A method for purifying sodium 3-thiopropanesulfonate

Abstract

The invention belongs to the technical field of preparation of sodium 3-mercaptopropanesulfonate, and in particular to a method for purifying sodium 3-mercaptopropanesulfonate. The method comprises the following steps: S1 adds inorganic alkali solution to 3-mercaptopropanesulfonate solution, adjusts pH to 6-8, and then adds thioethanol to mix and a reduction reaction occurs; S2 waits for the reaction to pass the reaction solution through a cation exchange resin, adjusts the pH value of the obtained resin exchange liquid to 2-5, and is concentrated to a solution where a white solid precipitates, adds a mixed solvent of methanol and ethanol to dissolve the concentrate, and finally adopts gradient cooling crystallization; S3 is centrifuged, separated, and pure sodium 3-mercaptopropanesulfonate is obtained after the solid is dried. The purity of sodium 3-mercaptopropanesulfonate after purification by the inventive method reaches more than 96%, and the yield reaches more than 90%.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of sodium 3-mercaptopropanesulfonate, and particularly relates to a method for purifying sodium 3-mercaptopropanesulfonate. Background Art

[0002] Sodium mercaptodipropane sulfonate (MPS) is a widely used copper plating brightener in printed circuit board (PCB) and acid copper plating. It can also be used as a pharmaceutical intermediate. Currently, MPS is primarily produced domestically and internationally using 1,3-propane sultone and sodium sulfide. This production process yields only approximately 80-90% effective content and contains significant amounts of polysulfide impurities. This fails to meet the purity requirements of downstream applications, including pharmaceuticals and electroplating. Therefore, a method for purifying sodium 3-mercaptopropane sulfonate is urgently needed in this field. Summary of the Invention

[0003] In order to overcome the above problems in the prior art, the object of the present invention is to provide a method for purifying sodium 3-thiopropanesulfonate.

[0004] In order to achieve the above-mentioned object of the invention, one of the technical solutions of the present invention is:

[0005] A method for purifying sodium 3-thiopropanesulfonate comprises the following steps:

[0006] S1 Add inorganic alkali solution to the sodium 3-thiopropanesulfonate solution to adjust the pH to 6-8, then add thioethanol and mix to cause reduction reaction

[0007] S2 After the reaction is completed, the reaction solution is passed through a cation exchange resin, the pH value of the obtained resin exchange solution is adjusted to 2-5, and the solution is concentrated until a white solid precipitates, and a methanol / ethanol mixed solvent is added to dissolve the concentrate, and finally a gradient cooling crystallization is performed;

[0008] S3 is centrifuged and the solid is dried to obtain pure sodium 3-thiopropanesulfonate.

[0009] Preferably, the drying temperature in step S3 is 30-70° C., and the drying time is 1-3 hours.

[0010] Preferably, the concentration temperature is 60-85°C.

[0011] The volume ratio of methanol to ethanol in the methanol / ethanol mixed solvent is 10-50:10-50.

[0012] Preferably, the temperature of the reduction reaction is 10-60°C; more preferably 40-60°C.

[0013] Preferably, the reaction time of the reduction reaction is 1-12 h; more preferably 1-4 h.

[0014] Preferably, the cationic resin is a weak acid resin with carboxylic acid group - COOH, phosphoric acid group - PO2H2, or phenol group. For example, it can be D113 macroporous weak acid acrylic cation exchange resin CAS: 130353-60-5, weak acid cation exchange resin methacrylic acid type - DIAION WK10 or aminophosphoric acid resin LSC-500 macroporous styrene-divinylbenzene copolymer with weak acid aminophosphonic acid (-CH2NHCH2PO3 - ) chelating resin.

[0015] Preferably, the sodium 3-mercaptopropanesulfonate solution in step S1 is an aqueous solution of sodium 3-mercaptopropanesulfonate, which is prepared from sodium 3-mercaptopropanesulfonate and water in a weight ratio of 100 parts:50-200 parts.

[0016] Preferably, the weight ratio of mercaptoethanol to sodium 3-mercaptopropanesulfonate is 1-20:100.

