WO2022233341A1 - Method for purifying fluoroethylene carbonate and product obtained therefrom - Google Patents

Abstract

Provided in the present application are a method for purifying fluoroethylene carbonate and a product obtained therefrom, which belong to the technical field of preparation of electronic-grade reagents. The purification method comprises the following steps: subjecting a crude product of fluoroethylene carbonate to piezocrystallization to obtain crystals and an uncrystallized mother solution; sequentially subjecting the crystals to melting and heavy component removal to obtain a heavy-component-removed component; subjecting the uncrystallized mother solution to light component removal to obtain a light-component-removed component; and mixing the heavy-component-removed component with the light-component-removed component, and crystallizing the resulting mixed solution to obtain purified fluoroethylene carbonate. The purification method provided in the present application has a simple process and a high efficiency, and can effectively reduce energy consumption and cost, and is green and environmentally friendly.

Description

Method for purifying fluoroethylene carbonate and product therefrom

This application claims the priority of the Chinese patent application filed on July 26, 2021 with the application number of 202110844035.3 and the application title of "a method for purifying fluoroethylene carbonate and the products obtained therefrom", the entire contents of which are Incorporated herein by reference.

technical field

The application belongs to the technical field of preparation of electronic-grade reagents, and in particular relates to a purification method of fluoroethylene carbonate and a product obtained therefrom.

Background technique

Fluorinated ethylene carbonate is an important electrolyte film-forming additive for lithium-ion batteries, which can decompose in preference to other components of the electrolyte, forming a stable and continuous solid electrolyte interface film (SEI (solid electrolyte interface) at the electrode/electrolyte interface. interphase) membrane). The membrane has a small impedance, can effectively inhibit the decomposition of other components of the electrolyte, and can significantly improve the specific capacity and cycle stability of the battery. Therefore, fluoroethylene carbonate has been widely used in the battery industry.

However, as an electrolyte additive, the purity of fluoroethylene carbonate is required to be electronic grade. Therefore, it is necessary to purify and refine the crude product of fluoroethylene carbonate to meet the requirements for use. At present, the purification process of fluoroethylene carbonate is mainly rectification-crystallization method. For example, Chinese patent application CN110878078A discloses "a method for preparing electronic grade fluoroethylene carbonate by fractional crystallization". After rectifying the crude product of fluoroethylene carbonate, fractions of different purities are obtained, and then different fractions are subjected to fractional crystallization and drying to obtain High-purity fluoroethylene carbonate. Chinese patent application CN105801554A discloses "the purification method of high-purity fluoroethylene carbonate". After decolorization and water removal of crude fluoroethylene carbonate, distillation, dissolution and crystallization are carried out to obtain refined fluoroethylene carbonate. However, the above purification process is complicated and difficult to operate.

SUMMARY OF THE INVENTION

The present application provides a method for purifying fluoroethylene carbonate and a product obtained therefrom.

In order to achieve the above purpose, the technical scheme adopted in this application is:

A purification method of fluoroethylene carbonate, comprising the steps:

The fluoroethylene carbonate crude product is subjected to pressure crystallization to obtain crystallized and uncrystallized mother liquors;

The crystals are successively dissolved and deweighted to obtain deweighted components;

The uncrystallized mother liquor is delighted to obtain delighted components;

Mixing the deweighting component and the delighting component, and crystallizing the obtained mixed solution to obtain purified fluoroethylene carbonate;

The pressure during the pressurized crystallization is 1.5-5Mpa, and the temperature is 10-35°C.

In some embodiments of the present application, the melting method is reduced pressure melting, and the pressure of the reduced pressure melting is 0.05-0.1 MPa.

In some embodiments of the present application, the operating temperature during deweighting is 80-110° C., the pressure is 0.01-0.05 MPa, and the reflux ratio is 3-5.

In some embodiments of the present application, the operating temperature during delighting is 40-70° C., the pressure is 0.01-0.05 MPa, and the reflux ratio is controlled to 4-9.

In some embodiments of the present application, the mixed solution is crystallized by means of falling film crystallization.

In some embodiments of the present application, the temperature of the falling film crystallization is -10˜10° C., and the pressure is 0.001˜0.02 MPa.

The present application provides a fluoroethylene carbonate, which is prepared by the purification method described in the above scheme.

In some embodiments of the present application, the purity of the fluoroethylene carbonate is above 99.97%.

Compared with the prior art, the advantages and positive effects of the present application are:

(1) The method for purifying fluoroethylene carbonate provided in the examples of the present application does not need to introduce a third-party organic solvent, reduces process procedures and costs, and reduces environmental pollution.

(2) The pressurized crystallization process in the examples of the present application enables the product to be crystallized at a relatively high temperature, with low energy consumption, and simultaneously only requires a depressurization operation to cause the crystals to sweat and melt, thereby further effectively reducing energy consumption.

(3) In the embodiment of the present application, the heavy components and the light components in the product are separated through the crystallization process, and enter into the weight-removing tower and the light-removing tower respectively, so as to effectively improve the rectification purification efficiency and product purity.

