A preparation method of methanesulfonate products

Abstract

The invention discloses a method for preparing a methanesulfonate product. The method comprises the following steps: in a dichloromethane system, the reaction temperature is controlled to be no higher than 40°C and the reaction rate is controlled, a mixed solution of methanesulfonyl chloride and methanesulfonic anhydride reacts with sodium alkoxide, after the reaction is completed, the reaction solution is cooled to room temperature, filtered, dried, and subjected to rotary evaporation to remove the solvent, and distilled to obtain the methanesulfonate product. The method has a simple synthesis route, does not use an acid binding agent, a phase transfer catalyst or an esterification catalyst, does not require heating, has a short reaction time, and greatly reduces the total production cost in terms of raw materials, production cycle, environmental protection, and the like. The yield and purity of the product prepared by the method are very high, with the yield reaching above 98.2% and the purity reaching above 99.9%. The moisture content of the obtained product is also very low, and the quality of the product obtained by the method far exceeds the product standard for use as an electrolyte.

Description

Technical Field

[0001] The present invention relates to the technical field of battery electrolytes, and in particular to a method for preparing a methanesulfonate product. Background Art

[0002] Lithium batteries are primarily composed of four major components: cathode material, anode material, diaphragm material, and electrolyte. The electrolyte is often called the lifeblood of lithium batteries, and its composition is closely linked to their high- and low-temperature performance, charge and discharge cycles, capacity, and safety. For example, when the battery is used at high temperatures, the electrolyte's increased activity triggers a vigorous redox reaction at the cathode and anode. This, along with the resulting gasses from these side reactions, can lead to battery expansion, damage, and even electrolyte leakage, which can lead to fires and other safety incidents.

[0003] Sulfonate esters contain epoxy functional groups, which, due to the tension in their ring structures, impart high reactivity and oxidation potential. Consequently, they exhibit greater oxidation resistance at high potentials than double bonds. Furthermore, the carbon-oxygen bond within epoxy functional groups positively impacts the wettability of the electrolyte within the overall battery system. Therefore, the use of sulfonate esters as non-aqueous organic solvents, or in combination with other non-aqueous organic solvents, can help improve battery safety at high temperatures.

[0004] The synthetic route for preparing sulfonate esters generally involves esterification of sulfonyl chlorides or sulfonic acids with alcohols in the presence of an acid-binding agent or catalyst to produce the corresponding sulfonate esters. This type of reaction not only takes a long time but also requires the use of catalysts or acid-binding agents, resulting in high overall production costs. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a mesylate product, which does not use a catalyst or an acid-binding agent, has a short reaction time, low production cost, and is more suitable for industrial promotion.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing a mesylate product, the key of which is to control the reaction temperature to no more than 40°C and the reaction rate in a dichloromethane system to react a mixed solution of methanesulfonyl chloride and methanesulfonic anhydride with sodium alkoxide. After the reaction is completed, the reaction solution is cooled to room temperature, filtered, dried, and subjected to rotary evaporation to remove the solvent, and then distilled to obtain the mesylate product.

[0007] Furthermore, the specific operation of controlling the reaction temperature to not be higher than 40°C is as follows: placing the reaction system in an ice-water bath to control the reaction temperature at 25°C to 40°C.

[0008] Furthermore, the specific operation of controlling the reaction rate is as follows: adding a mixed solution of methanesulfonyl chloride and methanesulfonic anhydride or sodium alkoxide to the dichloromethane system in a dropwise manner.

[0009] Specifically, stirring is required during the dropwise addition process.

[0010] More specifically, the above-mentioned distillation is carried out as follows: a glass fiber packing column with a length of 20 cm to 30 cm is used as a distillation device, a diaphragm pump is used to evacuate the column, and the reaction solution is heated to 95° C. to 130° C. to obtain the product by distillation.

[0011] Preferably, the molar ratio of the methanesulfonyl chloride to the sodium alkoxide is 1:1-2, and the molar ratio of the methanesulfonyl chloride to the methanesulfonic anhydride is 1:0.001-1.

