Preparation method of trifluoromethyl sulfinate

Abstract

The embodiment of the invention discloses a preparation method of trifluoromethyl sulfinate. The preparation method comprises the following steps: reacting a trifluoromethyl sulfinyl reagent with an amino compound containing hydroxyl to obtain a trifluoromethyl sulfinate intermediate; and reacting the trifluoromethyl sulfinate intermediate with alkali metal salt in an organic solvent to obtain the trifluoromethyl sulfinate. According to the embodiment of the invention, firstly, the trifluoromethyl sulfinyl reagent reacts with the amino compound containing the hydroxyl group to obtain the trifluoromethyl sulfinate intermediate, and then the trifluoromethyl sulfinate and the alkali metal salt react in the organic solvent, so that the high-purity trifluoromethyl sulfinate can be prepared with high yield under mild conditions. The yield and the purity of the target product are effectively improved, and meanwhile, the production condition requirement and the environmental pollution degree are reduced, so that large-scale production and application are facilitated.

Description

Technical Field

[0001] This application relates to the field of lithium battery electrolyte technology, and in particular to a method for preparing trifluoromethyl sulfinate. Background Technology

[0002] Non-aqueous electrolyte secondary batteries, such as lithium-ion batteries, are being used in various fields. In recent years, the market's performance requirements for non-aqueous electrolyte secondary batteries have been increasing. When lithium-ion batteries are used as power sources for electric vehicles, the large energy required for starting and acceleration, and the need to effectively regenerate the high energy generated during deceleration, leads to lithium-ion consumption in the battery. Therefore, the lithium in the degraded lithium battery needs to be effectively replenished. Lithium trifluoromethyl sulfinate, as a high-quality non-aqueous electrolyte for lithium-ion secondary batteries, can effectively solve the above problems. Lithium trifluoromethyl sulfinate can precisely replenish lost lithium ions, achieve capacity recovery, and thus significantly extend battery life. It also has good compatibility with various battery active materials and electrolytes, resulting in high market demand.

[0003] In the prior art, the preparation methods of trifluoromethyl sulfinate mainly include the following four types: (1) the method described in the New Journal of Chemistry 2024, 48, 17097, which describes the reaction of trifluoromethyl sulfonyl chloride / fluorine under the conditions of sodium carbonate, sodium sulfite, ethanol and water to obtain trifluoromethyl sulfinate; (2) the method reported in the Eur. J. Org. Chem. 2009, 1390, which describes the reaction of trifluoromethyltrimethylsilane, potassium fluoride and sulfur dioxide to generate potassium trifluoromethyl sulfinate; (3) the method reported in the Science of Synthesis 2005, 18, 1135, which describes the reaction of potassium trifluoromethylformate and sulfur dioxide to prepare potassium trifluoromethyl sulfinate; (4) the method described in the Journal of Fluorine Chemistry In 2007, 128, 1187, a method for producing sodium trifluoromethyl sulfinate by reacting trifluorobromomethane, DMF, water, sodium dihydrogen phosphate, and sodium dithionite was reported. However, these methods have low yields and generate a large amount of waste. In particular, methods (2) and (3) use highly toxic sulfur dioxide, which pollutes the environment and is not suitable for industrial application.

[0004] Therefore, how to provide a method for preparing trifluoromethyl sulfinate that can improve the yield and purity of the target product while reducing the requirements for production conditions, thus facilitating large-scale production and application, has become an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0005] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a method for preparing trifluoromethyl sulfinate, to solve the problems of low yield, heavy pollution, and unsuitability for large-scale industrial production of trifluoromethyl sulfinate in current preparation methods.

[0006] Specifically, this application provides a method for preparing trifluoromethyl sulfinate, comprising: Trifluoromethyl sulfinyl reagent was reacted with an amino compound containing a hydroxyl group to obtain a trifluoromethyl sulfinyl ester intermediate; The trifluoromethyl sulfinate intermediate is reacted with an alkali metal salt in an organic solvent to obtain the trifluoromethyl sulfinate.

[0007] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the structural formula of the trifluoromethyl sulfinate intermediate is as follows: ; Wherein, R is selected from any one of butyrylimide, maleimide, o-phenylbutyrylimide, and pyrazolide.

[0008] In one embodiment of the above-described method for preparing trifluoromethyl sulfinic acid salt, the reaction of the trifluoromethyl sulfinic acid reagent with an amino compound containing a hydroxyl group is carried out in a solvent selected from one or more of ethanol, methanol, propanol, dichloromethane, chloroform, 1,2-dichloroethane, tetrachloroethane, and chlorobenzene.

[0009] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the step of reacting a trifluoromethyl sulfinyl reagent with an amino compound containing a hydroxyl group to obtain the trifluoromethyl sulfinate intermediate includes: An alcohol-base is formed by reacting an amino compound containing a hydroxyl group with an inorganic base. The trifluoromethyl sulfinyl ester intermediate is obtained by reacting the alcohol base with a trifluoromethyl sulfinyl reagent.

[0010] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the trifluoromethyl sulfinyl reagent is selected from trifluoromethyl sulfinyl chloride and / or trifluoromethyl sulfinyl fluoride; and / or, The hydroxyl-containing amino compound is selected from the structure of [structure not specified]. N-hydroxysuccinimide (NHS), with the structural formula as follows: N-hydroxyphthalimide, with the structural formula: N-hydroxymaleimide, with the structural formula: One or more of 1-hydroxypyrazoles.

[0011] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the alkali metal salt is selected from at least one of alkali metal halide, alkali metal carbonate, alkali metal bicarbonate, alkali metal oxide, alkali metal hydroxide, or alkali metal alkali alcohol. The cation in the alkali metal salt is selected from at least one of lithium ions, sodium ions, or potassium ions.

