Preparation method of high-purity methyldisulfonate

Abstract

The invention belongs to the field of organic synthesis, provides a preparation method of high-purity methyldisulfonate, and solves the problems of low purity, high water content, high impurity metal ion content and poor product quality of methyldisulfonate in the prior art. The preparation method comprises the following steps: S1, reacting a methyldisulfonic acid crude product with a trialkylsilyl compound, and carrying out reduced pressure rectification to obtain methyldisulfonic acid bis-silyl ester; s2, the methyldisulfonic acid disilyl ester directly reacts with an alkaline metal compound, or the methyldisulfonic acid disilyl ester firstly reacts with water and / or alcohol to obtain high-purity methyldisulfonic acid, then the high-purity methyldisulfonic acid reacts with the alkaline metal compound to generate methyldisulfonate, and the high-purity methyldisulfonate is obtained after purification. According to the technical scheme, the problems existing in the prior art are well solved, and the additive can be used as an additive of a positive electrode, a negative electrode or an electrolyte of a secondary battery with high product quality requirements.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and in particular relates to a method for preparing high-purity methane disulfonate. Background Art

[0002] Methyl disulfonate is usually a powdered solid. Typical sodium dimethyl disulfonate is widely used as a main additive in the hard chrome electroplating process, and can also be used as an additive in the field of sodium batteries. Lithium dimethyl disulfonate can be used as a positive electrode material, a negative electrode material or an additive to the electrolyte of a lithium battery. For example, US2015 / 0155597 discloses a patent for lithium dimethyl disulfonate as a lithium ion battery additive. The amount added to the electrolyte is 0.001 to 0.2 wt%, which can significantly improve the charge and discharge efficiency and cycle performance of the lithium battery. However, the lithium dimethyl disulfonate mentioned in the patent is generated by in-situ reaction by adding dimethyl dimethyl disulfonate to the electrolyte, which will produce free acid, which will lead to deterioration of battery performance.

[0003] Regarding the preparation method of methyl disulfonate, the conventional method can be prepared by reacting methyl disulfonic acid with a hydroxide, carbonate, etc. of a metal in an aqueous solution, and then drying, purifying, etc. are performed on it in the later stage. However, the methyl disulfonate prepared by this method often contains a high content of impurity metal ions due to the quality and source restrictions of the raw material methyl disulfonic acid, and cannot meet the high quality requirements of the secondary battery for the additive. For example, Chinese patent CN1054371C discloses a process for preparing water-soluble methyl disulfonate, which includes four steps of sulfonation, bariumization, salt conversion, and concentration and drying. It uses dichloromethane and sodium sulfite as raw materials, reacts to prepare water-soluble sodium methyl disulfonate, and then treats the solution with barium chloride to obtain insoluble barium methyl disulfonate, and then reacts with water-soluble sulfate and barium methyl disulfonate to obtain water-soluble methyl disulfonate. However, the process of this method is complicated and cumbersome, and the content of impurity metal ions in the obtained product is high, and the product quality is poor, and it cannot be directly used as an additive for the positive electrode, negative electrode or electrolyte of a secondary battery.

[0004] Therefore, it is of great practical significance to develop a method for preparing a high-purity methane disulfonate that can be directly used as an additive for the positive electrode, negative electrode or electrolyte of a secondary battery. Summary of the invention

[0005] The purpose of the present invention is to solve the problems of low product purity, high water content and impurity metal ion content and poor product quality in the existing preparation process of methane disulfonate, and to provide a preparation method of high-purity methane disulfonate, which has the advantages of high purity, low water content, low impurity metal ion content and high product quality.

[0006] In order to achieve the above technical purpose, the technical solution adopted by the present invention is: to provide a method for preparing high-purity methane disulfonate, comprising the following steps:

[0007] S1: reacting crude methyl disulfonic acid with a trialkylsilyl compound, removing the reaction by-products in time during the reaction, and performing vacuum distillation after the reaction to obtain methyl disulfonic acid disilyl ester;

[0008] S2: Disilyl methyl disulfonate is directly reacted with an alkaline metal compound, or disilyl methyl disulfonate is first reacted with water and / or alcohol to obtain high-purity methyl disulfonic acid, which is then reacted with an alkaline metal compound to generate methyl disulfonate. After the reaction is completed, the product is separated and purified to obtain a high-purity methyl disulfonate product.

