Preparation method of perfluoromethoxy methylene vinyl ether
By using ozone cracking of perfluoroolefins and subsequent reactions, the synthesis problem of trifluoromethyl fluoroformate was solved, enabling the low-cost and easily separable industrial production of perfluoromethoxymethylene vinyl ether.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 漳平市九鼎泰天科技有限公司
- Filing Date
- 2026-01-30
- Publication Date
- 2026-05-12
AI Technical Summary
The synthesis of trifluoromethyl fluoroformate in the existing technology involves the use of flammable and explosive hazardous substances, poor reaction selectivity, difficulty in controlling the product, and high equipment requirements, which makes it difficult to industrialize perfluoromethoxymethylene vinyl ether and results in high costs.
Ozone cracking reaction was carried out using perfluoroolefins as raw materials to separate and purify trifluoromethyl fluoroformate, which was then reacted with fluorine gas and halogenated olefins to generate fluorohalogenated ethers. Finally, perfluoromethoxymethylene vinyl ether was obtained by dehalogenation or hydrogen halogenation.
This invention provides a safe, reliable, and mild process method for preparing perfluoromethoxymethylene vinyl ethers, which yields easy-to-separate products and high yields, reducing raw material costs and making it suitable for industrial production.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of fluorochemical technology, and in particular to a method for preparing perfluoromethoxymethylene vinyl ether. Background Technology
[0002] MOVE (perfluoromethoxymethylene vinyl ether) is a high-performance fluorinated monomer that combines the properties of perfluoroalkyl, oxygen, and vinyl groups. It exhibits excellent resistance to high and low temperatures and corrosion, giving it unique advantages in certain applications. It is a key raw material for the synthesis of low-temperature fluororubber.
[0003] Trifluoromethyl fluoroformate is a key raw material for the preparation of perfluoromethoxymethylene vinyl ethers, but it is not easily obtained. While some patents and literature have reported on the synthesis of trifluoromethyl fluoroformate both domestically and internationally, it suffers from the following drawbacks: First, the reaction raw materials involve flammable and explosive hazardous substances such as CO, fluorine, and CF3OF, or expensive reagents that are difficult to produce on a large scale; second, the reaction selectivity is poor, the product is difficult to control, and the yield is low; third, the reaction conditions are harsh, and the product contains corrosive components, requiring highly sophisticated equipment. In summary, the industrial production of trifluoromethyl fluoroformate faces significant obstacles, making the industrial production of perfluoromethoxymethylene vinyl ethers difficult and extremely costly. Summary of the Invention
[0004] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing perfluoromethoxymethylene vinyl ether, which is suitable for the industrial production of perfluoromethoxymethylene vinyl ether.
[0005] To achieve the above objectives, the present invention provides a method for preparing perfluoromethoxymethylene vinyl ether, comprising the following steps:
[0006] S1) Trifluoromethyl fluoroformate was obtained by ozone cracking reaction of perfluoroolefins as raw materials and then separated and purified.
[0007] S2) Trifluoromethyl fluoroformate reacts with fluorine gas and haloalkenes to form fluorohalides.
[0008] S3) Fluorohalogen ethers are dehalogenated or hydrogenated to obtain perfluoromethoxymethylene vinyl ethers.
[0009] Preferably, the perfluoroolefin is hexafluoropropylene, perfluoro-2-butene, perfluoro-2-methyl-2-pentene, perfluoro-4-methyl-2-pentene, or perfluoro-3-isopropyl-4-methyl-2-pentene; more preferably, the perfluoroolefin is hexafluoropropylene, perfluoro-2-methyl-2-pentene, or perfluoro-4-methyl-2-pentene.
[0010] In some specific implementations, step S1 above includes the following process:
[0011] 1) A mixture of acyl fluorides, including trifluoromethyl fluoroformate, is obtained by ozone oxidation and cracking of perfluoroolefins;
[0012] 2) The above mixture was separated and purified to obtain trifluoromethyl fluoroformate.
[0013] 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.
[0014] Preferably, the molar ratio of the perfluoroolefin to the consumed ozone is 1:(0.1~8), more preferably 1:(0.1~5).
[0015] 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℃, -45℃, -40℃, -20℃, 0℃, 25℃, 40℃, 50℃, 60℃, or 70℃, or any of the above values as the upper or lower limit.
[0016] 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.
