Preparation method of battery-grade liquid ethylene sulfate containing methyl ethyl carbonate

Abstract

The invention relates to the technical field of ethylene sulfate, in particular to a preparation method of battery-grade liquid ethylene sulfate containing ethyl methyl carbonate. The method comprises the following steps: 1, adding methyl ethyl carbonate, ethylene sulfite and TS-1 into a reactor, and uniformly stirring to prepare a mixed solution; step 2, dropwise adding a hydrogen peroxide solution into the mixed solution prepared in the step 1 at normal temperature to obtain a liquid ethylene sulfate crude product solution; step 3, layering the liquid ethylene sulfate solution crude product prepared in the step 2, and washing, neutralizing and drying an organic layer to obtain a liquid ethylene sulfate finished product solution; 4, 732 type strong acid cation exchange resin is added into the liquid ethylene sulfate finished product solution prepared in the step 3; and magnetically stirring at normal temperature for a period of time, filtering at normal pressure, neutralizing and drying to obtain a battery-grade liquid ethylene sulfate finished product solution. The liquid ethylene sulfate solution prepared by the method is low in metal ion content, corrosion and damage of metal ions to the internal structure of a battery are reduced, and the cycle life and the service life of the battery are prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of vinyl sulfate, and in particular to a method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate. Background Art

[0002] As an excellent film-forming additive for lithium-ion battery electrolyte, vinyl sulfate can effectively reduce the impedance of the battery and improve the battery's cycle life, rate performance, high temperature performance, low temperature performance, etc. Vinyl sulfate is a white crystal or crystalline powder, which is easy to absorb water and hydrolyze in a humid environment and is thermally unstable. Therefore, the packaging, storage and transportation of vinyl sulfate products have relatively high requirements for the temperature and humidity of the environment.

[0003] The preparation methods of vinyl sulfate reported in existing patents mostly obtain solid vinyl sulfate finished products. However, the dust pollution caused by the packaging of solid vinyl sulfate finished products is not conducive to health and hygiene, and foreign impurities may be introduced on the other hand. The use of liquid vinyl sulfate can solve these problems and is more convenient. Chinese patent CN113683592A reports a preparation method of ethyl methyl carbonate solution containing vinyl sulfate, in which hypochlorite and vinyl sulfite are added to ethyl methyl carbonate solution, and a crude ethyl methyl carbonate solution of vinyl sulfate is obtained under the action of ruthenium trichloride catalyst, and the ethyl methyl carbonate solution containing vinyl sulfate is obtained after washing and drying.

[0004] With the further development of high energy density power batteries, people have put forward more stringent requirements on the quality of electrolytes, so it is necessary to develop battery-grade liquid vinyl sulfate. The content of metal ion impurities in the battery system is one of the main reasons for battery capacity decay, so it is very important to control the content of metal ions in the electrolyte. Summary of the invention

[0005] In order to improve the above technical problems, the present invention provides a method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate, and reduces the metal ion content in the liquid vinyl sulfate by an ion exchange method for preparing battery-grade liquid vinyl sulfate.

[0006] To achieve the above object, the present invention provides the following technical solution: a method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate, comprising the following steps:

[0007] Step 1, adding ethyl methyl carbonate, vinyl sulfite and TS-1 into a reactor, stirring uniformly, and preparing a mixed solution;

[0008] Step 2, adding a hydrogen peroxide solution dropwise to the mixed solution prepared in step 1 at room temperature to obtain a crude liquid vinyl sulfate solution;

[0009] Step 3, separating the crude liquid vinyl sulfate solution prepared in step 2, washing the organic layer with water, neutralizing, and drying to obtain a liquid vinyl sulfate finished solution;

[0010] Step 4, adding 732 type strong acid cation exchange resin to the liquid vinyl sulfate finished solution prepared in step 3; stirring magnetically for a period of time at room temperature, filtering at normal pressure, neutralizing, and drying to obtain a battery-grade liquid vinyl sulfate finished solution.

[0011] Furthermore, the mass ratio of ethyl methyl carbonate, vinyl sulfite and TS-1 in step 1 is 2:1: (1% to 10%), and the stirring temperature is controlled at 10 to 50 degrees.

[0012] Furthermore, the mass ratio of the hydrogen peroxide solution to vinyl sulfite in step 2 is 5:7, the temperature during the dropwise addition is controlled at 30 to 40 degrees, and after the dropwise addition is completed, stirring is continued until no vinyl sulfite is detected in the reaction solution.

[0013] Furthermore, the mass ratio of the 732 type strongly acidic cation exchange resin to ethyl methyl carbonate in step 4 is 1:3, the magnetic stirring speed is 200 r / min to 400 r / min, and the stirring time is 10 to 20 min.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The invention provides a method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate. The method uses an ion exchange method, requires a low temperature, has simple steps, and has a low metal ion content in the prepared liquid vinyl sulfate solution, thereby reducing the corrosion and damage of the metal ions to the internal structure of the battery, and helping to extend the cycle life and service life of the battery. DETAILED DESCRIPTION

[0016] The technical scheme of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only exemplary descriptions and explanations of the present invention and should not be construed as limiting the scope of protection of the present invention. All technologies implemented based on the above content of the present invention are included in the scope that the present invention is intended to protect.