[0009] Furthermore, the trialkylsilyl compound described in step S1 is selected from at least one of hexaalkyldisiloxane, hexaalkyldisilazane, hexaalkyldisilurea, heptaalkyldisilazane, trialkylchlorosilane, trialkyloxysilane, trialkylacyloxysilane, trialkylsilylamine, trialkylsilylimidazole, trialkylamineoxysilane, trialkylalkenyloxysilane, trialkyloximesilane or N,O-bistrialkylsilylacetamide.

[0010] Furthermore, the trihydrocarbyl silicon-based compound described in step S1 is selected from at least one of hexamethyldisiloxane, trimethylchlorosilane, hexamethyldisilazane, heptamethyldisilazane, trimethylmethoxysilane, trimethylethoxysilane, trimethylsilylimidazole, hexamethyldisilurea or N,O-bistrimethylsilylacetamide.

[0011] Further, the alkaline metal compound described in step S2 is selected from at least one of lithium oxide, sodium oxide, potassium oxide, magnesium oxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, lithium methoxide, sodium methoxide, potassium methoxide, magnesium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, magnesium ethoxide, lithium isopropoxide, sodium isopropoxide, lithium tert-butoxide or sodium tert-butoxide.

[0012] Furthermore, the reaction temperature of step S1 is 20-150° C., the reaction time is 4-60 h, the molar ratio of the silicon element of the trialkylsilyl compound to the sulfonate in methyl disulfonic acid is 0.5-10:1, and the pressure of the vacuum distillation is 0.01-10 kPa.

[0013] Furthermore, the reaction temperature of step S1 is 40-110° C., the reaction time is 8-48 hours, and the molar ratio of the silicon element in the trialkylsilyl compound to the sulfonate in methyl disulfonic acid is 1-5:1.

[0014] Furthermore, in step S2, the reaction temperature is -10 to 100°C, the reaction time is 1 to 24 hours, and the molar ratio of the metal element in the alkaline metal compound to the sulfonic acid group of disiloxane or methyl disulfonic acid is 0.9 to 2.0:1.

[0015] Furthermore, in step S2, the reaction temperature is 25-60° C., and the reaction time is 4-24 h.

[0016] Furthermore, in step S2, a reaction solvent is used to promote dispersion, and the reaction solvent is selected from at least one of hydrocarbons, halogenated hydrocarbons, esters, ethers, ketones, nitriles, amides or sulfone solvents.

[0017] Furthermore, the reaction solvent used in step S2 is selected from at least one of toluene, cyclohexane, cyclopentane, dichloromethane, dichloroethane, chloroform, ethyl formate, ethyl acetate, propyl acetate, dimethyl carbonate, diethyl carbonate, ether, 1,3-dioxolane, 1,4-dioxane, acetone, acetonitrile, dimethylformamide or dimethyl sulfoxide.

[0018] Furthermore, in the step S2, after the reaction is completed, methyl disulfonate is obtained by filtering, washing, drying and recrystallization, and the product purity is ≥99%, and the single content of the main impurity metal ions does not exceed 20ppm.

[0019] The beneficial effects of the present invention are:

[0020] The invention provides a method for preparing high-purity methyl disulfonate through a large number of experimental studies. The method comprises the following steps: a crude methyl disulfonic acid product is reacted with a trialkylsilyl compound, and a transitional intermediate product methyl disulfonic acid disilyl ester is obtained by distillation. The disilyl ester is directly reacted with an alkaline metal compound, or is first hydrolyzed or alcoholyzed to obtain high-purity methyl disulfonic acid and then reacted with the alkaline metal compound to obtain methyl disulfonate. The silicon-containing byproduct can be reused. The obtained methyl disulfonate has high product quality and can meet the application requirements of the positive electrode, the negative electrode or the electrolyte additive of a secondary battery, etc., which have high requirements on the product quality of the methyl disulfonate.

[0021] Therefore, the preparation method of high-purity methane disulfonate provided by the present invention has the advantages of high product yield, high purity, low moisture content, low impurity metal ion content, green environmental protection, and low production cost, and has achieved good technical effects. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is the H NMR spectrum of bis(trimethylsilyl)methyl disulfonate in Example 1.

