A method for synthesizing 4,4'-oxybis(benzenesulfonyl hydrazide)

Abstract

The present invention discloses a method for synthesizing 4,4'-oxybisbenzenesulfonyl hydrazide, which comprises the following steps: adding diphenyl ether dropwise into a mixed solution of halogenated sulfonic acid and an organic solvent, and after the dropping is completed, adding an alkali metal salt for heat preservation reaction. After the heat preservation reaction, water is added dropwise to decompose the excessive chlorosulfonic acid, and the intermediate solution is obtained by liquid separation. Then the intermediate solution is washed with alkali, and then the intermediate solution is added dropwise into a mixed solution of hydrazine hydrate and ammonia water. After heat preservation, post-treatment is carried out to obtain the product. The present invention omits the steps of intermediate distillation, filtration and water washing for purification, saves the reaction process and energy consumption, and has less generation of three wastes; at the same time, by optimizing the synthesis steps, the finally obtained product has high purity, high molar yield and stable product quality.

Description

Technical Field

[0001] The present invention relates to a method for synthesizing 4,4'-oxybis(benzenesulfonylhydrazide), and particularly to a method for synthesizing 4,4'-oxybis(benzenesulfonylhydrazide) with simple operation and without the need to extract intermediates, belonging to the technical field of organic fine chemicals. Background Art

[0002] 4,4-Oxybis(benzenesulfonylhydrazide) (OBSH) blowing agent is the most important sulfonylhydrazide blowing agent. Due to its moderate decomposition temperature, uniform pore structure, it can decompose into non-toxic nitrogen and water, and the residue does not affect electrical insulation. It is widely used in materials such as rubber, plastics, and polyurethane, especially having significant advantages in wire and cable materials, and is called a universal blowing agent. Traditional rubber products such as PE foamed floor mats and sealing rubber strips are foamed by using blowing agent AC to decompose and generate gas. The decomposition products of AC will produce harmful substance formamide. And formamide is a toxic substance, slightly irritating to the human skin, easy to cause allergies, and harmful to the human body. The limit value of formamide formulated by the European Union in October 2015 is ≤200 mg / kg. There is no corresponding national standard in China for the time being, but using the environmentally friendly blowing agent OBSH to replace the non-environmentally friendly traditional blowing agent AC is the current trend in the blowing agent industry.

[0003] CN106588703A proposed a method for 4,4-oxybis(benzenesulfonylhydrazide) (OBSH) intermediate 4,4-oxybis(benzenesulfonyl chloride) (intermediate), using concentrated sulfuric acid and diphenyl ether for sulfonation reaction, and then using easily decomposable phosphorus oxychloride for chlorination to obtain the intermediate. The reaction process requires negative pressure distillation to remove water, and the reaction conditions are harsh.

[0004] CN104072393A proposed a method for 4,4-oxybis(benzenesulfonyl chloride) (intermediate), prepared by introducing chlorine gas and sulfur dioxide gas into diphenyl ether for chlorination and sulfonation reactions. The reaction steps are complex and difficult to industrialize.

[0005] CN114436907A proposed a method for preparing OBSH from the intermediate, mixing the intermediate with water and then dropping it into hydrazine hydrate. Since the intermediate is insoluble in water, it is extremely easy to block the pipeline during the dropping process, resulting in difficult control of the dropping speed and large differences between reaction batches.

[0006] Currently, the research on OBSH mostly focuses on the synthesis of intermediates. There is less research on directly synthesizing OBSH from raw materials such as diphenyl ether. The related research has disadvantages such as harsh reaction conditions, unsuitability for industrialization, and difficult treatment of three wastes. Moreover, there are many by-products in the intermediate synthesis process, the yield is low, and the synthesized intermediate needs to be extracted by operations such as distillation, filtration, and water washing, and then used for synthesizing OBSH, with cumbersome operations. Summary of the Invention

[0007] In view of the deficiencies in the existing methods for synthesizing 4,4'-oxybis(benzenesulfonyl hydrazide), the present invention provides a method for synthesizing 4,4'-oxybis(benzenesulfonyl hydrazide). This method does not require the separation and purification of intermediates before the next operation, saving the production process, reducing the consumption of three wastes, and being more suitable for industrial production.

