Preparation method of sodium 2-mercaptoethanesulfonate

Abstract

The invention discloses a preparation method of 2-mercaptoethanesulfonic acid sodium salt, which comprises the following steps: step 1, reacting halogenated ethanesulfonic acid sodium salt with thiourea to obtain thiourea salt (I) # imgabs 0 #; step 2, carrying out hydrolysis reaction on the thiourea salt (I) # imgabs 1 # in the presence of an alkaline substance to obtain 2-mercaptoethanesulfonic acid sodium salt; after the reaction is finished, a substance (II) imgabs2 # is obtained, then a reducing agent A is added for a reduction reaction, 2-mercaptoethanesulfonic acid sodium (III) imgabs3 # is obtained, R1 is-Br or-Cl, and the reducing agent A is zinc or magnesium. The preparation method adopts cheap and easily available raw materials, and is simple in reaction, high in safety, low in production cost and suitable for industrial production.

Description

Technical Field

[0001] The present application relates to the field of organic synthesis, and in particular to a method for preparing sodium 2-mercaptoethanesulfonate. Background Art

[0002] Sodium 2-mercaptoethanesulfonate (MESNA) is a multifunctional sulfur-containing compound containing a sulfhydryl group and a sulfonic acid group, and therefore has both reducing and hydrophilic properties. MESNA can be used as a chemotherapy adjuvant and mucolytic agent in the pharmaceutical industry, and has the effect of modifying proteins in the biochemical field, as well as surface modification in the synthesis of functional materials. Furthermore, MESNA has excellent water solubility and high safety. With the continuous development of the pharmaceutical industry and biochemical industry, its demand has also increased significantly, and its preparation method has therefore also attracted much attention.

[0003] Most of the methods for preparing sodium 2-mercaptoethanesulfonate reported in the prior art use 1,2-dichloroethane or 1,2-dibromoethane as the starting material, which is reacted with sodium sulfate to produce sodium 2-chloroethanesulfonate or sodium 2-bromoethanesulfonate, which is then reacted with thiourea and sodium hydroxide to produce sodium 2-mercaptoethanesulfonate. Due to the presence of disulfides and other impurities during this reaction, post-processing generally involves acidification followed by precipitation with lead acetate, pH adjustment to produce crude sodium 2-mercaptoethanesulfonate, and finally recrystallization to obtain pure sodium 2-mercaptoethanesulfonate, resulting in a relatively complex post-processing process.

[0004] For example, U.S. Patent No. 2005137419A1 discloses a preparation method that involves reacting sodium 2-bromoethylsulfonate with sodium hydroxide, thioacetic acid, and acetic acid to obtain the target product. In this method, the reaction of thioacetic acid with a strong base produces toxic sulfides and fumes, which not only reduces reaction safety and has a significant environmental impact, but also results in a low conversion rate.

[0005] Chinese patent CN107235873A discloses a preparation method that uses dimethoate as a raw material, Pd / C noble metal, and hydrogen as a catalyst under high-pressure hydrogenation conditions to obtain the target product. This method uses noble metals as catalysts and reacts under high pressure, resulting in low safety and high costs.

[0006] Therefore, it is particularly important to provide a method for preparing sodium 2-mercaptoethanesulfonate so as to overcome the shortcomings of the above-mentioned prior art. Summary of the Invention

[0007] In order to overcome the shortcomings of the above-mentioned prior art, the present application provides a method for preparing sodium 2-mercaptoethanesulfonate, the steps of which are as follows:

[0008] Step 1: reacting sodium haloethanesulfonate with thiourea to obtain thiourea salt (I);

[0009]

[0010] Step 2: hydrolyzing the thiourea salt (I) in the presence of an alkaline substance to obtain substance (II), and then adding a reducing agent A to react to obtain sodium 2-mercaptoethanesulfonate (III);

[0011]

[0012] Wherein, R1 is -Br or -Cl, and the reducing agent A is zinc or magnesium.

