Method for preparing perfluoromethyl vinyl ether

Abstract

The invention provides a method for preparing perfluoromethyl vinyl ether, which comprises the following steps: carrying out ozone cracking reaction by using perfluoroolefin as a raw material, and separating and purifying to obtain trifluoromethyl fluoroformate, the preparation method comprises the following steps: reacting trifluoromethyl fluoroformate with hexafluoropropylene oxide to obtain perfluoro-2-methoxypropionyl fluoride, and further carrying out pyrolysis decarboxylation on the perfluoro-2-methoxypropionyl fluoride to obtain the perfluoromethyl vinyl ether. The method for preparing trifluoromethyl fluoroformate through ozone oxidative cracking of perfluoroolefin is mild in reaction condition, good in selectivity, simple in process, safe and reliable, the product is easy to separate, and the yield is high. Other products related in the process, such as trifluoroacetyl fluoride and heptafluoroisobutyryl fluoride, are also very important industrial intermediates which are difficult to obtain; the trifluoromethyl fluoroformate is used for replacing carbonyl fluoride to prepare perfluoro-2-methoxypropionyl fluoride, so that the defects that carbonyl fluoride is high in toxicity and has potential safety hazards in production and use are overcome, and the whole process of PMVE is safe and reliable.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, and particularly relates to a method for preparing perfluoromethyl vinyl ether. BACKGROUND

[0002] Perfluoromethyl vinyl ether (PMVE) is an important monomer for the synthesis of fluororubber and fluoroplastic, and has a wide range of uses in the development of new fluorine-containing polymers with excellent comprehensive performance due to its special structure. In addition, PMVE can also be used to produce new non-toxic and efficient insecticide, bifenthrin, also known as dimilin.

[0003] The research on the synthesis method of PMVE began in the 1950s. So far, the reported synthesis methods can be divided into two types according to their key raw materials: 1) perfluoro-2-methoxypropanoyl fluoride is prepared from carbonyl fluoride and hexafluoropropylene oxide (HFPO), and the latter is prepared into PMVE by a thermal cracking method with a catalyst and an alkali metal salt; or carbonyl fluoride and tetrafluoroethylene (TFE) or chlorotrifluoroethylene (CTFE) are used as raw materials to prepare PMVE by one-pot method. 2) trifluoromethyl-1,2-dichlorotrifluoroethyl ether is prepared from trifluoromethyl oxyfluoride (CF3OF) and 1,2-difluoro-1,2-dichloroethylene, and the latter is prepared into PMVE by zinc metal dechlorination or catalytic hydrogenation dechlorination method. Method 1) involves the use of carbonyl fluoride, which is highly toxic, and there are safety hazards in its production and use. Therefore, it is of great significance to develop a safe and low-toxic raw material intermediate that can replace carbonyl fluoride to prepare PMVE. Method 2) involves the use of CF3OF, which is expensive and dangerous due to the use of F2 in its preparation method. Meanwhile, CF3OF is highly reactive and toxic, and there are also safety hazards in its use. Therefore, the technical route based on CF3OF is not an ideal method for preparing perfluoromethyl vinyl ether. In summary, it is still of practical significance to explore new technical solutions for preparing perfluoromethyl vinyl ether.

[0004] Trifluoromethyl fluorocarbonate is a key raw material for preparing low-temperature fluororubber monomer MOVE, but it is not easy to obtain. Trifluoromethyl fluorocarbonate is much less toxic than carbonyl fluoride, and its boiling point is higher than that of the latter, so it is safer and more convenient to use. It has been found that trifluoromethyl fluorocarbonate can be used as a substitute for carbonyl fluoride in some fields. The existing synthesis methods of trifluoromethyl fluorocarbonate have the following shortcomings: 1) the reaction raw materials involve flammable and explosive dangerous substances such as CO, fluorine gas and CF3OF, or some expensive reagents that are difficult to produce on a large scale; 2) the reaction selectivity is poor, the product is not easy to control, and the yield is low; 3) the reaction conditions are harsh and the product contains corrosive components, so the equipment requirements are very high. In summary, there are still great obstacles in the industrial production of trifluoromethyl fluorocarbonate, and it is still of practical significance to explore new technical solutions for preparing trifluoromethyl fluorocarbonate. SUMMARY

[0005] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing perfluoromethyl vinyl ether, wherein the raw materials are readily available and inexpensive, the reaction conditions are mild, safe and reliable, and the yield is high.

[0006] To achieve the above objectives, the present invention provides a method for preparing perfluoromethyl vinyl ethers, comprising the following steps:

[0007] A) Using the perfluoroolefin shown in Formula I as a raw material, an ozone cracking reaction was carried out, followed by separation and purification to obtain trifluoromethyl fluoroformate;

[0008]

[0009] Among them, Rf1 and Rf2 are independently selected from F, C1 to C3 perfluoroalkyl groups.

[0010] B) Trifluoromethyl fluoroformate and hexafluoropropylene oxide were reacted to give perfluoro-2-methoxypropionyl fluoride; perfluoro-2-methoxypropionyl fluoride was further decarboxylated by heat to give perfluoromethyl vinyl ether.

[0011] One of the key technical problems to be solved by this invention is to use perfluoroolefins of Formula I as raw materials for ozone cracking reaction, and then separate and purify the products to obtain trifluoromethyl fluoroformate.

[0012] Preferably, Rf1 and Rf2 are independently selected from F, CF3 or CF(CF3)2.

[0013] More preferably, the perfluoroolefin is hexafluoropropylene, perfluoro-4-methyl-2-pentene, or perfluoro-3-isopropyl-4-methyl-2-pentene.

[0014] This invention proposes for the first time the preparation of trifluoromethyl fluoroformate from perfluoroolefins represented by Formula I. The perfluoroolefins represented by Formula I generate primary ozonides during ozone oxidation and cracking, which readily crack to generate intermediate perfluorocarbonyl oxides, especially trifluorocarbonyl oxides. These trifluorocarbonyl oxides readily and rapidly isomerize to form trifluoromethyl fluoroformate. Taking the ozone cracking of perfluoro-4-methyl-2-pentene as an example, during the reaction, its double bonds break, with the left-hand group mainly generating heptafluoroisobutyryl fluoride (i-C3F7COF), and the right-hand CF (CF3) group generating trifluoromethyl fluoroformate (CF3OCOF) or trifluoroacetyl fluoride (CF3COF). The main reaction products include trifluoroacetyl fluoride, heptafluoroisobutyryl fluoride, and trifluoromethyl fluoroformate. Purification of the products by distillation yields trifluoromethyl fluoroformate. The inventors discovered that the ratio of trifluoromethyl fluoroformate to trifluoroacyl fluoride in the products can be controlled by adjusting the cracking conditions. Specifically, the content of trifluoromethyl fluoroformate and trifluoroacetyl fluoride in the pyrolysis products can be controlled by changing the reaction conditions, including the pyrolysis temperature and the amount of reaction regulator. Pyrolysis of 1 mole of perfluoro-4-methyl-2-pentene can generate 0.75 moles of trifluoromethyl fluoroformate, while only 0.25 moles of trifluoroacetyl fluoride are produced.

[0015] The ozone decomposition reaction described above uses an ozone-oxygen mixture, wherein the ozone concentration is 1% to 50%, which is a volume concentration. In some specific embodiments of the present invention, the ozone concentration in the aforementioned oxygen-ozone mixture is approximately 100 mg / L.

[0016] Preferably, the molar ratio of the perfluoroolefin represented by Formula I to the consumed ozone is 1:(0.2-8), more preferably 1:(0.2-3).

[0017] The temperature for the above-mentioned ozone decomposition reaction is -100℃ to 100℃, more preferably -80℃ to 80℃, even more preferably -60℃ to 60℃, and even more preferably -50℃ to 50℃. In some specific embodiments of the present invention, the temperature for the above-mentioned ozone decomposition reaction is -50℃ or 40℃.

[0018] The pressure of the above-mentioned ozone decomposition reaction is 1 to 10 kg; more preferably 1 to 8 kg, and even more preferably 1 to 6 kg.

