Preparation Method of Fluorosulfuric Acid Lactone, Its Electrolyte and Electrochemical Device

Abstract

The present invention discloses a preparation method of fluorosulfuric acid lactone, an electrolyte and an electrochemical device thereof. The preparation method of fluorosulfuric acid lactone of the present invention comprises the following steps: Step S1, in an aprotic solvent, mixing a chlorosulfuric acid lactone compound with a quaternary ammonium fluoride salt, then adding a nucleophilic catalyst and reacting to obtain a crude product of fluorosulfuric acid lactone; Step S2, performing alkali washing on the crude product of fluorosulfuric acid lactone, then separating the organic phase and performing vacuum distillation to obtain fluorosulfuric acid lactone, wherein the quaternary ammonium fluoride salt is tetramethylammonium fluoride or tetraethylammonium fluoride, and the nucleophilic catalyst is triethylamine or pyridine. The fluorosulfuric acid lactone prepared by the method of the present invention has high yield and high purity, and the preparation method is simple and suitable for industrial production.

Description

Technical Field

[0001] The present invention relates to the technical field of batteries, and in particular to a preparation method of fluorosulfuric acid lactone, an electrolyte and an electrochemical device thereof. Background Art

[0002] With the continuous improvement of people's requirements for the performance of lithium batteries, how to obtain a lithium battery with stable capacity and high safety performance has become a research hotspot. As an indispensable component of lithium batteries, electrolyte additives have an important impact on the performance of lithium batteries such as safety and lifespan. Currently, common electrolyte additives include cyclic carbonates, organic sulfates, sulfonates, and lithium salts. Among them, organic sulfate additives have become important addition targets because they can inhibit the decline of the initial capacity of the battery, increase the initial discharge capacity, reduce the swelling of the battery after high-temperature storage, and improve the charge and discharge performance and cycle times of the battery.

[0003] In related research, organic sulfate additives are mainly fluorosulfate compounds. These compounds are usually directly synthesized from sulfate compounds as raw materials, using dichloromethane as a solvent. Intermediate 4-bromo-sulfate is obtained by adding NBS in batches, and then the obtained intermediate is placed in dichloromethane with organic potassium fluoride (such as sodium fluoride), and an exchange reaction is carried out in the presence of cyclodextrin. However, this fluorine exchange using inorganic fluorination reagents has weak fluorination ability, resulting in a low yield of the finally obtained fluorosulfate compounds, and the dichloromethane solvent used in the fluorination reaction has high toxicity, which is not conducive to improving the safety of the preparation.

[0004] Therefore, the present invention provides a preparation method of fluorosulfuric acid lactone, an electrolyte and an electrochemical device thereof. This method can effectively improve the yield of fluorosulfate compounds, and the raw materials used have relatively higher safety. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art. For this purpose, the present invention provides a preparation method of fluorosulfuric acid lactone, an electrolyte and an electrochemical device thereof. Using this preparation method can effectively improve the yield and purity of fluorosulfate compounds, and the preparation method is simple and has high safety.

[0006] The present invention also provides an electrolyte.

[0007] The present invention also provides an electrochemical device.

[0008] In the first aspect of the present invention, a preparation method of fluorosulfuric acid lactone is provided, including the following steps:

[0009] Step S1: In an aprotic solvent, mix a chlorosulfuric acid lactone compound with a quaternary ammonium fluoride, then add a nucleophilic catalyst and react to obtain a crude product of fluorosulfuric acid lactone;

[0010] Step S2: Wash the crude product of fluorosulfuric acid lactone with alkali, then separate the organic phase and perform vacuum distillation to obtain fluorosulfuric acid lactone.

[0011] The preparation method according to the embodiment of the present invention has at least the following beneficial effects:

[0012] (1) During the preparation of the fluorosulfuric acid lactone of the present invention, a quaternary ammonium fluoride is used to replace the conventional inorganic fluorinating reagent, effectively improving the fluorination efficiency. It is speculated that this may be because the cation structure in the quaternary ammonium fluoride is relatively loose and the binding effect on fluoride ions is weak, making the fluoride ions highly active, thereby improving the fluorination efficiency.

[0013] (2) During the preparation of the fluorosulfuric acid lactone of the present invention, a nucleophilic catalyst is also used. It has excellent nucleophilicity and can form an ion pair with the quaternary ammonium salt, further improving the dissociation effect of fluoride ions, thereby accelerating the reaction rate, reducing side reactions and increasing the yield.

