A process for purifying and refining crude glucosamine hydrochloride

Abstract

The application discloses a kind of glucosamine hydrochloride crude product purification refining process, comprising the following steps: (1) glucosamine hydrochloride crude product is dissolved in water, then add the composite precipitant consisting of sodium chloride and sodium hydroxide, after standing, solid-liquid separation, collected separated liquid phase.(2) after the liquid phase is concentrated, add sodium percarbonate and mix evenly and stand still.After completion, pass in carbon dioxide to convert sodium hydroxide in concentrated solution into sodium carbonate, then continue to add calcium nitrate under stirring condition to make carbonate ion in system complete precipitation, i.e., the liquid to be extracted is obtained.(3) after the liquid to be extracted is cooled, add ethanol for alcohol precipitation, after completion, carry out solid-liquid separation, and the obtained solid product and separated liquid are collected respectively.The solid product is washed with ethanol and dried, and glucosamine hydrochloride finished product is obtained.The above process not only can improve the purity of glucosamine hydrochloride, but also can improve the yield of glucosamine hydrochloride in alcohol precipitation process, thereby reducing waste.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of glucosamine hydrochloride, and particularly relates to a purification and refining process of crude glucosamine hydrochloride. BACKGROUND

[0002] The joint can be simply understood as the part of two bones connected, which includes five parts of bones, joint capsules, synovial membranes, synovial fluid and cartilages, wherein the cartilage composed of calcium carbonate, chondroitin sulfate sodium, glucosamine and collagen and the like is the key to the onset of arthritis: when the glucosamine is sufficient, the cartilage is healthy and elastic, and when the glucosamine is absent, the cartilage is in a worn state, thereby causing problems of joint pain, hyperplasia, deformation and the like. Especially for the elderly, the body function is decreased, and the metabolism is weakened, so that the glucosamine synthesized in the body cannot meet the needs of the body, and thus the arthritis is more likely to occur. For this group of people, supplementing the glucosamine from the outside world is one of the effective ways to relieve arthritis.

[0003] At present, the glucosamine on the market mainly includes two categories of glucosamine hydrochloride and glucosamine sulfate. Compared with the latter, the glucosamine hydrochloride has better stability, and the glucosamine sulfate is easy to absorb moisture and deliquesce. Therefore, part of sodium chloride is usually added in the glucosamine sulfate. In addition, the glucosamine hydrochloride also has advantages of high purity and lower cost. One of the common preparation methods of the glucosamine hydrochloride is to take the chitin rich in shrimp and crab shells as raw materials, then to perform hydrolysis by using concentrated hydrochloric acid, and to obtain the crude glucosamine hydrochloride by performing alcohol precipitation on the obtained hydrolyzate, wherein the crude glucosamine hydrochloride contains many impurities such as proteins and pigments, which affects the purity of the glucosamine hydrochloride. Therefore, the crude glucosamine hydrochloride is further refined and purified to prepare high-quality glucosamine hydrochloride. SUMMARY

[0004] The present application provides a purification and refining process of crude glucosamine hydrochloride, which can not only improve the purity of the glucosamine hydrochloride, but also improve the yield of the glucosamine hydrochloride in the alcohol precipitation process, thereby reducing waste. In order to achieve the above purpose, the present application discloses the technical scheme as shown below.

[0005] A purification and refining process of crude glucosamine hydrochloride, comprising the following steps:

[0006] (1) Dissolve the crude glucosamine hydrochloride in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide, mix uniformly and then stand still. After completion, perform solid-liquid separation, and collect the separated liquid phase.

[0007] (2) After concentrating the liquid phase, a concentrated solution is obtained. Sodium percarbonate is then added to the concentrated solution, mixed, and allowed to stand. After completion, carbon dioxide is introduced to convert the sodium hydroxide in the concentrated solution into sodium carbonate. Then, calcium nitrate is added under stirring to precipitate the carbonate ions in the system, thus obtaining the extract to be obtained.

[0008] (3) After cooling the extract, add ethanol for alcohol precipitation. After precipitation, perform solid-liquid separation and collect the obtained solid product and separated liquid. Wash the solid product with ethanol and dry it to obtain glucosamine hydrochloride product.