[0019] In the above ozone cracking reaction, solvent raw materials can be added for dilution as needed, or perfluoroolefins can be directly cracked. The solvent used is preferably a fluorocarbon solvent, which is preferably one or more of fluorinated hydrocarbons, fluorocarbon esters, hydrofluoroethers, and perfluoropolyethers. The fluorinated hydrocarbon is preferably CFC-113, the fluorocarbon ester is preferably ethyl trifluoroacetate, the hydrofluoroether is preferably Novec 7100, 7200, or 7500, and the perfluoropolyether is preferably Krytox GPL101, etc. The mass ratio of the solvent to the perfluoroolefin is preferably (0:100) to (80:20).

[0020] In the above-mentioned ozone decomposition reaction, a regulator can be added as needed to dilute the raw materials and control the composition of the product. The regulator is a proton-containing compound, including alcohols and acids. Preferably, the regulator is fluorocarbonate or fluorocarbon alcohol. More preferably, the fluorocarbonate includes trifluoroacetic acid, pentafluoropropionic acid, and heptafluoroisobutyric acid, etc., and the fluorocarbon alcohol includes trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol, etc. The mass ratio of the regulator to the perfluoroolefin is (0:100) to (80:20).

[0021] The above-mentioned ozone cracking reaction can be carried out in batch or continuous operation. The batch operation is as follows: perfluoroolefins, fluorocarbon solvents, and reaction regulators are added to the cracking reactor all at once, and then an ozone-oxygen mixture is continuously introduced at a set temperature for cracking until the perfluoroolefins are completely cracked. The continuous operation is as follows: perfluoroolefins, fluorocarbon solvents, and reaction regulators are first mixed in a certain proportion, then a portion of the mixture is added to the cracking reactor all at once, and then an ozone-oxygen mixture is continuously introduced at a set temperature for cracking, with the mixture continuously added to the cracking reactor at a certain rate during the process. The ozone cracking reaction has no special limitation on the reaction time. Preferably, for batch operation, the reaction can generally be stopped after the substrate is completely cracked; preferably, for continuous operation, the reaction can be stopped at any reaction time according to the actual needs of the reaction.

[0022] The present invention does not impose any particular limitation on the separation and purification method, which can be selected according to the boiling point of the product, such as condensation treatment based on the boiling point of the product.

[0023] Furthermore, when the raw material is hexafluoropropylene, the above method for preparing trifluoromethyl fluoroformate includes the following steps:

[0024] 1) In a dry reaction vessel, hexafluoropropylene is added, and then a mixture of oxygen and ozone is introduced to carry out ozone cracking, yielding crude products including carbonyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate; or, in a dry reaction vessel, fluorocarbon solvent and reaction regulator are added, and then a mixture of hexafluoropropylene, oxygen, and ozone is introduced to carry out ozone cracking, yielding crude products including carbonyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate.

[0025] 2) The crude product was separated and purified to obtain pure trifluoromethyl fluoroformate.

[0026] The equation for the above reaction is as follows:

[0027] CF2=CFCF3+(3+x) / 3O3→COF2+x CF3OCOF+(1-x)CF3COF+0.5O2

[0028] Where x = 0 to 1.

[0029] Further, in step 1) above, the molar ratio of hexafluoropropylene to ozone is 1:(0.2-8); preferably, the molar ratio of hexafluoropropylene to ozone is 1:(0.2-3).

[0030] Further, in step 1) above, the temperature of the ozone decomposition reaction is -100℃ to 100℃, more preferably -80℃ to 80℃, even more preferably -60℃ to 60℃, and even more preferably -50℃ to 50℃. In some specific embodiments of the present invention, the temperature of the above ozone decomposition reaction is -50℃ or 40℃.

[0031] Further, in step 1) above, the pressure inside the reactor is 1 to 10 kg; preferably, the pressure inside the reactor is 1 to 8 kg; more preferably, the pressure inside the reactor is 1 to 6 kg.

[0032] Further, in step 1) above, the ozone concentration in the oxygen-ozone mixture is 1% to 50%. The ozone concentration in the ozone mixture produced by commercial ozone generators generally does not exceed 20%, and the ozone concentration in the mixture can be increased through simple concentration methods to improve the ozone decomposition reaction rate. In some specific embodiments of the present invention, the ozone concentration in the above-mentioned oxygen-ozone mixture is approximately 100 mg / L.

[0033] Furthermore, in the ozone decomposition reaction, the raw material hexafluoropropylene can be diluted with solvent or other components as needed, or it can be directly decomposed. The solvent used is preferably a fluorocarbon solvent, which is preferably one or more of fluorinated hydrocarbons, fluorocarbon esters, hydrofluoroethers, and perfluoropolyethers. The fluorinated hydrocarbon is preferably CFC-113, the fluorocarbon ester is preferably ethyl trifluoroacetate, the hydrofluoroether is preferably Novec 7100, 7200, or 7500, and the perfluoropolyether is preferably Krytox GPL101, etc. The mass ratio of the solvent to hexafluoropropylene is preferably (0:100) to (80:20).

[0034] Furthermore, in the ozone decomposition reaction, a regulator can be added as needed to dilute the raw materials and control the composition of the product. The regulator is a proton-containing compound, including alcohols and acids. Preferably, the regulator is fluorocarbonate or fluorocarbon alcohol. More preferably, the fluorocarbonate includes trifluoroacetic acid, pentafluoropropionic acid, and heptafluoroisobutyric acid, etc., and the fluorocarbon alcohol includes trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol, etc. The mass ratio of the regulator to the perfluoroolefin is (0:100) to (80:20), more preferably 0% to 200% of the total mass of the perfluoroolefin, and even more preferably 5% to 100% of the total mass of the perfluoroolefin. Experimental results show that the addition of the reaction regulator increases the yield of trifluoromethyl fluoroformate from approximately 0-30% to approximately 30-70%.

[0035] Furthermore, in step 2), due to the significant difference in boiling points between carbamate, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate (at -84°C, -59°C, and -35°C, respectively), the reaction products are easily separated. Typically, during ultra-low temperature pyrolysis at -50°C, the carbamate and trifluoroacetyl fluoride products are discharged with the reaction gas stream, while the trifluoromethyl fluoroformate product is retained in the reaction vessel, thus achieving separation. During pyrolysis at temperatures above the boiling point of hexafluoropropylene (-29°C), such as 30°C, the product is discharged with the reaction tail gas, first entering a trifluoromethyl fluoroformate condenser (controlled at -60 to -40°C) to condense the trifluoromethyl fluoroformate, and then stored in a trifluoromethyl fluoroformate storage tank (controlled at -55 to -35°C). The carbamate and trifluoroacetyl fluoride products are discharged with the reaction tail gas and absorbed through an ethanol absorption tank (controlled at -30 to 20°C). Preferably, the trifluoromethyl fluoroformate condenser operates in a mode where the refrigerant and reaction products do not come into contact; more preferably, the trifluoromethyl fluoroformate condenser operates in a mode where the refrigerant and reaction products come into direct contact. The refrigerant is preferably an inert fluorocarbon solvent such as perfluoroolefins, hydrofluorocarbons, hydrofluoroethers, and perfluoropolyethers. The obtained trifluoromethyl fluoroformate is further purified by cryogenic distillation.

[0036] Furthermore, when the raw material is perfluoro-4-methyl-2-pentene, the above method for preparing trifluoromethyl fluoroformate includes the following steps:

[0037] 1) In a dry reaction vessel, perfluoro-4-methyl-2-pentene is added, and then an oxygen-ozone mixture is introduced to carry out ozone cracking, yielding crude products including trifluoroacetyl fluoride, heptafluoroisobutyryl fluoride, and trifluoromethyl fluoroformate; or, perfluoroolefins, fluorocarbon solvents, and reaction regulators are first mixed in a certain proportion, and then a portion of the perfluoroolefin, fluorocarbon solvent, and reaction regulator mixture is added to the cracking reaction vessel at one time. Then, an ozone-oxygen mixture is continuously introduced at a set temperature for cracking, and during the process, the perfluoroolefin, fluorocarbon solvent, and reaction regulator mixture is continuously added at a certain rate to obtain crude products including trifluoroacetyl fluoride, heptafluoroisobutyryl fluoride, and trifluoromethyl fluoroformate.

