Preparation method and application of low-chroma ethylene sulfate

Abstract

The invention discloses a preparation method of low-chroma ethylene sulfate. The ethylene sulfate obtained by the method is high in purity and low in chroma. The purification method provided by the invention is simple in steps, and the obtained ethylene sulfate is low in chromaticity. The ethylene sulfate prepared by the method can be directly used for preparing an electrolyte containing the ethylene sulfate, and secondary treatment is not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of vinyl sulfate, and in particular relates to low-chroma vinyl sulfate. Background Art

[0002] As a new type of electrolyte additive, vinyl sulfate can inhibit the solvent decomposition reaction on the negative electrode and effectively reduce the impedance of the battery; it can inhibit the reduction of battery capacity and the generation of gas under high and low temperature conditions, which is good for the high and low temperature electrochemical performance of the battery; and vinyl sulfate can greatly extend the rechargeable life of the battery. Vinyl sulfate can also be used as a hydroxyethylation reagent in organic synthesis to synthesize drug intermediates, and can also be used to synthesize certain heterocyclic compounds for gelatin hardening, antihypertensive drugs, and raw materials for new dual surfactants. It has broad market value and application prospects.

[0003] The currently disclosed methods for preparing vinyl sulfate mainly include direct acylation, substitution, addition, oxidation and dioxane synthesis. However, actual industrial production is mainly based on oxidation, which has many operable routes, mainly due to the different selection of catalysts and oxidants. With the continuous deepening of lithium battery applications, the demand for the synthesis of vinyl sulfate is also increasing, and higher requirements are also placed on the quality of vinyl sulfate. In order to obtain higher quality finished vinyl sulfate, it is necessary to refine and purify the crude vinyl sulfate. In view of the incomplete reaction of the oxidation method, the residue of cyclic vinyl sulfite increases the difficulty of purifying vinyl sulfate. Chinese patent CN101456857B reports a method for preparing high-purity cyclic sulfate, by adding potassium permanganate solid to the cyclic sulfate, and then reducing the generated manganese dioxide and excess potassium permanganate with a reducing agent such as sodium bisulfite, and finally the organic layer is washed with water, alkali washed, washed with water, dried, desolventized and the like to obtain a high-purity cyclic sulfate. This method has complicated steps and introduces new substances, increasing the risk of introducing other impurities. It cannot be used directly as an electrolyte additive for lithium-ion batteries. Summary of the invention

[0004] In order to improve the above technical problems, the present invention provides a method for preparing vinyl sulfate. The method has simple purification steps, and the obtained vinyl sulfate has high purity and low chroma, and can be directly used as a lithium ion battery electrolyte additive.

[0005] The purpose of the present invention is achieved by the following methods:

[0006] The present invention provides a method for preparing low-chroma vinyl sulfate, comprising the following steps:

[0007] Step 1, add ethylene dichloride, vinyl sulfite and TS-1 into a reactor and stir evenly;

[0008] Step 2, adding hydrogen peroxide solution dropwise to the above reactor at room temperature to obtain a crude vinyl sulfate solution, and performing low-temperature crystallization, wherein the low-temperature crystallization temperature is controlled at -20 to 0 degrees to obtain a crude vinyl sulfate solution;

[0009] Step 3, dissolving the crude vinyl sulfate product in step 2 in a halogenated hydrocarbon solvent to prepare a solution containing vinyl sulfate; introducing ozone to react;

[0010] Step 4, washing, neutralizing, washing, drying, and distilling under reduced pressure the solution in step 3 to remove the solvent to obtain a finished product of vinyl sulfate.

[0011] Furthermore, the mass ratio of ethylene dichloride, vinyl sulfite and TS-1 in step 1 is 3:1: (1% to 10%), and the 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 halogenated hydrocarbon solvent in step 3 includes one or more of dichloromethane, chloroform, tetrachloromethane, dichloroethane, dichloropropane, and trichloropropane.

[0014] Furthermore, the ozone flow rate in step 3 is 10-15 mg / min, and the reaction time is 10-20 min.

[0015] Furthermore, the finished vinyl sulfate product prepared by the above method is used as an additive for lithium-ion battery electrolyte.

[0016] Beneficial effects of the present invention:

[0017] The present invention provides a method for preparing low-chroma vinyl sulfate, wherein the vinyl sulfate obtained by the method has high purity and low chroma. The method provided by the present invention has simple purification steps, and the obtained vinyl sulfate can be directly used as an electrolyte additive for lithium ion batteries. DETAILED DESCRIPTION

[0018] 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.

[0019] Unless otherwise specified, the raw materials and reagents used in the following examples are commercially available or can be prepared by known methods.

[0020] Example 1

[0021] Add 100 grams of vinyl sulfite, 300 grams of ethylene dichloride and 2.0 grams of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 30 to 40 degrees, then add 140 grams of hydrogen peroxide solution, and continue to stir and react in a water bath at 30 to 40 degrees for 4 hours after the addition is complete. Let the liquid stand for separation, take the organic layer, and place it at -20 degrees for low-temperature crystallization. Filter to obtain crude vinyl sulfate. Dissolve the crude vinyl sulfate in ethylene dichloride, and then pass a certain amount of ozone (ozone flow rate 12 mg / min) into the solution, and stop passing it after 10 minutes. Finally, the organic layer is washed with water, neutralized, washed with water, dried, and distilled under reduced pressure to remove the solvent. Finally, the finished vinyl sulfate can be used as an additive for lithium-ion battery electrolyte. Test the purity, moisture, acid value, and chromaticity of the finished vinyl sulfate.

