A perfluoro-4-butoxy-1-butylsulfonyl fluoride, its preparation method and application

Abstract

This application provides a perfluoro-4-butoxy-1-butylsulfonyl fluoride, its preparation method, and its application, relating to the field of chemical synthesis technology. The preparation method of the perfluoro-4-butoxy-1-butylsulfonyl fluoride according to this application includes the following steps: adding butoxybutylsulfonyl fluoride and functional additives to an electrolytic cell containing anhydrous hydrogen fluoride for an electrolytic reaction. The functional additives include alkali metal fluorides, thiols, and perfluorobutylsulfonyl fluoride, wherein the carbon chain length of the thiols is C2~C6. The preparation method of perfluoro-4-butoxy-1-butylsulfonyl fluoride can improve the yield of the target product.

Description

Technical Field

[0001] This application relates to the field of chemical synthesis technology, and more specifically, to a perfluoro-4-butoxy-1-butylsulfonyl fluoride, its preparation method and application. Background Technology

[0002] Perfluorooctyl sulfonic acid (PFOS) derivatives, derived from perfluorooctyl sulfonyl fluoride (PFOSF), are widely used in many fields due to their excellent stability and surface activity. However, PFOS exhibit typical characteristics of public organic pollutants (POPs), such as environmental persistence, bioaccumulation, long-distance migration potential, and biotoxicity. They pose potential risks to ecosystems and human health and have been strictly restricted and banned worldwide.

[0003] Perfluoro-4-butoxy-1-butylsulfonyl fluoride, namely 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride, has the following molecular structural formula: Compared to PFOSF, it has an additional oxygen atom in its carbon chain. Existing research data shows that fluorocarbon surfactants synthesized from perfluoro-4-butoxy-1-butylsulfonyl fluoride exhibit excellent surface activity and low biotoxicity, thus serving as an effective alternative to PFOS.

[0004] Currently, perfluoro-4-butoxy-1-butylsulfonyl fluoride is usually synthesized by electrochemical fluorination. In the traditional electrochemical fluorination process for synthesizing this product, butoxybutylsulfonyl fluoride and anhydrous hydrogen fluoride are mainly used to form a reaction system, which has the problem of low yield of the target product. Summary of the Invention

[0005] The purpose of this application is to provide a perfluoro-4-butoxy-1-butylsulfonyl fluoride, its preparation method and application, which can improve the yield of the target product.

[0006] In a first aspect, embodiments of this application provide a method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride, which includes the following steps: adding butoxybutylsulfonyl fluoride and functional additives into an electrolytic cell containing anhydrous hydrogen fluoride for electrolytic reaction, wherein the functional additives include alkali metal fluorides, thiols and perfluorobutylsulfonyl fluoride, and the carbon chain length of the thiols is C2~C6.

[0007] In the above technical solution, by adding butoxybutylsulfonyl fluoride and functional additives including alkali metal fluorides, thiols with specific carbon chain lengths, and perfluorobutylsulfonyl fluoride to the anhydrous hydrogen fluoride system, the reaction system is optimized, the severity of reaction conditions is reduced, side reactions are reduced, the yield of the target product and the stability of the reaction system are improved, and the efficient preparation of perfluoro-4-butoxy-1-butylsulfonyl fluoride is achieved, meeting the needs of industrial production.

[0008] In one possible implementation, the alkali metal fluoride includes at least one of potassium fluoride, lithium fluoride, sodium fluoride, and cesium fluoride; And / or, the amount of the alkali metal fluoride added is 1% to 2% of the mass of the anhydrous hydrogen fluoride.

[0009] In the above technical solution, by controlling the type and amount of alkali metal fluorides added, the conductivity of the system can be effectively improved, the reaction rate can be accelerated, the reaction efficiency and stability can be further improved, the electrolysis process can be ensured to proceed smoothly, and the reaction stagnation problem caused by insufficient conductivity can be reduced.

[0010] In one possible implementation, the thiol compound includes at least one of ethanethiol, n-propanethiol, isopropanethiol, n-butanethiol, sec-butanethiol, and 1-hexanethiol; And / or, the amount of the thiol compound added is 2% to 4% of the mass of the anhydrous hydrogen fluoride.

[0011] In the above technical solution, by controlling the type and amount of thiol compounds, highly active free radicals can be effectively captured, polymerization side reactions can be suppressed, reaction selectivity can be improved, the conductivity of the system can be enhanced, current efficiency can be improved, the yield of the target product can be increased, polymer adhesion on the electrode surface can be reduced, and the electrode life can be extended.

[0012] In one possible implementation, the amount of perfluorobutyl sulfonyl fluoride added is 2% to 4% of the mass of the anhydrous hydrogen fluoride.

[0013] In the above technical solution, by controlling the amount of perfluorobutylsulfonyl fluoride added, the reaction solution can be stabilized and diluted, the concentration of highly active free radicals can be reduced, thereby reducing the probability of side reactions. At the same time, based on the principle of like dissolves like, the product is promoted to leave the electrode region, avoiding excessive product reaction and loss, improving product yield, and stabilizing the reaction system environment.

[0014] In one possible implementation, the amount of butoxybutylsulfonyl fluoride added is 3% to 12% of the mass of the anhydrous hydrogen fluoride, optionally 5% to 10%.

[0015] In one possible implementation, the alkali metal fluoride and the perfluorobutyl sulfonyl fluoride are first added to the electrolytic cell for pre-electrolysis, and then the thiol compound and the butoxybutyl sulfonyl fluoride are added for electrolytic reaction.

[0016] In the above technical solution, by first pre-electrolyzing alkali metal fluorides and perfluorobutyl sulfonyl fluoride, and then adding thiols and butoxybutyl sulfonyl fluoride, a stable electrochemical environment can be constructed in advance, side reactions can be reduced, the stability and efficiency of the reaction system can be improved, and the foundation for the smooth progress of the subsequent main reaction can be laid, which is conducive to continuous industrial production.

