Silicon difluorophosphate compound and preparation method thereof

Abstract

According to the silicon difluorophosphate compound and the preparation method thereof, in the reaction of a chlorosilane compound and difluorophosphate, the molar ratio of the chlorosilane compound to the difluorophosphate is set to be larger than or equal to 2, and meanwhile the reaction temperature is controlled to be smaller than or equal to 40 DEG C. On one hand, when the parameters are controlled at the same time, the reaction of the chlorosilane compound and water is prior to the reaction of the chlorosilane compound and difluorophosphate, and the influence of water on the difluorophosphate silicon ester compound is reduced; and on the other hand, the silicon difluorophosphate compound and the excessive chlorosilane compound can form a complexing effect, so that the chlorosilane compound can form a protective effect on the silicon difluorophosphate compound, the silicon difluorophosphate compound is not easy to hydrolyze, and the conversion rate of the reaction and the yield of the silicon difluorophosphate compound are improved.

Description

Technical Field

[0001] This application belongs to the field of chemical material preparation technology, and in particular relates to a difluorophosphate silicon ester compound and its preparation method. Background Technology

[0002] With the rapid development of the new energy industry, especially the lithium battery market, the demand for difluorophosphate silicon ester compounds, as a component of electrolytes, is increasing. Currently, in the industrial preparation of difluorophosphate silicon ester compounds, difluorophosphate is generally prepared by dissolving difluorophosphate in a solvent to obtain a difluorophosphate solution, and then adding chlorosilane compounds dropwise to the difluorophosphate solution, allowing the difluorophosphate to react with the chlorosilane compounds to obtain the difluorophosphate silicon ester compounds.

[0003] However, existing methods for preparing difluorophosphate silicon ester compounds suffer from low yields. Optimizing reaction conditions to improve the yield of difluorophosphate silicon ester compounds is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0004] The embodiments of this application provide a difluorophosphate silicon ester compound and a method for preparing the same, which aims to at least partially solve the aforementioned technical problems.

[0005] In a first aspect, embodiments of this application provide a method for preparing a difluorophosphate silicon ester compound, comprising: A chlorosilane compound and a difluorophosphate are provided, wherein the molar ratio of the chlorosilane compound to the difluorophosphate is greater than or equal to 2; The chlorosilane compound is reacted with the difluorophosphate at a temperature of less than or equal to 40°C to obtain a mixture containing the difluorophosphate silyl ester compound; The mixture was purified to obtain the difluorophosphate silicon ester compound; The structure of the difluorophosphate silyl ester compound is shown in formula (1), the structure of the chlorosilane compound is shown in formula (2), and the structure of the difluorophosphate is shown in formula (3). Equation (1); Equation (2); Equation (3); R1, R2, and R3 are each independently selected from at least one of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 alkoxy, and C6-C20 aromatic groups; M is selected from at least one of sodium ion, potassium ion, and ammonium ion.

[0006] In one embodiment, the molar ratio of the chlorosilane compound to the difluorophosphate is (2-5):1.

[0007] In one embodiment, R1, R2, and R3 are each independently selected from at least one of C1-C5 alkyl, C2-C5 alkenyl, C2-C5 alkynyl, C1-C5 alkoxy, and C6-C10 aromatic groups.

[0008] In one embodiment, R1, R2, and R3 are each independently selected from at least one of C1-C2 alkyl, vinyl, and benzene ring groups.

[0009] In one embodiment, the chlorosilane compound includes at least one of the following compounds: , , , , .

[0010] In one embodiment, the difluorophosphate includes at least one of sodium difluorophosphate, ammonium difluorophosphate, and potassium difluorophosphate.

[0011] In one embodiment, the difluorophosphate silicate compound includes at least one of the following compounds: , , , , .

[0012] In one embodiment, the step of reacting the chlorosilane compound with the difluorophosphate at a temperature of less than or equal to 40°C to obtain a mixture satisfies at least one of the following conditions: The chlorosilane compound reacts with the difluorophosphate under stirring conditions; The chlorosilane compound reacts with the difluorophosphate in an inert gas atmosphere; The reaction temperature between the chlorosilane compound and the difluorophosphate is -10°C to 40°C. The reaction time between the chlorosilane compound and the difluorophosphate is 0.25 h to 10 h.

