Method and device for removing peroxide in perfluoropolyether and co-producing and preparing trifluoroacetyl fluoride

Abstract

The invention discloses a device for removing peroxide in perfluoropolyether and co-producing trifluoroacetyl fluoride, which is characterized in that an output port (16) at the top of a peroxide removal kettle (1) is communicated with an input port (17) at the bottom of a precooler (2) through a pipeline I (15), and an output port (18) at the top of the precooler (2) is communicated with an input port (20) at the top of a condenser (3) through a pipeline II (19); and an output port (20) at the bottom of the condenser (3) is connected with the purification device through a pipeline III (21). The invention also provides a method for removing peroxides in perfluoropolyether and co-producing trifluoroacetyl fluoride, the trifluoroacetyl fluoride with high purity can be separated, and the method and the device not only can ensure the installability of perfluoropolyether in use, but also can be used for preparing the trifluoroacetyl fluoride. The perfluoropolyether peroxide generated in the process of removing the peroxide in the perfluoropolyether can be recycled, and the trifluoroacetyl fluoride with very high purity is prepared.

Description

Technical Field

[0001] This invention relates to a method and apparatus for preparing trifluoroacetyl fluoride, a chemical raw material, and particularly to a method and apparatus for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride. Background Technology

[0002] For Y-type perfluoropolyethers, peroxides are inevitably generated during the production process and decompose upon heating; if they are not removed... These Peroxide bonds pose safety hazards when using perfluoropolyethers. The removal of peroxides from perfluoropolyethers is generally achieved through heating, which simultaneously produces other acyl fluoride byproducts such as perfluoroformyl fluoride and trifluoroacetyl fluoride. