Cyclic sulfate compound, and preparation method therefor and use thereof

Abstract

A cyclic sulfate compound, and a preparation method therefor and the use thereof. The preparation method comprises the following steps: (1) dissolving mannitol and an organic alkali in an organic solvent, introducing a sulfuryl fluoride gas at -5 to 20°C, and continuing to react same for a certain time after the introduction is finished; and (2) adding phosphorus oxyfluoride to the solution, which has been subjected to the reaction in step (1), at -15 to 0°C, and continuing to react same for a certain time after the addition is finished, so as to obtain a cyclic sulfate compound represented by structural formula I. The preparation method provided in the present application can be used to simply and easily prepare the cyclic sulfate compound, as represented by structural formula I, having a high purity, low moisture and low acid value, with a high yield at a low cost, and the substance can satisfy the usage requirements of additives of a lithium-ion battery.

Description

Cyclic sulfate compounds and their preparation method and application Technical Field

[0001] The present application belongs to the technical field of compound synthesis, and in particular relates to a cyclic sulfate compound and a preparation method and application thereof. Background Art

[0002] Electrolyte additives are a crucial component of lithium-ion batteries. High-quality electrolyte additives play a positive electrochemical role in lithium secondary batteries, improving their kinetics and significantly enhancing their overall performance. Cyclic sulfate compounds, as a novel lithium battery electrolyte additive, possess the aforementioned excellent properties and are therefore being extensively researched and developed.

[0003] Most of the currently reported methods for preparing cyclic sulfate compounds are to first react an alcohol compound with thionyl chloride to obtain the corresponding cyclic sulfite, which is then further oxidized to obtain the cyclic sulfate. A common problem with this method is that the use of thionyl chloride during the reaction makes it difficult to remove the introduced chloride ions, which affects the product quality. In addition, the oxidation step has high operating and material costs. For example, Chinese patent document 202011587546.3 discloses a method for preparing cyclic sulfite by reacting pentaerythritol with thionyl chloride, and then further using ruthenium trichloride and sodium hypochlorite as oxidants to prepare the cyclic sulfite. This method is cumbersome to operate, the oxidizing reagent is expensive, and the manufacturing cost is high.

[0004] Therefore, a simple, easy and low-cost method for preparing cyclic sulfate compounds is provided, which is a technical problem that needs to be solved urgently by those skilled in the art.

[0005] Application Contents

[0006] The purpose of this application is to provide a method for preparing a cyclic sulfate ester compound, which can be simply, easily and at low cost to produce a cyclic sulfate ester compound shown in structural formula 1 with high yield, high purity, low moisture content and low acid value, and the substance can meet the use requirements of an additive for lithium-ion batteries.

[0007] Another object of the present application is to provide a cyclic sulfate ester compound that can improve the high-temperature storage and high-temperature cycle performance of lithium-ion batteries.

[0008] Another object of the present application is to provide an application of a cyclic sulfate ester compound, which, when used as an additive for lithium-ion batteries, can improve the high-temperature storage and high-temperature cycle performance of lithium-ion batteries.

[0009] To achieve the above objectives, the present application provides a method for preparing a cyclic sulfate ester compound, comprising the following steps:

[0010] (1) dissolving mannitol and an organic base in an organic solvent, introducing sulfuryl fluoride gas at -5 to 20° C., and continuing the reaction for a certain period of time after the introduction is completed;

[0011] (2) adding phosphorus oxytrifluoride to the solution after the reaction in step (1) at -15 to 0° C., and continuing the reaction for a certain period of time after the addition is completed to obtain a cyclic sulfate compound shown in structural formula 1;

[0012] Compared with the prior art, the preparation method of the cyclic sulfate ester compound of the present application uses mannitol, sulfuryl fluoride, and phosphorus oxytrifluoride as preparation raw materials, and the raw materials are easily available and low in cost. At the same time, no further oxidation operation using an oxidant is required. Therefore, the preparation method of the present application is simple and easy to implement, low in cost, and suitable for large-scale industrial production. Moreover, the preparation method of the present application has a high yield, and the prepared cyclic sulfate ester compound has high purity, low moisture content, and low acid value, which can meet the use requirements of additives for lithium-ion batteries.

[0013] Preferably, the organic base of the present application is at least one selected from triethylamine, diethylamine and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU).

[0014] Preferably, the organic solvent of the present application is at least one selected from ethylene glycol dimethyl ether, acetonitrile and acetone.

[0015] Preferably, in step (1) of the present application, the time for introducing sulfuryl fluoride gas is 2 to 8 hours, and the reaction is continued for 1 to 4 hours after the introduction is completed.