[0017] In one possible implementation, the thiol compound and the butoxybutylsulfonyl fluoride are first premixed and then simultaneously added to the electrolytic cell.

[0018] In the above technical solution, adding thiol compounds and butoxybutylsulfonyl fluoride after premixing can alleviate the exothermic phenomenon during feeding, avoid the increase of side reactions caused by excessively high local temperatures, and at the same time make the materials more uniformly mixed, improve the uniformity of the reaction, ensure that the reaction is carried out in a stable temperature environment, and improve the consistency of the product.

[0019] In one possible implementation, the voltage applied during the electrolysis reaction is 4.5V to 5.0V.

[0020] In the above technical solution, the electrolysis voltage is controlled at 4.5V~5.0V, which avoids the side reaction of fluoride ions being oxidized into elemental fluorine, improves the safety and controllability of the reaction, ensures the high efficiency of the reaction, reduces power consumption, lowers production costs, and improves the economics of the reaction.

[0021] In one possible implementation, the temperature during the electrolysis reaction is -3℃ to 10℃, and can be selected as 0℃ to 5℃.

[0022] In the above technical solution, the reaction temperature is controlled between -3℃ and 10℃, or between 0℃ and 5℃, which balances the reaction yield and reaction rate. This avoids the side reaction of carbon chain breakage caused by excessively high temperature, and also avoids the problem of excessively slow reaction rate caused by excessively low temperature, thereby improving the overall efficiency of the reaction and ensuring that the reaction is carried out under optimal temperature conditions.

[0023] In one possible implementation, the electrolysis reaction causes the electrolyte in the electrolytic cell to change color to colorless; And / or, the electrolysis reaction takes 36h to 72h.

[0024] The above technical solution clarifies the criteria for determining the reaction endpoint, enabling accurate control of the reaction process, avoiding incomplete or excessive reactions, ensuring product yield and purity, achieving precise production control, improving production stability and controllability, and ensuring consistent product quality in each production run.

[0025] One possible implementation includes the following steps: S1. Add anhydrous hydrogen fluoride to the electrolytic cell and apply a voltage of 3.5V~4.0V for pre-electrolysis to remove residual moisture. After the current drops to a level that does not change for 2 consecutive hours, stop the power supply. S2. Add the alkali metal fluoride and the perfluorobutyl sulfonyl fluoride to the electrolytic cell, apply a voltage of 4.5V~5.0V for pre-electrolysis, and stop the power supply after the current rises to a level that no longer changes for 2 hours. S3. Add the butoxybutylsulfonyl fluoride and the thiol compound to the electrolytic cell, and apply a voltage of 4.5V~5.0V to carry out the electrolysis reaction.

[0026] In the above technical solution, the two-step pre-electrolysis step can effectively remove residual moisture in the system, build a stable electrochemical environment in advance, lay the foundation for the smooth progress of the subsequent main reaction, further improve the stability of the reaction and the product yield, reduce side reactions caused by the presence of moisture, and improve the reliability of the reaction.

[0027] In one possible implementation, the step of purifying the crude product obtained from the electrolysis reaction is also included; Optionally, the purification method includes: washing and drying the crude product, then performing vacuum distillation under a negative pressure of 0.01 MPa, and collecting the fraction at 88°C to 92°C.

[0028] In the above technical solution, impurities in the crude product can be effectively removed through specific purification steps to obtain the target product with high purity, which expands the application range of the compound, meets the needs of high-end application scenarios, and enhances the market competitiveness of the product.

[0029] Secondly, embodiments of this application provide a perfluoro-4-butoxy-1-butylsulfonyl fluoride, which is prepared using the method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride provided in the first aspect.

[0030] In the above technical solution, the perfluoro-4-butoxy-1-butylsulfonyl fluoride prepared by the above preparation method has high purity, high yield and stable quality, which can meet the needs of subsequent applications, promote the popularization and use of this compound, and provide a high-quality intermediate for the development of PFOS substitutes.

[0031] Secondly, embodiments of this application provide an application of the perfluoro-4-butoxy-1-butylsulfonyl fluoride provided in the second aspect, wherein the perfluoro-4-butoxy-1-butylsulfonyl fluoride is used to derivatize potassium perfluoro-4-butoxy-1-butanesulfonate.

[0032] In the above technical solution, the perfluoro-4-butoxy-1-butylsulfonyl fluoride is derived into potassium perfluoro-4-butoxy-1-butanesulfonate, which can obtain a PFOS substitute with better performance. It has higher surface activity and lower toxicity, and can be widely used in surfactants, chromium mist inhibitors and other fields, giving full play to the application value of the compound and providing a more environmentally friendly and efficient product for the chemical industry. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0034] Perfluorooctyl sulfonate (PFOS) derivatives derived from perfluorooctyl sulfonyl fluoride (PFOSF) pose potential risks to ecosystems and human health and have been strictly restricted and banned worldwide. Therefore, developing alternatives or technologies to replace PFOS has become an important research direction in the fields of environmental science and chemical engineering.

[0035] The molecular structure of perfluoro-4-butoxy-1-butylsulfonyl fluoride, namely 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride, is as follows: Its molecular structure formula is the same as that of PFOSF: In comparison, the compound has an additional oxygen atom in its carbon chain, which can serve as a key intermediate in the synthesis of sulfonates with the same carbon-fluorine chain structure, thus making it an effective alternative to PFOS. Existing research data shows that the fluorocarbon surfactant 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride—potassium 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonate—not only exhibits excellent surface activity, but its surface tension is also lower than that of similar PFOS products. When used as a chromium mist inhibitor, only about half the amount of PFOS is needed to reduce the concentration of chromic acid mist in the working environment to below the national standard. Furthermore, in HepG2 cell and zebrafish embryo toxicity experiments, this compound also showed lower biotoxicity than PFOS. In summary, this compound demonstrates significant advantages in both performance and environmental friendliness, making the development of its efficient synthesis method of significant research value and application significance.

