Preparation method of fluorine-containing acetal compound

Abstract

The invention discloses a fluorine-containing acetal compound and a preparation method thereof. The preparation method comprises the following steps: catalyzing a fluoroalcohol compound to react with dimethoxymethane by using an acid to obtain a reaction crude product; and purifying the reaction crude product to obtain the fluorine-containing acetal compound. Wherein the structural formula of the fluorine-containing acetal compound is Rf-O-CH2-O-Rf, and Rf is selected from fluoroalkyl of which the carbon atom number is C1-C6. According to the method, the reaction efficiency and the conversion rate of the reaction are effectively improved by utilizing the acid to catalyze the reaction in a solvent-free system.

Description

Technical Field

[0001] This application relates to the field of chemical synthesis, and in particular to a method for preparing fluorinated acetals in a solvent-free system using acid catalysis. Background Technology

[0002] Fluorinated acetals can be used as electrolyte solutions or additives in lithium-ion batteries. However, current methods for preparing fluorinated acetals suffer from limitations such as limited method availability and low production efficiency. Summary of the Invention

[0003] To address at least one of the aforementioned problems, this application discloses a method for preparing fluorinated acetal compounds. The method involves reacting the raw materials in a solvent-free system using acid catalysis, resulting in a short reaction time, high reaction efficiency, and high raw material conversion rate.

[0004] The first aspect of this application provides a method for preparing a fluorinated acetal compound, the method comprising the following steps: reacting a fluorinated alcohol compound with dimethoxymethane using acid catalysis to obtain a crude reaction product; purifying the crude reaction product to obtain the fluorinated acetal compound; wherein the structural formula of the fluorinated acetal compound is shown in Formula I): Formula I); Among them, R f Selected from fluoroalkyl groups with C1 to C6 carbon atoms.

[0005] According to some embodiments of this application, the acid includes at least one of p-toluenesulfonic acid, trifluoroacetic acid, acetic acid, formic acid, concentrated sulfuric acid, or polyphosphoric acid.

[0006] According to some embodiments of this application, the molar ratio of the fluoroalcohol to the dimethoxymethane is (2-5):1.

[0007] According to some embodiments of this application, the mass ratio of the acid to the fluorinated alcohol compound is (0.01-0.1):1.

[0008] According to some embodiments of this application, the reaction of the fluoroalcohol compound with dimethoxymethane satisfies at least one of the following conditions: (1) the reaction temperature is 30℃-80℃; (2) the reaction time is 1h-16h.

[0009] According to some embodiments of this application, the purification operation includes separation and acid removal: using an organic solvent to remove the acid by extraction and layering; wherein the density of the organic solvent is less than 1 g / mL.

[0010] According to some embodiments of this application, the organic solvent is selected from at least one of petroleum ether, n-hexane, or ethyl acetate.

[0011] According to some embodiments of this application, the purification operation further includes distillation purification, wherein the distillation purification satisfies at least one of the following conditions: (1) the distillation temperature is 20℃-90℃; (2) the distillation pressure is 1mbar to 200mbar.

[0012] According to some embodiments of this application, R f The number of substituted fluorine atoms on each carbon atom is 0-3.

[0013] According to some embodiments of this application, the fluorinated acetal compound includes one or more of the following compounds: , , , , , , .

[0014] A second aspect of this application provides a fluorinated acetal compound, which is prepared by the above-described preparation method.

[0015] A third aspect of this application provides an electrolyte comprising the fluorinated acetal compounds described above.

[0016] A fourth aspect of this application provides a lithium-ion battery, wherein the lithium-ion battery uses the electrolyte described above.

[0017] The fifth aspect of this application provides a battery module comprising a plurality of lithium-ion batteries as described above, which are folded, stacked, or combined to form a battery module.

[0018] The sixth aspect of this application provides an electrical device, which includes a battery module as described above.

[0019] Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0020] The disclosure of this application will become more readily understood with reference to the accompanying drawings. It will be readily understood by those skilled in the art that these drawings are for illustrative purposes only and are not intended to limit the scope of protection of this application. Furthermore, similar numbers in the drawings are used to denote similar components, wherein: Figure 1 These are the proton NMR spectra of fluorinated acetal compounds shown in some embodiments of this application; Figure 2 These are carbon spectra of fluorinated acetal compounds shown in some embodiments of this application; Figure 3 This is the fluorine spectrum of fluorinated acetal compounds shown in some embodiments of this application. Detailed Implementation

[0021] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The terms “comprising” or “including” as used herein mean that an element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “and / or” or “and / or” as used herein include any and all combinations of one or more of the associated listed items. The terms “optionally” or “preferredly” as used herein may refer to embodiments that provide certain beneficial effects in certain circumstances, but this does not limit the scope to embodiments that have inferior technical effects or are unavailable, nor is it intended to exclude or limit the embodiments related to this application.

[0023] The numerical range disclosed in this application should be considered continuous, encompassing any value between the maximum and minimum values ​​defining the range. The maximum and / or minimum values ​​may or may not be included within the numerical range. Unless otherwise stated, the numerical range AB may include any combination of real numbers from A to B, as well as any subrange consisting of any two real numbers. For example, the numerical range 0-5 may include, but is not limited to, 1-4, 2-3, 2.3-2.8, etc.

[0024] The following describes some preferred embodiments of this application. It should be noted that the following description is for illustrative purposes only and is not intended to limit the scope of protection of this application. The steps involved in this application may be performed precisely in sequence, or various steps may be processed in reverse order or simultaneously. Furthermore, other operations may be added to these processes, or one or more steps may be removed from these processes.

[0025] The method for preparing fluorinated acetals provided in this application may include the following steps: reacting a fluorinated alcohol compound with dimethoxymethane using acid catalysis to obtain a crude reaction product; and purifying the crude reaction product to obtain the fluorinated acetal compound. The structural formula of the fluorinated acetal compound is shown in Formula 1): [Formula I] Formula I); Among them, R f Selected from fluoroalkyl groups with C1 to C6 carbon atoms.