[0017] More preferably, the weight ratio of thioethanol to sodium 3-thiopropanesulfonate is 10-20:100.

[0018] Preferably, the amount of the cationic resin used is 1-3 times that of sodium 3-mercaptopropanesulfonate.

[0019] Preferably, the inorganic base is sodium carbonate and / or sodium bicarbonate.

[0020] Preferably, the procedure of gradient cooling is: firstly quickly cool down to 50-60°C, and then cool down to below 25°C at 6-8°C per hour.

[0021] Beneficial effects

[0022] Compared with the prior art, the present invention has the following advantages:

[0023] The purity of the sodium 3-thiopropanesulfonate purified by the method of the invention can be as high as over 96%, and the yield can reach over 90%. DETAILED DESCRIPTION

[0024] The method of the present invention is described below by means of specific examples to make the technical solution of the present invention easier to understand and grasp, but the present invention is not limited thereto. The experimental methods described in the following examples are conventional methods unless otherwise specified; the reagents and materials described are all commercially available unless otherwise specified.

[0025] Example 1

[0026] A method for purifying sodium 3-thiopropanesulfonate comprises the following steps:

[0027] S1: Sodium carbonate was added to a solution of sodium 3-mercaptopropanesulfonate (an aqueous solution prepared by 100 parts of sodium 3-mercaptopropanesulfonate and 200 parts of pure water) to adjust the pH to 6.5-7, and 10 parts of thioethanol was added and mixed, and the mixture was reacted at 40°C for 2 hours;

[0028] After the reaction is completed, the reaction solution is passed through a cation exchange resin (D113 macroporous weakly acidic acrylic cation exchange resin, CAS: 130353-60-5). Sodium carbonate is added to adjust the pH value of the resin exchange solution to 3. The solution is concentrated at 80°C to remove water until a white solid precipitates. A mixed solvent of methanol and ethanol (methanol:ethanol = 50 parts:50 parts) is added to dissolve the concentrate. Finally, a gradient cooling process is used for crystallization. The gradient cooling process is as follows: first, the temperature is rapidly cooled from 80°C to 60°C, and then the temperature is cooled at a rate of 8°C per hour to below 25°C.

[0029] S3: The sample crystallized in step S2 is centrifuged at 20° C., and the obtained powder is dried at 30-40° C. for 2 h to obtain pure sodium 3-thiopropanesulfonate.

[0030] The following content tests were performed on the pure sodium 3-thiopropanesulfonate:

[0031] The obtained sample of sodium 3-thiopropanesulfonate was prepared into a 10% aqueous solution, starch indicator was added thereto, 1 mL of 32% hydrochloric acid was added thereto, and titration was performed with iodine solution. The solution stopped when it turned from colorless to light blue.

[0032] After testing, the purity of the pure sodium 3-thiopropanesulfonate obtained in this example was 95.6%, and the yield was 93.9%.

[0033] Example 2

[0034] A method for purifying sodium 3-mercaptopropanesulfonate is provided, which differs from Example 1 only in that 2 parts of mercaptoethanol are added.

[0035] After testing, the purity of the pure sodium 3-thiopropanesulfonate obtained in this example was 90.1%, and the yield was 90.2%.

[0036] Example 3

[0037] A method for purifying sodium 3-thiopropanesulfonate, which differs from Example 1 only in that:

[0038] The S2 operation is as follows:

[0039] After the reaction is completed, the reaction solution is passed through a cation exchange resin (D113 macroporous weakly acidic acrylic cation exchange resin CAS: 130353-60-5), and sodium carbonate is added to adjust the pH value of the resulting resin exchange solution to 3. The water is concentrated at 80°C to remove the water until a white solid precipitates from the solution. 50 parts of methanol are added to dissolve the concentrate, and finally, gradient cooling crystallization is performed; the gradient cooling program is as follows: first, the temperature is rapidly reduced from 80°C to 60°C, and then the temperature is reduced at 20°C per hour to below 25°C.

[0040] After testing, the purity of the pure sodium 3-thiopropanesulfonate obtained in this example was 88.9%, and the yield was 86.7%.

