Synthesis method of perfluoro-n-propyl vinyl ether

Abstract

The invention discloses a synthesis method of perfluoro-n-propyl vinyl ether, and in the method, an inorganic metal salt catalyst has a strong capability of being combined with fluorine, and can be combined with acyl fluoride of a dimer to form a transition state in a reaction process, so that the acyl fluoride becomes a leaving group after the temperature is raised, and the leaving group is removed. In order to reduce the content of hydrogen-containing ether generated in the synthesis process of the perfluoro-n-propyl vinyl ether, the embodiment of the invention further provides a method for synthesizing the perfluoro-n-propyl vinyl ether by catalyzing the decarboxylation reaction of hexafluoropropylene oxide dimer carboxylic acid by using transition metal Lewis acid. A hexafluoropropylene oxide dimer is used as a raw material and is catalyzed by transition metal salt to generate a decarboxylation reaction to generate the perfluoro-n-propyl vinyl ether, the reaction can effectively avoid the defect that hydrogen-containing ether byproducts are easy to generate in the synthesis method, and the separation method is simplified.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a method for synthesizing perfluoro n-propyl vinyl ether. Background Art

[0002] Perfluoro-n-propyl vinyl ether is a copolymer monomer of fluorinated vinyl ether. It can be used as a copolymer or modified monomer in polymerization to change certain properties of fluoropolymers, such as low temperature resistance, solvent resistance, toughness, tear resistance, and adhesion to substrates. It will not change the original corrosion resistance and aging resistance of the polymer and has a wide range of applications.

[0003] In the related art, the synthesis methods of perfluoro n-propyl vinyl ether mainly include: direct pyrolysis method, catalytic pyrolysis method, fluorine-containing building block method and reduction method. Among them, the direct pyrolysis method is simple to operate, has a high yield, is suitable for industrial production, and is a common preparation method. The direct pyrolysis method generally uses hexafluoropropylene oxide as a raw material, self-polymerizes to generate an acyl fluoride intermediate, which is hydrolyzed into a salt by a metal salt compound, and then thermally cracked, decarboxylated and metal fluoride is used to obtain the structure of the olefin ether. Among them, decarboxylation is the key step in the entire process.

[0004] The decarboxylation process will produce a certain amount of main by-product hydrogenated ether, which will have an adverse effect on the production of downstream products. Chain transfer may occur, causing the molecular weight of the polymer obtained by polymerization to decrease, thereby affecting the quality of the polymer. Therefore, the hydrogenated ether must be removed. Summary of the invention

[0005] The embodiment of the present application provides a method for synthesizing perfluoro-n-propyl vinyl ether, in which hexafluoropropylene oxide dimer is used as a raw material and a decarboxylation reaction is carried out under the catalysis of an inorganic metal salt to generate perfluoro-n-propyl vinyl ether. This method can effectively avoid the disadvantage of the synthesis method of the related art that hydrogen-containing ether by-products are easily produced, and simplify the separation method.

[0006] The present invention provides a method for synthesizing perfluoro n-propyl vinyl ether, comprising:

[0007] The organic solvent, the inorganic metal salt catalyst and the hexafluoropropylene oxide dimer are co-heated to a first preset temperature and maintained at the first preset temperature for a first preset time to perform a decarboxylation reaction to obtain perfluoro-n-propyl vinyl ether.

[0008] In some embodiments, the step of heating the organic solvent, the inorganic metal salt catalyst and the hexafluoropropylene oxide dimer to a first preset temperature and maintaining the first preset temperature for a first preset time comprises:

[0009] In an organic solvent and an inorganic metal salt catalyst, hexafluoropropylene oxide dimer is added dropwise, and after the addition is completed, the mixture is stabilized for a second preset time to obtain a mixture;

[0010] The mixture is heated to a first preset temperature and maintained at the first preset temperature for a first preset time to obtain perfluoro-n-propyl vinyl ether.