[0036] Currently, the synthesis of perfluoro-4-butoxy-1-butylsulfonyl fluoride typically employs electrochemical fluorination (ECF), a one-step reaction that introduces fluorine atoms into organic molecules while preserving the original functional groups of the reactants. In traditional electrochemical fluorination processes, the reaction system is relatively simple, mainly consisting of butoxybutylsulfonyl fluoride as both a reactant and a conductive medium, and anhydrous hydrogen fluoride (AHF) acting as both a fluorine source and a solvent. Under this simple system, the reaction requires relatively high reactant concentrations (approximately 15%), voltages (6.0V~6.6V), and temperatures (15℃~19℃) to initiate and maintain. However, these relatively harsh operating conditions do not yield ideal synthesis efficiency; instead, they result in extremely low yields of the target product, only 0.5%~1.5%. In addition, in order to maintain the continuous operation of the reaction (with continuous periodic feeding and replenishment without interrupting the reaction to clean the electrodes), high voltage and temperature conditions must be maintained, which significantly increases the operating costs such as power consumption and heat transfer during long-term operation of the reaction.

[0037] To address the aforementioned issues, this application presents a novel technical solution. The core improvement of this solution lies in the introduction of three functional additives into the reaction system. By utilizing the combined use of these components, the electrochemical environment and reaction pathway of the reaction system are synergistically altered, thereby improving the yield of the target product and other effects.

[0038] The following provides a detailed description of the perfluoro-4-butoxy-1-butylsulfonyl fluoride, its preparation method, and its application, based on embodiments of this application.

[0039] This application provides a method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride, which includes the following steps: adding butoxybutylsulfonyl fluoride and functional additives into an electrolytic cell containing anhydrous hydrogen fluoride for electrolytic reaction, wherein the functional additives include alkali metal fluorides, thiols and perfluorobutylsulfonyl fluoride, and the carbon chain length of the thiols is C2~C6.

[0040] In this application, the chemical formula of the target product, perfluoro-4-butoxy-1-butylsulfonyl fluoride, is: ; Among the raw materials used to prepare the target product: The chemical formula of butoxybutylsulfonyl fluoride is: ; Alkali metal fluorides are compounds composed of alkali metals and fluoride ions; Thiols are organic compounds containing thiol (-SH) functional groups. The length of the carbon chain is C2 to C6, meaning that the longest continuous carbon chain in its molecular formula contains 2 to 6 carbon atoms. Examples include thiols with a carbon chain length of C2 (ethanethiol), thiols with a carbon chain length of C3 (propanethiol), thiols with a carbon chain length of C4 (butanethiol), thiols with a carbon chain length of C5 (pentanethiol), and thiols with a carbon chain length of C6 (hexanethiol). Optionally, the carbon chain length of a thiol compound is C4, meaning that the thiol compound is selected from butanethiol.

[0041] The chemical formula of perfluorobutyl sulfonyl fluoride (PFBS) is: .

[0042] This application optimizes the reaction system by adding butoxy-1-butylsulfonyl fluoride and functional additives including alkali metal fluorides, thiols with specific carbon chain lengths, and perfluoro-4-butoxy-1-butylsulfonyl fluoride to anhydrous hydrogen fluoride system. This reduces the severity of reaction conditions, decreases the occurrence of side reactions, and improves the yield of the target product and the stability of the reaction system. It achieves the efficient preparation of perfluoro-4-butoxy-1-butylsulfonyl fluoride, meeting the needs of industrial production.

[0043] Specifically, the reactant butoxybutylsulfonyl fluoride has poor conductivity, and the current is low when it is used as the only conductive medium. The addition of alkali metal fluorides can increase the current density, significantly enhance the current efficiency of the system, thereby accelerating the reaction rate and shortening the reaction time.

[0044] Highly reactive free radicals or oxidizing species generated during electrochemical fluorination, if left uncontrolled, can cause the raw materials to polymerize into double-bonded intermediates, forming high-viscosity polymers that adhere to the electrode surface, reducing the effective reaction area. The relatively weak SH bonds in thiol compounds can effectively capture highly reactive free radicals, thereby quenching these reactive species that easily initiate polymerization side reaction pathways. Furthermore, the relatively short carbon chains in thiol compounds result in higher stability, reducing the occurrence of their own side reactions.

[0045] Perfluorobutyl sulfonyl fluoride (PFBS) is an electrochemical fluorination product with good tolerance in the reaction system. Its addition can stabilize and dilute the reaction solution, further reducing the probability of polymerization side reactions initiated by highly reactive free radicals or oxides, and reducing the formation of high-viscosity polymers. At the same time, PFBS has a similar structure to the target product, which can promote the timely removal of the target product from the electrode region and reduce product loss due to over-reaction.

[0046] In summary, alkali metal fluorides can improve current efficiency to accelerate the main reaction; thiols precisely suppress side reactions such as polymerization by quenching highly reactive free radicals; and perfluorobutylsulfonyl fluoride dilutes the reaction solution, stabilizes the environment, and promotes the removal of products from the electrode surface to avoid over-reaction. These three components synergistically construct a "highly efficient driving" system. Targeted conversion A virtuous cycle of "timely removal": alkali metal fluorides provide reaction kinetics, thiols ensure pathway selectivity, and perfluorobutylsulfonyl fluoride maintains electrode activity and protects the product, thus working together to efficiently and selectively convert reactants into the target product and significantly improve yield.