[0013] In one embodiment, the difluorophosphate is dehydrated before use.

[0014] In one embodiment, the dehydration operation includes the following steps: adding difluorophosphate to a dry reaction vessel, then adding an inert solvent, stirring and mixing under nitrogen protection, then slowly adding thionyl chloride dropwise, controlling the temperature at 10~30°C during the dropwise addition, raising the temperature to 30-70°C after the dropwise addition is complete, reacting for 1-4 hours, and after the reaction is complete, removing the inert solvent and excess thionyl chloride by vacuum distillation to obtain dry difluorophosphate solid.

[0015] In one embodiment, the dehydration operation satisfies at least one of the following: (1) The mass of the inert solvent is 2-6 times the mass of the difluorophosphate; (2) The inert solvent includes at least one of ethyl methyl carbonate and dichloromethane; (3) The molar ratio of thionyl chloride to difluorophosphate is (1.2-2.0):1.

[0016] In one embodiment, the purification process specifically includes: The mixture is filtered to obtain a filtrate; The filtrate is subjected to vacuum distillation to remove the chlorosilane compounds from the filtrate, thereby obtaining the difluorophosphate silane compounds.

[0017] In one embodiment, the temperature of the vacuum distillation process is 30°C-70°C, and / or the vacuum degree of the vacuum distillation process is -0.09 MPa to -0.01 MPa. In a second aspect, embodiments of this application also provide a difluorophosphate silicon ester compound, which is prepared using the preparation method described above.

[0018] In one embodiment, the difluorophosphate silicate compound includes at least one of the following compounds: , , , , .

[0019] The beneficial effects of the embodiments of this application are as follows: Chlorosilane compounds can react with difluorophosphates to form difluorophosphate silyl esters. However, because the reactants and solvents introduce a small amount of water, the difluorophosphate silyl esters can undergo hydrolysis with water, leading to a decrease in the yield of difluorophosphate silyl esters. In this application, in the reaction of chlorosilane compounds with difluorophosphates, the molar ratio of chlorosilane compounds to difluorophosphates is set to be greater than or equal to 2, and the reaction temperature is controlled at less than or equal to 40°C. On the one hand, under these conditions, the reaction of chlorosilanes with water is preferential to the reaction of chlorosilanes with difluorophosphate. Before a large amount of the target product is generated, the excess chlorosilanes can consume at least part of the water in the reactants, reducing the influence of water on the product difluorophosphate silyl esters. On the other hand, difluorophosphate silyl esters can dissolve in the excess chlorosilanes and form complexes with them, thus protecting the difluorophosphate silyl esters and making them less prone to hydrolysis. The molar ratio of chlorosilanes to difluorophosphate is greater than or equal to 2. The excess chlorosilanes ensure the protective effect of chlorosilanes on difluorophosphate silyl esters and reduce the influence of the interaction between chlorosilanes and difluorophosphate silyl esters on the reaction process, allowing sufficient chlorosilanes to continue reacting with difluorophosphate as a raw material, thereby improving the conversion rate. Therefore, in the preparation of difluorophosphate silicon ester compounds, the molar ratio of reactant raw material chlorosilane compound to difluorophosphate is greater than or equal to 2, and the reaction temperature is controlled at less than or equal to 40°C, so that the generated difluorophosphate silicon ester compound is less prone to hydrolysis reaction, and at the same time, the conversion rate and yield of difluorophosphate silicon ester compound are improved. Attached Figure Description

[0020] Figures 1 to 3 The difluorophosphate silicon ester compound prepared in Example 1 19 F NMR spectrum, 31 P NMR spectrum and 1 H NMR spectrum; Figures 4 to 6 The difluorophosphate silicon ester compound prepared in Example 2 19 F NMR spectrum, 31 P NMR spectrum and 1 H NMR spectrum; Figures 7 to 9 The difluorophosphate silicon ester compound prepared in Example 3 19 F NMR spectrum, 31 P NMR spectrum and 1 H NMR spectrum; Figures 10 to 12The difluorophosphate silicon ester compound prepared in Example 4 19 F NMR spectrum, 31 P NMR spectrum and 1 H NMR spectrum. Detailed Implementation

[0021] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation; while "inner" and "outer" refer to the outline of the device.