[0011] In some embodiments, before the step of adding hexafluoropropylene oxide dimer dropwise to the organic solvent and the inorganic metal salt catalyst, the method further comprises:

[0012] The organic solvent and the inorganic metal salt catalyst are cooled to a second preset temperature.

[0013] In some embodiments, the mass ratio of the hexafluoropropylene oxide dimer, the organic solvent and the inorganic metal salt catalyst is 1:(1-2):(0.01-1).

[0014] In some embodiments, the inorganic metal salt catalyst includes at least one of CrCl3, SbCl3, FeCl3, and CaCl2.

[0015] In some embodiments, the organic solvent includes at least one of methanol, ethanol, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, acetonitrile, propionitrile, and dimethyl sulfoxide.

[0016] In some embodiments, the first preset temperature is greater than 60°C and less than 150°C.

[0017] In some embodiments, the first preset time is 1-6 hours.

[0018] In some embodiments, the second preset time is 0.5h.

[0019] In some embodiments, the second preset temperature is greater than 5°C and less than 30°C.

[0020] The present invention provides a method for synthesizing perfluoro n-propyl vinyl ether, in which, since the inorganic metal salt catalyst has a strong ability to bind to fluorine, it can be combined with the acyl fluoride of the dimer to form a transition state during the reaction, and after the temperature is increased, it can be made into a leaving group, thereby removing it. In order to reduce the content of hydrogen-containing ethers generated during the synthesis of perfluoro n-propyl vinyl ether, the embodiment of the present application further proposes a method for synthesizing perfluoro n-propyl vinyl ether by using a transition metal Lewis acid to catalyze the decarboxylation reaction of hexafluoropropylene oxide dimer carboxylic acid. The reaction of generating perfluoro n-propyl vinyl ether by decarboxylation reaction of hexafluoropropylene oxide dimer as a raw material and catalyzed by a transition metal salt can effectively avoid the disadvantage of the above-mentioned synthesis method that hydrogen-containing ether by-products are easily produced, and simplify the separation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1A flow chart of a method for synthesizing perfluoro-n-propyl vinyl ether provided according to some embodiments is exemplified;

[0022] Figure 2 A flow chart of another method for synthesizing perfluoro-n-propyl vinyl ether provided according to some embodiments is exemplified. DETAILED DESCRIPTION

[0023] In order to better understand the above technical solution, the technical solution of the present application is described in detail below through specific implementation methods.

[0024] Figure 1 The flowchart of a method for synthesizing perfluoro-n-propyl vinyl ether provided in accordance with some embodiments is exemplified. The embodiment of the present application provides a method for synthesizing perfluoro-n-propyl vinyl ether. The method comprises S100.

[0025] The organic solvent, the inorganic metal salt catalyst and the hexafluoropropylene oxide dimer are co-heated to a first preset temperature and maintained at the first preset temperature for a first preset time to perform a decarboxylation reaction to obtain perfluoro-n-propyl vinyl ether.

[0026] In the present embodiment, hexafluoropropylene oxide dimer, inorganic metal salt catalyst and organic solvent are heated together under anhydrous conditions and maintained for a certain period of time to generate perfluoro-n-propyl vinyl ether by decarboxylation (-COOH) reaction.

[0027] Specifically, the following reaction occurs:

[0028]

[0029] Among them, M n+ Cl n It is an inorganic metal salt catalyst.

[0030] Since the inorganic metal salt catalyst has a strong ability to bind to fluorine, it can be combined with the acyl fluoride of the dimer to form a transition state during the reaction, and after the temperature is increased, it can be made into a leaving group, thereby removing it. In order to reduce the content of hydrogen-containing ether generated during the synthesis of perfluoro-n-propyl vinyl ether, the embodiment of the present application proposes a method for synthesizing perfluoro-n-propyl vinyl ether by decarboxylating hexafluoropropylene oxide dimer carboxylic acid using a transition metal Lewis acid. The reaction of generating perfluoro-n-propyl vinyl ether by decarboxylating hexafluoropropylene oxide dimer as a raw material through a transition metal salt catalysis can effectively avoid the disadvantage of the above-mentioned synthesis method that hydrogen-containing ether by-products are easily produced, and simplify the separation method.

