Calcium glucarate refining method

Abstract

The invention belongs to the technical field of chemical processes, and particularly relates to a calcium glucarate refining method. The method comprises two refining processes, namely washing a calcium glucarate product with pure water, pulping to obtain primary refining, performing secondary refining by adopting a mixed solution, and finally drying and weighing to obtain a refined product of the calcium glucarate. According to the calcium glucarate refining method provided by the invention, the purity of the prepared calcium glucarate reaches 99% or above, and the yield is 81.9%-87.2%. The refining method is easy to operate, high in flexibility and low in cost, meanwhile, waste liquid generated in the production process cannot pollute the environment after being treated, and the refining method is suitable for industrial production.

Description

Technical Field

[0001] The present invention belongs to the technical field of chemical processes, and particularly relates to a method for refining calcium glucarate. Background Art

[0002] Calcium glucarate is an important high-value-added chemical, which has a wide range of applications in the fields of industry, food, medicine, health care and textiles. It can be used as a biodegradable cleaner, metal complexing agent, binder and plant fertilizer. In addition, in the medical field, calcium glucarate tetrahydrate can act as a stabilizer in calcium gluconate injection, enabling calcium gluconate to stably exist in a supersaturated aqueous solution without crystallization; it can also be used as a calcium supplement and preservative in functional milk powder.

[0003] Calcium glucarate is converted into glucaric acid in the body and utilized by the human body. More and more studies have found that glucaric acid in the body not only plays an important role in maintaining normal cholesterol levels, but also has the function of protecting the cardiovascular system, and at the same time it shows certain potential in the clinical treatment of diabetes. With the increasing expansion of the application field of calcium glucarate, its demand is also gradually increasing. Therefore, the production of high-quality and high-purity calcium glucarate has become an urgent pursuit of enterprises. The production of calcium glucarate mainly consists of two parts: synthesis and refining. Currently, the existing methods for refining calcium glucarate still have defects such as cumbersome process operations, product contamination caused by multiple operations, and unstable precision filtration effects. Summary of the Invention

[0004] Most calcium glucarates require the use of calcium salts of glucaric acid. In view of the problems existing in the background art, the present invention provides a method for refining calcium glucarate to obtain calcium glucarate with a relatively high purity.

[0005] The technical solution adopted by the present invention to solve its technical problems is as follows:

[0006] Step (a): Wash the crude calcium glucarate with pure water 3 times, transfer it after reduced-pressure drying to a reaction flask;

[0007] Step (b): Add ethanol to the reaction flask for slurry purification, filter and drain to obtain an off-white solid, and perform secondary refining after vacuum drying;

[0008] Step (c): Add a small amount of purified water to the first refined product, dropwise add hydrochloric acid, stir and dissolve it at (50 ± 5) °C, and sieve;

[0009] Step (d): Wash the filter cake with a small amount of ethanol, and dry it by blowing air for 12 - 18 hours to obtain a white solid of calcium glucarate;

[0010] Step (e): Filter the remaining waste liquid to make it acidic, add sodium bicarbonate solution thereto, adjust the pH value of the waste residue to 7 by the acid-base neutralization method, and discharge it.

[0011] Preferably, the operation steps of beating in step (b) are as follows: Grind the crude calcium glucarate into fine particles and suspend them in ethanol, stir at 35 °C for 20 - 30 minutes, perform vacuum filtration to obtain a solid, and wash the filter cake with a small amount of ethanol three times.

[0012] Preferably, the vacuum drying conditions in step (b) are: drying at 30 - 35 °C for 24 hours.

[0013] Preferably, the specific operation method in step (c) is: Load calcium glucarate into a three-necked flask containing purified water, add hydrochloric acid dropwise to control the pH ≤ 3 to redissolve the crude product, stir for 30 minutes after the addition is complete, and perform preliminary filtration on the redissolved solution.

[0014] More preferably, the solution sieving in step (c) is a coarse filter with a 300-mesh filter cloth.

[0015] Based on the above solution, the product purity of the finally prepared calcium glucarate > 99%.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0017] The calcium glucarate refining method provided by the present invention, through two refinements, that is, after removing small-polar organic solvents by beating with a single solvent, further performing secondary refinement with a mixed solvent, the purity of the prepared calcium glucarate reaches more than 99%, the yield is between 81.9% and 87.2%, and with the continuous increase of the feed, the yield does not decrease significantly, indicating that this method is suitable for industrial production. At the same time, this refining method also has the advantages of simple operation, strong flexibility, and low cost. Specific Embodiments

[0018] The embodiments of the technical solution of the present invention will be described in detail below in conjunction with the embodiments. The following embodiments are only used to illustrate the technical solution of the present invention more clearly, so they are only examples and cannot be used to limit the protection scope of the present invention.

[0019] It should be noted that the experimental methods used in the implementation examples are all conventional methods unless otherwise specified; the materials, reagents, etc. used, unless otherwise specified, can all be obtained from commercial channels.