[0022] In related technologies, the preparation methods of difluorophosphate silicon ester compounds suffer from low yields and require further improvement. This application provides a method for preparing difluorophosphate silicon ester compounds, comprising: S1. Provide chlorosilane compounds and difluorophosphates, wherein the molar ratio of chlorosilane compounds to difluorophosphates is greater than or equal to 2; S2. React chlorosilane compounds with difluorophosphate at a temperature of less than or equal to 40°C to obtain a mixture containing difluorophosphate silyl ester compounds; S3. The mixture is purified to obtain difluorophosphate silicon ester compounds; Among them, the structures of difluorophosphate silicon ester compounds are shown in formula (1), the structures of chlorosilane compounds are shown in formula (2), and the structures of difluorophosphates are shown in formula (3): Equation (1); Equation (2); Equation (3); R1, R2, and R3 are each independently selected from at least one of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 alkoxy, and C6-C20 aromatic groups; M is selected from at least one of sodium ion, potassium ion, and ammonium ion.

[0023] In this embodiment, chlorosilane compounds can react with difluorophosphates to form difluorophosphate silyl ester compounds, as shown in the following reaction formula: .

[0024] In related technologies, the preparation of difluorophosphate silicon ester compounds generally involves dissolving difluorophosphate in a solvent to obtain a difluorophosphate solution, and then adding chlorosilane compounds dropwise to the difluorophosphate solution. This allows the difluorophosphate to react with the chlorosilane compounds to produce the difluorophosphate silicon ester compounds. Because difluorophosphate or solvents can easily introduce small amounts of water, when the chlorosilane compounds are added to the difluorophosphate solution, the small amount of chlorosilane compounds will immediately react with a large amount of difluorophosphate to produce the target product, the difluorophosphate silicon ester compound. However, since difluorophosphate silicon ester compounds are sensitive to water, the resulting target product will undergo a hydrolysis reaction with water, leading to a decrease in the yield of the difluorophosphate silicon ester compound.

[0025] In the embodiments of this application, when preparing difluorophosphate silicon ester compounds, the molar ratio of reactant raw material chlorosilane compound to difluorophosphate is set to be greater than or equal to 2, and the reaction temperature is controlled at less than or equal to 40°C. On the one hand, when chlorosilanes are present in large quantities and the reaction temperature is controlled at less than or equal to 40°C, chlorosilanes will react with water preferentially over difluorophosphates. This consumes at least some of the water in the reactants before the target product is generated in large quantities, reducing the influence of water on difluorophosphate silanes. On the other hand, difluorophosphate silanes are soluble in chlorosilanes and form complexes with them, thus protecting the difluorophosphate silanes and making them less prone to hydrolysis. Setting the molar ratio of chlorosilanes to difluorophosphate to greater than or equal to 2, with an excess of chlorosilanes, ensures the protective effect of chlorosilanes on difluorophosphate silanes. At the same time, it reduces the influence of the interaction between chlorosilanes and difluorophosphate silanes on the reaction process, allowing sufficient chlorosilanes to continue reacting with difluorophosphates as raw materials, thereby improving the conversion rate. Therefore, in the preparation of difluorophosphate silicon ester compounds, the molar ratio of chlorosilane compounds to difluorophosphate is set to be greater than or equal to 2, and the reaction temperature is controlled at less than or equal to 40°C, so that the generated difluorophosphate silicon ester compounds are less prone to hydrolysis reaction, and at the same time, the conversion rate and yield of difluorophosphate silicon ester compounds are improved.

[0026] In this embodiment, no additional organic solvent was used in the reaction between chlorosilane compounds and difluorophosphate, and the reaction was carried out by directly mixing the chlorosilane compounds and difluorophosphate, making the operation simple.

