Method for synthesizing 4, 4 '-oxybisbenzenesulfonyl hydrazide

Abstract

The invention discloses a method for synthesizing 4, 4 '-oxydibenzenesulfonyl hydrazide, which comprises the following steps of: dropwise adding diphenyl ether into a mixed solution of halosulfonic acid and an organic solvent, and adding alkali metal salt to carry out heat preservation reaction after dropwise adding; dropwise adding water to decompose excessive chlorosulfonic acid after heat preservation reaction, and performing liquid separation to obtain an intermediate solution; and carrying out alkali washing on the intermediate solution, dropwise adding the intermediate solution into a mixed solution of hydrazine hydrate and ammonia water, carrying out heat preservation, and carrying out post-treatment to obtain the product. The steps of intermediate distillation, filtration and washing purification are omitted, reaction procedures and energy consumption are reduced, and the yield of three wastes is small; meanwhile, by optimizing the synthesis steps, the finally obtained product is high in purity, high in molar yield and stable in quality.

Description

Technical Field

[0001] The invention relates to a method for synthesizing 4,4'-oxybisbenzenesulfonyl hydrazide, in particular to a method for synthesizing 4,4'-oxybisbenzenesulfonyl hydrazide which is simple to operate and does not require extraction of intermediates, and belongs to the technical field of organic fine chemicals. Background Art

[0002] 4,4-Oxobisbenzenesulfonylhydrazine (OBSH) foaming agent is the most important sulfonylhydrazine foaming agent. It has a moderate decomposition temperature and a uniform pore structure. It can be decomposed into non-toxic nitrogen and water. The residue does not affect the electrical insulation. It is widely used in rubber, plastic, polyurethane and other materials. It has significant advantages in wire and cable materials, and is called a universal foaming agent. Traditional PE foam mats, sealing strips and other rubber products are made by foaming AC through decomposition to produce gas foaming. The decomposition product of AC will produce the harmful substance formamide. Formamide is a toxic substance that is slightly irritating to human skin, easily causes allergies, and is harmful to the human body. The limit value of formamide set by the European Union in October 2015 is ≦200mg / kg. my country does not have a corresponding national standard for the time being, but the use of environmentally friendly foaming agent OBSH instead of environmentally unfriendly traditional foaming agent AC is the current trend in the foaming agent industry.

[0003] CN106588703A proposes a method for preparing 4,4-oxybisbenzenesulfonyl hydrazide (OBSH) intermediate 4,4-oxybisbenzenesulfonyl 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 of water, and the reaction conditions are harsh.

[0004] CN104072393A proposes a method for preparing 4,4-oxybisbenzenesulfonyl chloride (intermediate), in which chlorine gas and sulfur dioxide gas are introduced into diphenyl ether to carry out chlorination and sulfonation reactions. The reaction steps are complicated and it is difficult to realize industrialization.

[0005] CN114436907A proposes a method for preparing OBSH from an intermediate, wherein the intermediate is mixed with water and then dripped into hydrazine hydrate. Since the intermediate is insoluble in water, it is very easy to block the pipeline during the dripping process, making it difficult to control the dripping speed and causing large differences between reaction batches.

[0006] At present, the research on OBSH is mostly focused on the synthesis of intermediates. There are few studies on the direct synthesis of OBSH from raw materials such as diphenyl ether. The related research has the disadvantages of harsh reaction conditions, unsuitability for industrialization, and difficult treatment of three wastes. In addition, there are many by-products in the synthesis process of intermediates, and the yield is low. The synthesized intermediates need to be extracted by distillation, filtration, water washing and purification, and then used to synthesize OBSH, which is cumbersome. Summary of the invention

[0007] Aiming at the shortcomings of the existing method for synthesizing 4,4'-oxybisbenzenesulfonyl hydrazide, the present invention provides a method for synthesizing 4,4'-oxybisbenzenesulfonyl hydrazide, which does not require the intermediate to be separated and purified before the next step, thus saving the production process, reducing the consumption of three wastes, and being more suitable for industrial production.