[0014] In some embodiments of the present invention, the aprotic solvent includes at least one of tetrahydrofuran, acetone, N,N-dimethylacetamide, dimethyl sulfoxide, and sulfolane.

[0015] In some embodiments of the present invention, the chlorosulfuric acid lactone compound is vinyl chlorosulfate or allyl chlorosulfate;

[0016] Preferably, the vinyl chlorosulfate is selected from one of monochloro vinyl sulfonate and dichloro vinyl sulfonate; and / or the allyl chlorosulfate is selected from one of monochloro allyl sulfonate, dichloro allyl sulfonate, and trichloro allyl sulfonate.

[0017] In some embodiments of the present invention, the quaternary ammonium fluoride is tetramethylammonium fluoride or tetraethylammonium fluoride.

[0018] In some embodiments of the present invention, the nucleophilic catalyst is selected from at least one of triethylamine and pyridine.

[0019] Triethylamine has a small steric hindrance and strong nucleophilicity, and can be used as a catalytic component to form an ion pair with the quaternary ammonium salt, thereby effectively improving the dissociation effect of fluoride ions.

[0020] In some embodiments of the present invention, the molar concentration ratio of the chlorosulfuric acid lactone compound, the quaternary ammonium fluoride, and the nucleophilic catalyst is 1:2 - 6:1.2 - 3.

[0021] In some embodiments of the present invention, the temperature of the reaction is 65 to 85 °C, and the time of the reaction is 2 to 4 h.

[0022] In some embodiments of the present invention, after the reaction, it further includes removing insoluble impurities in the reaction product.

[0023] In some embodiments of the present invention, the alkali washing is specifically as follows: adding a saturated Na 2 CO 3 solution with a mass fraction of 8 to 12% to the crude fluorosulfuric acid lactone, adjusting the pH value to 7 to 8, and standing for liquid separation.

[0024] In some embodiments of the present invention, after separating the organic phase, it further includes adding anhydrous magnesium sulfate for drying treatment.

[0025] In a second aspect of the present invention, there is provided an electrolyte solution including the fluorosulfuric acid lactone prepared by the preparation method of the first aspect.

[0026] The electrolyte solution according to the embodiment of the present invention has at least the following beneficial effects: Using the fluorosulfuric acid lactone obtained by the preparation method of the present invention as an additive component of the electrolyte solution can effectively inhibit the decline of the initial capacity of the battery, increase the initial discharge capacity, reduce the expansion of the battery after high-temperature storage, and improve the charge and discharge performance and cycle times of the battery, which is of great significance for improving the service life and safety of the battery.

[0027] In a third aspect of the present invention, there is provided an electrochemical device including the electrolyte solution described in the second aspect.

[0028] Other features and advantages of the present invention will be described in the following description of the specification, and in part, will be obvious from the description of the specification, or will be understood by implementing the present invention. Detailed Embodiments

[0029] The following will clearly and completely describe the concept and technical effects generated by the present invention in combination with embodiments to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative efforts belong to the scope of protection of the present invention.

[0030] In the description of the present invention, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0031] In the description of the embodiments of the present invention, the CAS number of the tetramethylammonium fluoride is 17787-40-5;

[0032] The CAS number of the tetraethylammonium fluoride is 429-41-4.

[0033] For those not specified with specific conditions in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. For the reagents or instruments not specified with the manufacturer, they are all conventional products that can be obtained by commercial purchase.

[0034] Example 1

[0035] The fluorosulfuric acid lactone prepared in this example is vinyl fluorosulfate, and its structural formula is shown in Formula I:

[0036]

[0037] The preparation method of vinyl fluorosulfate provided in this example specifically includes the following steps:

[0038] Add 0.8 mol of vinyl chlorosulfate, 2 mol of tetramethylammonium fluoride, and 200 mL of acetone to a three-necked round-bottom flask equipped with a thermometer, a condenser, and a stirring device, mix well, and then slowly add 1.2 mol of triethylamine (nucleophilic catalyst) under the condition that the reaction temperature is 65-70 °C, mix well, then adjust the heating temperature to about 80 °C, keep the reaction for 2 h and then end the reaction. After standing at room temperature until the temperature drops to 30 °C, filter, collect the filtrate, and then add a 10% mass fraction of Na 2 CO 3 solution, adjust the pH value of the filtrate to 7-8, stand still and wait for the reaction system to separate into layers, separate the aqueous phase to obtain the organic phase, then dry it with anhydrous magnesium sulfate, filter out the anhydrous magnesium sulfate again after drying to obtain the secondary filtrate, and carry out vacuum distillation on the secondary filtrate under the condition of 35-40 °C to obtain vinyl fluorosulfate with a purity of 99.83% and a yield of 92.8%.