[0047] In some embodiments, the alkali metal fluoride includes at least one of potassium fluoride, lithium fluoride, sodium fluoride, and cesium fluoride. Exemplarily, the alkali metal oxide is selected from potassium fluoride, lithium fluoride, sodium fluoride, or cesium fluoride, or any two, three, or four of potassium fluoride, lithium fluoride, sodium fluoride, and cesium fluoride.

[0048] The alkali metal fluoride used in this application needs to be a substance soluble in anhydrous hydrogen fluoride and possessing electrolyte properties, which can increase the current density and thus shorten the reaction time. In some embodiments, the amount of alkali metal fluoride added is 1% to 2% of the mass of anhydrous hydrogen fluoride. Exemplarily, the amount of alkali metal fluoride added is 1%, 1.2%, 1.5%, 1.8%, 2% of the mass of anhydrous hydrogen fluoride, or any value between two of the above.

[0049] This implementation method can effectively improve the conductivity of the system, accelerate the reaction rate, further enhance the reaction efficiency and stability, ensure the smooth progress of the electrolysis process, and reduce the reaction stagnation problem caused by insufficient conductivity by controlling the type and amount of alkali metal fluorides added.

[0050] The thiol compounds in this application contain -SH functional groups. In some embodiments, the thiol compounds include at least one of ethanethiol, n-propanethiol, isopropanethiol, n-butanethiol, sec-butanethiol, and 1-hexanethiol. Exemplarily, the thiol compound is selected from n-propanethiol, isopropanethiol, n-butanethiol, sec-butanethiol, or 1-hexanethiol, or any two, three, or any combination of more of n-propanethiol, isopropanethiol, n-butanethiol, sec-butanethiol, and 1-hexanethiol. Optionally, the thiol compound includes at least one of n-butanethiol and sec-butanethiol.

[0051] In some embodiments, the amount of thiol compound added is 2% to 4% of the mass of anhydrous hydrogen fluoride. Exemplarily, the amount of thiol compound added is 2%, 2.5%, 3%, 3.5%, 4% of the mass of anhydrous hydrogen fluoride, or any value between two of the above.

[0052] This embodiment, by controlling the type and amount of thiol compounds, can effectively capture highly reactive free radicals, suppress polymerization side reactions, improve reaction selectivity, enhance system conductivity, help improve current efficiency, increase the yield of the target product, reduce polymer adhesion on the electrode surface, and extend electrode life.

[0053] In some embodiments, the amount of perfluorobutyl sulfonyl fluoride added is 2% to 4% of the mass of anhydrous hydrogen fluoride. Exemplarily, the amount of perfluorobutyl sulfonyl fluoride added is 2%, 2.5%, 3%, 3.5%, 4% of the mass of anhydrous hydrogen fluoride, or any value between two of the above.

[0054] This embodiment can stabilize and dilute the reaction solution by controlling the amount of perfluorobutyl sulfonyl fluoride added, thereby reducing the concentration of highly reactive free radicals and reducing the probability of side reactions. At the same time, based on the principle of like dissolves like, it promotes the product to leave the electrode area, avoids excessive product reaction and loss, improves product yield, and stabilizes the reaction system environment.

[0055] In some embodiments, the amount of butoxybutylsulfonyl fluoride added is 3% to 12% of the mass of anhydrous hydrogen fluoride, optionally 5% to 10%. Exemplarily, the amount of butoxybutylsulfonyl fluoride added is 3%, 5%, 6%, 7%, 8%, 9%, 10%, 12% of the mass of anhydrous hydrogen fluoride, or any intermediate value between the above two values.

[0056] In some embodiments, alkali metal fluorides and perfluorobutyl sulfonyl fluoride are first added to the electrolytic cell for pre-electrolysis, and then thiol compounds and butoxybutyl sulfonyl fluoride are added for electrolysis reaction.

[0057] This implementation method, by first pre-electrolyzing alkali metal fluorides and perfluorobutyl sulfonyl fluoride, and then adding thiols and butoxybutyl sulfonyl fluoride, can establish a stable electrochemical environment in advance, reduce side reactions, improve the stability and efficiency of the reaction system, lay the foundation for the smooth progress of the subsequent main reaction, and is conducive to continuous industrial production.

[0058] In some embodiments, the thiol compound and butoxybutylsulfonyl fluoride are premixed and then added to the electrolytic cell simultaneously.

[0059] This embodiment involves adding thiol compounds and butoxybutylsulfonyl fluoride after premixing, which can alleviate the exothermic phenomenon during feeding, avoid the increase of side reactions caused by excessively high local temperatures, and at the same time make the materials more uniformly mixed, improve the uniformity of the reaction, ensure that the reaction is carried out in a stable temperature environment, and improve the consistency of the product.

[0060] In some embodiments, the voltage applied during the electrolysis reaction is 4.5V to 5.0V. Exemplarily, the voltage applied during the electrolysis reaction is 4.5V, 4.6V, 4.7V, 4.8V, 4.9V, 5.0V, or any value between two of the above.

[0061] This implementation method controls the electrolysis voltage at 4.5V~5.0V, avoiding the side reaction of fluoride ions being oxidized to elemental fluorine, improving the safety and controllability of the reaction, while ensuring the high efficiency of the reaction, reducing power consumption, lowering production costs, and improving the economics of the reaction.

[0062] In some embodiments, the temperature during the electrolysis reaction is -3°C to 10°C, and can be selected as 0°C to 5°C. Exemplarily, the temperature during the electrolysis reaction is -3°C, 0°C, 1°C, 2°C, 3°C, 4°C, 5°C, 7°C, 10°C, or any intermediate value between two of the above values.

[0063] The temperature in this application refers to the controlled temperature of the electrolyte system during the electrolysis reaction.