[0008] The specific technical solutions of the present invention are as follows: A method for synthesizing 4,4'-oxybisbenzenesulfonylhydrazide, the method comprising the following steps: (1) Add diphenyl ether dropwise into a mixture of halosulfonic acid and an organic solvent, add an alkali metal salt after the addition is complete, and then keep the mixture warm for reaction; (2) After the reaction is completed, water is added dropwise to the reaction solution to decompose the excess halosulfonic acid, and then the organic phase is separated to obtain an intermediate solution; (3) The intermediate solution is subjected to alkali washing, and then the intermediate solution after alkali washing is dripped into a mixed solution of hydrazine hydrate and ammonia water. After the dripping is completed, the solution is kept warm for reaction, and after the reaction, post-treatment is performed to obtain 4,4'-oxybisbenzenesulfonylhydrazine.

[0009] In the present invention, diphenyl ether and chlorosulfonic acid are first subjected to sulfonation and then to chlorination reaction to obtain an intermediate, and then the intermediate is reacted with hydrazine hydrate and ammonia water to obtain a final product, and the reaction formula is as follows: Furthermore, in the above step (1), the halosulfonic acid may be chlorosulfonic acid, fluorosulfonic acid, etc. The molar ratio of diphenyl ether to chlorosulfonic acid is 1:4 to 1:8, for example, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8. In order to make the diphenyl ether react completely and generate less wastewater, the preferred molar ratio is 1:4 to 1:5.

[0010] Furthermore, in the above step (1), the diphenyl ether is added for 2 to 6 hours, for example, 2 hours, 3 hours, 4 hours, 5 hours, and 6 hours. The diphenyl ether is added at a temperature of 20 to 40° C., for example, 20° C., 30° C., and 40° C. In the present invention, diphenyl ether is added dropwise to a mixture of a halosulfonic acid and an organic solvent, which can better reduce the occurrence of side reactions and improve the yield.

[0011] Furthermore, in the above step (1), the organic solvent is at least one of dichloromethane, dichloroethane, and DMSO (dimethyl sulfoxide).

[0012] Furthermore, in the above step (1), the molar ratio of the organic solvent to diphenyl ether is 5-10:1, for example, 5:1, 6:1, 7:1, 8:1, 9:1, 10:1.

[0013] Furthermore, in the above step (1), after the diphenyl ether is dripped, an alkali metal salt is added to consume the concentrated sulfuric acid produced as a by-product of the chlorination reaction, so that the reaction proceeds to the right, thereby improving the reaction efficiency and reaction yield.

[0014] Furthermore, 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 to 1:1, for example, 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.

[0015] Furthermore, in the above step (1), after the diphenyl ether is added, the alkali metal salt is added and the reaction is continued at 20-40° C. for 1-4 hours.

[0016] Furthermore, in the above step (2), after the reaction, water is dripped into the reaction mixture to hydrolyze the excess halosulfonic acid. The amount of water used is to remove the excess halosulfonic acid. The molar ratio of the amount of water dripped into the reaction mixture to diphenyl ether is generally 1:1 to 10, for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10. The temperature of the dripped water is not higher than room temperature, preferably 0 to 5°C, which can effectively prevent the temperature from rising during the hydrolysis of the halosulfonic acid.

[0017] Furthermore, in the above step (3), the intermediate solution is washed with an alkaline solution until the pH of the intermediate solution is 6-7, and the solution can be separated after the alkaline washing to remove the aqueous phase. The alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution, and the concentration of the alkaline solution is 5-10w%.

[0018] Furthermore, in the above step (3), the molar ratio of the intermediate: hydrazine hydrate: ammonia in aqueous ammonia is 1:2-2.2:1-2.5.

[0019] Furthermore, 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 25-28wt%, and the concentration of the hydrazine hydrate is 80-85wt%.

[0020] Furthermore, 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.

[0021] Furthermore, in the above step (3), after the dropping is completed, the reaction is continued at 20-40° C. for 0.5-2 h.

