CN113121491A

CN113121491A - Method for producing fluoroethylene carbonate through micro-channel

Info

Publication number: CN113121491A
Application number: CN202010046691.4A
Authority: CN
Inventors: 夏永高; 王天桃
Original assignee: Ningbo Institute of Material Technology and Engineering of CAS
Current assignee: Ningbo Institute of Material Technology and Engineering of CAS
Priority date: 2020-01-16
Filing date: 2020-01-16
Publication date: 2021-07-16

Abstract

The invention provides a method for producing fluoroethylene carbonate by a microchannel, which comprises the following steps: and carrying out fluorination reaction on the ethylene carbonate and the fluorine gas under the irradiation of ultraviolet light in a microchannel reactor to obtain the fluoroethylene carbonate. According to the invention, the fluoroethylene carbonate is obtained by performing the microreactor photocatalytic fluorination reaction on the ethylene carbonate and the fluorine gas, and the product purity is high after subsequent treatment. The method has the advantages of simple synthesis process, continuous production, less three wastes, high yield and high product content of 99.95 percent.

Description

Method for producing fluoroethylene carbonate through micro-channel

Technical Field

The invention relates to the technical field of organic synthesis, in particular to a method for producing fluoroethylene carbonate by a microchannel.

Background

Fluoroethylene carbonate (FEC) is mainly applied to lithium electrolyte, and is required to be dozens of thousands of tons at home and abroad at present, and the content of the fluoroethylene carbonate (FEC) is 99.9 percent. With the understanding of people on environmental protection, the country has more and more support on environment-friendly products, and the lithium ion battery is rapidly promoted to advance in a wider range of directions such as electric bicycles and electric automobiles. However, the safety performance of the lithium ion battery is a major problem that hinders the development of the high-capacity lithium ion power battery, and particularly, the lithium ion battery often causes potential safety hazards such as ignition and explosion of the battery when overcharged, short-circuited, overdischarged or thermally shocked. Therefore, the solution to the problem of battery safety is the key point for developing and applying large-capacity lithium ion batteries. The approach for improving the safety performance of the lithium ion battery mainly comprises two simple methods: firstly, positive and negative electrode materials are optimized; and the other method is to optimize the electrolyte system of the lithium battery, namely to optimize the electrolyte additive.

The soliverine is prepared by adding 2 wt% of electrolyte additive FEC into electrolyte of 1mol/LLIPF6/+ DEC + DMC (volume ratio of 1:1: 1). The constant current charge-discharge method and the cyclic voltammetry are adopted to confirm that the addition of the FEC can form a layer of stable Solid Electrolyte Interface (SEI) film on the surface of the graphite electrode, thereby inhibiting the co-intercalation among solvent molecules to a great extent and improving the cycle performance of the battery. In addition, the FEC can simulate partial electrolyte decomposition, is flame-retardant, and improves the capacity and the safety performance of the battery.

At present, the method for synthesizing FEC in China mainly comprises the steps of synthesizing vinylene carbonate through chlorination of the vinylene carbonate and then synthesizing FEC through fluorination, and patents CN201510114056 and CN201710009977 show that the method has uncontrollable reaction degree, large pollution and complex post-treatment; and the other method is to adopt fluorinated metal salt as a fluorine source to perform fluorine substitution reaction with chloroethylene carbonate to obtain FEC, and the method has simple reaction and easy post-treatment, but the conversion rate of chloroethylene carbonate is not high and is only about 80-85%. The conversion rate of potassium fluoride in fluorination is not high, and is about 85-89%. But the three wastes of potassium fluoride and potassium chloride are difficult to separate.

Disclosure of Invention

In view of the above, the technical problem to be solved by the present invention is to provide a method for producing fluoroethylene carbonate through a microchannel, wherein the method provided by the present invention can realize continuous production, and has the advantages of less three wastes, high yield and less side reactions.

The invention provides a method for producing fluoroethylene carbonate by a microchannel, which comprises the following steps:

and carrying out fluorination reaction on the ethylene carbonate and the fluorine gas under the irradiation of ultraviolet light in a microchannel reactor to obtain the fluoroethylene carbonate.

Preferably, the molar concentration of the ethylene carbonate and the fluorine gas is 1: 0.6 to 0.9.

Preferably, the wavelength of the ultraviolet light is 300-360 nm, and the light intensity is 300-2000 w.

Preferably, the reaction temperature is 45-70 ℃.

Preferably, the reaction time is 2-20 min.