[0064] This embodiment controls the reaction temperature between -3℃ and 10℃, optionally between 0℃ and 5℃, balancing reaction yield and reaction rate. It avoids carbon chain breakage side reactions caused by excessively high temperatures, and also avoids excessively slow reaction rates caused by excessively low temperatures, thus improving the overall efficiency of the reaction and ensuring that the reaction proceeds under optimal temperature conditions. Reaction temperatures below -3℃ lead to a significant decrease in current density, resulting in excessively long reaction times and reduced reaction efficiency; reaction temperatures above 10℃ exacerbate carbon chain breakage side reactions, reducing reaction yield. 0~5℃ is the preferred temperature range, balancing reaction yield and reaction rate.

[0065] In some embodiments, the electrolysis reaction causes the electrolyte in the electrolytic cell to change color to colorless; And / or, the electrolysis reaction time is 36h~72h.

[0066] This implementation method clarifies the criteria for determining the reaction endpoint, enabling accurate control of the reaction process, avoiding incomplete or excessive reactions, ensuring product yield and purity, achieving precise production control, improving production stability and controllability, and ensuring consistent product quality in each production run.

[0067] In some implementations, it includes the following steps: S1. Add anhydrous hydrogen fluoride to the electrolytic cell and apply a voltage of 3.5V~4.0V for pre-electrolysis to remove residual moisture. After the current drops to a level that does not change for 2 consecutive hours, stop the power supply. S2. Add alkali metal fluoride and perfluorobutyl sulfonyl fluoride to the electrolytic cell, apply a voltage of 4.5V~5.0V for pre-electrolysis, and stop the power supply after the current rises to a level that no longer changes for 2 hours. S3. Add butoxybutylsulfonyl fluoride and thiol compounds to the electrolytic cell, apply a voltage of 4.5V~5.0V, and carry out the electrolysis reaction at a temperature of -3℃~10℃.

[0068] This implementation method effectively removes residual moisture from the system through a two-step pre-electrolysis process, creating a stable electrochemical environment in advance. This lays the foundation for the smooth progress of the subsequent main reaction, further improving the stability of the reaction and the product yield, reducing side reactions caused by the presence of moisture, and enhancing the reliability of the reaction.

[0069] In some embodiments, the method further includes a step of purifying the crude product obtained from the electrolysis reaction; Optionally, the purification method includes: washing and drying the crude product, then performing vacuum distillation under a negative pressure of 0.01 MPa, and collecting the fraction at 88℃~92℃.

[0070] This implementation method, through specific purification steps, can effectively remove impurities from the crude product, obtain the target product with high purity, expand the application range of the compound, meet the needs of high-end application scenarios, and enhance the market competitiveness of the product.

[0071] As one embodiment, this application provides a method for preparing 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride using an electrochemical fluorination method, specifically including the following steps: (1) Add anhydrous hydrogen fluoride to the electrolytic cell and apply a voltage of 3.5~4.0V to pre-electrolyze and remove residual moisture. Stop the power supply after the current drops to a level that does not change for 2 consecutive hours.

[0072] (2) Add alkali metal fluoride with anhydrous hydrogen fluoride mass fraction of 1%~2% and perfluorobutyl sulfonyl fluoride with anhydrous hydrogen fluoride mass fraction of 2%~4% in sequence to the electrolytic cell, apply a voltage of 4.5V~5.0V for pre-electrolysis, and stop the power supply after the current rises to a level that no longer changes for 2 hours.

[0073] (3) Premix 5%~10% anhydrous hydrogen fluoride butoxybutylsulfonyl fluoride and 2%~4% anhydrous hydrogen fluoride thiol compounds, then add them to the electrolytic cell, apply a voltage of 4.5V~5.0V, and react at a temperature of 0℃~5℃. After the reaction continues for 36h~72h, the color of the electrolyte changes from dark purple to almost colorless. Then stop the power supply and discharge the material from the bottom of the electrolytic cell to obtain the crude product.

[0074] (4) After washing and drying the crude product with an aqueous solution of potassium hydroxide with a mass concentration of 8%~12%, it is subjected to vacuum distillation under a negative pressure of 0.01 MPa. After removing the fraction at <65℃, the fraction at 88℃~92℃ is collected, which is the target product 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride.

[0075] This implementation method involves adding the raw materials in steps: first, alkali metal fluorides and perfluorobutylsulfonyl fluoride are added for pre-electrolysis, and then thiols and butoxybutylsulfonyl fluoride are added after pre-mixing. Specifically, in terms of solubility, the reactant butoxybutylsulfonyl fluoride and thiols are miscible in any proportion, but both are insoluble in alkali metal fluorides and perfluorobutylsulfonyl fluoride. Furthermore, alkali metal fluorides are usually solids, while other materials are liquids; prioritizing the addition of alkali metal fluorides before adding other liquid materials minimizes residue buildup. In addition, when the reactant butoxybutylsulfonyl fluoride and thiols are added alone or in combination, the electrolyte exhibits significant exothermic activity; however, no exothermic activity occurs when alkali metal fluorides and perfluorobutylsulfonyl fluoride are added. Moreover, when perfluorobutylsulfonyl fluoride is added first, followed by the mixture of reactant butoxybutylsulfonyl fluoride and thiols, the exothermic phenomenon is somewhat mitigated. Considering the above, this order of addition helps maintain the stability of the reaction conditions.

[0076] Furthermore, the addition of functional additives and the electrochemical fluorination process parameters in this application interact with each other. By adding the aforementioned functional additives, the reaction system can operate stably at a lower reactant concentration (5%~10%), which helps reduce side reactions from the source and also increases the actual reaction efficiency. The conversion of 5%~10% reactant requires only 36h~72h; while the traditional reaction system without functional additives requires a higher reactant concentration (approximately 15%), and the conversion of 15% reactant requires 168h. In addition, the reaction voltage in this application is reduced from the traditional voltage parameter of 6.0V~6.6V to 4.5V~5.0V, and the reaction temperature is reduced from the traditional temperature parameter of 15℃~19℃ to -3℃~10℃. Under relatively milder conditions and with the synergistic effect of the aforementioned additives, polymerization side reactions are effectively suppressed, and the reaction pathway is significantly changed. The yield of the target product in this application is significantly increased from the traditional yield of 0.5%~1.5% to 15%~25%, while also significantly improving the utilization rate of electrical and thermal energy, making it more economical.