[0012] Preferably, the reaction time of the above reaction is 20 min to 1 h.

[0013] The above content also includes a preparation process of a mixed solution of methanesulfonyl chloride and methanesulfonic anhydride: adding methanesulfonic acid to a reaction flask, stirring, heating to 100°C to 110°C, adding thionyl chloride dropwise, after the reaction is completed, vacuum distilling to remove excess thionyl chloride, concentrating the reaction solution, vacuum distilling, and heating distillation, collecting the fraction at 70°C to obtain methanesulfonyl chloride, collecting the fraction at 120°C to 150°C to obtain methanesulfonic anhydride, and dissolving the methanesulfonyl chloride and methanesulfonic anhydride in dichloromethane.

[0014] Specifically, the sodium alkoxide is one of sodium methoxide, sodium ethoxide, sodium propoxide, sodium methoxide methanol solution, sodium ethoxide ethanol solution or sodium propoxide propanol solution.

[0015] More specifically, the sodium propoxide includes sodium n-propoxide and sodium isopropoxide, and the sodium propoxide propanol solution includes a n-propanol solution of sodium n-propoxide and an isopropanol solution of sodium isopropoxide.

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] The synthetic route of the present invention is simple, does not use an acid binding agent, a phase transfer catalyst or an esterification catalyst, does not require heating, and can synthesize a series of mesylate products. Moreover, the reaction time is very short, which not only reduces production costs in terms of raw materials, but also shortens the production cycle of the product. The methanesulfonic anhydride involved in the present invention can also be recycled, greatly reducing the total production cost. Furthermore, no waste salt is generated during production, thereby reducing the investment in environmental protection.

[0018] The various mesylate products prepared by the present invention have very high yields and purities, with yields exceeding 98.2% and reaching a maximum of 98.8%. The purities of the various products can reach above 99.9%, with a maximum of 99.97%. Furthermore, the products obtained by the present invention have very low moisture content, with the moisture content being controlled to a minimum of 42 mg / kg. The quality of the products obtained by the present invention far exceeds the standards for use as electrolytes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 is a photograph of Sample 1 prepared in Example 1 of the present invention;

[0020] Figure 2 is the H NMR spectrum of sample 1 prepared in Example 1 of the present invention;

[0021] Figure 3 is the H NMR spectrum of sample 3 prepared in Example 3 of the present invention;

[0022] Figure 4 is the H NMR spectrum of sample 5 prepared in Example 5 of the present invention;

[0023] Figure 5 is the gas chromatography-mass spectrometer of sample 1 prepared in Example 1 of the present invention;

[0024] Figure 6 is the gas chromatography-mass spectrometer of sample 3 prepared in Example 3 of the present invention;

[0025] Figure 7 is the gas chromatography-mass spectrometer of sample 5 prepared in Example 5 of the present invention;

[0026] Figure 8 This is the impurity analysis spectrum of sample 5 prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0027] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0028] For the convenience of description, the amounts of test materials used in the embodiments and comparative examples are all pure amounts.

[0029] Example 1

[0030] S1: Preparation of methanesulfonyl chloride and methanesulfonic anhydride:

[0031] S1-1: Place the dry reaction bottle in an oil bath with magnetic stirring, install a thermometer and a condenser, connect the condenser to a drying tube, and connect it to condensing water;

[0032] S1-2: Add 8.0 g of methanesulfonic acid to the reaction flask, start stirring, add 12.0 g of thionyl chloride to the constant pressure dropping funnel, raise the temperature to 100°C, and slowly add thionyl chloride dropwise;

[0033] S1-3: After the addition of thionyl chloride is complete, the residual methanesulfonic acid is detected by gas chromatography. The reaction ends when no methanesulfonic acid is detected.

