Method and system for preparing beta-hydroxy-beta-methylbutyric acid and salt thereof

Abstract

The invention discloses a method and a system for preparing beta-hydroxy-beta-methylbutyric acid and salts thereof, and the method specifically comprises the following steps: reacting diacetone alcohol with an oxidant solution to obtain a mixed solution, adjusting the pH value of the mixed solution to be less than or equal to 2, carrying out liquid separation treatment, and collecting a reaction solution containing beta-hydroxy-beta-methylbutyric acid to obtain the beta-hydroxy-beta-methylbutyric acid. Controlling the pH value of the reaction liquid to be less than or equal to 2, and performing electrodialysis treatment on the reaction liquid to obtain beta-hydroxy-beta-methylbutyric acid with relatively high purity. And mixing the prepared beta-hydroxy-beta-methylbutyric acid with at least one metal cation source reagent to obtain the salt of the beta-hydroxy-beta-methylbutyric acid. The preparation method provided by the invention has the characteristics of simple process, easy operation, high automation degree, high product yield and purity, easy realization of industrial production and the like, the purity of the prepared product can reach 98%, the recovery rate reaches 95%, multiple extraction processes or reduced pressure distillation treatment are avoided, and the method is suitable for industrial production. And the use of organic solvents and flammable and explosive reagents is reduced, so that the method is safer and more environment-friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of organic compound synthesis, and in particular to a method and system for preparing beta-hydroxy-beta-methylbutyric acid and salts thereof. Background Art

[0002] β-Hydroxy-β-methylbutyric acid (HMB, molecular formula C5H 10 O3) is an intermediate metabolite of the essential amino acid leucine. Experiments have shown that it can reduce the decomposition rate of protein molecules, increase the oxidation of animal fatty acids, and reduce fat, so it is often used as a sports supplement. Currently, most of the products sold on the market are β-hydroxy-β-methylbutyrate, mainly calcium salt and sodium salt, which are used to promote muscle volume growth.

[0003] In the prior art, the synthesis method of β-hydroxy-β-methylbutyric acid is usually based on the reaction of 4-methyl-4-hydroxy-2-pentanone (diacetone alcohol) with an oxidant, followed by acidification to obtain the target product. The specific process is as follows Figure 1 As shown, after the reaction of diacetone alcohol with an oxidant, it needs to be acidified with hydrochloric acid, and after separation, most of the water needs to be removed by distillation, and the salt is precipitated to make the extraction system reach a saturated state to improve the subsequent extraction efficiency, and then the salt is removed by filtration, and then it is acidified, extracted, and concentrated to obtain β-hydroxy-β-methylbutyric acid with high purity. The entire synthesis method is time-consuming and cumbersome to operate. At the same time, ethyl acetate with a relatively low boiling point is usually used in the extraction process, which not only has the risk of combustion and explosion, but also remains in the product and cannot be completely removed. On this basis, the preparation of β-hydroxy-β-methylbutyrate based on β-hydroxy-β-methylbutyric acid is also limited.

[0004] Therefore, there is an urgent need to provide a method for preparing β-hydroxy-β-methylbutyric acid and its salts to simplify the process operation, improve product quality, and meet industrial production requirements. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the present invention provides a method for preparing β-hydroxy-β-methylbutyric acid and its salts. The method has the characteristics of simple process, easy operation, high degree of automation, high yield and purity of the product, and easy to realize industrial production.

[0006] To this end, the first aspect of the present invention provides a method for preparing β-hydroxy-β-methylbutyric acid, comprising:

[0007] S1. reacting diacetone alcohol with an oxidant solution to obtain a mixed solution;

[0008] S2. adjusting the pH value of the mixed solution to be less than or equal to 2, performing liquid separation, and collecting the reaction solution containing β-hydroxy-β-methylbutyric acid;

[0009] S3. Control the pH value of the reaction solution to be less than or equal to 2, and perform electrodialysis on the reaction solution to obtain a desalted solution.

