Method for preparing bisfluorosulfonylimide ammonium salt

Abstract

Disclosed is a method for preparing a bisfluorosulfonylimide ammonium salt. According to an embodiment of the present invention, the method for preparing a bisfluorosulfonylimide ammonium salt comprises the steps of: introducing ammonium fluoride (NH4F), fluorinated alkali metal or cesium halide, and a reaction solvent into a reaction vessel and then cooling to a first temperature range; adding bischlorosulfonylimide (HCSI) dropwise to the reaction vessel, raising the temperature to a second temperature range when the exothermic reaction is completed, and then reacting during a first time range; and, when the reaction is completed, filtering to remove impurities and introducing a non-polar solvent into a filtrate to obtain a bisfluorosulfonylimide ammonium salt through a recrystallization process. The present invention can provide a method for preparing a bisfluorosulfonylimide ammonium salt, which is capable of improving the yield of the bisfluorosulfonylimide ammonium salt.

Description

Method for producing bisfluorosulfonylimide ammonium salt

[0001] The present invention relates to a method for producing a bisfluorosulfonylimide ammonium salt, and more particularly, to a method for producing a bisfluorosulfonylimide ammonium salt, which can improve the yield and purity of a bisfluorosulfonylimide ammonium salt by adding cesium fluoride during the production of the bisfluorosulfonylimide ammonium salt.

[0002] Bisfluorosulfonylimide salts (e.g., fluorosulfonylimide alkali metal salts, etc.) are compounds used in various applications, such as electrolytes, especially electrolytes for lithium secondary batteries, fuel cell electrolytes, selective electrophilic fluorinating agents, and infrared absorbing dyes.

[0003] In the production of bisfluorosulfonylimide salts, bisfluorosulfonylimide ammonium salt is useful as an intermediate.

[0004] The conventional method for producing bisfluorosulfonylimide ammonium salt is to produce it by adding an ammonium fluoride reagent to bischlorosulfonylimide. Ammonium fluoride has the advantages of being convenient to use and inexpensive among fluorination reagents, but has the problem of a low fluorine substitution ability, which reduces the product yield.

[0005] Accordingly, the present invention has been devised to solve the above-described problems, and to provide a method for producing bisfluorosulfonylimide ammonium salt capable of improving the yield of bisfluorosulfonylimide ammonium salt.

[0006] In addition, the present invention provides a method for producing a bisfluorosulfonylimide ammonium salt capable of improving the purity of the bisfluorosulfonylimide ammonium salt.

[0007] Other objects of the present invention will become more apparent through the preferred embodiments described below.

[0008] According to one aspect of the present invention, a method for producing a bisfluorosulfonylimide ammonium salt comprises the steps of: adding ammonium fluoride (NH4F), an alkali metal fluoride or a cesium halide, and a reaction solvent to a reaction vessel and then cooling the reaction vessel to a first temperature range; adding bischlorosulfonylimide (HCSI) dropwise to the reaction vessel, and then, when the exothermic reaction is completed, increasing the temperature to a second temperature range and then reacting for a first time range; and, when the reaction is completed, filtering the reaction vessel to remove impurities, adding a non-polar solvent to the filtrate, and obtaining a bisfluorosulfonylimide ammonium salt through a recrystallization process.

[0009] Here, the first temperature range may be a temperature below room temperature, the second temperature range may be a temperature above room temperature, and the first time range may be 1 hour or more.

[0010] Here, the first temperature range may be -20 to 25°C, the second temperature range may be 30 to 90°C, and the first time range may be 2 to 24 hours.

[0011] Here, the second temperature range may be 40 to 85°C, and the first time range may be 4 to 12 hours.

[0012] Here, the fluorinated alkali metal may be cesium fluoride (CsF).

[0013] Here, the equivalent ratio of the ammonium fluoride (NH4F) and the cesium fluoride (CsF) to the bischlorosulfonylimide (HCSI) added above may be 4:0.1 to 0.5.

