Preparation method of sodium fluorosulfonate

Abstract

This invention discloses a method for preparing sodium fluorosulfonate, comprising reacting a fluorine source, a sodium source, and a sulfonic acid source, wherein the sulfonic acid source is sulfur trioxide. The raw materials used in this method are readily available, the preparation method is simple, and it can significantly improve the yield of the product, sodium fluorosulfonate.

Description

Technical Field

[0001] This invention relates to the field of chemical preparation technology, and more specifically, to a method for preparing sodium fluorosulfonate. Background Technology

[0002] With the booming development of electric vehicles powered by lithium-ion batteries, the application of lithium-ion batteries has expanded from portable electronic products to all aspects of social development. Limited lithium resources have restricted the vigorous development of lithium-ion batteries. Sodium and lithium are metallic elements in the same group but different periods, with similar chemical properties and very broad application prospects. It is expected that sodium can be used to replace lithium.

[0003] Current research on sodium-ion batteries is relatively mature. However, due to the need to improve their cycle performance, current research mainly focuses on the design and modification of positive and negative electrode materials, with less research on electrolytes. The electrolyte is a crucial component of the battery and has a significant impact on its performance.

[0004] Sodium fluorosulfonate can be used as a major component of sodium-ion battery electrolytes, but there are few reports on the synthesis of sodium fluorosulfonate. Existing methods for synthesizing sodium fluorosulfonate have too low a yield, which is not conducive to the utilization of raw materials and cost reduction.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of this invention is to provide a method for preparing sodium fluorosulfonate, thereby improving the yield of sodium fluorosulfonate.

[0007] This invention is implemented as follows: In a first aspect, the present invention provides a method for preparing sodium fluorosulfonate, comprising reacting a fluorine source, a sodium source and a sulfonic acid source, wherein the sulfonic acid source is sulfur trioxide.

[0008] In an optional embodiment, the sodium source is selected from at least one of sodium halide, sodium organic acid, sodium inorganic acid, metallic sodium, and sodium hydride; Preferably, sodium fluoride is used as both the fluorine source and the sodium source.

[0009] In an optional embodiment, the molar ratio of fluorine in the fluorine source, sodium in the sodium source, and sulfur trioxide is (0.9-1.1):(0.9-1.1):1.

[0010] In an optional embodiment, the reaction is carried out under non-aqueous solvent conditions; Preferably, the non-aqueous solvent is an aprotic solvent; Preferably, the non-aqueous solvent is at least one of dimethyl carbonate and propylene carbonate; Preferably, the non-aqueous solvent is dimethyl carbonate; Preferably, the ratio of the total mass of the reactants to the amount of the non-aqueous solvent added is 1:(4-10)g / ml.

[0011] In an optional embodiment, the reaction is carried out under catalytic conditions, wherein the catalyst is sodium bifluoride; Preferably, the amount of sodium bifluoride added is 8%-10% of the mass of sodium fluoride.

[0012] In an optional embodiment, the reaction temperature is 60℃-80℃ and the reaction time is 8h-12h.

[0013] In an optional embodiment, after the reaction is complete, the product is concentrated to obtain a crude product, which is then purified to obtain sodium fluosulfonate. Preferably, the temperature of the concentration step is 55℃-70℃.

[0014] In an optional embodiment, the crude product is mixed and dissolved with an organic solvent to obtain an organic solution, the organic solution is placed at (-8)-(-10)℃ and left to stand for 8h-12h, and then solid-liquid separation is performed to obtain a solid material containing sodium fluorosulfonate; In an optional embodiment, the ratio of the crude product to the organic solvent is 1:(18-22) g / ml; Preferably, the dissolution temperature is 60℃-80℃; Preferably, the obtained solid material is dried to obtain sodium fluorosulfonate; Preferably, the organic solvent is at least one of methanol and ethanol.

[0015] In an optional embodiment, the reaction process and / or purification step are carried out under an inert atmosphere.

[0016] The present invention has the following beneficial effects: Sodium fluorosulfonate can be prepared by reacting sulfur trioxide with sodium and fluorine sources. The raw materials are readily available, the preparation method is simple, and the yield of sodium fluorosulfonate can be significantly improved. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 The image shows the PXRD pattern of sodium fluofenzene. Figure 2 This is the fluorine spectrum of sodium fluorosulfonate. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention 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.

[0020] This application provides a method for preparing sodium fluorosulfonate, comprising reacting a fluorine source, a sodium source and a sulfonic acid source, wherein the sulfonic acid source is sulfur trioxide.