[0008] The specific technical solution of the present invention is as follows:

[0009] A method for synthesizing 4,4'-oxybis(benzenesulfonyl hydrazide), which comprises the following steps:

[0010] (1) Drop diphenyl ether into a mixed solution of halogenated sulfonic acid and organic solvent. After dropping, add alkali metal salt, and then keep the temperature for reaction;

[0011] (2) After the reaction, add water to the reaction solution to decompose the excessive halogenated sulfonic acid, and then separate the organic phase by liquid separation to obtain an intermediate solution;

[0012] (3) Wash the intermediate solution with alkali, and then drop the alkali-washed intermediate solution into a mixed solution of hydrazine hydrate and ammonia water. After dropping, keep the temperature for reaction, and perform post-treatment after the reaction to obtain 4,4'-oxybis(benzenesulfonyl hydrazide).

[0013] In the present invention, diphenyl ether and chlorosulfonic acid first undergo sulfonation and then chlorination reaction to obtain an intermediate, and then the intermediate reacts with hydrazine hydrate and ammonia water to obtain the final product. The reaction formula is as follows:

[0014]

[0015] Furthermore, in the above step (1), the halogenated sulfonic acid can be chlorosulfonic acid, fluorosulfonic acid, etc. The molar ratio of diphenyl ether to chlorosulfonic acid is 1:4 to 1:8, such as 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8. To make the reaction of diphenyl ether complete and reduce the amount of wastewater generated, the preferred molar ratio is 1:4 to 1:5.

[0016] Furthermore, in the above step (1), the dropping time of diphenyl ether is 2 to 6 h, such as 2 h, 3 h, 4 h, 5 h, 6 h. The dropping temperature of diphenyl ether is 20 to 40 °C, such as 20 °C, 30 °C, 40 °C. In the present invention, dropping diphenyl ether into the mixture of halogenated sulfonic acid and organic solvent can better reduce the generation of side reactions and improve the yield.

[0017] Furthermore, in the above step (1), the organic solvent is at least one of dichloromethane, dichloroethane, DMSO (dimethyl sulfoxide).

[0018] Further, in the above step (1), the molar ratio of the organic solvent to diphenyl ether is 5-10:1, such as 5:1, 6:1, 7:1, 8:1, 9:1, 10:1.

[0019] Further, in the above step (1), after dropping diphenyl ether, an alkali metal salt is added to consume the by-product concentrated sulfuric acid generated by the chlorination reaction, so that the reaction proceeds to the right, improving the reaction efficiency and reaction yield.

[0020] Further, in the above step (1), the alkali metal salt is sodium chloride, sodium sulfate, potassium chloride, etc. The molar ratio of the alkali metal salt to diphenyl ether is 0.1-1:1, such as 0.1:1, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1.0:1.

[0021] Further, in the above step (1), after dropping diphenyl ether and adding the alkali metal salt, the reaction is continued at 20-40 °C for 1-4 h.

[0022] Further, in the above step (2), after the reaction, water is dropped to hydrolyze the excess halogenated sulfonic acid. The amount of water used is for the purpose of removing the excess halogenated sulfonic acid. Generally, the molar ratio of the dropped water to diphenyl ether is 1:1-10, such as 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10. The temperature of the dropped water is not higher than room temperature, preferably 0-5 °C, which can effectively prevent runaway temperature during the hydrolysis of halogenated sulfonic acid.

[0023] Further, in the above step (3), the intermediate solution is washed with an alkali solution until the pH of the intermediate solution is 6-7. After alkali washing, liquid separation can be carried out to remove the aqueous phase. The alkali solution is sodium hydroxide solution or potassium hydroxide solution, and the concentration of the alkali solution is 5-10 w%.

[0024] Further, in the above step (3), the molar ratio of the intermediate: hydrazine hydrate: ammonia in ammonia water is 1:2-2.2:1-2.5.

[0025] Further, in the above step (3), both ammonia water and hydrazine hydrate are added in the form of solutions. The concentration of the ammonia water is 25-28 wt%, and the concentration of the hydrazine hydrate is 80-85 wt%.

[0026] Further, in the above step (3), the dropping temperature of the intermediate solution after alkali washing is 20-40 °C, and the dropping time is 1-4 h.

[0027] Further, in the above step (3), after dropping, the reaction is continued to be kept warm at 20-40 °C for 0.5-2 h.

[0028] Further, in the above step (3), after the heat preservation reaction is completed, the reaction material is cooled to 0-8°C for crystallization, and then the obtained crystals are filtered and dried to obtain 4,4'-oxybisbenzenesulfonylhydrazide. Grinding and sieving 4,4'-oxybisbenzenesulfonylhydrazide can obtain 4,4'-oxybisbenzenesulfonylhydrazide with different particle sizes.