[0077] In this application, product yield refers to the percentage of the number of moles of the target product relative to the number of moles of the reactant butoxybutylsulfonyl fluoride.

[0078] In addition, this application provides a perfluoro-4-butoxy-1-butylsulfonyl fluoride, which is prepared by the method described in the previous embodiment for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride.

[0079] The perfluoro-4-butoxy-1-butylsulfonyl fluoride prepared by the above method has high purity, high yield, and stable quality, which can meet the needs of subsequent applications, promote the widespread use of this compound, and provide a high-quality intermediate for the development of PFOS alternatives.

[0080] This application provides an application of the perfluoro-4-butoxy-1-butylsulfonyl fluoride described in the foregoing embodiments, wherein the perfluoro-4-butoxy-1-butylsulfonyl fluoride is used to derivatize potassium perfluoro-4-butoxy-1-butanesulfonate. Specifically, potassium 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride is a fluorocarbon surfactant that can be synthesized from it.

[0081] This application derives the perfluoro-4-butoxy-1-butylsulfonyl fluoride into potassium perfluoro-4-butoxy-1-butanesulfonate, which yields a superior PFOS substitute with higher surface activity and lower toxicity. It can be widely used in surfactants, chromium mist inhibitors, and other fields, fully leveraging the application value of this compound and providing a more environmentally friendly and efficient product for the chemical industry.

[0082] The features and performance of this application will be further described in detail below with reference to the embodiments.

[0083] Example 1 This embodiment provides a 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride, the preparation process of which is as follows: (1) Add anhydrous hydrogen fluoride to the electrolytic cell and apply a voltage of 3.5V to pre-electrolyze and remove residual moisture. Stop the power supply after the current drops to a level that does not change for 2 consecutive hours.

[0084] (2) Add potassium fluoride (KF) with anhydrous hydrogen fluoride at a mass fraction of 1% and perfluorobutyl sulfonyl fluoride (PFBS) with anhydrous hydrogen fluoride at a mass fraction of 3% in sequence to the electrolytic cell. Apply a voltage of 4.8V for pre-electrolysis. After the current rises to a level that does not change for 2 consecutive hours, stop the power supply.

[0085] (3) Premix 8% butoxybutyryl fluoride and 3% n-butanethiol (1-Butanethiol) of anhydrous hydrogen fluoride, add them to the electrolytic cell, apply a voltage of 4.8V, and react at 3°C. After reacting for 65 hours, the color of the electrolyte changes from dark purple to almost colorless. Stop the power supply and discharge the crude product from the bottom of the electrolytic cell.

[0086] (4) The crude product was washed and dried with a 10% potassium hydroxide aqueous solution and then subjected to vacuum distillation at a negative pressure of 0.01 MPa. After removing the fraction below 65°C, the fraction at 88°C to 92°C was collected, which was the target product 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride. The yield of the target product was 23%.

[0087] Example 2 The difference between this embodiment and Example 1 is that: 2% potassium fluoride by mass of anhydrous hydrogen fluoride was added, and after continuous reaction for 56 hours, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 22%.

[0088] Example 3 The difference between this embodiment and Example 1 is that: 3% potassium fluoride of anhydrous hydrogen fluoride was added; after 58 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 21%.

[0089] Example 4 The difference between this embodiment and Example 1 is that 2% n-butanethiol by mass of anhydrous hydrogen fluoride was added; after 68 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 20%.

[0090] Example 5 The difference between this embodiment and Example 1 is that 4% n-butanethiol (by mass fraction of anhydrous hydrogen fluoride) was added; after 64 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 22%.

[0091] Example 6 The difference between this embodiment and Example 1 is that 5% n-butanethiol (by mass fraction of anhydrous hydrogen fluoride) was added; after 60 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 15%.

[0092] Example 7 The difference between this embodiment and Example 1 is that: 2% by mass of anhydrous hydrogen fluoride perfluorobutyl sulfonyl fluoride was added; after 66 hours of continuous reaction, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 18%.

[0093] Example 8 The difference between this embodiment and Example 1 is that: 4% by mass of anhydrous hydrogen fluoride perfluorobutyl sulfonyl fluoride was added; after 59 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 24%.

[0094] Example 9 The difference between this embodiment and Example 1 is that: 1% by mass of anhydrous hydrogen fluoride perfluorobutyl sulfonyl fluoride was added; after 68 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 12%.

[0095] Example 10 The difference between this embodiment and Example 1 is that: 2% by mass of anhydrous hydrogen fluoride n-butanethiol was added; 2% by mass of anhydrous hydrogen fluoride perfluorobutylsulfonyl fluoride was added; after continuous reaction for 67 hours, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 23%.

[0096] Example 11 The difference between this embodiment and Example 1 is as follows: 2% potassium fluoride was added by mass of anhydrous hydrogen fluoride; 4% n-butanethiol was added by mass of anhydrous hydrogen fluoride; 4% perfluorobutyl sulfonyl fluoride was added by mass of anhydrous hydrogen fluoride; after continuous reaction for 60 hours, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 21%.

[0097] Example 12 The difference between this embodiment and Example 1 is that: 5% by mass of anhydrous hydrogen fluoride butoxybutylsulfonyl fluoride was added; after 48 hours of continuous reaction, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 24%.

