Preparation method of azacyclo-bis (fluorosulfonyl) imide salt derivative
The method of synthesizing nitrogen heterocyclic bisfluorosulfonyl imide salts by one-pot synthesis and mixed solvent crystallization solves the problems of complex processes and low yields in existing technologies, and realizes the efficient and simplified preparation of nitrogen heterocyclic bisfluorosulfonyl imide salts, which are suitable for industrial applications.
Patent Information
- Application Number
- CN202411174634.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-26
- Publication Date
- 2026-03-03
AI Technical Summary
Existing synthetic routes for nitrogen-containing heterocyclic bisfluorosulfonyl imide salts are complex, cumbersome, and have low yields, making them unsuitable for industrial production.
A one-pot method was used to synthesize nitrogen heterocyclic bisfluorosulfonyl imide salts, which were then purified by a mixed solvent crystallization method. This simplified the operation and improved the purity. The specific steps included mixing the nitrogen heterocyclic compound, methylating agent, ethylating agent and bisfluorosulfonyl imide salt in a polar organic solvent, followed by vacuum drying to obtain the finished product.
It greatly simplifies the operation process, improves product yield and purity, and is suitable for industrial production.
Smart Images
Figure CN121591671A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of compound synthesis technology, specifically to the preparation of nitrogen-containing heterocyclic bisfluorosulfonyl imide salts. Background Technology
[0002] The development of next-generation energy devices such as batteries, fuel cells, and solar cells depends on the research and application of novel electrolyte materials. These materials can overcome the technical problems of current commercial electrolytes, such as safety and flammability. Ionic liquids and organic ionic plastic crystals are potential candidates for safe and durable electrolytes due to their high thermal stability and negligible vapor pressure. Recently, studies have found that nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivatives possess rapid ion transport, high electrochemical properties, thermal stability, non-volatility, and non-flammability. When combined with lithium or sodium salts, their ionic conductivity can be increased by several orders of magnitude. Furthermore, their flexible mechanical properties can minimize the problem of poor contact between the electrolyte and the electrode under volume expansion. Therefore, developing synthetic methods for nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivatives is of great significance and urgently needed.
[0003] Currently, there are few reported synthetic routes for nitrogen-containing heterocyclic bisfluorosulfonyl imide salts. For example, the literature "Ionic liquids and plastic crystals utilising the oxazolidinium cation: the effect of ether functionality in the ring" describes the preparation of a bromide intermediate by reflux reaction of 3-methyloxazolidine and bromoethane in ethyl acetate, followed by dissolution in water and dropwise addition to an aqueous solution of potassium bisfluorosulfonyl imide. The reaction is carried out overnight at room temperature, water is removed by vacuum evaporation, the product in the concentrate is dissolved in ethanol, filtered, the filtrate is concentrated to obtain a crude product, which is then washed with cold water overnight to precipitate a solid. This solid is filtered, the filter cake is dried under vacuum, washed again with pentane, and then dried under vacuum to obtain the final product, 3-methyl-3-ethyl-oxazolidine bisfluorosulfonyl imide. This preparation method involves many reaction steps, complex procedures, cumbersome operation, low product yield, and high costs for raw materials, equipment, and waste, making it unsuitable for industrial production. Summary of the Invention
[0004] The technical problem to be solved by the present invention is to provide a method for preparing nitrogen heterocyclic bisfluorosulfonyl imide salt derivatives, which has few preparation steps, high product yield and purity, and is suitable for industrial application.
[0005] To achieve the above objectives, the technical solution adopted by this invention is as follows: a method for preparing a nitrogen heterocyclic bis(fluorosulfonyl)imide salt derivative, comprising: 1. mixing a nitrogen heterocyclic compound, a methylating agent, an ethylating agent, a bis(fluorosulfonyl)imide salt, and an inorganic base in a polar organic solvent, heating, and after the reaction is complete, filtering to obtain a crude filtrate containing a nitrogen heterocyclic bis(fluorosulfonyl)imide salt; wherein the nitrogen heterocyclic compound is selected from one of oxazolidine, 4-cyanopiperidine, 4-fluoropiperidine, 4,4-difluoropiperidine, and 3-cyanopiperidine; and the bis(fluorosulfonyl)imide salt is selected from one of lithium bis(fluorosulfonyl)imide and potassium bis(fluorosulfonyl)imide; 2. adding an inert organic solvent to the crude filtrate for crystallization and vacuum drying to obtain the finished product.
