorized patent ZL 95111258.9 of the applicant of this invention.

[0053] In this paper, the actual operation of the cyclic milling process in step (2) is to mill the mixture in a disc-type mechanical chemical reactor, collect the product at the discharge end, and then put it back into the disc-type mechanical chemical reactor for milling. The above process is considered as one cycle of milling.

[0054] In one embodiment, the temperature of the grinding disc surface in step (2) is controlled by introducing a circulating cooling liquid, which is water, ethylene glycol or glycerin.

[0055] In one embodiment, the process parameters of the grinding disc type solid-phase mechanochemical reactor in step (2) are as follows: the grinding pressure is 4 to 6 MPa, for example, 4 MPa, 4.5 MPa, 5 MPa, 5.5 MPa, 6 MPa or any range or point value between them; the grinding disc surface temperature is controlled by introducing circulating cooling liquid to be 0 to 10°C, for example, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 6°C, 7°C, 8°C, 9°C, 10°C or any range or point value between them; the grinding is cyclically ground 1 to 10 times, for example, once, twice, three times, four times, five times, six times, seven times, eight times, nine times or ten times; the grinding disc rotation speed is 40 to 60 rpm, for example, 40 rpm, 45 rpm, 50 rpm, 55 rpm, 60 rpm or any range or point value between them.

[0056] In this article, the mixed powder described in step (3) is washed to remove residual solid alkali. In order to take advantage of the solubility of solid alkali for washing and removal, the washing liquid used is usually water.

[0057] In one embodiment, the mixed powder in step (3) is washed to remove residual solid alkali, specifically by water washing. The aqueous solution containing the dissolved solid alkali is then recovered as a recycled alkali solution. Generally, the recycled alkali solution can be rendered harmless or reused by conventional alkali recovery treatment. It should be noted that alkali recovery treatment is a well-established and mature technology, and those skilled in the art can choose a suitable method. Furthermore, since the recycled alkali solution has low impurity content and virtually no other harmful substances, it is more preferable to use conventional alkali recovery treatment to reprocess solid alkali, which can then be reused as a raw material for solid alkali in this invention.

[0058] This invention originates from the inventors' use of solid-phase shear milling technology to activate chitin, allowing the activated chitin powder to be used as an intermediate product for functional group modification, or to introduce other monomers onto the chitin matrix through graft copolymerization, or to achieve composite formation of chitin with other polymers through blending modification. During the aforementioned experimental exploration, it was accidentally discovered that the chitin powder prepared under co-milling conditions with only a small amount of solid alkali exhibited a high degree of deacetylation, thus serving as an effective, green, and simple method for preparing chitosan.

[0059] The key feature of this invention is that the amount of alkali used in the entire preparation process is only 0.1 to 0.2 times that of chitosan, significantly reducing the preparation cost. Furthermore, the residual solid alkali after washing can be recycled and reused, further reducing costs. In addition, the production cycle of the entire preparation method is significantly shorter than traditional technologies. Tests show that the processing time for five cycles of milling is approximately 30 to 60 minutes. Moreover, the entire preparation process requires no additional processing conditions such as heating or negative pressure, making the operation simple.

[0060] However, it should be noted again that the degree of deacetylation of the activated chitin powder obtained in step (3) varies depending on the process parameters of the milling disc type solid phase mechanochemical reactor. Based on different preparation purposes, those skilled in the art can increase the degree of deacetylation by increasing the number of cyclic milling cycles.

[0061] In one preferred embodiment, in order to improve the degree of deacetylation of the activated chitin powder obtained in step (3) and reduce costs, the cyclic milling in step (2) is performed 4 to 5 times. Comparative experiments have shown that after more than 5 cyclic milling cycles, the degree of deacetylation of the activated chitin powder obtained by milling does not change significantly.

[0062] In one preferred embodiment, in order to make the degree of deacetylation of the activated chitin powder obtained in step (3) reach at least 50%, the cyclic milling in step (2) is performed 4 to 5 times, and the raw material in step (1) also includes 50 to 100 parts of conventional soluble sodium salt powder or conventional soluble potassium salt powder, such as sodium chloride or potassium chloride.

