CN110684006A

CN110684006A - Preparation method of high-purity difluoroethylene carbonate

Info

Publication number: CN110684006A
Application number: CN201911027337.0A
Authority: CN
Inventors: 王海明; 翟涛; 纪加明; 傅圣超; 孔令文; 林涛
Original assignee: Huaian Han Kang Xin Materials Co Ltd
Current assignee: Huaian Han Kang Xin Materials Co Ltd
Priority date: 2019-10-27
Filing date: 2019-10-27
Publication date: 2020-01-14

Abstract

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.

Description

Preparation method of high-purity difluoroethylene carbonate

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.

Example 1

161.21g (1.0mol) of triethylamine trihydrofluoride and 350mL of dimethyl carbonate were placed in a 1L three-necked flask, 207.44g (2.05mol) of triethylamine was placed in the three-necked flask, the mixture was stirred to homogenize the mixture, the pH of the mixture was measured to be 5, 238.68g (1.45mol) of high-purity (98.35%) ethylene dichlorocarbonate was added dropwise to the three-necked flask, and the mixture was reacted at 45 ℃ for 3.5 hours to measure the content of ethylene dichlorocarbonate to be 0.08%, and the reaction was terminated. Then, the reaction solution is filtered, washed by dimethyl carbonate for 3 times, and subjected to reduced pressure distillation to obtain 177.22g of a crude product, wherein the content of difluoroethylene carbonate in the crude product is 98.15%, the molar yield is 96.74%, and finally triethylamine can be recovered from a filter cake.

Example 2

169.27g (1.05mol) of triethylamine trihydrofluoride and 350mL of dimethyl carbonate were placed in a 1L three-necked flask, 217.56g (2.15mol) of triethylamine was placed in the three-necked flask, and stirred to homogenize the mixture, and the pH was measured to be 5, and 247.66g (1.55mol) of high-purity (98.23%) ethylene dichlorocarbonate was dropped into the three-necked flask and reacted at 35 ℃ for 5 hours, and the ethylene dichlorocarbonate content was measured to be 0.09%, and the reaction was terminated. Then, the reaction solution is filtered, washed by dimethyl carbonate for 3 times, and subjected to reduced pressure distillation to obtain 189.54g of a crude product, wherein the content of difluoroethylene carbonate in the crude product is 98.25%, the molar yield is 96.89%, and finally triethylamine can be recovered from a filter cake.

Example 3

145.09g (0.9mol) of triethylamine trihydrofluoride and 300mL of dimethyl carbonate were placed in a 1L three-necked flask, 187.20g (1.85mol) of triethylamine was placed in the three-necked flask, the mixture was stirred to homogenize the mixture, the pH of the mixture was measured to be 6, 207.46g (1.3mol) of high-purity (98.35%) dichloroethylene carbonate was added dropwise into the three-necked flask, and the mixture was reacted at 40 ℃ for 4 hours to measure the content of dichloroethylene carbonate to be 0.13%, and the reaction was terminated. Then, the reaction solution is filtered, washed by dimethyl carbonate for 3 times, and subjected to reduced pressure distillation to obtain 159.38g of a crude product, wherein the content of difluoroethylene carbonate in the crude product is 98.17 percent, the molar yield is 97.06 percent, and finally triethylamine can be recovered from a filter cake.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Furthermore, it should be understood that although the present description refers to embodiments, not every embodiment may contain only a single embodiment, and such description is for clarity only, and those skilled in the art should integrate the description, and the embodiments may be combined as appropriate to form other embodiments understood by those skilled in the art.

Claims

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

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.