Process for the preparation of an electronic grade perfluorobutylsulfonamide ethanol

Abstract

The application relates to the technical field of organic synthesis, in particular to a preparation method of electronic-grade perfluorobutyl sulfonamide ethanol, which comprises the following steps: (1) under the protection of nitrogen, perfluorobutyl sulfonamide, ethylene carbonate and an inorganic base are mixed, and then stirred and reacted at 110-130 DEG C for 6-12 h; (2) after the reaction is completed, the reaction liquid is acidified, an organic solvent is added for extraction, the organic phase is washed with water, the organic phase is concentrated, crystallization is carried out, and drying is carried out to obtain perfluorobutyl sulfonamide ethanol crude product; (3) the perfluorobutyl sulfonamide ethanol crude product is subjected to reduced-pressure distillation at 120-145 DEG C to obtain the electronic-grade perfluorobutyl sulfonamide ethanol. According to the preparation method, the purity of the obtained product is above 99.5%, the single-metal impurity is within 10 ppb, and the product yield is 85-90%.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, specifically to a method for preparing electronic-grade perfluorobutylsulfonamide ethanol. Background Technology

[0002] Perfluorobutyl sulfonamide ethanol is a key fluorochemical intermediate. As a hydroxyl-modified perfluorobutyl sulfonamide nonionic fluorinated surfactant, electronic grade (metal impurities <10ppb, particles <0.5μm) is exclusively supplied to wafer pre-processing. It is mainly used in five major semiconductor processes: photolithography, wet etching, wafer cleaning, photoresist raw materials, and packaging aids, and is compatible with the 28nm advanced EUV process.

[0003] The current mainstream process involves the reaction of perfluorobutyl sulfonyl fluoride with monoethanolamine at room temperature in the presence of triethylamine / inorganic base, which has the following drawbacks: (1) When the temperature fluctuation is >10℃, the hydroxyl group of monoethanolamine undergoes an esterification side reaction with sulfonyl fluoride to generate C4F9SO2CH2CH2NH2 sulfonate impurities, which are difficult to remove by distillation; (2) The reaction has extremely high requirements for moisture content. When the moisture content of the raw material is >1000ppm, perfluorobutylsulfonyl fluoride will be hydrolyzed under alkaline conditions to generate perfluorobutylsulfonic acid, which will reduce the yield. (3) Triethylamine hydrofluoric acid, a single organic acid, is soluble in solvents, and the washing wastewater contains a high concentration of organic amines, resulting in high wastewater treatment costs; (4) Post-processing purification has high energy consumption, low yield, and poor industrialization economy; (5) The content of single metal impurities in the finished products produced by industrial processing is higher than 500 ppb, which makes it difficult to meet the purity requirements of semiconductor materials; Other routes, such as perfluorobutylsulfonamide and chloroethanol / bromoethanol alkylation, involve expensive raw materials and produce significant solid waste byproducts, making large-scale production impossible. Therefore, there is an urgent need to develop novel synthetic processes with low impurities, high yields, and electronic-grade properties. Summary of the Invention

[0004] To overcome the technical shortcomings of existing processes, such as numerous side reactions, high impurities, low yields, large amounts of waste, and excessive single-metal impurities, this invention provides a method for preparing electronic-grade perfluorobutyl sulfonamide ethanol. By precisely controlling the reaction conditions, the bis(sulfonamide) byproduct can be suppressed, improving product purity and yield. Furthermore, the reaction does not require the use of solvents, and single-metal impurities can be controlled to within 10 ppb, with a product yield of 85-90%.

