A method for improving the light transmission of n-acetylglucosamine

Abstract

This invention discloses a method for improving the transmittance of N-acetylglucosamine, comprising the steps of: (1) acid leaching ferrosilicon slag particles and then reacting them with Cu 2+ After the saturated liquid of the source is mixed evenly and allowed to stand, the solid is taken out and added to sodium borohydride solution to react, and modified ferrosilicon slag particles are obtained. (2) The solid product obtained by drying the leaching solution obtained by the acid leaching treatment is mixed with anhydrous ethanol to form a saturated ethanol solution, and the tetraethyl titanate is diluted with it to form a treatment solution. The modified ferrosilicon slag particles that have absorbed the treatment solution are placed in a steam environment for thermal steam treatment. After completion, the modified ferrosilicon slag particles are calcined to obtain the treatment agent. (3) The treatment agent is added to the N-acetylglucosamine (NAG) solution and then subjected to visible light irradiation treatment to obtain the product. The above process of the present invention can effectively reduce the pigment content in NAG, improve the transmittance and purity of NAG, and thus improve the quality of NAG.

Description

Technical Field

[0001] This invention relates to the field of N-acetylglucosamine technology, and more particularly to a method for improving the transmittance of N-acetylglucosamine. Background Technology

[0002] N-acetylglucosamine (NAG) has the molecular formula C8H12. 15 NO6 has the following molecular structure: .

[0003] N-acetylglucosamine is a fundamental building block of many important polysaccharides in biological cells. It is a crucial prerequisite for the synthesis of bifidus factors and plays many important physiological roles in the body. N-acetylglucosamine is also a basic building block of functional oligoacetylglucosamine, which can increase the number of antibody-forming cells and NK cell activity, thereby enhancing immune function. Furthermore, N-acetylglucosamine is an important component of cartilage and synovial fluid, stimulating chondrocyte growth, promoting chondrocyte metabolism, promoting synovial fluid secretion, and relieving joint pain. Currently, the main artificial preparation methods for N-acetylglucosamine include biological extraction, fermentation, and enzymatic hydrolysis. Enzymatic hydrolysis is costly and rarely used in industrial production. The first two processes are currently the main routes for industrial production of N-acetylglucosamine. However, N-acetylglucosamine prepared by these processes usually contains certain impurities. The pigments in these impurities not only affect the purity of N-acetylglucosamine but also its transmittance, adversely affecting the quality and appearance of the product, thus impacting its marketability. Summary of the Invention

[0004] This invention provides a method for improving the transmittance of N-acetylglucosamine (NAG), which helps to reduce the pigment content in NAG, increase its transmittance and purity, and thus improve the quality of NAG. To achieve the above objective, this invention discloses the following technical solution.

[0005] A method for improving the transmittance of N-acetylglucosamine includes the following steps: (1) Mix the ferrosilicon slag particles with hydrochloric acid for acid leaching treatment, then separate the solid and liquid, collect the leaching liquid for later use, and mix the separated solid with Cu 2+ After the saturated liquid from the source is mixed evenly and allowed to stand, the solid is taken out and added to a sodium borohydride solution for reduction reaction to obtain modified ferrosilicon slag particles.

[0006] (2) After neutralizing the leaching solution with alkali, the product is dried to remove moisture. The resulting solid product is added to anhydrous ethanol and stirred until it no longer dissolves. The undissolved solid product is then removed, and the resulting saturated ethanol solution is used to dilute tetraethyl titanate to form a treatment solution. The modified ferrosilicon slag particles are added to this treatment solution and allowed to stand. The modified ferrosilicon slag particles are then removed, drained, and placed in a steam environment for thermal evaporation. After completion, the modified ferrosilicon slag particles are calcined at a temperature higher than the melting point of copper but lower than the melting point of titanium dioxide. After completion, the resulting product is washed with water and dried to obtain the treatment agent.

[0007] (3) Dissolve N-acetylglucosamine in water, then add the treatment agent and treat with visible light. After the treatment agent is completed, separate the treatment agent, add ethanol to the remaining liquid phase for alcohol precipitation, separate the precipitated crystals, and dry to obtain purified N-acetylglucosamine.