[0029] The present invention has the following beneficial effects:

[0030] (1) By adjusting the feeding order of raw materials, adding alkali metal salts during the preparation of intermediates to remove by-products, adding water after the reaction to remove halogenated sulfonic acid, and alkali washing the intermediate solution, etc., the present invention improves the yield and purity of the intermediate, enabling the intermediate to directly react with hydrazine hydrate to form 4,4'-oxybisbenzenesulfonylhydrazide without purification and separation after alkali washing, saving reaction procedures and energy consumption, and reducing the amount of three wastes.

[0031] (2) The present invention drops diphenyl ether into halogenated sulfonic acid, making the halogenated sulfonic acid in an excessive state at the beginning of the reaction to promote the reaction. At the same time, the reaction process is controlled by the dropping rate to reduce the generation of side reactions. Moreover, dropping diphenyl ether instead of highly corrosive halogenated sulfonic acid can effectively prevent the raw material from corroding the dropping pipeline.

[0032] (3) By adding an appropriate amount of alkali metal salt during the heat preservation stage after dropping diphenyl ether, the present invention can continuously consume the by-product concentrated sulfuric acid generated during the chlorination stage, promote the forward reaction, and make the yield of the intermediate reach up to more than 95%.

[0033] (4) By adopting the reaction method of dropping the intermediate solution into hydrazine hydrate, the present invention can effectively control the particle size of the OBSH generated by the reaction. After filtration, washing, and drying, it is convenient to process into finished products with different particle sizes through grinding and sieving, and the product quality is more stable. Specific embodiments

[0034] The following further illustrates the present invention through specific examples. The following description is only exemplary and does not limit its content.

[0035] Unless otherwise specified, the following concentrations are all mass percentages.

[0036] Example 1

[0037] (1) Mix 200 g of chlorosulfonic acid with 280 g of dichloromethane and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction materials at a temperature of 30 °C, and control the dropping rate to drop 60 g of diphenyl ether within 2 h. The tail gas generated during the dropping and reaction process is cooled with 0 - 5 °C cold brine and then absorbed with sodium hydroxide solution. After the dropping is completed, add 5 g of sodium chloride, and keep the materials at 30 °C for a reaction for 2 h. After the heat preservation reaction is completed, drop 50 g of water to decompose the excessive chlorosulfonic acid, and at the same time extract the concentrated sulfuric acid generated by the reaction into the water. Separate the liquid to obtain the upper intermediate - dichloromethane solution. Wash the intermediate - dichloromethane solution with a sodium hydroxide solution with a concentration of 5 - 10 wt% until the pH is 6 - 7. After alkali washing, separate the liquid and take the organic phase to obtain the intermediate - dichloromethane solution after alkali washing.

[0038] (2) Mix 43 g of hydrazine hydrate (concentration 85%) with 50 g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction materials at a temperature of 30 °C, and drop the intermediate - dichloromethane solution after alkali washing in step (1) into the flask, and the dropping time is 1 h. The tail gas generated during the dropping and reaction process is cooled with 0 - 5 °C cold brine and then absorbed with hydrochloric acid solution. After the dropping is completed, keep the materials at 30 °C for a reaction for 1 h. After the heat preservation reaction is completed, gradually cool the materials to 5 °C to precipitate OBSH. Filter OBSH and dry it.

[0039] (3) Grind the dry OBSH product and sieve it through a 1000 - mesh sieve to obtain an OBSH finished product with a median particle size of about 10 μm. Detect the purity of the finished product and calculate the yield based on diphenyl ether as the substrate.

[0040] The purity of OBSH is detected according to the purity detection method in Q / KY002 - 2023 "Industrial 4,4'-oxybisbenzenesulfonylhydrazide (OBSH foaming agent)". The theoretical mass m0 of 100% conversion of diphenyl ether to OBSH = 126.327 g, then the yield calculation formula of OBSH is yield = , where m is the actual mass of OBSH and c is the purity of OBSH.

[0041] The detected purity of OBSH is 98.8%, and the yield of OBSH calculated based on diphenyl ether is 95.3%.