[0012] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the molar ratio of the cation in the alkali metal salt to the trifluoromethyl sulfinate intermediate is 1:1 to 4:1.

[0013] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the organic solvent is selected from aprotic solvents; The aprotic solvent is selected from at least one of the following: chain carbonates, cyclic carbonates, chain carboxylic esters, chain ethers, or cyclic ether solvents.

[0014] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the mass ratio of the organic solvent to the trifluoromethyl sulfinate intermediate is 3:1 to 8:1.

[0015] In one embodiment of the above-described method for preparing trifluoromethyl sulfinate, the step of reacting the trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent to obtain trifluoromethyl sulfinate comprises: The reaction solution containing trifluoromethyl sulfinate was obtained by reacting the trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent. After concentrating the reaction solution, a poor solvent is added to obtain trifluoromethyl sulfinate solid; The undesirable solvent is selected from halogenated hydrocarbon solvents.

[0016] The above-described one or more embodiments of this application have at least one or more of the following beneficial effects: This application provides a method for preparing trifluoromethyl sulfinate. First, a trifluoromethyl sulfinyl reagent is reacted with an amino compound containing a hydroxyl group to obtain a trifluoromethyl sulfinate intermediate. Then, the trifluoromethyl sulfinate and an alkali metal salt are reacted in an organic solvent. This method can produce high-purity trifluoromethyl sulfinate in high yield under mild conditions, effectively improving the yield and purity of the target product, while reducing the requirements for production conditions and the degree of environmental pollution, thus facilitating large-scale production and application.

[0017] Additional aspects and advantages of this application 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 this application. Detailed Implementation

[0018] Some embodiments of this application are described below. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of this application and are not intended to limit the scope of protection of this application.

[0019] As described in the background section, when lithium-ion batteries are used as power sources for electric vehicles, the lithium ions in the batteries are consumed and need to be effectively replenished. Using trifluoromethyl sulfinate as a non-aqueous electrolyte for lithium-ion batteries can effectively solve this problem. Currently, the yield of trifluoromethyl sulfinate preparation methods is low. In particular, the preparation method using a mixture of trifluoromethyltrimethylsilane, potassium fluoride, and sulfur dioxide, and the preparation method using trifluorobromomethane, DMF, water, sodium dihydrogen phosphate, and sodium dithionite to produce trifluoromethyl sulfinate use highly toxic sulfur dioxide, causing serious environmental pollution and making it unsuitable for large-scale industrial production.

[0020] To address the aforementioned issues, this application creatively proposes a method for preparing trifluoromethyl sulfinate. First, a trifluoromethyl sulfinyl reagent is reacted with an amino compound containing a hydroxyl group to obtain a trifluoromethyl sulfinate intermediate. Then, by reacting the trifluoromethyl sulfinate with an alkali metal salt in an organic solvent, high-purity trifluoromethyl sulfinate can be produced in high yield under mild conditions. This effectively improves the yield and purity of the target product while reducing production requirements and environmental pollution, thus facilitating large-scale production and application.

[0021] The present application will be described in detail below through specific embodiments.

[0022] Specifically, this application provides a method for preparing trifluoromethyl sulfinate, comprising: S1. Trifluoromethyl sulfinyl reagent is reacted with an amino compound containing a hydroxyl group to obtain a trifluoromethyl sulfinyl ester intermediate.

[0023] S2. Trifluoromethyl sulfinate is obtained by reacting a trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent.

[0024] The method for preparing trifluoromethyl sulfinate provided in this application, by reacting trifluoromethyl sulfinate and alkali metal salt in an organic solvent, can produce high-purity trifluoromethyl sulfinate in high yield under mild conditions. Furthermore, the preparation method simplifies the operation process, reduces the generation of by-products, improves the yield and purity of the target product, and lowers the requirements for production conditions, thus facilitating large-scale production applications.

[0025] Compared to the method of generating sodium trifluoromethylsulfonyl chloride by heating and refluxing in sodium carbonate, sodium sulfite, ethanol and water, this application does not generate a large amount of wastewater and solid waste, and the reaction can be carried out at room temperature, which reduces the environmental pollution of the production process and reduces the energy consumption requirements of the production process.

[0026] Compared to the method of reacting trifluoromethyltrimethylsilane, potassium fluoride and sulfur dioxide, this application avoids the environmental pollution caused by the use of toxic sulfur dioxide raw materials, and has high requirements for equipment materials.

[0027] Compared to the method of producing sodium trifluoromethyl sulfinate by reacting trifluorobromomethane, DMF, water, sodium dihydrogen phosphate, and sodium dithionite, this application achieves a high-yield, high-purity sodium trifluoromethyl sulfinate under mild conditions through simple and conventional operations, eliminating the need for cumbersome purification steps and facilitating industrial production. The term "amine group" refers to a compound formed when the hydrogen atom in an ammonia molecule (NH3) is replaced by a hydrocarbon group. The amine group can be a primary amine (two hydrogen atoms and one hydrocarbon group attached to a nitrogen atom), a secondary amine (one hydrogen atom and two hydrocarbon groups attached to a nitrogen atom), or a tertiary amine (no hydrogen atom attached to a nitrogen atom, only three hydrocarbon groups attached). The term "hydrocarbon group" refers to a group containing only carbon and hydrogen atoms. The hydrocarbon group can be straight-chain, branched, or cyclic, and the number of carbon atoms can be, for example, C1–C5, C1–C4, C1–C3, C1–C2, etc. For example, hydrocarbon groups include, but are not limited to, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, etc.

