Preparation method of N-acetyl blue and application of prepared N-acetyl blue in fabric dyeing

Abstract

The invention discloses a preparation method of N-acetyl blue and application of the prepared N-acetyl blue in fabric dyeing, and relates to the technical field of compound synthesis. According to the preparation method of the N-acetyl blue, H2SO4 and aluminum chloride are adopted as a composite catalyst to catalyze N, N-dimethyl formamide; according to the present invention, the N, N '-diacetyl blue hydrolysis reaction is performed, such that the potential barrier of the N, N'-diacetyl blue hydrolysis reaction can be reduced so as to directionally remove one acetyl in the molecule to generate the N-acetyl blue, the product with the yield of more than 53% and the purity of more than 78% can be obtained by using the preparation method, and the purity and the reaction yield are excellent.

Description

Technical Field

[0001] This invention relates to the field of compound synthesis technology, specifically to a method for preparing N-acetylglucosamine and the application of the prepared N-acetylglucosamine in fabric dyeing. Background Technology

[0002] Blue is one of the three primary colors of light, and its short wavelength makes it one of the colors to which the human eye is most sensitive. This has led to the widespread application of blue pigments. Currently, there are many types of blue dyes on the market, most of which are synthetic dyes, such as synthetic indigo, phthalocyanine blue, and acid blue. These dyes vary in hue, fastness, and performance. However, generally speaking, most dyes can only meet one standard of colorfastness, making it difficult to simultaneously satisfy multiple colorfastness requirements. For example, reactive blue Turquoise Blue G has good washing fastness but poor rubbing fastness.

[0003] Chinese patent CN118756508A discloses N-acetylglucosamine as a dye obtained by structural modification of galbanum as the parent nucleus, which exhibits excellent wash fastness and rubbing fastness. However, the current preparation method of N-acetylglucosamine mainly involves microbial fermentation, which is relatively complex and time-consuming; while chemical methods that directly modify the galbanum parent nucleus inevitably generate N,N'-diacetylgalbanum as a byproduct, affecting the purity of N-acetylglucosamine. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for preparing N-acetylglucosamine and the application of the prepared N-acetylglucosamine in fabric dyeing.

[0005] The above-mentioned objective of this invention is achieved through the following technical solution: A method for preparing N-acetylglucosamine blue includes the following steps: N,N'-diacetyl styrax was dispersed in water to obtain a reaction dispersion. A composite catalyst was added to cause the N,N'-diacetyl styrax to undergo a hydrolysis reaction. Then, a terminator was added to terminate the reaction and a solid was precipitated. After solid-liquid separation, the solid was dried to obtain N-acetyl styrax. The composite catalyst includes H2SO4 and aluminum chloride; The terminating agent comprises water at 0-5°C.

[0006] The preparation method of N-acetylglucosamine provided by this invention has the following reaction route: Currently, the preparation methods of N-acetylglucosamine in this field mainly follow a "bottom-up" reaction route, catalyzing the reaction of glutamine and N-acetylglutamine to form a cyclization ring through microbial fermentation. However, the preparation method of N-acetylglucosamine provided by this invention follows a "top-down" route, using N,N'-diacetyllglucosamine as a reactant. By employing a specific catalyst, one acetyl group can be directionally removed from N,N'-diacetyllglucosamine, resulting in a fast reaction rate, high yield, and excellent product purity.

[0007] It should be noted that the reactions in this invention require the catalysis of a specific catalyst to proceed. The inventors of this application unexpectedly discovered that aluminum chloride, as a Lewis acid, exhibits a significantly enhanced catalytic effect in the strongly acidic environment provided by sulfuric acid, enabling it to donate electrons to participate in the activation of the reactants and lower the barrier to the hydrolysis of N,N'-diacetyl chloroquine. To achieve the targeted removal of an acetyl group from the molecule, this invention requires precise control of the mass fraction of each component in the catalyst.

[0008] It should be noted that aluminum chloride in this invention also requires synergistic action with sulfuric acid. Through extensive experimental research, the inventors of this application discovered that other strong acids, such as hydrochloric acid and nitric acid, cannot replace the role of sulfuric acid. Furthermore, combining other strong acids with aluminum chloride fails to catalyze the hydrolysis reaction of N,N'-diacetyl viscose blue. The speculated reason may be that the large amount of halide ions generated when hydrochloric acid and hydrobromic acid dissolve in water are Lewis bases that can donate electrons, easily interacting with Lewis acids and leading to reduced catalytic activity; while nitric acid and perchloric acid have strong oxidizing properties, affecting the reaction tendency of the amide bond in N,N'-diacetyl viscose blue.