[0020] In the present invention, unless otherwise specified, the numerical range "a to b" represents an abbreviated representation of any combination of real numbers between a and b, where both a and b are real numbers. For example, the numerical range "0 to 5" means that all real numbers between "0 to 5" are fully listed herein, and "0 to 5" is only an abbreviated representation of these numerical combinations.

[0021] In the present invention, if there is no special description, all the embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution.

[0022] In the present invention, if there is no special description, all the steps mentioned herein can be carried out in sequence or randomly, but preferably in sequence; for example, the method includes steps (a) and (b), which means that the method can include steps (a) and (b) carried out in sequence, or can also include steps (b) and (a) carried out in sequence; for example, it is mentioned that the method may further include step (c), which means that step (c) can be added to the method in any order. For example, the method can include steps (a), (b) and (c), or can also include steps (a), (c) and (b), or can also include steps (c), (a) and (b), etc.

[0023] In the present invention, if there is no special description, the specific numerical values and specific substances in the embodiments of the present invention can be combined with other features in the description part of the present invention; for example, if the specification mentions that the reaction temperature is 10 to 100 °C, and the reaction temperature mentioned in the embodiment is 20 °C, then it can be considered that the present invention has specifically disclosed the range of 10 to 20 °C, or the range of 20 to 100 °C, and this range can be combined with other features in the description part to form a new technical solution.

[0024] Example 1

[0025] 5 kg of crude calcium glucarate is washed 3 times with pure water and dried under reduced pressure. Subsequently, the crude calcium glucarate is ground into fine particles and suspended in ethanol, stirred at 35 °C for 20 minutes, and filtered under reduced pressure to obtain a solid. The filter cake is washed 3 times with a small amount of ethanol and vacuum dried at 35 °C for 24 hours and then subjected to secondary purification; the first refined product is added to a three-necked flask containing purified water. At 55 °C, hydrochloric acid is slowly added dropwise to control the pH ≤ 3 to redissolve the crude product. After the addition is completed, it is stirred for 30 minutes, and the heavy solution is filtered through a coarse filter with a 300-mesh filter cloth. The filter cake is washed with a small amount of ethanol and dried by blowing for 12 hours to obtain a white solid of calcium glucarate; weighing gives 4.36 kg of the product, and the yield is 87.2%. The waste liquid remaining after filtration is acidic. Sodium bicarbonate solution is added thereto, and the pH value of the waste residue is adjusted to 7 by the acid-base neutralization method and then discharged.

[0026] Example 2

[0027] 5 kg of crude calcium glucarate was washed 3 times with pure water and dried under reduced pressure. Subsequently, the crude calcium glucarate was ground into fine particles and suspended in ethanol, stirred at 35 °C for 30 minutes, and filtered under reduced pressure to obtain a solid. The filter cake was washed 3 times with a small amount of ethanol and vacuum dried at 35 °C for 24 hours, followed by secondary purification. The first refined product was added to a three-necked flask containing purified water. At 50 °C, hydrochloric acid was slowly added dropwise to control the pH ≤ 3 to redissolve the crude product. After the addition was complete, it was stirred for 30 minutes, and the heavy solution was filtered through a coarse filter with a 300-mesh filter cloth. The filter cake was washed with a small amount of ethanol and dried by blowing for 15 hours to obtain a white solid of calcium glucarate. Weighing gave 4.28 kg of the product, and the yield was 85.6%. The waste liquid remaining after filtration was acidic. Sodium bicarbonate solution was added thereto, and the pH value of the waste residue was adjusted to 7 by the acid-base neutralization method and then discharged.

[0028] Example 3

[0029] 15 kg of crude calcium glucarate was washed 3 times with pure water and dried under reduced pressure. Subsequently, the crude calcium glucarate was ground into fine particles and suspended in ethanol, stirred at 35 °C for 30 minutes, and filtered under reduced pressure to obtain a solid. The filter cake was washed 3 times with a small amount of ethanol and vacuum dried at 35 °C for 24 hours, followed by secondary purification. The first refined product was added to a three-necked flask containing purified water. At 55 °C, hydrochloric acid was slowly added dropwise to control the pH ≤ 3 to redissolve the crude product. After the addition was complete, it was stirred for 30 minutes, and the heavy solution was filtered through a coarse filter with a 300-mesh filter cloth. The filter cake was washed with a small amount of ethanol and dried by blowing for 12 hours to obtain a white solid of calcium glucarate. Weighing gave 12.39 kg of the product, and the yield was 82.6%. The waste liquid remaining after filtration was acidic. Sodium bicarbonate solution was added thereto, and the pH value of the waste residue was adjusted to 7 by the acid-base neutralization method and then discharged.