[0028] Trifluoromethylsulfinyl reagents can be trifluoromethylsulfinyl fluoride, with the following structural formula: ; Trifluoromethylsulfinyl reagents can also be trifluoromethylsulfinyl chlorides, with the following structural formula: .

[0029] Amine compounds containing hydroxyl groups can have the following structural formula: N-hydroxysuccinimide (NHS), with the structural formula as follows: N-hydroxyphthalimide, with the structural formula: N-hydroxymaleimide, with the structural formula: One or more of 1-hydroxypyrazoles.

[0030] In some embodiments of this application, the structural formula of trifluoromethyl sulfinate is: ; R is selected from heterocyclic amines.

[0031] Preferably, R is selected from any one of butyrylimide, maleimide, o-phenylbutyrylimide, or pyrazolyl, and the trifluoromethylsulfinyl group (CF3SO2) in the trifluoromethylsulfinyl ester intermediate is... - It is linked to an amino compound containing a hydroxyl group via an ester bond.

[0032] By quasi-designing the R group to be selected from heterocyclic amine groups such as butyrylimide, maleimide, o-phenylbutyrylimide, or pyrazolide, the obtained trifluoromethyl sulfinates can introduce functional amine skeletons while retaining the characteristics of the CF3 group, providing a variety of intermediate options.

[0033] Considering the ease of subsequent product purification, the purity of the trifluoromethyl sulfinate intermediate is greater than 99%.

[0034] For example, N-hydroxysuccinimide is reacted with a trifluoromethyl sulfinyl reagent to generate trifluoromethyl sulfinyl succinimide ester containing a butyrylimide group; N-hydroxyphthalimide is reacted with a trifluoromethyl sulfinyl reagent to generate trifluoromethyl sulfinyl phthalimide ester containing an ortho-butyrylimide group; N-hydroxymaleimide is reacted with a trifluoromethyl sulfinyl reagent to generate trifluoromethyl sulfinyl maleimide ester containing a heterocyclic amine group; and 1-hydroxypyrazole is reacted with a trifluoromethyl sulfinyl reagent to generate trifluoromethyl sulfinyl pyrazole ester containing a pyrazole group.

[0035] In some embodiments of this application, the reaction between the trifluoromethyl sulfinyl reagent in S1 and the hydroxyl-containing amino compound is carried out in a solvent selected from one or more of ethanol, methanol, propanol, dichloromethane, chloroform, 1,2-dichloroethane, tetrachloroethane, and chlorobenzene.

[0036] In some embodiments, the reaction of a trifluoromethyl sulfinyl reagent with an amino compound containing a hydroxyl group to obtain a trifluoromethyl sulfinyl ester intermediate includes: An alcohol-base is formed by reacting an amino compound containing a hydroxyl group with an inorganic base. The trifluoromethyl sulfinyl ester intermediate is obtained by reacting the alcohol base with a trifluoromethyl sulfinyl reagent.

[0037] The term "inorganic base" refers to alkaline compounds that do not contain carbon, such as sodium hydroxide, potassium hydroxide, potassium carbonate, cesium carbonate, sodium carbonate, etc.

[0038] Specifically, amine compounds containing hydroxyl groups react with inorganic bases to generate alkoxide anions (ROA). - Then, the alkoxide anion reacts with the trifluoromethyl sulfinyl reagent to generate trifluoromethyl sulfinyl ester CF3SO2-R.

[0039] For example, in N-hydroxyphthalimide (NHPI), the N atom is attached to a hydroxyl group, which can be deprotonated by an inorganic base to generate the corresponding alcohol base, with the alcohol base structure being NHPI-O. - The alcohol base acts as a nucleophile to attack the S atom in the trifluoromethyl sulfinyl reagent, generating the trifluoromethyl sulfinyl ester intermediate NHPI-O-SO2-CF3.

[0040] Preferably, the molar amount of the inorganic base is greater than the molar amount of the amine compound containing the hydroxyl group. The excess of the inorganic base ensures complete deprotonation of the hydroxyl group and can neutralize the byproduct acid.

[0041] In some embodiments of this application, the trifluoromethylsulfinyl reagent is selected from trifluoromethylsulfinyl chloride and / or trifluoromethylsulfinyl fluoride.

[0042] In some embodiments of this application, the alkali metal salt is selected from at least one of alkali metal halide, alkali metal carbonate, alkali metal bicarbonate, oxides of alkali metals, hydroxides of alkali metals, or alcohols of alkali metals. The cation in the alkali metal salt is selected from at least one of lithium ions, sodium ions, or potassium ions.

[0043] Among them, alkali metal halide salts include, but are not limited to, one or more of lithium fluoride, lithium chloride, lithium bromide, sodium fluoride, sodium chloride, sodium bromide, potassium fluoride, potassium chloride, and potassium bromide; alkali metal carbonate salts include, but are not limited to, one or more of lithium carbonate, sodium carbonate, and potassium carbonate; alkali metal bicarbonate salts include, but are not limited to, one or more of lithium bicarbonate, sodium bicarbonate, and potassium bicarbonate; alkali metal oxides include, but are not limited to, one or more of lithium oxide, sodium oxide, and potassium oxide; alkali metal hydroxides include, but are not limited to, one or more of lithium hydroxide, sodium hydroxide, and potassium hydroxide; and alkali metal alcohols include, but are not limited to, one or more of sodium methoxide, sodium ethoxide, lithium methoxide, lithium ethoxide, potassium methoxide, potassium ethoxide, and potassium tert-butoxide.

