阅读说明：本技术 全氟聚醚制备方法及其全氟聚醚 (Perfluoropolyether preparation method and perfluoropolyether thereof ) 是由 程亮 张�杰 于 2021-01-21 设计创作，主要内容包括：本发明公开了全氟聚醚制备方法及其全氟聚醚,制备方法包括：称取原料全氟烷基醇、全氟环氧烷烃、双金属氰化物催化剂；反应釜中先加入双金属氰化物催化剂,抽真空10-30分钟后充氮气,再加入全氟烷基醇以及第一次加入部分的全氟环氧烷烃,搅拌10-60分钟后加热至90-120℃,待反应釜内的压力有明显下降时,慢慢第二次加入剩余的全氟环氧烷烃,加入的速率以维持反应釜内的压力在0.5MPa；加完全氟环氧烷烃后,待反应釜内的压力恒定,反应结束；反应产物精制得到全氟聚醚。制备方法制得以下结构的化合物：本发明制备方法直接催化聚合制成、生产效率高、产率高、无有毒废弃物产生。(The invention discloses a preparation method of perfluoropolyether and the perfluoropolyether thereof, wherein the preparation method comprises the following steps: weighing raw materials of perfluoroalkyl alcohol, perfluoro alkylene oxide and double metal cyanide catalyst; adding a double metal cyanide catalyst into a reaction kettle, vacuumizing for 10-30 minutes, then filling nitrogen, then adding perfluoroalkyl alcohol and part of perfluoro alkylene oxide added for the first time, stirring for 10-60 minutes, heating to 90-120 ℃, slowly adding the rest perfluoro alkylene oxide for the second time when the pressure in the reaction kettle is obviously reduced, wherein the adding speed is used for maintaining the pressure in the reaction kettle at 0.5 MPa; after the perfluoro alkylene oxide is added, the reaction is finished when the pressure in the reaction kettle is constant; and refining the reaction product to obtain the perfluoropolyether. The preparation method prepares the compound with the following structure:)

1. A method for preparing perfluoropolyether, comprising: weighing raw materials of perfluoroalkyl alcohol, perfluoro alkylene oxide and double metal cyanide catalyst; adding a double metal cyanide catalyst into a reaction kettle, vacuumizing for 10-30 minutes, then filling nitrogen, then adding perfluoroalkyl alcohol and part of perfluoro alkylene oxide added for the first time, stirring for 10-60 minutes, heating to 90-120 ℃, slowly adding the rest perfluoro alkylene oxide for the second time when the pressure in the reaction kettle is obviously reduced, wherein the adding speed is used for maintaining the pressure in the reaction kettle at 0.5 MPa; after the perfluoro alkylene oxide is added, the reaction is finished when the pressure in the reaction kettle is constant; and refining the reaction product to obtain the perfluoropolyether.

2. The method for producing perfluoropolyether according to claim 1, wherein the perfluoroalkyl alcohol is the following compound: c₁～C₁₀The perfluoroalkyl alcohol of (1).

3. The process for preparing perfluoropolyether according to claim 1, wherein said perfluoroalkylene oxide is the following: c₂～C₂₂Of (a) a perfluoroalkylene oxide.

4. The method of claim 1, wherein the multimetal cyanide catalyst comprises: at least one double metal cyanide compound and at least one rare earth compound; the structure can be expressed as: m_a ¹[M²(CN)_b]_d·xM³(X)_c·zL¹；

In the formula, M¹Is Co³⁺、Ni²⁺、Zn²⁺、Fe²⁺、Fe³⁺、Ca²⁺、Mg²⁺、Cu²⁺、Cr³⁺、Al³⁺、Sn²⁺、Cd²⁺、Pb²⁺Or Sr²⁺；

M²Is Co³⁺、Fe³⁺、Fe²⁺、V⁴⁺、Mn²⁺、Ni²⁺Or Cr³⁺；

M³Is Zn²⁺；

X is F^-、Cl^-、Br^-、I^-、SO₄ ^2-、COO^-；

L¹Is a rare earth compound, is LaCl₃、PrCl₃、NdCl₃、NdBr₃、NdI₃、SmCl₃、EuCl₃、GdCl₃、DyCl₃、YbCl₃、CeCl₃Or Ce (NO)₃)₃，L¹The rare earth compound accounts for 1-85 wt% of the total amount of the double metal cyanide catalyst;

a. b, c and d are integers and satisfy charge balance; x and z are coefficients, and the ranges of x and z are both 1-10.