[0014] Here, the equivalent ratio of the ammonium fluoride (NH4F) and the cesium fluoride (CsF) may be 4:0.3 to 0.5.

[0015] Here, the equivalent ratio of the ammonium fluoride (NH4F) and the cesium fluoride (CsF) to the bischlorosulfonylimide (HCSI) added above may be 2 to 3:0.3.

[0016] Here, the fluorinated alkali metal may be rubidium fluoride (RbF).

[0017] Here, the fluorinated alkali metal is potassium fluoride (KF), sodium fluoride (NaF) or lithium fluoride (LiF) and may be 3000 ppm or less.

[0018] Here, the cesium halide may be any one of cesium chloride (CsCl), cesium bromide (CsBr), and cesium iodide (CsI).

[0019] Here, the equivalent ratio of the ammonium fluoride (NH4F) and the cesium halide to the bischlorosulfonylimide (HCSI) added above may be 2.5:0.3.

[0020] Here, the reaction solvent may be at least one selected from butyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, and ethyl isobutyrate.

[0021] Here, the non-polar solvent may be at least one selected from toluene, chloroform, dichloromethane, 1,2-dichlorobenzene, diethyl ether, dipropyl ether, cyclohexane, chlorobenzene, and xylene.

[0022] The present invention can provide a method for producing a bisfluorosulfonylimide ammonium salt, which can improve the yield of the bisfluorosulfonylimide ammonium salt.

[0023] In addition, the present invention can provide a method for producing a bisfluorosulfonylimide ammonium salt, which can improve the purity of the bisfluorosulfonylimide ammonium salt.

[0024] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated in the drawings and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention. In describing the present invention, detailed descriptions of related known technologies will be omitted if they are deemed to obscure the gist of the present invention.

[0025] Terms such as first, second, etc. may be used to describe various components, but these components should not be limited by these terms. These terms are used solely to distinguish one component from another.

[0026] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes plural expressions unless the context clearly indicates otherwise. In this application, it should be understood that the terms "comprise" or "have" indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof. Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0027] In addition, the terms 'about', 'substantially', etc. used in this specification are used in a meaning close to or at the numerical value when manufacturing and material tolerances inherent to the meanings mentioned are presented, and are used to prevent unscrupulous infringers from unfairly using the disclosure contents in which exact or absolute values ​​are mentioned to aid understanding of the present invention.

[0028]

[0029] The present invention relates to a method for producing bisfluorosulfonylimide ammonium salt, which is a synthetic intermediate of bisfluorosulfonylimide salt having excellent performance as an electrolyte. In particular, the present invention relates to a method for producing bisfluorosulfonylimide ammonium salt, which can improve the yield and purity of bisfluorosulfonylimide ammonium salt by adding a fluorinated alkali metal or a cesium halide during the production of bisfluorosulfonylimide ammonium salt.

[0030] Here, the bis(chlorosulfonyl)imide can be obtained by reacting chlorosulfonic acid with chlorosulfonyl isocyanate. However, the present invention is not limited thereto, and it is sufficient to perform a previously disclosed method or use a commercially available product. In addition, N-(chlorosulfonyl)-N-(fluoroalkylsulfonyl)imide can also be used, and this can be obtained by reacting chlorosulfonyl isocyanate with a fluoroalkylsulfonic acid, or by reacting fluoroalkylsulfonyl isocyanate with chlorosulfonic acid.

[0031] Additionally, the above fluorinated alkali metals may include cesium fluoride (CsF), rubidium fluoride (RbF), potassium fluoride (KF), sodium fluoride (NaF), and lithium fluoride (LiF). The order of fluorine substitution ability of fluorinated alkali metals including ammonium fluoride (NH4F) is as follows.