[0023] Figure 2 This is the H NMR spectrum of high-purity lithium methanedisulfonate in Example 1.

[0024] Figure 3 This is the H NMR spectrum of high-purity sodium methane disulfonate in Example 2.

[0025] Figure 4 This is the H NMR spectrum of the high-purity methanedisulfonic acid intermediate in Example 3. DETAILED DESCRIPTION

[0026] The technical solution of the present invention is further explained below in conjunction with specific implementation methods, but the following embodiments are only examples for explaining the present application and are not limitations on the content of the present application. Under the guidance of this specification, those skilled in the art may make improvements or modifications to the content of the present invention without creative contribution as needed, which all fall within the protection scope of the present invention.

[0027] Reaction temperature, unless otherwise specified, generally refers to the internal temperature of the reaction materials.

[0028] Reaction pressure, unless otherwise specified, generally refers to absolute pressure.

[0029] The purity of methanedisulfonic acid was checked by ion chromatography (IC).

[0030] The content of metal ions was detected by inductively coupled plasma emission spectrometry (ICP).

[0031] The yield is the percentage ratio of the actual product mass to the theoretical product mass, where the theoretical product mass is calculated based on the non-excess raw materials in the reaction equation.

[0032] The present application is further described in detail below in conjunction with embodiments.

[0033] [Example 1]

[0034] A method for preparing high-purity lithium methane disulfonate comprises the following steps:

[0035] S1: In a 5L reaction bottle equipped with nitrogen protection, magnetic stirring, thermometer, water separator, and reflux condenser, 1184.8g of methyl disulfonic acid product prepared by sulfur trioxide process (purity 59.5%, methanesulfonic acid content 1.1%, sulfuric acid content 18.3%, other impurities content 21.0%, Na + Content 35.0ppm, Ca 2+ Content 78.0ppm, Mg 2+ Content 8.1ppm, K + Content 7.2ppm, Fe 2+Content 75.6ppm), hexamethyldisiloxane 2593.6g, heating temperature, 96 ~ 110 ℃ reaction water separation 26h, water pump vacuum distillation, 3.3 ~ 4.5kPa recovery of excess hexamethyldisiloxane; switch rotary vane pump, vacuum distillation, collect 118 ~ 120 ℃ / 0.13kPa fraction, 1007.2g colorless transparent liquid, that is, methyl disulfonic acid bistrimethylsilyl ester, nuclear magnetic hydrogen spectrum determination results are 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 4.14 (-CH2-), 0.36 (-Si(CH3)3).

[0036]

[0037] S2: In a 500mL reaction bottle equipped with nitrogen protection, dropping funnel, magnetic stirring, thermometer, and reflux condenser, 8.4g of anhydrous lithium hydroxide and 300mL of dichloromethane were added, and 56.4g of bistrimethylsilyl methyl disulfonate was added dropwise under ice water cooling, and the internal temperature was maintained at 10-15°C. After the addition was completed, the temperature was raised and the reaction was continued at 30-35°C for 8h. After the reaction was completed, the filter was filtered and the filter cake was washed with dichloromethane. The filter cake was transferred to a rotary evaporator and dried at 75-80°C / 0.1-0.3kPa for 24h to obtain 30.6g of white powder, which was lithium methyl disulfonate product, with a yield of 92.6%, a product purity of 99.5%, a moisture content of 234ppm, and metal ion content test results (Li, Al, Ca, Fe, K, Mg, Na, Zn, Cr, Cu, Pb) were: Li + Content 7.40%, Na + Content 15.3ppm, Al 3+ Content 10.7ppm, K + Content 12.4ppm, Ca 2+ Content 3.9ppm, Fe 2+ Content 1.5ppm, Mg 2+ The content is 1.7ppm, and the rest is <1ppm; the results of nuclear magnetic hydrogen spectrum are 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 3.66 (-CH2-).