[0017] Furthermore, in the above-mentioned ozone decomposition reaction, a reaction regulator can be added as needed to dilute the raw materials and control the composition of the product. The reaction regulator is a proton-containing compound, preferably including alcohols and / or acidic compounds. Preferably, the reaction regulator is one or more of fluorocarbonic acid and fluorocarbon alcohols. More preferably, the fluorocarbonic acid includes one or more of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid, and the fluorocarbon alcohol includes one or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol. The mass ratio of the reaction regulator to the perfluoroolefin is preferably (0:100) to (80:20).
[0018] The above-mentioned ozone cracking reaction can be carried out in batch or continuous operation. The batch operation is preferably 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 preferably 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 being continuously added to the cracking reactor at a certain rate during the process.
[0019] The ozone decomposition reaction described above has no special limitations on the reaction time. Preferably, for batch operation, the reaction can generally be stopped after the substrate has been completely decomposed; for continuous operation, the reaction can be stopped at any time according to the actual needs of the reaction.
[0020] The present invention does not impose any particular limitation on the above separation and purification methods, and the methods can be selected according to the boiling point of the product, such as condensation treatment based on the boiling point of the product.
[0021] Furthermore, when the raw material is hexafluoropropylene, the above method for preparing trifluoromethyl fluoroformate includes the following steps:
[0022] 1) In a dry reactor, hexafluoropropylene is added, and then a mixture of oxygen and ozone is introduced to perform ozone cracking, yielding crude products including fluorocarbonyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate; or, in a dry reactor, a fluorocarbon solvent and a regulator are added, and then a mixture of hexafluoropropylene, oxygen, and ozone is introduced to perform ozone cracking, yielding crude products including fluorocarbonyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate.
[0023] 2) The crude product was separated and purified to obtain pure trifluoromethyl fluoroformate.
[0024] Further, in step 1) above, the molar ratio of hexafluoropropylene to ozone is 1:(0.1~8); preferably, the molar ratio of hexafluoropropylene to ozone is 1:(0.2~3).
[0025] 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℃.
[0026] 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.
[0027] 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.
[0028] 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).
[0029] Furthermore, in the ozone decomposition reaction, a reaction regulator can be added as needed to dilute the raw materials and control the product composition. The reaction regulator is a proton-containing compound, including alcohols and acids. Preferably, the reaction regulator is one or more of fluorocarbonic acid and fluorocarbon alcohols. More preferably, the fluorocarbonic acid includes one or more of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid, and the fluorocarbon alcohol includes one or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol. The mass ratio of the reaction 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%.
[0030] Furthermore, in step 2), since the boiling points of carbonyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate differ significantly (at -84°C, -59°C, and -35°C, respectively), the reaction products are easily separated. Typically, when hexafluoropropylene is cracked at a temperature below its boiling point (-29°C), such as -50°C, the separation and purification specifically involves: 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.
[0031] When hexafluoropropylene is cracked at a temperature above its boiling point (-29°C) such as 30°C, the separation and purification process specifically involves: the reaction products, discharged with the reaction tail gas, 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). Carbonyl fluoride and trifluoroacetyl fluoride, discharged with the reaction tail gas, are absorbed by 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 are in 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 low-temperature distillation.
[0032] Furthermore, when the raw material is perfluoro-4-methyl-2-pentene, the above method for preparing trifluoromethyl fluoroformate includes the following steps:
[0033] 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.
[0034] 2) The crude product was separated and purified to obtain pure trifluoromethyl fluoroformate.
[0035] Further, in step 1) above, the molar ratio of perfluoro-4-methyl-2-pentene to ozone is 1:(0.1~8); preferably, the molar ratio of perfluoro-4-methyl-2-pentene to ozone is 1:(0.2~3).
[0036] 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℃.
[0037] 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.
[0038] 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.
[0039] 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 one or more of 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).
[0040] Furthermore, in the ozone decomposition reaction, a reaction regulator can be added as needed to dilute the raw materials and control the product composition. The reaction regulator is a proton-containing compound, preferably including alcohols and / or acidic compounds. Preferably, the reaction regulator includes one or more of fluorocarbonic acid and fluorocarbon alcohols. More preferably, the fluorocarbonic acid includes one or more of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid, and the fluorocarbon alcohol includes one or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol. 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%.
[0041] Furthermore, in step 2) above, since the boiling points of trifluoromethyl fluoroformate, heptafluoroisobutyryl fluoride, and trifluoroacetyl fluoride differ significantly (at -35℃, -2~4℃, and -59℃, respectively), the reaction products are easily separated.
[0042] Preferably, the separation and purification specifically involves: 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; and finally passes through an ethanol absorption tank to absorb trifluoroacetyl fluoride, generating ethyl trifluoroacetate.