[0022] Furthermore, 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'-oxybisbenzenesulfonylhydrazine. 4,4'-oxybisbenzenesulfonylhydrazine is ground and sieved to obtain 4,4'-oxybisbenzenesulfonylhydrazine of different particle sizes.

[0023] The present invention has the following beneficial effects: (1) The present invention improves the yield and purity of the intermediate by adjusting the order of adding raw materials, adding alkali metal salts to remove by-products during the preparation of the intermediate, adding water to remove halosulfonic acid after the reaction, and alkali washing the intermediate solution. The intermediate does not need to be purified and separated, and can be directly reacted with hydrazine hydrate to generate 4,4'-oxybisbenzenesulfonyl hydrazide after alkali washing, thereby saving reaction steps and energy consumption, and reducing the amount of three wastes.

[0024] (2) The present invention drips diphenyl ether into the halosulfonic acid, so that the halosulfonic acid is in excess at the beginning of the reaction, which promotes the reaction. At the same time, the reaction process is controlled by the dripping speed to reduce the occurrence of side reactions. Moreover, dripping diphenyl ether instead of the highly corrosive halosulfonic acid can effectively prevent the raw materials from corroding the dripping pipeline.

[0025] (3) In the present invention, an appropriate amount of alkali metal salt is added during the heat preservation stage after the diphenyl ether is added dropwise, so that the concentrated sulfuric acid by-product produced in the chlorination stage can be continuously consumed, thereby promoting the forward reaction and making the yield of the intermediate reach up to more than 95%.

[0026] (4) The present invention adopts a reaction method of dropping the intermediate solution into hydrazine hydrate, which can effectively control the particle size of OBSH generated by the reaction. After filtering, washing and drying, it is convenient to process into finished products of different particle sizes through grinding and screening, and the product quality is more stable. DETAILED DESCRIPTION

[0027] The present invention is further described below by means of specific embodiments. The following description is only exemplary and does not limit the content thereof.

[0028] Unless otherwise specified, the following concentrations are all mass percentages.

[0029] Example 1 (1) Mix 200g of chlorosulfonic acid and 280g of dichloromethane and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30℃. Control the dripping speed for 2h and drip 60g of diphenyl ether. The tail gas generated during the dripping and reaction process is cooled with 0~5℃ cold brine and then absorbed with sodium hydroxide solution. After the dripping is completed, 5g of sodium chloride is added, and the material is kept warm at 30℃ for 2h. After the insulation reaction is completed, 50g of water is dripped to decompose the excess chlorosulfonic acid, and the concentrated sulfuric acid produced by the reaction is extracted into the water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Use a sodium hydroxide solution with a concentration of 5-10wt% 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.

[0030] (2) Mix 43g of hydrazine hydrate (concentration 85%) and 50g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30°C. Add the intermediate-dichloromethane solution after alkali washing in step (1) dropwise into the flask for 1 hour. The tail gas generated during the dropwise addition and reaction process is cooled with 0-5°C cold brine and then absorbed with hydrochloric acid solution. After the dropwise addition is completed, the material is kept warm at 30°C for 1 hour. After the insulation reaction is completed, the material is gradually cooled to 5°C to precipitate OBSH, and the OBSH is filtered and dried.

[0031] (3) Grind the dried OBSH product and sieve it through a 1000-mesh sieve to obtain a finished OBSH product with a median particle size of about 10 μm. Test the purity of the finished product and calculate the yield based on diphenyl ether.

[0032] The purity of OBSH is tested according to the purity test method in Q / KY002-2023 "Industrial 4, 4'-oxybisbenzenesulfonylhydrazine (OBSH foaming agent)". The theoretical mass of 100% diphenyl ether converted into OBSH is m0 = 126.327g, so the yield calculation formula of OBSH is yield = , where m is the actual mass of OBSH and c is the purity of OBSH.

[0033] The purity of OBSH was measured to be 98.8%, and the yield of OBSH calculated based on diphenyl ether was 95.3%.