[0009] Furthermore, in step (1), after adding the composite precipitant, the mass fraction of sodium chloride in the reaction system is 3~5.5%, and the mass fraction of sodium hydroxide is 0.5~0.8%.

[0010] Further, in step (1), the settling time is 20-35 minutes, so that the protein in the reaction system is precipitated and washed out under the action of the composite precipitant.

[0011] Further, in step (2), the liquid phase is heated and concentrated to 40-60% of its initial volume to obtain the concentrated liquid.

[0012] Further, in step (2), the sodium percarbonate reacts with the OH in the concentrated solution. - The molar ratio is 3~3.15:1, so as to utilize the hydrogen peroxide released by the sodium percarbonate to concentrate the OH in the solution. - The catalyst forms active oxygen [O] with oxidizing properties for decolorization.

[0013] Furthermore, in step (2), the settling time is 10-20 minutes to utilize the active oxygen [O] for decolorization.

[0014] Further, in step (2), the molar ratio of calcium nitrate to sodium carbonate in the system is 1:1, in order to remove the sodium carbonate.

[0015] Further, in step (3), the extract is cooled to between 2 and 5°C. Optionally, the volume ratio of the extract to ethanol is 1:3 to 4.5, and the alcohol precipitation time is 30 to 40 minutes, so that the glucosamine hydrochloride in the extract gradually crystallizes out.

[0016] Further, in step (3), the solid product is washed with ethanol 2-3 times and then vacuum dried or freeze-dried to obtain the glucosamine hydrochloride product.

[0017] Furthermore, it also includes a step of extracting the separated liquid from step (3), comprising the following steps:

[0018] (i) heating hydrotalcite MgAl-NO3-LDHs in a protective atmosphere to a temperature at which water molecules and nitrate ions are decomposed and removed, then placing the obtained heat-treated product in a sodium bicarbonate solution, mixing and standing, and then separating the solid product, to obtain a modified metastable hydrotalcite.

[0019] (ii) adding the modified metastable hydrotalcite to the separation liquid and performing ultrasonic treatment. After completion, solid-liquid separation is performed, hydrochloric acid is added to the obtained liquid phase to eliminate bicarbonate ions therein, and then the obtained reaction liquid is subjected to freeze-drying treatment, after which the obtained solid product is washed with ethanol and dried, to obtain a glucosamine hydrochloride product.

[0020] Further, in step (i), the heating temperature is 450-490°C, and the time is 30-50 min. Optionally, the protective atmosphere comprises any one of nitrogen, argon, etc., so that the heating is performed in an oxygen-free condition.

[0021] Further, in step (i), the solid-liquid ratio of the heat-treated product to the sodium bicarbonate solution is 1 g: 20-40 ml. Optionally, the mass fraction of the sodium bicarbonate solution is 20-35%, and the standing time is 45-60 min, so that bicarbonate ions and water molecules in the sodium bicarbonate solution enter the heat-treated hydrotalcite MgAl-NO3-LDHs to reconstruct the modified metastable hydrotalcite.

[0022] Further, in step (ii), the solid-liquid ratio of the modified metastable hydrotalcite to the separation liquid is 1 g: 10-15 ml.

[0023] Further, in step (ii), the ultrasonic treatment time is 25-40 min, and the ultrasonic power is 300-450 W.

[0024] Further, in step (ii), the molar ratio of hydrochloric acid to bicarbonate ions in the liquid phase is 1:1, so as to eliminate the bicarbonate ions in the liquid phase.

[0025] Further, in step (ii), the solid product is washed with ethanol for 2-3 times and then vacuum dried or freeze-dried, to obtain the glucosamine hydrochloride product.