[0043] During the pyrolysis at -50℃, a small amount of product (trifluoroacetyl fluoride) is discharged with the reaction gas stream, while the majority of the product (heptafluoroisobutyryl fluoride and trifluoromethyl fluoroformate) is stored in the reactor. After the reaction is complete, the reactor is slowly heated and distilled. First, trifluoromethyl fluoroformate is distilled off, cooled in 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 heptafluoromethyl fluoride storage tank (controlled at -30 to 0℃). 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℃). When pyrolyzed at a relatively high 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 heptafluoroacetyl 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 the trifluoroacetyl fluoride, generating ethyl trifluoroacetate. Preferably, the trifluoromethyl fluoroformate condenser can be used in a mode where the refrigerant and reaction products do not come into contact; more preferably, the trifluoromethyl fluoroformate condenser can be used in a mode where the refrigerant and reaction products come into direct contact, in which case the refrigerant is preferably an inert fluorocarbon solvent such as perfluoroolefins, hydrofluorocarbons, hydrofluoroethers, and perfluoropolyethers.
[0044] Further, the crude trifluoromethyl fluoroformate is distilled under pressure to obtain high-purity trifluoromethyl fluoroformate. The distillation temperature is -30 to 80°C, preferably -20 to 60°C; more preferably -10 to 40°C. The pressure is 1 to 15 kg; preferably 2 to 10 kg; more preferably 3 to 8 kg.
[0045] Furthermore, when the raw material is perfluoro-2-methyl-2-pentene, the above method for preparing trifluoromethyl fluoroformate includes the following steps:
[0046] 1) In a dry reaction vessel, perfluoro-2-methyl-2-pentene is added, followed by the introduction of an oxygen-ozone mixture for ozone cracking, yielding crude products including hexafluoroacetone, pentafluoropropionyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate; or, perfluoroolefins, fluorocarbon solvents, and reaction regulators are first mixed in a certain proportion, then a portion of the mixture is added to the cracking reaction vessel at once, followed by continuous introduction of an ozone-oxygen mixture at a set temperature for cracking, with the mixture being continuously added at a certain rate during the process, yielding crude products including hexafluoroacetone, pentafluoropropionyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate.
[0047] 2) The crude product was selectively absorbed and purified to obtain pure trifluoromethyl fluoroformate.
[0048] Further, in step 1) above, the molar ratio of perfluoro-2-methyl-2-pentene to ozone is 1:(0.1~8); preferably, the molar ratio of perfluoro-2-methyl-2-pentene to ozone is 1:(0.2~3).
[0049] 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℃.
[0050] 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.
[0051] 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.
[0052] Furthermore, in the ozone decomposition reaction, the raw material perfluoro-2-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 one or more of Novec 7100, 7200, or 7500, and the perfluoropolyether is preferably Krytox GPL101, etc. The mass ratio of the solvent to perfluoro-2-methyl-2-pentene is preferably (0:100) to (80:20).
[0053] Furthermore, in the ozone decomposition reaction, a reaction regulator can be added as needed to dilute the raw materials and control the product composition. The reaction regulator is a proton-containing compound, preferably including alcohols and / or acidic compounds. Preferably, the reaction regulator includes one or more of fluorocarbonic acid and fluorocarbon alcohols. More preferably, the fluorocarbonic acid includes one or more of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid, and the fluorocarbon alcohol includes one or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol. 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%.
[0054] Further, in step 2) above, the crude product is selectively absorbed and purified by an absorbent to obtain pure trifluoromethyl fluoroformate. The specific process is as follows: the reaction product gas stream first passes through an absorbent tank (the absorbent is hydrogen fluoride) to absorb hexafluoroacetone to form a hexafluoroacetone-hydrogen fluoride complex, thereby collecting hexafluoroacetone; then it passes through a low-temperature condenser to collect trifluoromethyl fluoroformate and pentafluoropropionyl fluoride; finally, it passes through an ethanol absorption tank to absorb trifluoroacetyl fluoride to generate ethyl trifluoroacetate.