[0026] The acid used as a catalyst in this application can be one or more inorganic or organic acids. Exemplarily, but not limitingly, the inorganic acid may be selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, polyphosphoric acid, hydrofluoric acid, perchloric acid, chlorosulfonic acid, pyrophosphoric acid, nitric acid, etc. The organic acid may be selected from one or more of acetic acid, benzenesulfonic acid, p-toluenesulfonic acid, methanesulfonic acid, formic acid, trifluoroacetic acid, oxalic acid, citric acid, succinic acid, trifluoromethanesulfonic acid, etc. Optionally or preferably, the acid may be at least one of p-toluenesulfonic acid, trifluoroacetic acid, acetic acid, formic acid, concentrated sulfuric acid, or polyphosphoric acid. Optionally or preferably, the acid may be polyphosphoric acid.

[0027] Polyphosphoric acid (PPA) is a moderately strong protic acid that efficiently protonates dimethoxymethane to produce methoxymethyl cations. Simultaneously, PPA activates the hydroxyl groups of fluorinated alcohols, promoting nucleophilic substitution / condensation reactions, thereby increasing the reaction rate and catalytic efficiency. Furthermore, since the reaction involves the production of water molecules, PPA also functions as a dehydrator, immediately removing the water generated in the reaction, disrupting the reversible reaction equilibrium, and significantly improving product yield. In addition, the fluorine atoms in fluorinated alcohols are highly electronegative, making the substrates and products sensitive to oxidation and substitution. PPA, however, has no strong oxidizing properties and will not trigger side reactions such as fluorine atom substitution, hydroxyl oxidation, or carbon-fluorine bond breaking, thus maintaining the structural integrity of the target product. Using PPA for catalysis also eliminates the need for high temperatures, avoiding the β-elimination reaction of fluorinated alcohols to form fluorinated alkenes due to high temperatures, and reducing excessive decomposition of dimethoxymethane (such as the formation of impurities like formaldehyde and methanol), resulting in high product purity. Furthermore, polyphosphoric acid is a viscous liquid with low volatility and no acid mist pollution, making it safer to handle than concentrated hydrochloric acid, hydrochloric acid, and hydrofluoric acid. After the reaction, it can be neutralized by dilution with water, and the product can be quickly separated by separation or filtration. Post-processing is simple and does not require complex acid recovery steps.

[0028] The fluorinated alcohols used in this application may be represented by R. f The general formula for -OH is used. R fThe compounds are selected from fluoroalkyl groups with 1 to 6 carbon atoms. For each carbon atom, the number of substituted fluorine atoms attached can be 0, 1, 2, or 3. This corresponds to unsubstituted, monofluorinated, polyfluorinated, and perfluorinated compounds, respectively. For example, a variation of the general formula of the fluoroalcohols can be F-(CH2). n -OH or R-CHF-OH. The former is a straight-chain structure, and the latter is a branched-chain structure, where R is an alkyl group. For example, another variation of the general formula of the fluoroalcohols can be C... m F p H q -OH, where m≥1, p≥2, p+q=2m+1. This represents a polyfluorinated alcohol with a saturated chain structure. For example, another variation of the general formula of the fluorinated alcohols can be C... m F 2m+1 -OH, m≥1. This represents a perfluoroalcohol.

[0029] The fluoroalcohol compounds can have a variety of choices based on the number of carbon atoms, the linkage mode, and the number of substituted fluorine atoms. As an exemplary but non-limiting illustration, the fluoroalcohol compounds used in this application may include, but are not limited to, one or more of the following: fluoromethanol, 2-fluoroethanol, 2,2-difluoroethanol, 2,2,2-trifluoroethanol, 3-fluoropropanol, 1-fluoro-2-propanol, 3,3,3-trifluoropropanol, tetrafluoropropanol, 1-fluoro-2-butanol, 2,2,3,3-tetrafluorobutanol, 2-trifluoromethyl-2-fluoroethanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, and hexafluorobutanol.

[0030] The molar ratio of the reactants in the above reaction, namely the fluoroalcohol compound and the dimethoxymethane, can be 2-5:1. For example, the molar ratio of the fluoroalcohol compound to the dimethoxymethane can be 2:1, 3:1, 4:1, 5:1, or any increase or decrease in the above molar ratios. Optionally or preferably, the molar ratio of the fluoroalcohol compound to the dimethoxymethane is 3:1. The mass ratio between the acid used for catalysis and the fluoroalcohol compound is (0.01-0.1):1. For example, the mass fraction of the acid in the total mass of the fluoroalcohol compound is 1wt%, 2wt%, 3wt%, 4wt%, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, or any mass fraction above, or any decrease in the above mass fractions. Optionally or preferably, the mass ratio between the acid used for catalysis and the fluoroalcohol compound is 0.03:1, 0.04:1, 0.05:1, or 0.09:1.

[0031] In some embodiments, the reaction between the above-mentioned fluorinated alcohols and dimethoxymethane can be carried out at a reaction temperature of 30°C-80°C. Optionally or preferably, the reaction temperature can be 40°C-70°C. Optionally or preferably, the reaction temperature can be 50°C-60°C. Optionally or preferably, the reaction temperature can be 60°C or 70°C. The reaction time between the above-mentioned fluorinated alcohols and dimethoxymethane can be 1h-16h. For example, 1h, 3h, 5h, 7h, 9h, 11h, 13h, 16h, etc. Optionally or preferably, the reaction time between the above-mentioned fluorinated alcohols and dimethoxymethane is 3h or 4h.