[0010] The solution obtained by acidification after the reaction of diacetone alcohol with an oxidant solution has a large salt content. The prior art mostly uses organic solvents for multiple extractions, but the purity of the obtained product is low and it is difficult to meet the needs of industrial production. The present invention utilizes the difference in the ionization constants of impurities and β-hydroxy-β-methylbutyric acid at different pH values, and controls the pH value to remove most of the impurities and salts through electrodialysis, while retaining the product. The crude HMB obtained by the method provided by the present invention has an HMB recovery rate of 95%, and the purity after salt formation can reach more than 98%. In addition, the method can also avoid the use of other organic reagents and flammable and explosive reagents, which is safer and more environmentally friendly than the prior art.

[0011] According to an embodiment of the present invention, step S3 further comprises: passing the reaction solution into a fresh water chamber of an electrodialysis device for electrodialysis treatment.

[0012] According to an embodiment of the present invention, the membrane voltage in the electrodialysis treatment is 0.5-4V.

[0013] According to an embodiment of the present invention, the temperature of the electrodialysis treatment is 20-30°C.

[0014] According to an embodiment of the present invention, the current density in the electrodialysis treatment is 25-300A / m 2 .

[0015] According to an embodiment of the present invention, the electrodialysis membrane used in the electrodialysis treatment includes a cation exchange membrane and an anion exchange membrane.

[0016] According to an embodiment of the present invention, the cation exchange membrane includes at least one selected from CTG-10, CT-4, and CTS.

[0017] According to an embodiment of the present invention, the anion exchange membrane includes at least one selected from ATG-10, CT-AHT, ATD, and ATS.

[0018] According to an embodiment of the present invention, the molar ratio of the diacetone alcohol to the oxidant in the oxidant solution in step S1 is (1:3)-(1:8).

[0019] According to an embodiment of the present invention, the oxidant includes at least one selected from hypochlorite, hypobromite, and hypoiodite.

[0020] According to an embodiment of the present invention, the oxidant is selected from at least one of sodium hypochlorite, calcium hypochlorite, sodium hypobromite, calcium hypobromite, sodium hypoiodite and calcium hypoiodite.

[0021] According to an embodiment of the present invention, the oxidant is selected from sodium hypochlorite or calcium hypochlorite, and the effective chlorine content in the oxidant solution is 8%-15%.

[0022] According to an embodiment of the present invention, the reaction temperature of step S1 is 0-10°C.

[0023] According to an embodiment of the present invention, the reaction time of step S1 is 8-12 hours.

[0024] According to an embodiment of the present invention, the method further comprises: S4. concentrating the desalted liquid.

[0025] The second aspect of the present invention provides a method for preparing β-hydroxy-β-methylbutyrate, comprising:

[0026] (1) preparing β-hydroxy-β-methylbutyric acid by the method according to the first aspect;

[0027] (2) mixing the β-hydroxy-β-methylbutyric acid with at least one metal cation source reagent to obtain the β-hydroxy-β-methylbutyric acid salt.

[0028] According to an embodiment of the present invention, the metal cation in the metal cation source reagent includes calcium ions or sodium ions.

[0029] According to an embodiment of the present invention, the metal cation source reagent includes at least one selected from calcium chloride, calcium hydroxide, calcium oxide, calcium carbonate, calcium acetate, sodium chloride, sodium hydroxide, sodium oxide, sodium carbonate, and sodium acetate.

[0030] The third aspect of the present invention provides a system for preparing β-hydroxy-β-methylbutyric acid, the system comprising a reaction device, a first pH value adjustment device, a phase separation device, a second pH value adjustment device, and an electrodialysis device;

[0031] Wherein, the reaction device is used to achieve the reaction of diacetone alcohol and oxidant solution to obtain a mixed solution;

[0032] The first pH value adjusting device is used to adjust the pH value of the mixed solution;

[0033] The phase separation device is used to achieve phase separation of the mixed solution treated by the first pH value adjusting device to obtain a reaction solution containing β-hydroxy-β-methylbutyric acid;

[0034] The second pH value adjusting device is used to adjust the pH value of the reaction solution;

[0035] The electrodialysis device is used to perform electrodialysis treatment on the reaction solution treated by the second pH value adjusting device.

