Hydrolysis control method for preparing high-purity D-cystine
Through the gradient hydrolysis method and the addition of hydrochloric acid and acetic acid, the hydrolysis process of D-2,2-dimethyltetrahydrothiazole-4-carboxylic acid-L-tartrate was optimized, and the purity of D-cystine was successfully improved, solving the problem of low purity in the prior art.
Patent Information
- Application Number
- CN202411856106.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-17
- Publication Date
- 2025-04-25
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
The prior art is difficult to effectively prepare high-purity D-cystine, and poor control of the hydrolysis process leads to low purity.
D-2,2-dimethyltetrahydrothiazole-4-carboxylic acid-L-tartrate was hydrolyzed by gradient hydrolysis. By adding hydrochloric acid and acetic acid during the hydrolysis process, and adjusting the pH value and hydrolysis temperature, the purity of D-cystine was gradually improved.
Through this method, the purity of D-cystine can be significantly improved to reach 99.3%, solving the problem of low purity in the prior art.
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Abstract
Description
Technical Field
[0001] The invention relates to the technical field of organic chemical synthesis, and in particular to a hydrolysis control method for preparing high-purity D-cystine. Background Art
[0002] D-cystine is a non-natural amino acid that does not naturally exist in proteins. Compared with the natural amino acid L-cystine, D-cystine has not only the basic functions of L-cystine, but also excellent properties that L-cystine does not have, and has broad application prospects in the fields of biomedicine, cosmetics, food additives, etc. However, the physical and chemical properties of D-cystine and L-cystine are almost the same under general conditions. Therefore, the preparation of high-purity D-cystine has always been a research hotspot for those skilled in the art.
[0003] An existing method for preparing D-cystine is to use D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate as a raw material, prepare D-cysteine by hydrolysis, and then prepare D-cystine by oxidation. The hydrolysis process of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate is the key to determining whether high-purity D-cystine can be prepared. Therefore, providing a hydrolysis control method for preparing high-purity D-cystine has become a technical problem to be solved urgently by those skilled in the art. Summary of the invention
[0004] The purpose of the present invention is to provide a hydrolysis control method for preparing high-purity D-cystine, which can optimize the hydrolysis of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate, thereby preparing high-purity D-cystine.
[0005] To achieve the above object, the present invention provides the following technical solutions:
[0006] A hydrolysis control method for preparing high-purity D-cystine comprises the following steps:
[0007] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution to obtain a mixed solution;
[0008] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0009] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5, allowing it to stand, filtering it with suction, and retaining the filtrate;
[0010] 4) adding hydrogen peroxide dropwise to the filtrate obtained in step 3), allowing the mixture to stand, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
[0011] Furthermore, in step 1), the mass volume ratio of the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water is 1 g: 20 mL.
[0012] Furthermore, in step 1), the concentration of the hydrochloric acid is 0.05 to 0.10 mol·L -1 .
[0013] Furthermore, in step 1), the concentration of acetic acid is 0.10 to 0.30 mol·L -1 .
[0014] Furthermore, in step 1), the volume ratio of the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid is 20:1:2.
[0015] Furthermore, in step 2), the gradient hydrolysis is as follows: hydrolysis at 0-4°C for 10 min, hydrolysis at 20-25°C for 5 min, and hydrolysis at 30-35°C for 20 min.
[0016] Furthermore, in step 3), the standing time is 60 minutes.
[0017] Furthermore, in step 4), the volume fraction of the hydrogen peroxide is 20%.
[0018] Furthermore, in step 4), the volume ratio of the filtrate to hydrogen peroxide is 15:1.
[0019] Furthermore, in step 4), the standing time is 30 minutes.
[0020] Compared with the prior art, the present invention has the following beneficial effects:
[0021] The invention provides a hydrolysis control method for preparing high-purity D-cystine. D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate is used as a raw material, and gradient hydrolysis is performed in the presence of hydrochloric acid and acetic acid to obtain high-purity D-cystine. According to detection, the purity of D-cystine prepared by the hydrolysis control method for preparing high-purity D-cystine provided by the invention can reach 99.3%. DETAILED DESCRIPTION
[0022] Now, various exemplary embodiments of the present invention are described in detail, and this detailed description should not be considered as a limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and embodiments of the present invention. It should be understood that the terms described in the present invention are only for describing specific embodiments and are not used to limit the present invention.
[0023] In addition, for the numerical range in the present invention, it is understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Each smaller range between the intermediate value in any stated value or stated range and any other stated value or intermediate value in the range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.
[0024] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.
[0025] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to the skilled artisan. The present invention description and examples are exemplary only.