[0038]

[0039] [Example 2]

[0040] A method for preparing high-purity sodium methane disulfonate comprises the following steps:

[0041] S1: In a 3L reaction bottle equipped with nitrogen protection, magnetic stirring, thermometer, reflux condenser, and tail gas absorption device, 733.6g of commercially available methanedisulfonic acid product (content 96%, water content 0.18%, Na + Content 3025ppm, Ca 2+ Content 178ppm, Mg 2+ Content 11.1ppm, K + Content 11.2ppm, Fe 2+ The content was 7.65ppm), hexamethyldisilazane 1936.8g, heated to 105-110℃ for 30h, and the by-product ammonia was absorbed in time during the reaction; the water pump was used for vacuum distillation, and the excess hexamethyldisilazane was recovered at 3.3-4.5kPa; the rotary vane pump was switched for vacuum distillation, and the 118-120℃ / 0.13kPa fraction was collected to obtain 1161.6g of colorless transparent liquid, namely bistrimethylsilyl dimethylsulfonate, and the results of H NMR spectrum determination were 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 4.14 (-CH2-), 0.36 (-Si(CH3)3).

[0042]

[0043] S2: In a 1L reaction bottle equipped with nitrogen protection, dropping funnel, magnetic stirring, thermometer, and reflux condenser, 47.7g of anhydrous sodium carbonate and 300mL of ethyl acetate were added, and 96.0g of bis(trimethylsilyl)methyl disulfonate was added dropwise under ice water cooling, and the internal temperature was maintained at 10-15°C. After the addition was completed, the temperature was raised and the reaction was continued at 50-50°C for 4h. After the reaction was completed, the filter was filtered and the filter cake was washed with ethyl acetate. The filter cake was transferred to a rotary evaporator and dried at 75-80°C / 0.1-0.3kPa for 24h to obtain 62.6g of white powder, which was sodium disulfonate product, with a yield of 94.4%, a product purity of 99.6%, a moisture content of 185ppm, and metal ion content test results (Na, Al, K, Ca, Fe, Mg, Zn, Cr, Cu, Pb) were: Na + Content 20.81%, Ca 2+ Content 5.1ppm, K + Content 5.6ppm, Al 3 + Content 4.9ppm, Fe 2+ The content is 1.5ppm, and the rest is <1ppm; the results of nuclear magnetic hydrogen spectrum determination are 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 3.67 (-CH2-).

[0044]

[0045] [Example 3]

[0046] A method for preparing high-purity potassium methane disulfonate comprises the following steps:

[0047] S1: In a 5L reaction bottle equipped with nitrogen protection, magnetic stirring, thermometer, water separator, and reflux condenser, 1699.0g of methyl disulfonic acid product prepared by sulfur trioxide process (purity 61.8%, methanesulfonic acid content 1.5%, sulfuric acid content 17.6%, other impurities content 19.0%, Na + Content 41.0ppm, Ca 2+ Content 77.3ppm, Mg 2+ Content 9.3ppm, K + Content 9.9ppm, Fe 2+ The content was 84.0ppm), trimethylmethoxysilane 1891.5g, heated to 57-60℃ for 35h, and the by-product methanol was removed in time during the reaction; the water pump was used for vacuum distillation, and the excess trimethylmethoxysilane was recovered at 3.3-4.5kPa; the rotary vane pump was switched for vacuum distillation, and the 136-138℃ / 0.35kPa fraction was collected to obtain 1365.5g of colorless transparent liquid, which was bistrimethylsilyl disulfonate. The results of H NMR spectrum were as follows: 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 4.14 (-CH2-), 0.36 (-Si(CH3)3).

[0048]