[0027] In one embodiment, the molar ratio of the chlorosilane compound to difluorophosphate is (12-5):1. Optionally, the molar ratio of the chlorosilane compound to difluorophosphate can be any one or any two of the following: 2:1, 2.2:1, 2.5:1, 2.8:1, 3:1, 3.2:1, 3.4:1, 3.6:1, 3.8:1, 4:1, 4.2:1, 4.4:1, 4.6:1, 4.8:1, 5:1, etc., and is not limited herein. In this embodiment, when the molar ratio of the chlorosilane compound to difluorophosphate is less than 2:1, the protective effect of the chlorosilane compound on the difluorophosphate silane compound is easily reduced. At the same time, it is easy to result in too little content of the chlorosilane compound that continues to react with difluorophosphate, thus reducing the reaction conversion rate. When the molar ratio of chlorosilane compounds to difluorophosphate is greater than 5:1, it easily leads to an excessive content of chlorosilane compounds in the mixture, increasing the difficulty of subsequent purification of difluorophosphate silane compounds. Setting the molar ratio of chlorosilane compounds to difluorophosphate to (2-5):1 can ensure the protective effect of chlorosilane compounds on difluorophosphate silane compounds, making difluorophosphate silane compounds less prone to hydrolysis. At the same time, it improves the conversion rate of the reaction and reduces the purification difficulty, which is beneficial to improving the yield and purity of the product.

[0028] The reaction temperature can be any temperature below or equal to 40°C, such as 40°C, 30°C, 20°C, 10°C, 0°C, and temperatures below 0°C. When the reaction temperature is above 40°C, the reaction between chlorosilane compounds and difluorophosphates tends to compete with the reaction between chlorosilane compounds and water. Chlorosilane compounds preferentially react with difluorophosphates to form difluorophosphate silyl esters, and these silyl phosphate esters preferentially undergo hydrolysis, leading to a decrease in the yield of difluorophosphate silyl esters. Controlling the reaction temperature to below or equal to 40°C favors the reaction between chlorosilane compounds and water over the reaction between chlorosilane compounds and difluorophosphates. The chlorosilane compounds can first consume at least some of the water in the reactants, reducing the influence of water on the difluorophosphate silyl esters. This makes the difluorophosphate silyl esters less prone to hydrolysis, thus increasing the yield of difluorophosphate silyl esters.

[0029] In one embodiment, R1, R2, and R3 are each independently selected from at least one of C1-C5 alkyl, C2-C5 alkenyl, C2-C5 alkynyl, C1-C5 alkoxy, and C6-C10 aromatic groups.

[0030] In one embodiment, R1, R2, and R3 are each independently selected from at least one of C1-C2 alkyl, vinyl, and benzene ring groups. In this embodiment, the independent selection of R1, R2, and R3 from the above-mentioned groups can reduce the steric hindrance of chlorosilane compounds, improve reactivity, and enhance the complexation protection effect.

[0031] In one embodiment, the chlorosilane compound includes at least one of the following compounds: , , , , .

[0032] In this embodiment, the above-mentioned chlorosilane compounds can be purchased directly or prepared by ourselves. Specifically, compounds of formula (1-1) (CAS No.: 75-77-4), (1-2) (CAS No.: 1719-58-0), (1-3) (CAS No.: 994-30-9), (1-4) (CAS No.: 768-33-2), and (1-5) (CAS No.: 144-79-6) can be purchased directly.

[0033] In one embodiment, the difluorophosphate includes at least one of sodium difluorophosphate, ammonium difluorophosphate, and potassium difluorophosphate.

[0034] In one embodiment, in step S2, the chlorosilane compound reacts with difluorophosphate under stirring conditions, which can uniformly disperse the reactants, avoid excessively high or low local concentrations, ensure sufficient contact of the reactants, improve the reaction conversion rate, and at the same time, facilitate uniform contact between the chlorosilane compound and the difluorophosphate silyl ester compound, thereby enhancing the protective effect of the chlorosilane compound on the difluorophosphate silyl ester compound.