[0026] Compared with the prior art, the present application has at least the following beneficial technical effects: first, the present application uses a composite precipitant composed of sodium chloride and sodium hydroxide to treat the reconstituted glucosamine hydrochloride crude product solution, and under the action of the composite precipitant, the protein is coagulated and precipitated, and after solid-liquid separation, the purification and refining of the glucosamine hydrochloride crude product is realized, and an alkaline liquid phase containing sodium chloride is obtained. Further, the present application uses the alkaline environment as a catalyst, and after adding sodium percarbonate in the liquid phase, it is first decomposed into sodium carbonate and hydrogen peroxide molecules (2Na2CO3·3H2O2→ 2Na2CO3+3H2O2), the hydrogen peroxide molecules are further converted into hydroxyl ions (H2O2+OH - →H2O+OOH - ) under the action of hydroxyl ions in the liquid phase, and the hydroxyl ions further release active oxygen [O] (OOH - → OH - ), and this active oxygen [O] has strong oxidation effect, which can oxidize and decompose the pigment in the liquid phase into carbon dioxide and water, realizing decolorization and complete removal of pigment molecules. Not only the pigment is discolored, but it still exists in the form of impurities, so that more complete purification of the glucosamine hydrochloride crude product cannot be realized. Further, the present application uses the sodium carbonate provided by the sodium percarbonate to add calcium nitrate, and the two react to form sodium nitrate and calcium carbonate particles. When the alcohol is precipitated after cooling, the calcium carbonate particles become heterogeneous nucleating agents to promote the nucleation and crystallization of glucosamine hydrochloride, and thus the extraction rate of glucosamine hydrochloride dissolved in the to-be-extracted liquid is improved, and waste is reduced. At the same time, since a large amount of ethanol is added in the to-be-extracted liquid during alcohol precipitation, the sodium nitrate can continue to remain dissolved in the liquid phase, so that the purity of the crystallized and precipitated glucosamine hydrochloride is higher. The calcium carbonate can provide calcium ions and glucosamine for the human body together with glucosamine hydrochloride, and both of them are important components of human joints.

[0027] In addition, the present application further separates and purifies the residual glucosamine hydrochloride in the separation liquid obtained in step (3), so as to reduce the waste of glucosamine hydrochloride. The separation liquid contains sodium nitrate in addition to glucosamine hydrochloride. To this end, the present application prepares modified metastable hydrotalcite to replace nitrate ions, so as to convert the sodium nitrate into sodium bicarbonate, which is converted into sodium chloride after being treated with hydrochloric acid, and the sodium chloride is a component of glucosamine hydrochloride. The above process not only removes the impurity sodium nitrate, but also converts it into a component of glucosamine hydrochloride, which can effectively improve the stability of glucosamine and prevent it from deliquescing. In order to realize the replacement of the nitrate ions, the present application first uses nitrate-type hydrotalcite MgAl-NO3-LDHs as raw material, and reversibly decomposes and removes the water molecules and nitrate ions in the interlayer of the hydrotalcite by heating at high temperature. The obtained product is further treated with sodium bicarbonate solution, and the water molecules and bicarbonate ions re-enter the interlayer of the hydrotalcite to construct the structure of the hydrotalcite. However, since the hydrotalcite is of nitrate type, the bicarbonate ions embedded in the interlayer are not stable when they are reconstructed with bicarbonate ions, so that the obtained hydrotalcite is in a metastable state, and the MgAl-NO3-LDHs hydrotalcite is modified into metastable hydrotalcite. When the metastable hydrotalcite encounters nitrate, it will replace the nitrate ions to make the hydrotalcite change to a more stable state, i.e. the removal of the nitrate ions in the separation liquid is realized. The bicarbonate ions replaced into the separation liquid form sodium bicarbonate, which is conveniently converted into sodium chloride, a component of glucosamine hydrochloride, by hydrochloric acid, i.e. the removal of the nitrate ions is realized, and the introduction of new impurities is avoided. After replacement, the metastable hydrotalcite changes to MgAl-NO3-LDHs hydrotalcite again, so as to realize regeneration and repeated use. BRIEF DESCRIPTION OF DRAWINGS

[0028] The accompanying drawings, which form a part of the present application, are intended to provide further understanding of the present application and are incorporated herein for a purpose of explanations of the present application. The following detailed description of the illustrative embodiments of the present application is made in connection with the accompanying drawings.

[0029] Figure 1 A real effect picture of the finished glucosamine hydrochloride product prepared for the following Example 1. DETAILED DESCRIPTION

[0030] It should be noted that the following detailed description is exemplary in nature and is intended to provide further description of the present application. Unless otherwise defined, 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 application belongs.