Description of drawings

Fig. 1 is the purification process flow diagram of the fluoroethylene carbonate provided by the embodiment of the application.

Detailed ways

The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

The embodiments of the present application provide a method for purifying fluoroethylene carbonate, comprising the following steps:

The fluoroethylene carbonate crude product is subjected to pressure crystallization to obtain crystallized and uncrystallized mother liquors;

The crystals are successively dissolved and deweighted to obtain deweighted components;

The uncrystallized mother liquor is delighted to obtain delighted components;

Mixing the deweighting component and the delighting component, and crystallizing the obtained mixed solution to obtain purified fluoroethylene carbonate;

The pressure during the pressurized crystallization is 1.5-5Mpa, and the temperature is 10-35°C.

In the examples of the present application, the crude fluoroethylene carbonate is subjected to pressure crystallization to obtain crystallized and uncrystallized mother liquors. In the examples of the present application, the pressure during the pressurized crystallization is 1.5-5Mpa, preferably 3-4Mpa, and the temperature is 10-35°C, preferably 15-30°C.

After the crystallized and uncrystallized mother liquors are obtained, the present application sequentially dissolves and deweights the crystals to obtain a deweighted component; delights the uncrystallized mother liquor to obtain a deweighted component. In some embodiments of the present application, the melting method is preferably reduced pressure melting, and the pressure of the reduced pressure melting is preferably 0.05-0.1 MPa. In some embodiments of the present application, the operating temperature during deweighting is preferably 80-110°C, more preferably 90-100°C; the pressure during deweighting is preferably 0.01-0.05MPa, more preferably 0.03- 0.045Mpa, the reflux ratio is preferably 3 to 5, more preferably 4.

In some embodiments of the present application, the operating temperature during the de-lighting is preferably 40-70° C., more preferably 55-65° C.; the pressure during the de-lighting is preferably 0.01-0.05 MPa, more preferably 0.03- 0.04Mpa, the reflux ratio is preferably 4-9, more preferably 5-7.

After the deweighted component and the delighted component are obtained, in the examples of the present application, the deweighted component and the delighted component are mixed, and the obtained mixed solution is crystallized to obtain purified fluoroethylene carbonate. In the present application, it is preferable to crystallize the mixed solution by means of falling film crystallization. In some embodiments of the present application, the temperature of the falling film crystallization is preferably -10-10° C., more preferably 0-5° C., and the pressure is preferably 0.001-0.02 Mpa, more preferably 0.005-0.01 Mpa.

The method for purifying fluoroethylene carbonate provided in the examples of the present application adopts a pressurized method for crystallization, which can be crystallized at a relatively high temperature, has low energy consumption, does not need to introduce a third-party solvent, reduces process procedures and costs, and reduces environment Pollution. At the same time, only the depressurization operation can make the crystal sweat and melt, which further effectively reduces energy consumption. The crystallized product is then separated from heavy components and light components, and then enters the weight-removing tower and the light-removing tower respectively, which effectively improves the efficiency of rectification and purification and the purity of the product. As shown in Figure 1, it is a process flow diagram of the purification process of the fluoroethylene carbonate in the embodiment of the application.

The embodiment of the present application also provides a fluoroethylene carbonate, which is prepared by the purification method described in the above embodiment. In some embodiments of the present application, the purity of the fluoroethylene carbonate is above 99.97%.

In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below with reference to the examples, but they should not be construed as limiting the protection scope of the present application.

Example 1

(1) Fluorinated ethylene carbonate crude product (purity of fluorinated ethylene carbonate crude product is 90%) is sent into the pressurized crystallization process, the control pressure is 4MPa, the crystallization temperature is 30 ° C, and the crystallization product A, mother liquor B are obtained ;

(2) depressurizing the pressure to 0.1MPa, so that the crystalline product A is depressurized and melted and then sent to the weight-removing tower, and the operating temperature in the tower is controlled at 90° C., the pressure is 0.02MPa, and the reflux ratio is 3, and the heavy component is removed to obtain the product C;

(3) the mother liquor B is sent to the light-removing tower, and the operating temperature in the control tower is 40 ° C, the pressure is 0.01 MPa, and the reflux ratio is 6, and the light component is removed to obtain the product D;

(4) Mixing product C and product D, entering the falling film crystallization process, and controlling the temperature to 10° C. and the pressure to 0.01 MPa to obtain high-purity fluoroethylene carbonate with a chromatographic purity of 99.97%.

Example 2

(1) Fluorinated ethylene carbonate crude product (purity of fluorinated ethylene carbonate crude product is 89%) is sent into pressurized crystallization process, control pressure is 4MPa, crystallization temperature is 30 ℃, obtain crystallization product A, mother liquor B ;

(2) depressurize the pressure to 0.07MPa, make the crystalline product A depressurize and melt and then send it to the weight-removing tower, control the operating temperature in the tower at 85 ° C, the pressure at 0.03MPa, the reflux ratio of 4, and remove the heavy components to obtain product C;

(3) the mother liquor B is sent into the light-removing tower, and the operating temperature in the control tower is 40 ° C, the pressure is 0.03 MPa, and the reflux ratio is 5, and the light component is removed to obtain the product D;

(4) Mixing product C and product D, entering the falling film crystallization process, and controlling the temperature to 0°C and the pressure to 0.01MPa to obtain high-purity fluoroethylene carbonate with a chromatographic purity of 99.97%.