[0035] In one embodiment, in step S2, the chlorosilane compound reacts with the difluorophosphate in an inert gas atmosphere, which eliminates air moisture, reduces the introduction of water molecules, and thus reduces the hydrolysis reaction of the difluorophosphate silane compound. In this embodiment, the inert gas may include at least one of nitrogen, argon, and helium, and is not limited thereto.

[0036] In one embodiment, in step S2, the reaction temperature of the chlorosilane compound with difluorophosphate is between -10°C and 40°C. Optionally, the reaction temperature of the chlorosilane compound with difluorophosphate can be any one or any two of -10°C, -5°C, 0°C, 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, and 40°C, and is not limited herein. In this embodiment, when the reaction temperature is greater than 40°C, the reaction of the chlorosilane compound with difluorophosphate tends to compete with the reaction of the chlorosilane compound with water. The chlorosilane compound preferentially reacts with difluorophosphate to form difluorophosphate silyl ester compounds, and the difluorophosphate silyl ester compounds preferentially undergo hydrolysis, resulting in a decrease in the yield of difluorophosphate silyl ester compounds. When the reaction temperature is less than -10°C, the reaction energy consumption tends to increase, and the reaction rate and reaction conversion rate decrease.

[0037] In one embodiment, in step S2, the reaction time between the chlorosilane compound and difluorophosphate is 0.25 h to 10 h. Optionally, the reaction time between the chlorosilane compound and difluorophosphate can be any one or any two of 0.25 h, 0.5 h, 1 h, 3 h, 5 h, 8 h, 10 h, etc., and is not limited herein. In this embodiment, controlling the reaction time within the above range ensures the reaction conversion rate while reducing time and energy costs.

[0038] Because the reaction system is simple, consisting of only two reactants, the post-reaction system is also relatively simple, mainly containing the target product, excess chlorosilane compounds, MCl, and a small amount of residual difluorophosphate. The simple composition of the post-reaction system simplifies post-processing steps, making the reaction more suitable for industrial production.

[0039] In one embodiment, the difluorophosphate is dehydrated before use. This reduces the introduction of water molecules, thereby reducing the hydrolysis reaction of difluorophosphate silicates.

[0040] In one embodiment, the dehydration operation includes the following steps: adding difluorophosphate to a dry reaction vessel, then adding an inert solvent, stirring and mixing under nitrogen protection, then slowly adding thionyl chloride dropwise, controlling the temperature at 10-30°C during the dropwise addition, raising the temperature to 30-70°C after the dropwise addition is complete, reacting for 1-4 hours, and after the reaction is complete, removing the inert solvent and excess thionyl chloride by vacuum distillation to obtain dry difluorophosphate solid. In one embodiment, the dehydration operation satisfies at least one of the following: (1) The mass of the inert solvent is 2-6 times the mass of the difluorophosphate; (2) The inert solvent includes at least one of ethyl methyl carbonate and dichloromethane; (3) The molar ratio of thionyl chloride to difluorophosphate is (1.2-2.0):1.

[0041] The commonly used drying method is vacuum drying for dehydration. However, this method is affected by temperature, vacuum level, and time. Maintaining high temperature and high vacuum for extended periods is energy-intensive, and its effectiveness in removing crystal water or deeply adsorbed water is limited. Compared to vacuum drying, thionyl chloride dehydration offers advantages such as rapid reaction, thorough dehydration, and easily volatile and separable byproducts. However, thionyl chloride itself is highly corrosive, and the dehydration process generates intense heat, producing acidic gases that corrode equipment and lead to elevated metal ion levels.

[0042] In one embodiment, the purification process specifically includes: S31. Filter the mixture to obtain the filtrate; S32. The filtrate is subjected to vacuum distillation to remove chlorosilane compounds from the filtrate, yielding difluorophosphate silane compounds.

