WO2014166086A1

WO2014166086A1 - Method for preparing tri(hexafluoroisopropyl)phosphate

Info

Publication number: WO2014166086A1
Application number: PCT/CN2013/074056
Authority: WO
Inventors: 陈群; 汪仕华
Original assignee: 深圳新宙邦科技股份有限公司
Priority date: 2013-04-07
Filing date: 2013-04-11
Publication date: 2014-10-16
Also published as: CN103275116B; CN103275116A

Abstract

An object of the invention consists in providing a processing method for preparing tri(hexafluoroisopropyl) phosphate in a large scale, which is safe, low-cost, and high-yield. In order to achieve the above inventive object, the invention provides a method for preparing tri(hexafluoroisopropyl)phosphate, comprising the following steps: in an inert gas atmosphere, mixing hexafluoroisopropanol and methyl tertiary butyl ether; in the inert gas atmosphere, adding a metal hydride into the mixture of hexafluoroisopropanol and methyl tertiary butyl ether for a reaction, to obtain a first reaction solution; in the inert gas atmosphere, adding phosphorus oxychloride into the first reaction solution for a reaction by heating and refluxing, to obtain a second reaction solution; filtering the second reaction solution so as to obtain a filtrate; fractionating the filtrate at normal pressure and collecting fractions at a temperature of 78°C-88°C; cooling and crystallising the fractions collected in the range of 78°C-88°C; separating the crystals from the mother liquor, to obtain the crystals; heating the crystals to obtain a molten liquid and collecting products satisfying the preset requirement of purity.

Description

Process for preparing tris(hexafluoroisopropyl)phosphate

The present invention relates to a method for synthesizing an organic compound and a method for purifying the same, and in particular to a method for synthesizing and purifying tris(hexafluoroisopropyl)phosphate. Background technique

Tris(hexafluoroisopropyl)phosphate is a new type of lithium ion battery electrolyte additive that significantly improves the performance of lithium ion batteries. Tris(hexafluoroisopropyl)phosphate has a certain flame retardant effect and can form a good protective film on the electrode of lithium ion battery, so it can be widely used as a high voltage lithium ion battery, a safe flame retardant lithium ion battery, and High-power lithium-ion battery and other lithium-ion battery electrolytes.

The literature (Journal of The Electrochemical Society, 158, A337-A342, 2011) discloses a preparation process of tris(hexafluoroisopropyl)phosphate, using diethyl ether as a reaction solvent, and hexafluoroisopropanol first with lithium hydride. The reaction is then reacted with phosphorus oxychloride to form tris(hexafluoroisopropyl)phosphate. After the reaction mixture was filtered to remove the lithium salt, tris(hexafluoroisopropyl)phosphate was purified by distillation and sublimation.

The preparation and purification methods of tris(hexafluoroisopropyl)phosphate reported in the above literature have a number of disadvantages. First, the boiling point of ether is too low, and the vapor is easily oxidized when exposed to the air, and is more likely to explode after being heated. In addition, acetic acid as a refluxing reaction solvent has a reflux temperature of only 34.6 ° C, which is disadvantageous for increasing the yield of tris(hexafluoroisopropyl)phosphate. Therefore, diethyl ether is not suitable as a reaction solvent. Moreover, it is difficult to obtain tris(hexafluoroisopropyl)phosphate having a purity of more than 99% by repeated atmospheric or vacuum distillation, and the depressurization sublimation operation cost is high, the product loss is large, and it is not easy to mass-purify the preparation of three ( Hexafluoroisopropyl) phosphate. Summary of the invention

It is an object of the present invention to provide a process which is safe, low cost, high in yield and capable of producing tris(hexafluoroisopropyl)phosphate in large quantities.

In order to achieve the above object, the present invention provides a preparation of tris(hexafluoroisopropyl)phosphate The method includes the following steps:

The hexafluoroisopropanol and the ether solvent are mixed in an inert gas atmosphere, and the ether solvent is one or more selected from the group consisting of: mercapto tert-butyl acid, tetrahydrofuran, 1,4-dioxane , n-propyl ether, n-butyl ether, ethylene glycol dioxime ether, ethylene glycol diethyl ether;

Adding a metal hydride or a tertiary amine to a mixture of hexafluoroisopropanol and ether in an inert gas atmosphere to carry out a reaction to obtain a first reaction liquid;

Adding phosphorus oxychloride to the first reaction liquid in an inert gas atmosphere, and heating and refluxing to obtain a second reaction liquid;

Filtering the second reaction liquid to obtain a filtrate;

The filtrate is heated and fractionated, and a crude fraction containing tris(hexafluoroisopropyl)phosphate is collected; the collected crude fraction is cooled and crystallized;

Separating the crystal from the mother liquor to obtain a crystal;

The crystal is warmed to obtain melted sweat, and tris(hexafluoroisopropyl) is collected according to the preset purity requirement. In the present invention, the fractionation operation may be atmospheric pressure fractionation or vacuum fractionation, depending on the nature of the material and the equipment. In order to reduce the cost, a low boiling ether solvent is recovered in the fractionation step.