[0026] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.
[0027] In the following examples, the preparation method of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate comprises the following steps:
[0028] 1) adding L-cysteine, L-tartaric acid and acetone to glacial acetic acid in a molar ratio of 1:1:5:8, and stirring at 60°C for 30 minutes;
[0029] 2) After the reaction in step 1) is completed, salicylaldehyde is added to the reaction system in step 1) at a molar ratio of salicylaldehyde to L-cysteine of 1:10, and the reaction is continued for 15 hours, cooled in an ice-water bath for 30 minutes, filtered, and washed with ethyl acetate to obtain the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate.
[0030] In the following examples, a hydrolysis control method for preparing high-purity D-cystine comprises the following steps:
[0031] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0032] Wherein, the concentration of the hydrochloric acid is 0.05~0.10mol·L -1 ; The concentration of the acetic acid is 0.10 to 0.30 mol·L -1 ;
[0033] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0034] The gradient hydrolysis is as follows: hydrolysis at 0-4°C for 10 min, hydrolysis at 20-25°C for 5 min, and hydrolysis at 30-35°C for 20 min;
[0035] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0036] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
[0037] Examples 1 to 6
[0038] A high purity D-cystine
[0039] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0040] The concentration of hydrochloric acid is shown in Table 1; the concentration of acetic acid is 0.10 mol·L -1 ;
[0041] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0042] The gradient hydrolysis is as follows: hydrolysis at 0°C for 10 min, hydrolysis at 20°C for 5 min, and hydrolysis at 30°C for 20 min;
[0043] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0044] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
[0045] Table 1 Concentration of hydrochloric acid
[0046]
[0047] The purity of the high-purity D-cystine prepared in Examples 1 to 6 was tested, and the test results are shown in Table 2;
[0048] Table 2 Purity
[0049]
[0050] It can be seen from the data in Table 2 that the hydrolysis control method for preparing high-purity D-cystine provided by the present invention effectively improves the purity of the finally prepared D-cystine by adjusting the concentration of hydrochloric acid in the mixed solution; moreover, as the concentration of hydrochloric acid increases, the purity of D-cystine first increases and then decreases. When the concentration of hydrochloric acid is 0.08 mol·L -1 The highest purity of D-cystine is obtained when the concentration of hydrochloric acid is 0.08 mol·L -1 .
[0051] Embodiments 7 to 10
[0052] A high purity D-cystine
[0053] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0054] Wherein, the concentration of the hydrochloric acid is 0.08 mol·L -1 ; The concentration of the acetic acid is shown in Table 3;
[0055] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0056] The gradient hydrolysis is as follows: hydrolysis at 0°C for 10 min, hydrolysis at 20°C for 5 min, and hydrolysis at 30°C for 20 min;
[0057] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0058] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
[0059] Table 3 Concentration of acetic acid
[0060]
[0061] The purity of the high-purity D-cystine prepared in Examples 1 to 6 was tested, and the test results are shown in Table 4;
[0062] Table 4 Purity
[0063]
[0064] It can be seen from the data in Table 4 that the hydrolysis control method for preparing high-purity D-cystine provided by the present invention effectively improves the purity of the finally prepared D-cystine by adjusting the concentration of acetic acid in the mixed solution; moreover, as the concentration of acetic acid increases, the purity of D-cystine first increases and then decreases. When the concentration of acetic acid is 0.20 mol·L -1 The highest purity of D-cystine is obtained when the acetic acid concentration is 0.20 mol·L -1.
[0065] Comparative Example 1
[0066] A D-cystine
[0067] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water at a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding sulfuric acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution at a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to sulfuric acid of 20:3 to obtain a mixed solution;
[0068] Wherein, the concentration of the sulfuric acid is 0.10 mol·L -1 (Determination of sulfuric acid concentration: Detect the pH of the mixed solution obtained in Example 8, and then adjust the mixed solution to the same pH using sulfuric acid according to the detected pH);
[0069] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0070] The gradient hydrolysis is as follows: hydrolysis at 0°C for 10 min, hydrolysis at 20°C for 5 min, and hydrolysis at 30°C for 20 min;
[0071] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0072] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the D-cystine.
[0073] After testing, the purity of D-cystine obtained in Comparative Example 1 was 96.7%;
[0074] After analysis, the reason why the purity of D-cystine prepared in Comparative Example 1 decreases is that the hydrochloric acid and acetic acid added in the present invention can not only adjust the pH of the hydrolysis reaction system, but also promote the hydrolysis equilibrium of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to a greater extent in the positive reaction direction, while only adding sulfuric acid to change the pH of the hydrolysis reaction system cannot promote the hydrolysis in the positive reaction direction. Therefore, the present invention can effectively improve the purity of D-cystine by adding hydrochloric acid and acetic acid.