[0016] Preferably, the addition time of phosphorus oxyfluoride in step (2) of the present application is 2 to 6 hours, and the reaction is continued for 2 to 8 hours after the addition is completed.

[0017] Preferably, the introduction rate of sulfuryl fluoride gas in the present application is 30 to 90 g / h. Specifically, the introduction rate of sulfuryl fluoride needs to be adjusted and controlled according to the reaction temperature and reactor pressure to improve the reaction conversion rate and reduce the production of by-products; therefore, in step (1), the reaction temperature is controlled at -5 to 20°C, the pressure is controlled at 0 to 10 bar, and the introduction rate of sulfuryl fluoride is preferably 30 to 90 g / h.

[0018] Preferably, the phosphorus oxyfluoride of the present application is added at a rate of 20 to 80 g / h. Specifically, the reaction activity in step (2) is higher, and thus the reaction temperature is lower. Controlling the temperature between -15 and 0°C can achieve a better conversion rate, which is beneficial for the subsequent purification and separation of the product. Therefore, the reaction temperature in step (2) is controlled between -15 and 0°C, the pressure is controlled between 0 and 10 bar, and the phosphorus oxyfluoride addition rate is preferably 20 to 80 g / h.

[0019] Preferably, the molar ratio of mannitol, sulfuryl fluoride, organic base and phosphorus oxyfluoride in the present application is 1:2:7:1. Mannitol and sulfuryl fluoride react in a molar ratio of 1:2 and produce four parts of HF. Two parts of HF are also produced in the reaction of step (2). Therefore, at least six parts of organic base are required to remove HF. Adding one more part of organic base can fully remove the HF produced by the reaction. Therefore, the molar ratio of mannitol, sulfuryl fluoride and organic base is preferably 1:2:7.

[0020] Preferably, the organic base hydrogen fluoride compound produced by the reaction of step (1) and step (2) of the present application can be directly purified and used as a fluorination reagent.

[0021] Preferably, steps (1) and (2) of the present application are both carried out in a high-pressure reactor.

[0022] To achieve the above objectives, the present application also provides a cyclic sulfate compound, which is prepared by the above-mentioned preparation method of the cyclic sulfate compound.

[0023] Compared with the prior art, the cyclic sulfate compounds of the present application have high purity, low moisture content, and low acid value, and the substances can improve the high-temperature storage and high-temperature cycle performance of lithium-ion batteries.

[0024] To achieve the above objectives, the present application also provides an application of a cyclic sulfate ester compound, wherein the cyclic sulfate ester compound prepared by the above-mentioned preparation method of the cyclic sulfate ester compound is used as an additive for lithium-ion batteries.

[0025] Compared with the prior art, the cyclic sulfate compounds of the present application have high purity, low moisture content, and low acid value, which can meet the requirements for use as electrolyte additives. When used as additives for lithium-ion batteries, they can improve the high-temperature storage and high-temperature cycle performance of lithium-ion batteries. DETAILED DESCRIPTION

[0026] The preparation route and mechanism analysis of the preparation method of the cyclic sulfate ester compounds of the present application are described below:

[0027] (1) dissolving mannitol and an organic base in an organic solvent, introducing sulfuryl fluoride gas at -5 to 20° C., and continuing the reaction for a certain period of time after the introduction is completed to obtain a substance of structural formula 2;

[0028] Sulfuryl fluoride is introduced into mannitol to carry out a cyclization reaction. This reaction generates heat. A reaction temperature above 20°C easily leads to product decomposition, low selectivity, and an increase in by-products. Therefore, the reaction temperature needs to be lowered. However, a temperature below -5°C will lead to too low reaction activity, requiring an increase in reaction time, resulting in too low production efficiency. Therefore, the reaction temperature is controlled at -5 to 20°C.

[0029] Specifically, the two fluorine atoms on sulfuryl fluoride have super strong electron-withdrawing ability, which puts the sulfur atom in an electron-deficient state, thereby making the lone pair of electrons on the mannitol hydroxyl group easily undergo nucleophilic substitution reaction with the sulfur atom. Due to the presence of steric hindrance, sulfuryl fluoride will preferentially undergo nucleophilic substitution reaction with the hydroxyl group with less steric hindrance, and the selectivity performance reaches more than 90%. The organic base plays the role of removing hydrogen fluoride, making the reaction irreversible. When the first step of the nucleophilic substitution reaction is successfully carried out, due to the presence of steric hindrance, the fluorosulfonate tends to undergo a cyclization reaction with the hydroxyl group at the adjacent position to form a cyclic sulfate, and finally to produce a substance of structural formula 2. The overall conversion rate of this step can reach more than 80%.