[0021] Sodium fluorosulfonate can be prepared by reacting sulfur trioxide with sodium and fluorine sources. The raw materials are readily available, the preparation method is simple, and the yield of sodium fluorosulfonate can be significantly improved.

[0022] The sulfur trioxide in this embodiment can be obtained by heating fuming sulfuric acid or by other methods. It should be noted that, in this embodiment, due to the presence of a fluorine source, corrosive components such as HF may be generated as byproducts. Therefore, the reaction vessel needs to be resistant to HF corrosion; specifically, a polytetrafluoroethylene (PTFE) reaction flask can be selected, and ordinary glass reaction flasks cannot be used.

[0023] In an optional embodiment, the sodium source is selected from at least one of sodium halide, sodium organic acid, sodium inorganic acid, metallic sodium, and sodium hydride; Preferably, sodium fluoride is used as both the fluorine source and the sodium source.

[0024] Sodium fluoride contains both sodium and fluorine, but no other elements, so it does not introduce impurities, which helps to improve the utilization rate of raw materials and facilitates the subsequent separation and purification of sodium fluorosulfonate.

[0025] The reaction principle of sodium fluoride reacting with sulfur trioxide to produce sodium fluorosulfonate is as follows:

[0026] In an optional embodiment, the molar ratio of fluorine in the fluorine source, sodium in the sodium source, and sulfur trioxide is (0.9-1.1):(0.9-1.1):1. When sodium fluoride is used as both the fluorine and sodium source, the molar ratio of sodium fluoride to sulfur trioxide is (0.9-1.1):1.

[0027] A slight excess of sulfur trioxide can improve the utilization rate of sodium fluoride and the product yield. If the ratio is lower than the above-mentioned range, more unreacted SO3 will remain, leading to an increase in the amount of organic solvent used for cleaning and a corresponding increase in cost. If the ratio is higher than the above-mentioned range, unreacted sodium source will remain, tending to reduce the purity of sodium fluorosulfonate. Specifically, the molar ratio of sodium fluoride to sulfur trioxide can be 0.90:1, 0.95:1, 1.00:1, 1.05:1, 1.10:1, etc.

[0028] In an optional embodiment, the reaction is carried out under non-aqueous solvent conditions; Preferably, the non-aqueous solvent is an aprotic solvent; Preferably, the non-aqueous solvent is at least one of dimethyl carbonate and propylene carbonate; Preferably, the non-aqueous solvent is dimethyl carbonate; Preferably, the ratio of the total mass of the reactants to the amount of the non-aqueous solvent added is 1:(4-10) g / ml, specifically any value between 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10 g / ml or 1:(4-10) g / ml.

[0029] In this embodiment, on the one hand, the reaction between sulfur trioxide and sodium fluoride is quite vigorous and may pose a safety hazard. Therefore, a solvent is introduced into the reaction system to reduce the intensity of the reaction and improve its controllability and safety. On the other hand, sodium fluorosulfonate has low solubility in solvents. If the amount of solvent used is too small, as sodium fluorosulfonate is generated, some of the sodium fluorosulfonate that cannot be dissolved in the solvent will adhere to the surface of sodium fluoride, preventing sodium fluoride from reacting with sulfur trioxide dissolved in the solvent. Therefore, the amount of solvent used needs to be sufficient to dissolve the product sodium fluorosulfonate.

[0030] It should be noted that if safety is not a concern, the solvent may be omitted.

[0031] In an optional embodiment, the reaction is carried out under catalytic conditions, wherein the catalyst is sodium bifluoride; Preferably, the amount of sodium bifluoride added is 8%-10% of the mass of sodium fluoride, specifically it can be any value between 8%, 8.5%, 9%, 9.5%, 10%, or 8%-10%.

[0032] In this embodiment, a large amount of solvent is added to dissolve sodium fluorosulfonate, thus significantly reducing the reaction rate. Fluorosulfonic acid, acting as a catalyst, can generate fluorosulfonic acid in the system. Fluorosulfonic acid reacts rapidly with the fluorine source, thereby increasing the reaction rate. However, the presence of sodium bifluoride has little effect on the yield of sodium fluorosulfonate.

[0033] In an optional embodiment, the reaction temperature is 60℃-80℃, and the reaction time is 8h-12h to ensure complete reaction. Specifically, the reaction temperature can be any value between 60℃, 65℃, 70℃, 75℃, 80℃, or 60℃-80℃; the reaction time can be any value between 8h, 9h, 10h, 11h, 12h, or 8h-12h.