[0055] During pyrolysis at -50°C, the product (trifluoroacetyl fluoride) is discharged with the reaction gas stream, while most of the products (hexafluoroacetone, pentafluoropropionyl fluoride, and trifluoromethyl fluoroformate) are stored in the reactor. After the reaction, the reactor is slowly heated and distilled. The gas stream first passes through a selective absorbent tank (hydrogen fluoride as the absorbent, controlled at -25°C) to absorb the hexafluoroacetone, forming a hexafluoroacetone-hydrogen fluoride complex, thereby collecting the hexafluoroacetone. The remaining pentafluoropropionyl fluoride and trifluoromethyl fluoroformate gas streams are then cooled by a cryogenic condenser (controlled at -60 to -40°C) and stored in a cryogenic storage tank (controlled at -55 to -35°C). During the process, trifluoroacetyl fluoride is discharged with the reaction tail gas and absorbed by an ethanol absorption tank (controlled at -30 to 20°C). When pyrolyzed at a higher temperature above 30°C, the products hexafluoroacetone, pentafluoropropionyl fluoride, trifluoroacetyl fluoride, and trifluoromethyl fluoroformate are discharged with the reaction gas stream. Hexafluoroacetone can be absorbed by passing the gas stream sequentially through a selective absorbent tank (the absorbent is hydrogen fluoride, and the temperature is controlled at -25 to -15°C) to form a hexafluoroacetone-hydrogen fluoride complex, thereby collecting the hexafluoroacetone. Then, the gas stream is cooled at a low temperature to collect trifluoromethyl fluoroformate and pentafluoropropionyl fluoride. The remaining tail gas is passed through an ethanol absorption tank (the temperature is controlled at -30 to 20°C) to absorb trifluoroacetyl fluoride, generating ethyl trifluoroacetate. Specifically, the reaction product gas stream first passes through a selective absorbent tank (the absorbent is hydrogen fluoride, with its temperature controlled at -25 to -15°C) to absorb hexafluoroacetone, forming a hexafluoroacetone-hydrogen fluoride complex, thereby collecting the hexafluoroacetone; then, it passes through a low-temperature condenser (with its temperature controlled at -60 to -40°C) to condense pentafluoropropionyl fluoride and trifluoromethyl fluoroformate, which are then stored in a low-temperature 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 trifluoroacetate. Preferably, the condenser can be used in a mode where the refrigerant and reaction products do not come into contact; more preferably, the condenser can be used in a mode where the refrigerant and reaction products come into direct contact, in which case the refrigerant is preferably an inert fluorocarbon solvent such as perfluoroolefins, hydrofluorocarbons, hydrofluoroethers, and perfluoropolyethers.
[0056] Further, high-purity trifluoroformate is obtained by pressurized distillation of pentafluoropropionyl fluoride and crude trifluoromethyl fluoroformate. The distillation temperature is -30~80℃, preferably -20~60℃; more preferably -10~40℃. The pressure is 1~15 kg; preferably 2~10 kg; more preferably 3~8 kg.
[0057] Then, using the above-mentioned trifluoromethyl fluoroformate as a raw material, it reacts with fluorine gas and halogenated alkenes to generate fluorohalides.
[0058] In some specific implementations, step S2) includes the following steps:
[0059] 1) At low temperature, trifluoromethyl fluoroformate is mixed with haloolefin and solvent, and diluted fluorine gas is continuously introduced under stirring to react for a certain period of time.
[0060] 2) The reaction product was washed, dried and distilled to obtain pure fluorohaloether.
[0061] The haloalkene has the structure shown in formula a, and the fluorohaloether has the structure shown in formula b:
[0062] Formula a; Formula b;
[0063] In this case, X and Y are independently selected from H or halogen atoms, and not both of them are H.
[0064] The halogen atom is a chlorine atom, a bromine atom, or an iodine atom, preferably a chlorine atom.
[0065] In some specific embodiments, the haloolefin is 1,2-dichloro-1,2-difluoroethylene.
[0066] The reaction of trifluoromethyl fluoroformate with fluorine gas and halogenated olefins may or may not involve the addition of a solvent. The solvent is preferably a perhalogenated solvent, more preferably a solvent containing fluorine, chlorine, or oxygen, or having an amine group, further preferably a perfluorinated solvent, and even more preferably one or more of perfluorocarbons, perfluoropolyethers, perfluoroalkyl ethers, and perfluoroamines. In some specific embodiments, the solvent is selected from perfluorobutane.
[0067] The molar ratio of trifluoromethyl fluoroformate to haloolefin is preferably 3:1 to 1:3, more preferably 2:1 to 1:2; the molar ratio of trifluoromethyl fluoroformate to fluorine gas is 3:1 to 1:3, more preferably 2:1 to 1:2.
[0068] The mass ratio of the solvent to trifluoromethyl fluoroformate is 0:100 to 100:1, more preferably 0:50 to 50:1.
[0069] The reaction temperature is preferably -150 to -50°C, more preferably -100 to -50°C. In some specific embodiments, the reaction temperature is -100, -90, -80, -70, -60, or -50°C. The reaction pressure is preferably 0 to 1 MPa, more preferably atmospheric pressure. The reaction time is preferably 1 to 72 hours, more preferably 1 to 24 hours.