[0031] In some embodiments, the mass ratio of the hexafluoropropylene oxide dimer, the organic solvent and the inorganic metal salt catalyst is 1:(1-2):(0.01-1).

[0032] In some embodiments, the inorganic metal salt catalyst includes at least one of CrCl3, SbCl3, FeCl3, and CaCl2. In some embodiments, the inorganic metal salt catalyst is CrCl3. When the inorganic metal salt catalyst is CrCl3, the yield of perfluoro n-propyl vinyl ether is 92%. For details, please refer to Example 8 below.

[0033] In some embodiments, the organic solvent includes at least one of methanol, ethanol, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, acetonitrile, propionitrile, and dimethyl sulfoxide.

[0034] In some embodiments, Figure 2 A flowchart of another method for synthesizing perfluoro n-propyl vinyl ether provided according to some embodiments is exemplified. The steps of heating the organic solvent, the inorganic metal salt catalyst and the hexafluoropropylene oxide dimer to a first preset temperature and maintaining the first preset temperature for a first preset time include S101-S102.

[0035] S101. Add hexafluoropropylene oxide dimer dropwise to an organic solvent and an inorganic metal salt catalyst, and stabilize for a second preset time after the dropwise addition is completed to obtain a mixture.

[0036] In this embodiment, the second preset time is stabilized after the hexafluoropropylene oxide dimer is added dropwise, so that the hexafluoropropylene oxide dimer and the inorganic metal salt catalyst are fully combined. In some embodiments, the second preset time is 0.5h, and stabilization for 0.5h is conducive to the subsequent reaction.

[0037] In some embodiments, before the step of adding hexafluoropropylene oxide dimer to the organic solvent and the inorganic metal salt catalyst, the method further comprises: cooling the organic solvent and the inorganic metal salt catalyst to a second preset temperature. In some embodiments, the second preset temperature is greater than 5°C and less than 30°C.

[0038] In this embodiment, when the second preset temperature is greater than or equal to 30° C., the raw materials may escape, thereby increasing the pressure in the reaction container and causing the risk of material rushing. When the second preset temperature is less than or equal to 5° C., the subsequent reaction rate may be slow or the reaction may be incomplete.

[0039] In some embodiments, hexafluoropropylene oxide dimer is uniformly added dropwise to an organic solvent and an inorganic metal salt catalyst within 0.5-2 hours.

[0040] S102, heating the mixture to a first preset temperature, and maintaining the first preset temperature for a first preset time to obtain perfluoro-n-propyl vinyl ether.

[0041] In some embodiments, the first preset temperature is greater than 60° C. and less than 150° C. When the first preset temperature is greater than or equal to 150° C., the solvent will boil and generate a large amount of foam, and when the first preset temperature is less than or equal to 60° C., no reaction will occur.

[0042] In some embodiments, the first preset time is 1-6 hours. The first preset time is specifically determined by the type of inorganic metal salt catalyst, the amount of feed and the first preset temperature. The degree of reaction can be determined by gas chromatography, and after the decarboxylation reaction is complete, the reactants are condensed and collected.

[0043] The method in the examples of the present application is simple to operate and has mild reaction conditions. The perfluoro-n-propyl vinyl ether synthesized by this method has a higher yield.

[0044] Embodiment 1:

[0045] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether and 3g of anhydrous CrCl3 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the addition is completed, keep it for 0.5h, slowly raise the temperature to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the obtained 232.4g product is identified by gas chromatography, and its content is 95%. The yield of perfluoro n-propyl vinyl ether is calculated to be 83%.