[0034] S1-4: Excess thionyl chloride is removed by vacuum distillation, and the reaction solution is then concentrated, vacuum distilled, and evacuated using a diaphragm pump. The reaction solution is heated to 70°C and distilled. The distillation process is monitored using gas chromatography, and the fractions are collected. The collected fractions are methanesulfonyl chloride.

[0035] S1-5: Continue to slowly raise the temperature to 150°C, perform heating distillation, use gas chromatography to control the distillation process, and collect the fraction at 120°C to 150°C, which is methanesulfonic anhydride;

[0036] S1-6: Prepare sufficient amounts of methanesulfonyl chloride and methanesulfonic anhydride according to the above steps.

[0037] S2: Preparation of mesylate esters:

[0038] S2-1: Place the dry reaction bottle in an ice-water bath with magnetic stirring, install a thermometer and a condenser, connect the condenser to the drying tube, and connect it to the condenser water;

[0039] S2-2: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride and 0.009 g (equivalent to 0.000052 mol) of methanesulfonic anhydride prepared in step S1 were washed into a reaction flask with 100 mL of dichloromethane. The mixture was stirred and 100 mL of a methanol solution containing 2.8 g (equivalent to 0.052 mol) of sodium methoxide was added dropwise in an ice-water bath. The addition rate of the methanol solution of sodium methoxide was controlled to maintain the temperature of the reaction solution at 30°C.

[0040] S2-3: After the addition is complete, the content of methanesulfonic anhydride and methanesulfonyl chloride is detected using a gas chromatograph. When the starting material is not detected, the reaction is terminated. The reaction time is 30 minutes, and the reaction solution is allowed to cool to room temperature;

[0041] S2-4: Use a diaphragm pump to filter the reaction liquid, dry the filtrate with anhydrous magnesium sulfate, and rotary evaporate until no solvent is extracted to obtain a reaction concentrate. Distill it under vacuum conditions using a 25 cm long glass fiber packing column, set the heating distillation at 100°C to 120°C, and collect the fractions to obtain methyl methanesulfonate product, i.e., Sample 1.

[0042] Example 2

[0043] S1: Preparation of methanesulfonyl chloride and methanesulfonic anhydride: The same as step S1 of Example 1, except that the reaction temperature of step S1-2 is 105°C.

[0044] S2: Preparation of mesylate esters:

[0045] S2-1: Same as step S2-1 of Example 1;

[0046] S2-2: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride and 0.018 g (equivalent to 0.00010 mol) of methanesulfonic anhydride prepared in step S1 were added to 90 mL of dichloromethane to prepare a dichloromethane solution of methanesulfonyl chloride and methanesulfonic anhydride. 2.8 g (equivalent to 0.052 mol) of sodium methoxide was added to the reaction flask, stirred, and the dichloromethane solution of methanesulfonyl chloride and methanesulfonic anhydride was added dropwise in an ice-water bath while controlling the dropwise addition rate to maintain the temperature of the reaction solution at 40°C.

[0047] S2-3: Same as step S2-3 of Example 1, except that the reaction time is 20 min when the reaction is terminated, and the reaction solution is allowed to cool to room temperature;

[0048] S2-4: Use a diaphragm pump to filter the reaction liquid, dry the filtrate with anhydrous magnesium sulfate, and rotary evaporate until no solvent is extracted to obtain a reaction concentrate. Distill it under vacuum conditions using a 30 cm long glass fiber packing column, set the heating distillation temperature at 95°C to 115°C, and collect the fractions to obtain methyl methanesulfonate product, i.e., Sample 2.

[0049] Example 3

[0050] S1: Preparation of methanesulfonyl chloride and methanesulfonic anhydride: The same as step S1 of Example 1, except that the reaction temperature of step S1-2 is 110°C.

[0051] S2: Preparation of mesylate esters:

[0052] S2-1: Same as step S2-1 of Example 1;

[0053] S2-2: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride and 9.1 g (equivalent to 0.052 mol) of methanesulfonic anhydride prepared in step S1 were washed into a reaction flask with 110 mL of dichloromethane. The mixture was stirred and 120 mL of an ethanol solution containing 7.1 g (equivalent to 0.104 mol) of sodium ethoxide was added dropwise in an ice-water bath. The addition rate of the ethanol solution of sodium ethoxide was controlled to maintain the temperature of the reaction solution at 25°C.