[0032] CsF > RbF > KF > NaF > NH4F > LiF

[0033] In the present invention, in order to supplement the fluorine substitution ability of ammonium fluoride (NH4F), ammonium fluoride (NH4F) and an alkali metal fluoride are introduced together into the reaction. However, in the present invention, it is most preferable to use cesium fluoride (CsF), which has the best fluorine substitution ability among alkali metal fluorides, but the present invention is not limited thereto. That is, the alkali metal introduced together with ammonium fluoride (NH4F) may be rubidium fluoride (RbF), potassium fluoride (KF), sodium fluoride (NaF), lithium fluoride (LiF), or a mixture thereof. In addition, the alkali metal introduced together with ammonium fluoride (NH4F) may be 3000 ppm or less. More specifically, the potassium fluoride (KF), sodium fluoride (NaF), or lithium fluoride (LiF) introduced together with ammonium fluoride (NH4F) may be 3000 ppm or less. In addition, when ammonium fluoride (NH4F) and fluorinated alkali metal are introduced together in the reaction, the yield and purity of the bisfluorosulfonyl imide ammonium salt are improved, which will be described later through examples.

[0034] In addition, according to another embodiment of the present invention, in order to supplement the fluorine substitution ability of ammonium fluoride (NH4F), ammonium fluoride (NH4F) and cesium halide may be introduced into the reaction together. Here, the cesium halide may be cesium chloride (CsCl), cesium bromide (CsBr), cesium iodide (CsI), etc. In addition, when ammonium fluoride (NH4F) and cesium halide are introduced into the reaction together, the yield and purity of bisfluorosulfonyl imide ammonium salt are improved, which will be described later through examples.

[0035] Additionally, the reaction solvent used in the production of bisfluorosulfonyl imide ammonium salt may be at least one selected from butyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, and ethyl isobutyrate.

[0036] Additionally, the non-polar solvent used for recrystallization of the bisfluorosulfonyl imide ammonium salt may be at least one selected from toluene, chloroform, dichloromethane, and 1,2-dichlorobenzene, diethyl ether, dipropyl ether, cyclohexane, chlorobenzene, and xylene.

[0037]

[0038] The present invention will now be described in more detail through examples. However, it should be understood that these examples are provided solely to facilitate understanding of the present invention and are not intended to limit the scope of the present invention.

[0039]

[0040] [Example 1]

[0041] (Step 1 reaction) Preparation of bischlorosulfonylimide (HCSI)

[0042] 432.2 g (3,709.2 mmol) of chlorosulfonic acid (ClSO3H) was slowly added to 500.0 g (3,532.8 mmol) of chlorosulfonyl isocyanate (OCNSO2Cl), and stirred with a magnetic stirrer. The stirred solution was heated from room temperature to 130°C and reacted for 24 hours. At this time, the progress of the reaction can be determined by whether or not CO2 gas is generated. Specifically, the reaction can be judged to be complete when CO2 gas is no longer generated. After the reaction was completed, 718.4 g (3,356.2 mmol) of bischlorosulfonylimide (HCSI) as a yellow liquid was obtained (yield 95%).

[0043]

[0044] (Step 2 reaction) Preparation of bisfluorosulfonylimide ammonium salt (NH4FSI)

[0045] 20.76 g (560.6 mmol) of ammonium fluoride (NH4F), 2.13 g (14.0 mmol) of cesium fluoride (CsF) were added to 120 g of butyl acetate, cooled to below -5°C, and stirred with a magnetic stirrer. Next, 30 g (140.2 mmol) of bischlorosulfonylimide (HCSI) obtained in the previous step 1 reaction was slowly added dropwise. As heat was generated during this process, the reaction was stirred at 15°C for about 1 hour to ensure a stable reaction. After the exotherm was complete, the reaction temperature was increased to 80°C and the reaction was carried out for 5 hours. After the reaction was completed, it was cooled to 25°C and filtered to remove solid impurities. The filtrate was concentrated and recrystallized by adding 90 g of a non-polar solvent, toluene. As a result of recrystallization, 23.33 g (117.7 mmol) of bisfluorosulfonylimide ammonium salt (NH4FSI) as a white crystalline solid was obtained (yield 84%, purity 99.3%).

[0046] And, the purity of the bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in Example 1 was measured using ion chromatography.