5. The process for preparing perfluoropolyether of claim 1 wherein the multimetal cyanide catalyst is added in an amount of 10 to 100ppm (based on product weight).

6. The process for preparing perfluoropolyether of claim 5 in which the multimetal cyanide catalyst is added in an amount of 10 to 50ppm by weight of product.

7. The process for preparing perfluoropolyethers according to claim 1, wherein the perfluoroalkyl alcohol is added in an amount of 50 to 100ppm (based on the weight of the product).

8. The process for producing perfluoropolyether according to claim 1, wherein the amount of the first addition of part of the perfluoroalkylene oxide is 10 to 20% by weight based on the starting material of the perfluoroalkylene oxide.

9. The process for producing perfluoropolyether according to claim 1, wherein the pressure in the reaction vessel is kept constant, which means that the pressure in the reaction vessel is kept constant or equal to one atmosphere.

10. A perfluoropolyether characterized in that the preparation process according to any one of claims 1 to 9 produces a compound of the following structure:

wherein m is 0-100, n is 0-100, and m and n are not zero at the same time; r₁Is C₁～C₁₀A perfluoroalkane; r₂Is fluorine or trifluoromethyl; r₃Is C₂～C₂₀Of a perfluoroalkane.

Technical Field

The invention belongs to the technical field of chemical industry, and particularly relates to a preparation method of perfluoropolyether and the perfluoropolyether.

Background

Perfluoropolyethers have unique physicochemical properties due to C-F chemical bonds, such as: the liquid material is tasteless, nontoxic, nonirritating, good in hand feeling, good in chemical stability, small in viscosity, good in film forming property and the like, belongs to a unique liquid material, and is widely applied to the fields of electronics, chemical industry, machinery, electricity, nuclear industry, aerospace and the like.

At present, perfluoropolyether is mainly prepared by photochemical oxidation polymerization of a special fluorine-containing monomer mixture and anionic polymerization of perfluoroepoxide, and is further treated by fluorine gas to form stable perfluoropolyether. The catalyst used comprises: transition metal higher fluorides, anhydrous hydrogen fluoride, and the like. These methods have certain disadvantages of low efficiency, low yield, toxic waste, and complex post-treatment. CN 106633023 discloses a two-step process for preparing perfluoropolyether using fluoroether oligomer as raw material. CN 107428929 discloses a method for producing perfluoropolyether acid fluorides, and stable perfluoropolyethers can be further produced by using the acid fluorides. CN 109970967 discloses a method for preparing single-end functional group perfluoropolyether by using fluoroalkane chain terminated double-end functional group perfluoropolyether. These publications have all worked around the preparation of perfluoropolyether processes and intermediates.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a perfluoropolyether with two blocked ends, aiming at the defects of the prior art.

The invention further provides a preparation method of perfluoropolyether, which is prepared by direct catalytic polymerization, has high production efficiency and high yield and does not generate toxic wastes.

The technical scheme adopted by the invention for solving the technical problems is as follows:

a method of preparing a perfluoropolyether, comprising: weighing raw materials of perfluoroalkyl alcohol, perfluoro alkylene oxide and double metal cyanide catalyst; adding a double metal cyanide catalyst into a reaction kettle, vacuumizing for 10-30 minutes, then filling nitrogen, then adding perfluoroalkyl alcohol and part of perfluoro alkylene oxide, stirring for 10-60 minutes, heating to 90-120 ℃, slowly adding the rest perfluoro alkylene oxide when the pressure in the reaction kettle is obviously reduced, and keeping the pressure in the reaction kettle at 0.5 MPa; after the addition is finished, the reaction is finished when the pressure in the reaction kettle is constant; and refining the reaction product to obtain the perfluoropolyether.

Further, in the method for preparing perfluoropolyether, the perfluoroalkyl alcohol is preferably the following compound: c₁～C₁₀The perfluoroalkyl alcohol of (1).

Further, in the method for preparing perfluoropolyether, the perfluoroalkylene oxide is preferably the following compound: c₂～C₂₂Of (b) a perfluoroalkylene oxideA hydrocarbon.