The invention has the following advantages:

The ether solvent used in the present invention is inexpensive, and is effective as a reaction solvent to reduce the production cost; the ether solvent used in the present invention is stable in air compared to diethyl ether, and the production solvent is remarkably improved as a reaction solvent; The solvent has a moderate boiling point, which not only ensures a higher conversion rate of the reflux reaction, but also easily separates from the product.

Crystallized sweating is combined with a vacuum distillation process to produce high purity tris(hexafluoroisopropyl)phosphate in a fast, low cost, high yield.

Preferably, the ether solvent is mercapto tert-butyl ether.

Preferably, the temperature of the mixed hexafluoroisopropanol and the ether solvent is controlled at 0 to 30 °C.

Preferably, the volume ratio of hexafluoroisopropanol to the ether solvent is from 1:1 to 5.

More preferably, the volume ratio of hexafluoroisopropanol to ether solvent is 1:2.

Preferably, the metal hydride is selected from one or more of the following: lithium hydride, sodium hydride, Potassium hydride, calcium hydride and lithium aluminum hydride.

More preferably, the metal hydride is selected from the group consisting of lithium hydride, sodium hydride or a mixture of the two.

Preferably, the tertiary amine is selected from one or more of the following: tridecylamine, triethylamine, pyridine, nitrogen, nitrogen-dimercaptopyridine.

Preferably, a metal hydride or a tertiary amine is added to the mixture of hexafluoroisopropanol and ether, and the reaction temperature is 0 to 30 ° C, and the reaction time is 1 to 5 hours.

Preferably, in the step of adding a metal hydride or a tertiary amine to the mixture of hexafluoroisopropanol and ether, the effective molar ratio of the metal hydride to hexafluoroisopropanol is from 0.9 to 1.2:1. The effective molar ratio is the molar ratio of the reactive groups participating in the reaction, for example, the molar ratio of the hydrogen anion to the hexafluoroisopropanol in the metal hydride is the effective molar ratio (for example, the calcium hydride contains two hydride ions, the molar ratio is 0.5 : 1 , effective molar ratio is 1: 1 , )

More preferably, in the step of adding a metal hydride or a tertiary amine to the mixture of the hexafluoroisopropanol and the ether solvent, the molar ratio of the metal hydride or the tertiary amine to the hexafluoroisopropanol is 1:1. .

Preferably, the phosphorus oxychloride is added to the first reaction liquid, and the step of heating and refluxing is specifically: adding phosphorus oxychloride to the first reaction liquid, and the temperature during the dropwise addition is controlled at 0 to 30 ° C, and dropping After the addition is completed, the mixture is heated at 60 to 80 ° C for refluxing for 1 to 5 hours.

Preferably, when phosphorus oxychloride is added to the first reaction solution, the molar ratio of phosphorus oxychloride to hexafluoroisopropanol added is 0.3 to 0.4:1.

Preferably, when phosphorus oxychloride is added to the first reaction liquid, the molar ratio of phosphorus oxychloride to hexafluoroisopropanol added is 0.33:1.

Preferably, the second reaction liquid is cooled before the step of filtering the second reaction liquid.

Preferably, the filtrate is subjected to atmospheric pressure fractionation to recover an ether solvent having a lower boiling point than tris(hexafluoroisopropyl)phosphate, and the heating temperature is 60-100 °C.

Preferably, the fractionation operation is carried out by fractional distillation under normal pressure, and an ether solvent such as mercapto tert-butyl ether is collected. After the ether solvent is collected, the filtrate is subjected to fractional distillation under reduced pressure to collect a fraction of 78-88 ° C. At the time, the heating temperature is 100-120 °C. The boiling point of trihexafluoroisopropyl phosphate is more than 100 degrees at normal pressure, and here should be fractional distillation under reduced pressure. For example, the vacuum of the laboratory pump is about 4000 Pa. However, the boiling point of mercapto tert-butyl ether is only 50 degrees under normal pressure, and it will be bumped at room temperature under decompression, and will be pumped into the air with vacuuming, so Before this step, the ether solvent in the reaction liquid is recovered by atmospheric pressure fractionation, and then the product is fractionally distilled under reduced pressure.