[0044] From the perspective of ease of reaction and easier acquisition of high-purity products, alkali metal carbonates, alkali metal bicarbonates, oxides of alkali metals, hydroxides of alkali metals, or alkali metal alcohols are preferred. The alkali metal salts used in the reactions of this application can be commercially available products, purified products, or products manufactured from other compounds. There are no particular limitations on their purity, but alkali metal salts with a purity of 99% or higher are preferred.

[0045] In some embodiments of this application, the molar ratio of the cation in the alkali metal salt to the trifluoromethyl sulfinate intermediate is 1:1 to 4:1. Optionally, the molar ratio of the cation in the alkali metal to the trifluoromethyl sulfinate intermediate can be 1:1, 1.2:1, 1.5:1, 1.8:1, 2:1, 2.1:1, 2.5:1, 2.9:1, 3:1, 3.3:1, 3.5:1, 3.7:1, 4:1, or any value within the above range. For example, the molar ratio of the cation in the alkali metal to the trifluoromethyl sulfinate intermediate is 1.05:1, which ensures reaction yield while reducing raw material costs.

[0046] In the reaction process of this invention, when the feed amount of trifluoromethyl sulfinate is excessive relative to the cation in the alkali metal salt, it may cause some acidic substances to remain in the obtained trifluoromethyl sulfinate, thus posing a potential risk of deterioration in the quality and performance of the obtained trifluoromethyl sulfinate. Therefore, the lower limit of the feed molar ratio of the cation in the alkali metal salt to trifluoromethyl sulfinate is preferably 2 times or more, more preferably 2.05 times or more, and the upper limit is preferably 4 times or less, more preferably 3 times or less, and even more preferably 2.4 times or less. When the feed molar ratio of the cation in the alkali metal salt to trifluoromethyl sulfinate is adjusted to the above range, high-purity trifluoromethyl sulfinate can be produced in high yield without a cumbersome purification process.

[0047] In some embodiments of this application, the organic solvent is selected from aprotic solvents, which are solvents that do not provide hydrogen ions during the dissolution process.

[0048] The aprotic solvent is selected from at least one of linear carbonates, cyclic carbonates, linear carboxylic esters, linear ethers, or cyclic ether solvents. For example, linear carbonates may be dimethyl carbonate, ethyl methyl carbonate, diethyl carbonate, etc.; cyclic carbonates may be ethylene carbonate, propylene carbonate, vinylene carbonate, etc.; and linear carboxylic esters may be ethyl acetate, methyl acetate, isopropyl acetate, etc. Preferably, the organic solvent is selected from at least one of dimethyl carbonate, diethyl carbonate, ethyl acetate, n-butyl acetate, and ethylene glycol dimethyl ether.

[0049] In some embodiments of this application, the mass ratio of the organic solvent to the trifluoromethyl sulfinate intermediate is 3:1 to 8:1. Optionally, the mass ratio of the organic solvent to the trifluoromethyl sulfinate intermediate can be 3:1, 3.3:1, 4:1, 4.5:1, 5:1, 5.4:1, 6:1, 6.2:1, 7:1, 7.7:1, 8:1, or any ratio within the above range.

[0050] The organic solvent used in this application is preferably used in a mass ratio of 20 times or less to trifluoromethyl sulfinate, more preferably 15 times or less, and even more preferably 10 times or less. In addition, the organic solvent used in the reaction is preferably used in a mass ratio of 3 times or more to trifluoromethyl sulfinate, more preferably 2 times or more. Within the above range, the preparation efficiency is excellent, and trifluoromethyl sulfinate will not precipitate excessively, causing unnecessary yield loss.

[0051] To effectively remove organic solvent residues, organic solvents with a boiling point below 200°C are selected, more preferably organic solvents with a boiling point below 150°C at atmospheric pressure, and even more preferably organic solvents with a boiling point below 100°C at atmospheric pressure.

[0052] In some embodiments of this application, the step of reacting the trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent to obtain trifluoromethyl sulfinate comprises: The reaction solution containing trifluoromethyl sulfinate was obtained by reacting the trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent.

[0053] After concentrating the reaction solution, a poor solvent is added to obtain trifluoromethyl sulfinate solid; The undesirable solvent is selected from halogenated hydrocarbon solvents.

[0054] Specifically, after the reaction of the trifluoromethyl sulfinate intermediate with the alkali metal salt in an organic solvent is completed, the resulting reaction solution is concentrated, a poor solvent is added, crystallization is performed, and the solution is filtered to obtain a filter cake. The filter cake is then dried to obtain trifluoromethyl sulfinate solid.

[0055] Halogenated hydrocarbon solvents include, but are not limited to, at least one of dichloromethane, dichloroethane, tetrachloroethane, and chloroform.

[0056] Preferably, the halogenated hydrocarbon is selected from at least one of dichloromethane, dichloroethane, and tetrachloroethane.

[0057] This application does not specifically limit the reaction temperature of the trifluoromethyl sulfinate intermediate and the alkali metal salt in an organic solvent, but preferably below 60°C, more preferably below 50°C, and even more preferably below 45°C. Furthermore, the reaction temperature is preferably above 35°C, more preferably above 30°C, and even more preferably above 25°C. When the initial reaction temperature of the trifluoromethyl sulfinate intermediate and the alkali metal salt in the organic solvent is within the above-mentioned range, unpredictable side reactions are less likely to occur, and the reaction rate will not be too low.

[0058] This application does not have any particular limitation on the order in which the trifluoromethyl sulfinate intermediate and the alkali metal salt are added to the reaction system in an organic solvent. The solid alkali metal salt can be added to the stirred trifluoromethyl sulfinic acid solution, or the mixture of trifluoromethyl sulfinic acid and solvent can be added dropwise to the stirred mixture of alkali metal salt and non-aqueous organic solvent.