[0063] It is worth noting that, in the technical solution provided by the present invention, after different cycles of milling, the interplanar spacing of the activated chitin powder did not change significantly, indicating that under the process parameters of the grinding disc type solid-phase mechanochemical reactor provided by the present invention, the ultrafine grinding of chitin can be achieved without affecting its performance.

[0064] In this document, the mixing, washing, and drying processes all follow conventional principles in chemical processes, and those skilled in the art can perform the specific operations based on common knowledge.

[0065] The present application will be further explained in detail below with reference to embodiments. However, those skilled in the art should understand that these embodiments are provided for illustrative purposes only and are not intended to limit the present application.

[0066] Example

[0067] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of this application. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all commercially available conventional products. This application should not be construed as being limited to the specific embodiments described.

[0068] 1. Raw materials

[0069] Chitosan, Zhejiang Jinke Pharmaceutical Co., Ltd.;

[0070] Sodium hydroxide, Fuchen Chemical, analytical grade;

[0071] Sodium chloride, Fuchen Chemical, analytical grade.

[0072] Example 1

[0073] This embodiment provides a method for deacetylation of chitin based on room temperature ultrafine grinding using solid-phase shear milling technology, mainly including the following steps:

[0074] (1) The following raw materials, by mass parts, are mixed and prepared as a mixture:

[0075] 85 parts of chitosan

[0076] 15 parts sodium hydroxide,

[0077] 85 parts sodium chloride;

[0078] (2) The mixture obtained in step (1) is added to a grinding disc type solid-state mechanical chemical reactor for co-grinding and pulverization. After grinding is completed, the mixed powder is collected. The process parameters of the grinding disc type solid-state mechanical chemical reactor are: grinding pressure is 4MPa, grinding disc surface temperature is controlled at 10℃ by introducing circulating cooling liquid, grinding is 5 times, and grinding disc speed is 50 rpm.

[0079] (3) After washing to remove residual sodium hydroxide and sodium chloride, the mixed powder obtained in step (2) is dried to obtain activated chitin powder. The degree of deacetylation of the activated chitin powder is 51.9%, which can be regarded as chitosan.

[0080] Example 2

[0081] This embodiment provides a method for deacetylation of chitin based on room temperature ultrafine grinding using solid-phase shear milling technology, mainly including the following steps:

[0082] (1) The following raw materials, by mass parts, are mixed and prepared as a mixture:

[0083] 85 parts of chitosan

[0084] 15 parts sodium hydroxide;

[0085] (2) The mixture obtained in step (1) is added to a grinding disc type solid-state mechanical chemical reactor for co-grinding and pulverization. After grinding is completed, the mixed powder is collected. The process parameters of the grinding disc type solid-state mechanical chemical reactor are: grinding pressure is 4MPa, grinding disc surface temperature is controlled at 10℃ by introducing circulating cooling liquid, grinding is 5 times, and grinding disc speed is 50 rpm.

[0086] (3) After washing to remove residual sodium hydroxide and sodium chloride, the mixed powder obtained in step (2) is dried to obtain activated chitin powder. The degree of deacetylation of the activated chitin powder is 39.3%.

[0087] Example 3

[0088] This embodiment provides a method for deacetylation of chitin based on room temperature ultrafine grinding using solid-phase shear milling technology, mainly including the following steps:

[0089] (1) The following raw materials, by mass parts, are mixed and prepared as a mixture:

[0090] 85 parts of chitosan

[0091] 15 parts sodium hydroxide;

[0092] (2) The mixture obtained in step (1) is added to a grinding disc type solid-state mechanical chemical reactor for co-grinding and pulverization. After grinding is completed, the mixed powder is collected. The process parameters of the grinding disc type solid-state mechanical chemical reactor are: grinding pressure is 4MPa, grinding disc surface temperature is controlled at 10℃ by introducing circulating cooling liquid, grinding is repeated 10 times, and grinding disc speed is 50 rpm.