[0036] The system can be used for the industrial preparation of β-hydroxy-β-methylbutyric acid, and the product obtained has higher purity and more ideal recovery rate.

[0037] According to an embodiment of the present invention, the electrodialysis device comprises a membrane pair, wherein the membrane pair comprises a cation exchange membrane, a fresh water chamber partition, an anion exchange membrane, and a concentrated water chamber partition to form a fresh water chamber and a concentrated water chamber respectively.

[0038] According to an embodiment of the present invention, the cation exchange membrane includes at least one selected from CTG-10, CT-4, and CTS.

[0039] According to an embodiment of the present invention, the anion exchange membrane includes at least one selected from ATG-10, CT-AHT, ATD, and ATS.

[0040] According to an embodiment of the present invention, the system further comprises a concentrating device, and the concentrating device is used to concentrate the reaction liquid treated by the electrodialysis.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] (1) Simple process. In the present invention, diacetone alcohol is reacted with an oxidant solution, and the pH value of the reaction solution is adjusted to be less than or equal to 2. After separation, the pH value of the reaction solution is controlled to be still less than or equal to 2, and an electrodialysis treatment is performed to obtain a solution containing β-hydroxy-β-methylbutyric acid, which is then concentrated to achieve a high-yield and high-purity β-hydroxy-β-methylbutyric acid product. Compared with the prior art, the process of multiple extractions or vacuum distillation treatment is avoided. At the same time, the present invention is simple to operate, has a high degree of automation, greatly improves production efficiency, and is conducive to the large-scale production of β-hydroxy-β-methylbutyric acid and its salts;

[0043] (2) High product quality. The preparation method provided by the present invention optimizes the post-processing operation of β-hydroxy-β-methylbutyric acid, effectively reduces the residual impurities and metal ions in the product, and the product purity can reach 98% and the recovery rate can reach 95%;

[0044] (3) Safer and more environmentally friendly. The preparation method provided by the present invention reduces the use of acidifying agents, extraction solvents and other reagents, and also reduces the use of flammable and explosive reagents, making the process conditions mild and easy to operate, reducing the production operation safety level, and reducing the discharge of industrial solid waste, which is more green and environmentally friendly and conducive to the realization of industrial production.

[0045] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0047] Figure 1 A flow chart of a synthesis method of β-hydroxy-β-methylbutyric acid in the prior art is shown;

[0048] Figure 2 The flow chart of the synthesis method of β-hydroxy-β-methylbutyric acid provided by the present invention is shown;

[0049] Figure 3 The schematic diagram shows the principle of electrodialysis in the method for synthesizing β-hydroxy-β-methylbutyric acid provided by the present invention. DETAILED DESCRIPTION

[0050] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0051] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0052] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0053] In order to make the present invention more easily understood, certain technical and scientific terms are specifically defined below. Unless otherwise clearly defined elsewhere in this document, all other technical and scientific terms used herein have the meanings commonly understood by those skilled in the art to which the present invention belongs.

[0054] In this document, the terms “include” or “comprising” are open expressions, that is, including the contents specified in the present invention but not excluding other contents.

[0055] As used herein, the terms "optionally", "optional" or "optionally" generally mean that the subsequently described event or circumstance may but need not occur, and that the description includes instances where the event or circumstance occurs and instances where it does not.

[0056] According to an embodiment of the present invention, the present invention provides a method for preparing β-hydroxy-β-methylbutyric acid, the specific process is as follows: Figure 2 As shown, including:

[0057] S1. reacting diacetone alcohol with an oxidant solution to obtain a mixed solution;

[0058] S2. adjusting the pH value of the mixed solution to be less than or equal to 2, performing liquid separation, and collecting the reaction solution containing β-hydroxy-β-methylbutyric acid;

[0059] S3. Controlling the pH value of the reaction solution to be less than or equal to 2, subjecting the reaction solution to electrodialysis to obtain a desalted solution;

[0060] S4. Concentrating the desalted liquid.

