Preparation method of hydrofluoroether compound and electrolyte

Abstract

In order to solve the problems that raw materials are expensive, explosive and highly toxic in a synthetic method of a fluoroether compound in the prior art, the invention provides a preparation method of a hydrofluoroether compound and an electrolyte, the preparation method of the hydrofluoroether compound comprises the following steps: S1, mixing a diol compound as shown in a formula 1, sulfonyl chloride, an inorganic base and a first solvent to obtain a mixed solution; reacting to obtain binary sulfonate; hO-R1-OH is shown in the formula 1, R1 is selected from a carbon chain containing O or S atoms, and the number of the O or S atoms is larger than or equal to 1; s2, mixing the binary sulfonate, fluoride salt and a second solvent, and reacting to obtain a hydrofluoroether compound as shown in a formula 2; the second solvent is a diol solvent; f-R1-F is represented by formula 2.

Description

Technical Field

[0001] The invention belongs to the technical field of organic fluorine chemistry, and in particular relates to a preparation method of a hydrofluoroether compound and an electrolyte. Background Art

[0002] The electrolyte used in existing lithium-ion batteries is generally ethylene carbonate (EC), ethyl methyl carbonate (EMC), dimethyl carbonate (DMC), diethyl carbonate (DEC) and the like as the main solvent, and lithium hexafluorophosphate is used as the lithium salt and a certain amount of additives are added to prepare the electrolyte. This type of electrolyte can form a relatively stable solid electrolyte membrane (SEI) on the graphite negative electrode, which can protect the graphite negative electrode from being peeled off during the cycle, thus achieving good cycle stability. At the same time, the electrolyte has a moderate oxidation resistance potential and is relatively stable to positive electrode materials such as lithium iron phosphate, lithium nickel cobalt manganese oxide, lithium cobalt oxide, and lithium manganese oxide, thus making it play a wide role in the field of lithium-ion batteries.

[0003] With the high demand for battery electrical performance, it is necessary to use a negative electrode material with a large capacity or a non-aqueous electrolyte with excellent electrochemical stability to improve the energy density of the battery. CN112382792A reported a monofluoroether with Li-F and Li-O tridentate coordination chemistry as an electrolyte solvent. The monofluoro substituent (-CH2F) in the solvent molecule is different from difluoro (-CHF2) and trifluoro (-CF3), which improves the ionic conductivity of the electrolyte without reducing the oxidative stability. Moreover, the electrolyte solution containing the monofluoroether solvent has a wide temperature range (i.e., from −60 °C to +60 °C) and a high charge / discharge rate (e.g., at 17.5 mA cm −2 It shows good compatibility with the positive and negative electrodes (when used), and the use of this electrolyte solvent greatly improves the battery energy density.

[0004] There are two types of synthesis methods for the above-mentioned monofluoroether electrolyte additives: the first type is that monofluoroalcohols or monofluorothiols are obtained by single-step or multi-step Williamson ether synthesis, but these preparation methods all require highly toxic monofluoroethanol or monofluorohalogenated substances, and the steps are complicated. The second type is the direct deoxyfluorination of heteroatom-containing diols. This method requires the use of explosive fluorination reagents DAST and BAST, and such reagents are expensive and have a relatively low yield. They are not applicable to diols containing multiple heteroatoms or longer fatty chains. Therefore, it is necessary to design a synthesis method suitable for the industrial production of bilateral monofluoroether compounds, which has solved the problems of expensive, explosive, and highly toxic raw materials in existing synthesis methods. Summary of the invention

[0005] Aiming at the problems of expensive, explosive and highly toxic raw materials in the synthesis method of fluoroether compounds in the prior art, the present invention provides a preparation method of hydrofluoroether compounds and an electrolyte.

[0006] The technical solution adopted by the present invention to solve the above technical problems is as follows: In a first aspect, the present invention provides a method for preparing a hydrofluoroether compound, comprising the following steps: S1, mixing the diol compound represented by formula 1, sulfonyl chloride, an inorganic base, and a first solvent to react to obtain a disulfonate; HO-R1-OH Formula 1, Wherein, R1 is selected from a carbon chain containing O or S atoms, and the number of O or S atoms is greater than or equal to 1; S2, mixing the disulfonate, fluoride salt and a second solvent, and reacting to obtain a hydrofluoroether compound represented by Formula 2; the second solvent is a glycol solvent; F-R1-F formula 2.