[0022] Example 2

[0023] Add 100 grams of vinyl sulfite, 300 grams of ethylene dichloride and 2.0 grams of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 30 to 40 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, take the organic layer, and place it at -20 degrees for low-temperature crystallization. Filter to obtain crude vinyl sulfate. Dissolve the crude vinyl sulfate in ethylene dichloride, and then pass a certain amount of ozone (ozone flow rate 12 mg / min) into the solution, and stop passing it after 20 minutes. Finally, the organic layer is washed with water, neutralized, washed with water, dried, and distilled under reduced pressure to remove the solvent, and finally the finished vinyl sulfate is obtained. Test the purity, moisture, acid value, and chromaticity of the finished vinyl sulfate.

[0024] Example 3

[0025] Add 100 grams of vinyl sulfite, 300 grams of ethylene dichloride and 2.0 grams of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 30 to 40 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, take the organic layer, and place it at -20 degrees for low-temperature crystallization. Filter to obtain crude vinyl sulfate. Dissolve the crude vinyl sulfate in ethylene dichloride, and then pass a certain amount of ozone (ozone flow rate 15 mg / min) into the solution, and stop passing it after 10 minutes. Finally, the organic layer is washed with water, neutralized, washed with water, dried, and distilled under reduced pressure to remove the solvent. Finally, the finished vinyl sulfate can be used as an additive for lithium-ion battery electrolyte. Test the purity, moisture, acid value, and chromaticity of the finished vinyl sulfate.

[0026] Comparative Example 1

[0027] Add 100 grams of vinyl sulfite, 300 grams of ethylene dichloride and 2.0 grams of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 30 to 40 degrees, then add 140 grams of hydrogen peroxide solution, and continue to stir and react in a water bath at 30 to 40 degrees for 4 hours after the addition is complete. Let the liquid stand for separation, take the organic layer, and place it at -20 degrees for low-temperature crystallization. Filter to obtain crude vinyl sulfate. Dissolve the crude vinyl sulfate in ethylene dichloride, and add an appropriate amount of potassium permanganate solid in batches until it is slightly excessive. Then add an appropriate amount of sodium sulfite for reduction reaction to make the final system colorless. The organic layer is washed with water, neutralized, washed with water, dried, and distilled under reduced pressure to remove the solvent, and finally the finished vinyl sulfate is obtained. Test the purity, moisture, acid value, and chromaticity of the finished vinyl sulfate.

[0028] Comparative Example 2

[0029] Add 100 g of vinyl sulfite, 300 g of ethylene dichloride and 2.0 g of TS-1 to a three-necked flask, stir evenly with magnetic force in a water bath at 30-40 degrees, then drop 140 g 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, take the organic layer, and place it at -20 degrees for low-temperature crystallization. Filter to obtain crude vinyl sulfate. Dissolve the crude vinyl sulfate in ethylene dichloride, then wash, neutralize, wash, dry, and distill under reduced pressure to remove the solvent. Finally, the finished vinyl sulfate can be used as an electrolyte additive for lithium-ion batteries. Test the purity, moisture, acid value, and chromaticity of the finished vinyl sulfate.

[0030] The above test results are shown below.

[0031] purity / % Moisture / ppm Acid value / ppm Chroma / ppm Example 1 99.88 46.74 32.92 6.14 Example 2 99.86 43.12 29.19 4.81 Example 3 99.92 36.43 23.8 3.68 Comparative Example 1 99.61 55.36 44.50 14.78 Comparative Example 2 98.74 59.10 53.73 24.31

[0032] 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. 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 patent application of the present invention should fall within the protection scope of the claims of the present invention. The descriptions of 30 to 40 degrees, -20 to 0 degrees, 1% to 10%, 10 to 20 minutes, etc. all include the values ​​at both ends.

[0033] 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 low-color vinyl sulfate, characterized in that: The following steps are involved: Step 1, add ethylene dichloride, vinyl sulfite and TS-1 into a reactor and stir evenly; Step 2, adding a hydrogen peroxide solution dropwise into the reactor at room temperature to obtain a crude liquid vinyl sulfate solution, and crystallizing the solution at a temperature of -20 to 0 degrees to obtain a crude vinyl sulfate product; Step 3, dissolving the crude vinyl sulfate product in step 2 in a halogenated hydrocarbon solvent to prepare a solution containing vinyl sulfate; introducing ozone to react; Step 4, washing, neutralizing, washing, drying, and distilling under reduced pressure the solution prepared in step 3 to remove the solvent to obtain a finished product of vinyl sulfate.

2. The method according to claim 1, characterized in that: The mass ratio of ethylene dichloride, vinyl sulfite and TS-1 is 3:1: (1% to 10%), and the stirring temperature is controlled at 10 to 50 degrees.

3. The method according to claim 1, characterized in that: The mass ratio of the hydrogen peroxide solution to the vinyl sulfite is 5:7, and the temperature during the dropwise addition is controlled at 30 to 40 degrees.

4. The method according to claim 1, characterized in that: The halogenated hydrocarbon solvent includes one or more of dichloromethane, chloroform, tetrachloromethane, dichloroethane, dichloropropane, and trichloropropane.

5. The method according to claim 1, characterized in that: The ozone flow rate is 10-15 mg / min, and the reaction time is 10-20 min.

6. Use of the finished vinyl sulfate product prepared by the method according to any one of claims 1 to 5 as an additive for lithium ion battery electrolyte.