[0038] 2) The crude product was separated and purified to obtain pure trifluoromethyl fluoroformate.

[0039] The equation for the above reaction is as follows:

[0040] i-C3F7CF=CFCF3+(3+x) / 3O3→i-C3F7COF+x CF3OCOF+(1-x)CF3COF+0.5

[0041] O2

[0042] Where x = 0 to 1.

[0043] Further, in step 1) above, the molar ratio of perfluoro-4-methyl-2-pentene to ozone is 1:(0.2-8); preferably, the molar ratio of perfluoro-4-methyl-2-pentene to ozone is 1:(0.2-3).

[0044] Further, in step 1) above, the temperature of the ozone decomposition reaction is -100℃ to 100℃, more preferably -80℃ to 80℃, even more preferably -60℃ to 60℃, and even more preferably -50℃ to 50℃. In some specific embodiments of the present invention, the temperature of the above ozone decomposition reaction is -50℃, 25℃, or 40℃.

[0045] Further, in step 1) above, the pressure inside the reactor is 1 to 10 kg; preferably, the pressure inside the reactor is 1 to 8 kg; more preferably, the pressure inside the reactor is 1 to 6 kg.

[0046] Further, in step 1) above, the ozone concentration in the oxygen-ozone mixture is 1-50%. The ozone concentration in the ozone mixture produced by commercial ozone generators generally does not exceed 20%, and the ozone concentration in the mixture can be increased through simple concentration methods to improve the ozone decomposition reaction rate. In some specific embodiments of the present invention, the ozone concentration in the above-mentioned oxygen-ozone mixture is approximately 100 mg / L.

[0047] Furthermore, in the ozone decomposition reaction, the raw material perfluoro-4-methyl-2-pentene can be diluted by adding solvents or other components as needed, or it can be directly decomposed. The solvent used is preferably a fluorocarbon solvent, which is preferably one or more of fluorinated hydrocarbons, fluorocarbon esters, hydrofluoroethers, and perfluoropolyethers. The fluorinated hydrocarbon is preferably CFC-113, the fluorocarbon ester is preferably ethyl trifluoroacetate, the hydrofluoroether is preferably Novec 7100, 7200, or 7500, and the perfluoropolyether is preferably Krytox GPL101, etc. The mass ratio of the solvent to perfluoro-4-methyl-2-pentene is preferably (0:100) to (80:20).

[0048] Furthermore, in the ozone decomposition reaction, a regulator can be added as needed to dilute the raw materials and control the composition of the product. The regulator is a proton-containing compound, including alcohols and acids. Preferably, the regulator is fluorocarbonate or fluorocarbon alcohol. More preferably, the fluorocarbonate includes trifluoroacetic acid, pentafluoropropionic acid, and heptafluoroisobutyric acid, etc., and the fluorocarbon alcohol includes trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol, etc. The mass ratio of the regulator to the perfluoroolefin is (0:100) to (80:20), more preferably 0% to 200% of the total mass of the perfluoroolefin, and even more preferably 5% to 100% of the total mass of the perfluoroolefin. Experimental results show that the addition of the reaction regulator increases the yield of trifluoromethyl fluoroformate from approximately 0-30% to approximately 30-70%.

[0049] Furthermore, in step 2) above, due to the significant difference in boiling points between trifluoromethyl fluoroformate, heptafluoroisobutyryl fluoride, and trifluoroacetyl fluoride (at -35℃, 7-9℃, and -59℃ respectively), the reaction products are easily separated. During pyrolysis at an ultra-low temperature of -50℃, a small amount of product (trifluoroacetyl fluoride) is discharged with the reaction gas stream, while most of the product (heptafluoroisobutyryl fluoride and trifluoromethyl fluoroformate) is retained in the reaction vessel. After the reaction is completed, the reaction vessel is slowly heated and distilled. First, trifluoromethyl fluoroformate is distilled off, cooled by a trifluoromethyl fluoroformate condenser (controlled at -60 to -40℃), and then stored in a trifluoromethyl fluoroformate storage tank (controlled at -55 to -35℃). Further heating and distillation can distill off heptafluoroisobutyryl fluoride, which is then condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -30 to 0℃). During the cracking process, trifluoroacetyl fluoride is discharged with the reaction tail gas and then absorbed by an ethanol absorption tank (controlled at a temperature of -30 to 20°C). When cracking is performed at a higher temperature above 30°C, the products trifluoroacetyl fluoride, trifluoromethyl fluoroformate, and heptafluoroisobutyryl fluoride are discharged with the reaction gas stream. The three products can be separated by sequentially cooling the gas stream to near the boiling points of trifluoromethyl fluoroformate and heptafluoroisobutyryl fluoride. Specifically, the reaction product gas stream first passes through a first low-temperature condenser (a heptafluoroisobutyryl fluoride condenser, with its temperature controlled at -30 to -10°C) to condense the heptafluoroisobutyryl fluoride and store it in a heptafluoroisobutyryl fluoride storage tank (with its temperature controlled at -30 to 0°C); then it passes through a second low-temperature condenser (a trifluoromethyl fluoroformate condenser, with its temperature controlled at -60 to -40°C) to condense the trifluoromethyl fluoroformate and store it in a trifluoromethyl fluoroformate storage tank (with its temperature controlled at -55 to -35°C); finally, it passes through an ethanol absorption tank (with its temperature controlled at -30 to 20°C) to absorb trifluoroacetyl fluoride, generating ethyl trifluoroformate. Preferably, the trifluoromethyl fluoroformate condenser can be used in a mode where the refrigerant and reaction product do not come into contact; more preferably, the trifluoromethyl fluoroformate condenser can be used in a mode where the refrigerant and reaction product are in direct contact, in which case the refrigerant is preferably an inert fluorocarbon solvent such as perfluoroolefins, hydrofluorocarbons, hydrofluoroethers, and perfluoropolyethers. The obtained trifluoromethyl fluoroformate was further purified by cryogenic distillation.

[0050] Furthermore, when the raw material is perfluoro-3-isopropyl-4-methyl-2-pentene, the above method for preparing trifluoromethyl fluoroformate includes the following steps:

[0051] 1) In a dry reaction vessel, perfluoro-3-isopropyl-4-methyl-2-pentene is added, and then an oxygen-ozone mixture is introduced for ozone cracking to obtain crude products including trifluoroacetyl fluoride, trifluoromethyl fluoroformate, and perfluoro-2,4-dimethyl-3-pentanone; or, perfluoroolefins, fluorocarbon solvents, and reaction regulators are first mixed in a certain proportion, and then a portion of the perfluoroolefin, fluorocarbon solvent, and reaction regulator mixture is added to the cracking reaction vessel at one time. Then, an ozone-oxygen mixture is continuously introduced at a set temperature for cracking, and during the process, the perfluoroolefin, fluorocarbon solvent, and reaction regulator mixture is continuously added at a certain rate to obtain crude products including trifluoroacetyl fluoride, trifluoromethyl fluoroformate, and perfluoro-2,4-dimethyl-3-pentanone.

[0052] 2) The crude product was separated and purified to obtain pure trifluoromethyl fluoroformate.

[0053] The equation for the above reaction is as follows:

[0054] CF3CF(CF3)C(i-C3F7)=CFCF3+(3+x) / 3O3→i-C3F7COCF(CF3)CF3+x

[0055] CF3OCOF + (1-x)CF3COF + 0.5O2

[0056] Where x = 0 to 1.

[0057] Further, in step 1) above, the molar ratio of perfluoro-3-isopropyl-4-methyl-2-pentene to ozone is 1:(0.2-8); preferably, the molar ratio of perfluoro-3-isopropyl-4-methyl-2-pentene to ozone is 1:(0.2-3).

[0058] Further, in step 1) above, the temperature of the ozone decomposition reaction is -100℃ to 100℃, more preferably -80℃ to 80℃, even more preferably -60℃ to 60℃, and even more preferably -50℃ to 50℃. In some specific embodiments of the present invention, the temperature of the above ozone decomposition reaction is -50℃, 40℃, or 70℃.