[0007] Optionally, the glycol solvent includes one or more of ethylene glycol, propylene glycol, hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and polyethylene glycol. Optionally, the mass ratio of the disulfonic acid ester to the diol solvent is 1:(2-10); And / or, the molar ratio of the disulfonate to the fluoride salt is 1:(1-15). Optionally, the fluoride salt includes one or more of potassium fluoride, sodium fluoride, cesium fluoride, silver fluoride, copper fluoride, and potassium bifluoride. Optionally, the molar ratio of the diol compound to the inorganic base is 1:(1-5); and / or, the molar ratio of the diol compound to the sulfonyl chloride is 1:(1-5); and / or, the mass ratio of the diol compound to the first solvent is 1:(1-15); And / or, the mass ratio of the first solvent to the sulfonyl chloride is 1:(1-5). Optionally, the sulfonyl chloride includes one or more selected from methylsulfonyl chloride, ethylsulfonyl chloride, benzenesulfonyl chloride, p-toluenesulfonyl chloride, and p-nitrobenzenesulfonyl chloride; and / or, the first solvent comprises one or more of tetrahydrofuran, ether, dioxane, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene dichloride, and dichloromethane; And / or, the inorganic base includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

[0008] Optionally, in S1, the reaction temperature is -20-80 °C, and the reaction time is 2-48 h.

[0009] In S2, the reaction temperature is 60-180° C., and the reaction time is 2-48 h. Optionally, in S1, the diol compound shown in Formula 1, an inorganic base and a first solvent are mixed to obtain a mixed solution, and then sulfonyl chloride is added dropwise to the mixed solution at -20~5°C. After the sulfonyl chloride is added dropwise, a reaction solution is obtained, and the reaction solution is heated to 5~80°C for reaction to obtain a disulfonate.

[0010] In a second aspect, the present invention provides an electrolyte comprising a hydrofluoroether compound prepared by the method for preparing a hydrofluoroether compound as described in any one of the above.

[0011] In the present invention, in the first aspect, a hydrofluoroether compound is synthesized by using a diol compound, a sulfonyl chloride and a fluoride salt through a two-step reaction. The raw materials used are cheap and safe, the synthesis method is simple, and it is suitable for industrial production. The nuclear magnetic hydrogen spectrum purity of the product during the reaction is ≥99%, and the yield of the final product hydrofluoroether reaches 80% to 95%. In the preparation method, the metal ions in the fluoride salt are coordinated by using a diol solvent to form a complex, reduce the reaction energy barrier, and make the sulfonate on both sides of the disulfonate leave for fluorination, thereby obtaining the hydrofluoroether compound of the present invention. At the same time, the diol solvent allows the preparation process of the hydrofluoroether compound to be carried out in a homogeneous phase.

[0012] Secondly, the hydrofluoroether compound obtained by the preparation method of the present invention can be used as an electrolyte solvent or additive to improve the ionic conductivity of the electrolyte without reducing the oxidation stability, thereby improving the energy density of the battery. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is the hydrogen spectrum of the dibasic sulfonate compound in Example 1 of the present invention; Figure 2 is the hydrogen spectrum of the hydrofluoroether compound in Example 1 of the present invention; Figure 3 : is the fluorine spectrum of the hydrofluoroether compound in Example 1 of the present invention. DETAILED DESCRIPTION

[0013] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0014] An embodiment of the present invention provides a method for preparing a hydrofluoroether compound as described in any one of the above items, comprising the following steps: S1, mixing the diol compound represented by formula 1, sulfonyl chloride, an inorganic base, and a first solvent to react to obtain a disulfonate; HO-R1-OH Formula 1, Wherein, R1 is selected from a carbon chain containing O or S atoms, and the number of O or S atoms is greater than or equal to 1; S2, mixing the disulfonate, fluoride salt and a second solvent, and reacting to obtain a hydrofluoroether compound represented by Formula 2; the second solvent is a glycol solvent; F-R1-F formula 2.