[0030] (2) adding phosphorus oxytrifluoride to the solution after the reaction in step (1) at -15 to 0° C., and continuing the reaction for a certain period of time after the addition is completed to obtain a cyclic sulfate compound shown in structural formula 1;

[0031] Phosphorus oxyfluoride is continuously introduced into the cyclization reaction 1 to carry out the cyclization reaction 2. The cyclization reaction 2 is more intense than the cyclization reaction 1, releases more heat, and has higher reaction activity. Therefore, the reaction temperature needs to be controlled between -15 and 0°C. Otherwise, a reaction temperature above 0°C will easily lead to product decomposition, low selectivity, and an increase in by-products. A temperature below -15°C will result in too low reaction activity, too long a reaction time, and low production efficiency.

[0032] Specifically, the activity of phosphorus oxytrifluoride is far greater than that of sulfuryl fluoride. Hydroxyl groups can quickly undergo a cyclosubstitution reaction with phosphorus oxytrifluoride, and the conversion rate of this reaction is as high as 99%. Therefore, if mannitol is allowed to react with phosphorus oxytrifluoride first, all the hydroxyl groups on mannitol will react with phosphorus oxytrifluoride to form a ring. Therefore, sulfuryl fluoride needs to react with mannitol first.

[0033] In order to better illustrate the purpose, technical solutions and beneficial effects of this application, the application will be further described below in conjunction with specific embodiments. It should be noted that the following implementation method is a further explanation of this application and should not be regarded as a limitation of this application.

[0034] Example 1

[0035] This embodiment provides a method for preparing a cyclic sulfate compound, comprising the following steps:

[0036] (1) 182.1 g (1.0 mol) of mannitol, 1416.0 g of acetonitrile, and 708.4 g (7.0 mol) of triethylamine were added to a dry 5 L autoclave. A -30°C freezing liquid was introduced into the autoclave refrigeration coil and the temperature was controlled to -5°C with stirring. 204.2 g (2.0 mol) of sulfuryl fluoride was slowly introduced over 4 h. During this period, the temperature of the autoclave was controlled at -5 to 20°C. After the introduction was completed, the reaction was continued with stirring for 2 h. The reaction solution was sampled and the conversion rate of the second structural formula was 85.3% by TLC detection.

[0037] (2) The -30°C freezing liquid was continuously introduced into the freezing coil of the 5L autoclave in step (1) and the temperature was controlled to -15°C by stirring. 104.0g (1.0mol) of phosphorus oxytrifluoride was slowly added to the 5L autoclave in step (1) over 2 hours, during which the temperature of the autoclave was controlled at -15 to 0°C. After the addition was completed, the reaction was continued with stirring for 3 hours. The reaction solution was sampled and tested by TLC. The conversion rate of the structural formula was 77.4%. The product was filtered, concentrated and crystallized, and dried under vacuum at 50°C to obtain 260.2g of the target product with a yield of 70.3%, a liquid chromatography purity of 99%, an acid value of 21ppm, and a water content of 65ppm. The obtained structural formula was analyzed by nuclear magnetic resonance. Its nuclear magnetic resonance hydrogen spectrum: 1H NMR (56MHz,) δ3.54, 4.76, 4.58; carbon spectrum: 13C NMR (56MHz,) δ68.9, 76.7, 85.9.

[0038] Example 2

[0039] This embodiment provides a method for preparing a cyclic sulfate compound, comprising the following steps:

[0040] (1) 182.1 g (1.0 mol) of mannitol, 1416.0 g of ethylene glycol dimethyl ether, and 708.4 g (7.0 mol) of triethylamine were added to a dry 5 L autoclave. A -30°C freezing liquid was introduced into the autoclave refrigeration coil and the temperature was controlled to -5°C with stirring. 204.2 g (2.0 mol) of sulfuryl fluoride was slowly introduced within 5 h. During this period, the temperature of the autoclave was controlled at -5 to 20°C. After the introduction was completed, the reaction was continued with stirring for 1 h. The reaction solution was sampled and the conversion rate of the second structural formula was 84.2% by TLC.

