阅读说明：本技术 一种含硫酸乙烯酯的碳酸甲乙酯溶液的制备方法 (Preparation method of ethyl methyl carbonate solution containing ethylene sulfate ) 是由 陈群 姜飞 张正洪 孙西船 曹国华 于 2021-08-27 设计创作，主要内容包括：一种含硫酸乙烯酯的碳酸甲乙酯溶液的制备方法,它涉及一种锂离子电池电解液制备方法的改进,具体涉及一种含硫酸乙烯酯的碳酸甲乙酯溶液制备方法的改进。本发明采用的技术方案包括以下步骤：在反应釜中加入亚硫酸乙烯酯、碳酸甲乙酯以及微量的三氯化钌水溶液,低温下搅拌均匀；S2,低温下将次氯酸盐水溶液滴加至上述反应釜,得到硫酸乙烯酯的碳酸甲乙酯粗品溶液；将上述硫酸乙烯酯的碳酸甲乙酯粗品溶液进行多次低温水洗分液；在上述水洗分液后的有机相加入脱水剂干燥,得到碳酸甲乙酯溶液成品。本发明解决了硫酸乙烯酯固体产品出现的包装效率低、储存易结块、使用不方便等问题,能够显著地改善硫酸乙烯酯作为锂离子电池电解液添加剂的使用便利性。(A preparation method of a methyl ethyl carbonate solution containing ethylene sulfate relates to the improvement of a preparation method of a lithium ion battery electrolyte, in particular to the improvement of the preparation method of the methyl ethyl carbonate solution containing the ethylene sulfate. The technical scheme adopted by the invention comprises the following steps: adding ethylene sulfite, methyl ethyl carbonate and a trace amount of ruthenium trichloride aqueous solution into a reaction kettle, and uniformly stirring at low temperature; s2, dropwise adding a hypochlorite aqueous solution into the reaction kettle at low temperature to obtain a methyl ethyl carbonate crude product solution of the ethylene sulfate; carrying out low-temperature water washing and liquid separation on the ethyl methyl carbonate crude product solution of the ethylene sulfate for multiple times; and adding a dehydrating agent into the organic phase subjected to water washing and liquid separation, and drying to obtain a finished product of the methyl ethyl carbonate solution. The invention solves the problems of low packaging efficiency, easy caking during storage, inconvenient use and the like of the solid product of the vinyl sulfate, and can remarkably improve the use convenience of the vinyl sulfate as the electrolyte additive of the lithium ion battery.)

1. A preparation method of a methyl ethyl carbonate solution containing ethylene sulfate is characterized by comprising the following steps: the technical scheme adopted by the method comprises the following steps:

s1: adding ethylene sulfite, methyl ethyl carbonate and a trace amount of ruthenium trichloride aqueous solution into a reaction kettle, and uniformly stirring at low temperature;

s2, dropwise adding a hypochlorite aqueous solution into the reaction kettle at low temperature to obtain a methyl ethyl carbonate crude product solution of the ethylene sulfate;

s3, washing the crude ethyl methyl carbonate solution of the ethylene sulfate with water for multiple times at low temperature for liquid separation;

and S4, adding a dehydrating agent into the organic phase subjected to water washing and liquid separation, and drying to obtain a finished product of the methyl ethyl carbonate solution.

2. The method for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein: the mass ratio of the ethylene sulfite, the methyl ethyl carbonate and the ruthenium trichloride (5% Wt) aqueous solution in the step S1 is 1: (4-10): (0.5% -10%), and the low temperature is controlled to-20-5 ℃.

3. The method for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein: the hypochlorite obtained in the step S2 comprises sodium hypochlorite, calcium hypochlorite and potassium hypochlorite, the effective chlorine content of the aqueous solution is 8-16%, and the amount ratio of the effective chlorine content of the dropwise added aqueous solution to the ethylene sulfite substances is (1-1.2): and 1, controlling the temperature to be-20-5 ℃ in the dropping process, and continuously stirring and reacting until no ethylene sulfite can be detected in the organic phase after the dropping is finished.