[0006] Furthermore, in the aforementioned method for preparing a nitrogen-containing heterocyclic bisfluorosulfonyl imide salt derivative, the ethylating agent is selected from iodoethane and bromoethane.
[0007] Furthermore, in the aforementioned method for preparing a nitrogen-containing heterocyclic bisfluorosulfonyl imide salt derivative, the inorganic base is selected from sodium carbonate, potassium carbonate, and lithium carbonate.
[0008] Furthermore, in the aforementioned method for preparing a nitrogen heterocyclic bisfluorosulfonyl imide salt derivative, the polar organic solvent is selected from acetonitrile, tetrahydrofuran, ethyl acetate, and propylene carbonate; the mass ratio of the polar organic solvent to the nitrogen heterocyclic compound is 4 to 10.
[0009] Furthermore, in the aforementioned method for preparing a nitrogen-containing heterocyclic bisfluorosulfonyl imide salt derivative, the inert organic solvent is selected from one of n-hexane and toluene; the mass ratio of the inert organic solvent to the polar organic solvent is 1 to 3.
[0010] Furthermore, in the aforementioned method for preparing a nitrogen-containing heterocyclic bisfluorosulfonyl imide salt derivative, the inert organic solvent is selected from n-hexane and toluene.
[0011] Furthermore, in the aforementioned method for preparing a nitrogen heterocyclic bisfluorosulfonyl imide salt derivative, in the first step, the temperature is raised to 25℃~80℃.
[0012] Furthermore, in the aforementioned method for preparing a nitrogen-containing heterocyclic bisfluorosulfonyl imide salt derivative, the reaction time in the first step is controlled at 8-24 hours.
[0013] Furthermore, in the aforementioned method for preparing a nitrogen heterocyclic bisfluorosulfonyl imide salt derivative, the molar ratio of the nitrogen heterocyclic compound, methylating agent, ethylating agent, and bisfluorosulfonyl imide salt is 1:1:1:1.
[0014] Furthermore, in the aforementioned method for preparing a nitrogen heterocyclic bisfluorosulfonyl imide salt derivative, in the second step, the vacuum drying temperature is 70~120℃, the vacuum degree is 50~200Pa, and the drying time is 2~8h.
[0015] The advantages of this invention are: 1. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to this invention adopts a one-pot method to prepare the nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt, without the separation of intermediates, completing multiple reaction steps, greatly reducing the number of operation steps, greatly increasing the synthesis efficiency, greatly simplifying the process, and effectively reducing the preparation cost. 2. The nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative is purified by a mixed solvent crystallization method, resulting in high purity, low loss, and high crystallization yield. 3. It is suitable for industrial production. Instruction manual illustrations
[0016] Figure 1 This is the 1H NMR spectrum of the target product obtained in Example 1.
[0017] Figure 2 This is the carbon NMR spectrum of the target product obtained in Example 1.
[0018] Figure 3 This is the NMR fluorine spectrum of the target product obtained in Example 1. Detailed Implementation
[0019] The present invention will now be described in further detail with reference to preferred embodiments.
[0020] The preparation method of the nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative of the present invention is illustrated in the following reaction diagram: .
[0021] Example 1: 103 g of 4-fluoropiperidine, 90 g of dimethyl carbonate, 109 g of bromoethane, 187 g of lithium difluorosulfonylimide, 111 g of lithium carbonate, and 618 g of propylene carbonate were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 65°C and reacted for 12 hours, after which the reaction was stopped. The reaction solution was cooled to room temperature and filtered to obtain the reaction filtrate.
[0022] 1236g of toluene was added dropwise to the reaction filtrate and stirred to induce crystallization. The mixture was then filtered twice, and the filter cake was dried under vacuum at 120℃ and 50Pa for 2 hours to obtain 316g of 1-methyl-1-ethyl-4-fluoropiperidine difluorosulfonyl imine salt with a purity of 99.96%. The calculated molar yield was 96.93%.
[0023] See the product's 1H NMR spectrum. Figure 1 As shown, 1¹H NMR (400MHz, d-DMSO) δ 5.00–4.80 (¹H, m), 3.49–3.34 (⁶H, m), 3.04 (⁻¹H, s), 2.98 (¹H, s), 2.34–1.95 (⁻¹H, m), 1.30–1.15 (⁻¹H, m); see product ¹H NMR spectrum. Figure 2 As shown, 13 C NMR (100MHz, CDCl3) δ 84.95, 84.79, 83.25, 83.10, 60.96, 55.09, 55.04, 54.99, 54.73, 54.70, 54.51, 48.83, 43.70, 25.08, 24.93, 24.87, 24.72, 7.40, 7.13; fluorine NMR spectrum of the product is shown below. Figure 3 As shown, 19 F NMR (376MHz, d-DMSO) δ53.22, -182.08, -184.01.