[0047]

[0048] [Examples 2-5]

[0049] (Step 1 reaction) Preparation of bischlorosulfonylimide (HCSI)

[0050] Bischlorosulfonylimide (HCSI) was obtained using the same method as the first step reaction of Example 1 described above.

[0051] (Step 2 reaction) Preparation of bisfluorosulfonylimide ammonium salt (NH4FSI)

[0052] Bischlorosulfonylimide (HCSI) obtained in the above step 1 reaction was reacted to produce bisfluorosulfonylimide ammonium salt (NH4FSI). However, in the step 2 reaction, the equivalent ratio of ammonium fluoride (NH4F) and cesium fluoride (CsF) to bischlorosulfonylimide (HCSI) introduced was changed as shown in Table 1 below, and Examples 2 to 5 were each performed. Then, the purity of the bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in Examples 2 to 5 was measured using ion chromatography.

[0053]

[0054] [Comparative Example 1]

[0055] (Step 1 reaction) Preparation of bischlorosulfonylimide (HCSI)

[0056] Bischlorosulfonylimide (HCSI) was obtained using the same method as the first step reaction of Example 1 described above.

[0057] (Step 2 reaction) Preparation of bisfluorosulfonylimide ammonium salt (NH4FSI)

[0058] Bischlorosulfonylimide (HCSI) obtained in the above step 1 reaction was reacted to produce bisfluorosulfonylimide ammonium salt (NH4FSI). The substantial difference between the step 2 reaction of Comparative Example 1 and the step 2 reactions of Examples 1 to 5 is that cesium fluoride (CsF) was not used.

[0059] 20.76 g (560.4 mmol) of ammonium fluoride (NH4F) was added to 120 g of butyl acetate, cooled to below -5°C, and stirred with a magnetic stirrer. Next, 30 g (140.2 mmol) of bischlorosulfonylimide (HCSI) obtained in the previous step 1 reaction was slowly added dropwise. As heat was generated during this process, the reaction was stirred at 15°C for about 1 hour to ensure a stable reaction. After the exotherm was complete, the reaction temperature was increased to 80°C and the reaction was carried out for 5 hours. After the reaction was completed, the mixture was cooled to 25°C and filtered to remove solid impurities. The filtrate was concentrated and recrystallized by adding 90 g of a non-polar solvent, toluene. As a result of recrystallization, 20.27 g (102.3 mmol) of bisfluorosulfonylimide ammonium salt (NH4FSI) as a white crystalline solid was obtained (yield 73%, purity 98.3%). Then, the purity of the bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in Comparative Example 1 was measured using ion chromatography.

[0060]

[0061] Category NH4FSI Synthesis Results Yield (%) Purity (%) Compared to HCSI Injected NH4F Equivalent CsF Equivalent Example 14eq 0.1eq 84% 98.6 Example 24eq 0.2eq 87% 98.9 Example 34eq 0.3eq 92% 99.1 Example 44eq 0.4eq 91% 99.4 Example 54eq 0.5eq 90% 99.2 Comparative Example 14eq -73 98.3

[0062] Referring to Table 1 above, Examples 1 to 5, in which fluorine substitution was performed using ammonium fluoride (NH4F) and cesium fluoride (CsF) together, showed an improved yield of bisfluorosulfonyl ammonium salt (NH4FSI) compared to Comparative Example 1, in which cesium fluoride (CsF) was not used. In addition, when the amount of cesium fluoride (CsF) used was increased and the yield was measured, the highest yield was observed at 0.3 equivalents, and the yield was maintained similarly when more than that was used. In addition, when ammonium fluoride (NH4F) and cesium fluoride (CsF) were added to the reaction together, the purity was maintained at 98.6% or higher.

[0063] [Examples 6-8]

[0064] (Step 1 reaction) Preparation of bischlorosulfonylimide (HCSI)

[0065] Bischlorosulfonylimide (HCSI) was obtained using the same method as the first step reaction of Example 1 described above.