4. The method for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein: in each water washing process of the step S3, the mass ratio of the ethyl methyl carbonate solution of the ethylene sulfate to the pure water is 5: (1-4), controlling the temperature in the washing process to be 0-10 ℃, controlling the washing times to be 2-6, and controlling the free acid of the organic phase to be less than 10ppm and the chloride ion to be less than 1ppm after washing.

5. The method for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein: the dehydrating agent in the step S4 comprises anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride and a molecular sieve, the moisture of the solution is reduced to be less than 100ppm by using the anhydrous sodium sulfate, the anhydrous magnesium sulfate or the anhydrous calcium chloride, the moisture of the solution is reduced to be less than 10ppm by using the molecular sieve, and the mass concentration of the finished product of the ethyl methyl carbonate solution of the vinyl sulfate is 8-20%.

6. The process for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein the following technical scheme is adopted: adding 50 g of ethylene sulfite, 300 g of methyl ethyl carbonate and 0.6 g of 5% ruthenium trichloride aqueous solution into a three-neck flask, uniformly stirring magnetons at a low temperature of 0 ℃, then dropwise adding 242 g of 15% effective chlorine content calcium hypochlorite aqueous solution, controlling the temperature of a reaction system to be less than 5 ℃ in the dropwise adding process, and continuously stirring and reacting at a low temperature for 2 hours after the dropwise adding is finished; standing, separating, washing the organic phase with 200 g of pure water for 4 times, controlling the temperature in the washing process to be 2-8 ℃, drying the obtained organic phase with anhydrous sodium sulfite, then drying with a molecular sieve to obtain 327 g of a methyl ethyl carbonate solution of 13.5% by mass of ethylene sulfate, and detecting the water content to be 5ppm and the free acid to be 8 ppm.

7. The process for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein the following technical scheme is adopted: adding 50 g of ethylene sulfite, 250 g of methyl ethyl carbonate and 0.5 g of 5% ruthenium trichloride aqueous solution into a three-neck flask, uniformly stirring magnetons at a low temperature of 0 ℃, then dropwise adding 280 g of 13% effective chlorine content sodium hypochlorite aqueous solution, controlling the temperature of a reaction system to be less than 5 ℃ in the dropwise adding process, and continuously stirring and reacting at a low temperature for 2 hours after the dropwise adding is finished; standing, separating, washing the organic phase with 150 g of pure water for 5 times, controlling the temperature in the washing process to be 2-8 ℃, drying the obtained organic phase with anhydrous magnesium sulfite, then drying with a molecular sieve to obtain 260 g of a 15.4% mass concentration ethyl methyl carbonate solution of ethylene sulfate, and detecting the water content to be 6ppm and the free acid to be 7 ppm.

8. The process for preparing a solution of ethyl methyl carbonate containing vinyl sulfate according to claim 1, wherein the following technical scheme is adopted: adding 50 g of ethylene sulfite, 400 g of methyl ethyl carbonate and 1 g of 5% ruthenium trichloride aqueous solution into a three-neck flask, uniformly stirring magnetons at a low temperature of 0 ℃, dropwise adding 400 g of 9% effective chlorine content potassium hypochlorite aqueous solution, controlling the temperature of a reaction system to be less than 5 ℃ in the dropwise adding process, and continuously stirring and reacting at a low temperature for 2 hours after the dropwise adding is finished; standing, separating, washing the organic phase with 300 g of pure water for 3 times, controlling the temperature in the washing process to be 2-8 ℃, drying the obtained organic phase with anhydrous calcium chloride, then drying with a molecular sieve to obtain 385 g of a 12.3% mass concentration ethyl methyl carbonate solution of ethylene sulfate, and detecting the water content to be 5ppm and the free acid to be 8 ppm.

Technical Field

The invention relates to an improvement of a preparation method of lithium ion battery electrolyte, in particular to an improvement of a preparation method of a methyl ethyl carbonate solution containing ethylene sulfate.

Background

The ethylene sulfate is an additive material of lithium ion battery electrolyte with excellent performance. Because the electronegativity of the central sulfur atom of the vinyl sulfate is stronger, and the reducibility of the vinyl sulfate at the interface of the graphite cathode is stronger than that of the corresponding carbonic ester, a more stable solid electrolyte interface film (SEI film) is preferentially formed at the interface of an electrode in the initial charging stage and is used for preventing lithium ions from reacting with a carbon cathode or other substances in the charging and discharging processes, so that the reduction of the initial capacity of the lithium ion battery is inhibited, the initial discharge capacity is increased, the expansion of the battery after high-temperature placement is reduced, the charging and discharging performance of the battery is improved, the cycle number is increased, and the high-low temperature performance of the battery is improved.

