A process for the synthesis of 1,3-propanedisulfonic acid difluoride

Abstract

This application relates to the field of synthesis technology of lithium-ion battery electrolyte additives, specifically to a synthesis process of 1,3-propanedisulfonyl fluoride. The synthesis process includes the following steps: S1. Adding 1,3-propanedisulfonyl chloride and potassium fluoride to a reaction vessel; S2. Adding distilled water as a reaction solvent to the reaction vessel and refluxing under stirring; S3. After the reaction solution has settled and separated into layers, separating and collecting the oil phase, adding toluene and activated carbon to the oil phase, and refluxing for decolorization; S4. Performing a first crystallization treatment on the decolorized solution, followed by filtration, and washing the filter cake obtained from the filtration; S5. Collecting the filtrate obtained after the first washing and performing a second crystallization treatment, followed by filtration again; S6. Vacuum drying the filter cake obtained in steps S4 and S5 to obtain 1,3-propanedisulfonyl fluoride. This application features mild reaction conditions, simple operation, low cost, and environmental friendliness.

Description

Technical Field

[0001] This application relates to the field of synthesis technology of lithium-ion battery electrolyte additives, specifically to a synthesis process of 1,3-propanedisulfonyl fluoride. Background Technology

[0002] 1,3-Propane disulfonyl fluoride, with the molecular formula C3H6F2O4S2, is a colorless liquid that is volatile at room temperature. Under high voltage, it effectively improves the oxidation resistance of the electrolyte, inhibits side reactions at the electrolyte-cathode interface, significantly enhances the interfacial stability between the two, and greatly mitigates problems such as rapid capacity decay under high-temperature cycling, exhibiting excellent battery characteristics.

[0003] Currently, the synthetic routes for 1,3-propanedisulfonyl fluoride mainly revolve around its key precursor, 1,3-propanedisulfonyl chloride, or its corresponding sulfonate. The core step in all these routes is the conversion of the sulfonyl chloride group or sulfonate group into a sulfonyl fluoride group. These can be broadly categorized into two types: direct fluorination and indirect fluorination.

[0004] Direct fluorination typically employs elemental fluorine, high-valence metal fluorides, or electrochemical fluorination to directly convert CH bonds or other functional groups into CF or SF bonds. These methods are highly reactive, but usually involve harsh reaction conditions, complex product distribution, and extremely demanding equipment requirements. While electrochemical fluorination is a mature technology, it is generally suitable for the preparation of perfluorinated compounds; for substrates containing active hydrogen, its yield and selectivity are often unsatisfactory.

[0005] The most common indirect fluorination method uses potassium fluoride as the fluorine source, carrying out a nucleophilic substitution reaction in an organic solvent system. However, existing technologies generally suffer from the following technical bottlenecks: First, the solvents used in traditional methods, such as ethylene glycol dimethyl ether and N,N-dimethylformamide, are not only expensive but also difficult to completely remove, resulting in low purity of the final product; second, side reactions are prone to occur during the reaction, especially when the reaction temperature is not properly controlled, which can lead to product decomposition or polymerization; third, the yield of existing processes is generally low, making it difficult to obtain high-purity products through simple post-processing.

[0006] For example, Chinese patent application publication number CN117720439A discloses a method for preparing 1,3-propanedisulfonyl fluoride. This method uses 1,3-dibromopropane and sodium sulfite as starting materials, and obtains sodium 1,3-propanedisulfonate through two steps of sulfonation and chlorination. Then, in the third step of fluorination, sodium 1,3-propanedisulfonate is reacted with potassium fluoride in acetonitrile solvent to prepare the target product, 1,3-propanedisulfonyl fluoride. This technical solution explicitly uses acetonitrile as the reaction medium for the fluorination step, which is a typical existing technology that utilizes aprotic polar organic solvents to promote the fluorination reaction. However, this technical solution has the following significant drawbacks: First, using acetonitrile as a solvent results in high processing costs and complex operation. Furthermore, to ensure an anhydrous environment in the reaction system, the entire process must be carried out under an inert atmosphere such as nitrogen or argon.