[0066] (Step 2 reaction) Preparation of bisfluorosulfonylimide ammonium salt (NH4FSI)

[0067] Bischlorosulfonylimide (HCSI) obtained in the above step 1 reaction was reacted to produce bisfluorosulfonylimide ammonium salt (NH4FSI). However, in the step 2 reaction, the equivalent ratio of ammonium fluoride (NH4F) and cesium fluoride (CsF) to bischlorosulfonylimide (HCSI) introduced was changed as shown in Table 2 below, and Examples 6 to 8 were each performed. Then, the purity of the bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in Examples 6 to 8 was measured using ion chromatography.

[0068]

[0069] [Comparative Examples 2-4]

[0070] (Step 1 reaction) Preparation of bischlorosulfonylimide (HCSI)

[0071] Bischlorosulfonylimide (HCSI) was obtained using the same method as the first step reaction of Example 1 described above.

[0072] (Step 2 reaction) Preparation of bisfluorosulfonylimide ammonium salt (NH4FSI)

[0073] Bischlorosulfonylimide (HCSI) obtained in the above-mentioned first-step reaction was reacted to produce bisfluorosulfonylimide ammonium salt (NH4FSI). The substantial difference between the second-step reactions of Comparative Examples 2 to 4 and the second-step reactions of Examples 6 to 8 is that cesium fluoride (CsF) was not used. Comparative Examples 2 to 4 were each performed by varying the equivalent ratio of ammonium fluoride (NH4F) to bischlorosulfonylimide (HCSI) introduced in the second-step reaction as shown in Table 2 below. Then, the purity of the bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in Comparative Examples 2 to 4 was measured using ion chromatography.

[0074]

[0075]

[0076] Classification NH4FSI Synthesis Results Yield (%) Compared to HCSI Injected Purity (%) NH4F Equivalent CsF Equivalent Example 63eq 0.3eq 9299.3 Example 72.5eq 0.3eq 9199.4 Example 82eq 0.3eq 8597.4 Comparative Example 23eq -6895.4 Comparative Example 32.5eq -6192.6 Comparative Example 42eq -5085.2

[0077] Referring to Table 2 above, Examples 6 to 8, in which fluorine substitution was performed using ammonium fluoride (NH4F) and cesium fluoride (CsF) together, showed an improved yield of bisfluorosulfonyl ammonium salt (NH4FSI) compared to Comparative Examples 2 to 4, in which cesium fluoride (CsF) was not used. In addition, when the yield was measured while changing the amount of ammonium fluoride (NH4F) used, the highest yield was shown at 3 equivalents. In addition, when ammonium fluoride (NH4F) and cesium fluoride (CsF) were added to the reaction together, the purity was maintained at 97.4% or higher.

[0078] [Examples 9-11]

[0079] (Step 1 reaction) Preparation of bischlorosulfonylimide (HCSI)

[0080] Bischlorosulfonylimide (HCSI) was obtained using the same method as the first step reaction of Example 1 described above.

[0081] (Step 2 reaction) Preparation of bisfluorosulfonylimide ammonium salt (NH4FSI)

[0082] Bischlorosulfonylimide (HCSI) obtained in the above step 1 reaction was reacted to produce bisfluorosulfonylimide ammonium salt (NH4FSI). However, unlike Example 1, in Examples 9 to 11, cesium halide (CsX, X=Cl, Br, I) was used instead of cesium fluoride (CsF). In the step 2 reaction, the equivalent ratio of ammonium fluoride and cesium halide (CsX) to bischlorosulfonylimide (HCSI) introduced was varied as shown in Table 3 below, and Examples 9 to 11 were each performed. Then, the purity of bisfluorosulfonylimide ammonium salt (NH4FSI) obtained in Examples 9 to 11 was measured using ion chromatography.