[0005] The technical solution adopted is as follows: A method for preparing electronic-grade perfluorobutylsulfonamide ethanol includes the following steps: (1) Under nitrogen protection, perfluorobutyl sulfonamide, ethylene carbonate and inorganic base are mixed and stirred at 110-130℃ for 6-12 h. The reaction temperature is 110-130℃. If the temperature is below 110℃, the reaction is slow and a large amount of raw materials remain. If the temperature is above 130℃, too many impurities are generated, and disubstituted impurities are easily generated. The reaction time is 6-12 h. If the reaction time is less than 6 h, the reaction is slow and a large amount of raw materials remain. If the reaction time is longer than 12 h, disubstituted impurities are easily generated. (2) After the reaction is complete, the reaction solution is acidified, an organic solvent is added for extraction, the organic phase is washed with water, the organic phase is concentrated, crystallized, and dried to obtain crude perfluorobutylsulfonamide ethanol. (3) The crude perfluorobutyl sulfonamide ethanol is subjected to vacuum distillation at 120-145 °C to obtain the electronic grade perfluorobutyl sulfonamide ethanol.

[0006] The reaction equation for this invention is as follows: ; Preferably, in step (1), the molar ratio of perfluorobutylsulfonamide, ethylene carbonate and inorganic base is 1:0.8-1.4:0.05-0.5.

[0007] More preferably, the molar ratio of the perfluorobutyl sulfonamide, ethylene carbonate, and inorganic base is 1:1.10:0.10.

[0008] Preferably, in step (1), the inorganic base is at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, cesium carbonate, sodium hydroxide, and potassium hydroxide.

[0009] More preferably, the inorganic base is potassium hydroxide. Potassium hydroxide has higher reactivity and better effect on this reaction compared to other bases, which is more conducive to the reaction, and it is also relatively inexpensive.

[0010] Preferably, in step (1), the reaction temperature is 118-123 ℃ and the reaction time is 9.5-10.5 h.

[0011] Preferably, the step of acidifying the reaction solution, adding an organic solvent for extraction, separating the liquid phase, and washing the organic phase with water includes the following steps: cooling the reaction solution to room temperature after the reaction is complete, adding deionized water, and adding a 15-25 wt% sulfuric acid solution dropwise. After the addition, the pH of the solution is between 2 and 4. Then, the solution is stirred at room temperature for 2-4 hours, followed by extraction with methyl tert-butyl ether. The solution is allowed to stand and separate, and the aqueous phase is back-extracted with methyl tert-butyl ether. The organic phases are combined and washed with water. More preferably, the concentration of the sulfuric acid solution is 19-21 wt%. The amount of dilute sulfuric acid added will have a certain impact on the product yield. A smaller amount will result in a lower yield and more impurities, which is not conducive to subsequent removal. Methyl tert-butyl ether is a preferred solvent because it has better solubility for the product compared to other solvents, which is more beneficial for post-processing.

[0012] Preferably, the crystallization process includes: adding toluene to the concentrated material, heating to 50-60 °C and stirring until dissolved, maintaining the temperature and stirring for 0.6-1.5 h, and then filtering while hot to remove mechanical impurities. The filtrate is then cooled to 15-20 °C to precipitate crystals, and filtered to obtain a filter cake. This crystallization process achieves good crystallization results and effectively removes impurities.

[0013] Preferably, in step (3), the pressure of the vacuum distillation is 30-70 Pa.

[0014] Preferably, in step (3), the temperature of the vacuum distillation is 130-135 °C.

[0015] The beneficial effects of this invention are: 1. The perfluorobutylsulfonamide ethanol prepared by this invention has significantly reduced impurities: there are no disubstituted impurities, the purity of the finished product is ≥99.5%, and the single metal impurities are ≤10 ppb.

[0016] 2. The reaction process of this invention is solvent-free, and the product yield is 85-90%, which is higher than that of traditional processes.

[0017] 3. This invention is environmentally friendly and safe, generates no fluoride solid waste, reduces the amount of washing wastewater, contains no organic alkali, has a methyl tert-butyl ether recovery rate of ≥90%, and the solvent can be reused repeatedly. Detailed Implementation

[0018] To further illustrate the present invention, a detailed description is provided below with reference to specific embodiments.