[0041] (2) The -30°C freezing liquid was continuously introduced into the freezing coil of the 5L autoclave in step (1) and the temperature was controlled to -15°C by stirring. 104.0g (1.0mol) of phosphorus oxyfluoride was slowly added to the 5L autoclave in step (1) over 2.5h. During this period, the temperature of the autoclave was controlled at -15 to 0°C. After the addition was completed, the reaction was continued with stirring for 4h. The reaction solution was sampled and tested by TLC. The conversion rate of the structural formula 1 was 75.3%. The product was filtered, concentrated and crystallized, and dried under vacuum at 50°C to obtain 257.3g of the target product. The yield was 69.5%, the liquid chromatography purity was 99%, the acid value was 25ppm, and the water content was 75ppm. The obtained structural formula 1 was analyzed by nuclear magnetic resonance. Its nuclear magnetic resonance hydrogen spectrum: 1H NMR (56MHz,) δ3.53, 4.74, 4.59; carbon spectrum: 13C NMR (56MHz,) δ68.8, 76.5, 85.7.

[0042] Example 3

[0043] This embodiment provides a method for preparing a cyclic sulfate compound, comprising the following steps:

[0044] (1) 182.1 g (1.0 mol) of mannitol, 1416.0 g of acetonitrile, and 1065.7 g (7.0 mol) of DBU were added to a dry 5 L autoclave. A -30°C freezing liquid was introduced into the autoclave refrigeration coil and the temperature was controlled to -5°C with stirring. 204.2 g (2.0 mol) of sulfuryl fluoride was slowly introduced over 4 h. During this period, the temperature of the autoclave was controlled at -5 to 20°C. After the introduction was completed, the reaction was continued with stirring for 1.5 h. The reaction solution was sampled and the conversion rate of the second structural formula was 88.2% by TLC.

[0045] (2) The -30°C freezing liquid was continuously introduced into the freezing coil of the 5L autoclave in step (1) and the temperature was controlled to -15°C by stirring. 104.0g (1.0mol) of phosphorus oxytrifluoride was slowly added to the 5L autoclave in step (1) over 3.5h. During this period, the temperature of the autoclave was controlled at -15 to 0°C. After the addition was completed, the reaction was continued with stirring for 4h. The reaction solution was sampled and tested by TLC. The conversion rate of the structural formula 1 was 79.3%. The product was filtered, concentrated and crystallized, and dried under vacuum at 50°C to obtain 277.6g of the target product. The yield was 72.3%, the liquid chromatography purity was 99%, the acid value was 16ppm, and the water content was 48ppm. The obtained structural formula 1 was analyzed by nuclear magnetic resonance. Its nuclear magnetic resonance hydrogen spectrum: 1H NMR (56MHz,) δ3.57, 4.77, 4.62; carbon spectrum: 13C NMR (56MHz,) δ68.6, 76.3, 85.5.

[0046] Example 4

[0047] This embodiment provides a method for preparing a cyclic sulfate compound, comprising the following steps:

[0048] (1) 182.1 g (1.0 mol) of mannitol, 1416.0 g of acetone, and 1065.7 g (7.0 mol) of DBU were added to a dry 5 L autoclave. A -30°C freezing liquid was introduced into the autoclave refrigeration coil and the temperature was controlled to -5°C with stirring. 204.2 g (2.0 mol) of sulfuryl fluoride was slowly introduced over 4 h. During this period, the temperature of the autoclave was controlled at -5 to 20°C. After the introduction was completed, the reaction was continued with stirring for 1.5 h. The reaction solution was sampled and the conversion rate of the second structural formula was 82.1% by TLC.

[0049] (2) The -30°C freezing liquid was continuously introduced into the freezing coil of the 5L autoclave in step (1) and the temperature was controlled to -15°C by stirring. 104.0g (1.0mol) of phosphorus oxyfluoride was slowly added to the 5L autoclave in step (1) over 2.5h. During this period, the temperature of the autoclave was controlled at -15 to 0°C. After the addition was completed, the reaction was continued with stirring for 4h. The reaction solution was sampled and tested by TLC. The conversion rate of the reaction solution was 73.3%. The product was filtered, concentrated and crystallized, and dried under vacuum at 50°C to obtain 241.7g of the target product. The yield was 65.3%, the liquid chromatography purity was 99%, the acid value was 56ppm, and the water content was 71ppm. The obtained structural formula 1 was analyzed by nuclear magnetic resonance. Its nuclear magnetic resonance hydrogen spectrum: 1H NMR (56MHz,) δ3.56, 4.76, 4.61; carbon spectrum: 13C NMR (56MHz,) δ68.5, 76.2, 85.4.