[0049] S2: In a 1L reaction bottle equipped with a magnetic stirrer, a thermometer, and a reflux condenser, add 273.1g of bis(trimethylsilyl)methyl disulfonate and 500mL of dichloroethane, add 81.6g of methanol dropwise at room temperature, heat to 50-55°C for 12h, and distill under reduced pressure with a water pump to recover the solvent and the by-product trimethylmethoxysilane; switch to a rotary vane pump, dry on a rotary evaporator at 75-80°C / 0.3kPa for 24h, and obtain 143.0g of white crystals of methyl disulfonic acid with a purity of 99.6%. The results of H NMR spectrum determination are 1H-NMR (400MHz, DMSO-d6) δ (ppm): 3.82 (-CH2-), 11.09 (-SO3H); 135.3g of anhydrous potassium carbonate and 600mL of dimethyl carbonate were added to the reaction bottle, and the reaction was carried out at 40-45°C for 6h. After the reaction was completed, the mixture was filtered, and the filter cake was washed with dimethyl carbonate. The filter cake was transferred to a rotary evaporator and dried at 75-80°C / 0.1-0.3kPa for 24h to obtain 194.3g of white powder, i.e. potassium methyl disulfonate product, with a yield of 94.9%, a product purity of 99.6%, a moisture content of 156ppm, and metal ion content test results (Li, Na, Al, K, Ca, Fe, Mg, Zn, Cr, Cu, Pb) were as follows: K + Content 31.01%, Al 3+ Content 9.0ppm, Na + Content 12.7ppm, Ca 2+ Content 3.4ppm, Fe 2+ Content 1.5ppm, Mg 2+ The content is 1.2ppm, and the rest is <1ppm; the results of nuclear magnetic hydrogen spectrum are 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 3.66 (-CH2-).

[0050]

[0051] [Example 4]

[0052] A method for preparing high-purity magnesium methane disulfonate comprises the following steps:

[0053] S1: In a 5L reaction bottle equipped with nitrogen protection, magnetic stirring, thermometer, reflux condenser, and tail gas absorption device, 757.6g of commercially available methanedisulfonic acid product (content 93%, water content 0.20%, Na + Content 2963ppm, Ca 2+ Content 189ppm, Mg 2+ Content 12.9ppm, K + Content 11.1ppm, Fe 2+ The content was 12.7ppm), trimethylchlorosilane 1737.6g, heated to 40-57℃ for 8h, and the by-product HCl gas was absorbed in time during the reaction; the water pump was used for vacuum distillation, and the excess trimethylchlorosilane was recovered at 3.3-4.5kPa; the rotary vane pump was switched for vacuum distillation, and the 118-120℃ / 0.13kPa fraction was collected to obtain 1235.2g of colorless transparent liquid, which was bistrimethylsilyl disulfonate. The results of H NMR spectrum were as follows: 1H-NMR (400MHz, DMSO-d6) δ (ppm): 4.14 (-CH2-), 0.36 (-Si(CH3)3).

[0054]

[0055] S2: In a 1L reaction bottle equipped with nitrogen protection, dropping funnel, magnetic stirring, thermometer, and reflux condenser, add 153.7g of bistrimethylsilyl dimethyl disulfonate and 200mL of dichloromethane, add 17.3g of pure water dropwise at room temperature, heat and react at 30-35℃ for 16h, and distill under reduced pressure with a water pump to recover the solvent and the by-product hexamethyldisiloxane; switch to a rotary vane pump, dry on a rotary evaporator at 75-80℃ / 0.3kPa for 24h, and obtain 79.1g of white crystals of methyl disulfonic acid with a purity of 99.6%. The results of H NMR spectrum determination are 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 3.82 (-CH2-), 11.09 (-SO3H); 28.7 g of anhydrous magnesium hydroxide and 300 mL of diethyl carbonate were added to the reaction flask, and the reaction was continued at 55-60°C for 6 h. After the reaction was completed, the mixture was filtered, and the filter cake was washed with diethyl carbonate. The filter cake was transferred to a rotary evaporator and dried at 75-80°C / 0.1-0.3 kPa for 24 h to obtain 83.2 g of white powder, i.e., magnesium methyl disulfonate product, with a yield of 93.0%, a product purity of 99.2%, a moisture content of 357 ppm, and metal ion content test results (Na, Al, K, Ca, Fe, Mg, Zn, Cr, Cu, Pb) were as follows: Mg 2+ Content 12.21%, Na + Content 13.8ppm, K + Content 11.4ppm, Ca 2+ Content 4.7ppm, Al 3+ Content 3.9ppm, Fe 2+ The content is 1.2ppm, and the rest is <1ppm; the results of nuclear magnetic hydrogen spectrum are 1 H-NMR (400MHz, DMSO-d6) δ (ppm): 3.67 (-CH2-).