[0019] Example 1:

[0020] A method for preparing electronic-grade perfluorobutylsulfonamide ethanol includes the following steps: 20.0 g of perfluorobutylsulfonamide solid was poured into a 100 mL three-necked flask, 0.37 g of potassium hydroxide powder was added, and the mixture was purged three times with magnetic nitrogen. Under nitrogen protection, 6.47 g of ethylene carbonate was added, and stirring was started. The temperature was gradually raised to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed that the purity was greater than 95%, and the remaining raw material was less than 1%. After the reaction was completed, the temperature was lowered to room temperature.

[0021] Add 12 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Maintain the temperature at 20-25 °C. After the addition is complete, the solution pH should be 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After freeing, add 15 mL of methyl tert-butyl ether (MTBE), continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 7 mL of MTBE to separate the upper organic phase B. Combine organic phases A and B, add 20 mL of deionized water again, stir for 15 min, and let stand for 30 min to obtain a total organic phase of 45 g. Concentrate the organic layer under reduced pressure at 40±5 °C to remove MTBE (recovered MTBE can be reused). Concentrate until no liquid flows out, then continue concentration for 1 h. Take a sample for GC analysis, requiring solvent residue to be less than 2%. The concentration pressure is 0.1. MPa, concentrated to the final liquid form of an oily substance, yielding 25 g of oily substance.

[0022] Add 50 g of toluene to 25 g of oily substance, heat to 50 ℃ and stir until dissolved. Continue stirring at 50 ℃ for 1 h, then filter while hot to remove mechanical impurities. Then cool to 18 ℃ and keep warm for 1 h to precipitate crystals. Filter to obtain 25 g of filter cake, dry at 60 ℃ for 12 h to obtain 22.1 g of solid crude product. GC detection showed a purity greater than 98%.

[0023] The obtained 22.1 g of crude solid product was added to a 100 mL single-necked flask, connected to a quartz distillation apparatus and an oil pump. Vacuum distillation was started by gradually increasing the temperature under an absolute pressure of 50 Pa. When the oil bath temperature reached 130-135 °C, the main fraction was collected. The distillation temperature did not exceed 145 °C. When no more fractions were produced, the temperature was lowered and nitrogen gas was released to ventilate the flask, yielding 20 g of a white solid product, perfluorobutylsulfonamide ethanol. The GC purity was greater than 99.5%, the yield was 87%, and the single metal content was less than 10 ppb according to ICP-MSMS analysis, indicating that it was electronic grade perfluorobutylsulfonamide ethanol.

[0024] Example 2:

[0025] A method for preparing electronic-grade perfluorobutylsulfonamide ethanol includes the following steps: 100.0 g of perfluorobutylsulfonamide solid was poured into a 500 mL three-necked flask, 1.87 g of potassium hydroxide powder was added, and the mixture was purged three times with magnetic nitrogen. Under nitrogen protection, 32.37 g of ethylene carbonate was added, and stirring was started. The temperature was gradually raised to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed that the purity was greater than 95%, and the remaining raw material was less than 1%. After the reaction was completed, the temperature was lowered to room temperature.

[0026] Add 60 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Maintain the temperature at 20-25 °C. After the addition is complete, the solution pH should be 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After freeing, add 90 mL of methyl tert-butyl ether (MTBE), continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the liquid phases, separating the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 35 mL of MTBE to separate the upper organic phase B. Combine organic phases A and B, add 100 mL of deionized water again, stir for 15 min, and let stand for 30 min to obtain a total organic phase of 230 g. Concentrate the organic layer under reduced pressure at 40±5 °C to remove MTBE (recovered MTBE can be reused). Concentrate until no liquid flows out, then continue concentration for 1 h. Sample and analyze for GC, requiring solvent residue to be less than 2%. The concentration pressure is 0.1. MPa, concentrated to the final liquid form of an oily substance, yielding 155 g of oily substance.