[0046] Comparative Example 1:

[0047] In a strictly dried 1000ml three-necked glass flask, 400ml diethylene glycol dimethyl ether and 3g anhydrous CrCl3 were added at 5°C, stirring was started, and 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% was slowly dripped in for 1h. After the dropwise addition was completed, the temperature was kept for 0.5h, and the temperature was slowly raised to 90°C. The low-boiling product generated by the reaction was collected in a collection bottle through a condenser tube and stored at low temperature. After the reaction was completed, the obtained 215.4g product was identified by gas chromatography, and its content was 93%. The yield of perfluoro n-propyl vinyl ether was calculated to be 75%. The dripping temperature of dripping hexafluoropropylene oxide was reduced in this comparative example, resulting in a decrease in yield.

[0048] Comparative Example 2:

[0049] In a strictly dried 1000ml three-necked glass flask, 400ml diethylene glycol dimethyl ether and 3g anhydrous CrCl3 were added at 30°C, stirring was started, 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% was slowly added dropwise for 1h, after completion of the dropwise addition, the mixture was kept for 0.5h, and the temperature was slowly raised to 90°C. The low-boiling product generated by the reaction was collected in a collection bottle through a condenser tube and stored at low temperature. After the reaction was completed, the obtained 277.8g product was identified by gas chromatography, and its content was 74%. The yield of perfluoro n-propyl vinyl ether was calculated to be 77%. In this comparative example, due to the increased dropping temperature, a part of the raw materials escaped, resulting in a decrease in yield.

[0050] Comparative Example 3:

[0051] In a strictly dry 1000ml three-necked glass flask, 400ml diethylene glycol dimethyl ether and 3g anhydrous CrCl3 were added at room temperature, stirring was started, 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% was slowly added dropwise for 1h, after completion of the dropwise addition, the mixture was kept for 0.5h, and the mixture was slowly warmed to 150°C, and the low-boiling product generated by the reaction was collected in a collecting bottle and stored at low temperature by a condensing tube, and after the reaction was completed, the 304g product obtained was identified by gas chromatography, and its content was 46%, and the yield of perfluoro n-propyl vinyl ether was 52% after calculation. The temperature of the reaction decarboxylation was raised in this comparative example, resulting in serious bubbling of the raw materials during the experiment, and some raw materials escaped from the reaction vessel and entered the collecting vessel.

[0052] Comparative Example 4:

[0053] In a strictly dry 1000ml three-necked glass flask, 400ml diethylene glycol dimethyl ether and 3g anhydrous CrCl3 were added at room temperature, stirring was started, 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% was slowly added dropwise for 1h, after completion of the dropwise addition, the mixture was kept for 0.5h, and the mixture was slowly warmed to 60°C. The low-boiling product generated by the reaction was collected in a collecting bottle and stored at low temperature by a condensing tube. After the reaction was completed, the 16g product obtained was identified by gas chromatography, and its content was 28%, and the yield of perfluoro n-propyl vinyl ether was calculated to be 0.016%. The temperature of the reaction decarboxylation was reduced in this comparative example, resulting in the hexafluoropropylene dimer that was almost unreacted and collected in the experimental process, which was mostly dispersed.

[0054] Comparative Example 5:

[0055] In a strictly dried 1000ml three-necked glass flask, add 350ml diethylene glycol dimethyl ether and 3g anhydrous CrCl3 at room temperature, start stirring, slowly drip 347.3g (1mol) hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1:0.01. After the dropwise addition is completed, keep it for 0.5h, slowly heat it to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the obtained 228.4g product is identified by gas chromatography, and its content is 94%. After calculation, the yield of perfluoro n-propyl vinyl ether is 80%. In this comparative example, the mass ratio of organic solvent to hexafluoropropylene oxide dimer is 1:1, which reduces the proportion of solvent use and slightly reduces the yield.