[0034] Example 2 (1) Mix 200g of chlorosulfonic acid and 280g of dichloromethane and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30℃. Control the dripping speed for 2h and drip 60g of diphenyl ether. The tail gas generated during the dripping and reaction process is cooled with 0~5℃ cold brine and then absorbed with sodium hydroxide solution. After the dripping is completed, 5g of sodium chloride is added, and the material is kept warm at 30℃ for 2h. After the insulation reaction is completed, 50g of water is dripped to decompose the excess chlorosulfonic acid, and the concentrated sulfuric acid produced by the reaction is extracted into water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Add 50g of water to prevent evaporation, and distill the material at 60℃ in a rotary evaporator until no distillate is produced. Wash and dry the obtained white solid particles to obtain the intermediate. The purity of the intermediate was tested according to the purity test method in Q / KY001-2023 "Industrial 4, 4'-Oxo-Bisbenzenesulfonyl Chloride (Intermediate)", and the yield of the intermediate was calculated as follows: yield = intermediate mass * intermediate purity / (molar amount of diphenyl ether * intermediate molecular weight) * 100%. The purity of the intermediate was measured to be 98.8%, and the yield of the intermediate was calculated to be 96.2%.

[0035] (2) Mix 43 g of hydrazine hydrate (concentration 85%) and 50 g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30°C. Dissolve the intermediate obtained in step (1) in 280 g of dichloromethane, and drop the intermediate-dichloromethane solution into the flask for 1 hour. The tail gas generated during the dropwise addition and reaction process is cooled with 0-5°C cold brine and then absorbed with hydrochloric acid solution. After the dropwise addition is completed, the material is kept warm for reaction at 30°C for 1 hour. After the insulation reaction is completed, the material is gradually cooled to 5°C to precipitate OBSH. Filter OBSH and dry it.

[0036] (3) Grind the dry OBSH product and sieve it through a 1000-mesh sieve to obtain a finished OBSH product with a median particle size of about 10 μm.

[0037] The purity of OBSH was measured to be 98.5%, and the yield of OBSH calculated based on diphenyl ether was 95.1%.

[0038] Example 3 (1) Mix 328g of chlorosulfonic acid and 260g of DMSO and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30℃. Control the dripping speed for 2h and drip 60g of diphenyl ether. The tail gas generated during the dripping and reaction process is cooled with 0~5℃ cold brine and then absorbed with sodium hydroxide solution. After the dripping is completed, 5g of sodium chloride is added, and the material is kept warm at 30℃ for 2h. After the insulation reaction is completed, 300g of water is dripped to decompose the excess chlorosulfonic acid and produce a large amount of hydrochloric acid gas. At the same time, the concentrated sulfuric acid produced by the reaction is extracted into water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Use a sodium hydroxide solution with a concentration of 5-10wt% to wash the intermediate-DMSO solution 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.

[0039] (2) Mix 43g of hydrazine hydrate (concentration 85%) and 50g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30°C. Add the intermediate-dichloromethane solution after alkali washing in step (1) dropwise into the flask for 1 hour. The tail gas generated during the dropwise addition and reaction process is cooled with 0-5°C cold brine and then absorbed with hydrochloric acid solution. After the dropwise addition is completed, the material is kept warm at 30°C for 1 hour. After the insulation reaction is completed, the material is gradually cooled to 5°C to precipitate OBSH, and the OBSH is filtered and dried.

[0040] (3) Grind the dried OBSH product and sieve it through a 1000-mesh sieve to obtain a finished OBSH product with a median particle size of about 10 μm. Test the purity of the finished product and calculate the yield based on diphenyl ether.

[0041] The purity of OBSH was measured to be 98.9%, and the yield of OBSH calculated based on diphenyl ether was 95.7%. It can be seen that increasing the amount of chlorosulfonic acid added has some positive effects on the purity and yield of OBSH, but will produce more three wastes.