[0042] Example 2

[0043] (1) Mix 200 g of chlorosulfonic acid with 280 g of dichloromethane and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction material to be kept at 30 °C, and control the dropping rate to drop 60 g of diphenyl ether within 2 h. The tail gas generated during the dropping and reaction process is cooled with 0-5 °C cold brine and then absorbed with sodium hydroxide solution. After the dropping is completed, add 5 g of sodium chloride, and keep the material reacting at 30 °C for 2 h. After the heat preservation reaction is completed, drop 50 g of water to decompose the excessive chlorosulfonic acid, and at the same time extract the concentrated sulfuric acid generated by the reaction into the water. Separate the liquid to obtain the upper intermediate - dichloromethane solution. Add 50 g of water to prevent drying to dryness, and distill the material in a rotary evaporator at 60 °C until no distillate is produced. After washing and drying the obtained white solid particles, the intermediate is obtained. The purity of the intermediate is detected according to the purity detection method in Q / KY001-2023 "Industrial 4,4'-oxybisbenzenesulfonyl chloride (intermediate)". The yield calculation formula of the intermediate is: Yield = Intermediate mass * Intermediate purity / (Molar amount of diphenyl ether * Molecular weight of intermediate) * 100%. The measured purity of the intermediate is 98.8%, and the calculated yield of the intermediate is 96.2%.

[0044] (2) Mix 43 g of hydrazine hydrate (concentration 85%) with 50 g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction material to be kept at 30 °C, dissolve the intermediate obtained in step (1) in 280 g of dichloromethane, and drop the intermediate-dichloromethane solution into the flask, and the dropping time is 1 h. The tail gas generated during the dropping and reaction process is cooled with 0-5 °C cold brine and then absorbed with hydrochloric acid solution. After the dropping is completed, keep the material reacting at 30 °C for 1 h. After the heat preservation reaction is completed, gradually cool the material to 5 °C to precipitate OBSH. Filter OBSH and dry it.

[0045] (3) Grind the dry OBSH product and sieve it through a 1000-mesh sieve to obtain an OBSH finished product with a median particle size of about 10 μm.

[0046] The measured purity of OBSH is 98.5%, and the yield of OBSH calculated based on diphenyl ether is 95.1%.

[0047] Example 3

[0048] (1) Mix 328 g of chlorosulfonic acid with 260 g of DMSO and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction material to be kept at 30°C, and control the dropping rate to drop 60 g of diphenyl ether within 2 h. The tail gas generated during the dropping and reaction processes is cooled with 0-5°C cold brine and then absorbed with sodium hydroxide solution. After the dropping is completed, add 5 g of sodium chloride, and keep the material at 30°C for a reaction for 2 h. After the holding reaction is completed, drop 300 g of water to decompose the excessive chlorosulfonic acid, generating a large amount of hydrochloric acid gas. At the same time, extract the concentrated sulfuric acid generated by the reaction into the water. Separate the liquid to obtain the upper intermediate - dichloromethane solution. Wash the intermediate - DMSO solution with a sodium hydroxide solution with a concentration of 5-10 wt% until the pH is 6-7. After alkali washing, separate the liquid to take the organic phase to obtain the alkali-washed intermediate - dichloromethane solution.

[0049] (2) Mix 43 g of hydrazine hydrate (concentration 85%) with 50 g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction material to be kept at 30°C, and drop the alkali-washed intermediate - dichloromethane solution in step (1) into the flask. The dropping time is 1 h. The tail gas generated during the dropping and reaction processes is cooled with 0-5°C cold brine and then absorbed with hydrochloric acid solution. After the dropping is completed, keep the material at 30°C for a reaction for 1 h. After the holding reaction is completed, gradually cool the material to 5°C to precipitate OBSH. Filter OBSH and dry it.

[0050] (3) Grind the dry OBSH product and sieve it through a 1000-mesh sieve to obtain an OBSH finished product with a median particle size of about 10 μm. Detect the purity of the finished product and calculate the yield based on diphenyl ether as the substrate.

[0051] The measured purity of OBSH is 98.9%, and the yield of OBSH calculated based on diphenyl ether is 95.7%. It can be seen that increasing the feeding amount of chlorosulfonic acid has some positive promotion effects on the purity and yield of OBSH, but it will generate more three wastes.