[0070] The mixing of trifluoromethyl fluoroformate with haloolefins and solvents refers to the mixing of each material in a liquid phase.
[0071] The continuous introduction of fluorine gas is preferably carried out by diluting the fluorine gas with an inert gas, preferably nitrogen or helium, and the molar concentration of the diluted fluorine gas is preferably 5% to 80%.
[0072] The washing and drying processes employ methods familiar to professionals, which will not be elaborated upon here.
[0073] In some specific implementations, ice water is added dropwise to the reaction solution containing the reaction product for washing, followed by standing and separation to separate the lower organic phase. The lower organic phase is then washed three times with cold water, dried to remove water, and then distilled to obtain pure fluorohaloether.
[0074] The temperature of the reaction solution during the addition of ice water is preferably 0~40℃, more preferably 0~25℃, and the addition time is preferably 0.5~4h, more preferably 1~2h.
[0075] The present invention does not impose any special limitation on the drying method, and can be a drying method known to those skilled in the art, including but not limited to molecular sieve or desiccant dehydration, and more preferably molecular sieve dehydration.
[0076] The pressure of the distillation is preferably -0.1 to 0.3 MPa, and more preferably atmospheric pressure. The temperature of the distillation is preferably -20 to 150°C, and more preferably 0 to 100°C.
[0077] Preferably, the remaining trifluoromethyl fluoroformate is recovered by distillation after the reaction is completed.
[0078] Finally, the above-mentioned fluorohalides are used as raw materials for dehalogenation or hydrogen halogenation.
[0079] Preferably, the dehalogenation or hydrogen halide is carried out under the action of an active metal and a reducing catalyst.
[0080] The active metal is preferably selected from zinc.
[0081] The reducing catalyst is preferably selected from zinc chloride.
[0082] The solvent used in the dehalogenation or hydrogen halide reaction is preferably an aprotic polar solvent, more preferably one or more of N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, acetonitrile, N-methylpyrrolidone, diethylene glycol dimethyl ether, tetraethylene glycol dimethyl ether, etc.
[0083] The reaction temperature is preferably 0~200℃, more preferably 0~150℃; the reaction pressure is preferably 0~1MPa, more preferably atmospheric pressure. The reaction time is preferably 1~24 hours, more preferably 1~8 hours.
[0084] The molar ratio of the fluorohalide ether to the active metal is preferably 1:1 to 50, more preferably 1:1 to 10. The molar ratio of the fluorohalide ether to the reducing catalyst is preferably 1:0.01 to 1, more preferably 1:0.1 to 1.
[0085] The mass ratio of the solvent to the fluorohalo ether is preferably 1:100-100:1, and more preferably 1:50-50:1.
[0086] In some specific implementations, the dehalogenation or hydrogen halogenation process includes the following steps:
[0087] 1) The reaction is carried out in a reaction vessel equipped with a constant pressure dropping funnel and a distillation system; under inert gas protection, solvent, zinc powder and zinc chloride are added to the reaction vessel, and stirring is started to form a suspension. After the reaction vessel is heated to the set temperature, fluorohalide ether is added dropwise while the reaction is carried out. At the same time, the crude product is collected by the distillation system. After the dropwise addition is completed, the temperature is continued to rise for a period of time. The reaction is stopped when the raw material fluorohalide ether has reacted completely.
[0088] 2) The crude product collected in step 1) is further distilled to obtain pure perfluoromethoxymethylene vinyl ether.
[0089] The perfluoromethoxymethylene vinyl ether has the following structure:
[0090]
[0091] The dripping time is preferably 1 to 4 hours, and more preferably 1 to 2 hours.
[0092] Preferably, the distillation system in step 1) simultaneously collects the crude product, that is, the crude product is collected while the reaction is underway. The reflux condenser temperature is preferably 0~30℃, and the temperature of the distillation condenser and receiving tank is preferably -50~-30℃.
[0093] Step 2) The pressure of the distillation is preferably 0.1~1 MPa, more preferably 0.1~0.5 MPa. The temperature of the distillation is preferably 0~150℃, more preferably 0~80℃.
[0094] Compared with the prior art, the present invention provides a method for preparing perfluoromethoxymethylene vinyl ether, comprising the following steps: S1) using a perfluoroolefin of Formula I as a raw material for ozone cracking reaction, followed by separation and purification to obtain trifluoromethyl fluoroformate; S2) reacting trifluoromethyl fluoroformate with fluorine gas and halogenated olefin to generate fluorohalogenated ether; S3) the fluorohalogenated ether is dehalogenated or hydrogenated to obtain perfluoromethoxymethylene vinyl ether.