Preferably, the step of cooling and crystallization of the fraction collected in the range of 78-88 ° C is specifically as follows: the initial temperature of the crystallization environment is set to 20-25 ° C, and after 1-3 hours of constant temperature, the crystallization temperature is decreased by 0.5- every 15 to 45 minutes. At 2 °C, the final temperature of the crystallization environment is set to 10-15 °C, and the final temperature is 1-3 hours.

Preferably, the step is to raise the temperature of the crystal to obtain melted sweat, and collect the tris(hexafluoroisopropyl) phosphate which meets the preset purity, and the purity of the tris(hexafluoroisopropyl) phosphate is preset. More than 99%.

Preferably, when the second reaction solution is filtered, the filter residue is washed with an ether solvent, and the obtained washing liquid is incorporated into the filtrate;

The step of separating the crystal and the mother liquor obtained from the mother liquor is added to the filtrate obtained in the step of filtering the second reaction solution;

The step is to heat the crystal to obtain melted sweat, collect tris(hexafluoroisopropyl) phosphate which meets the preset purity, collect sweat which does not meet the preset purity, and add it to 78-88 °. The fractions collected in the C range are crystallized together.

Preferably, in the step of subjecting the filtrate to atmospheric pressure fractionation, an ether solvent is recovered and added to the mixture obtained in the step of mixing hexafluoroisopropanol with an ether solvent in an inert gas atmosphere.

In the above preferred embodiment, the recycling of the reaction solvent and the intermediate material recycles the yield of the tris(hexafluoroisopropyl)phosphate while reducing the disposal and discharge of the waste.

The inert gas atmosphere may be a gas atmosphere which does not chemically react with the reactants, such as nitrogen, helium, neon, argon or the like. Preferably, the inert gas atmosphere is a nitrogen atmosphere. detailed description

The technical contents, structural features, objects and effects achieved by the present invention will be described in detail below with reference to the embodiments.

The invention discloses the preparation of tris(hexafluoroisopropyl)phosphate and a purification method thereof, thereby realizing high-purity tris(hexafluoroisopropyl)phosphate safely, at low cost and in high yield, and is easy to realize large The scale of industrial production, the specific method is as follows: (1) Under nitrogen protection and stirring, hexafluoroisopropanol and acid were added to the reaction vessel as a reaction solvent to obtain a mixed liquid, and the temperature was controlled at 0 to 30 °C. Wherein the ether comprises mercapto tert-butyl ether, tetrahydrofuran, 1,4-dioxane, n-propyl ether, n-butyl ether, ethylene glycol dioxime ether, ethylene glycol diethyl ether, preferably mercapto tert-butyl ether Wherein, the volume ratio of hexafluoroisopropanol to ether is from 1:1 to 5, preferably 1:2.

(2) A metal hydride or a tertiary amine is added to the mixture obtained in the step (1) under nitrogen protection and stirring, and the temperature is controlled at 0 to 30 ° C for 1-5 hours. Wherein, the metal hydride comprises lithium hydride, sodium hydride, potassium hydride, calcium hydride, lithium aluminum hydride, etc., preferably lithium hydride and sodium hydride; wherein the tertiary amine includes tridecylamine, triethylamine, pyridine, nitrogen, nitrogen- Dimercaptopyridine; wherein the effective molar ratio of metal hydride or tertiary amine to hexafluoroisopropanol is from 0.9 to 1.2:1, preferably 1:1.

(3) Under nitrogen protection and stirring, slowly add phosphorus oxychloride to the reaction mixture obtained in step (2), the temperature is controlled at 0-30 °C, and the mixture is heated at 60-80 °C after the addition is completed. It is refluxed for 1-5 hours. Wherein, the molar ratio of phosphorus oxychloride to hexafluoroisopropanol is from 0.3 to 0.4:1, preferably 0.33:1.

(4) Cooling step (3) The obtained reaction mixture was allowed to reach room temperature, and the filtrate was collected by suction filtration under reduced pressure. The residue was washed with a small amount of ether and then filtered and filtered.

(5) Heating step (4) The obtained filtrate is subjected to distillation under normal pressure to collect a low-boiling fraction for recovering the reaction solvent described in the step (1). Among them, the heating temperature is 60-100 ° C, preferably 80 ° C.