[0052] Example 4

[0053] (1) Mix 200 g of chlorosulfonic acid with 320 g of dichloroethane and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction material to be kept at 40°C, and control the dropping rate to drop 60 g of diphenyl ether within 1 h. The tail gas generated during the dropping and reaction processes is cooled with 0-5°C cold brine and then absorbed with sodium hydroxide solution. After the dropping is completed, add 6 g of sodium chloride, and keep the material at 40°C for a reaction for 2 h. After the holding reaction is completed, drop 50 g of water to decompose the excessive chlorosulfonic acid, and at the same time extract the concentrated sulfuric acid generated by the reaction into the water. Separate the liquid to obtain the upper intermediate - dichloromethane solution. Wash the intermediate - dichloroethane solution with a sodium hydroxide solution with a concentration of 5-10 wt% until the pH is 6-7. After alkali washing, separate the liquid to take the organic phase to obtain the alkali-washed intermediate - dichloromethane solution.

[0054] (2) Mix 43 g of hydrazine hydrate (concentration 85%) with 40 g of ammonia water (concentration 25%), and then put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction materials to keep warm at 40 °C. Dropwise add the intermediate-dichloromethane solution after alkali washing in step (1) into the flask, and the dropping time is 1 h. The tail gas generated during the dropping and reaction process is cooled with 0-5 °C cold brine and then absorbed with hydrochloric acid solution. After the dropping is completed, the materials are kept warm and reacted at 40 °C for 1 h. After the heat preservation reaction is completed, the materials are gradually cooled to 5 °C to precipitate OBSH. Filter OBSH and dry it.

[0055] (3) Grind the dry OBSH product and sieve it through a 1000-mesh sieve to obtain an OBSH finished product with a median particle size of about 10 μm. Detect the purity of the finished product and calculate the yield based on diphenyl ether as the substrate.

[0056] The measured purity of OBSH is 96.2%, and the yield of OBSH calculated based on diphenyl ether is 93.4%.

[0057] Comparative Example 1

[0058] Put 200 g of chlorosulfonic acid into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction materials to keep warm at 30 °C, and control the dropping rate to drop 60 g of diphenyl ether in 2 h. The tail gas generated during the dropping and reaction process is cooled with 0-5 °C cold brine and then absorbed with sodium hydroxide solution. Since no organic solvent is introduced before the reaction, the reaction process is viscous and the reaction materials cannot be evenly distributed, which is not suitable for industrialization. After the heat preservation reaction is completed, add 280 g of dichloromethane to dissolve the materials, drop in 50 g of water to decompose the excessive chlorosulfonic acid, and at the same time extract the concentrated sulfuric acid generated by the reaction into the water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Add 50 g of water to prevent evaporation to dryness, and distill the materials in a rotary evaporator at 60 °C until no distillate is produced. After washing and drying the obtained white solid particles, an intermediate semi-finished product is obtained. The measured purity of the intermediate is 86.7%, and the yield of the intermediate is calculated to be 68.3%.

[0059] Comparative Example 2

[0060] 60 g of diphenyl ether was mixed with 280 g of dichloromethane and then put into a three-necked flask with a jacket. The circulating ice machine was started to control the reaction material to keep the temperature at 30 °C, and 200 g of chlorosulfonic acid was added dropwise over 2 h while controlling the dropping rate. The tail gas generated during the dropping and reaction process was cooled with 0 - 5 °C cold brine and then absorbed with sodium hydroxide solution. The material was kept at 30 °C for reaction for 2 h. After the heat preservation reaction was completed, 50 g of water was added dropwise to decompose the excessive chlorosulfonic acid, and at the same time, the concentrated sulfuric acid generated by the reaction was extracted into the water. Liquid separation was carried out to obtain the upper intermediate - dichloromethane solution. 50 g of water was added to prevent dry distillation, and the material was distilled at 60 °C in a rotary evaporator until no distillate was produced. After the obtained white solid particles were washed with water and dried, the intermediate semi-finished product was obtained. The purity of the intermediate was measured to be 88.6%, and the yield of the intermediate was calculated to be 87.6%.

[0061] Comparative Example 3

[0062] (1) The steps for synthesizing the intermediate - dichloromethane solution were the same as in Example 1.

[0063] (2) The intermediate - dichloromethane solution obtained in step (1) was put into a three-necked flask with a jacket. The circulating ice machine was started to control the reaction material to keep the temperature at 30 °C. 43 g of hydrazine hydrate (concentration 85%) and 50 g of ammonia water (concentration 25%) were mixed and then added dropwise to the flask. The tail gas generated during the dropping and reaction process was cooled with 0 - 5 °C cold brine and then absorbed with hydrochloric acid solution. After the dropping was completed, the material was kept at 30 °C for reaction for 1 h. After the heat preservation reaction was completed, the material was gradually cooled to 5 °C to precipitate OBSH. The OBSH was filtered and dried.