[0041] Example 4

[0042] A method for purifying sodium 3-thiopropanesulfonate, which differs from Example 1 only in that:

[0043] S1: Sodium carbonate was added to a sodium 3-mercaptopropanesulfonate solution (an aqueous solution prepared by 100 parts of sodium 3-mercaptopropanesulfonate and 50 parts of pure water) to adjust the pH to 6.5-7, and 10 parts of thioethanol was added and mixed, and the mixture was reacted at 40°C for 2 hours.

[0044] After testing, the purity of the pure sodium 3-thiopropanesulfonate obtained in this example was 92.3%, and the yield was 90.5%.

[0045] Example 5

[0046] A method for purifying sodium 3-thiopropanesulfonate, which differs from Example 1 only in that:

[0047] S1: Sodium carbonate was added to a sodium 3-mercaptopropanesulfonate solution (an aqueous solution prepared by 100 parts of sodium 3-mercaptopropanesulfonate and 200 parts of pure water) to adjust the pH to 6.5-7, and 10 parts of thioethanol was added and mixed, and the mixture was reacted at 0°C for 2 hours.

[0048] After testing, the purity of the pure sodium 3-thiopropanesulfonate obtained in this example was 83.9%, and the yield was 80.3%.

[0049] Example 6

[0050] A method for purifying sodium 3-thiopropanesulfonate, which differs from Example 1 only in that:

[0051] S1: Sodium carbonate was added to a sodium 3-mercaptopropanesulfonate solution (an aqueous solution prepared by 100 parts of sodium 3-mercaptopropanesulfonate and 200 parts of pure water) to adjust the pH to 6.5-7, and 10 parts of thioethanol was added and mixed, and the mixture was reacted at 40°C for 4 hours.

[0052] After testing, the purity of the pure sodium 3-thiopropanesulfonate obtained in this example was 97.8%, and the yield was 93.3%.

[0053] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, rather than to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by ordinary technicians in this field do not deviate from the essence and scope of the technical solution of the present invention.

Claims

1. A method for purifying sodium 3-thiopropanesulfonate, comprising the steps of: S1: adding inorganic alkali solution to the sodium 3-mercaptopropanesulfonate solution to adjust the pH to 6-8, then adding thioethanol and mixing to cause a reduction reaction; After the reaction is completed, the reaction solution is passed through a cation exchange resin, the pH value of the resin exchange solution is adjusted to 2-5, and the solution is concentrated until a white solid precipitates. A mixed solvent of methanol and ethanol is added to dissolve the concentrate, and finally a gradient cooling crystallization is performed; S3 is centrifuged and separated, and the solid is dried to obtain pure sodium 3-thiopropanesulfonate.

2. The method for purifying sodium 3-mercaptopropanesulfonate according to claim 1, wherein the sodium 3-mercaptopropanesulfonate solution in step S1 is an aqueous solution of sodium 3-mercaptopropanesulfonate, which is prepared by mixing sodium 3-mercaptopropanesulfonate with water in a weight ratio of 100 parts:50-200 parts.

3. The method for purifying sodium 3-mercaptopropanesulfonate according to claim 1, wherein the weight ratio of mercaptoethanol to sodium 3-mercaptopropanesulfonate is 1-20:

100.

4. The method for purifying sodium 3-sulfanylpropanesulfonate according to claim 1, wherein the inorganic base is sodium carbonate and / or sodium bicarbonate.

5. The method for purifying sodium 3-mercaptopropanesulfonate according to claim 1, wherein the gradient cooling procedure is: first, rapidly cooling to 50-60°C, and then cooling to below 25°C at a rate of 6-8°C per hour.

6. The method for purifying sodium 3-mercaptopropanesulfonate according to claim 1, wherein the temperature during concentration in step S2 is 60-85°C.

7. The method for purifying sodium 3-mercaptopropanesulfonate according to claim 1, wherein the reaction temperature of the reduction reaction in step S1 is 10-60°C.

8. The method for purifying sodium 3-mercaptopropanesulfonate according to claim 1, wherein the reaction time of the reduction reaction in step S1 is 1-12 hours.