[0061] The preparation method of β-hydroxy-β-methylbutyric acid provided by the present invention replaces the organic solvent method widely used in the prior art with electrodialysis treatment in post-treatment. The purity of the product prepared by the method provided by the present invention can reach 98%, and the recovery rate can reach 95%.

[0062] According to an embodiment of the present invention, the molar ratio of the diacetone alcohol to the oxidant in the oxidant solution in step S1 is (1:3)-(1:8) to ensure the full conversion of the diacetone alcohol. The types of oxidants include but are not limited to hypochlorites, hypobromites, and hypoiodites, and can be specifically selected from at least one of sodium hypochlorite, calcium hypochlorite, sodium hypobromite, calcium hypobromite, sodium hypoiodite, and calcium hypoiodite. When hypochlorite is selected, the effective chlorine content in the solution is 8%-15%, that is, the mass percentage of the chlorine element contained in the solution is 8%-15%. The chloroform reaction in step S1 is a highly exothermic reaction. A higher reaction temperature will degrade the product and produce by-products. The temperature is controlled to be 0-10°C to reduce the occurrence of side reactions. The specific reaction time can be 8-12h.

[0063] According to an embodiment of the present invention, after the reaction in step S1 is complete, an acidic solution may be added to the mixed solution under stirring to adjust the pH value to be less than or equal to 2. The acidic solution used may be a commonly used acidic solution such as hydrochloric acid. After standing for a period of time, liquid separation is performed to separate chloroform and collect the reaction solution containing β-hydroxy-β-methylbutyric acid.

[0064] According to an embodiment of the present invention, before the reaction solution is subjected to electrodialysis treatment, the reaction solution may be diluted to reduce the salt concentration in the reaction solution to prevent precipitation during the electrodialysis process. The pH value of the reaction solution is controlled to be less than or equal to 2, and the reaction solution is transferred to the fresh water chamber in the electrodialysis device for electrodialysis treatment. Figure 3 As shown. Under the action of the electric field, cations such as sodium ions in the reaction solution pass through the cation exchange membrane, and anions such as chloride ions pass through the anion exchange membrane, and migrate from the fresh water chamber to the concentrated water chamber, while the electrically neutral substances remain in the fresh water chamber to achieve desalination. The fresh water chamber of the electrodialysis device obtains a crude β-hydroxy-β-methylbutyric acid aqueous solution, and the concentrated water chamber obtains impurities. The crude β-hydroxy-β-methylbutyric acid aqueous solution is then concentrated to obtain pure β-hydroxy-β-methylbutyric acid. The current density during the electrodialysis treatment is 25-300A / m 2 , the membrane voltage is 0.5-4V, the temperature is controlled at 20-30℃, and can be reasonably selected and adjusted according to the actual preparation situation. The initial conductivity of the reaction solution is 140-180ms / cm. When the conductivity of the aqueous solution in the fresh water chamber of the electrodialysis device is less than 20μS / cm, the ion exchange is stopped.

[0065] The present invention has no restrictions on the type and model of the electrodialysis membrane. Various types of anion and cation exchange membranes prepared from commercially available organic materials can be used as membrane materials for the electrodialysis device used in the present invention. The cation exchange membrane can be selected but not limited to CTG-10, CT-4, CTS, and the anion exchange membrane can be selected but not limited to ATG-10, CT-AHT, ATD, ATS. At the same time, there is no restriction on the structure and model of the electrodialysis device. For example, the separator type and electrode type of the electrodialysis device do not affect the implementation results of the preparation process of the present invention. Specifically, the DSAJ-IV model can be selected but not limited to it.