[0064] (3) The dry OBSH product was ground and sieved through a 1000-mesh sieve to obtain an OBSH finished product with a median particle size of about 10 μm. The purity of the finished product was detected, and the yield was calculated based on diphenyl ether as the substrate. The purity of OBSH was measured to be 98.3%, and the yield of OBSH calculated based on diphenyl ether was 92.2%.

[0065] Comparative Example 4

[0066] (1) The steps for synthesizing the intermediate were the same as in Example 2.

[0067] (2) Mix 43 g of hydrazine hydrate (concentration 85%) with 50 g of ammonia water (concentration 25%), and put them into a three-necked flask with a jacket. Start the circulating ice machine to control the reaction materials at a temperature of 30 °C. Add the intermediate obtained in step (1) slurried with 300 g of water dropwise to the flask. Since the intermediate is insoluble in water and is prone to precipitate and block the dropping pipeline after being slurried with water, it is necessary to continuously stir the slurry during the dropping process and keep the dropping speed uniform. The tail gas generated during the dropping and reaction process is cooled with 0 - 5 °C cold brine and then absorbed with hydrochloric acid solution. After the dropping is completed, the material is kept at 30 °C for reaction for 1 h. After the heat preservation reaction is completed, the material is gradually cooled to 5 °C to precipitate OBSH. Filter and dry the OBSH.

[0068] (3) Grind the dry OBSH product and sieve it through a 1000-mesh sieve to obtain the OBSH finished product with a median particle size of about 15 μm. Detect the purity of the finished product and calculate the yield based on diphenyl ether. The measured purity of OBSH is 98.0%, and the yield of OBSH calculated based on diphenyl ether is 90.4%.

Claims

1. A method for synthesizing 4,4'-oxybis(benzenesulfonyl hydrazide), characterized in that It includes the following steps: (1) Drop diphenyl ether into the mixed solution of halosulfonic acid and organic solvent. After dropping, add alkali metal salt, and then keep the temperature for reaction; (2) After the reaction, drop water into the reaction solution to decompose the excessive halosulfonic acid, and then separate the organic phase by liquid separation to obtain the intermediate solution; (3) Wash the intermediate solution with alkali, and then drop the alkali-washed intermediate solution into the mixed solution of hydrazine hydrate and ammonia water. After dropping, keep the temperature for reaction, and perform post-treatment after the reaction to obtain 4,4'-oxybisbenzenesulfonyl hydrazide; In step (1), diphenyl ether is dropped at 20-40 °C, the dropping time is 2-6 h, and after dropping, continue to react at this temperature for 1-4 h; In step (1), the halosulfonic acid is chlorosulfonic acid, the organic solvent is at least one of dichloromethane, dichloroethane, and DMSO, and the alkali metal salt is sodium chloride, sodium sulfate, or potassium chloride.

2. The method according to claim 1, characterized in that: In step (1), the molar ratio of diphenyl ether to halosulfonic acid is 1:4-1:

8.

3. The method according to claim 1, characterized in that: In step (1), the molar ratio of diphenyl ether to halosulfonic acid is 1:4-1:

5.

4. The method according to claim 1, wherein: In step (1), the molar ratio of the organic solvent to diphenyl ether is 5-10:

1.

5. The method according to claim 1, characterized in that: In step (1), the molar ratio of the alkali metal salt to diphenyl ether is 0.1-1:

1.

6. The method according to claim 1, wherein: In step (3), the intermediate solution is washed with alkali using an alkali solution, and the alkali solution is sodium hydroxide solution or potassium hydroxide solution.

7. The method according to claim 6, wherein: In step (3), the concentration of the alkali solution is 5-10 w%.

8. The method according to claim 1 or 6, characterized in that: In step (3), wash with alkali until the pH of the intermediate solution is 6-7.

9. The method according to claim 1 or 6, characterized in that: It includes any one of the following conditions: Condition 1: In step (3), the molar ratio of the intermediate: hydrazine hydrate: ammonia water is 1:2-2.2:1-2.5; Condition 2: In step (3), the concentration of ammonia water is 25-28%, and the concentration of hydrazine hydrate is 80-85%; Condition 3: In step (3), drop the alkali-washed intermediate solution at 20-40 °C, the dropping time is 1-4 h, and after dropping, keep the temperature for reaction for 0.5-2 h.

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