[0059] This application does not have a particular limitation on the feed time for the reaction of the trifluoromethyl sulfinate intermediate and the alkali metal salt in an organic solvent, but it is preferably 10 hours or less, more preferably 8 hours or less, and even more preferably 6 hours or less. Furthermore, the feed time in the reaction step of this application is preferably 30 minutes or more, more preferably 2 hours or more, and even more preferably 3 hours or more. By keeping the feed time in the reaction step of this application within the above range, a better reaction effect and higher efficiency can be achieved.

[0060] This application does not have any particular limitation on the gas atmosphere in which the trifluoromethyl sulfinate intermediate reacts with the alkali metal salt in an organic solvent, but it is preferred to carry out the reaction under the protection of an inert gas such as dry nitrogen or argon.

[0061] This application specifies that the equipment material used in the reaction of trifluoromethyl sulfinate intermediates and alkali metal salts in organic solvents can be any material that can be used in the manufacture of common chemicals, without any special limitations. However, considering the longevity of the equipment, the corrosiveness of the raw materials, and the generation of highly corrosive hydrogen fluoride gas during the hydrolysis of trifluoromethyl sulfinate, acid and alkali resistant materials other than glass are preferred.

[0062] This application does not impose any particular limitation on the weight ratio of the undesirable solvent to the trifluoromethyl sulfinate intermediate, but it is preferably 30 times or less by weight, more preferably 20 times or less, and even more preferably 10 times or less. Furthermore, the weight ratio of the undesirable solvent used in the crystallization process to the trifluoromethyl sulfinate is preferably 3 times or more, more preferably 2 times or more. Within the above range, a high yield from crystallization can be ensured, while also maintaining a good crystallization purification effect, resulting in trifluoromethyl sulfinate with good quality and performance.

[0063] This application does not have a particular limitation on the temperature at which unsuitable solvents are added for crystallization, but preferably it is below 25°C, more preferably below 10°C, and even more preferably below 15°C. Furthermore, the temperature at which unsuitable solvents are added for crystallization is preferably above -15°C, more preferably above -10°C, and even more preferably above -5°C. When the temperature at which unsuitable solvents are added for crystallization is within the above range, a large amount of trifluoromethyl sulfinate will not precipitate due to excessively low crystallization temperature.

[0064] This application does not limit the input time in the crystallization process of adding undesirable solvents, but it is preferably less than 6 hours, more preferably less than 4 hours, and even more preferably less than 2 hours. Furthermore, the input time in the crystallization process of adding undesirable solvents is preferably more than 1 minute, more preferably more than 10 minutes, and even more preferably more than 30 minutes. By keeping the input time of the reaction process within the above range, a relatively good crystallization and purification effect can be obtained while also achieving relatively high efficiency.

[0065] This application does not have any special restrictions on the solid-liquid separation method in the crystallization process with the addition of undesirable solvents. Crystallized trifluoromethyl sulfinate can be obtained by filtration methods such as reduced pressure filtration, pressurized filtration, and centrifugal filtration.

[0066] This application does not have a specific limitation on the temperature during solid-liquid separation after filtration following the addition of a poor solvent in the crystallization process. However, in order to improve the crystallization yield, it is preferable to be below 40°C, more preferably below 25°C, and even more preferably below 20°C. On the other hand, if the crystallization recovery yield is excessively increased, there is a risk of poor crystallization effect and decreased quality of the obtained trifluoromethyl sulfinate. Therefore, it is preferable to be above -20°C, more preferably above -10°C, and even more preferably above 0°C.

[0067] The trifluoromethyl sulfinate obtained through the above process contains residual organic solvents used in the process, and therefore is preferably removed by vacuum drying. Excessive temperature will cause the trifluoromethyl sulfinate to decompose thermally, while excessively low temperature may result in incomplete removal. The removal temperature is preferably below 80°C, more preferably below 60°C, and even more preferably below 40°C. Furthermore, a temperature of 10°C or higher is preferred, more preferably above 20°C, and even more preferably above 30°C. Longer drying times result in better removal, but also lead to decreased production efficiency. The drying time is preferably 40 minutes or more, more preferably 1 hour or more, and even more preferably 2 hours or more.

[0068] When an excess of alkali metal salt is used in the reaction, there may be a situation where the excess alkali metal salt remains as an insoluble component. This application does not specifically limit the method for removing the excess alkali metal salt as an insoluble component. Filtration methods such as vacuum filtration, pressure filtration, and centrifugal filtration can be used, followed by methods such as settling, centrifugation, and then taking out the supernatant. Furthermore, these methods can be combined or repeated.

[0069] This application does not specify a particular method for concentrating the reaction solution containing trifluoromethyl sulfinate after the reaction process and solid-liquid separation. Concentration can be achieved by atmospheric distillation or vacuum distillation. However, considering that unpredictable side reactions may occur at excessively high concentration temperatures, and that vacuum concentration often has higher concentration efficiency, this application preferably uses vacuum distillation to concentrate the reaction solution at temperatures below 80°C, more preferably below 60°C. There is no limitation on the lower limit of the vacuum degree. Considering the ease with which actual vacuum degrees can be achieved, the lower limit is preferably below -0.096 MPa, and further preferably below -0.1 MPa. There is no limitation on the upper limit of the vacuum degree. Considering the limitations of vacuum degree measurement and the actual achievable level of vacuum system equipment, it is preferably above -0.096 MPa, further preferably above -0.096 MPa, and even more preferably above -0.1 MPa.