The preparation method of the vinyl sulfate ester reported in the prior literature and the patent is to obtain a finished product of the vinyl sulfate ester solid. Chinese patent CN111825652A reports the preparation of vinyl sulfate by oxidation of vinyl sulfite with calcium hypochlorite in an organic solvent followed by recrystallization.

Chinese patent CN109988145B reports that under the action of palladium chloride complex catalyst, ethylene sulfite is oxidized into ethylene sulfate by oxygen, and then filtered, washed with water, concentrated and crystallized to obtain the final product.

Chinese patent CN112375064A reports that under the action of copper chloride catalyst, tert-butyl peroxide is used to oxidize vinyl sulfite into vinyl sulfate, which is then washed, separated, concentrated and crystallized to obtain the final product.

Chinese patent CN109516971B reports that battery-grade vinyl sulfate is obtained by mixing vinyl sulfite and organic peroxide, adding an initiator for reaction, and then carrying out distillation, suction filtration and recrystallization.

Chinese patent CN111533728B reports that ethylene sulfite and dichloroethane are mixed, sodium hypochlorite solution is dripped to carry out oxidation reaction, and the mixture is stood for liquid separation, dehydrated, recrystallized and dried to obtain the ethylene sulfate. The packing of the solid finished product of the vinyl sulfate is very inconvenient, the accurate weighing and metering consume manpower, the efficiency is very low, and the exposure risk exists, so that the environmental dust pollution is possibly caused, the occupational health and sanitation are not facilitated, and foreign matters are possibly introduced into the packing process. The solid package also has a caking phenomenon during the storage process, which causes inconvenience in use. When a user uses the vinyl sulfate to prepare the electrolyte, the solid feeding is difficult to accurately measure, the operation is inconvenient and the like.

Disclosure of Invention

The invention aims to provide a preparation method of a methyl ethyl carbonate solution containing vinyl sulfate aiming at the defects and the defects of the prior art, which can solve the problems of solid products in the processes of packaging, storage, transportation and use.

In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:

s1: adding ethylene sulfite, methyl ethyl carbonate and a trace amount of ruthenium trichloride aqueous solution into a reaction kettle, and uniformly stirring at low temperature;

s2, dropwise adding a hypochlorite aqueous solution into the reaction kettle at low temperature to obtain a methyl ethyl carbonate crude product solution of the ethylene sulfate;

s3, washing the crude ethyl methyl carbonate solution of the ethylene sulfate with water for multiple times at low temperature for liquid separation;

and S4, adding a dehydrating agent into the organic phase subjected to water washing and liquid separation, and drying to obtain a finished product of the methyl ethyl carbonate solution.

The mass ratio of the ethylene sulfite, the methyl ethyl carbonate and the ruthenium trichloride (5% Wt) aqueous solution in the step S1 is 1: (4-10): (0.5% -10%), and the low temperature is controlled to-20-5 ℃.

The hypochlorite obtained in the step S2 comprises sodium hypochlorite, calcium hypochlorite and potassium hypochlorite, the effective chlorine content of the aqueous solution is 8-16%, and the amount ratio of the effective chlorine content of the dropwise added aqueous solution to the ethylene sulfite substances is (1-1.2): and 1, controlling the temperature to be-20-5 ℃ in the dropping process, and continuously stirring and reacting until no ethylene sulfite can be detected in the organic phase after the dropping is finished.

In each water washing process of the step S3, the mass ratio of the ethyl methyl carbonate solution of the ethylene sulfate to the pure water is 5: (1-4), controlling the temperature in the washing process to be 0-10 ℃, controlling the washing times to be 2-6, and controlling the free acid of the organic phase to be less than 10ppm and the chloride ion to be less than 1ppm after washing.