[0054] S2-3: Same as step S2-3 of Example 1, except that the reaction time is 40 min at the end of the reaction, and the reaction solution is allowed to cool to room temperature;

[0055] S2-4: Use a diaphragm pump to filter the reaction liquid, dry the filtrate with anhydrous magnesium sulfate, and rotary evaporate until no solvent is extracted to obtain a reaction concentrate. Distill it under vacuum conditions using a 30 cm long glass fiber packing column, set the heating distillation temperature at 110°C to 120°C, and collect the fractions to obtain ethyl methanesulfonate product, i.e., Sample 3.

[0056] Example 4

[0057] S1: Preparation of methanesulfonyl chloride and methanesulfonic anhydride: The same as step S1 of Example 1, except that the reaction temperature of step S1-2 is 105°C.

[0058] S2: Preparation of mesylate esters:

[0059] S2-1: Same as step S2-1 of Example 1;

[0060] S2-2: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride and 7.2 g (equivalent to 0.042 mol) of methanesulfonic anhydride prepared in step S1 were added to 100 mL of dichloromethane to prepare a dichloromethane solution of methanesulfonyl chloride and methanesulfonic anhydride. 6.4 g (equivalent to 0.094 mol) of sodium ethoxide was added to the reaction flask, stirred, and the dichloromethane solution of methanesulfonyl chloride and methanesulfonic anhydride was added dropwise in an ice-water bath while controlling the dropwise addition rate to maintain the temperature of the reaction solution at 40°C.

[0061] S2-3: Same as step S2-3 of Example 1, except that the reaction time is 30 min at the end of the reaction, and the reaction solution is allowed to cool to room temperature;

[0062] S2-4: Use a diaphragm pump to filter the reaction liquid, dry the filtrate with anhydrous magnesium sulfate, and evaporate it until no solvent is extracted to obtain a reaction concentrate. Distill it under vacuum conditions using a 25 cm long glass fiber packing column, set the heating distillation temperature at 120°C to 130°C, and collect the fractions to obtain ethyl methanesulfonate product, i.e., Sample 4.

[0063] Example 5

[0064] S1: Preparation of methanesulfonyl chloride and methanesulfonic anhydride: same as step S1 in Example 1.

[0065] S2: Preparation of mesylate esters:

[0066] S2-1: Same as step S2-1 of Example 1;

[0067] S2-2: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride and 2.7 g (equivalent to 0.016 mol) of methanesulfonic anhydride prepared in step S1 were added to 90 mL of dichloromethane to prepare a dichloromethane solution of methanesulfonyl chloride and methanesulfonic anhydride. 6.4 g (equivalent to 0.078 mol) of sodium n-propoxide was added to the reaction flask, stirred, and the dichloromethane solution of methanesulfonyl chloride and methanesulfonic anhydride was added dropwise in an ice-water bath while controlling the dropwise addition rate to maintain the temperature of the reaction solution at 35°C.

[0068] S2-3: Same as step S2-3 of Example 1, except that the reaction time is 45 min at the end of the reaction, and the reaction solution is allowed to cool to room temperature;

[0069] S2-4: Use a diaphragm pump to filter the reaction liquid, dry the filtrate with anhydrous magnesium sulfate, and rotary evaporate until no solvent is extracted to obtain a reaction concentrate. Distill it under vacuum conditions using a 20 cm long glass fiber packing column, set the heating distillation at 100°C ~ 115°C, and collect the fractions to obtain propyl methanesulfonate product, i.e., Sample 5.

[0070] Example 6

[0071] S1: Preparation of methanesulfonyl chloride and methanesulfonic anhydride: same as step S1 in Example 1.

