阅读说明：本技术 一种高纯度二氟代碳酸乙烯酯的制备方法 (Preparation method of high-purity difluoroethylene carbonate ) 是由 王海明 翟涛 纪加明 傅圣超 孔令文 林涛 于 2019-10-27 设计创作，主要内容包括：本发明公开了一种高纯度二氟代碳酸乙烯酯的制备方法,包括以下步骤：1)室温下将一定量的三乙胺三氢氟酸盐加入到容器中,加入适量的溶剂；2)向上述溶液中加入一定量的三乙胺,PH达到4～7,搅拌使之均匀；3)再向上述溶液中滴加一定量的高纯度二氯代碳酸乙烯酯,在一定反应温度下反应,使用气象色谱监控反应过程；4)反应结束后抽滤、洗涤,经过减压蒸馏后得到二氟代碳酸乙烯酯；5)产生的滤饼可回收得到三乙胺。本发明提供高纯度二氟代碳酸乙烯酯的制备方法,工艺简单、反应温度低、能耗低、环保、固废少、原子利用率高、收率高、适合企业大规模生产。(The invention discloses a preparation method of high-purity difluoroethylene carbonate, which comprises the following steps: 1) adding a certain amount of triethylamine trihydrofluoride into a container at room temperature, and adding a proper amount of solvent; 2) adding a certain amount of triethylamine into the solution, wherein the pH value reaches 4-7, and stirring to be uniform; 3) dropwise adding a certain amount of high-purity dichloroethylene carbonate into the solution, reacting at a certain reaction temperature, and monitoring the reaction process by using a gas chromatography; 4) after the reaction is finished, carrying out suction filtration and washing, and carrying out reduced pressure distillation to obtain difluoroethylene carbonate; 5) the generated filter cake can be recycled to obtain triethylamine. The preparation method of high-purity difluoroethylene carbonate provided by the invention has the advantages of simple process, low reaction temperature, low energy consumption, environmental protection, less solid waste, high atom utilization rate and high yield, and is suitable for large-scale production of enterprises.)

1. A preparation method of high-purity difluoroethylene carbonate is characterized by comprising the following steps: the method comprises the following steps:

s1: adding a certain amount of triethylamine trihydrofluoride into a container at room temperature, and adding a proper amount of solvent;

s2: adding a certain amount of triethylamine into the solution in the S1 until the PH value reaches 4-7, and stirring to be uniform;

s3: dropwise adding a certain amount of high-purity dichloroethylene carbonate into the solution in the S2, reacting at a certain reaction temperature, and monitoring the reaction process by using a gas chromatography;

s4: after the reaction of S3 is finished, carrying out suction filtration and washing, and carrying out reduced pressure distillation to obtain difluoroethylene carbonate;

s5: the filter cake produced in S4 can be recovered to yield triethylamine.

2. The process according to claim 1, wherein the ethylene difluorocarbonate is prepared in a high purity by: the purity of dichloroethylene carbonate in the step S3 is higher than 98%.

3. The process according to claim 2, wherein the ethylene difluorocarbonate is prepared in a high purity by: in the step S3, the equivalent ratio of dichloroethylene carbonate to triethylamine trihydrofluoric acid is 1.4: 1-1.5: 1.

4. The process according to claim 3, wherein the ethylene difluorocarbonate is prepared in a high purity by: the reaction temperature in the step S3 is 30-45 ℃.

5. The process according to claim 1, wherein the ethylene difluorocarbonate is prepared in a high purity by: the reaction endpoint is that the content of dichloroethylene carbonate in the step S3 is lower than 0.2%.

6. The process according to claim 1, wherein the ethylene difluorocarbonate is prepared in a high purity by: PH in step S2 is 5.

7. The process according to claim 1, wherein the ethylene difluorocarbonate is prepared in a high purity by: the reaction time in the step S3 is 3-5 h.

Technical Field

The invention relates to the field of lithium ion battery electrolyte additives, in particular to a preparation method of difluoroethylene carbonate which can be used as a lithium ion battery electrolyte additive.

Background

The difluoroethylene carbonate (DFEC) is an important lithium ion battery electrolyte additive, can improve the low-temperature performance of the electrolyte, improve the flash point of the electrolyte, enhance the cycle performance of the electrolyte and has good flame retardance.

In the conventional process (CN106905290A, CN107903240A), difluoroethylene carbonate is synthesized by carrying out fluorination reaction on dichloroethylene carbonate (DCEC) and solid fluoride (metal fluoride) under the condition of catalyst catalysis. However, the method has the disadvantages of long reaction time, more side reactions, troublesome treatment after the reaction, unrecoverable catalyst and the like.

Disclosure of Invention

The present invention is directed to a process for producing high-purity difluoroethylene carbonate, which solves the above-mentioned problems of the prior art.

In order to solve the technical problems, the invention provides the following technical scheme: a preparation method of high-purity difluoroethylene carbonate comprises the following steps:

s1: adding a certain amount of triethylamine trihydrofluoride into a container at room temperature, and adding a proper amount of solvent;

s2: adding a certain amount of triethylamine into the solution in the S1 until the PH value reaches 4-7, and stirring to be uniform;

s3: dropwise adding a certain amount of high-purity dichloroethylene carbonate into the solution in the S2, reacting at a certain reaction temperature, and monitoring the reaction process by using a gas chromatography;

s4: after the reaction of S3 is finished, carrying out suction filtration and washing, and carrying out reduced pressure distillation to obtain difluoroethylene carbonate;

s5: the filter cake produced in S4 can be recovered to yield triethylamine.

In a preferred embodiment of the present invention, the purity of dichloroethylene carbonate in step S3 is higher than 98%.

In a preferred embodiment of the present invention, the equivalent ratio of ethylene dichlorocarbonate to triethylamine trihydrofluoric acid in step S3 is 1.4:1 to 1.5: 1.

In a preferable technical scheme of the present invention, the reaction temperature in the step S3 is 30 to 45 ℃.

In a preferred embodiment of the present invention, the reaction endpoint is that the content of dichloroethylene carbonate in step S3 is less than 0.2%.

As a preferable embodiment of the present invention, the PH in step S2 is 5.

In a preferable technical scheme of the present invention, the reaction time in step S3 is 3 to 5 hours.

Compared with the prior art, the invention has the beneficial effects that: the invention provides a preparation method of high-purity difluoroethylene carbonate, which uses high-purity dichloroethylene carbonate as a raw material to prepare high-purity difluoroethylene carbonate, and high-purity dichloroethylene carbonate can be obtained without secondary rectification in the traditional process. The reaction temperature is 30-45 ℃, and compared with the reaction temperature of 70-80 ℃ in the traditional process, the reaction temperature is safer and the energy consumption is lower. Compared with other solid fluorinating agents, the triethylamine trihydrofluoride used as the fluorinating agent shortens the reaction time (homogeneous reaction), improves the reaction yield, reduces byproducts, reduces the solid waste of metal compounds and reduces the environmental pollution. Triethylamine in the filter cake can be recycled, so that the investment of raw and auxiliary materials is greatly reduced, and the atom utilization rate is greatly improved. The invention provides the preparation method of the difluoroethylene carbonate, which has the advantages of simple process, low reaction temperature, low energy consumption, environmental protection, less solid waste, high atom utilization rate and high yield and is suitable for large-scale production.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.