[0039] Example 2

[0040] The fluorosulfuric acid lactone prepared in this example is vinyl difluorosulfate, and its structural formula is shown in Formula II:

[0041]

[0042] The preparation method of vinyl difluorosulfate provided in this example specifically includes the following steps:

[0043] Add 0.3 mol of vinyl dichlorosulfate, 1.2 mol of tetramethylammonium fluoride, and 200 mL of tetrahydrofuran to a three-necked round-bottom flask equipped with a thermometer, a condenser, and a stirring device, mix well, and then slowly add 0.8 mol of triethylamine under the condition that the reaction temperature is 65 - 70 °C, mix well, then adjust the heating temperature to about 80 °C, keep the reaction for 2 h and then end the reaction. After standing at room temperature until the temperature drops to 30 °C, add a 10% Na 2 CO 3 solution, adjust the pH value of the system to 7 - 8, let it stand for the reaction system to separate into layers, separate the aqueous phase to obtain the organic phase, then dry it with anhydrous magnesium sulfate, filter after drying to remove the anhydrous magnesium sulfate after water absorption, obtain the filtrate, and finally carry out vacuum distillation on the filtrate under the condition of 35 - 40 °C to obtain vinyl difluorosulfate, with a purity of 99.90% and a yield of 93.7%.

[0044] Example 3

[0045] The fluorosulfuric acid lactone prepared in this example is allyl monofluorosulfate, and its structural formula is shown in Formula III:

[0046]

[0047] The preparation method of allyl monofluorosulfate provided in this example specifically includes the following steps:

[0048] Add 0.6 mol of allyl chlorosulfate, 1.5 mol of tetramethylammonium fluoride, and 200 mL of acetone to a three-necked round-bottom flask equipped with a thermometer, a condenser, and a stirring device, mix well, and then slowly add 1 mol of triethylamine under the condition that the reaction temperature is 65 - 70 °C, mix well, then adjust the heating temperature to about 80 °C, keep the reaction for 2 h and then end the reaction. After standing at room temperature until the temperature drops to 30 °C, add a 10% Na 2 CO 3 solution, adjust the pH value of the system to 7 - 8, let it stand for the reaction system to separate into layers, separate the aqueous phase to obtain the organic phase, then dry it with anhydrous magnesium sulfate, filter after drying to remove the anhydrous magnesium sulfate after water absorption, obtain the filtrate, and finally carry out vacuum distillation on the filtrate under the condition of 35 - 40 °C to obtain allyl monofluorosulfate, with a purity of 99.89% and a yield of 92.6%.

[0049] Example 4

[0050] The fluorosulfuric acid lactone obtained in this example is allyl trifluorothiosulfate, and its structural formula is as shown in Formula IV:

[0051]

[0052] The preparation method of allyl trifluorothiosulfate provided in this example specifically includes the following steps:

[0053] Add 0.4 mol of allyl trichlorothiosulfate, 2 mol of tetramethylammonium fluoride, and 200 mL of acetone to a three-necked round-bottom flask equipped with a thermometer, a condenser, and a stirring device, mix well, then slowly add 1 mol of triethylamine under the condition that the reaction temperature is 65 - 70 °C, mix well, then adjust the heating temperature to about 80 °C, keep the temperature for reaction for 2 h and then end the reaction. After standing at room temperature until the temperature drops to 30 °C, add a 10% Na 2 CO 3 solution, adjust the pH value of the system to 7 - 8, let it stand for the reaction system to separate into layers, separate the aqueous phase to obtain the organic phase, then dry it with anhydrous magnesium sulfate. After drying, filter to remove the anhydrous magnesium sulfate after water absorption to obtain the filtrate. Finally, carry out vacuum distillation on the filtrate under the condition of 35 - 40 °C to obtain allyl trifluorothiosulfate, with a purity of 99.92% and a yield of 91.4%.