[0007] Secondly, acetonitrile is a flammable, explosive, and toxic chemical with a low flash point; its vapor can form an explosive mixture with air. The waste liquid produced after the reaction contains organic solvents, inorganic salts, and byproducts, and its composition is complex, making it difficult and costly to treat. Direct discharge of such waste liquid would cause serious environmental pollution.

[0008] Third, since 1,3-propanedisulfonyl fluoride has a high boiling point while acetonitrile has a relatively moderate boiling point, it is challenging to completely remove the solvent without causing product decomposition during the post-treatment process of vacuum distillation or recrystallization.

[0009] Besides solvent systems represented by acetonitrile, other aprotic polar solvents also present similar problems. For example, solvents such as DMF and DMSO have higher boiling points, making them more difficult to remove from the product, and they are prone to decomposition under high temperature and alkaline conditions, introducing more impurities. Although sulfolane has good thermal stability, it is expensive and has high viscosity, which is not conducive to mass transfer and post-processing.

[0010] In summary, existing methods for preparing 1,3-propanedisulfonyl fluoride are generally hampered by their dependence on demanding anhydrous organic solvent systems. This dependence directly leads to multiple drawbacks in the process, including high cost, cumbersome operation, significant safety and environmental pressures, and difficulty in balancing product yield and purity. These limitations restrict the widespread application and cost control of 1,3-propanedisulfonyl fluoride electrolyte additives.

[0011] Therefore, there is an urgent need to develop a process that is mild in reaction conditions, simple in operation, low in cost, environmentally friendly, and capable of preparing 1,3-propanedisulfonyl fluoride in high yield and high purity. Summary of the Invention

[0012] Existing methods for preparing 1,3-propanedisulfonyl fluoride are hampered by their dependence on harsh anhydrous organic solvent systems. This application proposes a process for preparing 1,3-propanedisulfonyl fluoride with mild reaction conditions, simple operation, low cost, environmental friendliness, and high yield and high purity.

[0013] The technical solution of this application is as follows: A process for synthesizing 1,3-propanedisulfonyl fluoride includes the following steps: S1. Add 1,3-propanedisulfonyl chloride and potassium fluoride to the reaction vessel; S2. Add distilled water as a reaction solvent to the reaction vessel and reflux the reaction under stirring; S3. After the reaction solution has settled and separated into layers, the oil phase is collected, toluene and activated carbon are added to the oil phase, and the solution is refluxed for decolorization. S4. Perform a first crystallization treatment on the decolorized liquid obtained after decolorization, then filter it, and wash the filter cake obtained by filtration. S5. Collect the filtrate obtained after the first crystallization treatment and perform a second crystallization treatment, followed by filtration to obtain a filter cake; S6. The filter cake obtained in steps S4 and S5 is dried under vacuum to obtain 1,3-propanedisulfonyl fluoride.

[0014] Preferably, the molar ratio of 1,3-propanedisulfonyl chloride to potassium fluoride in S1 is 1:2.0~2.3.

[0015] Preferably, the molar ratio of 1,3-propanedisulfonyl chloride to potassium fluoride in S1 is 1:2.1.

[0016] Preferably, the molar ratio of 1,3-propanedisulfonyl chloride to distilled water is 1:(9.8~11.1).

[0017] Preferably, the reflux reaction temperature in S2 is 60~100℃, and the reflux reaction time is 4~6 h.

[0018] Preferably, the reflux reaction temperature in S2 is 60°C, and the reflux reaction time is 5 h.

[0019] Preferably, the reflux decolorization time in S3 is 1.5~2 h, the decolorization temperature is 125℃, the mass-volume ratio of activated carbon to toluene is 1g:25mL, and the amount of activated carbon added is 10% of the theoretical mass of 1,3-propanedisulfonyl fluoride.

[0020] Preferably, the first crystallization treatment in S4 is carried out under stirring conditions at a temperature of -20°C for 40 minutes; the second crystallization treatment in S5 is carried out under stirring conditions at a temperature of -20°C for 20 minutes.