[0075] Embodiment 11
[0076] A high purity D-cystine
[0077] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0078] Wherein, the concentration of the hydrochloric acid is 0.08 mol·L -1 ; The concentration of the acetic acid is 0.20 mol·L -1 ;
[0079] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0080] The gradient hydrolysis is as follows: hydrolysis at 2°C for 10 min, hydrolysis at 23°C for 5 min, and hydrolysis at 32°C for 20 min;
[0081] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0082] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
[0083] Example 12
[0084] A high purity D-cystine
[0085] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0086] Wherein, the concentration of the hydrochloric acid is 0.08 mol·L -1 ; The concentration of the acetic acid is 0.20 mol·L -1 ;
[0087] 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine;
[0088] The gradient hydrolysis is as follows: hydrolysis at 4°C for 10 min, hydrolysis at 25°C for 5 min, and hydrolysis at 35°C for 20 min;
[0089] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0090] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
[0091] Comparative Example 2
[0092] A D-cystine
[0093] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0094] Wherein, the concentration of the hydrochloric acid is 0.08 mol·L -1 ; The concentration of the acetic acid is 0.20 mol·L -1 ;
[0095] 2) hydrolyzing the mixed solution obtained in step 1) at 35° C. for 30 min to obtain a hydrolyzate containing D-cysteine;
[0096] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0097] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the D-cystine.
[0098] Comparative Example 3
[0099] A D-cystine
[0100] 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water in a mass volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate to water of 1 g:20 mL to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution in a volume ratio of D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid of 20:1:2 to obtain a mixed solution;
[0101] Wherein, the concentration of the hydrochloric acid is 0.08 mol·L -1 ; The concentration of the acetic acid is 0.20 mol·L -1 ;
[0102] 2) hydrolyzing the mixed solution obtained in step 1) at 20° C. for 40 min to obtain a hydrolyzate containing D-cysteine;
[0103] 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5 with aqueous ammonia, standing for 60 minutes, filtering with suction, and retaining the filtrate;
[0104] 4) adding 20% by volume of hydrogen peroxide dropwise to the filtrate obtained in step 3) at a volume ratio of 15:1, standing for 30 minutes, filtering with suction, retaining the filter residue, and drying to obtain the D-cystine.
[0105] The purity of D-cystine prepared in Examples 11-12 and Comparative Examples 2-3 is shown in Table 5;
[0106] Table 5 Purity
[0107]
[0108]
[0109] It can be seen from the data in Table 5 that the hydrolysis control method for preparing high-purity D-cystine provided by the present invention effectively improves the purity of D-cystine by gradient hydrolysis and by adjusting the temperature and duration of hydrolysis.
[0110] 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 it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.
Claims
1. A hydrolysis control method for preparing high-purity D-cystine, characterized in that: The following steps are involved: 1) dissolving D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate in water to obtain a D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, and then adding hydrochloric acid and acetic acid to the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution to obtain a mixed solution; 2) performing gradient hydrolysis on the mixed solution obtained in step 1) to obtain a hydrolyzate containing D-cysteine; 3) adjusting the pH of the hydrolyzate containing D-cysteine obtained in step 2) to 5.5, allowing it to stand, filtering it with suction, and retaining the filtrate; 4) adding hydrogen peroxide dropwise to the filtrate obtained in step 3), allowing the mixture to stand, filtering with suction, retaining the filter residue, and drying to obtain the high-purity D-cystine.
2. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 1), the mass volume ratio of the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate and water is 1 g: 20 mL.
3. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 1), the concentration of hydrochloric acid is 0.05-0.10 mol·L -1 .
4. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 1), the concentration of acetic acid is 0.10-0.30 mol·L -1 .
5. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 1), the volume ratio of the D-2,2-dimethylthiazolidine-4-carboxylic acid-L-tartrate solution, hydrochloric acid and acetic acid is 20:1:
2.
6. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 2), the gradient hydrolysis is as follows: hydrolysis at 0-4°C for 10 min, hydrolysis at 20-25°C for 5 min, and hydrolysis at 30-35°C for 20 min.
7. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 3), the standing time is 60 minutes.
8. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 4), the volume fraction of the hydrogen peroxide is 20%.
9. A hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 4), the volume ratio of the filtrate to hydrogen peroxide is 15:
1.
10. The hydrolysis control method for preparing high-purity D-cystine according to claim 1, characterized in that: In step 4), the standing time is 30 minutes.