[0066] According to the embodiments of the present invention, sampling and testing can be performed during the actual preparation process, such as sampling and testing the mixed solution and sampling and testing the acidified solution, and the next step can be performed after the test is qualified.

[0067] According to a specific embodiment of the present invention, β-hydroxy-β-methylbutyric acid can be prepared by the following method:

[0068] Add 1800 mol of sodium hypochlorite to the reactor, wherein the effective chlorine content of the sodium hypochlorite solution is 8%-15%, cool the solution temperature to below 3°C, slowly add 300 mol of diacetone alcohol to the reactor, control the temperature below 10°C during the reaction, and keep warm for 2 hours. After the reaction is complete, add an acidic solution under stirring until the pH of the reaction solution is less than or equal to 2, let it stand for a period of time, perform liquid separation, and separate the chloroform. Add water to the reaction solution for dilution, control the pH value of the reaction solution to be less than or equal to 2, and transfer the material to an electrodialysis device for desalination and impurity removal. The specific electrodialysis treatment parameters are as follows: the membrane pair voltage of the electrodialysis device is 0.5~4V, and the current density is 25~300A / m 2 , temperature 20-30°C, initial conductivity 140-180ms / cm, when the conductivity of the aqueous solution in the fresh water chamber of the electrodialysis device is less than 20μS / cm, ion exchange is stopped to obtain a desalted solution, in which the β-hydroxy-β-methylbutyric acid content is 48.6g / L.

[0069] According to an embodiment of the present invention, the present invention also provides a method for preparing β-hydroxy-β-methylbutyrate, comprising:

[0070] (1) preparing β-hydroxy-β-methylbutyric acid by the aforementioned method;

[0071] (2) mixing the β-hydroxy-β-methylbutyric acid with at least one metal cation source reagent to obtain the β-hydroxy-β-methylbutyric acid salt.

[0072] The preparation of β-hydroxy-β-methylbutyrate is based on the preparation of β-hydroxy-β-methylbutyric acid, and β-hydroxy-β-methylbutyric acid is mixed with at least one metal cation source reagent to obtain the β-hydroxy-β-methylbutyrate. The metal cation in the metal cation source reagent includes but is not limited to calcium ions or sodium ions, and the metal cation source reagent includes at least one selected from calcium chloride, calcium hydroxide, calcium oxide, calcium carbonate, calcium acetate, sodium chloride, sodium hydroxide, sodium oxide, sodium carbonate, and sodium acetate.

[0073] According to an embodiment of the present invention, the preparation method of β-hydroxy-β-methylbutyrate may further include filtering, concentrating, recrystallizing and other steps of the β-hydroxy-β-methylbutyrate to obtain pure β-hydroxy-β-methylbutyrate, and the recrystallization solvent may be ethanol, acetone and other solvents.

[0074] The scheme of the present invention will be explained below in conjunction with the embodiments. It will be appreciated by those skilled in the art that the following embodiments are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. Where specific techniques or conditions are not indicated in the embodiments, the techniques or conditions described in the literature in this area or the product specifications are used. The reagents or instruments used are not indicated by the manufacturer and are all conventional products that can be obtained commercially.

[0075] Example 1: Preparation of β-hydroxy-β-methylbutyric acid

[0076] Step 1: add 1800 mol of sodium hypochlorite into the reactor, wherein the effective chlorine content of the sodium hypochlorite solution is 8%-15%, cool the solution temperature to below 3°C, slowly add 300 mol of diacetone alcohol into the reactor, control the temperature below 10°C during the reaction, and keep warm for 2 hours;

[0077] Step 2: After the reaction is complete, add an acidic solution under stirring until the pH of the reaction solution is less than or equal to 2, let it stand for a period of time, perform liquid separation, separate the chloroform, and obtain a solution containing β-hydroxy-β-methylbutyric acid and its salt;