[0015] In the present invention, a hydrofluoroether compound is synthesized by using a diol compound, sulfonyl chloride and a fluoride salt through a two-step reaction. The raw materials used are cheap and safe, the synthesis method is simple, and it is suitable for industrial production. The nuclear magnetic hydrogen spectrum purity of the product during the reaction is ≥99%, and the yield of the final product hydrofluoroether reaches 80% to 95%. In the preparation method, the metal ions in the fluoride salt are coordinated by using a diol solvent to form a complex, reduce the reaction energy barrier, and make the sulfonate on both sides of the disulfonate leave for fluorination, thereby obtaining the hydrofluoroether compound in the present invention. At the same time, the diol solvent allows the preparation process of the hydrofluoroether compound to be carried out in a homogeneous phase.

[0016] In some embodiments, the diol solvent includes one or more of ethylene glycol, propylene glycol, hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and polyethylene glycol. By selecting the above diol solvent, the reaction in step S2 is carried out in a homogeneous phase, and the above diol solvent coordinates the metal ions in the fluoride salt to form a complex, thereby reducing the reaction energy barrier to obtain a reaction product, a hydrofluoroether compound.

[0017] In some embodiments, the mass ratio of the disulfonate to the diol solvent is 1:(2-10); And / or, the molar ratio of the disulfonate to the fluoride salt is 1:(1-15).

[0018] Specifically, the mass ratio of the disulfonic acid ester to the diol solvent includes, but is not limited to, 1:10, 1:9, 1:8, 1:7, 1:6, 1:5, 1:4, 1:3 or 1:2. The molar ratio of the disulfonic acid ester to the fluoride salt includes, but is not limited to, 1:1, 1:3, 1:6, 1:9, 1:12 or 1:15. By limiting the mass or amount of the disulfonic acid ester, the diol solvent and the fluoride salt, the diol solvent and the fluoride salt can be coordinated to obtain a complex, and the entire reaction is carried out in a homogeneous phase. In some embodiments, the fluoride salt includes one or more of potassium fluoride, sodium fluoride, cesium fluoride, silver fluoride, copper fluoride, and potassium bifluoride. By selecting the above fluoride salts to fluorinate the disulfonate, the entire reaction is simple, safe, and suitable for industrial production. In some embodiments, the molar ratio of the diol compound to the inorganic base is 1:(1-5); and / or, the molar ratio of the diol compound to the sulfonyl chloride is 1:(1-5); and / or, the mass ratio of the diol compound to the first solvent is 1:(1-15); And / or, the mass ratio of the first solvent to the sulfonyl chloride is 1:(1-5).

[0019] The yield of the disulfonate is improved by limiting the molar ratio of the diol compound, the inorganic base and the sulfonyl chloride. In step S1, the H-NMR spectrum purity of the disulfonate is ≥99%, and the yield of the disulfonate is 95%-98%. In some embodiments, the sulfonyl chloride comprises one or more selected from the group consisting of methanesulfonyl chloride, ethylsulfonyl chloride, benzenesulfonyl chloride, p-toluenesulfonyl chloride, and p-nitrobenzenesulfonyl chloride; and / or, the first solvent comprises one or more of tetrahydrofuran, ether, dioxane, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene dichloride, and dichloromethane; And / or, the inorganic base includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide. Specifically, the inorganic base is dissolved in water and then mixed with the diol compound and sulfonyl chloride. In some embodiments, in S1, the reaction temperature is -20-80 °C, and the reaction time is 2-48 h.

[0020] In S2, the reaction temperature is 60-180° C., and the reaction time is 2-48 h.

[0021] In some embodiments, in S1, the diol compound represented by Formula 1, an inorganic base and a first solvent are mixed to obtain a mixed solution, and then sulfonyl chloride is added dropwise to the mixed solution at -20 to 5°C. After the sulfonyl chloride is added dropwise, a reaction solution is obtained, and the reaction solution is heated to 5 to 80°C for reaction to obtain a disulfonate.

[0022] An embodiment of the present invention further provides an electrolyte, comprising a hydrofluoroether compound prepared by any of the above methods for preparing a hydrofluoroether compound.

[0023] The hydrofluoroether compound obtained by the preparation method of the present invention can be used as an electrolyte solvent or additive to improve the ionic conductivity of the electrolyte without reducing the oxidation stability, thereby improving the energy density of the battery.

[0024] The present invention is further described below by way of examples.