[0059] Further, in step 1) above, the pressure inside the reactor is 1 to 10 kg; preferably, the pressure inside the reactor is 1 to 8 kg; more preferably, the pressure inside the reactor is 1 to 6 kg.

[0060] Further, in step 1), the ozone concentration in the oxygen-ozone mixture is 1% to 50%. The ozone concentration in the ozone mixture produced by commercial ozone generators generally does not exceed 20%, and the ozone concentration in the mixture can be increased through simple concentration methods to improve the ozone decomposition reaction rate. In some specific embodiments of the present invention, the ozone concentration in the above-mentioned oxygen-ozone mixture is approximately 100 mg / L.

[0061] Furthermore, in the ozone decomposition reaction, the raw material perfluoro-3-isopropyl-4-methyl-2-pentene can be diluted by adding solvents or other components as needed, or it can be directly decomposed. The solvent used is preferably a fluorocarbon solvent, which is preferably one or more of fluorinated hydrocarbons, fluorocarbon esters, hydrofluoroethers, and perfluoropolyethers. The fluorinated hydrocarbon is preferably CFC-113, the fluorocarbon ester is preferably ethyl trifluoroacetate, the hydrofluoroether is preferably Novec 7100, 7200, or 7500, and the perfluoropolyether is preferably Krytox GPL101, etc. The mass ratio of the solvent to perfluoro-3-isopropyl-4-methyl-2-pentene is preferably (0:100) to (80:20).

[0062] Furthermore, in the ozone decomposition reaction, a regulator can be added as needed to dilute the raw materials and control the composition of the product. The regulator is a proton-containing compound, including alcohols and acids. Preferably, the regulator is fluorocarbonate or fluorocarbon alcohol. More preferably, the fluorocarbonate includes trifluoroacetic acid, pentafluoropropionic acid, and heptafluoroisobutyric acid, etc., and the fluorocarbon alcohol includes trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol, etc. The mass ratio of the regulator to the perfluoroolefin is (0:100) to (80:20), more preferably 0% to 200% of the total mass of the perfluoroolefin, and even more preferably 5% to 100% of the total mass of the perfluoroolefin. Experimental results show that the addition of the reaction regulator increases the yield of trifluoromethyl fluoroformate from approximately 0-30% to approximately 30-70%.

[0063] Furthermore, in step 2) above, the reaction products are easily separated due to the significant difference in boiling points between trifluoroacetyl fluoride, trifluoromethyl fluoroformate, and perfluoro-2,4-dimethyl-3-pentanone. During pyrolysis at an ultra-low temperature of -50°C, a small amount of product (trifluoroacetyl fluoride) is discharged with the reaction gas stream, while most of the product (perfluoro-2,4-dimethyl-3-pentanone and trifluoromethyl fluoroformate) is retained in the reaction vessel. After the reaction is completed, the reaction vessel is slowly heated and distilled to distill off trifluoromethyl fluoroformate, which is then cooled in a trifluoromethyl fluoroformate condenser (controlled at -60 to -40°C) and stored in a trifluoromethyl fluoroformate storage tank (controlled at -55 to -35°C); while perfluoro-2,4-dimethyl-3-pentanone is retained in the reaction vessel. During the pyrolysis process, trifluoroacetyl fluoride is discharged with the reaction tail gas and then absorbed by an ethanol absorption tank (controlled at -30 to -20°C). Trifluoroacetyl fluoride, trifluoromethyl fluoroformate, and perfluoro-2,4-dimethyl-3-pentanone are separated. During pyrolysis at a relatively high temperature above 30°C, trifluoroacetyl fluoride and trifluoromethyl fluoroformate are discharged with the reaction gas stream and first enter a trifluoromethyl fluoroformate condenser (controlled at -60 to -40°C) to condense the trifluoromethyl fluoroformate, which is then stored in a trifluoromethyl fluoroformate storage tank (controlled at -55 to -35°C). Trifluoroacetyl fluoride is discharged with the reaction tail gas and then absorbed by an ethanol absorption tank (controlled at -30 to 20°C). Preferably, the trifluoromethyl fluoroformate condenser can be used in a mode where the refrigerant and reaction products do not contact; more preferably, the trifluoromethyl fluoroformate condenser can be used in a mode where the refrigerant and reaction products directly contact, in which case the refrigerant is preferably an inert fluorocarbon solvent such as perfluoroolefins, hydrofluorocarbons, hydrofluoroethers, and perfluoropolyethers. The obtained trifluoromethyl fluoroformate is further purified by cryogenic distillation.

[0064] The second key technical problem to be solved by this invention is to react trifluoromethyl fluoroformate and hexafluoropropylene oxide to obtain perfluoro-2-methoxypropionyl fluoride, and further decarboxylate perfluoro-2-methoxypropionyl fluoride by thermal decarboxylation to obtain perfluoromethyl vinyl ether. Specifically, in the first step, trifluoromethyl fluoroformate reacts with hexafluoropropylene oxide in the presence of a catalyst and solvent, and then the reaction product is distilled to obtain perfluoro-2-methoxypropionyl fluoride. In the second step, an alkali metal carbonate is dissolved in a solvent, and then perfluoro-2-methoxypropionyl fluoride is added dropwise, followed by thermal decarboxylation reaction to obtain crude PMVE, which is then purified by distillation to obtain perfluoromethyl vinyl ether.

[0065] Furthermore, the reaction of trifluoromethyl fluoroformate and hexafluoropropylene oxide described in this invention specifically refers to the reaction of trifluoromethyl fluoroformate with hexafluoropropylene oxide in the presence of a catalyst and a solvent, followed by distillation of the reaction product to obtain perfluoro-2-methoxypropionyl fluoride.

[0066] Furthermore, the present invention uses ether solvents, nitrile solvents, or sulfone solvents. Preferably, the solvent is one or more of tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, diethylene glycol diethyl ether, adiponitrile, acetonitrile, and sulfolane.

[0067] Furthermore, the catalyst used in this invention comprises alkali metal fluorides or Group IB transition metal halides. Preferably, the alkali metal fluoride is selected from one or more of lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride, and cesium fluoride, and the Group IB transition metal halide is selected from one or more of silver chloride, silver iodide, cupric chloride, and cuprous chloride.

[0068] Further, the molar ratio of solvent to catalyst in this invention is 5:1 to 1:5. Preferably, the molar ratio of solvent to catalyst is 3:1 to 1:3; more preferably, the molar ratio of solvent to catalyst is 2:1 to 1:2; and most preferably, the molar ratio of solvent to catalyst is 1:1.

[0069] Further, the reaction temperature of the present invention is -30℃ to 180℃. Preferably, the reaction temperature of the present invention is -30℃ to 120℃; more preferably, it is -30℃ to 80℃; most preferably, it is -30℃ to 60℃. The above reaction temperature is -30℃, -25℃, -20℃, -10℃, 0℃, 25℃, 40℃, 50℃, 60℃, or any of the above values ​​as the upper or lower limit.

[0070] Further, the operating pressure of the present invention is 1 to 20 kg. Preferably, the operating pressure of the present invention is 1 to 10 kg; more preferably, the operating pressure of the present invention is 1 to 10 kg; most preferably, the operating pressure of the present invention is 1 to 8 kg; particularly preferably, the operating pressure of the present invention is 1 to 6 kg.

[0071] Further, in the reaction process described in this invention, the feeding ratio of trifluoromethyl fluoroformate to HFPO is 1:1 to 1:5. In some embodiments, the feeding ratio of trifluoromethyl fluoroformate to HFPO in the reaction process described in this invention is 1:1 to 1:3; in some embodiments, the feeding ratio of trifluoromethyl fluoroformate to HFPO in the reaction process described in this invention is 1:1 to 1:2; in some embodiments, the feeding ratio of trifluoromethyl fluoroformate to HFPO in the reaction process described in this invention is 1:1 to 1:1.5.