[0093] (3) After washing to remove residual sodium hydroxide and sodium chloride, the mixed powder obtained in step (2) is dried to obtain activated chitin powder. The degree of deacetylation of the activated chitin powder is close to that obtained in Example 2.

[0094] Comparative Example 1

[0095] This comparative example provides a method for ultrafine pulverization of chitin alone at room temperature using solid-phase shear milling technology, mainly including the following steps:

[0096] (1) Prepare the following raw materials by mass parts:

[0097] 85 parts of chitosan;

[0098] (2) Add the chitin from step (1) to a grinding disc type solid phase chemical reactor for grinding and pulverizing. After grinding is completed, collect the chitin powder. The process parameters of the grinding disc type solid phase chemical reactor are: grinding pressure is 4 MPa, grinding disc surface temperature is controlled at 10℃ by introducing circulating cooling liquid, grinding is repeated 5 times, and grinding disc speed is 50 rpm.

[0099] (3) The chitin powder obtained in step (2) is dried to obtain the chitin powder after milling. The degree of deacetylation of the milled chitin powder is 23.2%, which is close to that of the unmilled chitin powder (the degree of deacetylation of the purchased chitin is about 20%).

[0100] 2. Testing Methods

[0101] ① Scanning electron microscope

[0102] The morphology and structure of the samples were observed using an Inspect F scanning electron microscope manufactured by FEI GmbH in the Netherlands, with an accelerating voltage of 20 kV.

[0103] ② Transmission electron microscope

[0104] The morphology and structure of the samples were observed using a FEI Tecnai G2 F20 field emission transmission electron microscope manufactured by FEI Corporation, with an accelerating voltage of 200 kV.

[0105] ③ Deacetylation test

[0106] The degree of deacetylation of chitin was determined using a Nicolet 6700FT-IR infrared spectrometer.

[0107] Test results are as follows Figures 1-3 As shown, the present invention provides a method for deacetylation of chitin based on solid-phase shear milling technology for room-temperature ultrafine grinding. This method can significantly improve the degree of deacetylation of chitin and simultaneously achieve room-temperature ultrafine grinding of chitin under conditions of very small alkali dosage and in a very short time. This provides a green and simple processing method for the deacetylation of chitin to prepare chitosan. Analysis of the interplanar spacing of the prepared chitin powder shows that the change in interplanar spacing is very small, indicating that under the process parameters of the grinding disc type solid-phase mechanochemical reactor provided by the present invention, the ultrafine grinding of chitin is achieved without affecting its performance.

[0108] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for deacetylation of chitin based on room temperature ultrafine grinding using solid-phase shear milling technology, characterized in that... Includes the following steps: (1) The raw materials comprising the following components are mixed and prepared as a mixture by mass parts: 80-90 parts of chitin 10-20 parts of solid alkali Sodium chloride 50-100 parts, Among them, chitin and solid alkaloids totaled 100 parts; (2) The mixture obtained in step (1) is added to a grinding disc type solid phase mechanical chemical reactor for co-grinding and pulverization. After grinding is completed, the mixed powder is collected. The process parameters of the grinding disc type solid phase mechanical chemical reactor are: grinding pressure is 4~6MPa, grinding disc surface temperature is controlled by circulating cooling liquid to 0~10℃, grinding is repeated 1~10 times, and grinding disc speed is 40~60 rpm. (3) After washing to remove residual solid alkali from the mixed powder obtained in step (2), the powder is dried to obtain activated chitin powder.

2. The chitin deacetylation method according to claim 1, characterized in that: The solid alkali mentioned in step (1) is solid sodium hydroxide or solid potassium hydroxide.

3. The chitin deacetylation method according to claim 1, characterized in that: In step (3), the mixed powder is washed to remove residual solid alkali, and the washing liquid used is water.

4. The chitin deacetylation method according to claim 1, characterized in that: In step (3), the mixed powder is washed to remove residual solid alkali. Specifically, water washing is used to remove residual solid alkali, and the aqueous solution containing dissolved solid alkali is recovered as a recovered alkali solution.

5. The chitin deacetylation method according to claim 1, characterized in that: The cyclic grinding in step (2) is repeated 4 to 5 times.

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