[0027] 250 g of toluene was added to 155 g of oily substance, and the mixture was heated to 50 °C and stirred until dissolved. After stirring at 50 °C for 1 h, the mixture was filtered while hot to remove mechanical impurities. Then the mixture was cooled to 18 °C and kept at that temperature for 1 h to precipitate crystals. The filtered cake was 130 g and dried at 60 °C for 12 h to obtain 112.5 g of crude solid product. The purity was greater than 98% as determined by GC.

[0028] The obtained 112.5 g of crude solid product was added to a 250 mL single-necked flask, connected to a quartz distillation apparatus and an oil pump. Vacuum distillation was initiated by gradually increasing the temperature under an absolute pressure of 50 Pa. The main fraction was collected when the oil bath temperature reached 130-135 °C. The distillation temperature did not exceed 145 °C. When no more fractions were produced, the product was cooled and purged with nitrogen gas to obtain 101.5 g of a white solid product, perfluorobutylsulfonamide ethanol. The GC purity was greater than 99.5%, the yield was 88.2%, and ICP-MS analysis showed that the single metal content was less than 10 ppb, indicating it was electronic-grade perfluorobutylsulfonamide ethanol.

[0029] Example 3:

[0030] A method for preparing electronic-grade perfluorobutylsulfonamide ethanol includes the following steps: 219.5 g of perfluorobutylsulfonamide solid was poured into a 1000 mL three-necked flask, 4.10 g of potassium hydroxide powder was added, and the mixture was purged three times with magnetic nitrogen. Under nitrogen protection, 71.05 g of ethylene carbonate was added, and stirring was started. The temperature was gradually raised to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed that the purity was greater than 95%, and the remaining raw material was less than 1%. After the reaction was completed, the temperature was lowered to room temperature.

[0031] Add 132 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Maintain the temperature at 20-25 °C. After the addition is complete, the solution pH should be 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After freeing, add 197.55 mL of methyl tert-butyl ether (MTBE), continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the liquid phases, separating the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 77 mL of MTBE, separating the upper organic phase B. Combine organic phases A and B, add 220 mL of deionized water, stir for 15 min, and let stand for 30 min to obtain a total organic phase of 512.50 g. Maintain the organic layer temperature at 40±5 °C under reduced pressure to remove concentrated MTBE (recovered MTBE can be reused). Concentrate until no liquid flows out, then continue concentration for 1 h. Sample and analyze for GC, requiring solvent residue to be less than 2%. The concentration pressure is 0.1. MPa, concentrated to the final liquid form of an oily substance, yielding 345 g of oily substance.

[0032] 550 g of toluene was added to 345 g of oily substance, and the mixture was heated to 50 °C and stirred until dissolved. After stirring at 50 °C for 1 h, the mixture was filtered while hot to remove mechanical impurities. Then the mixture was cooled to 18 °C and kept at that temperature for 1 h to precipitate crystals. The filtered cake was 290 g and dried at 60 °C for 12 h to obtain 248.7 g of crude solid product. The purity was greater than 98% as determined by GC.

[0033] The obtained 248.7 g of crude solid product was added to a 500 mL single-necked flask, connected to a quartz distillation apparatus and an oil pump. Vacuum distillation was initiated by gradually increasing the temperature under an absolute pressure of 50 Pa. The main fraction was collected when the oil bath temperature reached 130-135 °C. The distillation temperature did not exceed 145 °C. When no more fractions were produced, the product was cooled and purged with nitrogen gas to obtain 230.2 g of a white solid product, perfluorobutylsulfonamide ethanol. The GC purity was greater than 99.5%, the yield was 99.1%, and ICP-MS analysis showed that the single metal content was less than 10 ppb, indicating it was electronic-grade perfluorobutylsulfonamide ethanol.

[0034] Comparative Example 1: 20.0 g of perfluorobutylsulfonamide solid was poured into a 100 mL three-necked flask, 10.9 g of cesium carbonate powder was added, and the mixture was purged three times with magnetic nitrogen. Under nitrogen protection, 6.47 g of ethylene carbonate was added, and stirring was started. The temperature was gradually raised to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed a purity of 25%, with 70% of the raw material remaining.