[0032] The crude product obtained after the above reaction is completed can be purified to obtain the final target product, namely the fluorinated acetal compound. In some embodiments, the purification operation may include separation and removal of acid, distillation purification, etc. The separation and removal of acid may be carried out by using an organic solvent to remove the acid through extraction and layering. The density of the organic solvent may be less than 1 g / mL. For example, the organic solvent may be selected from one or more of ethyl acetate, methyl tert-butyl ether, petroleum ether, diethyl ether, toluene, n-hexane, etc. When polyphosphoric acid is used as the acid, the reaction solution can be cooled to room temperature (or ice water) after the reaction is completed. After completion, a saturated sodium bicarbonate solution can be added to adjust the pH to 4-6. Then, the organic solvent (the amount added may be the same as the volume of the aqueous phase), stirred, allowed to stand and separate, and the upper organic phase is collected to complete the separation and removal of acid.

[0033] The distillation purification can be used to purify the final product from an organic phase containing water-soluble impurities. The distillation temperature for purification can be between 20°C and 90°C. For example, 20°C, 50°C, 70°C, or 90°C, or any value within this range. Optionally or preferably, the distillation temperature can be 40°C. The distillation pressure for purification can be from 1 mbar to 200 mbar. For example, 10 mbar, 50 mbar, 100 mbar, 150 mbar, 200 mbar, etc., or any value within this range. Optionally or preferably, the distillation pressure is 100 mbar or 140 mbar.

[0034] In some embodiments, the final product obtained is a fluorinated acetal compound, based on the selection of the fluorinated alcohol compound (e.g., R). f The choice of which may be at least a polyfluorinated substituted compound. For example, the fluorinated acetal may include one or more of the following compounds: , , , , , , ; The corresponding fluorinated alcohols are 2-fluoroethanol, 2,2-difluoroethanol, 2,2,2-trifluoroethanol, hexafluoroisopropanol, tetrafluoropropanol, 2,2,3,3,4,4,5,5-octafluoro-1-pentanol, or hexafluorobutanol.

[0035] The present application will be further described in detail below with reference to the embodiments. It should be noted that the following embodiments are for illustrative purposes only and are not intended to limit the scope of protection claimed in this application. Unless otherwise specified, the reagents, materials and instruments used are all commercially available products and can be obtained by purchase.

[0036] Example 1 - Synthesis and Preparation of Bis(2-fluoroethoxy)methane 51 g of 2-fluoroethanol (802 mmol) was added to a 500 mL reaction flask, followed by 20 g of dimethoxymethane (263 mmol) at room temperature. The mixture was cooled to 5 °C, and 2.58 g of polyphosphoric acid was slowly added dropwise. The mixture was then heated to 70 °C and reacted for 4 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with 150 mL of ethyl acetate, allowed to stand for separation, and the lower catalytic acid layer was removed. The supernatant crude product was collected and distilled under reduced pressure at 100 mbar at 40 °C to obtain 21 g of pure bis(2-fluoroethoxy)methane, a colorless liquid, with a yield of 57%. GC analysis showed a chemical purity of 99.7%; acidity was <1 ppm by titration; and chloride ion content was <1 ppm by ion chromatography.

[0037] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 4.70 (s, 2H), 4.61 – 4.51 (m, 2H), 4.49 – 4.36 (m, 2H), 3.81 – 3.73 (m, 2H), 3.73 – 3.65 (m, 2H). 13 C NMR (101MHz, Chloroform-d) δ 94.50, 80.98, 65.95. 19 F NMR (376 MHz, Chloroform-d) δ -224.08. For details, please refer to [reference needed]. Figures 1-3 The hydrogen, carbon, and fluorine spectra of the above products are shown respectively.

[0038] Example 2 - Synthesis and Preparation of Bis(2,2-Difluoroethoxy)methane 50 g of 2,2-difluoroethanol (611 mmol) was added to a 500 mL reaction flask, followed by 15.5 g of dimethoxymethane (204 mmol) at room temperature. The mixture was cooled to 5 °C, and 2.0 g of polyphosphoric acid was slowly added dropwise. The mixture was then heated to 60 °C and reacted for 5 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with 150 mL of ethyl acetate, allowed to stand for separation, and the lower catalytic acid layer was removed. The supernatant crude product was collected and distilled under reduced pressure at 140 mbar at 40 °C to obtain 17 g of pure bis(2,2-difluoroethoxy)methane as a colorless liquid, with a yield of 47%. GC analysis showed a chemical purity of 99.6%; acidity was <1 ppm by titration; and chloride ion content was <1 ppm by ion chromatography.

[0039] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 5.74-5.94 (m, 2H), 4.76 (s, 2H), 3.76 (m, 4H). 13 C NMR (101 MHz, Chloroform-d) δ 122.31, 95.80, 72.41. 19 F NMR (376MHz, Chloroform-d) δ -127.91.

[0040] Example 3 - Synthesis and Preparation of Bis(2,2,2-trifluoroethoxy)methane 51.2 g (513 mmol) of 2,2,2-trifluoroethanol was added to a 500 mL reaction flask, followed by 13.0 g (171 mmol) of dimethoxymethane at room temperature. The mixture was cooled to 5 °C, and 1.7 g of polyphosphoric acid was slowly added dropwise. The mixture was then heated to 60 °C and reacted for 4 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with 150 mL of ethyl acetate, allowed to stand for separation, and the lower catalytic acid layer was removed. The supernatant crude product was collected and distilled under reduced pressure at 40 °C and 140 mbar to obtain 18 g of pure bis(2,2,2-trifluoroethoxy)methane, a colorless liquid, with a yield of 50%. GC analysis showed a chemical purity of 99.6%; acidity was <1 ppm by titration; and chloride ion content was <1 ppm by ion chromatography.

[0041] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 4.71 (s, 2H), 3.99 – 3.88 (m, 4H). 13CNMR (101 MHz, Chloroform-d) δ 124.26, 95.74, 65.37. 19 F NMR (376 MHz, Chloroform-d) δ -74.50.