[0008] Further, in step (1), the acid leaching treatment time is 1-2 hours, and the mass fraction of the hydrochloric acid is 20-30%. The particle size of the ferrosilicon slag particles is 1-3 mm. Acid leaching helps to remove soluble impurities from the ferrosilicon slag, while also increasing the pore volume of the ferrosilicon slag and extracting iron from it.

[0009] Further, in step (1), the proportion of solids added to the saturated liquid is 30~45 g / L. Optionally, the Cu... 2+ The source includes at least one of copper chloride, copper sulfate, copper acetate, copper nitrate, etc.

[0010] Further, in step (1), the settling time is 25-40 minutes, so that the Cu 2+ The saturated liquid from the source fully enters the pores of the ferrosilicon slag particles.

[0011] Further, in step (1), the mass fraction of the sodium borohydride solution is 5-10%, and the reduction reaction time is 20-30 min. The Cu is then reduced using the sodium borohydride solution. 2+ It is reduced to elemental copper and loaded onto the ferrosilicon slag particles.

[0012] Further, in step (2), the alkaline solution includes at least one of sodium hydroxide, sodium carbonate, sodium bicarbonate, etc., to remove residual hydrochloric acid from the leaching solution.

[0013] Further, in step (2), the volume ratio of tetraethyl titanate to saturated ethanol is 5:2~3.

[0014] Further, in step (2), the ratio of the modified ferrosilicon slag particles to the treatment liquid is 1g: 20~40ml. Optionally, the settling time is 20~35min, so that the treatment liquid enters the modified ferrosilicon slag particles.

[0015] Furthermore, in step (2), the heat treatment time is 40~50 min, during which the tetraethyl titanate undergoes hydrolysis to form titanium hydroxide gel doped with the iron ions.

[0016] Furthermore, in step (2), the calcination temperature is 1100~1150℃ and the time is 8~12min.

[0017] Further, in step (3), the proportion of the treatment agent added to the aqueous solution of N-acetylglucosamine is 3~5 g / L.

[0018] Furthermore, in step (3), the visible light irradiation treatment time is 1.5 to 2 hours, and the power of the visible light is 60 to 100W.

[0019] Furthermore, in step (3), the ethanol is 3 to 5 times the volume of the liquid phase, the mass fraction of the ethanol is not less than 95%, and the N-acetylglucosamine is insoluble in ethanol, so it can crystallize out to achieve the extraction of the target product.

[0020] Furthermore, in step (3), the drying method includes any one of freeze drying, vacuum heating drying, etc.

[0021] Compared with the prior art, the present invention has at least the following beneficial technical effects: The present invention uses the prepared treatment agent to treat an aqueous solution of N-acetylglucosamine under light irradiation, utilizing photocatalysis to degrade and remove pigments in N-acetylglucosamine, thereby improving not only the purity of N-acetylglucosamine but also its transmittance and overall quality. To this end, the present invention first uses ferrosilicon slag as raw material, subjecting it to acid leaching to extract iron elements. This utilizes the abundant iron content in the ferrosilicon slag to enhance the photocatalytic response of the obtained treatment agent in the visible light range, while simultaneously increasing the surface area of ​​the ferrosilicon slag, which is beneficial for improving the photocatalytic ability of the obtained treatment agent. Furthermore, the present invention adsorbs Cu-containing substances into the ferrosilicon slag after the above treatment. 2+The saturated solution from the source is then subjected to a reduction reaction, thereby pre-forming a copper elemental loading layer on the ferrosilicon slag to form modified ferrosilicon slag particles. Simultaneously, the extract obtained from the acid leaching treatment is neutralized with an alkali solution and then heated to dryness. The resulting solid product is added to anhydrous ethanol, where the ferric chloride dissolves into the ethanol to form a saturated ethanol solution containing iron ions. The sodium chloride formed during neutralization in the solid product is almost insoluble and is thus separated and removed. The present invention uses the aforementioned saturated ethanol solution to dilute tetraethyl titanate and adsorbs it onto the modified ferrosilicon slag particles, thereby loading the modified ferrosilicon slag particles with tetraethyl titanate containing iron ions. Furthermore, the present invention employs a thermal steam treatment method to process the modified ferrosilicon slag particles. This thermal steam treatment not only hydrolyzes the tetraethyl titanate to form an iron-doped titanium hydroxide gel but also helps reduce the dissolution of iron ions from the slag particles. After calcination, the titanium hydroxide gel decomposes to form titanium dioxide particles. Simultaneously, iron ions diffuse into the titanium dioxide lattice at high temperature, forming dopant. Since the titanium dioxide particles are loaded onto a copper layer, when the calcination temperature exceeds the melting point of copper, the copper melts and bonds with the titanium dioxide particles. Upon cooling, the copper solidifies again, thus firmly anchoring the titanium dioxide particles to the ferrosilicon slag, preventing them from detaching during use and extending the lifespan of the treatment agent for repeated use. Furthermore, the copper provided by the copper during calcination can also diffuse into the titanium dioxide lattice, forming dopant. Since iron and copper have multiple energy levels and intermediate valence states, this multi-metallic doping helps improve the photocatalytic response of titanium dioxide in the visible light range. When the treatment agent of the present invention is added to an aqueous solution of N-acetylglucosamine and subjected to phototreatment, the pigments in N-acetylglucosamine are degraded by the photocatalytic action of titanium dioxide, thereby removing the pigments from N-acetylglucosamine, improving the purity and transmittance of N-acetylglucosamine, and improving the quality of N-acetylglucosamine. Attached Figure Description