[0095] The technical solution provided by this invention has the following advantages: 1) Low raw material cost. The main raw material for the preparation of trifluoromethyl fluoroformate is fluorinated olefin, which has been industrialized; 2) Mild, simple and safe process conditions; 3) Good reaction selectivity, easy product separation and high yield; 4) The perfluoromethoxymethylene vinyl ether prepared by this invention has low cost and is suitable for industrial scale-up production. Detailed Implementation
[0096] To further illustrate the present invention, a detailed description is provided below with reference to embodiments. However, it should be understood that these descriptions are merely for further illustrating the features and advantages of the present invention, and not for limiting the scope of the claims.
[0097] There are no particular restrictions on the source of any raw materials used in this invention; they can be purchased from the market or prepared using conventional methods known to those skilled in the art.
[0098] Example 1
[0099] Ozone decomposition of hexafluoropropylene
[0100] 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.
[0101] 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 96 hours. The trifluoromethyl fluoroformate tank collected 1267g of trifluoromethyl fluoroformate, with a yield of 48%. 19 F NMR (400 MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Approximately 696 g of trifluoroacetyl fluoride was collected in the cryogenic condenser, yielding 30%. 19F NMR (400 MHz) δ -9.5 (s, 1F), -79.5 (s, 3F). 1252 g of diethyl carbonate was collected in an ethanol absorption vessel, corresponding to 700 g of carbamate, yield 53%.
[0102] Example 2
[0103] ozone cracking of perfluoro-4-methyl-2-pentene
[0104] 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.
[0105] 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 residual tail gas is directly vented. After the reaction is complete, 3009 g of heptafluoroisobutyryl fluoride is collected, with a yield of 76%. 19 F NMR (400 MHz) δ 28 (s, 1F), -78.9 (d, 6F), -185 (m, 1F). Trifluoromethyl fluoroformate 1669.5 g, yield 69%. 19 F NMR (400 MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). Ethyl trifluoroacetate 625 g, yield 24%. 19 F NMR (400 MHz) δ -80.5 (s, 3F); 1 H NMR (400 MHz, CDCl3) δ 1.4 (t, 3H), 4.4 (q, 2H).
[0106] Example 3
[0107] ozone cracking of perfluoro-2-methyl-2-pentene
[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, 2 kg of trifluoroacetic acid was added, followed by 3 kg of perfluoro-2-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-2-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-2-methyl-2-pentene was added. The reaction was stopped after 144 hours. During the reaction, the product gas stream first passes through an anhydrous hydrogen fluoride absorption tank (containing 1 kg of anhydrous hydrogen fluoride and controlled at -25°C), where most of the hexafluoroacetone is absorbed to form a hexafluoroacetone-hydrogen fluoride complex, which is stored in the hydrogen fluoride absorption tank. Then, it passes through a trifluoromethyl fluoroformate condenser (controlled at -55°C), where most of the trifluoromethyl fluoroformate and pentafluoropropionyl fluoride are 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, 2616.8 g of hexafluoroacetone is collected, with a yield of 86%. 19 F NMR (400 MHz) δ -86.8 (d, 6F). 1330.8 g of trifluoromethyl fluoroformate was collected, yield 55%. 19 F NMR (400 MHz) δ -20.5 (s, 1F), -65.5 (s, 3F). 943.3 g of pentafluoropropionyl fluoride was collected, yield 31%. 19 F NMR (400 MHz) δ 18.9 (s, 1F), -87.4 (t, 3F), -125.4 (q, 2F). 728.8 g of ethyl trifluoroacetate was collected, yield 28%. 19 F NMR (400 MHz) δ -80.5 (s, 3F); 1 H NMR (400 MHz, CDCl3) δ 1.4 (t, 3H), 4.4 (q, 2H).
[0110] Example 4
[0111] Distillation of trifluoromethyl fluoroformate
[0112] Distillation was carried out in a 1L distillation column system. Before feeding, the distillation system was heated to 120°C and evacuated for 2 hours to remove water. Then, nitrogen was introduced and the pressure was maintained down to -30°C. Vacuum was then applied, and 528g of cryogenically liquefied trifluoromethyl fluoroformate was added to the distillation system. Nitrogen gas at 0.5MPa was introduced into the distillation column reboiler. The condenser temperature was maintained at -25°C, and the 1L receiving tank temperature was maintained at approximately -5°C. Total reflux was initiated. The reboiler temperature was slowly raised to 50°C, the pressure inside the reboiler was approximately 0.7MPa, and the reflux ratio was adjusted to 10:1. Collection began, and 475g of trifluoromethyl fluoroformate was collected in the receiving tank, with a yield of 90%. GC testing showed a purity of 99%.