The dehydrating agent in the step S4 comprises anhydrous sodium sulfate, anhydrous magnesium sulfate, anhydrous calcium chloride and a molecular sieve, the moisture of the solution is reduced to be less than 100ppm by using the anhydrous sodium sulfate, the anhydrous magnesium sulfate or the anhydrous calcium chloride, the moisture of the solution is reduced to be less than 10ppm by using the molecular sieve, and the mass concentration of the finished product of the ethyl methyl carbonate solution of the vinyl sulfate is 8-20%.

The obtained solid finished product is very convenient to package and convenient and accurate to weigh, a large amount of manpower and material resources can be saved, and exposure risk is reduced; is beneficial to the occupational health and the sanitation of operators, and can not introduce foreign matters in the packaging process.

The solid package of the invention does not have the caking phenomenon in the storage process and does not influence the use. When a user uses the vinyl sulfate to prepare the electrolyte, solid feeding is easier to accurately measure and convenient to operate. The preparation method has simple and controllable process route, solves the problems of low packaging efficiency, easy caking during storage, inconvenient use and the like of the solid product of the vinyl sulfate, and can obviously improve the use convenience of the vinyl sulfate as the electrolyte additive of the lithium ion battery.

Detailed Description

Example 1:

the following preparation method was used in this example: 50 g of ethylene sulfite, 300 g of methyl ethyl carbonate and 0.6 g of 5% ruthenium trichloride aqueous solution are added into a three-neck flask, magnetons are uniformly stirred at the low temperature of 0 ℃, 242 g of 15% effective chlorine content calcium hypochlorite aqueous solution is dropwise added, the temperature of a reaction system is controlled to be less than 5 ℃ in the dropwise adding process, and the low-temperature stirring reaction is continued for 2 hours after the dropwise adding is finished. Standing, separating, washing the organic phase with 200 g of pure water for 4 times, controlling the temperature in the washing process to be 2-8 ℃, drying the obtained organic phase with anhydrous sodium sulfite, then drying with a molecular sieve to obtain 327 g of a methyl ethyl carbonate solution of 13.5% by mass of ethylene sulfate, and detecting the water content to be 5ppm and the free acid to be 8 ppm.

Example 2

The following preparation method was used in this example: 50 g of ethylene sulfite, 250 g of methyl ethyl carbonate and 0.5 g of 5% ruthenium trichloride aqueous solution are added into a three-mouth flask, after magnetons are uniformly stirred at the low temperature of 0 ℃, 280 g of 13% effective chlorine content sodium hypochlorite aqueous solution is dripped, the temperature of a reaction system is controlled to be less than 5 ℃ in the dripping process, and after the dripping is finished, the low-temperature stirring reaction is continued for 2 hours. Standing, separating, washing the organic phase with 150 g of pure water for 5 times, controlling the temperature in the washing process to be 2-8 ℃, drying the obtained organic phase with anhydrous magnesium sulfite, then drying with a molecular sieve to obtain 260 g of a 15.4% mass concentration ethyl methyl carbonate solution of ethylene sulfate, and detecting the water content to be 6ppm and the free acid to be 7 ppm.

Example 3

The following preparation method was used in this example: 50 g of ethylene sulfite, 400 g of methyl ethyl carbonate and 1 g of 5% ruthenium trichloride aqueous solution are added into a three-mouth flask, after magnetons are uniformly stirred at the low temperature of 0 ℃, 400 g of 9% effective chlorine content potassium hypochlorite aqueous solution is dripped, the temperature of a reaction system is controlled to be less than 5 ℃ in the dripping process, and after the dripping is finished, the low-temperature stirring reaction is continued for 2 hours. Standing, separating, washing the organic phase with 300 g of pure water for 3 times, controlling the temperature in the washing process to be 2-8 ℃, drying the obtained organic phase with anhydrous calcium chloride, then drying with a molecular sieve to obtain 385 g of a 12.3% mass concentration ethyl methyl carbonate solution of ethylene sulfate, and detecting the water content to be 5ppm and the free acid to be 8 ppm.

The above description is only for the purpose of illustrating the technical solutions of the present invention and not for the purpose of limiting the same, and other modifications or equivalent substitutions made by those skilled in the art to the technical solutions of the present invention should be covered within the scope of the claims of the present invention without departing from the spirit and scope of the technical solutions of the present invention.