[0034] It should be noted that there are no special requirements regarding the reaction feeding method and the order of addition. However, considering the ease of adjusting the quality of sulfur trioxide and the reaction temperature, the preferred feeding method is to add sulfur trioxide and the reaction solvent into the reaction vessel, followed by the addition of sodium fluoride and sodium hydrogen fluoride.

[0035] In an optional embodiment, after the reaction is complete, the product is concentrated to obtain a crude product, which is then purified to obtain sodium fluosulfonate. Preferably, the temperature of the concentration step is 55℃-70℃.

[0036] The purpose of concentration is to remove solvents from wastewater, and the specific temperature depends on the boiling point of the non-aqueous solvent. In some embodiments, concentration is carried out in a vacuum drying oven at a drying temperature of 55°C-70°C and a vacuum degree of 0.8-0.9 MPa. Drying under vacuum conditions improves drying efficiency.

[0037] In an optional embodiment, the crude product is mixed and dissolved with an organic solvent to obtain an organic solution, the organic solution is placed at (-8)℃-(-10)℃ and left to stand for 8h-12h, and then solid-liquid separation is performed to obtain a solid material containing sodium fluorosulfonate.

[0038] At low temperatures, the solubility of sodium fluorosulfonate in organic solvents decreases, causing it to precipitate continuously, resulting in a relatively pure solid material containing a certain amount of organic solvent. Specifically, the precipitation temperature of sodium fluorosulfonate from the organic solution can be any value between -8℃, -8.5℃, -9℃, -9.5℃, -10℃, or -8℃--10℃, and the standing time can be any value between 8h, 9h, 10h, 11h, 12h, or 8h-12h.

[0039] In an optional embodiment, the ratio of the crude product to the organic solvent is 1:(18-22)g / ml, specifically any value between 1:18g / ml, 1:19g / ml, 1:20g / ml, 1:21g / ml, 1:22g / ml or 1:(18-22)g / ml; Preferably, the melting temperature is 60℃-80℃, specifically any value between 60℃, 65℃, 70℃, 75℃, 80℃ or 60℃-80℃; Preferably, the obtained solid material is dried to obtain sodium fluorosulfonate; Preferably, the organic solvent is at least one of methanol and ethanol.

[0040] The introduction of organic solvents serves two purposes: firstly, to ensure the complete dissolution of sodium fluorosulfonate in solid materials, thereby removing impurities or residual wastewater solvents; therefore, the amount of organic solvent used should not be too small. Secondly, if the amount of organic solvent used is too large, more sodium fluorosulfonate will dissolve in the organic solvent, so the amount of organic solvent added needs to be set reasonably.

[0041] In an optional embodiment, the reaction process and / or purification step are carried out under an inert atmosphere.

[0042] Specifically, the inert atmosphere can be nitrogen or argon, the main purpose of which is to prevent the reaction system from coming into contact with moisture in the outside air.

[0043] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0044] Example 1 This embodiment provides a method for preparing sodium fluosulfonate, comprising the following steps: (1) Under nitrogen purging, 9.2 g (115 mmol) of sulfur trioxide was introduced into a polytetrafluoroethylene reaction flask. 60 ml of dimethyl carbonate was added to the reaction vessel, followed by 5.07 g (120.75 mmol) of sodium fluoride and 0.7129 g (11.5 mmol) of sodium hydrogen fluoride, i.e., the molar ratio of sodium fluoride to sulfur trioxide was 1.05:1. The reaction was carried out at 70 °C for 10 h. After the reaction, the product was directly concentrated to obtain 13.96 g of crude product.

[0045] (2) Under nitrogen protection, 500 ml of anhydrous ethanol was added to the crude product and the solid was completely dissolved at 70 °C. After stirring for about 30 min, the product was placed in a -18 °C refrigerator for 12 h to precipitate white crystals. After filtration, the residue was retained and dried to obtain 11.5 g of sodium fluorosulfonate (94.3 mmol, yield 82%, purity 99.8%).

[0046] The PXRD pattern of the sodium fluorosulfonate prepared in this embodiment is shown below. Figure 1 As shown in the figure, the three distinct diffraction peaks belong to sodium fluorosulfonate.

[0047] The fluorine spectrum of the sodium fluorosulfonate prepared in this embodiment is as follows: Figure 2 As shown, a single peak appears at a chemical shift of 40.5 ppm, which is attributed to the resonance absorption peak of fluorine atoms in sodium fluorosulfonate.