[0013] By adopting the above technical solution, compared with the preparation method of the prior art, the present application adopts cheap and readily available raw materials, and uses common alkaline substances and magnesium or zinc for reaction in the preparation method, does not use the reaction conditions of high-pressure hydrogenation, and does not use Pd / C precious metal for catalysis. Therefore, heavy metal lead and toxic sulfide and other substances are not introduced during the reaction process, thereby improving the safety of the reaction, reducing production costs, and almost no heavy metal lead is introduced when the drug is taken by the human body, which is safer. The technical solution of the present application abandons the relatively harsh reaction conditions and complex post-processing steps used in the prior art, making the reaction simpler and easier to operate, while improving the safety of the reaction. To a certain extent, it can represent a new trend in the preparation method of sodium 2-mercaptoethanesulfonate and is suitable for industrial production.

[0014] Furthermore, in step 1, the molar ratio of the sodium haloethanesulfonate to thiourea is 1:(1-2) mol;

[0015] In step 1, the reaction temperature is 60-100°C;

[0016] In step 1, the reaction time is 1 to 4 hours.

[0017] Furthermore, in step 2, the alkaline substance is selected from one or more of sodium hydroxide and ammonia water;

[0018] In step 2, the ratio of the thiourea salt (I) to the alkaline substance is 1 mol: (300-800) mL;

[0019] In step 2, the reaction temperature of the thiourea salt (I) in the presence of an alkaline substance is 40 to 80° C.;

[0020] In step 2, the reaction time of the thiourea salt (I) in the presence of an alkaline substance is 0.5 to 4 hours;

[0021] In step 2, the mass of the reducing agent A is 5% to 20% of the mass of the thiourea salt (I);

[0022] In step 2, while the substance (II) is reacting in the presence of a reducing agent A, an acidic substance is added dropwise, and the ratio of the thiourea salt (I) to the acidic substance is 1 mol: (100-300) mL;

[0023] In step 2, during the reaction of the substance (II) in the presence of a reducing agent A, the reaction temperature is 40 to 60°C;

[0024] In step 2, the substance (II) is reacted in the presence of a reducing agent A, and the reaction time is 1 to 5 hours.

[0025] By adopting the above technical solution and carrying out the reaction under the above-mentioned reaction conditions, sodium 2-mercaptoethanesulfonate with high purity and yield can be obtained. Compared with the existing technology, the reaction conditions are milder, the production cost can be greatly reduced, and it is suitable for industrial production.

[0026] In summary, this application has the following beneficial effects:

[0027] 1. The preparation method provided in this application does not use high-pressure hydrogenation reaction conditions, nor does it use Pd / C precious metal catalysis, which improves the safety of the reaction, reduces production costs, and almost no heavy metal lead is introduced when the drug is taken by the human body, making it safer.

[0028] 2. The preparation method provided in this application not only adopts relatively simple reaction conditions, but also achieves high purity and yield, and is suitable for industrial production. DETAILED DESCRIPTION

[0029] Example

[0030] The following example is a method for preparing sodium 2-mercaptoethanesulfonate.

[0031] Example 1

[0032] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 20 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 40.2 g of the thiourea salt. HPLC purity was 100%, and the yield was 97.5%.

[0033] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 13.2g of product, with a yield of 80.2%.

[0034] The mixture was further treated by adding 200 mL of methanol and beating for 2 h, filtering, and the filtrate was evaporated again under nitrogen to obtain 11.4 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 98.5%, the titratable content was 98.1%, and the pure product yield was 69.2%.

[0035] Example 2

[0036] Step 1: Weigh 42.2 g of sodium 2-bromoethylsulfonate and 15.2 g of thiourea, add 40 mL of water, and reflux at 100°C for 1 hour. After the reaction is complete, cool to room temperature. The product precipitates and is filtered. The filter cake is washed twice with water, and the solvent is drained to yield 39.6 g of the thiourea salt. HPLC purity is 100%, and the yield is 96.0%.

[0037] Step 2: Weigh 20.6 g of thiourea salt, add 50 mL of aqueous ammonia, and react at 65°C for 2 hours. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1 g of magnesium powder and slowly add 20 mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2 hours. After the reaction is complete, evaporate the solvent under nitrogen to obtain 12.7 g of product, with a yield of 77.2%.

[0038] The mixture was further treated by adding 200 mL of methanol for beating for 2 h, filtering, and the filtrate was again evaporated under nitrogen to obtain 10.2 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 97.6%, the titrated content was 96.3%, and the yield was 62.4%.