[0072] S2: Preparation of mesylate esters:

[0073] S2-1: Same as step S2-1 of Example 1;

[0074] S2-2: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride and 4.5 g (equivalent to 0.026 mol) of methanesulfonic anhydride prepared in step S1 were washed into a reaction flask with 100 mL of dichloromethane. The mixture was stirred, and 80 mL of an isopropanol solution of 5.5 g (equivalent to 0.068 mol) of sodium isopropoxide was added dropwise in an ice-water bath. The addition rate of the isopropanol solution of sodium isopropoxide was controlled to maintain the temperature of the reaction solution at 30°C.

[0075] S2-3: Same as step S2-3 of Example 1, except that the reaction time is 1 h at the end of the reaction, and the reaction solution is allowed to cool to room temperature;

[0076] S2-4: Use a diaphragm pump to filter the reaction liquid, dry the filtrate with anhydrous magnesium sulfate, and rotary evaporate until no solvent is extracted to obtain a reaction concentrate. Distill it under vacuum conditions using a 20 cm long glass fiber packing column, set the heating distillation temperature at 115°C ~ 130°C, and collect the fractions to obtain the isopropyl methanesulfonate product, i.e., Sample 6.

[0077] Comparative Example

[0078] Comparative Example 1

[0079] S1: The implementation process is the same as step S1 in Example 1;

[0080] S2: The implementation process is the same as step S2 of Example 1, except that the dropping rate of the methanol solution of sodium methoxide is adjusted in step S2-2 to keep the reaction temperature at 60°C, and the reaction time in step S2-3 is 5 min to prepare a methyl methanesulfonate reference substance, i.e., reference substance 1.

[0081] Comparative Example 2

[0082] S1: The implementation process is the same as step S1 in Example 1;

[0083] S2: The implementation process is the same as step S2 of Example 1, except that step S2-1 does not require a condensing apparatus, and the specific operation of step S2-2 is as follows: 6.0 g (equivalent to 0.052 mol) of methanesulfonyl chloride prepared in step S1 is taken, and methanesulfonic anhydride is not added. The methanesulfonyl chloride is washed into a reaction flask with 100 mL of dichloromethane and stirred. 10.5 g (equivalent to 0.104 mol) of triethylamine is added, 2.5 g (equivalent to 0.078 mol) of methanol is added, and 0.25 g (equivalent to 0.00104 mol) of tetrabutylammonium bromide is added. The reaction solution is heated to maintain the temperature at 60° C. and refluxed. The content of methanesulfonic anhydride is detected by gas chromatograph. When the starting material is not detected, the reaction is terminated. The reaction time is recorded as 6 h. The reaction solution is allowed to cool to room temperature. Methyl methanesulfonate reference substance, i.e., reference substance 2, is prepared through step S2-4.

[0084] Analysis and testing

[0085] The prepared samples are all colorless, transparent liquids at room temperature and pressure. The photo of sample 1 prepared in Example 1 is shown in the attached Figure 1 The purity and moisture content of the samples are much higher than the relevant product standards (purity ≥ 99.5%, moisture ≤ 200mg / kg). For the specific test report, please refer to other supporting documents;

[0086] The samples of the embodiment were analyzed by high performance gas chromatography-mass spectrometry and nuclear magnetic hydrogen spectrum. The structures of the samples were consistent with the structural characteristics of the target product. The patterns of some samples are shown in the attached Figures 2 to 7 .

[0087] The samples of the embodiment and the reference substance were respectively tested by high-efficiency gas chromatograph, and the purity and total impurity of the samples were measured. The results are shown in Table 1, and the gas chromatogram of sample 1 is shown in the attached figure. Figure 8 .

[0088] The yield of each embodiment and control example was calculated according to formula 1. The results are shown in Table 1.

[0089] Formula 1: Yield (%) = actual weight of the sample obtained (g) / theoretical amount calculated based on the amount of methanesulfonyl chloride used (g) × 100%.