[0031] 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.

[0032] Example 1

[0033] A purification process for crude glucosamine hydrochloride includes the following steps:

[0034] (1) Dissolve crude glucosamine hydrochloride in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide and stir until homogeneous. The mass fraction of sodium chloride in the resulting reaction system is 4%, and the mass fraction of sodium hydroxide is 0.8%. Then let stand for 30 minutes, centrifuge to remove the solid product, collect the liquid phase, and set aside for later use.

[0035] (2) The liquid phase is concentrated to 50% of its initial volume by heating in a water bath at 80°C to obtain a concentrated solution. The concentration is determined by reacting sodium percarbonate with the OH- in the concentrated solution. - The molar ratio of sodium hydroxide to sodium carbonate is 3.1:1. Sodium percarbonate is added to the concentrated solution and stirred until homogeneous. The solution is then allowed to stand for 15 minutes for decolorization. After decolorization, carbon dioxide is passed into the resulting liquid phase to convert sodium hydroxide into sodium carbonate. Then, calcium nitrate is added under stirring conditions, with a molar ratio of calcium nitrate to sodium carbonate of 1:1, to precipitate carbonate ions, thus obtaining the extract.

[0036] (3) Cool the extract to 5°C, then add 4 times the volume of 95% ethanol and let it stand for 35 minutes for alcohol precipitation. After precipitation, centrifuge the resulting reaction system and collect the solid product and the separated liquid. Wash the solid product three times with ethanol and then vacuum dry it at 60°C for 10 minutes to obtain glucosamine hydrochloride product (e.g., Figure 1 (As shown).

[0037] The purity (i.e., the proportion of glucosamine hydrochloride in the finished product) and the extraction rate of glucosamine hydrochloride in this embodiment were tested. The content of glucosamine hydrochloride in the finished product was determined using spectrophotometry; the extraction rate was calculated as: finished glucosamine hydrochloride / crude glucosamine hydrochloride. The test results are shown in the table below.

[0038]

[0039] Example 2

[0040] A purification and refining process of a glucosamine hydrochloride crude product, comprising the following steps:

[0041] (1) Dissolve the glucosamine hydrochloride crude product in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide and stir uniformly, so that the mass fraction of sodium chloride in the obtained reaction system is 5.5% and the mass fraction of sodium hydroxide is 0.5%. Then stand for 20 min, remove the solid product by centrifugation after completion, and collect the liquid phase for standby.

[0042] (2) Heat the liquid phase to 75°C in a water bath and concentrate to 60% of the initial volume to obtain a concentrated liquid. Add sodium percarbonate to the concentrated liquid in a molar ratio of 3:1 of sodium percarbonate to OH - in the concentrated liquid and stir uniformly, then stand for 10 min for decolorization. After completion, pass carbon dioxide into the obtained liquid phase to convert sodium hydroxide therein into sodium carbonate, then continue to add calcium nitrate under stirring, in a molar ratio of 1:1 of calcium nitrate to sodium carbonate in the system, so that the carbonate ions in the system are precipitated, and the liquid to be extracted is obtained.

[0043] (3) Cool the liquid to be extracted to 2°C, then add 3 times the volume of the liquid to be extracted of ethanol with a mass fraction of 95%, then stand for 30 min for alcohol precipitation. After completion, centrifuge the obtained reaction system to collect the solid product and the separation liquid, respectively. Wash the solid product with ethanol for 3 times, then dry at 60°C under vacuum for 10 min, and the glucosamine hydrochloride finished product is obtained.

[0044] The purity of the glucosamine hydrochloride finished product of the present example and the extraction rate of glucosamine hydrochloride are tested by the same method as in Example 1 above, and the test results are shown in the following table.

[0045]

[0046] Example 3

[0047] A purification and refining process of a glucosamine hydrochloride crude product, comprising the following steps:

[0048] (1) Dissolve the glucosamine hydrochloride crude product in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide and stir uniformly, so that the mass fraction of sodium chloride in the obtained reaction system is 3.5% and the mass fraction of sodium hydroxide is 0.6%. Then stand for 35 min, remove the solid product by centrifugation after completion, and collect the liquid phase for standby.