[0022] The accompanying drawings, which form part of this specification, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Hereinafter, embodiments of the invention will be described in detail with reference to the accompanying drawings, wherein: Figure 1 The following is a diagram showing the effect of N-acetylglucosamine prepared in Example 1. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0024] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments of the present invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The technical solutions of the present invention will now be further described through specific embodiments.

[0025] Example 1 A method for improving the transmittance of N-acetylglucosamine includes the following steps: (1) Mix ferrosilicon slag particles with a particle size of 1-3 mm with 30% hydrochloric acid and stir until homogeneous. Then let stand for 1.5 hours for acid leaching treatment. After completion, filter to separate the ferrosilicon slag particles and collect the leaching solution for later use. Mix the separated ferrosilicon slag particles with saturated copper chloride solution at an addition ratio of 40 g / L and stir until homogeneous. Then let stand for 30 min. After completion, filter to separate the ferrosilicon slag particles and add them to an 8% sodium borohydride solution to react for 20 min. Then filter out the solid product in the reaction system to obtain modified ferrosilicon slag particles.

[0026] (2) Add sodium hydroxide to the leaching solution obtained in step (1) to neutralize and remove residual hydrochloric acid. Then heat the obtained reaction solution to dryness at 90°C. Add the obtained solid product to anhydrous ethanol and stir until it no longer dissolves. Then filter to remove the undissolved solid product to obtain saturated ethanol solution.

[0027] (3) The saturated ethanol solution and tetraethyl titanate are mixed at a volume ratio of 5:2 and stirred evenly to form a treatment solution. The modified ferrosilicon slag particles are mixed with the treatment solution at a ratio of 1g:30ml and stirred evenly. After standing for 30min, the modified ferrosilicon slag particles are filtered out and drained. Then, they are placed on the support net in the reactor (the support net is located above the water in the reactor). The reactor is heated to 100℃ in a water bath and maintained for 45min to perform thermal steam treatment on the modified ferrosilicon slag particles in a steam environment.

[0028] (4) The modified ferrosilicon slag particles obtained by the thermal steam treatment are heated to 1120°C at a rate of 10°C / min and held for 10 min. After completion, the mixture is cooled to room temperature, and the calcined product is washed with water and dried to obtain the treatment agent.

[0029] (5) Dissolve N-acetylglucosamine in water, then add the treatment agent at a ratio of 4 g / L and stir until homogeneous to form the treatment system. Irradiate the treatment system with a 70W xenon lamp for 2 hours. After treatment, filter and separate the treatment agent. Add 5 times its volume of 99% ethanol to the filtered liquid phase, stir until homogeneous, let stand for 35 minutes, then centrifuge to separate the precipitated crystals. Dry the crystals under vacuum at 60°C for 2 hours to obtain purified N-acetylglucosamine, as shown below. Figure 1 As shown.

[0030] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.81% and the transmittance was 99.64%.