[0035] Comparative Example 2: 20.0 g of perfluorobutylsulfonamide solid was poured into a 100 mL three-necked flask, and 0.37 g of potassium hydroxide powder was added. The mixture was then purged three times with magnetic nitrogen. Under nitrogen protection, 8.8 g of ethylene carbonate was added, and stirring was started. The temperature was gradually increased to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed a purity of 80%, with less than 1% of the raw material remaining, and 15% of disubstituted impurities were formed. After the reaction was complete, the mixture was cooled to room temperature.

[0036] Add 12 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Maintain the temperature at 20-25 °C. After the addition is complete, the solution pH should be 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After freeing, add 15 mL of methyl tert-butyl ether (MTBE), continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 7 mL of MTBE to separate the upper organic phase B. Combine organic phases A and B, add 20 mL of deionized water again, stir for 15 min, and let stand for 30 min to obtain a total organic phase of 45 g. Concentrate the organic layer under reduced pressure at 40±5 °C to remove MTBE (recovered MTBE can be reused). Concentrate until no liquid flows out, then continue concentration for 1 h. Take a sample for GC analysis, requiring solvent residue to be less than 2%. The concentration pressure is 0.1. MPa, concentrated to the final liquid form of an oily substance, yielding 26.4 g of oily substance.

[0037] 50 g of toluene was added to 26.4 g of oily substance, and the mixture was heated to 50 °C and stirred until dissolved. After stirring at 50 °C for 1 h, the mixture was filtered while hot to remove mechanical impurities. Then the mixture was cooled to 18 °C and kept at that temperature for 1 h to precipitate crystals. The filtered cake was 26.3 g and dried at 60 °C for 12 h to obtain 22.6 g of crude solid product. The purity was determined to be 81% by GC analysis.

[0038] The obtained 22.6 g of crude solid product was added to a 100 mL single-necked flask, connected to a quartz distillation apparatus and an oil pump. Vacuum distillation was started by gradually increasing the temperature under an absolute pressure of 50 Pa. When the oil bath temperature reached 130-135 °C, the main fraction was collected. The distillation temperature did not exceed 145 °C. When no more fractions were produced, the temperature was lowered and nitrogen gas was released to ventilate the flask, yielding 15.2 g of white solid product with a GC purity greater than 99.5%, a yield of 66.1%, and a single metal content of less than 10 ppb as determined by ICP-MSMS.

[0039] Comparative Example 3: 20.0 g of perfluorobutylsulfonamide solid was poured into a 100 mL three-necked flask, 0.37 g of potassium hydroxide powder was added, and the mixture was purged three times with magnetic nitrogen. Under nitrogen protection, 6.47 g of ethylene carbonate was added, and stirring was started. The temperature was gradually raised to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 16 h. GC analysis showed a purity of 75%, with less than 1% of the raw material remaining and 20% of disubstituted impurities. After the reaction was completed, the temperature was lowered to room temperature.

[0040] Add 12 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Maintain the temperature at 20-25 °C. After the addition is complete, the solution pH should be 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After freeing, add 15 mL of methyl tert-butyl ether (MTBE), continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 7 mL of MTBE to separate the upper organic phase B. Combine organic phases A and B, add 20 mL of deionized water again, stir for 15 min, and let stand for 30 min to obtain a total organic phase of 45 g. Concentrate the organic layer under reduced pressure at 40±5 °C to remove MTBE (recovered MTBE can be reused). Concentrate until no liquid flows out, then continue concentration for 1 h. Take a sample for GC analysis, requiring solvent residue to be less than 2%. The concentration pressure is 0.1. MPa, concentrated to the final liquid form of an oily substance, yielding 24.1 g of oily substance.