[0049] (2) Heat the liquid phase to 80°C in a water bath and concentrate to 45% of the initial volume to obtain a concentrated liquid. Add sodium percarbonate to the concentrated liquid in a molar ratio of 3:1 of sodium percarbonate to OH- The molar ratio of sodium carbonate to calcium nitrate is 3.15:1. Sodium carbonate is added to the concentrated solution and stirred until uniform, then left to stand for 20 min for decolorization. After completion, carbon dioxide is passed through the obtained liquid phase to convert sodium hydroxide into sodium carbonate, then calcium nitrate is continuously added under stirring, the molar ratio of calcium nitrate to sodium carbonate in the system is 1:1, so that carbonate ions in the system are precipitated, and the liquor to be extracted is obtained.

[0050] (3) The liquor to be extracted is cooled to 3°C, then 3.5 times the volume of the liquor to be extracted of 95% ethanol is added, then left to stand for 40 min for alcohol precipitation. After completion, the obtained reaction system is subjected to centrifugal treatment, and the obtained solid product and separated liquid are collected. The solid product is washed with ethanol twice and then subjected to freeze-drying treatment, and the glucosamine hydrochloride finished product is obtained.

[0051] (4) The hydrotalcite (MgAl-NO3-LDHs) is heated in a nitrogen atmosphere at 490°C for 30 min, and after completion, the obtained heat-treated product is cooled to room temperature in the nitrogen atmosphere. Then the obtained heat-treated product is placed in a 35% sodium bicarbonate solution according to a solid-liquid ratio of 1g:20ml, stirred until uniform, then left to stand for 45 min, and then the solid product is separated by centrifugation, and the modified metastable hydrotalcite is obtained.

[0052] (5) The modified metastable hydrotalcite is added to the separated liquid of step (3) according to a solid-liquid ratio of 1g:15ml for ultrasonic treatment (time is 40 min, ultrasonic power is 300W). After completion, centrifugal treatment is performed, hydrochloric acid is added to the obtained liquid phase, and the molar ratio of hydrochloric acid to bicarbonate in the liquid phase is 1:1. After 5 min of reaction, the obtained reaction liquid is subjected to freeze-drying treatment, and after completion, the obtained solid product is washed with ethanol three times and then vacuum dried at 60°C for 10 min, and the glucosamine hydrochloride finished product is obtained. The glucosamine hydrochloride finished product obtained in step (3) is combined with the glucosamine hydrochloride finished product obtained in this embodiment, and the glucosamine hydrochloride finished product is obtained.

[0053] The purity of the glucosamine hydrochloride finished product and the extraction rate of glucosamine hydrochloride in this embodiment are tested by the same method as in the above embodiment 1, and the test results are shown in the following table.

[0054]

[0055] Example 4

[0056] A purification and refining process for a crude glucosamine hydrochloride product, comprising the following steps:

[0057] (1) Dissolve the crude glucosamine hydrochloride in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide and stir until uniform, so that the mass fraction of sodium chloride in the reaction system is 3% and the mass fraction of sodium hydroxide is 0.5%. Then let stand for 25 min, and after completion, remove the solid product by centrifugation, and collect the liquid phase for later use.

[0058] (2) Concentrate the liquid phase to 40% of the original volume by heating in a water bath at 80°C. Add sodium percarbonate to the concentrated liquid in a molar ratio of 3.1:1 of sodium percarbonate to OH - in the concentrated liquid, and stir until uniform. Then let stand for 15 min for decolorization. After completion, pass carbon dioxide into the obtained liquid phase to convert the sodium hydroxide therein to sodium carbonate, and then continue to add calcium nitrate under stirring, in a molar ratio of 1:1 of calcium nitrate to sodium carbonate in the system, so that the carbonate ions in the system are precipitated, and the resulting liquid is the liquid to be extracted.

[0059] (3) Cool the liquid to be extracted to 4°C, then add ethanol with a mass fraction of 95% in an amount of 4.5 times the volume of the liquid to be extracted, and then let stand for 40 min for alcohol precipitation. After completion, centrifuge the resulting reaction system, and collect the obtained solid product and the separated liquid, respectively. Wash the solid product with ethanol 3 times, and then dry at 60°C under vacuum for 15 min, to obtain the finished product of glucosamine hydrochloride.