[0009] It should be noted that water at 0-5℃ needs to be added as a terminator after the hydrolysis reaction to terminate the reaction by lowering the temperature. Too high a temperature will cause further hydrolysis of N-acetyl blue, while too low a temperature will prevent the precipitation of a solid product with a good morphology.

[0010] Preferably, the mass ratio of H2SO4 to aluminum chloride in the composite catalyst is 1:(1.5-2.5).

[0011] Preferably, the mass ratio of the composite catalyst to N,N'-diacetyl blue is (0.01-0.02):1.

[0012] More preferably, the mass ratio of aluminum chloride to N,N'-diacetyl blue is (0.007-0.012):1.

[0013] Preferably, the hydrolysis reaction is carried out at a temperature of 15-35°C for 1-2 hours.

[0014] More preferably, the hydrolysis reaction is carried out at a temperature of 20-30°C for 1.5 h.

[0015] Preferably, the mass ratio of N,N'-diacetyl blue to water in the reactant dispersion is (0.4-0.6):1.

[0016] Preferably, the mass ratio of the terminator to the reactant dispersion is (2.8-5):1.

[0017] Preferably, the drying temperature is 60-90°C.

[0018] The above preparation method can yield N-acetylglucosamine with a yield of over 53% and a purity of over 78%.

[0019] Biosynthesized N-acetylglucosamine contains a high amount of glucosamine, which can affect the dyeing effect during use. However, the N-acetylglucosamine obtained by the directional hydrolysis of this invention has a high content, which can significantly improve the poor dyeing effect caused by low dye purity.

[0020] The present invention also protects the use of N-acetylass blue prepared by the above method in dyes.

[0021] Compared with the prior art, the present invention has the following beneficial effects: The method for preparing N-acetylglucosamine provided by this invention uses H2SO4 and aluminum chloride as a composite catalyst to catalyze the hydrolysis reaction of N,N'-diacetyllglucosamine. This method can lower the barrier to the hydrolysis reaction of N,N'-diacetyllglucosamine, allowing it to directionally remove one acetyl group from the molecule to generate N-acetylglucosamine. Using the above preparation method, a product with a yield of over 53% and a purity of over 78% can be obtained, exhibiting excellent purity and reaction yield. Attached Figure Description

[0022] Figure 1 The image shows the HPLC chromatogram of N-acetylglucosamine, the product from Example 1.

[0023] Figure 2 The image shows the UV absorption spectrum of N-acetyl blue, the product from Example 1.

[0024] Figure 3 The image shows the MS spectrum of N-acetylglucosamine, the product from Example 1.

[0025] Figure 4 The image shows the 1H NMR spectrum of N-acetylglucosamine, the product from Example 1.

[0026] Figure 5 Figures showing cotton and linen fabrics dyed with N-acetylglucosamine prepared in Example 1. Detailed Implementation

[0027] The present invention will be further described below with reference to specific embodiments, but the embodiments do not limit the present invention in any way. Unless otherwise stated, the raw materials and reagents used in the embodiments of the present invention are conventionally purchased raw materials and reagents. The raw material information used in the embodiments and comparative examples is as follows: N,N'-Diacetyl Blue: Provided by Nanjing Hegu Life Biotechnology Co., Ltd.

[0028] Concentrated sulfuric acid, concentrated hydrochloric acid, concentrated nitric acid, and aluminum chloride were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., and all were reagent grade.

[0029] Example 1 25g of N,N'-diacetyl phthalocyanine powder was weighed and dispersed in 50g of water. Then, 0.125g of H₂SO₄ (added using 98% concentrated sulfuric acid) and 0.25g of aluminum chloride were added to the dispersion. The reaction was carried out at 25°C for 1.5 h. Subsequently, 225g of an ice-water mixture at 3°C ​​was added to terminate the reaction, and a solid precipitated. After solid-liquid separation, the mixture was dried at 80°C to obtain 20.2g of N-acetyl phthalocyanine. The yield was 88%, and the purity was 95%. Figure 1-4 The image shows the characterization spectrum of the product N-acetylglucosamine blue prepared in this embodiment.