[0041] 50 g of toluene was added to 24.1 g of oily substance, and the mixture was heated to 50 °C and stirred until dissolved. After stirring at 50 °C for 1 h, the mixture was filtered while hot to remove mechanical impurities. Then the mixture was cooled to 18 °C and kept at that temperature for 1 h to precipitate crystals. The filtered cake was 22.5 g and dried at 60 °C for 12 h to obtain 20.1 g of crude solid product. The purity was greater than 76% as determined by GC.

[0042] The obtained 20.1 g of crude solid product was added to a 100 mL single-necked flask, connected to a quartz distillation apparatus and an oil pump. Vacuum distillation was started by gradually increasing the temperature under an absolute pressure of 50 Pa. When the oil bath temperature reached 130-135 °C, the main fraction was collected. The distillation temperature did not exceed 145 °C. When no more fractions were produced, the temperature was lowered and nitrogen gas was released to ventilate the flask, yielding 13.4 g of white solid product with a GC purity greater than 99.5% and a yield of 58%. ICP-MS analysis showed that the single metal content was less than 10 ppb.

[0043] Comparative Example 4: 20.0 g of perfluorobutylsulfonamide solid was poured into a 100 mL three-necked flask, 0.37 g of potassium hydroxide powder was added, and the mixture was purged three times with magnetic nitrogen. Under nitrogen protection, 6.47 g of ethylene carbonate was added, and stirring was started. The temperature was gradually raised to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed that the purity was greater than 95%, and the remaining raw material was less than 1%. After the reaction was completed, the temperature was lowered to room temperature.

[0044] Add 12 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Control the temperature at 20-25 ℃. After the addition is complete, the pH of the solution is 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After the free state is achieved, add 16 mL of ethyl acetate, continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the liquid to obtain the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 7 mL of ethyl acetate to obtain the upper organic phase B. Combine organic phases A and B, add 20 mL of deionized water again, stir for 15 min, and let stand for 30 min to obtain a total of 35 g of organic phase. Concentrate the organic layer under reduced pressure at 40±5 ℃ to remove ethyl acetate. Concentrate until no liquid flows out, and continue to concentrate for 1 h. Take a sample to test for GC, requiring solvent residue to be less than 2%. The concentration pressure is 0.1 MPa. Concentrate until the final liquid is an oily substance, producing 15 g of oily substance.

[0045] Add 50 g of toluene to 15 g of oily substance, heat to 50 ℃ and stir until dissolved. Continue stirring at 50 ℃ for 1 h, then filter while hot to remove mechanical impurities. Then cool to 18 ℃ and keep warm for 1 h to precipitate crystals. Filter to obtain 14 g of filter cake, dry at 60 ℃ for 12 h to obtain 12 g of solid crude product. GC detection showed that the purity was greater than 98%, but the yield was low.

[0046] Comparative Example 5: 20.5 g of perfluorobutylsulfonamide solid was poured into a 100 mL three-necked flask, and 0.37 g of potassium hydroxide powder was added. The mixture was then purged three times with magnetic nitrogen. Under nitrogen protection, 8.8 g of ethylene carbonate was added, and stirring was started. The temperature was gradually increased to 120 °C. When the temperature reached 80 °C, the solid raw material was completely dissolved. The reaction was carried out at 120 °C for 10 h. GC analysis showed a purity of 80%, with less than 1% of the raw material remaining, and 15% of disubstituted impurities were formed. After the reaction was complete, the mixture was cooled to room temperature.