[0060] (4) Heat hydrotalcite (MgAl-NO3-LDHs) in a nitrogen atmosphere to 450°C for 50 min, and after completion, cool to room temperature in the nitrogen atmosphere. Then place the obtained heat-treated product in a 20% sodium bicarbonate solution in a solid-liquid ratio of 1 g:40 ml, stir until uniform, and then let stand for 60 min, and then separate the solid product by centrifugation, to obtain the modified metastable hydrotalcite.

[0061] (5) Add the modified metastable hydrotalcite to the separated liquid of step (3) in a solid-liquid ratio of 1 g:10 ml for ultrasonic treatment (time 25 min, ultrasonic power 450 W). After completion, centrifuge, and then add hydrochloric acid to the obtained liquid phase in a molar ratio of 1:1 of hydrochloric acid to bicarbonate, and let stand for 5 min. Then freeze-dry the obtained reaction liquid, and after completion, wash the obtained solid product with ethanol 2 times, and then dry at 60°C under vacuum for 10 min, to obtain the finished product of glucosamine hydrochloride. Combine the finished product of glucosamine hydrochloride obtained in step (3) above with the finished product of glucosamine hydrochloride obtained in this step, to obtain the product.

[0062] The purity of the finished product of glucosamine hydrochloride obtained in this example and the extraction rate of glucosamine hydrochloride were tested by the same method as in Example 1 above, and the test results are shown in the following table.

[0063]

[0064] Example 5

[0065] A purification and refining process of a glucosamine hydrochloride crude product, comprising the following steps:

[0066] (1) Dissolve the glucosamine hydrochloride crude product in water, then add sodium chloride and stir until uniform, so that the mass fraction of sodium chloride in the reaction system is 4%. Then stand for 30 min, and after completion, remove the solid product by centrifugation, and collect the liquid phase for standby.

[0067] (2) Heat the liquid phase to 80°C in a water bath and concentrate to 50% of the initial volume to obtain a concentrated solution. Add sodium percarbonate to the concentrated solution and stir until uniform, wherein the mass fraction of sodium percarbonate is 1.8%, then stand for 15 min for decolorization. After completion, continue to add calcium nitrate under stirring, and the molar ratio of calcium nitrate to sodium carbonate in the system is 1:1, so that the carbonate ions in the system are precipitated, and the eluate is obtained.

[0068] (3) Cool the eluate to 5°C, then add 4 times the volume of the eluate of 95% ethanol, then stand for 35 min for alcohol precipitation. After completion, centrifuge the obtained reaction system to collect the solid product and the separation liquid. Wash the solid product with ethanol 3 times, then vacuum dry at 60°C for 10 min, and the glucosamine hydrochloride finished product is obtained.

[0069] The purity of the glucosamine hydrochloride finished product of the present example and the extraction rate of glucosamine hydrochloride are tested by the same method as in Example 1 above, and the test results are shown in the following table.

[0070]

[0071] Example 6

[0072] A purification and refining process of a glucosamine hydrochloride crude product, comprising the following steps:

[0073] (1) Dissolve the glucosamine hydrochloride crude product in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide and stir until uniform, so that the mass fraction of sodium chloride in the reaction system is 5.5% and the mass fraction of sodium hydroxide is 0.5%. Then stand for 20 min, and after completion, remove the solid product by centrifugation, and collect the liquid phase for standby.

[0074] (2) Heat the liquid phase to 75°C in a water bath and concentrate to 60% of the initial volume to obtain a concentrated solution. According to the molar ratio of sodium percarbonate to OH -The molar ratio of the concentrated solution is 3:1. Sodium carbonate is added to the concentrated solution and stirred uniformly, then left to stand for 10 min for decolorization. After completion, carbon dioxide is passed through the obtained liquid phase to convert sodium hydroxide into sodium carbonate. After completion, the obtained solution is obtained.