[0030] Example 2 25g of N,N'-diacetyl phthalocyanine powder was weighed and dispersed in 62g of water. Then, 0.2g of H₂SO₄ (added using 98% concentrated sulfuric acid) and 0.3g of aluminum chloride were added to the dispersion. The mixture was reacted at 15°C for 2 hours. The reaction solution was then poured into 350g of an ice-water mixture at 0°C to terminate the reaction, and a solid precipitated. After solid-liquid separation, the solid was dried at 90°C to obtain 18.8g of N-acetyl phthalocyanine. The yield was 80%, and the purity was 93%.

[0031] Example 3 25g of N,N'-diacetyl phthalocyanine powder was weighed and dispersed in 42g of water. Then, 0.07g of H₂SO₄ (added using 98% concentrated sulfuric acid) and 0.175g of aluminum chloride were added to the dispersion. The reaction was carried out at 35℃ for 1 h. Subsequently, 325g of an ice-water mixture at 5℃ was added to terminate the reaction, and a solid precipitated. After solid-liquid separation, the mixture was dried at 60℃ to obtain 19.1g of N-acetyl phthalocyanine. The yield was 82%, and the purity was 94%.

[0032] Example 4 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The composite catalyst comprises 0.188 g H₂SO₄ and 0.188 g aluminum chloride. 18.6 g N-acetylglucosamine blue is obtained. Yield: 75%, purity: 88%.

[0033] Example 5 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The composite catalyst comprises 0.094 g H₂SO₄ and 0.281 g aluminum chloride. 22.6 g N-acetylglucosamine blue is obtained. Yield: 81%, purity: 78%.

[0034] Example 6 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The reaction was extended from 1 h at 35℃ to 4 h, yielding 15.9 g of N-acetylglucosamine blue. The yield was 60%, and the purity was 82%.

[0035] Example 7 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The hydrolysis reaction was carried out at 40℃. 14.6 g of N-acetylglucosamine blue was obtained. Yield: 53%, purity: 79%.

[0036] Example 8 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The mass ratio of N,N'-diacetyl violet blue to water in the reactant dispersion was 0.65:1 (the mass of water remained constant). 16.2 g of N-acetyl violet blue was obtained. The yield was 64%, and the purity was 86%.

[0037] Comparative Example 1 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The composite catalyst contains only H2SO4. 1.1 g of N-acetylglucosamine was obtained. Yield <1%, purity 81%.

[0038] Comparative Example 2 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: The composite catalyst contains only aluminum chloride. The product contains no N-acetylglucosamine.

[0039] Comparative Example 3 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: In the composite catalyst, H2SO4 was replaced with an equal mass of HCl (added using 37% concentrated hydrochloric acid as a raw material). No product was detected.

[0040] Comparative Example 4 A method for preparing N-acetylglucosamine blue, wherein the only difference from Example 1 is: In the composite catalyst, H2SO4 was replaced with an equal mass of HNO3 (added using 98% fuming nitric acid as raw material). No product was detected.

[0041] Performance testing I. Product Testing The N-acetylglucosamine product obtained in Example 1 was identified by high performance liquid chromatography, mass spectrometry, and infrared spectroscopy. The relative molecular mass of N,N'-diacetyl-glucosamine was 332.08 g / mol, and the relative molecular mass of N-acetylglucosamine was 290.07 g / mol. The results are shown in the attached figure.

[0042] N-acetylenol and N,N'-diacetyl-lentylenol were used as standards for HPLC analysis to obtain the content of the products obtained in the examples and comparative examples. Chromatographic conditions: mobile phase: gradient elution of methanol and pure water, as shown in the gradient table below: Wavelength 600 nm, flow rate 1.0 mL / min, sample solution: DMSO, injection volume: 10 μL, column temperature 35℃, run time 20 min. Column: Galasil EF-C18M 4.6 mmid × 250 mm L (SN B06211801).

[0043] Product yield = (actual mass × content) / 290) / theoretical yield. 290 is the molecular weight of N-acetylglucosamine. The theoretical yield is 1 mol of N,N'-diacetyl-glucosamine theoretically produces 1 mol of N-acetylglucosamine.