Preferably, the microchannel reactor material is polytetrafluoroethylene and glass.

Preferably, the method further comprises pretreating the microchannel reactor before the reaction, wherein the pretreatment specifically comprises: and (4) replacing and cleaning the microreactor with nitrogen.

Preferably, the ethylene carbonate is pumped into the microreactor by a micropump; the flow rate of the ethylene carbonate is 60-100 mL/min.

Preferably, the fluorine gas is carried by a steel cylinder, and the flow rate of the fluorine gas is 10 to 30 mL/min.

Preferably, the reaction time of the microchannel reactor from the inlet to the outlet is 3 min.

Compared with the prior art, the invention provides a method for producing fluoroethylene carbonate by a microchannel, which comprises the following steps: and carrying out fluorination reaction on the ethylene carbonate and the fluorine gas under the irradiation of ultraviolet light in a microchannel reactor to obtain the fluoroethylene carbonate. According to the invention, the fluoroethylene carbonate is obtained by performing the microreactor photocatalytic fluorination reaction on the ethylene carbonate and the fluorine gas, and the product purity is high after subsequent treatment. The method has the advantages of simple synthesis process, short reaction time, high safety, continuous production, less three wastes, high yield and high product content of 99.95 percent.

Detailed Description

The invention provides a method for producing fluoroethylene carbonate by a microchannel, and a person skilled in the art can use the content to reference the text and appropriately modify the process parameters to realize the method. It is expressly intended that all such similar substitutes and modifications apparent to those skilled in the art are deemed to be within the scope of the invention. While the methods and applications of this invention have been described in terms of preferred embodiments, it will be apparent to those of ordinary skill in the art that variations and modifications in the methods and applications described herein, as well as other suitable variations and combinations, may be made to implement and use the techniques of this invention without departing from the spirit and scope of the invention.

The fluoroethylene carbonate of the invention is CAS number 114435-02-8, chemical name 4-fluoro-1, 3-dioxolan-2-one.

The present invention provides a microchannel reactor, which is not limited by the present invention, but is well known to those skilled in the art.

The microchannel reactor material of the invention is preferably polytetrafluoroethylene and glass.

The method of the present invention preferably further comprises a step of pretreating the microchannel reactor before the reaction, wherein the pretreatment is preferably specifically as follows: and (4) replacing the microreactor with nitrogen and cleaning. The present invention is not limited to the particular manner of displacement and cleaning described, as would be known to one skilled in the art.

The invention leads ethylene carbonate and fluorine gas to have fluoro-reaction under the irradiation of ultraviolet light in a micro-channel reactor.

First, ethylene carbonate was pumped into the microreactor by a micropump to prepare for opening the microchannel reactor simultaneously with fluorine gas. And (4) connecting the fluorine gas steel cylinder with a flowmeter, and preparing to open the fluorine gas steel cylinder and the ethylene carbonate simultaneously to enter the microchannel reactor.

The flow rate of the ethylene carbonate is 60-100 mL/min.

The flow rate of the fluorine gas is 10 to 30 mL/min.

According to the present invention, the molar concentrations of ethylene carbonate and fluorine gas are preferably in the range of 1: 0.6 to 0.9; more preferably 1:0.75 to 0.85.

Heating the microchannel reactor to a temperature of preferably 45-70 ℃; more preferably 60-65 ℃; the reaction time is preferably 2-20 min; more preferably 2 to 15 min.

The wavelength of the ultraviolet light is 300-360 nm, and the light intensity is 300-2000 w. The microchannel reactor was started to react for 3min from the inlet to the outlet. The outlet receives the product via a condenser. The present invention is not limited to the above-mentioned condensing method, and the condensing method is well known to those skilled in the art.

The ultraviolet light is arranged outside the microchannel reactor, and only one surface is needed.

The side reaction hydrogen fluoride is treated by the absorption tower to obtain the hydrofluoric acid product.

And (3) separating excessive ethylene carbonate with a boiling point of 151-152 ℃ by a distillation tower to obtain the next re-reaction. The boiling point of fluoroethylene carbonate flowing out of the distillation tower is 211-212 ℃,

the invention provides a method for producing fluoroethylene carbonate by a microchannel, which comprises the following steps: and carrying out fluorination reaction on the ethylene carbonate and the fluorine gas under the irradiation of ultraviolet light in a microchannel reactor to obtain the fluoroethylene carbonate. According to the invention, the fluoroethylene carbonate is obtained by performing the microreactor photocatalytic fluorination reaction on the ethylene carbonate and the fluorine gas, and the product purity is high after subsequent treatment. The method has the advantages of simple synthesis process, short reaction time, high safety, continuous production, less three wastes, high yield and high product content of 99.95 percent.