[0031] Example 2 A method for improving the transmittance of N-acetylglucosamine includes the following steps: (1) Mix ferrosilicon slag particles with a particle size of 1-3 mm with 20% hydrochloric acid by mass and stir until homogeneous. Then let stand for 2 hours for acid leaching treatment. After completion, filter to separate the ferrosilicon slag particles and collect the leaching solution for later use. Mix the separated ferrosilicon slag particles with saturated copper sulfate solution at an addition ratio of 30 g / L and stir until homogeneous. Then let stand for 25 min. After completion, filter to separate the ferrosilicon slag particles and add them to a 5% sodium borohydride solution by mass and react for 25 min. Then filter out the solid product in the reaction system to obtain modified ferrosilicon slag particles.

[0032] (2) Add sodium carbonate to the leaching solution obtained in step (1) to neutralize and remove residual hydrochloric acid. Then heat the resulting reaction solution to dryness at 95°C. Add the obtained solid product to anhydrous ethanol and stir until it no longer dissolves. Then filter to remove the undissolved solid product to obtain a saturated ethanol solution.

[0033] (3) The saturated ethanol solution and tetraethyl titanate are mixed at a volume ratio of 5:2.5 and stirred evenly to form a treatment solution. The modified ferrosilicon slag particles are mixed with the treatment solution at a ratio of 1g:20ml and stirred evenly. After standing for 35 minutes, the modified ferrosilicon slag particles are filtered out and drained. Then, they are placed on the support net in the reactor (the support net is located above the water in the reactor). The reactor is heated to 100°C in a water bath and kept at 40 minutes to perform thermal steam treatment on the modified ferrosilicon slag particles in a steam environment.

[0034] (4) The modified ferrosilicon slag particles obtained by the thermal steam treatment are heated to 1100℃ at a rate of 10℃ / min and held for 12min. After completion, the mixture is cooled to room temperature, and the calcined product is washed with water and dried to obtain the treatment agent.

[0035] (5) Dissolve N-acetylglucosamine in water, and then add the treatment agent at a ratio of 3 g / L and stir evenly to form the treatment system. Irradiate the treatment system with a 60W xenon lamp for 2 hours. After the treatment is completed, filter and separate the treatment agent. Add 4 times its volume of 95% ethanol to the filtered liquid phase, stir evenly, let stand for 30 min, and then centrifuge to separate the precipitated crystals. Dry the crystals under vacuum at 60℃ for 2 hours to obtain purified N-acetylglucosamine.

[0036] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.75% and the transmittance was 99.47%.

[0037] Example 3 A method for improving the transmittance of N-acetylglucosamine includes the following steps: (1) Mix ferrosilicon slag particles with a particle size of 1-3 mm with 25% hydrochloric acid and stir until homogeneous. Then let stand for 2 hours for acid leaching treatment. After completion, filter to separate the ferrosilicon slag particles and collect the leaching solution for later use. Mix the separated ferrosilicon slag particles with saturated copper acetate solution at an addition ratio of 45 g / L and stir until homogeneous. Then let stand for 35 min. After completion, filter to separate the ferrosilicon slag particles and add them to a 10% sodium borohydride solution to react for 20 min. Then filter out the solid product in the reaction system to obtain modified ferrosilicon slag particles.

[0038] (2) Sodium bicarbonate is added to the leaching solution obtained in step (1) to neutralize and remove residual hydrochloric acid. Then the resulting reaction solution is heated to dryness at 95°C. The obtained solid product is added to anhydrous ethanol and stirred until it no longer dissolves. Then the undissolved solid product is removed by filtration to obtain a saturated ethanol solution.

[0039] (3) The saturated ethanol solution and tetraethyl titanate are mixed at a volume ratio of 5:3 and stirred evenly to form a treatment solution. The modified ferrosilicon slag particles are mixed with the treatment solution at a ratio of 1g:40ml and stirred evenly. After standing for 20 minutes, the modified ferrosilicon slag particles are filtered out and drained. Then, they are placed on the support net in the reactor (the support net is located above the water in the reactor). The reactor is heated to 100°C in a water bath and kept at that temperature for 50 minutes to perform thermal steam treatment on the modified ferrosilicon slag particles in a steam environment.