Example 3

(1) fluorinated ethylene carbonate crude product (purity of fluorinated ethylene carbonate crude product is 93%) is sent into pressurized crystallization process, control pressure is 3MPa, crystallization temperature is 20 ℃, obtain crystallization product A, mother liquor B ;

(2) depressurizing the pressure to 0.1MPa, so that the crystalline product A is depressurized and melted and then sent to the weight-removing tower, and the operating temperature is controlled to 90 ° C, the pressure is 0.03MPa, the reflux ratio is 4, and the heavy component is removed to obtain the product C;

(3) sending mother liquor B into light-removing tower, controlling operating temperature 55 ℃, pressure 0.01MPa, reflux ratio to be 7, and removing light components to obtain product D;

(4) Mixing product C and product D, entering the falling film crystallization process, and controlling the temperature to 5° C. and the pressure to 0.003 MPa to obtain high-purity fluoroethylene carbonate with a chromatographic purity of 99.98%.

Example 4

(1) fluorinated ethylene carbonate crude product (purity of fluorinated ethylene carbonate crude product is 93%) is sent into pressurized crystallization process, control pressure is 3MPa, crystallization temperature is 20 ℃, obtain crystallization product A, mother liquor B ;

(2) depressurize the pressure to 0.05MPa, so that the crystalline product A is depressurized and melted and then sent to the weight-removing tower, and the operating temperature is controlled at 95 ° C, the pressure is 0.03MPa, the reflux ratio is 5, and the heavy component is removed to obtain the product C;

(3) sending mother liquor B into light-removing tower, controlling operating temperature of 70 ° C, pressure of 0.04 MPa, and reflux ratio of 5, and removing light components to obtain product D;

(4) Mixing product C and product D, entering the falling film crystallization process, and controlling the temperature to 5° C. and the pressure to 0.003 MPa to obtain high-purity fluoroethylene carbonate with a chromatographic purity of 99.98%.

Example 5

(1) The crude product of fluoroethylene carbonate (the purity of the crude product of fluoroethylene carbonate is 95%) is sent to the pressurized crystallization process, the control pressure is 3MPa, and the crystallization temperature is 15° C. to obtain crystalline product A and mother liquor B ;

(2) depressurizing the pressure to 0.05MPa, so that the crystalline product A is depressurized and melted and then sent to the weight-removing tower, and the operating temperature is controlled at 95 ° C, the pressure is 0.04MPa, the reflux ratio is 5, and the heavy component is removed to obtain the product C;

(3) sending mother liquor B into light-removing tower, controlling operating temperature 55 ℃, pressure 0.05MPa, reflux ratio to be 7, slough off light component and obtain product D;

(4) Mixing product C and product D, entering the falling film crystallization process, and controlling the temperature to 10° C. and the pressure to 0.001 MPa to obtain high-purity fluoroethylene carbonate with a chromatographic purity of 99.97%.

The above are only the preferred embodiments of the present application. It should be pointed out that for those skilled in the art, without departing from the principles of the present application, several improvements and modifications can also be made. It should be regarded as the protection scope of this application.

Claims (8)

1. A kind of purification method of fluoroethylene carbonate, is characterized in that, comprises the steps:

   The fluoroethylene carbonate crude product is subjected to pressure crystallization to obtain crystallized and uncrystallized mother liquors;

   The crystals are successively dissolved and deweighted to obtain deweighted components;

   The uncrystallized mother liquor is delighted to obtain delighted components;

   Mixing the deweighting component and the delighting component, and crystallizing the obtained mixed solution to obtain purified fluoroethylene carbonate;

   The pressure during the pressurized crystallization is 1.5-5Mpa, and the temperature is 10-35°C.
2. The purification method according to claim 1, wherein the melting method is reduced pressure melting, and the pressure of the reduced pressure melting is 0.05-0.1 MPa.
3. The purification method according to claim 1, characterized in that, the operation temperature during the deweighting is 80-110°C, the pressure is 0.01-0.05MPa, and the reflux ratio is 3-5.
4. The purification method according to claim 1, characterized in that, the operating temperature during delighting is 40-70° C., the pressure is 0.01-0.05 MPa, and the reflux ratio is controlled at 4-9.
5. The purification method according to claim 1, wherein the mixed solution is crystallized by means of falling film crystallization.
6. The purification method according to claim 5, wherein the temperature of the falling film crystallization is -10-10°C, and the pressure is 0.001-0.02MPa.
7. A fluoroethylene carbonate, characterized in that it is prepared by the purification method described in any one of claims 1 to 6.
8. The fluoroethylene carbonate according to claim 7, wherein the purity of the fluoroethylene carbonate is above 99.97%.

Images