[0078] Step 3: Take 5 portions (500 ml) of the mixed solution obtained in step 2 (β-hydroxy-β-methylbutyric acid content: 20-40 g / L, salt content: 100-200 g / L, impurity content unknown), and number them 1, 2, 3, 4, and 5 respectively. The pH values ​​are controlled to be 5.0, 4.0, 3.0, 2.0, and 1.0 respectively by dilution and acid addition, and the diluted and pH-adjusted material is transferred to the electrodialysis device for desalination and impurity removal. The specific electrodialysis treatment parameters are as follows: the membrane voltage of the electrodialysis device is 0.5-4 V, and the current density is 25-300 A / m 2 , temperature 20-30°C, initial conductivity 140-180ms / cm, when the conductivity of the aqueous solution in the fresh water chamber of the electrodialysis device is less than 20μS / cm, ion exchange is stopped to obtain a desalted solution, and the obtained desalted solution is concentrated under reduced pressure at 60-80°C to obtain crude HMB.

[0079] After electrodialysis treatment and concentration, the product content and recovery rate are shown in Table 1:

[0080] Table 1 Results of pH selection of mixed solution in acidification step

[0081] serial number pH Impurity content β-Hydroxy-β-methylbutyric acid content Yield of β-hydroxy-β-methylbutyric acid 1 5.0 44％ 56％ 10％ 2 4.0 37％ 63％ 30％ 3 3.0 25％ 75％ 70％ 4 2.0 15％ 85％ 95％ 5 1.0 15％ 85％ 95％

[0082] Example 2: Preparation of β-hydroxy-β-methylbutyrate

[0083] The product corresponding to No. 4 in Example 1 was transferred to a neutralization kettle, 95% ethanol was added and stirred, and then calcium hydroxide was added to adjust the pH value to 7-8, the temperature was raised to 70° C., and the temperature was kept for 2 hours. The material was filtered into a crystallization kettle, cooled to 5° C., slowly cooled and crystallized, centrifuged, and dried to obtain β-hydroxy-β-methylbutyric acid calcium salt (CaHMB) with a purity of 98%.

[0084] Comparative Example: Preparation of β-hydroxy-β-methylbutyric acid by conventional method

[0085] (1) The β-hydroxy-β-methylbutyric acid reaction solution is concentrated, desalted, acidified, and then added to an extraction kettle, wherein the β-hydroxy-β-methylbutyric acid content is 60-100 g / L. To improve the extraction rate, the above solution is extracted three times with ethyl acetate, each extraction using 1 / 2 of the reaction solution volume of ethyl acetate, and the three extractions are combined;

[0086] (2) The ethyl acetate after the extraction is pumped into a crude distillation kettle. The ethyl acetate is basically removed by vacuum distillation (pressure -0.08 to -0.1 MPa) at a distillation temperature below 40°C. After the distillation is completed, a crude β-hydroxy-β-methylbutyric acid product is obtained, wherein the β-hydroxy-β-methylbutyric acid content is 85%, the impurity content is 15%, and the recovery rate is 90%. The results of each extraction are shown in Table 2:

[0087] Table 2 Experimental results of traditional preparation method

[0088] Extraction times Impurity content β-Hydroxy-β-methylbutyric acid content Recovery rate of β-hydroxy-β-methylbutyric acid 1 12％ 88％ 65.0％ 2 21％ 79％ 18.4％ 3 28％ 62％ 6.6％ After extraction and merging 15％ 85％ 90％

[0089] It can be seen that the traditional preparation method, that is, the extraction method, cannot achieve high product purity and recovery rate. Compared with the preparation method provided by the present invention, it not only requires multiple extractions, but also uses ethyl acetate, a flammable and explosive reagent, and cannot meet the requirements of industrial production for the purity and recovery rate of β-hydroxy-β-methylbutyric acid.

[0090] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", "some implementation schemes" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0091] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing β-hydroxy-β-methylbutyric acid, characterized in that: include: S1. reacting diacetone alcohol with an oxidant solution to obtain a mixed solution; S2. adjusting the pH value of the mixed solution to be less than or equal to 2, performing liquid separation, and collecting the reaction solution containing β-hydroxy-β-methylbutyric acid; S3. Control the pH value of the reaction solution to be less than or equal to 2, and perform electrodialysis on the reaction solution to obtain a desalted solution.