[0075] (3) The obtained solution is cooled to 2°C, then 95% ethanol is added in an amount of 3 times the volume of the solution, then left to stand for 30 min for alcohol precipitation. After completion, the obtained reaction system is subjected to centrifugal treatment, and the obtained solid product and separated solution are collected. The solid product is washed with ethanol for 3 times, then vacuum dried at 60°C for 10 min to obtain the glucosamine hydrochloride product.

[0076] The purity of the glucosamine hydrochloride product and the extraction rate of glucosamine hydrochloride are tested by the same method as in Example 1, and the test results are shown in the following table.

[0077]

[0078] Example 7

[0079] A purification and refining process of a crude glucosamine hydrochloride product, steps (1)-(3) are the same as in Example 3, and the difference lies in steps (4) and (5) which are as follows: hydrotalcite (MgAl-NO3-LDHs) is added to the separated solution in step (3) according to a solid-liquid ratio of 1g:15ml for ultrasonic treatment (time is 40 min, ultrasonic power is 300W). After completion, centrifugal treatment is performed, hydrochloric acid is added to the obtained liquid phase, and the molar ratio of the hydrochloric acid to bicarbonate in the liquid phase is 1:1. After 5 min of reaction, the obtained reaction solution is subjected to freeze-drying treatment. After completion, the obtained solid product is washed with ethanol for 3 times, then vacuum dried at 60°C for 10 min to obtain the glucosamine hydrochloride product. The product is combined with the glucosamine hydrochloride product obtained in step (3) in the above embodiment to obtain the product.

[0080] The purity of the glucosamine hydrochloride product and the extraction rate of glucosamine hydrochloride are tested by the same method as in Example 1, and the test results are shown in the following table.

[0081]

[0082] Example 8

[0083] A purification and refining process of a crude glucosamine hydrochloride product, steps (1)-(3) are the same as in Example 3, and the difference lies in:

[0084] (4) The hydrotalcite (MgAl-NO3-LDHs) is heated in a nitrogen atmosphere at 490°C for 30 min, and after completion, cooled to room temperature in the nitrogen atmosphere to obtain the modified hydrotalcite.

[0085] (5) The modified hydrotalcite is added to the separated solution of step (3) in a solid-liquid ratio of 1 g: 15 ml for ultrasonic treatment (time 40 min, ultrasonic power 300 W). After completion, centrifugal treatment is performed, hydrochloric acid is added to the obtained liquid phase, and the molar ratio of the hydrochloric acid to bicarbonate in the liquid phase is 1:1. After 5 min of reaction, the obtained reaction liquid is subjected to freeze-drying treatment, and after completion, the obtained solid product is washed with ethanol for 3 times and then vacuum dried at 60°C for 10 min to obtain the glucosamine hydrochloride product. The glucosamine hydrochloride product obtained in step (3) of the above embodiment is combined to obtain the glucosamine hydrochloride product.

[0086] The purity of the glucosamine hydrochloride product of the present embodiment and the extraction rate of glucosamine hydrochloride are tested by the same method as in the above embodiment 1, and the test results are shown in the following table.

[0087]

[0088] Example 9

[0089] A purification and refining process of a crude glucosamine hydrochloride product, steps (1)-(3) are the same as in the above embodiment 4, with the difference being that:

[0090] (4) The hydrotalcite (MgAl-NO3-LDHs) is heated in a nitrogen atmosphere at 450°C for 50 min, and after completion, cooled to room temperature in the nitrogen atmosphere. Then, the obtained heat-treated product is placed in a 20% sodium bicarbonate solution in a solid-liquid ratio of 1 g: 40 ml, stirred uniformly, and then left to stand for 60 min. Then, the solid product is separated by centrifugation to obtain the modified metastable hydrotalcite.

[0091] (5) The modified metastable hydrotalcite is added to the separated solution of step (3) in a solid-liquid ratio of 1 g: 10 ml for ultrasonic treatment (time 25 min, ultrasonic power 450 W). After completion, centrifugal treatment is performed, and the obtained liquid phase is subjected to freeze-drying treatment. After completion, the obtained solid product is washed with ethanol for 2 times and then vacuum dried at 60°C for 10 min to obtain the glucosamine hydrochloride product. The glucosamine hydrochloride product obtained in step (3) of the above embodiment is combined to obtain the glucosamine hydrochloride product.