In order to further illustrate the present invention, the following will describe the method for producing fluoroethylene carbonate by using micro-channel provided by the present invention in detail with reference to the following examples. The microreactor of the present invention was purchased from Shandong Haomai chemical.

Example 1

The microchannel reactor was fitted with a glass microreactor and purged with nitrogen displacement. 352Kg (4mol) of ethylene carbonate is filled in a plastic barrel, and a micro pump is switched on to prepare for opening the micro-channel reactor simultaneously with fluorine gas. A fluorine gas 114Kg (3mol) steel cylinder is connected with a flowmeter and is ready to be simultaneously opened with ethylene carbonate to enter a microchannel reactor. And heating the microchannel reactor to 60-65 ℃. The wavelength of the ultraviolet light is 300-360 nm, and the light intensity is 300-2000 w. The microchannel reactor was started to react for 3min from the inlet to the outlet. The outlet condenser receives the product, and the side reaction hydrogen fluoride is processed by the absorption tower to obtain a hydrofluoric acid product. The boiling point of the fluoroethylene carbonate product is 151-152 ℃ after the fluoroethylene carbonate product is separated by a distillation tower, and 88Kg (1mol) is obtained for the next reaction. The boiling point of fluoroethylene carbonate discharged from the distillation tower is 211-212 ℃, 300Kg is obtained, and the yield is 94.29%. The content is 99.95%.

Example 2

The microchannel reactor was fitted with a glass microreactor and purged with nitrogen displacement. 352Kg (4mol) of ethylene carbonate is filled in a plastic barrel, and a micro pump is switched on to prepare for opening the micro-channel reactor simultaneously with fluorine gas. A fluorine gas 133Kg (3.5mol) steel cylinder is connected with a flowmeter and is ready to be simultaneously opened with ethylene carbonate to enter a microchannel reactor. And heating the microchannel reactor to 60-65 ℃. The wavelength of the ultraviolet light is 300-360 nm, and the light intensity is 300-2000 w. The microchannel reactor was started to react for 3min from the inlet to the outlet. The outlet receives the product through a condenser, and the side reaction hydrogen fluoride is processed through an absorption tower to obtain a hydrofluoric acid product. The fluoroethylene carbonate product is separated by a distillation tower, excessive ethylene carbonate boils at 151-152 ℃, and 44Kg (0.5mol) of ethylene carbonate is obtained for the next reaction. The boiling point of fluoroethylene carbonate flowing out of the distillation tower is 211-212 ℃, 329Kg is obtained, and the yield is 88.68%. The content is 99.05%.

Comparative example 1

And (3) directly carrying out fluorine substitution reaction on the mixed gas of the fluorine gas and the inert gas and the ethylene carbonate at the temperature of 60-65 ℃ to obtain the fluoroethylene carbonate. The wavelength of the ultraviolet light is 300-360 nm, and the light intensity is 300-2000 w. The yield thereof was found to be 54.32%. The content is 95.24%.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A method for producing fluoroethylene carbonate by a microchannel, which is characterized by comprising the following steps:

2. The method according to claim 1, wherein the molar concentration of ethylene carbonate and fluorine gas is in the range of 1: 0.6 to 0.9.

3. The method of claim 1, wherein the ultraviolet light has a wavelength of 300 to 360nm and a light intensity of 300 to 2000 w.

4. The method according to claim 1, wherein the reaction temperature is 45 to 70 ℃.

5. The method according to claim 4, wherein the reaction time is 2-20 min.

6. The method of claim 1, wherein the microchannel reactor material is polytetrafluoroethylene and glass.

7. The method according to claim 1, further comprising, prior to the reaction, pretreating the microchannel reactor, the pretreating being specifically: and (4) replacing and cleaning the microreactor with nitrogen.

8. The method of claim 1, wherein the ethylene carbonate is pumped into the microreactor by a micropump; the flow rate of the ethylene carbonate is 60-100 mL/min.

9. The method of claim 1, wherein the fluorine gas is carried by a steel cylinder and the flow rate of the fluorine gas is 10 to 30 mL/min.

10. The method of claim 1, wherein the microchannel reactor has a reaction time from inlet to outlet of 3 min.