[0017] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0018] Example 1

[0019] Add 200 grams of ethyl methyl carbonate, 100 grams of vinyl sulfite and 2.0 grams of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 10 to 50 degrees, then add 140 grams of hydrogen peroxide solution, and continue stirring and reacting in a water bath at 30 to 40 degrees for 4 hours after the addition is complete. Let the liquid stand for separation, wash the organic phase with water several times, dry the obtained organic phase with anhydrous magnesium sulfite, and then dry it with a molecular sieve to obtain a liquid vinyl sulfate solution. Add 67 grams of 732 type strong acid cation exchange resin to the above liquid vinyl sulfate solution, stir magnetically for 15 minutes at room temperature, and the stirring speed is 300r / min. Then filter, neutralize, and dry to obtain a vinyl sulfate solution. Test the moisture, acid value, chromaticity and metal ion content of liquid vinyl sulfate.

[0020] Comparative Example 1

[0021] Add 200g of ethyl methyl carbonate, 100g of vinyl sulfite and 2.0g of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 10-50 degrees, then drop 140g of hydrogen peroxide solution, and continue stirring and reacting in a water bath at 30-40 degrees for 4 hours after the dropwise addition is complete. Let the liquid stand for separation, wash the organic phase with water several times, dry the obtained organic phase with anhydrous magnesium sulfite, and then dry it with molecular sieves to obtain a liquid vinyl sulfate solution. Test the moisture, acid value, chromaticity and metal ion content of liquid vinyl sulfate.

[0022] The test results are shown in Tables 1 and 2 below.

[0023] Table 1: Water content, acid value, and color parameters of liquid vinyl sulfate in Example 1 and Comparative Example 1

[0024] Moisture / ppm Acid value / ppm Chroma / ppm Example 1 8 12 8.21 Comparative Example 1 10 15 9.16

[0025] Table 2: Metal ion content of liquid vinyl sulfate in Example 1 and Comparative Example 1

[0026]

[0027] By comparing the parameters of Example 1 with Comparative Example 1, it can be seen that the metal ion content of the vinyl sulfate solution obtained by adding 732 type strong acid cation exchange resin to the liquid vinyl sulfate finished solution, magnetically stirring for 15 minutes at room temperature, and stirring at a speed of 300r / min, followed by filter pressing, neutralization, and drying is significantly reduced.

[0028] The above is only a preferred embodiment of the present invention. Those skilled in the art can also make appropriate changes and modifications to the above embodiments. For example, during the reaction of 732 type strong acid cation exchange resin and ethyl methyl carbonate, the magnetic stirring speed can be 200r / min to 400r / min. Therefore, the present invention is not limited to the above specific embodiments. All modifications and changes of the structure described in the scope of the present invention's patent application should fall within the protection scope of the claims of the present invention.

[0029] The above is an explanation of the embodiments of the present invention. However, the present invention is not limited to the above embodiments. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate, comprising the following steps: Step 1, adding ethyl methyl carbonate, vinyl sulfite and TS-1 into a reactor, stirring uniformly, and preparing a mixed solution; Step 2, adding a hydrogen peroxide solution dropwise to the mixed solution prepared in step 1 at room temperature to obtain a crude liquid vinyl sulfate solution; Step 3, separating the crude liquid vinyl sulfate solution prepared in step 2, washing the organic layer with water, neutralizing, and drying to obtain a liquid vinyl sulfate finished solution; Step 4, adding 732 type strong acid cation exchange resin to the liquid vinyl sulfate finished solution prepared in step 3; stirring magnetically for a period of time at room temperature, filtering at normal pressure, neutralizing, and drying to obtain a battery-grade liquid vinyl sulfate finished solution.

2. The method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate according to claim 1, characterized in that: The mass ratio of ethyl methyl carbonate, vinyl sulfite and TS-1 in step 1 is 2:1: (1% to 10%), and the stirring temperature is controlled at 10 to 50 degrees.

3. The method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate according to claim 1, characterized in that: The mass ratio of the hydrogen peroxide solution to vinyl sulfite in step 2 is 5:7, the temperature during the dropwise addition is controlled at 30-40 degrees, and after the dropwise addition is completed, stirring is continued until no vinyl sulfite is detected in the reaction solution.

4. The method for preparing battery-grade liquid vinyl sulfate containing ethyl methyl carbonate according to claim 1, characterized in that: The mass ratio of the 732 type strongly acidic cation exchange resin to ethyl methyl carbonate in step 4 is 1:3, the magnetic stirring speed is 200r / min to 400r / min, and the stirring time is 10 to 20min.

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