[0072] After the reaction is complete, the product is distilled to obtain perfluoro-2-methoxypropionyl fluoride. The product distillation can be performed under normal pressure or under pressure; the distillation temperature is 10–80°C, the distillation pressure is 0–5 kg, and the distillation separation reflux ratio is 10:1–0.1:1.

[0073] Furthermore, the thermal decarboxylation reaction of perfluoro-2-methoxypropionyl fluoride described in this invention specifically refers to adding an alkali metal carbonate to a solvent, then adding perfluoro-2-methoxypropionyl fluoride dropwise, followed by thermal decarboxylation reaction to obtain crude PMVE, which is then purified by distillation to obtain perfluoromethyl vinyl ether.

[0074] Furthermore, the solvents described in this invention include ether solvents, nitrile solvents, or sulfone solvents. Preferably, the solvents include one or more of tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, diethylene glycol diethyl ether, adiponitrile, and sulfolane.

[0075] Furthermore, the alkali metal carbonates described in this invention include one or more of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate.

[0076] Furthermore, the feeding ratio of perfluoro-2-methoxy-propionyl fluoride to alkali metal carbonate in this invention is 1:2 to 1:5;

[0077] The feeding ratio of perfluoro-2-methoxy-propionyl fluoride and alkali metal carbonate in this invention can be 1:2, 1:3, 1:4 or 1:5; or any value between the two mentioned above.

[0078] Furthermore, the dropping temperature described in this invention is 20℃ to 50℃. Preferably, it is 20℃ to 40℃; more preferably, it is 20℃ to 30℃. 20℃, 40℃, 50℃, or any of the above values ​​may be the upper or lower limit. The dropping rate is not specifically limited, but in principle, it is ensured that the reaction temperature does not exceed the target value.

[0079] Furthermore, the thermal decarboxylation temperature of perfluoro-2-methoxypropionyl fluoride described in this invention is 100℃ to 200℃. The thermal decarboxylation temperature of perfluoro-2-methoxypropionyl fluoride described in this invention is 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃, 190℃, 200℃, or any of the above values ​​as the upper or lower limit.

[0080] Further, the operating pressure of the present invention is 1 to 20 kg. Preferably, the operating pressure of the present invention is 1 to 10 kg; preferably, the operating pressure of the present invention is 1 to 10 kg; preferably, the operating pressure of the present invention is 1 to 8 kg; preferably, the operating pressure of the present invention is 1 to 6 kg.

[0081] After the reaction was completed, the product was distilled to obtain perfluoromethyl vinyl ether.

[0082] The distillation can be atmospheric distillation or pressurized distillation; the distillation temperature is 10-60℃, the distillation pressure is 0-10 kg, and the distillation separation reflux ratio is 10:1-0.1:1.

[0083] The present invention has the following advantages:

[0084] First, the raw materials hexafluoropropylene and perfluoroolefins are commercially available, readily accessible, and inexpensive. Second, the ozone oxidation cracking of perfluoroolefins to prepare trifluoromethyl fluoroformate (PMVE) involves mild reaction conditions, good selectivity, a simple and safe process, and easy product separation with a high yield. Furthermore, other products involved in the process, trifluoroacetyl fluoride and heptafluoroisobutyryl fluoride, are also important and difficult-to-obtain industrial intermediates with significant industrial value. Third, replacing carbonyl fluoride with trifluoromethyl fluoroformate in the preparation of perfluoro-2-methoxypropionyl fluoride overcomes the drawbacks of carbonyl fluoride, such as high toxicity and safety hazards in its production and use, making the entire PMVE process safer, more reliable, and more suitable for industrial production. Detailed Implementation

[0085] To further illustrate the present invention, the method for preparing perfluoromethyl vinyl ether provided by the present invention will be described in detail below with reference to embodiments.

[0086] Example 1: Ozone Crack of Perfluoro-4-Methyl-2-pentene

[0087] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0088] Under nitrogen protection, 3 kg of perfluoro-4-methyl-2-pentene was added. The reactor temperature was raised to approximately 40°C, and the ozone generator was turned on. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / min to oxidize and decompose the perfluoro-4-methyl-2-pentene. The reaction pressure was 0–0.1 MPa. After 360 hours, the perfluoro-4-methyl-2-pentene was completely decomposed, and the reaction ended. During the reaction, the product gas stream first passes through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C). Then it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, the trifluoroisobutyryl fluoride is absorbed by an ethanol absorption tank (controlled at -30°C), forming ethyl trifluoroacetate and hydrogen fluoride. The remaining tail gas is directly vented. After the reaction is complete, 864 g of heptafluoroisobutyryl fluoride is collected, with a yield of 40%. 19 F NMR (400MHz) δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 330g, yield 25%.19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 426g, yield 30%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0089] Example 2: Ozone pyrolysis of perfluoro-4-methyl-2-pentene

[0090] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0091] Under nitrogen protection, 2 kg of ethyl trifluoroacetate was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. The reactor temperature was raised to approximately 40°C, and the ozone generator was turned on. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / min to oxidize and decompose the perfluoro-4-methyl-2-pentene. The reaction pressure was 0–0.1 MPa. After 240 hours, the perfluoro-4-methyl-2-pentene was completely decomposed, and the reaction ended. During the reaction, the product gas stream first passes through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C). Then, it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, the trifluoroisobutyryl fluoride is absorbed by an ethanol absorption tank (controlled at -30°C), forming ethyl trifluoroacetate and hydrogen fluoride. The remaining tail gas is directly vented. After the reaction is complete, 972g of heptafluoroisobutyryl fluoride is collected, with a yield of approximately 45%. 19 F NMR (400MHz) δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 436g, yield 33%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 568g, yield 40%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0092] Example 3: Ozone pyrolysis of perfluoro-4-methyl-2-pentene

[0093] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0094] Under nitrogen protection, 2 kg of trifluoroethanol was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. When the material was heated to 40°C, an ozone generator was turned on, and an oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to oxidize and crack the perfluoro-4-methyl-2-pentene. The reaction pressure was controlled at 0–0.1 MPa during the cracking process. After 192 hours, the perfluoro-4-methyl-2-pentene was completely cracked, and the reaction ended. The product gas carried in the tail gas during the reaction was absorbed by a trifluoroethanol absorption tank (controlled at -30°C). After the reaction, the materials from the reactor and the trifluoroethanol absorption tank were combined, washed with ice water, dried, and distilled to collect 1421 g of trifluoroethyl heptafluoroisobutyrate, with a yield of 48% and a purity of 95%. 19 F NMR (400MHz) δ-79.2 (d, 6F), -81.5 (t, 3F), -186 (m, 1F); 1 ¹H NMR (400MHz, CDCl₃) δ 4.6 (q, 2H). 1198 g of trifluoroethyl fluoroformate, yield 41%, purity 85%. 19 F NMR (400MHz) δ-21.7 (s, 1F), -81.5 (t, 3F); 1 ¹H NMR (400MHz, CDCl₃) δ 4.5 (q, 2H). 686g of trifluoroethyl trifluoroacetate, yield approximately 35%, purity 88%. 19 F NMR (400MHz) δ-79.5 (s, 3F), -81.5 (t, 3F); 1 H NMR (400MHz, CDCl3) δ4.5 (q, 2H).

[0095] Example 4: Ozone pyrolysis of perfluoro-4-methyl-2-pentene

[0096] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0097] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. When the material was heated to 40°C, the ozone generator was turned on, and an oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to oxidize and decompose the perfluoro-4-methyl-2-pentene. During the decomposition process, the reaction temperature was controlled at 40°C, and the reaction pressure was 0–0.1 MPa. After 60 hours, the perfluoro-4-methyl-2-pentene was completely decomposed, and the reaction ended. During the reaction, the product gas stream first passes through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C); then it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C); finally, it passes through an ethanol absorption tank (controlled at -30°C) to absorb the trifluoroyl fluoride, forming ethyl trifluoroacetate and hydrogen fluoride; the residual tail gas is directly vented. After the reaction is complete, 1534 g of heptafluoroisobutyryl fluoride is collected, with a yield of 71%. 19 F NMR (400MHz) δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 528g, yield 40%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 710g, yield 50%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4(t,3H), 4.4(q,2H).