[0039] Example 3

[0040] Step 1: Weigh 50.0 g of sodium 2-chloroethylsulfonate and 22.8 g of thiourea, add 60 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 61.2 g of the thiourea salt. HPLC purity was 100%, and the yield was 99.0%.

[0041] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 40°C for 4 hours. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 1.0g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2 hours. After the reaction is completed, evaporate the solvent under nitrogen to obtain 11.7g of product, with a yield of 71.5%.

[0042] The mixture was further treated by adding 200 mL of methanol for 2 h of beating, filtering, and the filtrate was evaporated again under nitrogen to obtain 9.8 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 97.0%, the titratable content was 97.5%, and the yield was 59.8%.

[0043] Example 4

[0044] Step 1: Weigh 63.3 g of sodium 2-bromoethylsulfonate and 22.8 g of thiourea, add 60 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature. The product precipitates and is filtered. The filter cake is washed twice with water, and the solvent is drained to yield 60.0 g of the thiourea salt. HPLC purity is 100%, and the yield is 97.0%.

[0045] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 80°C for 0.5h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 4.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2h. After the reaction is complete, evaporate the solvent under nitrogen to obtain 12.1g of product, with a yield of 73.5%.

[0046] The mixture was further treated by adding 200 mL of methanol for beating for 2 h, filtering, and the filtrate was again evaporated under nitrogen to obtain 10.2 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 97.0%, the titratable content was 97.7%, and the yield was 62.1%.

[0047] Example 5

[0048] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 30.4 g of thiourea, add 40 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 40.6 g of the thiourea salt. HPLC purity was 100%, and the yield was 98.5%.

[0049] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 100°C for 0.5h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 10.2g of product, with a yield of 63.5%.

[0050] The mixture was further treated by adding 200 mL of methanol for beating for 2 h, filtering, and the filtrate was evaporated again under nitrogen to obtain 9.1 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 96.0%, the titratable content was 97.0%, and the yield was 55.3%.

[0051] Example 6

[0052] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 22.8 g of thiourea, add 40 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 41.0 g of the thiourea salt. HPLC purity was 100%, and the yield was 99.5%.

[0053] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 13.2g of product, with a yield of 80.2%.

[0054] The mixture was further treated by adding 200 mL of methanol for slurrying for 2 h, filtering, and the filtrate was again evaporated under nitrogen to obtain 11.4 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 98.4%, the titratable content was 98.1%, and the yield was 69.3%.

[0055] Example 7

[0056] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 40 mL of water, and reflux at 60°C for 4 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 39.9 g of the thiourea salt. HPLC purity was 100%, and the yield was 96.7%.

[0057] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 50°C for 1.5h. After the reaction is complete, evaporate the solvent under nitrogen to obtain 13.6g of product, with a yield of 82.9%.

[0058] The mixture was further treated by adding 200 mL of methanol for beating for 2 h, filtering, and the filtrate was evaporated again under nitrogen to obtain 11.5 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 98.1%, the titrated content was 97.5%, and the yield was 70.1%.

[0059] Example 8

[0060] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 40 mL of water, and reflux at 100°C for 1 hour. After the reaction is completed, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to obtain 39.7 g of the thiourea salt. HPLC purity was 100%, and the yield was 96.3%.

[0061] Step 2: Weigh 20.6g of thiourea salt, add 80mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 30mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 60°C for 1h. After the reaction is complete, evaporate the solvent under nitrogen to obtain 12.3g of product, with a yield of 75.2%.

[0062] The mixture was further treated by adding 200 mL of methanol for beating for 2 h, filtering, and the filtrate was evaporated again under nitrogen to obtain 10.4 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 97.0%, the titrated content was 96.7%, and the yield was 63.8%.

[0063] Example 9

[0064] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 20 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 40.2 g of the thiourea salt. HPLC purity was 100%, and the yield was 97.5%.

[0065] Step 2: Weigh 20.6g of thiourea salt, add 30mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 10mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 5h. After the reaction is complete, evaporate the solvent under nitrogen to obtain 12.1g of product, with a yield of 73.9%.