[0043] In this embodiment, filtration of the mixture removes inorganic salts insoluble in chlorosilane compounds, primarily difluorophosphate and MCl. Since chlorosilane compounds are in excess, the MCl content mainly depends on the difluorophosphate content. When the difluorophosphate content is the same, the MCl content is higher in this application compared to related technologies with smaller amounts of chlorosilanes. Therefore, filtration removes MCl first, resulting in a filtrate containing only the target product and excess chlorosilane compounds, simplifying the composition and facilitating subsequent processing. Furthermore, because the boiling points of chlorosilane compounds and the target product differ significantly, the target product can be obtained through simple vacuum distillation. This avoids cumbersome operations and the risk of water introduction leading to hydrolysis of the target product, which is a concern with other post-processing methods. More importantly, distillation of the target product solves the problem of increased metal ion content in the product caused by dehydration with thionyl chloride.

[0044] In one embodiment, the temperature of the vacuum distillation process is 30°C-70°C, and / or the vacuum degree of the vacuum distillation process is -0.09 MPa to -0.01 MPa, which is beneficial for further removal of chlorosilane compounds. Optionally, the temperature of the vacuum distillation process can be any one or any two of 30°C, 40°C, 50°C, 60°C, 70°C, etc., without limitation; the vacuum degree of the vacuum distillation process can be any one or any two of -0.09 MPa, -0.07 MPa, -0.05 MPa, -0.03 MPa, -0.02 MPa, -0.01 MPa, etc., without limitation.

[0045] This application also provides a difluorophosphate silicon ester compound, which is prepared by the preparation method described above.

[0046] In one embodiment, the difluorophosphate silane compound includes at least one of the following compounds: , , , , .

[0047] The above solution will be further explained below with reference to specific embodiments. The embodiments of this application are described in detail below: Example 1 1. Preparation of difluorophosphate silicon ester compounds (1) Provide a chlorosilane compound of formula (1-1) and sodium difluorophosphate, wherein the molar ratio of the chlorosilane compound to sodium difluorophosphate is 3:1; (2) Under a nitrogen atmosphere, chlorosilane compounds were reacted with sodium difluorophosphate at 25°C for 0.5 h to obtain a mixture containing difluorophosphate silane compounds; (3) Filter the mixture to obtain the filtrate; (4) The filtrate was subjected to vacuum distillation at 50℃ and a vacuum degree of -0.05 MPa to obtain difluorophosphate silicon ester compounds. The structural formula of the difluorophosphate silicon ester compounds is as follows:

[0048] The preparation methods of the difluorophosphate silicon ester compounds in Examples 2-21 and Comparative Examples 1-2 differ from those in Example 1 in that the types of reactants and reaction parameters are different, as shown in Table 1. Table 1

[0049] Test methods (1) Purity testing methods The purity of the products of Examples 1-21 and Comparative Examples 1-2 was determined by gas chromatography. Specifically, acetonitrile was used as the solvent, a gas chromatograph equipped with an FID detector was used, the injection port temperature was 120°C, the detector temperature was 150°C, the column temperature program was (initial 50°C, hold for 1 min, increase to 120°C at 5°C / min, hold for 1 min), and the column flow rate was 1 mL / min.

[0050] (2) Methods for testing yield After the reaction was completed, the insoluble matter in the mixture was taken, washed with solvents such as dichloromethane or acetonitrile, and the ratio of difluorophosphate to chloride ions in the insoluble matter was determined by IC (ion chromatography) method, so as to calculate the yield of difluorophosphate silicon ester compounds in Examples 1-21 and Comparative Examples 1-2.

[0051] The test results are shown in Table 2 above.

[0052] Table 2

[0053] Figure 1 , Figure 2 and Figure 3 The NMR spectra of the product in Example 1 are shown below: 19F NMR, 31P NMR, and 1H NMR. The spectra show a doublet near δ = -78 ppm in the 19F spectrum, a triplet near δ = -20 ppm in the 31P spectrum, and a singlet near δ = 0.3 ppm in the 1H spectrum, which is a -CH3 peak connected to Si. According to the principles of nuclear magnetic resonance coupling and splitting, the spin / spin coupling between adjacent nuclei and the resonant nucleus causes the resonant frequency to split. The number of split peaks is equal to the number of adjacent nuclei plus one, i.e., (n+1). The intensity ratio of the split peaks is the coefficient of the binomial expansion (a+b)^n, and the coupling constant J of different nuclei is equal. For difluorophosphate silicon ester, the coupling result of two F nuclei and one phosphorus nucleus should cause the 31P spectrum to split into a triplet and the 19F spectrum to split into a doublet, with the same coupling constant. The above graphs confirm that the product of Example 1 was successfully synthesized.