[0042] Example 4 (1) Mix 200g of chlorosulfonic acid and 320g of dichloroethane and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 40℃. Control the dripping speed for 1h and drip 60g of diphenyl ether. The tail gas generated during the dripping and reaction process is cooled with 0~5℃ cold brine and then absorbed with sodium hydroxide solution. After the dripping is completed, 6g of sodium chloride is added, and the material is kept warm at 40℃ for 2h. After the insulation reaction is completed, 50g of water is dripped to decompose the excess chlorosulfonic acid, and the concentrated sulfuric acid produced by the reaction is extracted into the water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Use a sodium hydroxide solution with a concentration of 5-10wt% to wash the intermediate-dichloroethane solution 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.

[0043] (2) Mix 43g of hydrazine hydrate (concentration 85%) and 40g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 40°C. Add the intermediate dichloromethane solution after alkali washing in step (1) dropwise into the flask for 1 hour. The tail gas generated during the addition and reaction process is cooled with 0-5°C cold brine and then absorbed with hydrochloric acid solution. After the addition is completed, the material is kept warm at 40°C for 1 hour. After the insulation reaction is completed, the material is gradually cooled to 5°C to precipitate OBSH, and the OBSH is filtered and dried.

[0044] (3) Grind the dried OBSH product and sieve it through a 1000-mesh sieve to obtain a finished OBSH product with a median particle size of about 10 μm. Test the purity of the finished product and calculate the yield based on diphenyl ether.

[0045] The purity of OBSH was measured to be 96.2%, and the yield of OBSH calculated based on diphenyl ether was 93.4%.

[0046] Comparative Example 1 200g of chlorosulfonic acid was put into a three-necked flask with a jacket, and the circulating ice machine was turned on to control the reaction material to keep warm at 30°C. The dripping speed was controlled to drip 60g of diphenyl ether for 2h. The tail gas generated during the dripping and reaction process was cooled with 0~5°C cold brine and then absorbed with sodium hydroxide solution. Since no organic solvent was introduced before the reaction, the reaction process was viscous, and the reaction materials could not be evenly distributed, which was not suitable for industrialization. After the insulation reaction was completed, 280g of dichloromethane was added to dissolve the material, and 50g of water was dripped to decompose the excess chlorosulfonic acid, and the concentrated sulfuric acid produced by the reaction was extracted into the water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Add 50g of water to prevent evaporation, and distill the material at 60°C in a rotary evaporator until no distillate is produced. After washing and drying the white solid particles, the intermediate semi-finished product was obtained. The purity of the intermediate was measured to be 86.7%, and the yield of the intermediate was calculated to be 68.3%.

[0047] Comparative Example 2 Mix 60g of diphenyl ether and 280g of dichloromethane and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep warm at 30°C, and control the dripping speed for 2h to drip in 200g of chlorosulfonic acid. The tail gas generated during the dripping and reaction process is cooled with 0~5°C cold brine and absorbed with sodium hydroxide solution. The material is kept warm for 2h at 30°C. After the insulation reaction is completed, 50g of water is dripped in to decompose the excess chlorosulfonic acid, and the concentrated sulfuric acid produced by the reaction is extracted into water. Separate the liquid to obtain the upper intermediate-dichloromethane solution. Add 50g of water to prevent evaporation, and distill the material at 60°C in a rotary evaporator until no distillate is produced. After washing and drying the white solid particles, the intermediate semi-finished product is obtained. The purity of the intermediate is measured to be 88.6%, and the yield of the intermediate is calculated to be 87.6%.

[0048] Comparative Example 3 (1) The steps for synthesizing the intermediate - dichloromethane solution are the same as those in Example 1.

[0049] (2) The intermediate obtained in step (1) - dichloromethane solution was placed in a three-necked flask with a jacket, and the circulating ice machine was turned on to control the reaction material to be kept warm at 30°C. 43g of hydrazine hydrate (concentration 85%) and 50g of ammonia water (concentration 25%) were mixed and then added dropwise to the flask. The tail gas generated during the addition and reaction process was cooled with 0-5°C cold brine and then absorbed with hydrochloric acid solution. After the addition was completed, the material was kept warm at 30°C for 1h. After the insulation reaction was completed, the material was gradually cooled to 5°C to precipitate OBSH. OBSH was filtered and dried.