[0056] Comparative Example 6:

[0057] In a strictly dried 1000ml three-necked glass flask, add 700ml diethylene glycol dimethyl ether and 3g anhydrous CrCl3 at room temperature, start stirring, slowly drip 347.3g (1mol) hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.9:0.01. After the dropwise addition is completed, keep it for 0.5h, slowly heat it to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the obtained 210.7g product is identified by gas chromatography, and its content is 91%. The yield of perfluoro n-propyl vinyl ether is 72% after calculation. In this comparative example, the mass ratio of organic solvent to hexafluoropropylene oxide dimer is 1:1.9, which increases the proportion of solvent use, and the yield and content are significantly reduced.

[0058] Comparative Example 7:

[0059] In a strictly dried 500ml three-necked glass flask, add 200ml diethylene glycol dimethyl ether and 178.8g anhydrous CrCl3 at room temperature, start stirring, slowly drip 178.8g (0.5mol) hexafluoropropylene oxide dimer with a content of 95% for 1h, in which case the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.05:1, after the dropwise addition is completed, keep for 0.5h, slowly heat up to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store at low temperature, after the reaction is completed, the obtained 118g product is identified by gas chromatography, and its content is 98%, and the yield of perfluoro n-propyl vinyl ether is calculated to be 87%. In this comparative example, the proportion of catalyst used is increased, and the yield is slightly increased, but the cost is higher.

[0060] Embodiment 2:

[0061] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether and 3g of anhydrous SbCl3 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the addition is completed, keep it for 0.5h, slowly raise the temperature to 90℃, collect the low-boiling point products generated by the reaction into a collection bottle through a condenser and store them at low temperature. After the reaction is completed, the obtained 249.7g product is identified by gas chromatography, and its content is 98%. The yield of perfluoro n-propyl vinyl ether is calculated to be 92%.

[0062] Embodiment three:

[0063] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether and 3g of anhydrous FeCl3 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the addition is completed, keep it for 0.5h, slowly heat it to 90℃, collect the low-boiling point products generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the obtained 232.8g product is identified by gas chromatography, and its content is 72%. The yield of perfluoro n-propyl vinyl ether is calculated to be 63%.

[0064] Compared with Example 1, in Example 5, FeCl 3 is used as a catalyst, and the catalytic effect is poor, which is due to the poor binding ability of FeCl 3 and F.

[0065] Embodiment 4:

[0066] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether and 3g of anhydrous CaCl2 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the addition is completed, keep it for 0.5h, slowly raise the temperature to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the 164.3g product obtained is identified by gas chromatography, and its content is 68%. The yield of perfluoro n-propyl vinyl ether is calculated to be 42%.

[0067] Compared with Example 1, in Example 5, CaCl2 is used as a catalyst, and the catalytic effect is poor, which is due to the poor binding ability of CaCl2 with F.

[0068] Embodiment five:

[0069] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether, 1.5g of anhydrous CrCl3 and 1.5g of anhydrous SbCl3 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the dropwise addition is completed, keep it for 0.5h, slowly raise the temperature to 90℃, collect the low-boiling point products generated by the reaction into a collection bottle through a condenser and store them at low temperature. After the reaction is completed, the obtained 249.4g product has a content of 96% after identification by gas chromatography. The yield of perfluoro n-propyl vinyl ether is calculated to be 90%.

[0070] Embodiment six:

[0071] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether, 1.5g of anhydrous CrCl3 and 1.5g of anhydrous FeCl3 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the dropwise addition is completed, keep it for 0.5h, slowly heat it to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the obtained 256.3g product has a content of 83% after identification by gas chromatography. The yield of perfluoro n-propyl vinyl ether is calculated to be 80%.

[0072] Embodiment seven:

[0073] In a strictly dried 1000ml three-necked glass flask, add 400ml of diethylene glycol dimethyl ether, 1.5g of anhydrous CrCl3 and 1.5g of anhydrous CaCl2 at room temperature, start stirring, and slowly drop 347.3g (1mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.08:0.01. After the dropwise addition is completed, keep it for 0.5h, slowly raise the temperature to 90℃, collect the low boiling point product generated by the reaction into a collection bottle through a condenser and store it at low temperature. After the reaction is completed, the obtained 250.5g product has a content of 86% after gas chromatography identification, and the yield of perfluoro n-propyl vinyl ether is calculated to be 81%.