Further, in the method for preparing perfluoropolyether, the preferable multimetal cyanide catalyst comprises: at least one double metal cyanide compound and at least one rare earth compound; the structure can be expressed as:

M_a ¹[M²(CN)_b]_d·xM³(X)_c·zL¹；

in the formula, M¹Is Co³⁺、Ni²⁺、Zn²⁺、Fe²⁺、Fe³⁺、Ca²⁺、Mg²⁺、Cu²⁺、Cr³⁺、Al³⁺、Sn²⁺、Cd²⁺、Pb²⁺Or Sr^{2 +}；

M²Is Co³⁺、Fe³⁺、Fe²⁺、V⁴⁺、Mn²⁺、Ni²⁺Or Cr³⁺；

M³Is Zn²⁺；

X is F^-、Cl^-、Br^-、I^-、SO₄ ^2-、COO^-；

L¹Is a rare earth compound, is LaCl₃、PrCl₃、NdCl₃、NdBr₃、NdI₃、SmCl₃、EuCl₃、GdCl₃、DyCl₃、YbCl₃、CeCl₃Or Ce (NO)₃)₃，L¹The rare earth compound accounts for 1-85 wt% of the total amount of the double metal cyanide catalyst;

a. b, c and d are integers and satisfy charge balance; x and z are coefficients, and the ranges of x and z are both 1-10.

Further, in the method for preparing perfluoropolyether, the amount of the multimetal cyanide catalyst added is preferably 10 to 100ppm (based on the weight of the product).

Further, in the method for preparing perfluoropolyether, the amount of the multimetal cyanide catalyst added is preferably 10 to 50ppm (based on the weight of the product).

Further, in the method for preparing perfluoropolyether, the addition amount of the perfluoroalkyl alcohol is preferably 50 to 100ppm (based on the weight of the product).

Further, in the method for preparing perfluoropolyether, it is preferable that the amount of the first-added part of perfluoroalkylene oxide is 10 to 20% by weight of the starting material of perfluoroalkylene oxide.

Further, in the method for preparing perfluoropolyether, preferably, the pressure in the reaction kettle is constant, which means that the pressure in the reaction kettle is kept constant or equal to one atmosphere.

A perfluoropolyether that is a compound of the structure:

wherein m is 0 to 100, n is 0 to 100, m and n are not zero at the same time, and R is₁Is C₁～C₁₀A perfluoroalkane; r₂Is fluorine or trifluoromethyl; r₃Is C₂～C₂₀Of a perfluoroalkane.

In the perfluoropolyether, it is preferable that m is 0 to 20, n is 0 to 20, and m and n are not zero at the same time.

Further, in the perfluoropolyether, it is preferable that R is₁Is C₁～C₁₀A perfluoroalkane; or/and R₂Is fluorine or trifluoromethyl; or/and R₃Is C₂～C₂₀Of a perfluoroalkane.

The preparation method of the invention uses a multi-metal cyanide catalyst to directly catalyze the polymerization of the perfluoroalkylene oxide to obtain the double-end-capped perfluoropolyether. The used catalyst does not contain fluorine, so that no environmental pollution exists; the catalyst has high catalytic efficiency, low dosage and good stability, and the generated product can be capped without adding extra reagents; the preparation method has the advantages of simple preparation process, no solvent, easy operation and control, continuous production, high production efficiency, low production cost, no need of filtering, washing and other process steps and addition of auxiliary ingredients, electricity and water conservation, and suitability for industrial production. Simple and safe operation and industrial popularization value.

The perfluoropolyether has the characteristics of heat resistance, oxidation resistance, radiation resistance, corrosion resistance, incombustibility and the like, and can be used as a lubricant in the advanced fields of military, aerospace, nuclear industry and the like.

Detailed Description

In order to more clearly understand the technical features, objects, and effects of the present invention, specific embodiments of the present invention will now be described in detail.