[0040] (4) The modified ferrosilicon slag particles obtained by the thermal steam treatment are heated to 1150°C at a rate of 10°C / min and held for 8 min. After completion, the mixture is cooled to room temperature, and the calcined product is washed with water and dried to obtain the treatment agent.

[0041] (5) Dissolve N-acetylglucosamine in water, and then add the treatment agent at a ratio of 5 g / L and stir evenly to form the treatment system. Irradiate the treatment system with a 100W xenon lamp for 1.5 hours. After completion, filter and separate the treatment agent. Add 3 times its volume of 95% ethanol to the filtered liquid phase, stir evenly, let stand for 30 min, then centrifuge to separate the precipitated crystals, freeze-dry them to obtain purified N-acetylglucosamine.

[0042] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.58% and the transmittance was 99.4%.

[0043] Example 4 A method for improving the transmittance of N-acetylglucosamine includes the following steps: (1) Mix ferrosilicon slag particles with a particle size of 1-3 mm with 30% hydrochloric acid and stir until homogeneous. Then let stand for 1 hour for acid leaching treatment. After completion, filter to separate the ferrosilicon slag particles and collect the leaching solution for later use. Mix the separated ferrosilicon slag particles with saturated copper nitrate solution at an addition ratio of 35 g / L and stir until homogeneous. Then let stand for 40 min. After completion, filter to separate the ferrosilicon slag particles and add them to a 6% sodium borohydride solution to react for 30 min. Then filter out the solid product in the reaction system to obtain modified ferrosilicon slag particles.

[0044] (2) Add sodium carbonate to the leaching solution obtained in step (1) to neutralize and remove residual hydrochloric acid, then heat the obtained reaction solution to dryness at 90°C, add the obtained solid product to anhydrous ethanol and stir until it no longer dissolves, then filter to remove undissolved solid product, and obtain saturated ethanol solution.

[0045] (3) The saturated ethanol solution and tetraethyl titanate are mixed at a volume ratio of 5:3 and stirred evenly to form a treatment solution. The modified ferrosilicon slag particles are mixed with the treatment solution at a ratio of 1g:25ml and stirred evenly. After standing for 20 minutes, the modified ferrosilicon slag particles are filtered out and drained. Then, they are placed on the support net in the reactor (the support net is located above the water in the reactor). The reactor is heated to 100°C in a water bath and maintained for 45 minutes to perform thermal steam treatment on the modified ferrosilicon slag particles in a steam environment.

[0046] (4) The modified ferrosilicon slag particles obtained by the thermal steam treatment are heated to 1140°C at a rate of 10°C / min and held for 10 min. After completion, the mixture is cooled to room temperature, and the calcined product is washed with water and dried to obtain the treatment agent.

[0047] (5) Dissolve N-acetylglucosamine in water, and then add the treatment agent at a ratio of 4.5 g / L and stir until homogeneous to form the treatment system. Irradiate the treatment system with an 80W xenon lamp for 2 hours. After completion, filter and separate the treatment agent. Add 5 times its volume of 99% ethanol to the filtered liquid phase, stir until homogeneous, let stand for 35 min, then centrifuge to separate the precipitated crystals. After freeze-drying, obtain purified N-acetylglucosamine.

[0048] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.46% and the transmittance was 99.23%.

[0049] Example 5 A method for improving the transmittance of N-acetylglucosamine includes the following steps: The treatment agent in this embodiment is the treatment agent prepared in Example 1 above, which has been reused 5 times. N-acetylglucosamine is dissolved in water, and then the treatment agent is added at a ratio of 4 g / L and stirred until homogeneous to form the treatment system. The treatment system is irradiated with a 70W xenon lamp for 2 hours. After treatment, the treatment agent is filtered out. Five times the volume of 99% ethanol is added to the filtered liquid phase, stirred until homogeneous, and allowed to stand for 35 minutes. The precipitated crystals are then separated by centrifugation and dried under vacuum at 60°C for 2 hours to obtain purified N-acetylglucosamine.

[0050] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.77% and the transmittance was 99.52%.