[0113] Example 5
[0114] Trifluoromethyl fluoroformate reacts with 1,2-dichloro-1,2-difluoroethylene and fluorine gas.
[0115] The reaction was carried out in a 1L Monel reactor 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 -80°C.
[0116] Under nitrogen protection, 152g of 1,2-dichloro-1,2-difluoroethylene was added to the reactor, followed by 132g of trifluoromethyl fluoroformate. When the material temperature cooled to -80℃, stirring was started. Fluorine gas diluted with nitrogen (fluorine content 20%) was metered and introduced at -80℃ using a gas mass flow meter at a flow rate of 224 sccm. The reaction was carried out while the fluorine gas was introduced. After 4 hours, the introduction of fluorine gas was stopped, and the reaction was continued for another 2 hours to finish.
[0117] The reactor is heated to 30°C and the gas is vented. The unreacted raw materials are condensed in a condenser (-50°C) and stored in a collection tank (-40°C) to recover the raw materials trifluoromethyl fluoroformate and 1,2-dichloro-1,2-difluoroethylene.
[0118] The residue in the reactor was released, and ice water (80g) was slowly added for extraction and allowed to stand for separation. The lower organic phase was washed and extracted three times with cold water at 5°C, and then dried through a 4A molecular sieve and distilled to obtain 245g of pure fluorohalogen ether with a yield of 81% and a purity of 99%.
[0119] Example 6
[0120] Trifluoromethyl fluoroformate reacts with 1,2-dichloro-1,2-difluoroethylene and fluorine gas.
[0121] The reaction was carried out in a 1L Monel reactor 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 -80°C.
[0122] Under nitrogen protection, 500g of perfluorobutane and 152g of 1,2-dichloro-1,2-difluoroethylene were added to the reactor, followed by 132g of trifluoromethyl fluoroformate. When the material temperature cooled to -80℃, stirring was started. Fluorine gas diluted with nitrogen (fluorine content 20%) was metered and introduced at -80℃ using a gas mass flow meter at a flow rate of 224 sccm. The reaction was carried out while the fluorine gas was introduced. After 4 hours, the introduction of fluorine gas was stopped, and the reaction was continued for another 2 hours to finish.
[0123] The reactor is heated to 30°C and the gas is vented. The unreacted raw materials are condensed in a condenser (-50°C) and stored in a collection tank (-40°C) to recover the raw materials trifluoromethyl fluoroformate, 1,2-dichloro-1,2-difluoroethylene and all perfluorobutane.
[0124] The residue in the reactor was released, and ice water (80g) was slowly added for extraction and allowed to stand for separation. The lower organic phase was washed and extracted three times with cold water at 5°C, and then dried through a 4A molecular sieve and distilled to obtain 270g of pure fluorohalogen ether with a yield of 89% and a purity of 99%.
[0125] Example 7
[0126] Trifluoromethyl fluoroformate reacts with 1,2-dichloro-1,2-difluoroethylene and fluorine gas.
[0127] The reaction was carried out in a 1L Monel reactor 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 -60°C.
[0128] Under nitrogen protection, 152g of 1,2-dichloro-1,2-difluoroethylene was added to the reactor, followed by 132g of trifluoromethyl fluoroformate. When the material temperature cooled to -60℃, stirring was started. Fluorine gas diluted with nitrogen (fluorine content 20%) was metered and introduced at -60℃ using a gas mass flow meter at a flow rate of 224 sccm. The reaction was carried out while the fluorine gas was introduced. After 4 hours, the introduction of fluorine gas was stopped, and the reaction was continued for another 2 hours to finish.
[0129] The reactor is heated to 30°C and the gas is vented. The unreacted raw materials are condensed in a condenser (-50°C) and stored in a collection tank (-40°C) to recover the raw materials trifluoromethyl fluoroformate and 1,2-dichloro-1,2-difluoroethylene.
[0130] The residue in the reactor was released, and ice water (80g) was slowly added for extraction. The mixture was allowed to stand and separate into layers. The lower organic phase was washed and extracted three times with cold water at 5°C. Then, it was dried through a 4A molecular sieve and distilled to obtain 273g of pure fluorohalogen ether with a yield of 90% and a purity of 99%.
[0131] Example 8
[0132] Dehalogenation of fluorohalides
[0133] The reaction was carried out in a 1L Monel reactor 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 system cooled to room temperature.