[0098] Example 13 The difference between this embodiment and Example 1 is that: 10% by mass of anhydrous hydrogen fluoride butoxybutylsulfonyl fluoride was added; after a continuous reaction of 71 h, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 19%.

[0099] Example 14 The difference between this embodiment and Example 1 is that: 3% by mass of anhydrous hydrogen fluoride butoxybutylsulfonyl fluoride was added; after 40 hours of continuous reaction, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 16%.

[0100] Example 15 The difference between this embodiment and Example 1 is that: 12% by mass of anhydrous hydrogen fluoride butoxybutylsulfonyl fluoride was added; after a continuous reaction of 93 h, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 16%.

[0101] Example 16 The difference between this embodiment and Example 1 is that sodium fluoride with anhydrous hydrogen fluoride at a mass fraction of 1% was added to replace potassium fluoride as a functional additive; after continuous reaction for 96 hours, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 18%.

[0102] Example 17 The difference between this embodiment and Example 1 is that cesium fluoride with a mass fraction of 1% anhydrous hydrogen fluoride was added to replace potassium fluoride as a functional additive; after continuous reaction for 88 hours, the color of the electrolyte changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 16%.

[0103] Example 18 The difference between this embodiment and Example 1 is that 3% (by mass) of anhydrous hydrogen fluoride ethanethiol was added to replace n-butanethiol as a functional additive; after continuous reaction for 84 hours, the electrolyte color changed from dark purple to almost colorless; finally, the target product was obtained with a yield of 11%.

[0104] Comparative Example 1 The difference between this comparative example and Example 1 is that no n-butanethiol or other thiol compounds were added; after 68 hours of continuous reaction, the electrolyte color changed from dark purple to almost colorless; and the target product was finally obtained with a yield of 4%.

[0105] Comparative Example 2 The difference between this comparative example and Example 1 is that: perfluorobutylsulfonyl fluoride was not added; after 70 hours of continuous reaction, the color of the electrolyte changed from dark purple to almost colorless; and the target product was finally obtained with a yield of 7%.

[0106] Comparative Example 3 The difference between this comparative example and Example 1 is that no potassium fluoride or other alkali metal fluorides were added; after a continuous reaction of 120 h, the color of the electrolyte changed from dark purple to almost colorless; and the target product was finally obtained with a yield of 9%.

[0107] Comparative Example 4 The difference between this comparative example and Example 1 is that: no potassium fluoride or other alkali metal fluorides were added; no n-butanethiol or other thiol compounds were added; no perfluorobutylsulfonyl fluoride was added; after continuous reaction for 140 h, the color of the electrolyte changed from dark purple to almost colorless; and the target product was finally obtained with a yield of 0.6%.

[0108] Comparative Example 5 The difference between this comparative example and Example 1 is that 3% (by mass) of anhydrous hydrogen fluoride isooctyl mercaptan is added to replace n-butanethiol as a functional additive; after continuous reaction for 78 hours, the electrolyte color changes from dark purple to almost colorless; finally, the target product is obtained with a yield of 3%.

[0109] Based on the above Examples 1-18 and Comparative Examples 1-5 and the results, it can be concluded that: According to Examples 1-18, butoxybutylsulfonyl fluoride and functional additives: alkali metal fluoride, thiol compounds (carbon chain length of C2-C6) and perfluorobutylsulfonyl fluoride were used to prepare the target product 1,1,2,2,3,3,4,4-octafluoro-4-(perfluorobutoxy)butane-1-sulfonyl fluoride by electrochemical fluorination. Compared with Comparative Examples 1-5 without the above functional additives, the yield of the target product can be improved.

[0110] Among them, Comparative Examples 1 to 4 showed very low reaction efficiency and / or very low yield of target product when prepared without any functional additives or with only one or two functional additives. Therefore, it can be seen that the present application uses butoxybutylsulfonyl fluoride and three specific functional additives to prepare the product by electrochemical fluorination, which can achieve the synergistic effect between the additives.

[0111] As shown in Examples 1-3, based on the preparation method using butoxybutylsulfonyl fluoride and specific functional additives via electrochemical fluorination, the addition of alkali metal fluoride at a concentration of 1% to 3% of the mass of anhydrous hydrogen fluoride can improve reaction efficiency (manifested as a shortened reaction time) and significantly increase the yield of the target product. Optionally, adding 1% to 2% of the mass of anhydrous hydrogen fluoride can more significantly improve the yield of the target product. This is because the main function of alkali metal fluoride is to improve conductivity, thereby shortening the reaction time. However, while further increasing the amount of alkali metal fluoride will further shorten the reaction time, it will accelerate electrode corrosion, thereby increasing operating costs and affecting the product yield.

[0112] As shown in Examples 1, 4-6, based on the preparation using butoxybutylsulfonyl fluoride and specific functional additives via electrochemical fluorination, the addition of 2% to 5% of the mass of anhydrous hydrogen fluoride thiols can improve reaction efficiency and significantly increase the yield of the target product. Optionally, the addition of 2% to 4% of the mass of anhydrous hydrogen fluoride thiols can further significantly improve the yield of the target product. This is because thiols are hydrocarbons with a certain degree of conductivity (similar to the reaction raw materials of this application), and they undergo electrochemical fluorination reactions. Adding too much thiols may introduce more byproducts, thereby reducing the yield of the target product.

[0113] As shown in Examples 1 and 7-9, based on the preparation of perfluorobutylsulfonyl fluoride and specific functional additives according to the electrochemical fluorination method, the addition amount of perfluorobutylsulfonyl fluoride of 1% to 4% of the mass of anhydrous hydrogen fluoride can improve the reaction efficiency and the yield of the target product; optionally, the addition amount of perfluorobutylsulfonyl fluoride of 2% to 4% of the mass of anhydrous hydrogen fluoride can significantly improve the yield of the target product.