[0025] Example 1 This example is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention.

[0026] S1, add 400 g (10 mol) of sodium hydroxide, 3000 g of water, 1500 g of tetrahydrofuran, 424 g (4 mol) of diol compound diethylene glycol to a 10 L three-necked flask, cool to 0-5 ° C, then drop 1900 g (10 mol) of p-toluenesulfonyl chloride (dissolved in 2800 g of tetrahydrofuran), keep warm at 0-10 ° C for reaction, evaporate tetrahydrofuran after the reaction, filter to obtain solid, and wash the solid with water. Use ethanol for recrystallization once, dry to obtain 1570 g of 2,2′-oxybis-1,1′-bis(4-methylbenzenesulfonate)ethanol, with a yield of 95%. The NMR spectrum is as follows Figure 1 . ( 1 H NMR (400 MHz, CDCl3) δ 2.45 (s, 6H), 3.61 (t, J = 4.0 Hz, 4 H), 4.09 (t, J = 4.0 Hz, 4 H), 7.35 (d, J = 4.0 Hz, 4H), 7.78 (d, J = 4.0 Hz, 4 H) ppm.

[0027] S2, 3500 g of ethylene glycol, 1010 g (2.4 mol) of 2,2′-oxybis-1,1′-bis(4-methylbenzenesulfonate)ethanol, and 900 g (15.5 mol) of potassium fluoride were added to a 5 L bottle, and the mixture was kept at 80°C for reaction. After the reaction, 242 g of the product was extracted under reduced pressure, with a GC purity of 99.1% and a yield of 90%. The NMR spectrum is shown in Figure 2 , 3 . ( 1 H NMR (400 MHz, DMSO- d 6) δ 3.65 (t, J =4.0 Hz, 2 H), 3.73 (t, J = 4.0 Hz, 2 H), 4.47 (t, J = 4.0 Hz, 2 H), 4.59 (t, J =4.0 Hz, 2 H) ppm; 19 F NMR (400 MHz, DMSO-d 6) δ -222.04 (s, 2 F) ppm) Example 2 Example 2 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention.

[0028] S1, add 800 g (20 mol) of sodium hydroxide, 3000 g of water, 1500 g of tetrahydrofuran, 600 g (4 mol) of diol compound triethylene glycol to a 10 L three-necked flask, cool to 0-5 ° C, then drop 1900 g (10 mol) of p-toluenesulfonyl chloride (dissolved in 2800 g of tetrahydrofuran), keep warm at 0-10 ° C for reaction, evaporate tetrahydrofuran after the reaction, filter to obtain solid, and wash the solid with water. Recrystallize once with ethanol and dry to obtain 1780 g of (ethane-1,2-diylbis(oxygen))bis(ethane-2,1-diyl)bis(4-methylbenzenesulfonate), with a yield of 97%.

[0029] S2, 4000 g of hexanediol, 1120 g (2.4 mol) of (ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl)bis(4-methylbenzenesulfonate), and 600 g (14 mol) of sodium fluoride were added into a 5 L bottle, and the mixture was kept at 70°C for reaction. After the reaction, 311 g of the product was recovered under reduced pressure, with a GC purity of 99.5% and a yield of 82%.

[0030] Example 3 Example 3 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above-mentioned Example 1, and the difference is that: in S2, the diol solvent is triethylene glycol, and the yield is 90%.

[0031] Example 4 Example 4 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above-mentioned Example 1, and the difference is that: in S1, the diol compound is tetraethylene glycol, and the yield is 86%.

[0032] Example 5 Example 5 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the fluoride salt is copper fluoride, and the yield is 80%.

[0033] Example 6 Example 6 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above-mentioned Example 1, and the difference is that: in S2, the fluoride salt is potassium bifluoride, and the yield is 88%.

[0034] Example 7 Example 7 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of ethylene glycol added is 10100 g, and the yield is 90%.

[0035] Example 8 Example 8 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of ethylene glycol added is 5050 g, and the yield is 93%.

[0036] Example 9 Example 9 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of ethylene glycol added is 2020 g, and the yield is 80%.

[0037] Example 10 Example 10 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of ethylene glycol added is 1010 g, and the yield is 65%.

[0038] Embodiment 11 Example 11 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of ethylene glycol added is 11110 g, and the yield is 90%.