[0054] Figure 4 , Figure 5 and Figure 6 The NMR spectra of the product from Example 2 are shown below: 19F NMR, 31P NMR, and 1H NMR. In the 19F spectrum, a doublet peak appears near δ = -81 ppm. In the 31P spectrum, a triplet peak appears near δ = -29 ppm. In the 1H spectrum, a singlet peak appears near δ = 0.3 ppm, representing a -CH3 peak connected to Si, and two sets of quartets appear near δ = 6.0 and δ = 5.8, representing -CH=CH2 peaks connected to Si. These spectra confirm the successful synthesis of the product from Example 2.

[0055] Figure 7 , Figure 8 and Figure 9The NMR spectra of the product from Example 3 are shown below: 19F NMR, 31P NMR, and 1H NMR. In the 19F spectrum, a double strong peak appears near δ = -82 ppm. In the 31P spectrum, a triple strong peak appears near δ = -29 ppm. In the 1H spectrum, two sets of peaks appear near δ = 1 ppm, which are -CH2-CH3 peaks connected to Si. These spectra confirm the successful synthesis of the product from Example 3.

[0056] Figure 10 , Figure 11 and Figure 12 The NMR spectra of the product from Example 4 are shown below: 19F NMR, 31P NMR, and 1H NMR. In the 19F spectrum, a double strong peak appears near δ = -81 ppm. In the 31P spectrum, a triple strong peak appears near δ = -30 ppm. In the 1H spectrum, a single peak appears near δ = 0 ppm, which is the -CH3 peak connected to Si, and two sets of peaks appear near δ = 7 ppm, which are the -C6H5 peaks connected to Si. These spectra confirm the successful synthesis of the product from Example 4.

[0057] As shown in Table 2, the yields of difluorophosphate silicon ester compounds prepared in Examples 1 to 21 were improved compared to Comparative Examples 1-2. This indicates that by setting the molar ratio of chlorosilane compounds to difluorophosphate to be greater than or equal to 2, and controlling the reaction temperature to be less than or equal to 40°C, the generated difluorophosphate silicon ester compounds are less prone to hydrolysis, thereby improving the conversion rate and yield of the difluorophosphate silicon ester compounds.

[0058] A comparison of Examples 1 to 19, Example 21 and Example 20 shows that setting the molar ratio of chlorosilane compounds to difluorophosphate to (2-5):1 can improve the yield of difluorophosphate silane compounds while ensuring that the content of chlorosilane compounds in the mixture is not excessive, reducing the difficulty of subsequent purification of difluorophosphate silane compounds and improving the purity of difluorophosphate silane compounds.

[0059] As can be seen from the comparison between Example 1 and Example 17, the reaction of chlorosilane compounds with difluorophosphate in an inert gas atmosphere can eliminate air moisture, reduce the introduction of water molecules, thereby reducing the hydrolysis reaction of difluorophosphate silicon ester compounds and further improving the yield of difluorophosphate silicon ester compounds.

[0060] The embodiments of the present invention have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of the present invention. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A method for preparing a difluorophosphate silicon ester compound, characterized in that, include: A chlorosilane compound and a difluorophosphate are provided, wherein the molar ratio of the chlorosilane compound to the difluorophosphate is greater than or equal to 2; The chlorosilane compound is reacted with the difluorophosphate at a temperature of less than or equal to 40°C to obtain a mixture containing the difluorophosphate silyl ester compound; The mixture was purified to obtain the difluorophosphate silicon ester compound; The structure of the difluorophosphate silyl ester compound is shown in formula (1), the structure of the chlorosilane compound is shown in formula (2), and the structure of the difluorophosphate is shown in formula (3). Equation (1); Equation (2); Equation (3); R1, R2, and R3 are each independently selected from at least one of C1-C10 alkyl, C2-C10 alkenyl, C2-C10 alkynyl, C1-C10 alkoxy, and C6-C20 aromatic groups; M is selected from at least one of sodium ion, potassium ion, and ammonium ion.