[0024] Example 2: 73g of oxazolidine, 126g of dimethyl sulfate, 156g of iodoethane, 219g of potassium difluorosulfonamide, 265g of sodium carbonate, and 730g of acetonitrile were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 80°C and reacted for 8 hours, after which the reaction was stopped. The reaction solution was cooled to room temperature and filtered to obtain the reaction filtrate.
[0025] 2190g of n-hexane was added dropwise to the reaction filtrate and stirred to induce crystallization. The mixture was then filtered twice, and the filter cake was vacuum dried at 70℃ and 200Pa for 8 hours to obtain 278g of 3-methyl-3-ethyl-oxazole difluorosulfonyl imide with a purity of 99.56%. The calculated molar yield was 93.92%.
[0026] Example 3: 110g of 4-cyanopiperidine, 142g of iodomethane, 109g of bromoethane, 187g of lithium difluorosulfonylimide, 138g of potassium carbonate, and 440g of tetrahydrofuran were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 25°C and reacted for 24 hours before the reaction was stopped.
[0027] After cooling the reaction solution to room temperature, it was filtered. 440g of n-hexane was added dropwise to the filtrate and stirred to induce crystallization. The mixture was filtered a second time, and the filter cake was dried under vacuum at 80℃ and 100Pa for 4h to obtain 301g of 1-methyl-1-ethyl-4-cyanopiperidine difluorosulfonyl imine salt with a purity of 99.84%. The calculated molar yield was 90.39%.
[0028] Example 4: 121 g of 4,4-difluoropiperidine, 186 g of methyl p-toluenesulfonate, 109 g of bromoethane, 219 g of potassium difluorosulfonylimide, 148 g of lithium carbonate, and 605 g of ethyl acetate were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 70°C and reacted for 10 hours, after which the reaction was stopped. The reaction solution was cooled to room temperature and filtered to obtain the reaction filtrate.
[0029] 1210 g of n-hexane was added dropwise to the reaction filtrate and stirred to induce crystallization. The mixture was then filtered twice, and the filter cake was dried under vacuum at 110 °C and 150 Pa for 2.5 h to obtain 317 g of 1-methyl-1-ethyl-4,4-difluoropiperidine difluorosulfonyl imine salt with a purity of 99.67%. The calculated molar yield was 92.15%.
[0030] Example 5: 110g of 3-cyanopiperidine, 164g of methyl trifluoromethanesulfonate, 109g of bromoethane, 187g of lithium difluorosulfonylimide, 207g of potassium carbonate, and 880g of propylene carbonate were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 55°C and reacted for 20 hours, after which the reaction was stopped. The reaction solution was cooled to room temperature and filtered to obtain the reaction filtrate.
[0031] 1760g of toluene was added dropwise to the reaction filtrate and stirred to induce crystallization. The mixture was then filtered twice, and the filter cake was dried under vacuum at 120℃ and 68Pa for 3h to obtain 314g of 1-methyl-1-ethyl-3-cyanopiperidine difluorosulfonyl imine salt with a purity of 99.78%. The calculated molar yield was 94.29%.
[0032] Example 6: 103g of 4-fluoropiperidine, 164g of methyl trifluoromethanesulfonate, 156g of iodoethane, 219g of potassium difluorosulfonylimide, 159g of sodium carbonate, and 900g of acetonitrile were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 70°C and reacted for 16 hours, after which the reaction was stopped. The reaction solution was cooled to room temperature and filtered to obtain the reaction filtrate.
[0033] 1800g of toluene was added dropwise to the reaction filtrate and stirred to induce crystallization. The mixture was then filtered twice, and the filter cake was dried under vacuum at 100℃ and 95Pa for 4h to obtain 309g of 1-methyl-1-ethyl-4-fluoropiperidine difluorosulfonyl imine salt with a purity of 99.91%. The calculated molar yield was 94.79%.
[0034] Example 7: 103g of 4-fluoropiperidine, 90g of dimethyl carbonate, 109g of bromoethane, 187g of lithium difluorosulfonylimide, 138g of potassium carbonate, and 800g of ethyl acetate were added to a three-necked flask equipped with a thermometer, stirrer, and condenser. The mixture was heated to 70°C and reacted for 16 hours before the reaction was stopped.