[0044] The test results are shown in Table 2 below: Table 2. As can be seen from Table 3 above, the preparation method provided by the present invention can obtain N-acetyl blue with a yield of over 53% and a purity of over 78%, while the reaction time is less than 2 hours, and the reaction is simple and efficient.

[0045] As can be seen from Examples 1 and 4-5, an inappropriate ratio of sulfuric acid and aluminum chloride in the catalyst can lead to a decrease in catalytic effect.

[0046] According to Examples 1 and 6, an excessively long reaction time can also lead to a decrease in yield, because an excessively long reaction time will cause the target product to react further.

[0047] According to Examples 1 and 7, excessively high reaction temperatures also affect the yield.

[0048] According to Examples 1 and 8, the mass ratio of N,N'-diacetyl blue to water affects its concentration in the reactant dispersion. If the concentration is too high, it will affect the reaction and thus the yield.

[0049] According to Comparative Examples 1-2, the absence of any one component in the composite catalyst will severely affect the catalytic effect.

[0050] According to Comparative Examples 3-4, replacing sulfuric acid with hydrochloric acid or nitric acid did not produce the catalytic effect of sulfuric acid.

[0051] II. Staining Effect Detection The N-acetylglucosamine sample prepared in Example 1 was used for staining, denoted as Application Example 1.

[0052] Application Example 1 The N-acetylglucosamine sample prepared in Example 1 was used for dyeing. The dyeing method was the one disclosed in the patent application number 202410815387X. The specific dyeing process was as follows: 2g of N-acetylglucosamine powder was dissolved in 1L of pure water, 2g of sodium hydrosulfite was added for reduction, the pH of the dyeing solution was adjusted to 7.5 with sodium hydroxide, and the solution was sealed and left to reduce for 15min. The cotton or linen fabric was then soaked in the solution at a bath ratio (N-acetylglucosamine dyeing solution mass: dyed cotton fabric mass) of 10:1. After dyeing at 25℃ for 10min, the fabric was removed and dried for 5min for oxidation. The fabric was then soaped at a bath ratio of 10:1 and a temperature of 25℃ for 10min. After drying, the fabric was removed and dried. Figure 5 Images show cotton and linen fabrics dyed with N-acetylglucosamine prepared in Example 1. Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the present invention.

Claims

1. A method for preparing N-acetylglucosamine blue, characterized in that, Includes the following steps: N,N'-diacetyl styrax was dispersed in water to obtain a reaction dispersion. A composite catalyst was added to cause the N,N'-diacetyl styrax to undergo a hydrolysis reaction. Then, a terminator was added to terminate the reaction and a solid was precipitated. After solid-liquid separation, the solid was dried to obtain N-acetyl styrax. The composite catalyst includes H2SO4 and aluminum chloride; The terminating agent comprises water at 0-5°C.

2. The method for preparing N-acetylglucosamine blue as described in claim 1, characterized in that, The mass ratio of H2SO4 to aluminum chloride in the composite catalyst is 1:(1.5-2.5).

3. The method for preparing N-acetylglucosamine as described in claim 1 or 2, characterized in that, The mass ratio of the composite catalyst to N,N'-diacetyl blue is (0.01-0.02):

1.

4. The method for preparing N-acetylglucosamine blue as described in claim 3, characterized in that, The mass ratio of aluminum chloride to N,N'-diacetyl blue is (0.007-0.012):

1.

5. The method for preparing N-acetylglucosamine blue as described in claim 1, characterized in that, The hydrolysis reaction is carried out at a temperature of 15-35℃ for 1-2 hours.

6. The method for preparing N-acetylglucosamine as described in claim 5, characterized in that, The hydrolysis reaction was carried out at a temperature of 20-30℃ for 1.5 h.

7. The method for preparing N-acetylglucosamine blue as described in claim 1, characterized in that, The mass ratio of N,N'-diacetyl blue to water in the reactant dispersion is (0.4-0.6):

1.

8. The method for preparing N-acetylglucosamine as described in claim 1 or 7, characterized in that, The mass ratio of the terminator to the reactant dispersion is (2.8-5):

1.

9. The method for preparing N-acetylglucosamine blue as described in claim 1, characterized in that, The drying temperature is 60-90℃.

10. The application of N-acetylglucosamine prepared by the method described in claims 1-7 in fabric dyeing.

Images