[0114] As can be seen from Examples 1, 10-11, based on the preparation of the product using butoxybutylsulfonyl fluoride and specific functional additives via electrochemical fluorination, changing the amount of functional additives may affect the yield of the target product.

[0115] As shown in Examples 1, 12-15, based on the preparation using butoxybutylsulfonyl fluoride and specific functional additives via electrochemical fluorination, the addition amount of butoxybutylsulfonyl fluoride is 3% to 12% of the mass of anhydrous hydrogen fluoride, which can significantly improve the yield of the target product. Optionally, the addition amount of butoxybutylsulfonyl fluoride is 5% to 10% of the mass of anhydrous hydrogen fluoride, which can more significantly improve the yield of the target product.

[0116] As shown in Examples 1, 16-17, based on the preparation of the target product by electrochemical fluorination using butoxybutylsulfonyl fluoride and specific functional additives, the selection of potassium fluoride, sodium fluoride, and cesium fluoride as alkali metal fluorides can significantly improve the yield of the target product.

[0117] As shown in Examples 1 and 18, using thiols (ethanethiol and butanethiol) with carbon chain lengths of C2 to C4 as functional additives can improve the yield of the target product. However, in Comparative Example 5, when using thiols (octylthiol) with a carbon chain length of C8 as a functional additive, the yield of the target product is very low, even lower than the yield when only one or two functional additives are used. This is because thiols are hydrocarbons with a certain degree of conductivity and undergo electrochemical fluorination reactions. The longer the carbon chain of the compound, the more side reactions occur in the electrochemical fluorination reaction. Octylthiol has a carbon chain length of C8 and relatively poor stability in the electrochemical fluorination reaction, thus easily undergoing side reactions and failing to effectively play its role as a functional additive.

[0118] In summary, the perfluoro-4-butoxy-1-butylsulfonyl fluoride, its preparation method, and its application in the embodiments of this application can improve the yield of the target product.

[0119] The above description is merely an embodiment of this application and is not intended to limit the scope of protection of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride, characterized in that, It includes the following steps: Butoxybutylsulfonyl fluoride and functional additives are added to an electrolytic cell containing anhydrous hydrogen fluoride for electrolytic reaction. The functional additives include alkali metal fluorides, thiols, and perfluorobutylsulfonyl fluoride, and the carbon chain length of the thiols is C2~C6.

2. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 1, characterized in that, The alkali metal fluoride includes at least one of potassium fluoride, lithium fluoride, sodium fluoride, and cesium fluoride; And / or, the amount of the alkali metal fluoride added is 1% to 2% of the mass of the anhydrous hydrogen fluoride.

3. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 1, characterized in that, The thiol compounds include at least one of ethanethiol, n-propanethiol, isopropanethiol, n-butanethiol, sec-butanethiol, and 1-hexanethiol; And / or, the amount of the thiol compound added is 2% to 4% of the mass of the anhydrous hydrogen fluoride.

4. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 1, characterized in that, The amount of perfluorobutyl sulfonyl fluoride added is 2% to 4% of the mass of the anhydrous hydrogen fluoride.

5. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 1, characterized in that, The amount of butoxybutylsulfonyl fluoride added is 3% to 12% of the mass of the anhydrous hydrogen fluoride, and can be selected as 5% to 10%.

6. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to any one of claims 1 to 5, characterized in that, First, the alkali metal fluoride and the perfluorobutyl sulfonyl fluoride are simultaneously added to the electrolytic cell for pre-electrolysis, and then the thiol compound and the butoxybutyl sulfonyl fluoride are added for electrolytic reaction.

7. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 6, characterized in that, The thiol compound and the butoxybutylsulfonyl fluoride are first premixed and then simultaneously added to the electrolytic cell.

8. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to any one of claims 1 to 5, characterized in that, The voltage applied during the electrolysis reaction is 4.5V~5.0V.

9. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to any one of claims 1 to 5, characterized in that, The temperature during the electrolysis reaction is -3℃ to 10℃, and can be selected as 0℃ to 5℃.

10. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to any one of claims 1 to 5, characterized in that, The electrolysis reaction occurs until the color of the electrolyte in the electrolytic cell changes to colorless; And / or, the electrolysis reaction takes 36h to 72h.

11. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 1, characterized in that, It includes the following steps: S1. Add anhydrous hydrogen fluoride to the electrolytic cell and apply a voltage of 3.5V~4.0V for pre-electrolysis to remove residual moisture. After the current drops to a level that does not change for 2 consecutive hours, stop the power supply. S2. Add the alkali metal fluoride and the perfluorobutyl sulfonyl fluoride to the electrolytic cell, apply a voltage of 4.5V~5.0V for pre-electrolysis, and stop the power supply after the current rises to a level that no longer changes for 2 hours. S3. Add the butoxybutylsulfonyl fluoride and the thiol compound to the electrolytic cell, and apply a voltage of 4.5V~5.0V to carry out the electrolysis reaction.

12. The method for preparing perfluoro-4-butoxy-1-butylsulfonyl fluoride according to claim 1 or 11, characterized in that, It also includes the step of purifying the crude product obtained from the electrolysis reaction; Optionally, the purification method includes: washing and drying the crude product, then performing vacuum distillation under a negative pressure of 0.01 MPa, and collecting the fraction at 88°C to 92°C.

13. A perfluoro-4-butoxy-1-butylsulfonyl fluoride, characterized in that, It is prepared by the method described in any one of claims 1 to 12 for perfluoro-4-butoxy-1-butylsulfonyl fluoride.

14. An application of the perfluoro-4-butoxy-1-butylsulfonyl fluoride as described in claim 13, characterized in that, The perfluoro-4-butoxy-1-butylsulfonyl fluoride is used to derive potassium perfluoro-4-butoxy-1-butanesulfonate.