[0021] Preferably, the drying temperature in step S6 is 20°C and the vacuum degree is -0.085 MPa to -0.095 MPa.

[0022] Preferably, the purity of 1,3-propanedisulfonyl fluoride in S6 is ≥99.5%.

[0023] The beneficial effects of this application are as follows: This application is the first to use distilled water as a reaction solvent to achieve the fluorination reaction of 1,3-propanedisulfonyl chloride, breaking through the dependence of traditional processes on anhydrous organic solvents, strictly anhydrous operation, and inert gas protection. The operation is simple and significantly reduces equipment requirements and operational difficulty. By optimizing the raw material ratio and reaction conditions, the reaction can be completed under mild conditions of 60~100℃, with low energy consumption, high safety, and complete reaction conversion. Combined with the synergistic purification process of oil phase separation, toluene activated carbon reflux decolorization, 20℃ double stirring crystallization, and low-temperature vacuum drying, impurities can be efficiently removed, and the yield of the obtained product reaches 70%~80%, which is about 10% higher than the traditional acetonitrile system, with a purity of not less than 99.5%, which can meet the high purity requirements of lithium-ion battery electrolyte additives. At the same time, using water as the core solvent, the cost is low and the environment is environmentally friendly. The overall process is simple, the parameters are controllable, and the equipment compatibility is strong, showing excellent prospects for industrial scale-up and application. Attached Figure Description

[0024] Figure 1 The reaction equation diagram for the water system fluorination process provided by this invention; Figure 2 The 1,3-propanedisulfonyl fluoride prepared in Example 1 of this invention 1 1H NMR spectrum (deuterated reagent: CDCl3). Detailed Implementation

[0025] To further illustrate the technical means and effects of the present invention in achieving its intended purpose, the following detailed description of the specific implementation methods, structures, features, and effects of the present invention, in conjunction with the accompanying drawings and preferred embodiments, is provided below.

[0026] Example 1 This embodiment provides a synthesis process for 1,3-propanedisulfonyl fluoride, including the following steps: Fluorination of S1,1,3-propanedisulfonyl chloride: Add 18.00 g (0.075 mol) of 1,3-propanedisulfonyl chloride and 10.01 g (0.172 mol) of potassium fluoride to a two-necked flask equipped with a stirrer; S2. Then add 13.3 mL of distilled water, stir and heat to 80℃ for 4 h; S3. After the reaction is complete, allow the mixture to stand and separate into layers, and collect the oil phase. Add the oil phase, 1.55 g of activated carbon, and 40.0 mL of toluene to a two-necked flask equipped with a stirrer and a condenser. Heat the mixture to 125 °C and reflux for 1.5 h to remove the color. After the reaction is complete, filter the mixture in the flask while it is still hot to remove the activated carbon and collect the filtrate.

[0027] First crystallization of S4,1,3-propanedisulfonyl fluoride: The obtained filtrate was placed in a cooling circulating pump at -20°C for 40 min, with continuous stirring to allow the crystals to fully precipitate. Then, it was filtered and the filter cake was washed with n-hexane. The filter cake and filtrate were collected for later use.

[0028] S5.1,3-Propane disulfonyl fluoride second crystallization: The filtrate obtained in (4) was placed in a cooling circulating pump at -20°C for 20 min, and stirred continuously during the process to allow the crystals to fully precipitate. Then, it was filtered and the filter cake was collected.

[0029] S6. Drying of 1,3-propanedisulfonyl fluoride: The filter cakes of (4) and (5) were placed in a vacuum drying oven at a temperature of 20°C and the vacuum degree was -0.085 MPa to -0.095 MPa. Finally, 11.69 g of 1,3-propanedisulfonyl fluoride product was obtained, with a yield of 75.27% and a purity of 99.5%.

[0030] The prepared 1,3-propanedisulfonyl fluoride product was tested, and the results are as follows: Figure 2 As shown, the peak at 7.26 ppm in the spectrum is the solvent peak of deuterated chloroform (CDCl3), which is a normal background signal. Apart from the solvent peak, there are no obvious impurity peaks in the spectrum, and the main product peak is sharp with a stable baseline.