[0056]

[0057]

[0058] In summary, the preparation method of high-purity methyl disulfonate provided by the present invention comprises the following steps: reacting crude methyl disulfonic acid with a trialkylsilyl compound, and distilling to obtain a transitional intermediate product, methyl disulfonic acid disilyl ester, and the disilyl ester directly reacts with an alkaline metal compound, or is first hydrolyzed or alcoholyzed to obtain high-purity methyl disulfonic acid and then reacts with an alkaline metal compound to obtain high-purity methyl disulfonate, which has high yield, high purity, low moisture content, and low impurity metal ion content, and the process is green and environmentally friendly, with low production cost, and can meet the application requirements of the positive electrode, negative electrode or electrolyte additive of secondary batteries, etc., which have high requirements on the quality of methyl disulfonate products.

Claims

1. A method for preparing high-purity methane disulfonate, comprising the following steps: S1: reacting crude methyl disulfonic acid with a trialkylsilyl compound, removing the reaction by-products in time during the reaction, and performing vacuum distillation after the reaction to obtain methyl disulfonic acid disilyl ester; S2: Disilyl methyl disulfonate is directly reacted with an alkaline metal compound, or disilyl methyl disulfonate is first reacted with water and / or alcohol to obtain high-purity methyl disulfonic acid, which is then reacted with an alkaline metal compound to generate methyl disulfonate. After the reaction is completed, the product is separated and purified to obtain a high-purity methyl disulfonate product.

2. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The trialkylsilyl compound described in step S1 is selected from at least one of hexaalkyldisiloxane, hexaalkyldisilazane, hexaalkyldisilurea, heptaalkyldisilazane, trialkylchlorosilane, trialkyloxysilane, trialkylacyloxysilane, trialkylsilylamine, trialkylsilylimidazole, trialkylamineoxysilane, trialkylalkenyloxysilane, trialkyloximesilane or N,O-bistrialkylsilylacetamide.

3. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The trihydrocarbylsilyl compound described in step S1 is selected from at least one of hexamethyldisiloxane, trimethylchlorosilane, hexamethyldisilazane, heptamethyldisilazane, trimethylmethoxysilane, trimethylethoxysilane, trimethylsilylimidazole, hexamethyldisilurea or N,O-bistrimethylsilylacetamide.

4. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The alkaline metal compound described in step S2 is typically selected from at least one of lithium oxide, sodium oxide, potassium oxide, magnesium oxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, magnesium hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, magnesium carbonate, lithium methoxide, sodium methoxide, potassium methoxide, magnesium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, magnesium ethoxide, lithium isopropoxide, sodium isopropoxide, lithium tert-butoxide or sodium tert-butoxide.

5. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The reaction temperature of step S1 is 20-150°C, the reaction time is 4-60h, the molar ratio of the silicon element in the trialkylsilyl compound to the sulfonate group in methyl disulfonic acid is 0.5-10:1, and the pressure of the vacuum distillation is 0.01-10kPa; the reaction temperature of step S2 is -10-100°C, the reaction time is 1-24h, and the molar ratio of the metal element in the alkaline metal compound to the sulfonic acid group of disilyl methyl disulfonate or methyl disulfonic acid is 0.9-2.0:

1.

6. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The reaction temperature of step S1 is 40-110° C., the reaction time is 8-48 hours, and the molar ratio of the silicon element of the trialkylsilyl compound to the sulfonate group in methyl disulfonic acid is 1-5:1; the reaction temperature of step S2 is 25-60° C., and the reaction time is 4-24 hours.

7. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The step S2 uses a reaction solvent to promote dispersion, and the reaction solvent is selected from at least one of hydrocarbons, halogenated hydrocarbons, esters, ethers, ketones, nitriles, amides or sulfone solvents.

8. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: The step S2 uses a reaction solvent to promote dispersion, and the reaction solvent is selected from at least one of toluene, cyclohexane, cyclopentane, dichloromethane, dichloroethane, chloroform, ethyl formate, ethyl acetate, propyl acetate, dimethyl carbonate, diethyl carbonate, ether, 1,3-dioxolane, 1,4-dioxane, acetone, acetonitrile, dimethylformamide or dimethyl sulfoxide.

9. The method for preparing high-purity methane disulfonate according to claim 1, characterized in that: After the reaction in step S2 is completed, methyl disulfonate is obtained after filtering, washing, drying and recrystallization. The product purity is ≥99%, and the single content of the main impurity metal ions does not exceed 20ppm.

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