2. The method according to claim 1, characterized in that Step S3 further comprises: passing the reaction solution into the fresh water chamber of the electrodialysis device for electrodialysis treatment; Optionally, the membrane voltage in the electrodialysis treatment is 0.5-4V; Optionally, the temperature of the electrodialysis treatment is 20-30°C.

3. The method according to claim 1, characterized in that The current density in the electrodialysis treatment is 25-300A / m 2 .

4. The method according to claim 1, characterized in that: The electrodialysis membrane used in the electrodialysis treatment includes a cation exchange membrane and an anion exchange membrane; Optionally, the cation exchange membrane comprises at least one selected from CTG-10, CT-4, and CTS; Optionally, the anion exchange membrane comprises at least one selected from ATG-10, CT-AHT, ATD, and ATS.

5. The method according to claim 1, characterized in that: The molar ratio of diacetone alcohol to the oxidant in the oxidant solution in step S1 is (1:3)-(1:8); Optionally, the oxidant comprises at least one selected from hypochlorite, hypobromite, and hypoiodite; Optionally, the oxidant is selected from at least one of sodium hypochlorite, calcium hypochlorite, sodium hypobromite, calcium hypobromite, sodium hypoiodite, and calcium hypoiodite; Optionally, the oxidant is selected from sodium hypochlorite or calcium hypochlorite, and the effective chlorine content in the oxidant solution is 8%-15%; Optionally, the reaction temperature of step S1 is 0-10°C; Optionally, the reaction time of step S1 is 8-12 hours.

6. The method according to claim 1, characterized in that The method further comprises: S4. Concentrating the desalted liquid.

7. A method for preparing β-hydroxy-β-methylbutyrate, characterized in that: include: (1) preparing β-hydroxy-β-methylbutyric acid by the method according to any one of claims 1 to 6; (2) mixing the β-hydroxy-β-methylbutyric acid with at least one metal cation source reagent to obtain the β-hydroxy-β-methylbutyric acid salt.

8. The method according to claim 7, characterized in that The metal cation in the metal cation source reagent includes calcium ions or sodium ions; Optionally, the metal cation source reagent includes at least one selected from calcium chloride, calcium hydroxide, calcium oxide, calcium carbonate, calcium acetate, sodium chloride, sodium hydroxide, sodium oxide, sodium carbonate, and sodium acetate.

9. A system for preparing β-hydroxy-β-methylbutyric acid, characterized in that: The system comprises a reaction device, a first pH value adjusting device, a phase separation device, a second pH value adjusting device, and an electrodialysis device; Wherein, the reaction device is used to achieve the reaction of diacetone alcohol and oxidant solution to obtain a mixed solution; The first pH value adjusting device is used to adjust the pH value of the mixed solution; The phase separation device is used to achieve phase separation of the mixed solution treated by the first pH value adjusting device to obtain a reaction solution containing β-hydroxy-β-methylbutyric acid; The second pH value adjusting device is used to adjust the pH value of the reaction solution; The electrodialysis device is used to perform electrodialysis treatment on the reaction solution treated by the second pH value adjusting device.

10. The system according to claim 9, characterized in that The electrodialysis device comprises a membrane pair, wherein the membrane pair comprises a cation exchange membrane, a fresh water chamber partition, an anion exchange membrane, and a concentrated water chamber partition to form a fresh water chamber and a concentrated water chamber respectively; Optionally, the cation exchange membrane comprises at least one selected from CTG-10, CT-4, and CTS; Optionally, the anion exchange membrane comprises at least one selected from ATG-10, CT-AHT, ATD, and ATS; Optionally, the system further comprises a concentrating device, and the concentrating device is used to concentrate the reaction solution treated by electrodialysis.

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