[0051] Example 6 A method for improving the transmittance of N-acetylglucosamine is the same as in Example 1 above, except that the modified ferrosilicon slag particles in this example are prepared by the following method: ferrosilicon slag particles with a particle size of 1-3 mm are mixed with 30% hydrochloric acid by mass and stirred evenly, then allowed to stand for 1.5 hours for acid leaching treatment. After completion, the solid product is separated by filtration, thus obtaining the modified ferrosilicon slag particles, and the leaching solution obtained by filtration is collected for later use.

[0052] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.14% and the transmittance was 98.83%.

[0053] Example 7 A method for improving the transmittance of N-acetylglucosamine includes the following steps: The treatment agent in this embodiment is the treatment agent prepared in Example 6 above, which has been reused 5 times. N-acetylglucosamine is dissolved in water, and then the treatment agent is added at a ratio of 4 g / L and stirred until homogeneous to form the treatment system. The treatment system is irradiated with a 70W xenon lamp for 2 hours. After irradiation, the treatment agent is filtered out. Five times the volume of 99% ethanol is added to the filtered liquid phase, stirred until homogeneous, and allowed to stand for 35 minutes. The precipitated crystals are then separated by centrifugation and vacuum dried at 60°C for 2 hours to obtain purified N-acetylglucosamine.

[0054] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 98.62% and the transmittance was 98.17%.

[0055] Example 8 A method for improving the transmittance of N-acetylglucosamine, similar to Example 3 above, except that the treatment agent is prepared using the following method: (1) Mix ferrosilicon slag particles with a particle size of 1-3 mm with 25% hydrochloric acid and stir until homogeneous. Then let stand for 2 hours for acid leaching treatment. After completion, filter to separate the ferrosilicon slag particles. Mix the separated ferrosilicon slag particles with saturated copper acetate solution at an addition ratio of 45 g / L and stir until homogeneous. Then let stand for 35 min. After completion, filter to separate the ferrosilicon slag particles and add them to a 10% sodium borohydride solution to react for 20 min. Then filter out the solid product in the reaction system to obtain modified ferrosilicon slag particles.

[0056] (2) Anhydrous ethanol and tetraethyl titanate were mixed at a volume ratio of 5:3 and stirred until homogeneous to form a treatment solution. The modified ferrosilicon slag particles were mixed with the treatment solution at a ratio of 1g:40ml and stirred until homogeneous. The mixture was then allowed to stand for 20 minutes. The modified ferrosilicon slag particles were then filtered out and drained. They were then placed on a support mesh in a reaction vessel (the support mesh was positioned above the water in the reaction vessel). The reaction vessel was heated to 100°C in a water bath and maintained for 50 minutes to perform thermal steam treatment on the modified ferrosilicon slag particles in a steam environment.

[0057] (3) The modified ferrosilicon slag particles obtained by the thermal steam treatment are heated to 1150°C at a rate of 10°C / min and held for 8 min. After completion, the mixture is cooled to room temperature, and the calcined product is washed with water and dried to obtain the treatment agent.

[0058] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.21% and the transmittance was 98.96%.

[0059] Example 9 A method for improving the transmittance of N-acetylglucosamine, similar to Example 4 above, differs in that the treatment agent is prepared using the following method: (1) Mix ferrosilicon slag particles with a particle size of 1-3 mm with 30% hydrochloric acid by mass and stir until uniform, then let stand for 1 hour for acid leaching treatment. After completion, filter to separate the solid product, and obtain modified ferrosilicon slag particles.

[0060] (2) Anhydrous ethanol and tetraethyl titanate were mixed at a volume ratio of 5:3 and stirred until homogeneous to form a treatment solution. The modified ferrosilicon slag particles were mixed with the treatment solution at a ratio of 1g:25ml and stirred until homogeneous. The mixture was then allowed to stand for 20 minutes. The modified ferrosilicon slag particles were then filtered out and drained. They were then placed on a support mesh in a reaction vessel (the support mesh was positioned above the water in the reaction vessel). The reaction vessel was heated to 100°C in a water bath and maintained for 45 minutes to perform thermal steam treatment on the modified ferrosilicon slag particles in a steam environment.

[0061] (3) The modified ferrosilicon slag particles obtained by the thermal steam treatment are heated to 1140°C at a rate of 10°C / min and held for 10 min. After completion, the mixture is cooled to room temperature, and the calcined product is washed with water and dried to obtain the treatment agent.