[0030] Example 4

[0031] 5 kg of crude calcium glucarate was washed 3 times with pure water and dried under reduced pressure. Subsequently, the crude calcium glucarate was ground into fine particles and suspended in ethanol, stirred at 35 °C for 25 minutes, and filtered under reduced pressure to obtain a solid. The filter cake was washed 3 times with a small amount of ethanol and vacuum dried at 35 °C for 24 hours, followed by secondary purification. The first refined product was added to a three-necked flask containing purified water. At 55 °C, hydrochloric acid was slowly added dropwise to control the pH ≤ 3 to redissolve the crude product. After the addition was complete, it was stirred for 30 minutes, and the heavy solution was filtered through a coarse filter with a 300-mesh filter cloth. The filter cake was washed with a small amount of ethanol and dried by blowing for 18 hours to obtain a white solid of calcium glucarate. Weighing gave 4.34 kg of the product, and the yield was 86.8%. The waste liquid remaining after filtration was acidic. Sodium bicarbonate solution was added thereto, and the pH value of the waste residue was adjusted to 7 by the acid-base neutralization method and then discharged.

[0032] Example 5

[0033] 50 kg of crude calcium glucarate was washed 3 times with pure water and dried under reduced pressure. Subsequently, the crude calcium glucarate was ground into fine particles and suspended in ethanol. It was stirred at 35 °C for 30 minutes, and then filtered under reduced pressure to obtain a solid. The filter cake was washed 3 times with a small amount of ethanol and vacuum dried at 35 °C for 24 hours before secondary purification; The first refined product was added to a three-necked flask containing purified water. At 55 °C, hydrochloric acid was slowly added dropwise to control the pH ≤ 3 to redissolve the crude product. After the addition was completed, it was stirred for 30 minutes, and the heavy solution was filtered through a coarse filter with a 300-mesh filter cloth. The filter cake was washed with a small amount of ethanol and dried by blowing for 12 hours to obtain a white solid of calcium glucarate; Weighing obtained 40.95 kg of the product, and the yield was 81.9%. The waste liquid remaining after filtration was acidic. Sodium bicarbonate solution was added to it, and the pH value of the waste residue was adjusted to 7 by the acid-base neutralization method and then discharged.

[0034] Example 6

[0035] 25 kg of crude calcium glucarate was washed 3 times with pure water and dried under reduced pressure. Subsequently, the crude calcium glucarate was ground into fine particles and suspended in ethanol. It was stirred at 35 °C for 20 minutes, and then filtered under reduced pressure to obtain a solid. The filter cake was washed 3 times with a small amount of ethanol and vacuum dried at 35 °C for 24 hours before secondary purification; The first refined product was added to a three-necked flask containing purified water. At 50 °C, hydrochloric acid was slowly added dropwise to control the pH ≤ 3 to redissolve the crude product. After the addition was completed, it was stirred for 30 minutes, and the heavy solution was filtered through a coarse filter with a 300-mesh filter cloth. The filter cake was washed with a small amount of ethanol and dried by blowing for 15 hours to obtain a white solid of calcium glucarate; Weighing obtained 21.08 kg of the product, and the yield was 84.3%. The waste liquid remaining after filtration was acidic. Sodium bicarbonate solution was added to it, and the pH value of the waste residue was adjusted to 7 by the acid-base neutralization method and then discharged.

[0036] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; Although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: They can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be covered by the scope of the claims and the description of the present invention.

Claims

1. A method for refining calcium glucarate, characterized in that: The following steps are involved: Step (a): Wash the crude calcium glucarate with pure water three times, dry under reduced pressure and transfer to a reaction bottle; Step (b): Add ethanol to the reaction bottle for pulping and purification, filter and drain to obtain an off-white solid, and perform secondary purification after vacuum drying; Step (c): add the first refined product into a small amount of purified water, add hydrochloric acid dropwise, stir at (50±5)°C to dissolve, and sieve; Step (d): washing the filter cake with a small amount of ethanol and air drying for 12 to 18 hours to obtain a white solid of calcium glucarate; Step (e): The residual waste liquid after filtration is acidic and cannot be discharged directly, so sodium bicarbonate solution is added thereto, and the pH value of the waste residue is adjusted to 7 by acid-base neutralization method before discharge.

2. A method for refining calcium glucarate according to claim 1, characterized in that: The operation steps of the beating in step (b) are as follows: grinding the crude calcium glucarate into fine particles and suspending them in ethanol, stirring at 35° C. for 20 to 30 minutes, filtering under reduced pressure to obtain a solid, and washing the filter cake three times with a small amount of ethanol.

3. A method for refining calcium glucarate according to claim 1, characterized in that, The vacuum drying conditions of step (b) are: drying at 30-35° C. for 24 hours.

4. A method for refining calcium glucarate according to claim 1, characterized in that, The specific operation method of step (c) is as follows: calcium glucarate is added into a three-necked bottle filled with purified water, hydrochloric acid is added dropwise to control the pH value to ≤ 3 to redissolve the crude product, and after the addition is completed, the mixture is stirred at (50±5)° C. for 30 minutes to dissolve the crude product, and the heavy solution is filtered.

5. A method for refining calcium glucarate according to claim 4, characterized in that, In the step (c), the solution is screened through a coarse filter with a 300-mesh filter cloth.

6. A method for refining calcium glucarate according to claim 1, characterized in that, In the step (d), the product purity of calcium glucarate is greater than 99%.