[0035] After cooling the reaction solution to room temperature, it was filtered. 1200g of n-hexane was added dropwise to the filtrate and stirred to induce crystallization. The mixture was filtered a second time, and the filter cake was dried under vacuum at 75℃ and 160Pa for 6 hours to obtain 302g of 1-methyl-1-ethyl-4-fluoropiperidine difluorosulfonyl imine salt with a purity of 99.82%. The calculated molar yield was 92.64%.
[0036] Comparative Example 8: 87g of 3-methyloxazolidine and 435g of ethyl acetate were added to a three-necked flask equipped with a thermometer, stirrer and condenser. After heating to 40°C, 125g of bromoethane was added dropwise. After the addition was completed, the mixture was refluxed at 70°C overnight.
[0037] Remove the solvent and low-boiling point by vacuum distillation, add 475g of deionized water, stir to dissolve, and then add dropwise to a potassium difluorosulfonamide solution (185g of potassium difluorosulfonamide dissolved in 356g of deionized water) at 25°C. After the addition is complete, keep the temperature at 25°C and react overnight.
[0038] After the reaction was complete, the solvent was removed by vacuum evaporation, ethanol was added and stirred for 1 hour, then filtered and the filtrate was concentrated. Cold water was added to the concentrate and stirred overnight, then filtered, the filter cake was dried under vacuum, n-pentane was added, and after stirring and washing, it was dried under vacuum to obtain 202 g of 3-methyl-3-ethyl-oxazole difluorosulfonyl imide with a purity of 99.07%, and the calculated molar yield was 68.24%.
[0039] The experimental results of Comparative Example 8 show that other methods for synthesizing nitrogen heterocyclic bisfluorosulfonyl imide salts have disadvantages such as low yield, many by-products, and low product purity.
[0040] From Examples 1 to 7, we can conclude that: 1. The method for preparing a nitrogen-containing heterocyclic bisfluorosulfonyl imide salt according to the present invention employs a one-pot method, eliminating the need for intermediate separation, completing multiple reaction steps, reducing operational steps, significantly increasing synthesis efficiency, greatly simplifying the process, and effectively reducing preparation costs. 2. The nitrogen-containing heterocyclic bisfluorosulfonyl imide salt derivative is obtained by purification using a mixed solvent crystallization method, resulting in high purity, low loss, and high crystallization yield. In Examples 1 to 7, the yields are all above 90%, and the purity is above 99%. Therefore, this synthesis method is suitable for industrial production.
Claims
1. A method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative, characterized in that: I. A nitrogen heterocyclic compound, a methylating agent, an ethylating agent, a difluorosulfonyl imide salt, and an inorganic base are mixed in a polar organic solvent, heated, and after the reaction is complete, filtered to obtain a crude filtrate containing a nitrogen heterocyclic difluorosulfonyl imide salt; wherein the nitrogen heterocyclic compound is selected from one of oxazolidine, 4-cyanopiperidine, 4-fluoropiperidine, 4,4-difluoropiperidine, and 3-cyanopiperidine; and the difluorosulfonyl imide salt is selected from one of lithium difluorosulfonyl imide and potassium difluorosulfonyl imide; II. An inert organic solvent is added to the crude filtrate to crystallize, and vacuum drying is performed to obtain the finished product.
2. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: The ethylating agent is selected from iodoethane and bromoethane.
3. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: The inorganic base is selected from sodium carbonate, potassium carbonate, and lithium carbonate.
4. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: The polar organic solvent is selected from one of acetonitrile, tetrahydrofuran, ethyl acetate, and propylene carbonate; the mass ratio of the polar organic solvent to the nitrogen heterocyclic compound is 4 to 10.
5. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 4, characterized in that: The inert organic solvent is selected from hexane and toluene; the mass ratio of the inert organic solvent to the polar organic solvent is 1 to 3.
6. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: The inert organic solvent is selected from hexane and toluene.
7. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: In the first step, the temperature is raised to 25℃~80℃.
8. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: In the first step, the reaction time is controlled between 8 and 24 hours.
9. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: The molar ratio of nitrogen heterocyclic compound, methylating agent, ethylating agent, and difluorosulfonyl imide salt is 1:1:1:
1.
10. The method for preparing a nitrogen-containing heterocyclic bis(fluorosulfonyl)imide salt derivative according to claim 1, characterized in that: In the second step, the vacuum drying temperature is 70~120℃, the vacuum degree is 50~200Pa, and the drying time is 2~8h.