[0042] Example 4 - Synthesis and Preparation of Bis(2-fluoroethoxy)methane 51 g of 2-fluoroethanol (802 mmol) was added to a 500 mL reaction flask, followed by 20 g of dimethoxymethane (263 mmol) at room temperature. The mixture was cooled to 5 °C, and 4.8 g of acetic acid was slowly added dropwise. The mixture was then heated to 80 °C and reacted for 4 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with 150 mL of ethyl acetate, allowed to stand for separation, and the lower catalytic acid layer was removed. The supernatant crude product was collected and distilled under reduced pressure at 100 mbar at 40 °C to obtain 18 g of pure bis(2-fluoroethoxy)methane, a colorless liquid, with a yield of 48%. GC analysis showed a chemical purity of 99.6%; acidity was determined to be <1 ppm by titration; and chloride ion content was determined to be <1 ppm by ion chromatography.

[0043] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 4.70 (s, 2H), 4.61 – 4.51 (m, 2H), 4.49 – 4.36 (m, 2H), 3.81 – 3.73 (m, 2H), 3.73 – 3.65 (m, 2H). 13 C NMR (101MHz, Chloroform-d) δ 94.50, 80.98, 65.95. 19 F NMR (376 MHz, Chloroform-d) δ -224.08.

[0044] Example 5 - Synthesis and Preparation of Bis(2-fluoroethoxy)methane 51 g of 2-fluoroethanol (802 mmol) was added to a 500 mL reaction flask, followed by 20 g of dimethoxymethane (263 mmol) at room temperature. The mixture was cooled to 5 °C, and formic acid (2.1 g) was slowly added dropwise. The temperature was then raised to 80 °C and reacted for 3 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with 150 mL of ethyl acetate, allowed to stand for separation, and the lower catalytic acid layer was removed. The supernatant crude product was collected and distilled under reduced pressure at 100 mbar at 40 °C to obtain 19 g of pure bis(2-fluoroethoxy)methane, a colorless liquid, with a yield of 51%. GC analysis showed a chemical purity of 99.2%; acidity was <1 ppm by titration; and chloride ion content was <1 ppm by ion chromatography.

[0045] The proton NMR spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 4.70 (s, 2H), 4.61 – 4.51 (m, 2H), 4.49 – 4.36 (m, 2H), 3.81 – 3.73 (m, 2H), 3.73 – 3.65 (m, 2H). 13 C NMR (101MHz, Chloroform-d) δ 94.50, 80.98, 65.95. 19 F NMR (376 MHz, Chloroform-d) δ -224.08. Example 6 - Synthesis and preparation of bis[(1,1,1,3,3,3-hexafluoroisopropyl)oxy]methane Hexafluoroisopropanol (57.4 g, 342 mmol) was added to a 500 mL reaction flask, followed by dimethoxymethane (10 g, 131 mmol) at room temperature. The mixture was cooled to 5 °C, and polyphosphoric acid (2.5 g) was slowly added dropwise. The mixture was then heated to 60 °C and reacted for 5 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with ethyl acetate (150 mL), allowed to stand for separation, and the lower catalytic acid layer was removed. The supernatant crude product was collected and distilled under reduced pressure at 20 °C and 180 mbar to obtain 20 g of pure bis[(1,1,1,3,3,3-hexafluoroisopropyl)oxy]methane, a colorless liquid with a yield of 44%. GC analysis showed a chemical purity of 99.3%; acidity was <1 ppm by titration; and chloride ion content was <1 ppm by ion chromatography.

[0046] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 5.12-4.90 (m, 4H). 13C NMR (101 MHz, Chloroform-d) δ125.38-117.52, 96.37-91.45, 72.61. 19 F NMR (376 MHz, Chloroform-d) δ -74.41.

[0047] Example 7 - Synthesis and Preparation of Bis(2,2,3,3-Tetrafluoropropoxy)methane Tetrafluoropropanol (52 g, 394 mmol) was added to a 500 mL reaction flask, followed by dimethoxymethane (10 g, 131 mmol) at room temperature. The mixture was cooled to 5 °C, and polyphosphoric acid (2 g) was slowly added dropwise. The temperature was then raised to 60 °C and reacted for 4 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with ethyl acetate (150 mL), and allowed to stand to separate into layers. The lower layer of catalytic acid was removed, and the supernatant crude product was collected. The crude product was distilled under reduced pressure at 45 °C and 140 mbar to obtain 17 g of pure bis(2,2,3,3-tetrafluoropropoxy)methane, a colorless liquid, with a yield of 47%. GC chromatographic analysis showed a chemical purity of 99.5%; acidity was determined to be <1 ppm by titration; and chloride ion content was determined to be <1 ppm by ion chromatography.

[0048] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 6.40-5.93 (m, 2H), 4.66 (s, 2H), 4.03 (t, J=21.0Hz, 4H). 13 C NMR (101 MHz, Chloroform-d) δ 116.19, 109.86, 96.43, 62.23. 19 F NMR (376 MHz, Chloroform-d) δ -123.19, -138.94.

[0049] Example 8 - Synthesis and Preparation of bis[(2,2,3,3,4,4,5,5-octafluoropentyl)oxy]methane 2,2,3,3,4,4,5,5-octafluoro-1-pentanol (76.2 g, 329 mmol) was added to a 500 mL reaction flask, followed by dimethoxymethane (10 g, 131 mmol) at room temperature. The mixture was cooled to 5 °C, and polyphosphoric acid (3 g) was slowly added dropwise. The temperature was then raised to 80 °C and reacted for 4 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with ethyl acetate (150 mL), and allowed to stand to separate into layers. The lower layer of catalytic acid was removed, and the supernatant crude product was collected. The crude product was distilled under reduced pressure at 50 °C and 100 mbar to obtain 28 g of pure bis[(2,2,3,3,4,4,5,5-octafluoropentyl)oxy]methane, a colorless liquid with a yield of 45%. GC analysis showed a chemical purity of 99.6%; acidity was <1 ppm by titration; and chloride ion content was <1 ppm by ion chromatography.