[0074] Embodiment eight:

[0075] In a strictly dried 5000ml stainless steel reactor, add 2000ml diethylene glycol dimethyl ether and 17g anhydrous CrCl3 at room temperature, start stirring, and slowly drop 1736.5g (5mol) of hexafluoropropylene oxide dimer with a content of 95% for 1 hour. In this case, the mass ratio of hexafluoropropylene oxide dimer, organic solvent and inorganic metal salt catalyst is 1:1.14:0.01. After the addition is completed, keep it for 0.5h, slowly raise the temperature to 90℃, collect the low boiling point products generated by the reaction into the collection kettle through a condenser and store them at low temperature. After the reaction is completed, the obtained 1261.44g product is identified by gas chromatography, and its content is 97%. The yield of perfluoro n-propyl vinyl ether is calculated to be 92%.

[0076] In summary, the present invention provides a method for synthesizing perfluoro n-propyl vinyl ether, in which, since the inorganic metal salt catalyst has a strong ability to bind to fluorine, it can be combined with the acyl fluoride of the dimer to form a transition state during the reaction, and after the temperature is increased, it can be made into a leaving group, thereby removing it. In order to reduce the content of hydrogen-containing ethers generated during the synthesis of perfluoro n-propyl vinyl ether, the embodiment of the present application proposes a method for synthesizing perfluoro n-propyl vinyl ether by decarboxylating hexafluoropropylene oxide dimer carboxylic acid using a transition metal Lewis acid. The reaction of generating perfluoro n-propyl vinyl ether by decarboxylating hexafluoropropylene oxide dimer as a raw material through a transition metal salt catalysis can effectively avoid the disadvantage of easily generating hydrogen-containing ether by-products in the above-mentioned synthesis method, and simplify the separation method.

[0077] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed. The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application. The above are only preferred implementation methods of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A method for synthesizing perfluoro n-propyl vinyl ether, characterized in that: include: The organic solvent, the inorganic metal salt catalyst and the hexafluoropropylene oxide dimer are co-heated to a first preset temperature and maintained at the first preset temperature for a first preset time to perform a decarboxylation reaction to obtain perfluoro-n-propyl vinyl ether.

2. The method according to claim 1, characterized in that The step of heating the organic solvent, the inorganic metal salt catalyst and the hexafluoropropylene oxide dimer to a first preset temperature and maintaining the first preset temperature for a first preset time comprises: In an organic solvent and an inorganic metal salt catalyst, hexafluoropropylene oxide dimer is added dropwise, and after the addition is completed, the mixture is stabilized for a second preset time to obtain a mixture; The mixture is heated to a first preset temperature and maintained at the first preset temperature for a first preset time to obtain perfluoro-n-propyl vinyl ether.

3. The method according to claim 2, characterized in that Before the step of dropwise adding hexafluoropropylene oxide dimer into the organic solvent and the inorganic metal salt catalyst, the method further comprises: The organic solvent and the inorganic metal salt catalyst are cooled to a second preset temperature.

4. The method according to claim 1, characterized in that: The mass ratio of the hexafluoropropylene oxide dimer, the organic solvent and the inorganic metal salt catalyst is 1:(1-2):(0.01-1).

5. The method according to claim 1, characterized in that The inorganic metal salt catalyst includes at least one of CrCl3, SbCl3, FeCl3, and CaCl2.

6. The method according to claim 1, characterized in that The organic solvent includes at least one of methanol, ethanol, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, acetonitrile, propionitrile and dimethyl sulfoxide.

7. The method according to claim 2, characterized in that The first preset temperature is greater than 60°C and less than 150°C.

8. The method according to claim 2, characterized in that: The first preset time is 1-6 hours.

9. The method according to claim 2, characterized in that: The second preset time is 0.5h.

10. The method according to claim 2, characterized in that The second preset temperature is greater than 5°C and less than 30°C.

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