[0048] Example 2 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that the amount of sodium fluoride used is 126.5 mmol. That is, the molar ratio of sodium fluoride to sulfur trioxide is 1.1:1.

[0049] The results showed that the yield of sodium fluofenzene was 75% and the purity was 99.5%.

[0050] Example 3 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that the amount of sodium fluoride used is 103.5 mmol. That is, the molar ratio of sodium fluoride to sulfur trioxide is 0.9:1.

[0051] The results showed that the yield of sodium fluofenzene was 62%, and the purity was 99.6%.

[0052] Example 4 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that the reaction temperature in step (1) is 60°C.

[0053] The results showed that the yield of sodium fluofenzene was 48%, and the purity was 99.6%.

[0054] Example 5 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that the reaction temperature in step (1) is 80°C.

[0055] The results showed that the yield of sodium fluorosulfonate was 77%, and the purity was 99.5%.

[0056] Example 6 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that: the reaction temperature in step (1) is 70°C, the reaction time is 8h, and the amount of sodium fluoride used is 120.75mmol, that is: the molar ratio of sodium fluoride to sulfur trioxide is 1.05:1.

[0057] The results showed that the yield of sodium fluorosulfonate was 60%, and the purity was 99.6%.

[0058] Example 7 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that: the reaction temperature is 70°C, the reaction time is 12h, and the amount of sodium fluoride used is 120.75mmol, that is: the molar ratio of sodium fluoride to sulfur trioxide is 1.05:1.

[0059] The results showed that the yield of sodium fluofenzene was 68%, and the purity was 99.5%.

[0060] Example 8 This embodiment provides a method for preparing sodium fluorosulfonate, which differs from Example 1 only in that sodium hydrogen fluoride is not added.

[0061] The results showed that the yield of sodium fluofenzene was 65%, and the purity was 99.5%.

[0062] In summary, this invention provides a method for preparing sodium fluorosulfonate, using readily available and easily processed raw materials, and a simple method to produce sodium fluorosulfonate while significantly improving the yield of sodium fluorosulfonate. The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing sodium fluorosulfonate, characterized in that, The reaction involves using a fluorine source, a sodium source, and a sulfonic acid source, wherein the sulfonic acid source is sulfur trioxide, and sodium fluoride is used as both the fluorine source and the sodium source. The reaction was carried out under non-aqueous solvent conditions; The reaction is carried out under catalytic conditions, and the catalyst is sodium hydrogen fluoride.

2. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The molar ratio of fluorine in the fluorine source, sodium in the sodium source, and sulfur trioxide is (0.9-1.1):(0.9-1.1):

1.

3. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The non-aqueous solvent is an aprotic solvent.

4. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The non-aqueous solvent is at least one of dimethyl carbonate and propylene carbonate.

5. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The non-aqueous solvent is dimethyl carbonate.

6. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The ratio of the total mass of the reactants to the amount of the non-aqueous solvent added is 1:(4-10)g / ml.

7. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The amount of sodium bifluoride added is 8%-10% of the mass of sodium fluoride.

8. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, The reaction temperature is 60℃-80℃, and the reaction time is 8h-12h.

9. The method for preparing sodium fluorosulfonate according to claim 1, characterized in that, After the reaction is complete, the product is concentrated to obtain a crude product, which is then purified to obtain sodium fluorosulfonate.

10. The method for preparing sodium fluorosulfonate according to claim 9, characterized in that, The concentration step is performed at a temperature of 55℃-70℃.

11. The method for preparing sodium fluorosulfonate according to claim 9, characterized in that, The crude product is mixed and dissolved with an organic solvent to obtain an organic solution. The organic solution is placed at (-8)-(-10)℃ and left to stand for 8h-12h. Then, solid-liquid separation is performed to obtain a solid material containing sodium fluorosulfonate.

12. The method for preparing sodium fluorosulfonate according to claim 11, characterized in that, The ratio of the crude product to the organic solvent is 1:(18-22)g / ml.

13. The method for preparing sodium fluorosulfonate according to claim 12, characterized in that, The melting temperature is 60℃-80℃.

14. The method for preparing sodium fluorosulfonate according to claim 12, characterized in that, The obtained solid material is dried to obtain sodium fluorosulfonate.

15. The method for preparing sodium fluorosulfonate according to claim 12, characterized in that, The organic solvent is at least one of methanol and ethanol.

16. The method for preparing sodium fluorosulfonate according to claim 9, characterized in that, The reaction process and / or purification steps are carried out under an inert atmosphere.

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