[0050] The spectral data of the product are as follows: 1 H NMR (400 MHz, Chloroform-d) δ 6.01-6.34 (m, 2H), 4.67 (s, 2H), 4.03 (m, 4H). 13 C NMR (101 MHz, Chloroform-d) δ 117.23, 111.20, 111.08, 109.86, 95.91, 63.88. 19 F NMR (376 MHz, Chloroform-d) δ -121.03, -126.18, -137.84, -137.94.

[0051] Example 9 - Synthesis and Preparation of Bis(2,2,3,4,4,4-Hexafluorobutoxy)methane Hexafluorobutanol (59.8 g, 328 mmol) was added to a 500 mL reaction flask, followed by dimethoxymethane (10 g, 131 mmol) at room temperature. The mixture was cooled to 5 °C, and polyphosphoric acid (2.5 g) was slowly added dropwise. The temperature was then raised to 60 °C and reacted for 5 h. After the reaction was completed by GC monitoring, the mixture was cooled to room temperature, diluted with ethyl acetate (150 mL), and allowed to stand for phase separation. The lower catalytic acid layer was removed, and the supernatant crude product was collected. The crude product was distilled under reduced pressure at 40 °C and 150 mbar to obtain 22 g of pure bis(2,2,3,4,4,4-hexafluorobutoxy)methane, a colorless liquid, with a yield of 44%. GC analysis showed a chemical purity of 99.2%; acidity was determined to be <1 ppm by titration; and chloride ion content was determined to be <1 ppm by ion chromatography.

[0052] The spectral data of the product are as follows: 1H NMR (400 MHz, Chloroform-d) δ 4.68-4.88 (m, 2H), 4.68(s, 2H), 4.07(m, 4H). 13 C NMR (101 MHz, Chloroform-d) δ 120.36, 118.84, 96.42, 86.90, 65.02. 19 F NMR (376 MHz, Chloroform-d) δ -72.49, -111.12, -213.37.

[0053] The method for preparing fluorinated acetals disclosed in this application uses fluorinated alcohols and dimethoxymethane as raw materials to achieve efficient synthesis in the presence of an acid catalyst. The synthesis operation is simple and convenient, and the crude product can be separated into pure products by acid separation and distillation. Compared with the prior art, this method has higher production efficiency.

[0054] This application also provides an electrolyte for lithium-ion batteries. The electrolyte may include fluorinated acetal compounds as described above. The fluorinated acetal compounds possess fluorine-containing groups, and due to the high electronegativity of fluorine atoms, these groups can regulate the redox reaction at the electrode / electrolyte interface of the lithium-ion battery, promoting the formation of a CF-bonded SEI film. This film possesses both chemical stability and high lithium-ion conductivity. Furthermore, the high bond energy of the COC ether bonds in the molecule makes it resistant to high-voltage oxidation, making it particularly suitable for high-nickel cathodes. It is also less prone to hydrolysis, superior to traditional carbonates and ordinary acetals, reducing the generation of acidic byproducts from oxidative decomposition and hydrolysis of the electrolyte. Simultaneously, the hydrophobicity of fluorine atoms reduces the interaction between the electrolyte and water, inhibiting the generation of HF through electrolyte hydrolysis and preventing corrosion of the electrolyte material. Moreover, the electron-withdrawing effect of the fluorine-containing groups reduces the flammability of the acetal structure, improving battery safety without sacrificing ionic conductivity.

[0055] This application also provides a lithium-ion battery. The lithium-ion battery includes a cell, a package for encapsulating the cell, and an electrolyte injected into the package.

[0056] The battery cell includes a positive electrode, a negative electrode, and a separator. The separator is located between the positive and negative electrodes to prevent short circuits caused by contact between them. Simultaneously, it allows active lithium ions to pass through during charging and discharging. The separator can be a polymer film such as a polyethylene (PE) film, a polypropylene (PP) film, or a PP / PE / PP three-layer composite film. Alternatively, it can be obtained by functionally modifying the above polymer films. For example, a composite film consisting of a "polymer layer + polyolefin substrate" formed by coating a polyethylene film or a polypropylene film with polymers such as polyvinylidene fluoride (PVDF) or polymethyl methacrylate (PMMA).

[0057] The positive electrode includes a positive current collector and a positive active layer located on at least one side of the positive current collector. The positive current collector can be implemented using a metal plate with electronic conductivity. Currently known positive current collectors can all be used in this application. For example, the positive current collector is aluminum foil.

[0058] The positive electrode active layer may include a positive electrode active material, and at least one of a first binder and a first conductive agent. The positive electrode active material may be a material capable of intercalating or deintercalating metal ions such as lithium ions, including lithium-containing transition metal oxides, transition metal fluorides, polyanionic materials, fluorinated polyanionic materials, transition metal sulfides, transition metal fluorides, transition metal sulfides, or transition metal nitrides. Examples include LiCoO2, LiNiO2, LiMnO3, LiMn2O3, LiMnO2, Li2CuO2, and LiNiO2. x Mn2 x O4, LiNi x Co y Mn 1-x-y O2(NCM), LiNi 1-x-y Co x Al y O2(NCA), LiNi1 x M x O2 (M=Co, Mn, Al, Cu, Fe, Mg, B or Ga, x=0.01-0.3), LiMn1 x M x O2 (M = Co, Ni, Fe, Cr, Zn or Ta, x = 0.01-0.1), Li2Mn3MO8 (M = Fe, Co, Ni, Cu or Zn), etc., but not limited to these.