2. The method for preparing difluorophosphate silicon ester compounds according to claim 1, characterized in that, The molar ratio of the chlorosilane compound to the difluorophosphate is (2-5):

1.

3. The method for preparing difluorophosphate silicon ester compounds according to claim 1 or 2, characterized in that, R1, R2, and R3 are each independently selected from at least one of the following: C1-C5 alkyl, C2-C5 alkenyl, C2-C5 alkynyl, C1-C5 alkoxy, and C6-C10 aromatic groups.

4. The method for preparing difluorophosphate silicon ester compounds according to claim 3, characterized in that, R1, R2, and R3 are each independently selected from at least one of C1-C2 alkyl, vinyl, or benzene ring groups.

5. The method for preparing the difluorophosphate silicon ester compound according to claim 1 or 2, characterized in that, The difluorophosphate includes at least one of sodium difluorophosphate, ammonium difluorophosphate, and potassium difluorophosphate; and / or The chlorosilane compounds include at least one of the following compounds: , , , , ; and / or The difluorophosphate silicate compound includes at least one of the following compounds: 、 、 、 、 。 6. The method for preparing the difluorophosphate silicon ester compound according to claim 1 or 2, characterized in that, The step of reacting the chlorosilane compound with the difluorophosphate at a temperature of less than or equal to 40°C to obtain a mixture containing the difluorophosphate silyl ester compound satisfies at least one of the following conditions: The chlorosilane compound reacts with the difluorophosphate under stirring conditions; The chlorosilane compound reacts with the difluorophosphate in an inert gas atmosphere; The reaction temperature between the chlorosilane compound and the difluorophosphate is -10°C to 40°C. The reaction time between the chlorosilane compound and the difluorophosphate is 0.25 h to 10 h.

7. The method for preparing difluorophosphate silicon ester compounds according to claim 1, characterized in that, The difluorophosphate is dehydrated before use.

8. The method for preparing difluorophosphate silicon ester compounds according to claim 7, characterized in that, The dehydration operation includes the following steps: adding difluorophosphate to a dry reaction vessel, then adding an inert solvent, stirring and mixing under nitrogen protection, then slowly adding thionyl chloride dropwise, controlling the temperature at 10~30°C during the dropwise addition, raising the temperature to 30-70°C after the dropwise addition is complete, reacting for 1-4 hours, and after the reaction is complete, removing the inert solvent and excess thionyl chloride by vacuum distillation to obtain dry difluorophosphate solid.

9. The method for preparing difluorophosphate silicon ester compounds according to claim 8, characterized in that, The dehydration operation must satisfy at least one of the following: (1) The mass of the inert solvent is 2-6 times the mass of the difluorophosphate; (2) The inert solvent includes at least one of ethyl methyl carbonate and dichloromethane; (3) The molar ratio of thionyl chloride to difluorophosphate is (1.2-2.0):

1.

10. The method for preparing the difluorophosphate silicon ester compound according to any one of claims 1, 2, or 7-9, characterized in that, The purification process specifically includes the following steps: The mixture is filtered to obtain a filtrate; The filtrate is subjected to vacuum distillation to remove the chlorosilane compounds from the filtrate, thereby obtaining the difluorophosphate silane compounds.

11. The method for preparing the difluorophosphate silicon ester compound according to claim 10, characterized in that, The temperature of the vacuum distillation process is 30℃-70℃, and / or the vacuum degree of the vacuum distillation process is -0.09Mpa to -0.01Mpa.

12. A difluorophosphate silicon ester compound, characterized in that, The difluorophosphate silicon ester compound is prepared by the preparation method according to any one of claims 1-11; the difluorophosphate silicon ester compound includes at least one of the following compounds: 、 、 、 、 。

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