(6) The residue after atmospheric distillation is heated under reduced pressure at 4000 Pa to collect the 78-88 crude fraction. Among them, the heating temperature is 100 to 120 ° C, preferably 110 ° C.

(7) The crude fraction obtained in the step (6) is poured into a crystallizer to be gradually cooled, and most of the colorless or white crystals are precipitated. Among them, the initial temperature of the crystallizer is set to 20-25 °C, after 1-3 hours of constant temperature, the temperature of the mold is lowered by 0.5-2 °C every 15-45 minutes, and the final temperature of the crystallizer is set to 10-15 °C. 1-3 hours.

(8) After the mother liquid is collected by the inverted crystallizer, the crystallizer is gradually heated, and the colorless or white crystal obtained in the step (7) is gradually melted and sweated, and the sweat is collected in order to obtain tris(hexafluoroisopropyl) having a main content of 99% or more. Phosphate ester, the collected mother liquor can be combined with the filtrate of step (4), and the sweat having a main content of less than 99% can be combined with the crude fraction of step (6). Among them, the initial temperature of the crystallizer is set to 25-30 ° C, after 1-3 hours of constant temperature, the mold temperature rises by 0.5-2 ° C every 15-45 minutes, and the final temperature of the crystallizer is set to 40-50 ° C, and finally Constant temperature 1-3 hours. The detailed description of the specific embodiments is given below.

Example 1

A 2000 ml three-necked flask was placed in an ice water bath, and 800 ml of mercapto tert-butyl ether and 420 ml of hexafluoroisopropanol were added thereto, and magnetically stirred uniformly, 32 g of lithium hydride was added. The reaction was continuously stirred for 1 hour, and 204 g of phosphorus oxychloride was added dropwise to the reaction solution. After the dropwise addition, the mixture was heated to reflux with a 60 ° C oil bath for 5 hours. The reaction solution was cooled to room temperature, and filtered under reduced pressure to give a filtrate. The residue was washed with 200 ml of decyl-tert-butyl ether and filtered under reduced pressure. The filtrate was heated in an oil bath at 80 ° C for atmospheric distillation to recover decyl tert-butyl ether. The residual liquid was subjected to vacuum distillation under an oil bath heated at 110 ° C and a pressure of 4000 Pa, and a crude fraction of 440 g at 78-88 ° C was collected. All the crude fractions were transferred to a 1 L crystallizer. After cooling at 20 ° C for 1 hour, the crystallizer was lowered by 1 ° C every 30 minutes until the crystallizer temperature was 10 ° C, and the temperature was cooled for 1 hour to precipitate a large amount of colorless. Or white crystals. The crystallizer was inverted and 88 g of the mother liquor was collected, which was combined with the filtered filtrate. Set the temperature of the crystallizer to 30 °C, and after heating at constant temperature for 1 hour, raise the crystallizer by 1 °C every 30 minutes until the temperature of the crystallizer is 50 °C, and heat it at constant temperature for 1 hour, and collect the sweat out in sequence to obtain 266 g of tris(hexafluoroisopropyl) phosphate having a purity of 99% or more, and the remaining sweat can be combined with the crude fraction.

Example 2:

25 ^Q C A 2000 ml three-necked flask was placed in an ice water bath at room temperature, and 420 ml of mercapto tert-butyl ether and 420 ml of hexafluoroisopropanol were added thereto, and mechanically stirred uniformly, 28.8 g of lithium hydride was added. The reaction was continuously stirred for 1 hour, and 185 g of phosphorus oxychloride was slowly added dropwise to the reaction liquid. After the completion of the dropwise addition, the mixture was heated to reflux with a 70 ° C oil bath for 3 hours. The reaction solution was cooled to room temperature, and filtered under reduced pressure to give a filtrate, which was washed with 400 ml of decyl-tert-butyl ether and filtered under reduced pressure. The filtrate was heated in an oil bath at 80 ° C for atmospheric distillation to recover decyl tert-butyl ether. The residual liquid was subjected to vacuum distillation under an oil bath heated at 110 ° C and a pressure of 4000 Pa, and 350 g of a crude fraction of 78-88 ° C was collected. All the crude fractions were transferred to a 1 L crystallizer. After cooling at 20 ° C for 1 hour, the crystallizer was lowered by 1 ° C every 30 minutes until the crystallizer temperature was 10 ° C, and the temperature was cooled for 1 hour to precipitate a large amount of colorless. Or white crystals. The crystallizer was inverted and 70 g of the mother liquor was collected, and the filtrate was combined with the filtered filtrate. Set the temperature of the crystallizer to 30 °C, and after heating at constant temperature for 1 hour, raise the crystallizer by 1 °C every 30 minutes until the temperature of the crystallizer is 50 °C, and heat it at constant temperature for 1 hour, and collect the sweat out in sequence to obtain More than 99% purity of tris(hexafluoroisopropyl) phosphate 210 g, the rest Sweat can be combined with the crude fraction.