[0059] The first adhesive can be any known adhesive, including but not limited to polyvinylidene fluoride, polyvinylidene fluoride, polytetrafluoroethylene, polyethylene, polypropylene, aromatic polyamide resin, polyamide, polyimide, polyamide-imide, polyacrylonitrile, polyacrylic acid, polymethyl acrylate, polyethyl acrylate, polyhexyl acrylate, polymethacrylic acid, polymethyl methacrylate, polyethyl methacrylate, polyhexyl methacrylate, polyvinyl acetate, polyvinylpyrrolidone, polyether, polyethersulfone, polyhexafluoropropylene, styrene-butadiene rubber, carboxymethyl cellulose, etc., or any combination thereof, which can be used in this application. Copolymers can also be used as adhesives, exemplary of which are copolymers of two or more materials selected from tetrafluoroethylene, hexafluoroethylene, hexafluoropropylene, perfluoroalkyl vinyl ether, vinylidene fluoride, trifluorochloroethylene, ethylene, propylene, pentafluoropropylene, fluoromethyl vinyl ether, acrylic acid, hexadiene, etc. Alternatively, mixtures of two or more materials in the above examples can also be used as adhesives. In some implementations, the adhesive may include a fiberizable adhesive. For example, the adhesive may include, but is not limited to, polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), polyacrylic acid (PAA), styrene-butadiene rubber (SBR), carboxymethyl cellulose (CMC), polymethyl methacrylate (PMMA), polyacrylonitrile (PANO), polyvinyl alcohol (PVA), polyaniline (PANI), polypyrrole (PPy), seaweed nanofibers (CNF), sodium alginate (Alg), β-cyclodextrin polymer (β-CDp), polypropylene emulsion (LA132), etc., or any combination thereof, or functionalized derivatives of the above polymers or copolymers between monomers.

[0060] The first conductive agent may include, but is not limited to, carbon-based materials such as graphite (natural or artificial graphite), carbon black (acetylene black, Ketjen black, Super P, etc.), carbon nanotubes, graphene, etc.; metal-based materials such as metal powders (aluminum powder, nickel powder, etc.), metal oxides (titanium oxide, etc.), metal whiskers (alumina, oxidizing agents, etc.); conductive polymers such as polyaniline, polypyrrole, polythiophene, etc.; conductive fibers such as carbon fibers, metal fibers, metal compound fibers, polymer fibers, etc.; or other known conductive agents.

[0061] The positive electrode active layer may further include a solid electrolyte, which may be an inorganic solid electrolyte or a polymer solid electrolyte. The inorganic solid electrolyte may include, but is not limited to, halide solid electrolytes, sulfide solid electrolytes, oxide solid electrolyte materials, nitride solid electrolytes, hydride solid electrolytes, borate solid electrolytes, etc.

[0062] Suitable, but not limited, halide solid electrolytes may include, but are not limited to, LaF3, LiCl, LiI, etc., or those with the chemical formula Li a MX bThis refers to lithium halide solid electrolytes, where M represents a metallic or metalloid element, including one or more of B, Si, Ge, As, Sb, Te, Al, Zn, Mg, Ca, Ba, Mn, Cd, Co, Yb, Y, Cr, In, Ga, Sr, Hf, Ti, Ta, Sn, Nb, Er, Sc, etc., and X represents a halogen element such as F, Cl, Br, I, etc. Examples include Li₂CdCl₄, Li₂MgCl₄, Li₂CdI₄, Li₂ZnI₄, Li₂ZrCl₆, Li₃YCl₆, and derivatives produced by doping or coating Li₃InCl₆ or related materials.

[0063] Suitable, but not limiting, sulfide solid electrolytes may include, but are not limited to, Li2S. P2S5, Li2S P2S5–MS x (M=Si, Ge, Sn, 0≤x≤2), Li 9.6 P3S 12 Li7P3S 11 Li7P2S8I, Li 10 SnP2S 12 Li 10 SiP2S 12 Li9P3S9O3, LGPS(Li 10 GeP2S 12 Thio-LISICON (Li 3.25 Ge 0.25 P 0.75 S4), Li6PS5X (X=Cl, Br, I), Li3PS4-X (X=Cl, Br, I), Li4SnS4-X (X=Cl, Br), Li 3.25 Ge 0.25 P 0.75 S4, Li 3.4 Si 0.4 P 0.6 S4, Li 10 GeP2S 11.7 O 0.3 Li 9.54 Si 1.74 P 1.44 S 11.7 Cl 0.3 Li 10.35 Ge 1.35 P 1.65 S 12 Li 10.35 Si 1.35 P 1.65 S 12 Li 9.81 Sn0.81 P 2.19 S 12 Li 10 (Si 0.5 Ge 0.5 P2S 12 Li 10 (Ge 0.5 Sn 0.5 P2S 12 Li 10 (Si 0.5 Sn 0.5 P2S 12 Li6 (PS5) 0.7 (GeS4) 0.3 Cl、Li 7.5 P 2.5 Sn 0.5 S 10.5 Cl 1.5 Li6PS5Cl 0.5 Br 0.5 Li6PS5I 0.2 Cl 0.8 Li5SnS2C l3 Li 10 P3S 12 Cl2, Li7P2S 8.5 Cl 0.5 Derivatives produced by doping or coating with materials such as or any combination thereof or related materials.