[0039] Example 12 Example 12 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of potassium fluoride added is 139.2 g (2.4 mol), and the yield is 85%.

[0040] Embodiment 13 Example 13 is used to illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in the above Example 1, except that: in S2, the amount of potassium fluoride added is 2088 g (36 mol), and the yield is 90%.

[0041] Comparative Example 1 Comparative Example 1 is used to compare and illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in Example 1, except that: In S2, 350 g of dimethyl sulfoxide, 101 g (0.24 mol) of 2,2′-oxybis-1,1′-bis(4-methylbenzenesulfonate)ethanol, and 90 g (1.6 mol) of potassium fluoride were added to a 5 L bottle and kept at 80°C for reaction. After the reaction was completed, the solid was filtered and sampled for measurement. 19 No product was detected by F NMR and GC-MS.

[0042] Comparative Example 2 Comparative Example 2 is used to compare and illustrate the hydrofluoroether compound and the preparation method thereof disclosed in the present invention, and includes most of the operating steps in Example 2, except that: In S2, 400 g of acetonitrile, 112 g (0.24 mol) of (ethane-1,2-diylbis(oxy))bis(ethane-2,1-diyl)bis(4-methylbenzenesulfonate), and 60 g (1.4 mol) of sodium fluoride were added to a 5 L bottle and the reaction was carried out at 70°C. After the reaction was completed, the solid was filtered and sampled for measurement. 19 No product was detected by F NMR and GC-MS.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing a hydrofluoroether compound, characterized in that: The following steps are involved: S1, mixing the diol compound represented by formula 1, sulfonyl chloride, an inorganic base, and a first solvent to react to obtain a disulfonate; HO-R1-OH Formula 1, Wherein, R1 is selected from a carbon chain containing O or S atoms, and the number of O or S atoms is greater than or equal to 1; S2, mixing the disulfonate, fluoride salt and a second solvent, and reacting to obtain a hydrofluoroether compound represented by Formula 2; the second solvent is a glycol solvent; F-R1-F formula 2.

2. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: The glycol solvent includes one or more of ethylene glycol, propylene glycol, hexylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, pentaethylene glycol, and polyethylene glycol.

3. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: The R1 is or , where n is an integer from 1 to 5.

4. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: The mass ratio of the disulfonic acid ester to the diol solvent is 1:(2-10); And / or, the molar ratio of the disulfonate to the fluoride salt is 1:(1-15).

5. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: The fluoride salt includes one or more of potassium fluoride, sodium fluoride, cesium fluoride, silver fluoride, copper fluoride, and potassium bifluoride.

6. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: The molar ratio of the diol compound to the inorganic base is 1:(1-5); and / or, the molar ratio of the diol compound to the sulfonyl chloride is 1:(1-5); and / or, the mass ratio of the diol compound to the first solvent is 1:(1-15); And / or, the mass ratio of the first solvent to the sulfonyl chloride is 1:(1-5).

7. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: The sulfonyl chloride includes one or more selected from the group consisting of methylsulfonyl chloride, ethylsulfonyl chloride, benzenesulfonyl chloride, p-toluenesulfonyl chloride, and p-nitrobenzenesulfonyl chloride; and / or, the first solvent comprises one or more of tetrahydrofuran, ether, dioxane, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, ethylene dichloride, and dichloromethane; And / or, the inorganic base includes one or more of sodium hydroxide, potassium hydroxide, and lithium hydroxide.

8. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: In S1, the reaction temperature is -20-80 °C and the reaction time is 2-48 h; In S2, the reaction temperature is 60-180° C., and the reaction time is 2-48 h.

9. The method for preparing a hydrofluoroether compound according to claim 1, characterized in that: In S1, the diol compound represented by Formula 1, an inorganic base and a first solvent are mixed to obtain a mixed solution, and then sulfonyl chloride is added dropwise to the mixed solution at -20 to 5°C. After the sulfonyl chloride is added dropwise, a reaction solution is obtained, and the reaction solution is heated to 5 to 80°C for reaction to obtain a disulfonic acid ester.

10. An electrolyte, characterized in that: The invention comprises a hydrofluoroether compound prepared by the method for preparing a hydrofluoroether compound according to any one of claims 1 to 9.

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