[0083]

[0084] Synthesis results of NH4FSI Yield (%) compared to HCSI input Purity (%) NH4F Equivalent CsX Equivalent Example 92.5eq X=Cl 0.4eq 91% 99.2 Example 102.5eq X=Br 0.4eq 89% 99.1 Example 112.5eq X=I 0.4eq 85% 98.4

[0085] Referring to Table 3 above, when the amount of ammonium fluoride (NH4F) and the amount of cesium halide (CsX) were fixed and the type of cesium halide (CsX) was changed, the yield was maintained at 85% or higher, and the purity was maintained at 98.4% or higher. In addition, the highest yield and purity were observed when cesium chloride (CsCl) was used among the cesium halides (CsX).

[0086] The above preferred embodiments of the present invention are disclosed for the purpose of illustration, and those skilled in the art with ordinary knowledge of the present invention will be able to make various modifications, changes, and additions within the spirit and scope of the present invention, and such modifications, changes, and additions should be considered to fall within the scope of the following patent claims.

Claims

1. Ammonium fluoride (NH 4 F), a step of adding a fluorinated alkali metal or a halide cesium, and a reaction solvent to a reaction vessel and then cooling to a first temperature range; Step of adding bischlorosulfonylimide (HCSI) dropwise to the above reaction vessel, then increasing the temperature to a second temperature range when the exothermic reaction is completed, and then reacting for a first time range; and A method for producing a bisfluorosulfonylimide ammonium salt, comprising the steps of filtering to remove impurities when the reaction is completed, adding a non-polar solvent to the filtrate, and obtaining a bisfluorosulfonylimide ammonium salt through a recrystallization process.

2. In paragraph 1, The above first temperature range is a temperature below room temperature, The above second temperature range is a temperature above room temperature, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the first time range is 1 hour or longer.

3. In paragraph 2, The above first temperature range is -20 to 25℃, The above second temperature range is 30 to 90℃, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the first time range is 2 to 24 hours.

4. In paragraph 3, The above second temperature range is 40 to 85℃, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the first time range is 4 to 12 hours.

5. In paragraph 1, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the above-mentioned fluorinated alkali metal is cesium fluoride (CsF).

6. In paragraph 5, The ammonium fluoride (NH) compared to the bischlorosulfonylimide (HCSI) added above 4 A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the equivalent ratio of F) and the above cesium fluoride (CsF) is 4:0.1 to 0.

5.

7. In paragraph 6, The above ammonium fluoride (NH 4 A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the equivalent ratio of F) and the above cesium fluoride (CsF) is 4:0.3 to 0.

5.

8. In paragraph 5, The ammonium fluoride (NH) compared to the bischlorosulfonylimide (HCSI) added above 4 A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the equivalent ratio of F) and the above cesium fluoride (CsF) is 2 to 3:0.

3.

9. In paragraph 1, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the above-mentioned fluorinated alkali metal is rubidium fluoride (RbF).

10. In paragraph 1, A method for producing a bisfluorosulfonylimide ammonium salt, characterized in that the above-mentioned fluorinated alkali metal is potassium fluoride (KF), sodium fluoride (NaF) or lithium fluoride (LiF) and the amount is 3000 ppm or less.

11. In paragraph 1, The above halide cesium is, A method for producing a bisfluorosulfonylimide ammonium salt, characterized in that the salt is any one of cesium chloride (CsCl), cesium bromide (CsBr), and cesium iodide (CsI).

12. In paragraph 11, The ammonium fluoride (NH) compared to the bischlorosulfonylimide (HCSI) added above 4 F) A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the equivalent ratio of the above halide cesium and the bisfluorosulfonylimide is 2.5:0.

3.

13. In paragraph 1, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the reaction solvent is at least one selected from butyl acetate, ethyl acetate, isopropyl acetate, isobutyl acetate, and ethyl isobutyrate.

14. In paragraph 1, A method for producing bisfluorosulfonylimide ammonium salt, characterized in that the nonpolar solvent is at least one selected from toluene, chloroform, dichloromethane, 1,2-dichlorobenzene, diethyl ether, dipropyl ether, cyclohexane, chlorobenzene and xylene.