[0064] Suitable, but not limited, oxide solid electrolytes may include, but are not limited to, NASICON-type solid electrolytes such as LiTi2(PO4)3, LiGeTi(PO4)3, LiGe2(PO4)3, LiHf2(PO4)3, and Li 1+x Al x Ge2 x (PO4)3(LAGP, where 0 ≤ x ≤ 2), Li 1+x Al x Ti2 x (PO4)3(LATP, where 0 ≤ x ≤ 2), Li 1+x Y x Zr2 x (PO4)3(LYZP, where 0≤x≤2), Li 1.3 Al 0.3 Ti 1.7 (PO4)3, etc., perovskite-type solid electrolytes such as Li 3x La( 2 / 3 x )TiO3 (LLTO, where 0 < x < 0.25), LiSr 1.65 Zr 1.3 Ta 1.7 O9, Li 2x y Sr1 x Ta y Zr1 y O3 (where x = 0.75y and 0.60 < y < 0.75), etc., LISICON-type solid electrolytes such as Li 14 ZnGe4O 16 、Li4SiO4, LiGeO4, etc., garnet-type solid electrolytes such as Li7La3Zr2O 12 、Li 6.5 La3Zr 1.75 Te 0.25 O 12 、Li 6.2 Ga 0.3 La 2.95 Rb 0.05 Zr2O 12 、Li 6.85 La 2.9 Ca 0.1 Zr 1.75 Nb 0.25 O 12 、Li 6.25 Al 0.25 La3Zr2O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 、Li 6.75 La3Zr 1.75 Nb 0.25 O 12 etc., or derivatives produced by doping or coating improvement with any combination or related materials thereof.

[0065] Some suitable but non-limiting nitride solid electrolytes can include, but are not limited to, Li3N, Li7PN4, LiSi2N3, Li9N2Cl3, etc. Some suitable but non-limiting hydride solid electrolytes can include, but are not limited to, LiBH4, LiBH4 - Li X(X = Cl, Br, or I), LiNH2, Li2NH, LiBH4-LiNH2, Li3AlH6, etc. Some suitable but not limited borate solid electrolytes may include, but are not limited to, Li2B4O7, Li2O-B2O3-P2O5, Li2B... 10 H 10 -Li2B 12 H 12 Examples include Li7N2I-0.5LiOH. Derivatives of these electrolytes obtained through substitution, doping, modification, and compositing can also serve as the inorganic solid electrolytes described in this application. For instance, bromine-substituted or partially substituted Li2ZrCl6, such as Li2ZrCl... 6-x Br x Rare earth metals such as lanthanum or yttrium-doped Li6PS5Br, and LLZO deposited on indium (In) surfaces, etc. It should be noted that the above examples are for illustrative purposes only and are not intended to limit the scope of this application.

[0066] Polymer solid electrolytes can be composed of polymers and lithium salts. Suitable, but not limiting, polymers that participate in the formation of polymer solid electrolytes may include, but are not limited to, polyether polymers, polycarbonate polymers, polyamide polymers, polyacrylate polymers, polysiloxane polymers, polyphosphazene polymers, polyolefin polymers, polyepoxide polymers, polyphosphate polymers, polyimide polymers, polyurethane polymers, and any combination thereof. For example, homopolymers such as polyethylene oxide (PEO) or copolymers (e.g., PEG-PPG block copolymers or PVDF-HFP) can participate in the formation of the polymer electrolyte. The lithium salts may include, but are not limited to, lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), lithium bis(fluorosulfonyl)imide (LiFSI), lithium trifluoromethanesulfonate (LiOTF), lithium hexafluorophosphate (LiPF6), lithium hexafluoroborate (LiBF6), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium difluorophosphate (LiPO2F2), lithium hexafluoroarsenate, and tris(pentafluoroethyl)... Lithium trifluorophosphate, lithium perchlorate, lithium tetrafluoroborate, cyclodifluoromethane 1,1 Lithium bis(sulfonyl)imide, cyclodifluoromethane 1,1 Lithium bis(sulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide, lithium bis(fluoromalonic acid)borate, lithium tetracyanoborate, lithium dicyanotriazole salt, dicyano Trifluoromethyl Imidazole lithium salt, dicyano Pentafluoroethyl) Imidazole lithium salt or others.

[0067] The negative electrode sheet may include a negative electrode current collector and a negative electrode active layer located on at least one side of the negative electrode current collector. The negative electrode current collector can be implemented using a metal plate with electronic conductivity. Currently known negative electrode current collectors can all be used in this application. For example, the negative electrode current collector is copper foil.

[0068] The negative electrode active layer can be made using a corresponding negative electrode active material. Exemplary negative electrode active materials can be metallic materials (such as Li, Ag, Al, Bi, Cu, Ga, Ge, In, Ni, Pb, Sb, Si, Sn, Sr, Zn, etc., or alloys or compounds of the above metals, such as Li–Sn alloys, Li–Sn–O alloys, Sn, SnO, SnO2, TiO2–Li4Ti5O) 12 Li-Al alloys, Ag-C alloys, etc.), carbon materials (such as graphite including natural / artificial graphite, carbon fiber, soft carbon, hard carbon, crystalline carbon, amorphous carbon, etc.), silicon compounds (such as silicon, silicon-carbon composites), etc., or composite materials formed by metals and carbon / silicon, such as Li-C composite anode sheets.

[0069] The second adhesive may be the same as or similar to the first adhesive, and the second conductive agent may be the same as or similar to the first conductive agent. Please refer to the foregoing descriptions for details.

[0070] The battery cell can be a wound battery cell, formed by sequentially stacking and winding the positive electrode, the separator, and the negative electrode. The battery cell can also be a laminated battery cell, comprising multiple stacked positive and negative electrode plates, which are alternately placed and separated by the separator.

[0071] The encapsulation body may include, but is not limited to, flexible packaging materials, such as aluminum-plastic film. The encapsulation body may also be other suitable materials, and this application is not limited thereto.