[0066] The mixture was further treated by adding 200 mL of methanol for 2 h of beating, filtering, and the filtrate was again evaporated under nitrogen to obtain 10.3 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 97.7%, the titratable content was 97.0%, and the yield was 62.7%.

[0067] Example 10

[0068] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 20 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 40.2 g of the thiourea salt. HPLC purity was 100%, and the yield was 97.5%.

[0069] Step 2: Weigh 20.6 g of thiourea salt, add 50 mL of 10% sodium hydroxide solution, and react at 65°C for 2 hours. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Continue adding 3.1 g of zinc powder, and slowly add 20 mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2 hours. After the reaction is completed, evaporate the solvent under nitrogen to obtain 11.6 g of product, with a yield of 71.0%.

[0070] The mixture was further treated by adding 200 mL of methanol and beating for 2 h, filtering, and the filtrate was evaporated again under nitrogen to obtain 9.6 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 95.2%, the titratable content was 95.1%, and the pure product yield was 58.3%.

[0071] Example 11

[0072] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 40 mL of water, and reflux at 50°C for 5 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 39.5 g of the thiourea salt. HPLC purity was 100%, and the yield was 95.7%.

[0073] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise under an ice bath. After the addition is complete, react at 30°C for 6h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 10.3g of product, with a yield of 63.0%.

[0074] Then 200 mL of methanol was added and the mixture was beaten for 2 h, filtered, and the filtrate was evaporated again under nitrogen to obtain 8.4 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 95.0%, the titrated content was 94.8%, and the yield was 51.2%.

[0075] Example 12

[0076] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 40 mL of water, and reflux at 120°C for 0.5 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 34.6 g of the thiourea salt. HPLC purity was 97%, and the yield was 83.9%.

[0077] Step 2: Weigh 20.6g of thiourea salt, add 100mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 3.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 80°C for 0.5h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 10.3g of product, with a yield of 62.6%.

[0078] Then 200 mL of methanol was added and the mixture was beaten for 2 h, filtered, and the filtrate was evaporated again under nitrogen to obtain 8.2 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 93.0%, the titrated content was 91.4%, and the yield was 50.1%.

[0079] Example 13

[0080] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 38.0 g of thiourea, add 40 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 20.7 g of the thiourea salt. HPLC purity was 99.3%, and the yield was 97.6%.

[0081] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 5.1g of magnesium powder and slowly add 20mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2h. After the reaction is complete, evaporate the solvent under nitrogen to obtain 11.2g of product, with a yield of 68.3%.

[0082] The mixture was further treated by adding 200 mL of methanol and beating for 2 h, filtering, and the filtrate was again evaporated under nitrogen to obtain 9.5 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 97%, the titratable content was 96.3%, and the pure product yield was 57.7%.

[0083] Example 14

[0084] Step 1: Weigh 33.2 g of sodium 2-chloroethylsulfonate and 15.2 g of thiourea, add 20 mL of water, and reflux at 100°C for 2 h. After the reaction is complete, cool to room temperature, filter the precipitated product, and wash the filter cake twice with water. Drain the solvent to yield 40.2 g of the thiourea salt. HPLC purity was 100%, and the yield was 97.5%.

[0085] Step 2: Weigh 20.6g of thiourea salt, add 50mL of 10% sodium hydroxide solution, and react at 65°C for 2h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 0.4g of magnesium powder and slowly add 40mL of glacial acetic acid dropwise in an ice bath. After the addition is complete, react at 40°C for 2h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 9.3g of product, with a yield of 56.7%.

[0086] The mixture was further treated by adding 200 mL of methanol and beating for 2 h, filtering, and the filtrate was again evaporated under nitrogen to obtain 7.6 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 95.0%, the titratable content was 94.0%, and the pure product yield was 46.3%.

[0087] Comparative Example 1

[0088] Weigh 20.6 g of the thiourea salt obtained in step 1 of Example 3, add 50 mL of 10% sodium hydroxide solution, and react at 65°C for 2 h. After the reaction is complete, adjust the pH to 6-7 with glacial acetic acid to obtain a reaction solution. Add 2.8 g of tris(2-carboxyethyl)phosphine (TCEP), and react at 40°C for 2 h. After the reaction is completed, evaporate the solvent under nitrogen to obtain 5.7 g of the product, with a yield of 34.6%.