A method of preparing a perfluoropolyether, comprising: weighing raw materials of perfluoroalkyl alcohol, perfluoro alkylene oxide and double metal cyanide catalyst; adding a double metal cyanide catalyst into a reaction kettle, vacuumizing for 10-30 minutes, then filling nitrogen, then adding perfluoroalkyl alcohol and part of perfluoro alkylene oxide, stirring for 10-60 minutes, heating to 90-120 ℃, slowly adding the rest perfluoro alkylene oxide when the pressure in the reaction kettle is obviously reduced, and keeping the pressure in the reaction kettle at 0.5 MPa; after the addition is finished, the reaction is finished when the pressure in the reaction kettle is constant; and refining the reaction product to obtain the perfluoropolyether. Further, in the method for preparing perfluoropolyether, the perfluoroalkyl alcohol is preferably the following compound: c₁～C₁₀The perfluoroalkyl alcohol of (1).

Further, in the method for preparing perfluoropolyether, the perfluoroalkylene oxide is preferably the following compound: c₂～C₂₂Of (a) a perfluoroalkylene oxide.

Further, in the method for preparing perfluoropolyether, the preferable multimetal cyanide catalyst comprises: at least one double metal cyanide compound and at least one rare earth compound; the structure can be expressed as: m_a ¹[M²(CN)_b]_d·xM³(X)_c·zL¹；

In the formula, M¹Is Co³⁺、Ni²⁺、Zn²⁺、Fe²⁺、Fe³⁺、Ca²⁺、Mg²⁺、Cu²⁺、Cr³⁺、Al³⁺、Sn²⁺、Cd²⁺、Pb²⁺Or Sr^{2 +}(ii) a Zn is preferred²⁺、Fe²⁺、Fe³⁺、Ni²⁺、Co³⁺More preferably Zn²⁺；

M²Is Co³⁺、Fe³⁺、Fe²⁺、V⁴⁺、Mn²⁺、Ni²⁺Or Cr³⁺(ii) a Preferably Co³⁺、Fe²⁺、Fe³⁺；

M³Is Zn²⁺；

X is F^-、Cl^-、Br^-、I^-、SO₄ ^2-、COO^-(ii) a Preferably Cl^-；

L¹Is a rare earth compound, is LaCl₃、PrCl₃、NdCl₃、NdBr₃、NdI₃、SmCl₃、EuCl₃、GdCl₃、DyCl₃、YbCl₃、CeCl₃Or Ce (NO)₃)₃Preferably CeCl₃、LaCl₃，L¹The rare earth compound accounts for 1-85 wt% of the total amount of the double metal cyanide catalyst;

a. b, c and d are integers and satisfy charge balance; x and z are coefficients, and the ranges of x and z are both 1-10.

Further, in the method for preparing perfluoropolyether, the amount of the multimetal cyanide catalyst added is preferably 10 to 100ppm (based on the weight of the product).

Further, in the method for preparing perfluoropolyether, the amount of the multimetal cyanide catalyst added is preferably 10 to 50ppm (based on the weight of the product).

Further, in the method for preparing perfluoropolyether, the addition amount of the perfluoroalkyl alcohol is preferably 50 to 100ppm (based on the weight of the product).

Further, in the method for preparing perfluoropolyether, it is preferable that the amount of the first-added part of perfluoroalkylene oxide is 10 to 20% by weight of the starting material of perfluoroalkylene oxide.

Further, in the method for preparing perfluoropolyether, preferably, the pressure in the reaction kettle is constant, which means that the pressure in the reaction kettle is kept constant or equal to one atmosphere.

A perfluoropolyether that is a compound of the structure:

wherein m is 0 to 100, n is 0 to 100, m and n are not zero at the same time, and R is₁Is C₁～C₁₀A perfluoroalkane; r₂Is fluorine or trifluoromethyl; r₃Is C₂～C₂₀Of a perfluoroalkane.

In the perfluoropolyether, it is preferable that m is 0 to 20, n is 0 to 20, and m and n are not zero at the same time.

Further, in the perfluoropolyether, it is preferable that R is₁Is C₁～C₁₀A perfluoroalkane; or/and R₂Is fluorine or trifluoromethyl; or/and R₃Is C₂～C₂₀Of a perfluoroalkane.