[0072] The electrolyte may include an organic solvent, an electrolyte salt, and additives. The organic solvent may be one of the fluorinated acetal compounds described above. Alternatively, the organic solvent may be a mixture of the fluorinated acetal compound and one or more of ethylene carbonate (EC), propylene carbonate (PC), ethyl methyl carbonate (EMC), diethyl carbonate (DEC), dimethyl carbonate (DMC), dipropyl carbonate (DPC), methyl propyl carbonate (MPC), or ethyl propyl carbonate (EPC). The electrolyte salt may include a lithium salt, which may include, but is not limited to, lithium trifluoromethanesulfonylimide (LiTFSI), lithium bisfluorosulfonylimide (LiFSI), lithium trifluoromethanesulfonate (LiOTF), lithium hexafluorophosphate (LiPF6), lithium hexafluoroborate (LiBF6), lithium difluorooxalate borate (LiDFOB), lithium bis(oxalate borate) (LiBOB), lithium difluorophosphate (LiPO2F2), and hexafluoroarsenic acid. The additive may be one or more of the following: lithium, lithium tris(pentafluoroethyl)-trifluorophosphate, lithium perchlorate, lithium tetrafluoroborate, lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide, lithium cyclodifluoromethane-1,1-bis(sulfonyl)imide, lithium bis(perfluoroethanesulfonyl)imide, lithium bis(fluoromalonic acid)borate, lithium tetracyanoborate, lithium dicyanotriazole, lithium dicyano-trifluoromethyl-imidazolium, and lithium dicyano-pentafluoroethyl)-imidazolium. The additive may include, but is not limited to, one or more of vinylene carbonate (VC), ethylene ethylene carbonate (VEC), fluoroethylene carbonate (FEC), succinic anionyl (SN), and adiponitrile (AND).

[0073] The lithium-ion battery can be manufactured by assembling the positive electrode, the separator, and the negative electrode into a cell, then encapsulating the cell in a package, and performing processes such as electrolyte injection, settling, formation, aging, and shaping. Alternatively, other manufacturing processes in the art can be applied here, and no particular limitation is made.

[0074] This application also discloses a battery module comprising multiple lithium-ion batteries as described above, which are electrically connected and arranged together. This battery module can be applied to electrically driven vehicles, including but not limited to electric vehicles, hybrid vehicles, and energy storage devices such as energy storage systems.

[0075] The fluorinated acetal compounds provided in this application can facilitate industrial production, further promote the industrial development of fluorinated acetal-based next-generation electrolyte solvents, and meet the growing needs of high-performance battery technology.

[0076] This application has described the basic concepts. Obviously, for those skilled in the art, the above detailed disclosure is merely illustrative and does not constitute a limitation of this application. Although not explicitly stated herein, those skilled in the art may make various modifications, improvements, and corrections to this application. Such modifications, improvements, and corrections are suggested in this application, and therefore such modifications, improvements, and corrections still fall within the spirit and scope of the exemplary embodiments of this application.

[0077] Furthermore, this application uses specific terms to describe its embodiments. For example, "an embodiment," "one embodiment," and / or "some embodiments" refer to a particular feature, structure, or characteristic related to at least one embodiment of this application. Therefore, it should be emphasized and noted that "an embodiment," "one embodiment," or "an alternative embodiment" mentioned twice or more in different locations in this application do not necessarily refer to the same embodiment. In addition, certain features, structures, or characteristics in one or more embodiments of this application can be appropriately combined.

[0078] Similarly, it should be noted that, in order to simplify the description of this application and thus aid in the understanding of one or more embodiments of the invention, the foregoing description of the embodiments of this application sometimes combines multiple features into one embodiment or its description. However, this disclosure method does not imply that the subject matter of this application requires more features than those mentioned in the claims. In fact, the embodiments have fewer features than all the features of the single embodiments disclosed above.

[0079] Finally, it should be understood that the embodiments described in this application are merely illustrative of the principles of the embodiments of this application. Other modifications may also fall within the scope of this application. Therefore, alternative configurations of the embodiments of this application are considered as examples and not limitations, and are regarded as consistent with the teachings of this application. Accordingly, the embodiments of this application are not limited to the embodiments explicitly described and illustrated in this application.

Claims

1. A method for preparing a fluorinated acetal compound, characterized in that, The preparation method includes the following steps: The crude product was obtained by reacting fluoroalcohols with dimethoxymethane using acid catalysis. The crude product of the reaction was purified to obtain the fluorinated acetal compound; wherein, The structural formula of the fluorinated acetal compound is shown in Formula I): Formula I); Among them, R f Selected from fluoroalkyl groups with C1 to C6 carbon atoms.

2. The preparation method according to claim 1, characterized in that, The acid includes at least one of p-toluenesulfonic acid, trifluoroacetic acid, acetic acid, formic acid, concentrated sulfuric acid, or polyphosphoric acid.

3. The preparation method according to claim 1, characterized in that, The molar ratio of the fluoroalcohol to the dimethoxymethane is (2-5):

1.

4. The preparation method according to claim 1, characterized in that, The mass ratio of the acid to the fluorinated alcohol compound is (0.01-0.1):

1.

5. The preparation method according to claim 1, characterized in that, The reaction of the fluoro alcohol compound with dimethoxymethane satisfies at least one of the following conditions: (1) The reaction temperature is 30℃-80℃; (2) The reaction time is 1h~16h.

6. The preparation method according to claim 1, characterized in that, The purification operation includes separation and acid removal: using an organic solvent to remove the acid by extraction and layering; wherein the density of the organic solvent is less than 1 g / mL.

7. The preparation method according to claim 6, characterized in that, The organic solvent is selected from at least one of petroleum ether, n-hexane, or ethyl acetate.

8. The preparation method according to claim 6, characterized in that, The purification operation further includes distillation purification, wherein the distillation purification satisfies at least one of the following conditions: (1) The distillation temperature is 20℃-90℃; (2) The distillation pressure is 1 mbar to 200 mbar.

9. The preparation method according to any one of claims 1-8, characterized in that, R f The number of substituted fluorine atoms on each carbon atom is 0-3.

10. The preparation method according to any one of claims 1-8, characterized in that, The fluorinated acetals include one or more of the following compounds: 、 、 、 、 、 、 。

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