[0070] The technical solution of the present invention will be further illustrated below through specific embodiments.

[0071] Example 1: This embodiment provides a method for preparing lithium trifluoromethyl sulfinate, including the following steps: (1) Weigh 33.6g of potassium hydroxide and 150g of ethanol into a 1000mL three-necked flask, turn on mechanical stirring, and start heating slowly. Under reflux at 90℃, add dropwise (prepared 81.5g of N-hydroxyphthalamide and 100g of ethanol mixture) in about 40min. Keep warm for 5h, take a sample for LC control, the raw materials react completely, and the purity of the target substance in the reaction solution is above 99%. After reaction, filter the reaction solution to remove excess KOH, concentrate the filtrate to recover ethanol, and obtain about 100g of solid. The obtained solid was placed in a 1000mL three-necked flask, and 300g of dichloromethane was added. The mixture was cooled in an ice-salt bath until the temperature dropped to -5℃. Then, 76.5g of trifluoromethyl sulfinyl chloride was added dropwise over approximately 30 minutes. The temperature was controlled between -5℃ and 5℃ and maintained at this temperature for 12 hours. A sample was taken for LC-controlled analysis to confirm that the reaction was complete. After post-reaction processing, the reaction solution was concentrated to obtain 176.5g (0.5mol) of solid trifluoromethyl sulfinic acid phthalimide ester, which was directly used for the hydrolysis reaction.

[0072] (2) The 1000 mL reaction vessel was purged three times with nitrogen. Then, 37 g (0.5 mol) of lithium carbonate, 10.8 g (0.6 mol) of pure water, and 400 g of ethylene glycol dimethyl ether were added sequentially to the vessel. The temperature was adjusted to 25°C, and then 176.5 g of phthalimide trifluoromethyl sulfinic acid was added in batches, maintaining the temperature between 25°C and 30°C. The addition was completed in approximately 40 minutes. The mixture was kept at this temperature for 5 hours. A sample was taken for LC analysis. The reaction was complete. After the reaction, insoluble matter was removed by filtration, yielding the reaction solution. The reaction formula is: .

[0073] (3) 482g of the reaction solution obtained in step (2) was concentrated under reduced pressure, with the vacuum degree controlled at -0.096Mpa and the temperature controlled at 60℃. When about 400g of dimethyl ethylene glycol dimethyl ether was distilled off, 160g of dichloromethane was added to the remaining material, and the temperature was lowered to -10℃ for dynamic crystallization. The wet product of lithium trifluoromethyl sulfinate was obtained by filtration. After drying at 40℃ for 2h, 65g of lithium trifluoromethyl sulfinate was obtained with a yield of about 93.8%. The purity was found to be above 99%, with chloride ion concentration of 10ppm and acid value of 45ppm (calculated as HF).

[0074] Example 2: This example provides a method for preparing sodium trifluoromethyl sulfinate, including the following steps: 33.6 g of potassium hydroxide and 150 g of methanol were weighed into a 1000 mL three-necked flask. Mechanical stirring was turned on, and the mixture was slowly heated to 90 °C under reflux. A mixture of 57.54 g of N-hydroxysuccinimide and 100 g of methanol was added dropwise over approximately 40 minutes. The mixture was kept at this temperature for 5 hours. The reaction was monitored by LC-MS, and the reaction was found to be complete. The purity of the target compound in the reaction solution was above 99%. Post-reaction processing was performed by filtering the reaction solution to remove excess KOH. The filtrate was concentrated to recover methanol, yielding approximately 76.54 g of solid. The obtained solid was placed in a 1000 ml three-necked flask, and 230 g of dichloromethane was added. The mixture was cooled in an ice-salt bath until the temperature dropped to -5 °C. Then, 76.5 g of trifluoromethyl sulfinyl chloride was added dropwise over 52 min. The temperature was controlled between -5 °C and 5 °C and kept at this temperature for 12 h. A sample was taken for LC-controlled analysis. The reaction was complete. After post-reaction processing, the reaction solution was concentrated to obtain 99.53 g (approximately 0.5 mol) of solid trifluoromethyl sulfinyl succinimide ester, which was directly used for the hydrolysis reaction.

[0075] (2) The 1000 mL reaction vessel was purged three times with nitrogen. 126 g (1.5 mol) of sodium bicarbonate and 350 g of ethyl acetate were added sequentially to the reaction vessel. The temperature was adjusted to 40°C, and then 99.53 g of trifluoromethyl sulfinic acid succinimide was added in batches, maintaining the temperature between 40°C and 50°C. The addition was completed in approximately 60 minutes. The mixture was kept at this temperature for 10 hours. A sample was taken for LC analysis. The reaction was complete. After the reaction was finished, the insoluble matter was removed by filtration, yielding the reaction solution. The reaction formula is: .

[0076] (3) The 455g obtained in step (2) was concentrated under reduced pressure, with the vacuum degree controlled at -0.097Mpa and the temperature controlled at 50℃. When about 350g of ethyl acetate was distilled off, 240g of dichloroethane was added to the remaining material, and the temperature was lowered to -5℃ for dynamic crystallization. The wet product of sodium trifluoromethyl sulfinate was obtained by filtration. After drying at 60℃ for 1h, 51.3g of sodium trifluoromethyl sulfinate was obtained, with a yield of about 95%. The purity was found to be above 99%, with chloride ion concentration of 9ppm and acid value of 35ppm (calculated as HF).