[0062] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 98.54% and the transmittance was 98.02%.

[0063] Example 10 A method for improving the transmittance of N-acetylglucosamine, similar to Example 2 above, except that the treatment agent is prepared using the following method: The saturated ethanol solution and tetraethyl titanate were mixed at a volume ratio of 5:2.5 and stirred until homogeneous to form a treatment solution. The modified ferrosilicon slag particles were mixed with this treatment solution at a ratio of 1g:20ml and stirred until homogeneous. The mixture was then allowed to stand for 35 minutes. The modified ferrosilicon slag particles were then filtered out and drained. They were then placed in a reaction vessel filled with clean water and heated in a water bath to 100°C for 40 minutes to carry out the hydrolysis reaction of the tetraethyl titanate. After completion, the solid product in the reaction vessel was filtered out. The solid product was heated to 1100°C at a heating rate of 10°C / min and held for 12 minutes. After completion, the mixture was cooled to room temperature, and the resulting calcined product was washed with clean water and dried to obtain the treatment agent.

[0064] The purity and transmittance of the N-acetylglucosamine obtained in this embodiment were tested by spectrophotometry. The results showed that the purity was 99.33% and the transmittance was 99.14%.

[0065] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for improving the transmittance of N-acetylglucosamine, characterized in that, Includes the following steps: (1) Mix the ferrosilicon slag particles with hydrochloric acid for acid leaching, then separate the solid and liquid, collect the leaching liquid for later use, and mix the separated solid with Cu 2+ After the saturated liquid of the source is mixed evenly, it is allowed to stand. After completion, the solid is taken out and added to sodium borohydride solution for reduction reaction to obtain modified ferrosilicon slag particles; the proportion of solid added to the saturated liquid is 30~45g / L. (2) After adding alkali solution to the leaching solution to neutralize it, dry it to remove water, add the obtained solid product to anhydrous ethanol and stir until it no longer dissolves, then remove the undissolved solid product, dilute tetraethyl titanate with the obtained saturated ethanol solution to form a treatment solution; add the modified ferrosilicon slag particles to the treatment solution at a ratio of 1g:20~40ml and let it stand, then take out the modified ferrosilicon slag particles and drain them, and then place them in a steam environment for hot steam treatment for 40~50min; after completion, the obtained modified ferrosilicon slag particles are calcined, and the calcination temperature is higher than the melting point of copper and lower than the melting point of titanium dioxide; after completion, the obtained product is washed with water and dried to obtain the treatment agent; the calcination temperature is 1100~1150℃ and the time is 8~12min; (3) Dissolve N-acetylglucosamine in water, then add the treatment agent and treat with visible light. After the treatment agent is completed, separate the treatment agent, add ethanol to the remaining liquid phase for alcohol precipitation, separate the precipitated crystals, and dry to obtain purified N-acetylglucosamine.

2. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (1), the acid leaching treatment time is 1 to 2 hours, and the mass fraction of the hydrochloric acid is 20 to 30%.

3. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (1), the particle size of the ferrosilicon slag particles is 1~3mm.

4. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (1), the Cu 2+ The source includes at least one of copper chloride, copper sulfate, copper acetate, and copper nitrate.

5. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (1), the settling time is 25~40 minutes.

6. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (1), the mass fraction of the sodium borohydride solution is 5-10%, and the reduction reaction time is 20-30 min.

7. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (2), the alkaline solution includes at least one of sodium hydroxide, sodium carbonate, and sodium bicarbonate.

8. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (2), the volume ratio of tetraethyl titanate to saturated ethanol is 5:2~3.

9. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, The settling time is 20-35 minutes.

10. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (3), the proportion of the treatment agent added to the aqueous solution of N-acetylglucosamine is 3~5 g / L.

11. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (3), the visible light irradiation treatment time is 1.5 to 2 hours, and the power of the visible light is 60 to 100W.

12. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (3), the ethanol is 3 to 5 times the volume of the liquid phase, and the mass fraction of the ethanol is not less than 95%.

13. The method for improving the transmittance of N-acetylglucosamine according to claim 1, characterized in that, In step (3), the drying method includes either freeze drying or vacuum heating drying.

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