[0134] The reactor was stirred and, under nitrogen protection, 500g of N,N-dimethylformamide, 65g of zinc powder, and 13.6g of zinc chloride were added sequentially. The temperature of the reflux condenser was controlled at 15℃, and the temperature of the reaction product condenser and collection tank was controlled at -40℃. The reactor was heated to 70℃, and 151g of fluorohaloether was slowly added dropwise while reacting. The addition was completed after 2 hours, and the reaction was continued at 70℃ for 1 hour. Then, the temperature was raised to 120℃ and the reaction was continued for another hour before the reaction was stopped.
[0135] The crude perfluoromethoxymethylene vinyl ether collected in the distillation tank yielded 107 g of pure perfluoromethoxymethylene vinyl ether, with a yield of 92% and a purity of 99%. 19 F NMR (400 MHz) δ -59.2 (s, 2F), -63.5 (s, 3F), -116.3 (m, 1F), -124.2 (m, 1F), -139.7 (m, 1F).
[0136] Example 9
[0137] Dehalogenation of fluorohalides
[0138] The reaction was carried out in a 1L Monel reactor 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 system cooled to room temperature.
[0139] The reactor was stirred and, under nitrogen protection, 500g of diethylene glycol dimethyl ether, 65g of zinc powder, and 13.6g of zinc chloride were added sequentially. The temperature of the reflux condenser was controlled at 15℃, and the temperature of the reaction product condenser and collection tank was controlled at -40℃. The reactor was heated to 70℃, and 151g of fluorohalogen ether was slowly added dropwise while reacting. The addition was completed after 2 hours, and the reaction was continued at 70℃ for 1 hour. Then, the temperature was raised to 120℃ and the reaction was continued for another hour before the reaction was stopped.
[0140] The crude perfluoromethoxymethylene vinyl ether collected in the distillation tank yielded 101g of pure perfluoromethoxymethylene vinyl ether, with a yield of 87% and a purity of 99%.
[0141] 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 a perfluoromethoxymethylene vinyl ether, comprising the following steps: S1) Trifluoromethyl fluoroformate was obtained by ozone cracking reaction of perfluoroolefins as raw materials and then separated and purified. S2) Trifluoromethyl fluoroformate reacts with fluorine gas and haloalkenes to form fluorohalides. S3) Fluorohalogen ethers are dehalogenated or hydrogenated to obtain perfluoromethoxymethylene vinyl ethers.
2. The preparation method according to claim 1, characterized in that, The perfluoroolefin is hexafluoropropylene, perfluoro-2-butene, perfluoro-2-methyl-2-pentene, perfluoro-4-methyl-2-pentene, or perfluoro-3-isopropyl-4-methyl-2-pentene.
3. The preparation method according to claim 1, characterized in that, The molar ratio of the perfluoroolefin to ozone is 1:(0.1~8). The temperature of the ozone decomposition reaction is -100℃ to 100℃; The pressure of the ozone decomposition reaction is 1 to 10 kg.
4. The preparation method according to claim 1, characterized in that, A reaction modifier is added during the ozone decomposition reaction; The reaction modifiers include alcohols and / or acidic compounds.
5. The preparation method according to claim 4, characterized in that, The reaction regulator includes one or more of fluorocarbons and fluorocarbon alcohols; The mass ratio of the reaction regulator to the perfluoroolefin is (0:100) to (80:20).
6. The preparation method according to claim 5, characterized in that, The fluorocarbonic acid includes one or more of trifluoroacetic acid, pentafluoropropionic acid, and heptafluorobutyric acid. The fluorocarbon alcohols include one or more of trifluoroethanol, tetrafluoropropanol, pentafluoropropanol, hexafluoroisopropanol, and octafluoropentanol.
7. The preparation method according to claim 1, characterized in that, In step S2), the haloalkene has the structure shown in formula a, and the fluorohaloether has the structure shown in formula b. Formula a; Formula b; In this case, X and Y are independently selected from H or halogen atoms, and not both of them are H.
8. The preparation method according to claim 1, characterized in that, In step S2), the solvent for the reaction is selected from a fully halogenated solvent; The molar ratio of trifluoromethyl fluoroformate to haloolefin is 3:1 to 1:3; The reaction temperature is -150 to -50°C.
9. The preparation method according to claim 1, characterized in that, The dehalogenation or hydrogen halide is carried out under the action of an active metal and a reducing catalyst.
10. The preparation method according to claim 9, characterized in that, The active metal is selected from zinc; The reducing catalyst is selected from zinc chloride.