[0077] Example 3: This example provides a method for preparing potassium trifluoromethyl sulfinate, comprising the following steps: Weigh 33.6 g of potassium hydroxide and 150 g of ethanol into a 1000 mL three-necked flask, turn on mechanical stirring, and slowly heat to 90 °C under reflux. Add dropwise a pre-prepared mixture of 81.5 g of N-hydroxyphthalamide and 100 g of ethanol over approximately 40 minutes. Keep warm for 5 hours. Take a sample for LC-controlled analysis. The reaction was complete, and the purity of the target compound in the reaction solution was above 99%. Post-reaction processing: filter the reaction solution to remove excess KOH, concentrate the filtrate to recover ethanol, and obtain approximately 100 g of solid. The obtained solid was added to a 1000mL three-necked flask, and 300g of dichloromethane was added. The mixture was cooled in an ice-salt bath until the temperature dropped to -5℃. Then, 68g of trifluoromethyl sulfinyl fluoride was added dropwise over 53 minutes. The temperature was controlled between -5℃ and 5℃ and kept at this temperature for 13 hours. A sample was taken for LC-controlled analysis. The reaction was complete. After post-reaction processing, the reaction solution was concentrated to obtain 176.2g of solid trifluoromethyl sulfinic acid phthalimide ester, which was directly used for the hydrolysis reaction.

[0078] (2) The 1000 mL reaction vessel was purged three times with nitrogen. 56 g (2 mol) of potassium hydroxide and 450 g of dimethyl carbonate were added sequentially to the reaction vessel. After adjusting the temperature to 50°C, 176.2 g (approximately 0.5 mol) of phthalimide trifluoromethyl sulfinic acid was added in batches, with the temperature controlled between 50°C and 60°C. The addition was completed in approximately 48 minutes. The mixture was kept at this temperature for 15 hours. A sample was taken for LC analysis. The reaction was complete. After the reaction, insoluble matter was removed by filtration, yielding the reaction solution. The reaction formula is: .

[0079] (3) The 535g reaction solution obtained in step (2) was concentrated under reduced pressure, with the vacuum degree controlled at -0.1Mpa and the temperature controlled at 60℃. When about 450g of dimethyl carbonate was distilled off, 280g of dichloroethane was added to the remaining material, and the temperature was lowered to 0℃ for dynamic crystallization. The wet product of potassium trifluoromethyl sulfinate was obtained by filtration. After drying at 80℃ for 40min, 80g of potassium trifluoromethyl sulfinate was obtained, with a yield of about 93%. The purity was found to be above 99%, and the acid value was 30ppm (calculated as HF).

[0080] Example 4: This example provides a method for preparing lithium trifluoromethyl sulfinate, comprising the following steps: Weigh 33.6 g of potassium hydroxide and 150 g of ethanol into a 1000 mL three-necked flask, turn on mechanical stirring, and slowly heat to 90 °C under reflux. Add (prepared mixture of 81.5 g of N-hydroxyphthalamide and 100 g of methanol) dropwise over approximately 40 minutes. Keep warm for 5 hours. Take a sample for LC-controlled analysis. The reaction was complete, and the purity of the target compound in the reaction solution was above 99%. Post-reaction processing: filter the reaction solution to remove excess KOH, concentrate the filtrate to recover methanol, and obtain approximately 100 g of solid. The obtained solid was placed in a 1000 mL three-necked flask, and 300 g of dichloroethane was added. The mixture was cooled in an ice-salt bath until the temperature dropped to -5 °C. Then, 76.5 g of trifluoromethyl sulfinyl chloride was added dropwise over approximately 55 minutes. The temperature was maintained between -5 °C and 5 °C for 12 hours. A sample was taken for LC-controlled analysis to confirm the complete reaction of the raw materials. After post-reaction processing, the reaction solution was concentrated to obtain 176.0 g of solid trifluoromethyl sulfinic acid phthalimide ester, which was directly used for the hydrolysis reaction.

[0081] (2) The 1000 mL reaction vessel was purged three times with nitrogen. 52 g (1.3 mol) of lithium methoxide and 300 g of ethylene glycol dimethyl ether were added sequentially to the reaction vessel. After adjusting the temperature to 55°C, 176.0 g (0.5 mol) of phthalimide trifluoromethyl sulfinic acid was added in batches, with the temperature controlled between 50°C and 60°C, over approximately 50 minutes. The mixture was kept at this temperature for 9 hours. A sample was taken for LC analysis. The reaction was complete. After the reaction, insoluble matter was removed by filtration, yielding the reaction solution. The reaction formula is: .

[0082] (3) The 390g reaction solution obtained in step (2) was concentrated under reduced pressure, with the vacuum degree controlled at -0.1Mpa and the temperature controlled at 55℃. When about 300g of dimethyl ethylene glycol dimethyl ether was distilled off, 200g of dichloromethane was added to the remaining material, and the temperature was lowered to -5℃ for dynamic crystallization. The wet product of lithium trifluoromethyl sulfinate was obtained by filtration. After drying at 70℃ for 1.5h, 64g of lithium trifluoromethyl sulfinate was obtained, with a yield of about 91.4%. The purity was found to be above 99%, with chloride ion content of 7ppm and acid value of 38ppm (calculated as HF).