Example 3:

At room temperature of 25 ° C, a 2000 ml three-necked flask was placed in an ice water bath, and 1200 ml of tetrahydrofuran and 420 ml of hexafluoroisopropanol were added thereto, and mechanically stirred uniformly, and then 320 g of pyridine was added. The reaction was continuously stirred for 1 hour, and 204 g of phosphorus oxychloride was slowly added dropwise to the reaction liquid. After the completion of the dropwise addition, the mixture was heated to reflux with a 70 ° C oil bath for 3 hours. The reaction solution was cooled to room temperature, and the filtrate was filtered under reduced pressure. The filtrate was washed with 400 ml of tetrahydrofuran and filtered under reduced pressure. The filtrate was heated in an oil bath at 80 ° C for atmospheric distillation to recover tetrahydrofuran. The residual liquid was subjected to vacuum distillation under an oil bath heated at 110 ° C and a pressure of 4000 Pa, and a crude fraction of 300 g at 78-88 ° C was collected. All the crude fractions were transferred to a 1 L crystallizer. After cooling at 20 ° C for 1 hour, the crystallizer was lowered by rc every 30 minutes until the temperature of the crystallizer was 10 ° C, and the temperature was cooled for 1 hour to precipitate a large amount of colorless or white. Crystal. The crystallizer was inverted and collected to collect 80 g of the mother liquor, which was combined with the filtrate after filtration. Set the temperature of the crystallizer to 30 °C, and after heating at constant temperature for 1 hour, raise the crystallizer by rC every 30 minutes until the temperature of the crystallizer is 50 °C, and heat it at constant temperature for 1 hour, and collect the sweat out in sequence to obtain 99%. The above purity of tris(hexafluoroisopropyl) phosphate was 130 g, and the remaining sweat was combined with the crude fraction.

Example 4:

A 5000 ml three-necked flask was placed in an ice water bath, and 2400 ml of mercapto tert-butyl ether and 1260 ml of hexafluoroisopropanol were added thereto, and mechanically stirred uniformly, and then 96 g of lithium hydride was added. The reaction was continuously stirred for 1 hour, and 612 g of phosphorus oxychloride was added dropwise to the reaction solution. After the completion of the dropwise addition, the mixture was heated to reflux with a 60 ° C oil bath for 5 hours. The reaction solution was cooled to room temperature, and filtered under reduced pressure to give a filtrate. The residue was washed with 600 ml of decyl-tert-butyl ether and filtered under reduced pressure. The filtrate was heated in an oil bath at 80 ° C for atmospheric distillation to recover decyl tert-butyl ether. The residual liquid was subjected to vacuum distillation under heating at 110 ° C in an oil bath and pressure at 4000 Pa, and 1520 g of a crude fraction of 78-88 ° C was collected. All the crude fractions were transferred to a 2 L crystallizer. After cooling at 20 ° C for 1 hour, the crystallizer was lowered to rC every 45 minutes until the crystallizer temperature was 10 ° C, and the temperature was cooled for 1 hour to precipitate a large amount of colorless or white. Crystal. The crystallizer was inverted and 263 g of the mother liquor was collected, and the filtrate was combined with the filtered filtrate. Set the temperature of the crystallizer to 30 °C, and after heating at constant temperature for 1 hour, raise the crystallizer by rC every 45 minutes until the temperature of the crystallizer is 50 °C, and heat it at constant temperature for 1 hour, and collect the sweat that flows out in turn to obtain 99%. 805 g of the above purity of tris(hexafluoroisopropyl)phosphate, the remaining sweat can be Rough points are combined and applied.

The above is only the embodiment of the present invention, and thus does not limit the scope of the patent of the present invention. Any equivalent structure or equivalent process transformation made by using the content of the specification of the present invention, or directly or indirectly applied to other related technical fields, The same is included in the scope of patent protection of the present invention.