[0090] Table 1: Summary of total yield, purity and impurity test results of samples and reference substances

[0091] Sample No. Yield (%) Purity of target product (%) Total impurities (%) Sample 1 98.3 99.96 0.03 Sample 2 98.2 99.97 0.02 Sample 3 98.3 99.90 0.08 Sample 4 98.8 99.93 0.06 Sample 5 98.5 99.73 0.15 Sample 6 98.7 99.81 0.09 Comparative Example 1 90.1 97.62 2.35 Comparative Example 2 91.3 96.37 3.55

[0092] As shown in Table 1, the yields of various embodiments of the present invention can reach over 98.2%, with the highest reaching 98.8%. The purity of the target product of the present invention can reach over 99.9%, with methyl methanesulfonate achieving the highest purity, reaching 99.97%. Furthermore, the moisture content of the product obtained by the present invention is very low, with the minimum moisture content in the product being controlled at 42 mg / kg.

[0093] In Comparative Example 1, the reaction temperature was controlled at 60° C. Although the overall reaction time was very short, only 5 min, the yield of the obtained reference product was low and the purity was also reduced, indicating that the reaction temperature was too high, which would aggravate the side reactions during the reaction.

[0094] Comparative Example 2 employed a synthesis route using an acid-binding agent and a catalyst. The molar amount of the acid-binding agent used was twice that of methanesulfonyl chloride, and tetrabutylammonium bromide was also added as a phase transfer catalyst, resulting in high raw material costs. The reaction required heating and an extended reaction time of up to 6 hours, resulting in a lower yield and purity than the control product prepared in the present invention.

Claims

1. A method for preparing a mesylate product, characterized in that: In a dichloromethane system, the reaction temperature is controlled to be no higher than 40°C and the reaction rate is controlled to react a mixed solution of methanesulfonyl chloride and methanesulfonic anhydride with sodium alkoxide. After the reaction is completed, the reaction solution is cooled to room temperature, filtered, dried, and rotary evaporated to remove the solvent. After rectification, a mesylate product is obtained; The specific operation of controlling the reaction temperature to not higher than 40°C is as follows: placing the reaction system in an ice-water bath to control the reaction temperature at 30°C or 40°C; The molar ratio of methanesulfonyl chloride to sodium alkoxide is 1:1, and the sodium alkoxide is sodium methoxide or sodium methoxide methanol solution; When the molar amount of methanesulfonyl chloride used in the reaction is 0.052 mol, the molar amount of methanesulfonic anhydride is 0.000052 mol or 0.00010 mol; The reaction time of the reaction is 20 min or 30 min.

2. The method for preparing a mesylate product according to claim 1, wherein The specific operation of controlling the reaction rate is as follows: adding a mixed solution of methanesulfonyl chloride and methanesulfonic anhydride or sodium alkoxide to the dichloromethane system in a dropwise manner.

3. The method for preparing a mesylate product according to claim 2, wherein: Stirring is also required during the dropwise addition process.

4. The method for preparing a mesylate product according to claim 1, wherein The specific operation of the distillation is as follows: a glass fiber packing column with a length of 25 cm or 30 cm is used as a distillation device, a diaphragm pump is used to evacuate, and the reaction solution is heated to 95°C to 120°C for distillation to obtain the product.

5. The method for preparing a mesylate product according to claim 1, wherein The preparation process of the mixed solution of methanesulfonyl chloride and methanesulfonic anhydride is as follows: methanesulfonic acid is added to a reaction flask, stirred, heated to 100°C or 105°C, thionyl chloride is added dropwise, and after the reaction is completed, excess thionyl chloride is removed by vacuum distillation. The reaction solution is concentrated, vacuum distilled, and heated for rectification. The fraction at 70°C is collected to obtain methanesulfonyl chloride, and the fraction at 120°C to 150°C is collected to obtain methanesulfonic anhydride. The methanesulfonyl chloride and methanesulfonic anhydride are dissolved in dichloromethane.

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