[0098] Example 5: Ozone pyrolysis of perfluoro-4-methyl-2-pentene

[0099] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0100] Under nitrogen protection, 0.5 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. When the material was heated to 40°C, the ozone generator was turned on, and an oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to carry out ozone oxidation and cracking of perfluoro-4-methyl-2-pentene. During the cracking process, the reaction temperature was controlled at 40°C and the reaction pressure was 0–0.1 MPa. After 84 hours, the raw material perfluoro-4-methyl-2-pentene was completely cracked, and the reaction ended. During the reaction, the product gas stream first passes through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C). Then, it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, the trifluoroisobutyryl fluoride is absorbed by an ethanol absorption tank (controlled at -30°C), forming ethyl trifluoroacetate and hydrogen fluoride. The remaining tail gas is directly vented. After the reaction, 1620 g of heptafluoroisobutyryl fluoride was collected, with a yield of 75%. 19 F NMR (400MHz): δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 898g, yield 68%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 327g, yield 23%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4(t,3H), 4.4(q,2H).

[0101] Example 6: Ozone Crack of Perfluoro-4-Methyl-2-pentene

[0102] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0103] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. The reactor temperature was controlled at approximately 25°C, and the ozone generator was turned on. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / min to oxidize and decompose the perfluoro-4-methyl-2-pentene. The reaction pressure was 0–0.1 MPa. After 120 hours, the perfluoro-4-methyl-2-pentene was completely decomposed, and the reaction ended. During the reaction, the product gas stream first passes through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C). Then it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, it passes through an ethanol absorption tank (controlled at -30°C) to absorb the trifluoroyl fluoride, forming ethyl trifluoroacetate and hydrogen fluoride. The remaining tail gas is directly vented. After the reaction is complete, 1512 g of heptafluoroisobutyryl fluoride is collected, with a yield of 70%. 19 F NMR (400MHz) δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 449g, yield 34%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 781g, yield 55%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0104] Example 7: Ozone Crack of Perfluoro-4-Methyl-2-pentene

[0105] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to -50°C.

[0106] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. When the material cooled to -50°C, the ozone generator was turned on, and an oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to carry out ozone oxidation and cracking of perfluoro-4-methyl-2-pentene. During the cracking process, the reaction temperature was controlled at -50°C and the reaction pressure was 0–0.1 MPa. After 240 hours, the raw material perfluoro-4-methyl-2-pentene was completely cracked, and the reaction ended. Most of the heptafluoroyl fluoride and trifluoromethyl fluoroformate products generated during the cracking process are condensed in the reactor. Small amounts of heptafluoroisobutyryl fluoride, trifluoromethyl fluoroformate, and trifluoroyl fluoride carried in the reaction tail gas are first passed through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C). Then, it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, trifluoroyl fluoride is absorbed by an ethanol absorption tank (controlled at -30°C) to form ethyl trifluoroacetate and hydrogen fluoride. The remaining tail gas is directly discharged into the atmosphere. After the reaction was completed, the temperature of the reactor was first controlled at -30℃, and trifluoromethyl fluoroformate was slowly discharged. The trifluoromethyl fluoroformate was condensed in a trifluoromethyl fluoroformate condenser and stored in a trifluoromethyl fluoroformate storage tank. Then, the temperature of the reactor was controlled at 15℃, and heptafluoroisobutyryl fluoride was slowly discharged. The heptafluoroisobutyryl fluoride was condensed in a heptafluoroisobutyryl fluoride condenser and stored in a heptafluoroisobutyryl fluoride storage tank. A total of 1404 g of heptafluoroisobutyryl fluoride was collected, with a yield of 65%. 19 F NMR (400MHz) δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 396g, yield 30%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). 540 g of ethyl trifluoroacetate was collected in an ethanol absorption vessel, yield 38%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0107] Example 8: Perfluoro-4-methyl-2-pentene ozone pyrolysis (continuous ozone pyrolysis)

[0108] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0109] Under nitrogen protection, 0.5 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-4-methyl-2-pentene. The reactor temperature was raised to approximately 40°C, and the ozone generator was turned on. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / min to oxidize and decompose the perfluoro-4-methyl-2-pentene under an ozone pressure of 0–0.1 MPa. Every 24 hours, a mixture of 0.2 kg of trifluoroacetic acid and 0.5 kg of perfluoro-4-methyl-2-pentene was added. The reaction was stopped after 144 hours. During the reaction, the product gas stream first passes through a heptafluoroisobutyryl fluoride condenser (controlled at -30°C), where most of the heptafluoroisobutyryl fluoride is condensed and stored in a heptafluoroisobutyryl fluoride storage tank (controlled at -20°C). Then, it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate is condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, it passes through an ethanol absorption tank (controlled at -30°C) to absorb trifluoroacetyl fluoride, forming ethyl trifluoroacetate and hydrogen fluoride. The remaining tail gas is directly vented. After the reaction, 3009 g of heptafluoroisobutyryl fluoride was collected, with a yield of 76%. 19 F NMR (400MHz) δ28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 1669g, yield 69%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 625g, yield 24%. 19 FNMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0110] Example 9: Ozone Decomposition of Hexafluoropropylene

[0111] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the system was pressurized and cooled to -50°C.

[0112] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by the metering of hexafluoropropylene gas through a gas mass flow meter to cool it into a liquid state, for a total of 3 kg of hexafluoropropylene. Stirring was started, and an ozone generator was activated. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / min to perform ozone oxidation and cracking of hexafluoropropylene. During the cracking process, the reaction temperature was controlled at -50℃, and the reaction pressure at 0–0.1 MPa. The reaction product gas stream first passed through a trifluoroacetyl fluoride cryogenic condenser (controlled at -70℃) to condense trifluoroacetyl fluoride, which was then stored in a trifluoroacetyl fluoride storage tank (controlled at -70℃). It was then absorbed through an ethanol absorption tank (controlled at 10–20℃). The reaction was completed after 240 hours. 1267 g of trifluoromethyl fluoroformate was collected in the reactor, with a yield of 48%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Approximately 812 g of trifluoroacetyl fluoride was collected in a cryogenic condenser, yielding 35%. 19 F NMR (400MHz) δ -9.5 (s, 1F), -79.5 (s, 3F). 1252 g of diethyl carbonate was collected in an ethanol absorption tank. 1 ¹H NMR (400MHz, CDCl₃) δ 1.3 (t, 6H), 4.4 (q, 4H), corresponding to 700 g of carbonyl fluoride, yield 53%.

[0113] Example 10 Ozone Decomposition of Hexafluoropropylene

[0114] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0115] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, and the reactor temperature was controlled at 40°C. Stirring was started, and the ozone generator was activated. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / min, while hexafluoropropylene was simultaneously introduced into the reactor at 78 SCCM / min for ozone oxidation and cracking. During the cracking process, the reaction temperature was controlled at 40°C, and the reaction pressure at 0–0.1 MPa. The reaction product gas stream first passed through a trifluoromethyl fluoroformate condenser (controlled at -55°C) to condense the trifluoromethyl fluoroformate and store it in a trifluoromethyl fluoroformate storage tank (-45°C); then, it passed through an ultra-low temperature condenser (controlled at -70°C) to condense the trifluoroacetyl fluoride and store it in a trifluoroacetyl fluoride storage tank (-60°C); finally, it was absorbed through an ethanol absorption tank (controlled at 10–20°C). The reaction was terminated after 120 hours. 1452g of trifluoromethyl fluoroformate was collected in the tank, with a yield of 55%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Approximately 696 g of trifluoroacetyl fluoride was collected in a cryogenic condenser, yielding 30%. 19 F NMR (400MHz) δ -9.5 (s, 1F), -79.5 (s, 3F). 1417 g of diethyl carbonate was collected in an ethanol absorption vessel, corresponding to 792 g of carbamate, yielding 60%.