[0092] The purity of the glucosamine hydrochloride product of the present embodiment and the extraction rate of glucosamine hydrochloride are tested by the same method as in the above embodiment 1, and the test results are shown in the following table.

[0093]

[0094] The above description is merely that of the preferred embodiments of the present application, and is not intended to limit the present application. The present application can be variously changed and modified by those skilled in the art. Any modification, equivalent replacement, and improvement, etc. made within the spirit and principle of the present application shall fall within the scope of the present application.

Claims

1. A purification and refining process for crude glucosamine hydrochloride, characterized in that, Including the following steps: (1) Dissolve the crude glucosamine hydrochloride in water, then add a composite precipitant composed of sodium chloride and sodium hydroxide, mix well and let stand; after completion, perform solid-liquid separation and collect the separated liquid phase; (2) After the liquid phase is concentrated, sodium percarbonate is added to it, mixed and allowed to stand; after completion, carbon dioxide is introduced to convert sodium hydroxide in the concentrated solution into sodium carbonate, and then calcium nitrate is added under stirring to precipitate carbonate ions in the system, thus obtaining the extract to be extracted. (3) After cooling the liquid to be extracted, add ethanol for alcohol precipitation. After the precipitation is completed, perform solid-liquid separation and collect the obtained solid product and the separated liquid respectively. Wash the solid product with ethanol and dry it to obtain glucosamine hydrochloride product. It also includes a step of extracting the separated liquid from step (3), comprising the following steps: (i) The hydrotalcite MgAl-NO3-LDHs is heated in a protective atmosphere until the water molecules and nitrate ions are decomposed. The heat-treated product is then placed in a sodium bicarbonate solution, mixed, and allowed to stand. The solid product is then separated to obtain the modified metastable hydrotalcite. (ii) The modified metastable hydrotalcite is added to the separation liquid and subjected to ultrasonic treatment; After completion, solid-liquid separation is performed. Hydrochloric acid is added to the obtained liquid phase to eliminate bicarbonate ions. Then, the obtained reaction solution is freeze-dried. After completion, the obtained solid product is washed with ethanol and dried to obtain glucosamine hydrochloride product.

2. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (1), after adding the composite precipitant, the mass fraction of sodium chloride in the reaction system is 3~5.5%, and the mass fraction of sodium hydroxide is 0.5~0.8%.

3. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (1), the settling time is 20~35 minutes.

4. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (2), the sodium percarbonate reacts with the OH in the concentrated solution. - The molar ratio is 3~3.15:

1.

5. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (2), the liquid phase is heated and concentrated to 40-60% of its initial volume to obtain the concentrated liquid.

6. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (2), the settling time is 10~20 minutes.

7. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (2), the molar ratio of calcium nitrate to sodium carbonate in the system is 1:

1.

8. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (3), the liquid to be extracted is cooled to between 2 and 5°C.

9. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (3), the volume ratio of the extract to ethanol is 1:3 to 4.5, and the alcohol precipitation time is 30 to 40 minutes.

10. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (3), the solid product is washed with ethanol 2-3 times and then vacuum dried or freeze-dried to obtain the glucosamine hydrochloride product.

11. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (i), the heating temperature is 450~490℃ and the time is 30~50min.

12. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (i), the protective atmosphere includes either nitrogen or argon.

13. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (i), the ratio of the heat-treated product to the sodium bicarbonate solution is 1g:20~40ml.

14. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (i), the mass fraction of the sodium bicarbonate solution is 20-35%, and the standing time is 45-60 min.

15. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (ii), the ratio of the modified metastable hydrotalcite to the separation liquid is 1g:10~15ml.

16. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (ii), the ultrasonic treatment time is 25-40 min and the ultrasonic power is 300-450 W.

17. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (ii), the molar ratio of hydrochloric acid to bicarbonate in the liquid phase is 1:

1.

18. The purification and refining process for crude glucosamine hydrochloride according to claim 1, characterized in that, In step (ii), the solid product is washed with ethanol 2-3 times and then vacuum dried or freeze-dried to obtain the glucosamine hydrochloride product.

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