[0047] Add 12 mL of deionized water to the reaction flask and add dropwise a 20 wt% sulfuric acid solution. Maintain the temperature at 20-25 °C. After the addition is complete, the solution pH should be 2.2-2.8. Stir at room temperature for 3 h to achieve a free state. After freeing, add 15 mL of methyl tert-butyl ether (MTBE), continue stirring for 15 min, then stop stirring and let stand for 30 min. Separate the upper organic phase A and the lower aqueous phase C. Extract the lower aqueous phase C again with 7 mL of MTBE to separate the upper organic phase B. Combine organic phases A and B, add 20 mL of deionized water again, stir for 15 min, and let stand for 30 min to obtain a total organic phase of 45 g. Concentrate the organic layer under reduced pressure at 40±5 °C to remove MTBE (recovered MTBE can be reused). Concentrate until no liquid flows out, then continue concentration for 1 h. Take a sample for GC analysis, requiring solvent residue to be less than 2%. The concentration pressure is 0.1. MPa, concentrated to the final liquid form of an oily substance, yielding 26.4 g of oily substance.

[0048] The obtained 26.4 g of oily substance was added to a 100 mL single-necked flask, connected to a quartz distillation apparatus and an oil pump. Vacuum distillation was started by gradually increasing the temperature under an absolute pressure of 50 Pa. When the oil bath temperature reached 130-135 ℃, the main fraction was collected. The distillation temperature did not exceed 145 ℃. When no more fractions were produced, the temperature was lowered and nitrogen gas was released to ventilate the flask, yielding 19.3 g of white solid product with a GC purity of 95% and a yield of 85%. ICP-MS analysis showed that the single metal content was greater than 200 ppb.

[0049] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing electronic-grade perfluorobutylsulfonamide ethanol, characterized in that, Includes the following steps: (1) Under nitrogen protection, perfluorobutyl sulfonamide, ethylene carbonate and inorganic base are mixed and stirred at 110-130 °C for 6-12 h. (2) After the reaction is complete, the reaction solution is acidified, an organic solvent is added for extraction, the organic phase is washed with water, the organic phase is concentrated, crystallized, and dried to obtain crude perfluorobutylsulfonamide ethanol. (3) The crude perfluorobutyl sulfonamide ethanol is subjected to vacuum distillation at 120-145 °C to obtain the electronic grade perfluorobutyl sulfonamide ethanol.

2. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 1, characterized in that, In step (1), the molar ratio of perfluorobutylsulfonamide, ethylene carbonate and inorganic base is 1:0.8-1.4:0.05-0.

5.

3. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 2, characterized in that, The molar ratio of perfluorobutylsulfonamide, ethylene carbonate and inorganic base is 1:1.10:0.

10.

4. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 1, characterized in that, In step (1), the inorganic base is at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, cesium carbonate, sodium hydroxide, and potassium hydroxide.

5. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 4, characterized in that, The inorganic base is potassium hydroxide.

6. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 1, characterized in that, In step (1), the reaction temperature is 118-123 ℃ and the reaction time is 9.5-10.5 h.

7. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 1, characterized in that, The process of acidifying the reaction solution, adding an organic solvent for extraction, separating the liquid phase, and washing the organic phase with water includes the following steps: cooling the reaction solution to room temperature after the reaction is completed, adding deionized water, and adding a 15-25 wt% sulfuric acid solution dropwise. After the addition is completed, the pH of the solution is between 2 and 4. Then, the solution is stirred at room temperature for 2-4 hours, followed by extraction with methyl tert-butyl ether. The solution is allowed to stand and then separated. The aqueous phase is back-extracted with methyl tert-butyl ether, and the organic phases are combined and washed with water.

8. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol as described in claim 1, characterized in that, The crystallization process includes: adding toluene to the concentrated material, heating to 50-60 ℃ and stirring until dissolved, maintaining the temperature and stirring for 0.6-1.5 h, filtering while hot to remove mechanical impurities, cooling the filtrate to 15-20 ℃ to precipitate crystals, and filtering to obtain a filter cake.

9. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol according to any one of claims 1-8, characterized in that, In step (3), the pressure of the vacuum distillation is 30-70 Pa.

10. The method for preparing electronic-grade perfluorobutylsulfonamide ethanol according to any one of claims 1-8, characterized in that, In step (3), the temperature of the vacuum distillation is 130-135 ℃.