Claims

claims

1. A method for preparing tris(hexafluoroisopropyl)phosphate, which is characterized by comprising the following steps: in an inert gas atmosphere, mixing hexafluoroisopropanol and an ether solvent, the ether solvent being selected from the group consisting of: One or more of the following substances: methyl tert-butyl acid, tetrahydrofuran, 1,4-dioxane, n-propyl ether, n-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether;

In an inert gas atmosphere, add metal hydride or tertiary amine to the mixture of hexafluoroisopropyl alcohol and ether solvent, and react to obtain the first reaction liquid;

In an inert gas atmosphere, add phosphorus oxychloride to the first reaction liquid, heat and reflux the reaction to obtain a second reaction liquid;

Filter the second reaction liquid to obtain a filtrate;

The filtrate is fractionated, and the crude fraction containing tris(hexafluoroisopropyl)phosphate is collected;

Cooling and crystallization of the crude fraction;

Separate the crystals and mother liquor to obtain crystals;

Heat the crystal to obtain melted sweat, and collect tris(hexafluoroisopropyl) that meets the preset purity requirements.

2. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, characterized in that the temperature of mixing hexafluoroisopropyl alcohol and ether solvent is controlled at 0 ~ 30°C; The volume ratio of propanol to ether solvent is 1:1~5.

3. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, characterized in that the metal hydride is selected from one or more of the following substances: lithium hydride, sodium hydride, Potassium hydride, calcium hydride and lithium aluminum hydride; the tertiary amine is selected from one or more of the following substances: trimethylamine, triethylamine, pyridine, nitrogen, nitrogen-dimethylpyridine.

4. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, characterized in that, adding metal hydride or tertiary amine to the mixture of hexafluoroisopropyl alcohol and ether solvent, The reaction temperature is 0 ~ 30°C, the reaction time is 1 ~ 5 hours, and the effective molar ratio of metal hydride or tertiary amine and hexafluoroisopropanol is 0.9 ~ 1.2:1.

5. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, characterized in that: adding phosphorus oxychloride to the first reaction solution, and the step of heating and refluxing reaction is to add phosphorus oxychloride to the first reaction solution. Phosphorus oxychloride was added dropwise to the reaction solution. The temperature was controlled at 0 ~ 30°C during the dropwise addition. After the dropwise addition was completed, the temperature was controlled at 60 ~ 80°C. The mixed solution is heated to reflux for 1 to 5 hours; the molar ratio of the added phosphorus oxychloride to hexafluoroisopropanol is 0.3 to 0.4:1.

6. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, wherein the ether solvent is methyl tert-butyl ether;

The step is to fractionate the filtrate and collect the crude fraction containing tris (hexafluoroisopropyl) phosphate. The specific steps are: first fractionate the filtrate under normal pressure, collect the ether solvent, and then fractionate under reduced pressure to collect the crude fraction containing tris(hexafluoroisopropyl) phosphate. Crude fraction of propyl) phosphate.

7. The method for preparing tris(hexafluoroisopropyl)phosphate according to claim 1, wherein the step of cooling and crystallizing the collected crude fraction containing tris(hexafluoroisopropyl)phosphate is specifically: : The initial temperature of the crystallization environment is set to 20-25 °C. After constant temperature for 1-3 hours, the crystallization environment temperature decreases by 0.5-2°C every 15-45 minutes. The final temperature of the crystallization environment is set to 10-15 °C. The final constant temperature is 1 -3 hours.

8. The preparation method of tris(hexafluoroisopropyl) phosphate according to claim 1, characterized in that the step is to heat the crystals to obtain melted sweat, and collect tris(hexafluoroisopropyl) phosphate that meets the preset requirements. Among tris(hexafluoroisopropyl)phosphates, the preset requirement is that the purity of tris(hexafluoroisopropyl)phosphates should reach over 99%.

9. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, characterized in that,

When filtering the second reaction liquid in the step, use an ether solvent to clean the filter residue, and the obtained cleaning liquid is incorporated into the filtrate;

The mother liquor obtained in the step of separating the crystals and the mother liquor is added to the filtrate obtained in the step of filtering the second reaction liquid;

The step is to heat up the crystal to obtain melted sweat, collect the tris(hexafluoroisopropyl) phosphate that meets the preset purity requirements, collect the sweat that does not meet the preset purity requirements, and add it to 78-88° The fractions collected in the C range were crystallized together.

10. The preparation method of tris(hexafluoroisopropyl)phosphate according to claim 1, characterized in that, when the filtrate is fractionated in the step, the ether solvent is recovered and added to the step in an inert gas atmosphere. In the mixture obtained by mixing hexafluoroisopropyl alcohol and ether solvents.