[0083] Example 5: This embodiment provides a method for preparing lithium trifluoromethyl sulfinate, including the following steps: 33.6 g of potassium hydroxide and 150 g of methanol were weighed into a 1000 mL three-necked flask. Mechanical stirring was turned on, and the mixture was slowly heated to 90 °C under reflux. A mixture of 42 g of N-hydroxymaleimide and 100 g of methanol was added dropwise over approximately 40 minutes. The mixture was kept at this temperature for 5 hours. The reaction was monitored by LC-MS, and the reaction was found to be complete. The purity of the target compound in the reaction solution was above 99%. After the reaction, the reaction solution was filtered to remove excess KOH, and the filtrate was concentrated to recover methanol, yielding approximately 61.5 g of solid. The obtained solid was placed in a 1000 mL three-necked flask, and 300 g of dichloroethane was added. The mixture was cooled in an ice-salt bath until the temperature dropped to -5 °C. Then, 76.5 g of trifluoromethyl sulfinyl chloride was added dropwise over approximately 55 minutes. The temperature was maintained between -5 °C and 5 °C for 12 hours. A sample was taken for LC-controlled analysis. The reaction was complete. After post-reaction processing, the reaction solution was concentrated to obtain 108.0 g of solid maleimide trifluoromethyl sulfinic acid, which was directly used for the hydrolysis reaction.

[0084] (2) The 2000 mL reaction vessel was purged three times with nitrogen. 63.59 g (1.5 mol) of lithium chloride and 450 g of vinylene carbonate were added sequentially to the reaction vessel. After adjusting the temperature to 55°C, 108.0 g (0.5 mol) of maleimide trifluoromethyl sulfinate was added in batches, with the temperature controlled between 50°C and 60°C, over approximately 50 minutes. The mixture was kept at this temperature for 9 hours. A sample was taken for LC analysis. The reaction was complete. After the reaction, insoluble matter was removed by filtration, yielding the reaction solution. The reaction formula is: (3) The 600.4g reaction solution obtained in step (2) was concentrated under reduced pressure, with the vacuum degree controlled at -0.1Mpa and the temperature controlled at 80℃. When about 450g of vinylene carbonate was distilled off, 300g of dichloromethane was added to the remaining material, and the temperature was lowered to -5℃ for dynamic crystallization. The wet product of lithium trifluoromethyl sulfinate was obtained by filtration and dried at 70℃ for 1.5h to obtain 65.5g of lithium trifluoromethyl sulfinate with a yield of about 93.5%. The purity was found to be above 99%, with chloride ion content of 10ppm and acid value of 30ppm (calculated as HF).

[0085] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0086] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0087] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A method for preparing trifluoromethyl sulfinate, characterized in that, include: Trifluoromethyl sulfinyl reagents are used to react with hydroxyl-containing amino compounds to obtain trifluoromethyl sulfinyl ester intermediates; The trifluoromethyl sulfinate intermediate is reacted with an alkali metal salt in an organic solvent to obtain the trifluoromethyl sulfinate.

2. The method for preparing trifluoromethyl sulfinate according to claim 1, characterized in that, The structural formula of the trifluoromethyl sulfinate intermediate is: ； Wherein, R is selected from any one of butyrylimide, maleimide, o-phenylbutyrylimide, and pyrazolide.

3. The method for preparing trifluoromethyl sulfinate according to claim 1, characterized in that, The reaction of the trifluoromethyl sulfinyl reagent with the hydroxyl-containing amino compound is carried out in a solvent selected from one or more of ethanol, methanol, propanol, dichloromethane, chloroform, 1,2-dichloroethane, tetrachloroethane, and chlorobenzene.

4. The method for preparing trifluoromethyl sulfinate according to claim 1, characterized in that, The method of obtaining trifluoromethyl sulfinyl ester intermediate by reacting a trifluoromethyl sulfinyl reagent with an amino compound containing a hydroxyl group includes: An alcohol-base is formed by reacting an amino compound containing a hydroxyl group with an inorganic base. The trifluoromethyl sulfinyl ester intermediate is obtained by reacting the alcohol base with a trifluoromethyl sulfinyl reagent.

5. The method for preparing trifluoromethyl sulfinate according to claim 4, characterized in that, The trifluoromethylsulfinyl reagent is selected from trifluoromethylsulfinyl chloride and / or trifluoromethylsulfinyl fluoride; and / or, The hydroxyl-containing amino compound is selected from the structure of [structure not specified]. N-hydroxysuccinimide, with the structural formula as follows N-hydroxyphthalimide, with the structural formula: N-hydroxymaleimide, with the structural formula as follows One or more of 1-hydroxypyrazoles.

6. The method for preparing trifluoromethyl sulfinate according to claim 1, characterized in that, The alkali metal salt is selected from at least one of alkali metal halide, alkali metal carbonate, alkali metal bicarbonate, oxides of alkali metals, hydroxides of alkali metals, or alcohols of alkali metals. The cation in the alkali metal salt is selected from at least one of lithium ions, sodium ions, or potassium ions.

7. The method for preparing trifluoromethyl sulfinate according to claim 6, characterized in that, The molar ratio of the cation in the alkali metal salt to the trifluoromethyl sulfinic acid ester intermediate is 1:1 to 4:

1.

8. The method for preparing trifluoromethyl sulfinate according to claim 1, characterized in that, The organic solvent is selected from aprotic solvents; The aprotic solvent is selected from at least one of chain carbonates, cyclic carbonates, chain carboxylic esters, chain ethers, or cyclic ether solvents.

9. The method for preparing trifluoromethyl sulfinate according to claim 8, characterized in that, The mass ratio of the organic solvent to the trifluoromethyl sulfinate intermediate is 3:1 to 8:

1.

10. The method for preparing trifluoromethyl sulfinate according to claim 1, characterized in that, The process of reacting the trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent to obtain trifluoromethyl sulfinate comprises: The reaction solution containing trifluoromethyl sulfinate was obtained by reacting the trifluoromethyl sulfinate intermediate with an alkali metal salt in an organic solvent. After concentrating the reaction solution, a poor solvent is added to obtain trifluoromethyl sulfinate solid; The undesirable solvent is selected from halogenated hydrocarbon solvents.

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