[0116] Example 11: Ozone Crack of Perfluoro-3-Isopropyl-4-Methyl-2-pentene

[0117] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0118] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-3-isopropyl-4-methyl-2-pentene. The reactor temperature was raised to approximately 40°C, and the ozone generator was turned on. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to oxidize and decompose perfluoro-3-isopropyl-4-methyl-2-pentene under ozone conditions at a pressure of 0–0.2 MPa. The reaction was completed after 72 hours. During the reaction, the product gas stream passed through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate was condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, the product gas was absorbed by an ethanol absorption tank (controlled at -30°C) to form ethyl trifluoroformate and hydrogen fluoride. The residual tail gas was directly vented. After the reaction, 528 g of trifluoromethyl fluoroformate was collected, with a yield of 60%. 19F NMR (400 MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). 1586 g of perfluoro-2,4-dimethyl-3-pentanone was collected in the reactor, yield 65%. 19 F NMR (400MHz) δ -76.8 (d, 12F), -191.3 (m, 2F). 190 g of ethyl trifluoroacetate was collected in an ethanol absorption vessel, yield 20%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0119] Example 12: Ozone pyrolysis of perfluoro-3-isopropyl-4-methyl-2-pentene

[0120] The reaction was carried out in a 5L stainless steel (316L) reaction system, with a condenser installed at the gas outlet of the reactor. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained until the temperature dropped to room temperature. The condenser temperature was controlled between -15°C and -25°C.

[0121] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-3-isopropyl-4-methyl-2-pentene. The reactor temperature was raised to approximately 70°C, and the ozone generator was turned on. An oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to oxidize and decompose perfluoro-3-isopropyl-4-methyl-2-pentene under ozone pressure of 0–0.2 MPa. The reaction was completed after 48 hours. During the reaction, the product gas stream passed through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate was condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, the product gas was absorbed by an ethanol absorption tank (controlled at -30°C) to form ethyl trifluoroformate and hydrogen fluoride. The residual tail gas was directly vented. After the reaction, 580 g of trifluoromethyl fluoroformate was collected, with a yield of 66%. 19 F NMR (400 MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). 1732 g of perfluoro-2,4-dimethyl-3-pentanone was collected in the reactor, yield 71%. 19 F NMR (400MHz) δ -76.8 (d, 12F), -191.3 (m, 2F). 208 g of ethyl trifluoroacetate was collected in an ethanol absorption vessel, yield 22%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0122] Example 13: Ozone pyrolysis of perfluoro-3-isopropyl-4-methyl-2-pentene

[0123] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to -50°C.

[0124] Under nitrogen protection, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-3-isopropyl-4-methyl-2-pentene. Once the material cooled to -50°C, the ozone generator was turned on, and an oxygen / ozone mixture (ozone concentration: approximately 100 mg / L) was introduced into the reactor at a rate of 200 SCCM / MIN to oxidize and decompose the perfluoro-3-isopropyl-4-methyl-2-pentene. During the decomposition process, the reaction temperature was controlled at -50°C, and the reaction pressure was 0–0.2 MPa. The reaction was completed after 168 hours. Most of the trifluoromethyl fluoroformate product generated during the cracking process was condensed in the reactor. During the reaction, the tail gas flow passed through a trifluoromethyl fluoroformate condenser (controlled at -55°C), and a small amount of trifluoromethyl fluoroformate entrained in the tail gas was condensed and stored in a trifluoromethyl fluoroformate storage tank (-40°C). Finally, trifluoroyl fluoride was absorbed through an ethanol absorption tank (controlled at -30°C) to form ethyl trifluoroformate and hydrogen fluoride; the remaining tail gas was directly vented. After the cracking reaction was completed, the reactor temperature was controlled at -15°C, and the trifluoromethyl fluoroformate was slowly discharged, where it was condensed in the trifluoromethyl fluoroformate condenser. A total of 335g of trifluoromethyl fluoroformate was collected, with a yield of 38%. 19 F NMR (400MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). 1391 g of perfluoro-2,4-dimethyl-3-pentanone was collected in the reactor, yield 57%. 19 F NMR (400MHz) δ -76.8 (d, 12F), -191.3 (m, 2F). 313 g of ethyl trifluoroacetate was collected in an ethanol absorption vessel, yield 33%. 19 F NMR (400MHz) δ-80.5 (s, 3F); 1 H NMR (400MHz, CDCl3) δ1.4 (t, 3H), 4.4 (q, 2H).

[0125] Example 14, Synthesis of perfluoro-2-methoxypropionyl fluoride

[0126] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to 30°C.

[0127] Under nitrogen protection, 1 kg of dry acetonitrile was added, followed by 278.4 g (4.8 mol) of potassium fluoride. The reactor was heated to 50°C, and 264 g (2 mol) of trifluoromethyl fluoroformate was introduced and the reaction was maintained at this temperature for 6 hours. Subsequently, HFPO was introduced into the reactor at a flow rate of 100 SCCM using a flow meter. After 24 hours, the venting was stopped, with a total of 797 g introduced. The vented gas from the reactor was collected in a -20°C stainless steel receiving tank to obtain crude perfluoro-2-methoxypropionyl fluoride. The crude product was then distilled to obtain 705 g of perfluoro-2-methoxypropionyl fluoride, with a yield of 76% and a purity of 99%. 19 F NMR (400 MHz) δ 23.2 (s, 1F), -56.7 (s, 3F), -84.5 (d, 3F), -132.1 (q, 1F). 155 g of hexafluoropropylene oxide dimer was obtained, yield 19%, purity 95%. 36 g of hexafluoropropylene oxide trimer was collected in the reactor, yield 4.5%.

[0128] Implementation 15, Synthesis of perfluoro-2-methoxypropionyl fluoride

[0129] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to 30°C.

[0130] Under nitrogen protection, 1 kg of dry diethylene glycol dimethyl ether was added, followed by 278.4 g (4.8 mol) of potassium fluoride. The reactor was heated to 50°C, and 264 g (2 mol) of trifluoromethyl fluoroformate was introduced and the reaction was maintained at this temperature for 6 hours. Subsequently, HFPO was introduced into the reactor at a flow rate of 100 SCCM using a flow meter. After 24 hours, the aeration was stopped, and a total of 797 g of HFPO was introduced. The vented gas from the reactor was collected in a -20°C stainless steel receiving tank to obtain crude perfluoro-2-methoxypropionyl fluoride. The crude product was then distilled to obtain 687 g of perfluoro-2-methoxypropionyl fluoride, with a yield of 74% and a purity of 99%. 19 F NMR (400 MHz) δ 23.2 (s, 1F), -56.7 (s, 3F), -84.5 (d, 3F), -132.1 (q, 1F). 135 g of hexafluoropropylene oxide dimer was obtained, yield 17%, purity 95%. 40 g of hexafluoropropylene oxide trimer was collected in the reactor, yield 5%.

[0131] Implementation 16, Synthesis of perfluoro-2-methoxypropionyl fluoride

[0132] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to 30°C.

[0133] Under nitrogen protection, 1 kg of dry acetonitrile was added, followed by 607.6 g (4 mol) of cesium fluoride. The reactor was heated to 50°C, and 264 g (2 mol) of trifluoromethyl fluoroformate was introduced and the reaction was maintained at this temperature for 6 h. Subsequently, HFPO was introduced into the reactor at a flow rate of 100 SCCM using a flow meter. After 24 hours, the venting was stopped, with a total of 797 g introduced. The vented gas from the reactor was collected as crude perfluoro-2-methoxypropionyl fluoride in a -20°C stainless steel receiving tank. The crude product was then distilled to obtain 742 g of perfluoro-2-methoxypropionyl fluoride, with a yield of 80% and a purity of 99%. 19 F NMR (400 MHz) δ 23.2 (s, 1F), -56.7 (s, 3F), -84.5 (d, 3F), -132.1 (q, 1F). 104 g of hexafluoropropylene oxide dimer was obtained, yield 13%, purity 95%. 24 g of hexafluoropropylene oxide trimer was collected in the reactor, yield 3%.

[0134] Example 17, PMVE Synthesis

[0135] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to 30°C.