[0050] Example 5

[0051] This embodiment provides a method for preparing a cyclic sulfate compound, comprising the following steps:

[0052] (1) 182.1 g (1.0 mol) of mannitol, 1416.0 g of acetonitrile, and 512.0 g (7.0 mol) of diethylamine were added to a dry 5 L autoclave. A -30°C freezing liquid was introduced into the autoclave refrigeration coil and the temperature was controlled to -5°C with stirring. 204.2 g (2.0 mol) of sulfuryl fluoride was slowly introduced over 3.5 h. During this period, the temperature of the autoclave was controlled at -5 to 20°C. After the introduction was completed, the reaction was continued with stirring for 2 h. The reaction solution was sampled and the conversion rate of the second structural formula was 80.7% by TLC.

[0053] (2) The -30°C freezing liquid was continuously introduced into the freezing coil of the 5L autoclave in step (1) and the temperature was controlled to -15°C by stirring. 104.0g (1.0mol) of phosphorus oxytrifluoride was slowly added to the 5L autoclave in step (1) over 2 hours. During this period, the temperature of the autoclave was controlled at -15 to 0°C. After the addition was completed, the reaction was continued with stirring for 3 hours. The reaction solution was sampled and tested by TLC. The conversion rate of the structural formula 1 was 70.2%. The product was filtered, concentrated and crystallized, and dried under vacuum at 50°C to obtain 222.9g of the target product. The yield was 60.2%, the liquid chromatography purity was 99%, the acid value was 33ppm, and the water content was 49ppm. The obtained structural formula 1 was analyzed by nuclear magnetic resonance. Its nuclear magnetic resonance hydrogen spectrum: 1H NMR (56MHz,) δ 3.53, 4.75, 4.57; carbon spectrum: 13C NMR (56MHz,) δ 68.8, 76.8, 85.7.

[0054] In summary, the preparation method of the cyclic sulfate ester compound of the present application uses mannitol and sulfuryl fluoride to react under the catalysis of an organic base to produce structural formula 2, and then structural formula 2 is reacted with phosphorus oxytrifluoride under the catalysis of an organic base to obtain a cyclic sulfate ester compound represented by structural formula 1 with a yield of more than 60%, high purity, low moisture content, and low acid value. Nuclear magnetic resonance analysis shows that the compound has an effective nuclear magnetic resonance hydrogen spectrum and carbon spectrum.

[0055] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, it is not limited to those listed in the embodiments. Those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for preparing a cyclic sulfate ester compound, characterized in that the steps include: (1) dissolving mannitol and an organic base in an organic solvent, introducing sulfuryl fluoride gas at -5 to 20° C., and continuing the reaction for a certain period of time after the introduction is completed; (2) adding phosphorus oxyfluoride to the solution after the reaction in step (1) at -15 to 0° C., and continuing the reaction for a certain period of time after the addition is completed to obtain a cyclic sulfate compound represented by structural formula 1; 2. The method for preparing a cyclic sulfate ester compound according to claim 1, wherein: The organic base is selected from at least one of triethylamine, diethylamine and DBU.

3. The method for preparing a cyclic sulfate ester compound according to claim 1, wherein The organic solvent is selected from at least one of ethylene glycol dimethyl ether, acetonitrile and acetone.

4. The method for preparing a cyclic sulfate ester compound according to claim 1, wherein The sulfuryl fluoride gas is introduced into the reaction mixture for 2 to 8 hours, and the reaction is continued for 1 to 4 hours after the introduction is completed.

5. The method for preparing a cyclic sulfate ester compound according to claim 1, wherein The phosphorus oxyfluoride in step (2) is added for 2 to 6 hours, and the reaction is continued for 2 to 8 hours after the addition is completed.

6. The method for preparing a cyclic sulfate ester compound according to claim 1, wherein: The introduction rate of the sulfuryl fluoride gas is 30 to 90 g / h.

7. The method for preparing a cyclic sulfate ester compound according to claim 1, characterized in that: The adding speed of the phosphorus oxyfluoride is 20 to 80 g / h.

8. The method for preparing a cyclic sulfate ester compound according to claim 1, wherein: The molar ratios of the mannitol, the sulfuryl fluoride, the organic base and the phosphorus oxytrifluoride are 1:2:7:1 respectively.

9. A cyclic sulfate compound, characterized in that: The cyclic sulfate ester compound is prepared by the preparation method of any one of claims 1 to 8.

10. An application of a cyclic sulfate ester compound, characterized in that: The cyclic sulfate ester compound prepared by the preparation method of the cyclic sulfate ester compound according to any one of claims 1 to 8 is used as an additive for lithium ion batteries.

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