[0089] The mixture was further treated by adding 200 mL of methanol and beating for 2 h, filtering, and the filtrate was evaporated again under nitrogen to obtain 3.1 g of sodium 2-mercaptoethanesulfonate. After testing, the HPLC purity was 93.0%, the titratable content was 92.7%, and the pure product yield was 19.1%.

[0090] It is worth noting that the present application is not limited to the use of zinc powder or magnesium powder, and other shapes such as zinc bars, zinc rods, zinc sheets, magnesium bars, magnesium rods, and magnesium sheets can also be used for the reaction.

[0091] By comparing the above Examples 1 to 14 and Comparative Example 1, it can be seen that when the preparation method of the present application is used, especially when zinc powder and magnesium powder are used as reducing agents to participate in the reaction, the reaction effect obtained is far better than the conventional disulfide bond reducing agents used in the prior art, and the yield and purity are greatly improved. In addition, from the perspective of titration content, the salt content of sodium 2-mercaptoethanesulfonate obtained by the preparation method of the present application is extremely low, and the obtained product has higher purity, meeting higher usage requirements.

[0092] Furthermore, the above examples show that the present invention utilizes inexpensive and readily available raw materials, does not employ high-pressure hydrogenation reaction conditions, and does not utilize Pd / C noble metal catalysis. This results in a highly safe reaction with low production costs. Furthermore, after completion of the reaction, a relatively high yield and high purity are achieved. Furthermore, titration of the content reveals that the sodium 2-mercaptoethanesulfonate obtained in the present invention is salt-free and highly pure. Furthermore, the present invention also includes a relatively simple post-processing step, is easy to operate, and is suitable for industrial production.

[0093] The above specific embodiments are merely explanations of the present application and are not limitations of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the above embodiments as needed, but as long as they are within the scope of the claims of the present application, they are protected by patent law.

Claims

1. A method for preparing sodium 2-mercaptoethanesulfonate, characterized in that: Here are the steps: Step 1: reacting sodium haloethanesulfonate with thiourea to obtain thiourea salt (I); Step 2: hydrolyzing the thiourea salt (I) in the presence of an alkaline substance to obtain substance (II), and then adding a reducing agent A to react to obtain sodium 2-mercaptoethanesulfonate (III); Wherein, R1 is -Br or -Cl, and the reducing agent A is zinc or magnesium.

2. The preparation method according to claim 1, characterized in that In step 1, the molar ratio of the sodium haloethanesulfonate to thiourea is 1:(1-2).

3. The preparation method according to claim 1 or 2, characterized in that In step 1, the reaction temperature is 60-100°C; Preferably, in step 1, the reaction time is 1 to 4 hours.

4. The preparation method according to claim 1 or 2, characterized in that In step 2, the alkaline substance is selected from one or more of sodium hydroxide and ammonia water.

5. The preparation method according to claim 1 or 2, characterized in that In step 2, the ratio of the thiourea salt (I) to the alkaline substance is 1 mol: (300-800) mL.

6. The preparation method according to claim 1, characterized in that In step 2, the reaction temperature of the thiourea salt (I) in the presence of an alkaline substance is 40-80°C.

7. The preparation method according to claim 1, characterized in that In step 2, the reaction time of the thiourea salt (I) in the presence of an alkaline substance is 0.5 to 4 hours.

8. The preparation method according to claim 1, characterized in that In step 2, the mass of the reducing agent A is 5% to 20% of the mass of the thiourea salt (I).

9. The preparation method according to claim 1, characterized in that In step 2, while the substance (II) is reacting in the presence of a reducing agent A, an acidic substance is added dropwise. The ratio of the thiourea salt (I) to the acidic substance is 1 mol: (100-300) mL.

10. The preparation method according to claim 1, characterized in that In step 2, during the reaction of the substance (II) in the presence of a reducing agent A, the reaction temperature is 40 to 60°C; Preferably, in step 2, during the reaction of the substance (II) in the presence of the reducing agent A, the reaction time is 1 to 5 hours.

Images