[0136] 233.2 g of sodium carbonate (2.2 mol) and 800 g of diethylene glycol dimethyl ether were added to a reaction vessel. Then, 232 g (1 mol) of perfluoro-2-methoxypropionyl fluoride was slowly added dropwise to the reaction vessel. The reaction was carried out at 30°C for 12 h to generate perfluoro-2-methoxycarboxylate. The reaction vessel was then heated to 120°C for decarboxylation. Simultaneously, the solvent was refluxed into the reaction system through a condenser column. The crude product was collected in a cold trap at -50°C. CO2 was discharged as gas after passing through the cold trap. 154.4 g of product was collected in the cold trap, with a yield of 93% and a purity of 94% (GC). 19 F NMR (400MHz) δ -64.3 (s, 3F), -119.2 (m, 1F), -126.8 (m, 1F), -141.3 (m, 1F).

[0137] Example 18, PMVE Synthesis

[0138] The reaction was carried out in a 5L stainless steel (316L) reaction system. Before feeding, the reaction system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen gas was introduced and the pressure was maintained until the temperature dropped to 30°C.

[0139] 276.4 g of potassium carbonate (2 mol) and 800 g of diethylene glycol dimethyl ether were added to a reactor. Then, 232 g (1 mol) of perfluoro-2-methoxypropionyl fluoride was slowly added dropwise to the reactor. The reactor was heated to 30°C and reacted for 12 h to generate perfluoro-2-methoxycarboxylate. The reactor was then heated to 120°C for decarboxylation. Simultaneously, the solvent was refluxed into the reaction system through a condenser column. The crude product was collected in a -50°C cold trap. CO2 was discharged as gas after passing through the cold trap. 157.7 g of product was collected in the cold trap, with a yield of 95% and a purity of 93% (GC). 19 F NMR (400MHz) δ -64.3 (s, 3F), -119.2 (m, 1F), -126.8 (m, 1F), -141.3 (m, 1F).

[0140] The above description of the embodiments is only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

1. A method for preparing perfluoromethyl vinyl ethers, characterized in that, Includes the following steps: A) Using the perfluoroolefin shown in Formula I as a raw material, an ozone cracking reaction was carried out, followed by separation and purification to obtain trifluoromethyl fluoroformate; Among them, Rf1 and Rf2 are independently selected from F, C1 to C3 perfluoroalkyl groups; B) Trifluoromethyl fluoroformate and hexafluoropropylene oxide were reacted to give perfluoro-2-methoxypropionyl fluoride; perfluoro-2-methoxypropionyl fluoride was further decarboxylated by heat to give perfluoromethyl vinyl ether.

2. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, The Rf1 and Rf2 are independently selected from F, CF3 or CF(CF3)2; the perfluoroolefin is hexafluoropropylene, perfluoro-4-methyl-2-pentene or perfluoro-3-isopropyl-4-methyl-2-pentene.

3. The method for preparing trifluoromethyl fluoroformate according to claim 1, characterized in that, The ozone decomposition reaction uses an ozone-oxygen mixture, wherein the ozone concentration is 1% to 50%. The molar ratio of the perfluoroolefin shown in Formula I to ozone is 1:(0.2~8); The temperature of the ozone decomposition reaction is -100℃ to 150℃; The pressure of the ozone decomposition reaction is 1 to 10 kg.

4. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, The solvent used in the ozone decomposition reaction is a fluorocarbon solvent; The mass ratio of the solvent to the perfluoroolefin is (0:100) to (80:20); The fluorocarbon solvent is one or more of fluorocarbons, fluorocarbon esters, hydrofluoroethers, and perfluoropolyethers.

5. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, A reaction regulator is added during the ozone decomposition reaction to control the proportion of trifluoromethyl fluoroformate in the products. The mass ratio of the reaction regulator to the perfluoroolefin is (0:100) to (80:20); The reaction regulator is a proton-containing compound, and the reaction regulator includes alcohols and / or acidic compounds; The alcohol is preferably a fluorocarbon alcohol, and more preferably includes one or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol and octafluoropentanol; The acidic compound is preferably fluorocarbonic acid, and more preferably includes one or more of trifluoroacetic acid, pentafluoropropionic acid and heptafluoroisobutyric acid.

6. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, Using hexafluoropropylene as a raw material, the separation and purification process at low temperature involves the following steps: the reaction product gas stream first passes through a first low-temperature condenser to collect trifluoroacetyl fluoride; then it passes through an ethanol absorption tank to absorb carbonyl fluoride, generating ethyl fluoroformate and diethyl carbonate; trifluoromethyl fluoroformate is collected in the reaction vessel. At high temperature, the separation and purification process involves the following steps: the reaction product gas stream first passes through a first low-temperature condenser to collect trifluoromethyl fluoroformate; then it passes through a second low-temperature condenser to collect trifluoroacetyl fluoride; finally, it passes through an ethanol absorption tank to absorb residual trifluoroacetyl fluoride, generating ethyl trifluoroformate. When perfluoro-4-methyl-2-pentene is used as a raw material, the separation and purification process is as follows: the reaction product gas stream first passes through a first low-temperature condenser to collect heptafluoroisobutyryl fluoride; then passes through a second low-temperature condenser to collect trifluoromethyl fluoroformate; finally, it passes through an ethanol absorption tank to absorb trifluoroacetyl fluoride and generate ethyl trifluoroacetate. When perfluoro-3-isopropyl-4-methyl-2-pentene is used as a raw material, the separation and purification are specifically as follows: the reaction product gas stream first passes through a first low-temperature condenser to collect trifluoromethyl fluoroformate; then it passes through an ethanol absorption tank to absorb trifluoroacetyl fluoride to generate ethyl trifluoroacetate; and the reaction vessel collects perfluoro-2,4-dimethyl-3-pentanone.

7. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, Step B) specifically includes: Trifluoromethyl fluoroformate reacts with hexafluoropropylene oxide in the presence of a catalyst and solvent, and then the reaction product is distilled to obtain perfluoro-2-methoxypropionyl fluoride. The catalyst comprises an alkali metal fluoride or a Group IB transition metal halide; the alkali metal fluoride is selected from one or more of lithium fluoride, sodium fluoride, potassium fluoride, rubidium fluoride and cesium fluoride; the Group IB transition metal halide is selected from one or more of silver chloride, silver iodide, cupric chloride and cuprous chloride. The solvent includes ether solvents, nitrile solvents, or sulfone solvents; preferably, the solvent includes one or more of tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, diethylene glycol diethyl ether, adiponitrile, acetonitrile, and sulfolane. The mass ratio of the solvent to the catalyst is 100:1 to 1:

1.

8. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, The reaction temperature in step B) is -30℃ to 180℃; the operating pressure is 1 to 20 kg; and the feeding ratio of trifluoromethyl fluoroformate to HFPO during the reaction is 1:1 to 1:

5. The reaction is followed by pressurized distillation separation; the distillation separation temperature is 10-80℃, the distillation separation pressure is 0-5 kg, and the distillation separation reflux ratio is 10:1-0.1:

1.

9. The method for preparing perfluoromethyl vinyl ether according to claim 1, characterized in that, Step B) includes: An alkali metal carbonate is dissolved in a solvent, and perfluoro-2-methoxypropionyl fluoride is added dropwise. The mixture is then heated to decarboxylate the fluoride, yielding crude PMVE. The crude product is then purified by distillation to obtain perfluoromethyl vinyl ether.

10. The method for preparing perfluoromethyl vinyl ether according to claim 9, characterized in that, The solvent includes ether solvents, nitrile solvents, or sulfone solvents; preferably, the solvent includes one or more of tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, diethylene glycol diethyl ether, adiponitrile, acetonitrile, and sulfolane. The alkali metal carbonates include one or more of lithium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, or cesium carbonate. The molar ratio of the solvent to the alkali metal carbonate is 5:1 to 1:5; The feeding ratio of perfluoro-2-methoxy-propionyl fluoride to alkali metal carbonate is 1:2 to 1:5; The dropping temperature is 20–50℃; the temperature for thermal decarboxylation reaction is 100–200℃. The reaction pressure is 1–50 kg; The distillation temperature is 10–80°C, the distillation pressure is 0–5 kg, and the distillation separation reflux ratio is 10:1–0.1:1.

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