[0050] (3) Grind the dried OBSH and sieve it through a 1000-mesh sieve to obtain a finished OBSH product with a median particle size of about 10 μm. The purity of the finished product was tested and the yield was calculated based on diphenyl ether. The purity of OBSH was measured to be 98.3%, and the yield of OBSH calculated based on diphenyl ether was 92.2%.

[0051] Comparative Example 4 (1) The steps for synthesizing the intermediate are the same as those in Example 2.

[0052] (2) Mix 43 g of hydrazine hydrate (concentration 85%) and 50 g of ammonia water (concentration 25%) and put them into a three-necked flask with a jacket. Turn on the circulating ice machine to control the reaction material to keep it warm at 30°C. Add 300 g of water to the intermediate obtained in step (1) and add it dropwise to the flask. Since the intermediate is insoluble in water, it is easy to precipitate and block the dripping pipe after slurrying with water. Therefore, the slurry needs to be stirred continuously during the dripping process and the dripping should be maintained at a uniform speed. The tail gas generated during the dripping and reaction process is cooled with 0~5°C cold brine and then absorbed with hydrochloric acid solution. After the dripping is completed, the material is kept warm for reaction at 30°C for 1 hour. After the insulation reaction is completed, the material is gradually cooled to 5°C to precipitate OBSH. Filter OBSH and dry it.

[0053] (3) Grind the dried OBSH and sieve it through a 1000-mesh sieve to obtain a finished OBSH product with a median particle size of about 15 μm. The purity of the finished product was tested and the yield was calculated based on diphenyl ether. The purity of OBSH was measured to be 98.0%, and the yield of OBSH calculated based on diphenyl ether was 90.4%.

Claims

1. A method for synthesizing 4,4'-oxybisbenzenesulfonyl hydrazide, characterized in that The following steps are involved: (1) Add diphenyl ether dropwise into a mixture of halosulfonic acid and an organic solvent, add an alkali metal salt after the addition is complete, and then keep the mixture warm for reaction; (2) After the reaction is completed, water is added dropwise to the reaction solution to decompose the excess halosulfonic acid, and then the organic phase is separated to obtain an intermediate solution; (3) The intermediate solution is subjected to alkali washing, and then the intermediate solution after alkali washing is dripped into a mixed solution of hydrazine hydrate and ammonia water. After the dripping is completed, the solution is kept warm for reaction, and after the reaction, post-treatment is performed to obtain 4,4'-oxybisbenzenesulfonylhydrazine.

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, preferably 1:4-1:5; preferably, the halosulfonic acid is chlorosulfonic acid or fluorosulfonic acid.

3. The method according to claim 1, characterized in that: In step (1), the organic solvent is at least one of dichloromethane, dichloroethane and DMSO.

4. The method according to claim 1 or 3, characterized in that: 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), diphenyl ether is added dropwise at 20-40°C for 2-6 hours, and the reaction is continued at this temperature for 1-4 hours after the addition is completed.

6. The method according to claim 1, characterized in that: In step (1), the alkali metal salt is sodium chloride, sodium sulfate or potassium chloride.

7. The method according to claim 1 or 6, characterized in that: In step (1), the molar ratio of the alkali metal salt to the diphenyl ether is 0.1 to 1:

1.

8. The method according to claim 1, characterized in that: In step (3), the intermediate solution is washed with an alkaline solution, wherein the alkaline solution is a sodium hydroxide solution or a potassium hydroxide solution; preferably, the concentration of the alkaline solution is 5-10w%.

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

10. The method according to claim 1 or 8, characterized in that: Include at least one of the following conditions: Condition 1: In step (3), the molar ratio of intermediate: hydrazine hydrate: ammonia water is 1:2-2.2:1-2.5; Condition 2: In step (3), the concentration of aqueous ammonia is 25-28%, and the concentration of hydrazine hydrate is 80-85%; Condition 3: In step (3), the intermediate solution after alkali washing is added dropwise at 20-40°C for 1-4 hours. After the addition is complete, the mixture is kept warm for 0.5-2 hours.

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