[0054] Example 5

[0055] The fluorosulfuric acid lactone obtained in this example is vinyl difluorothiosulfate, and its preparation method refers to that shown in Example 2. The difference from Example 2 is that tetramethylammonium fluoride is replaced by tetraethylammonium fluoride, and the other conditions remain unchanged, to obtain vinyl difluorothiosulfate, with a purity of 99.89% and a yield of 91.7%.

[0056] Example 6

[0057] The fluorosulfuric acid lactone obtained in this example is vinyl difluorothiosulfate, and its preparation method refers to that shown in Example 2. The difference from Example 2 is that the nucleophilic catalyst triethylamine is replaced by pyridine, and the other conditions remain unchanged, to obtain vinyl difluorothiosulfate, with a purity of 99.81% and a yield of 90.8%.

[0058] Comparative Example 1

[0059] The fluorosulfuric acid lactone obtained in this comparative example is vinyl difluorothiosulfate, and its preparation method refers to that shown in Example 2. The difference from Example 2 is that tetramethylammonium fluoride is replaced by potassium fluoride, and the other conditions remain unchanged, to obtain vinyl difluorothiosulfate, with a purity of 98.75% and a yield of 78.6%.

[0060] Comparative Example 2

[0061] The fluorosulfuric acid lactone prepared in this comparative example is vinyl difluorosulfate. Its preparation method refers to that shown in Example 2. The difference from Example 2 is that triethylamine was not added in this comparative example, and the other conditions remained unchanged. Vinyl difluorosulfate was obtained, with a purity of 99.88% and a yield of 75.22%.

[0062] From the yield data and purity data of the fluorosulfuric acid lactone prepared by the preparation methods of the above Examples 1 to 6, it can be seen that during the preparation of the fluorosulfuric acid lactone, the yield of the fluorosulfuric acid lactone prepared by using a quaternary ammonium fluoride-based fluorinating agent in combination with a nucleophilic catalyst can reach more than 91%, and its purity can reach more than 99.5%.

[0063] In addition, compared with the use of a conventional inorganic fluorination reagent group (Comparative Example 1), the results show that replacing the conventional inorganic fluorination reagent with a quaternary ammonium fluoride can effectively improve the fluorination efficiency. It is speculated that this may be because the cation structure in the quaternary ammonium fluoride is relatively loose and the binding effect on fluoride ions is weak, making the activity of fluoride ions very high, thereby improving the fluorination efficiency.

[0064] The above has described the embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made without departing from the gist of the present invention within the knowledge scope of those of ordinary skill in the art. In addition, the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

Claims

1. A preparation method of a fluorosulfuric acid lactone compound, characterized in that, it comprises the following steps: Step S1: In an aprotic solvent, mix a chlorosulfuric acid lactone compound with a quaternary ammonium fluoride, and then add a nucleophilic catalyst and react to obtain a crude fluorosulfuric acid lactone; wherein the chlorosulfuric acid lactone compound is vinyl chlorosulfate or allyl chlorosulfate, the quaternary ammonium fluoride is tetramethylammonium fluoride or tetraethylammonium fluoride, and the nucleophilic catalyst is selected from at least one of triethylamine and pyridine; Step S2: Wash the crude fluorosulfuric acid lactone with alkali, then separate the organic phase and perform vacuum distillation to obtain the fluorosulfuric acid lactone.

2. The preparation method according to claim 1, characterized in that, the aprotic solvent comprises at least one of tetrahydrofuran, acetone, N,N-dimethylacetamide, dimethyl sulfoxide and sulfolane.

3. The preparation method according to claim 1, characterized in that, the vinyl chlorosulfate is selected from one of vinyl monochlorosulfate and vinyl dichlorosulfate; the allyl chlorosulfate is selected from one of allyl monochlorosulfate, allyl dichlorosulfate and allyl trichlorosulfate.

4. The preparation method according to claim 1, characterized in that, the molar concentration ratio of the chlorosulfuric acid lactone compound, the quaternary ammonium fluoride and the nucleophilic catalyst is 1:2 to 6:1.2 to 3.

5. The preparation method according to claim 1, characterized in that, the temperature of the reaction is 65 to 85 °C, and the time of the reaction is 2 to 4 h.

6. The preparation method according to claim 1, characterized in that, The caustic washing is specifically as follows: adding a saturated Na 2 CO 3 solution with a mass fraction of 8-12% to the crude product of fluorosulfuric acid lactone, adjusting the pH value to 7-8, and standing for layering.

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