[0031] Example 2 This embodiment provides a synthesis process for 1,3-propanedisulfonyl fluoride, which differs from Example 1 in that: The amount of 1,3-propanedisulfonyl chloride used was 18.01 g, the amount of potassium fluoride used was 10.00 g, and the amount of distilled water used was 15.0 mL; the reaction temperature was 60℃, and the reaction time was 5 h.

[0032] The final product obtained was 1,3-propanedisulfonyl fluoride, with a yield of 79.14% and a purity of 99.7%.

[0033] Example 3 This embodiment provides a synthesis process for 1,3-propanedisulfonyl fluoride, which differs from Example 1 in that: The amount of 1,3-propanedisulfonyl chloride used was 9.01 g, potassium fluoride used was 5.00 g, and distilled water used was 6.7 mL; the reaction temperature was 60℃, and the reaction time was 5 h. The amount of activated carbon used was 0.78 g, the amount of toluene used was 20.0 mL, and the reaction was refluxed for 2 h for decolorization.

[0034] The final product obtained was 1,3-propanedisulfonyl fluoride, with a yield of 83.71% and a purity of 99.6%.

[0035] Example 4 This embodiment provides a synthesis process for 1,3-propanedisulfonyl fluoride, which differs from Example 1 in that: The amount of 1,3-propanedisulfonyl chloride used was 18.01 g, the amount of potassium fluoride used was 8.68 g, and the amount of distilled water used was 15.0 mL; the reaction temperature was 100℃, and the reaction time was 6 h.

[0036] The final product obtained was 1,3-propanedisulfonyl fluoride, with a yield of 78.12% and a purity of 99.6%.

[0037] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A process for synthesizing 1,3-propanedisulfonyl fluoride, characterized in that, Includes the following steps: S1. Add 1,3-propanedisulfonyl chloride and potassium fluoride to the reaction vessel; S2. Add distilled water as a reaction solvent to the reaction vessel and reflux the reaction under stirring; S3. After the reaction solution has settled and separated into layers, the oil phase is collected, toluene and activated carbon are added to the oil phase, and the solution is refluxed for decolorization. S4. Perform a first crystallization treatment on the decolorized liquid obtained after decolorization, then filter it, and wash the filter cake obtained by filtration. S5. Collect the filtrate obtained after the first crystallization treatment and perform a second crystallization treatment, followed by filtration to obtain a filter cake; S6. The filter cake obtained in steps S4 and S5 is dried under vacuum to obtain 1,3-propanedisulfonyl fluoride.

2. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The molar ratio of 1,3-propanedisulfonyl chloride to potassium fluoride in S1 is 1:2.0~2.

3.

3. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 2, characterized in that, The molar ratio of 1,3-propanedisulfonyl chloride to potassium fluoride in S1 is 1:2.

1.

4. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The molar ratio of 1,3-propanedisulfonyl chloride to distilled water is 1:(9.8~11.1).

5. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The reflux reaction temperature in S2 is 60~100℃, and the reflux reaction time is 4~6 h.

6. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 5, characterized in that, The reflux reaction in S2 is carried out at a temperature of 60°C for 5 hours.

7. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The reflux decolorization time in S3 is 1.5~2 h, and the decolorization temperature is 125℃; the mass-volume ratio of activated carbon to toluene is 1g:25mL, and the amount of activated carbon added is 10% of the theoretical mass of 1,3-propanedisulfonyl fluoride.

8. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The first crystallization treatment in S4 is carried out under stirring conditions at a temperature of -20°C for 40 min; the second crystallization treatment in S5 is carried out under stirring conditions at a temperature of -20°C for 20 min.

9. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The drying temperature in S6 is 20℃, and the vacuum degree is -0.085 MPa to -0.095 MPa.

10. The synthesis process of 1,3-propanedisulfonyl fluoride according to claim 1, characterized in that, The purity of 1,3-propanedisulfonyl fluoride in S6 is ≥99.5%.

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