The following is detailed by specific examples:

example 1, a perfluoropolyether, a compound of the following structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 10 mg of multimetal cyanide catalyst Co [ Fe (CN)₃]₃·2ZnCl₂·3LaCl₃Vacuumizing for 10 minutes, replacing the reaction kettle with nitrogen for three times, adding 20 mg of perfluoromethanol, 14.5 g of perfluoroethylene oxide and 12.6 g of perfluoropentane into the reaction kettle under the condition of nitrogen, stirring for 10 minutes, heating to 90 ℃, adding 140 g of perfluoroethylene oxide and 120 g of perfluoropentane oxide at the rate of 0.3 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at 0.5MPa, continuing aging for 1 hour, and ending the reaction. The reaction product was filtered to give the product of example 1.

Example 2, a perfluoropolyether, a compound of the following structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 50 mg of multimetal cyanide catalyst Ni [ Fe (CN)₃]₂·5ZnCl₂·2CeCl₃Vacuumizing for 30 minutes, replacing the mixture with nitrogen for three times, adding 100 mg of perfluorobutanol, 20 g of perfluoropropylene oxide and 10 g of perfluorodecane into a reaction kettle under the action of nitrogen, stirring for 60 minutes, heating to 120 ℃, adding 180 g of perfluoropropylene oxide and 170 g of perfluorodecane oxide at the rate of 0.5 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at one atmospheric pressure, continuing aging for 1 hour, and finishing the reaction. The reaction product was filtered to give the product of example 2.

Example 3, a perfluoropolyether, a compound of the following structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 62 mg of multimetal cyanide catalyst Sr [ Fe (CN)₃]₂·6ZnCl₂·3NdBr₃Vacuumizing for 20 minutes, replacing the reaction kettle with nitrogen for three times, adding 100 mg of perfluoroisohexanol, 25 g of perfluoroethylene oxide and 10 g of perfluoroheptane oxide into the reaction kettle under the nitrogen atmosphere, stirring for 50 minutes, heating to 100 ℃, adding 480 g of perfluoroethylene oxide and 120 g of perfluoroheptane oxide at the rate of 0.6 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at 0.2MPa, and continuing aging for 1 hour to finish the reaction. The reaction product was filtered to give the product of example 3.

Example 4, a perfluoropolyether, a compound of the following structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 70 mg of multimetal cyanide catalyst Zn [ Fe (CN)₂]₂·ZnCl₂·9NdI₃Vacuumizing for 20 minutes, replacing the reaction kettle with nitrogen for three times, adding 120 mg of perfluoro-n-hexanol, 10 g of perfluoro-propylene oxide and 5 g of perfluoro-hexane oxide into the reaction kettle under the nitrogen, stirring for 30 minutes, heating to 90 ℃, adding 140 g of perfluoro-propylene oxide and 150 g of perfluoro-hexane oxide at the rate of 0.8 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at 0.6MPa, continuing aging for 2 hours, and ending the reaction. The reaction product was filtered to give the product of example 4.

Example 5, a perfluoropolyether, a compound of the following structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 20 mg of multimetal cyanide catalyst Cu [ Cr (CN)₃]₂·2ZnCl₂·DyCl₃Vacuumizing for 20 minutes, replacing the reaction kettle with nitrogen for three times, adding 50 mg of perfluoroisooctanol and 19 g of perfluorobutylene oxide into the reaction kettle under the nitrogen, stirring for 40 minutes, heating to 120 ℃, adding 100 g of perfluorobutylene oxide at the rate of 0.5 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at one atmosphere, continuing aging for 1.2 hours, and finishing the reaction. The reaction product was filtered to give the product of example 5.

Example 6, a perfluoropolyether, is a compound of the following structure:

the preparation method of the perfluoropolyether comprises the following steps: to 250mL of high pressureThe autoclave was charged with 30 mg of multimetal cyanide catalyst Al [ Sn (CN)₂]₃·4ZnCl₂·DyCl₃Vacuumizing for 30 minutes, replacing the reaction kettle with nitrogen for three times, adding 60 mg of perfluoro-n-decanol, 22 g of perfluorobutylene oxide and 13 g of perfluoropropylene oxide into the reaction kettle under the condition of nitrogen, stirring for 30 minutes, heating to 120 ℃, adding 140 g of perfluorobutylene oxide and 110 g of perfluoropropylene oxide at the rate of 0.6 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at 1MPa, and continuing aging for 1.5 hours to finish the reaction. The reaction product was filtered to give the product of example 6.

Example 7, a perfluoropolyether, a compound of the structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 40 Mg multimetal cyanide catalyst Mg [ Sn (CN)₂]₂·2ZnBr ₂·GdCl₃Vacuumizing for 20 minutes, replacing the reaction kettle with nitrogen for three times, adding 90 mg of perfluoroisooctanol and 19 g of perfluoropropylene oxide into the reaction kettle under the nitrogen, stirring for 60 minutes, heating to 110 ℃, adding 90 g of perfluoropropylene oxide at the rate of 0.7 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at one atmosphere, continuing aging for 1 hour, and finishing the reaction. The reaction product was filtered to give the product of example 7.

Example 8, a perfluoropolyether, a compound of the structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 10 Mg multimetal cyanide catalyst Mg [ V (CN)₄]₂·ZnSO₄·GdCl₃Vacuum pumping for 10 min, replacing three times with nitrogen, under nitrogen, inAdding 30 mg of perfluoro-n-propanol, 25 g of perfluoro-ethylene oxide and 15 g of perfluoro-propylene oxide into a reaction kettle, stirring for 20 minutes, heating to 100 ℃, adding 200 g of perfluoro-ethylene oxide and 150 g of perfluoro-propylene oxide at the rate of 1.0 g/min when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at one atmospheric pressure, continuing aging for 1 hour, and finishing the reaction. The reaction product was filtered to give the product of example 8.

Example 9, a perfluoropolyether, a compound of the structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was charged 45 mg of multimetal cyanide catalyst Co [ V (CN)₄]₃·9ZnSO₄·3LaCl₃Vacuumizing for 10 minutes, replacing the reaction kettle with nitrogen for three times, adding 100 mg of perfluoro-n-hexanol and 24 g of perfluoro-butylene oxide into the reaction kettle under the nitrogen, stirring for 50 minutes, heating to 90 ℃, adding 190 g of perfluoro-butylene oxide at the speed of 1.0 g/minute when the pressure in the reaction kettle is obviously reduced, maintaining the pressure in the reaction kettle at one atmosphere, continuing aging for 1.5 hours, and finishing the reaction. The reaction product was filtered to give the product of example 9.

Example 10, a perfluoropolyether, is a compound of the structure:

the preparation method of the perfluoropolyether comprises the following steps: to a 250mL autoclave was added 93 mg of multimetal cyanide catalyst Co [ Mn (CN)₂]₃·5Zn(COO)₂·9LaCl₃Vacuumizing for 30 minutes, replacing the mixture with nitrogen for three times, adding 200 mg of perfluoro-n-heptanol, 27 g of perfluorobutylene oxide and 20 g of perfluoroethylene oxide into a reaction kettle under the condition of nitrogen, stirring for 60 minutes, heating to 110 ℃, and keeping the pressure in the reaction kettle to be obviousWhen the reaction temperature decreases, 420 g of perfluorobutylene oxide and 100 g of perfluoroethylene oxide are added at a rate of 1.0 g/min, the pressure in the reaction kettle is maintained at one atmosphere, and aging is continued for 1.5 hours, so that the reaction is finished. The reaction product was filtered to give the product of example 10.

1. Nuclear magnetic analysis

The products of examples 1-10 were subjected to nuclear magnetic detection and the reaction products¹⁹F-NMR analysis results: a has a chemical shift of-75.97X 10^-6(ii) a Chemical shift of b is-145.67X 10^-6(ii) a chemical shift of c is-80.77X 10^-6(ii) a Chemical shift of d is-50.19X 10^-6。

2. Analysis of fluorine content

From nuclear magnetism and fluorine content data analysis, the process of the invention obtains the target product. The fluorine content increased with increasing perfluoropolyether molecular weight, from 73.8% to 76.7%, consistent with the theoretical trend, further illustrating the advancement of the process of the present invention.

3. Molecular weight distribution analysis

	Molecular weight distribution (Mw/Mn)
		Example 1	1.032
Example 2	1.035
		Example 3	1.026
Example 4	1.033
		Example 5	1.042
Example 6	1.030
		Example 7	1.032
Example 8	1.027
		Example 9	1.029
Example 10	1.048

Through GPC analysis, the molecular weight distribution of the product of the invention is close to 1, and the molecular weight distribution of the product is narrow, which shows the advancement of the process.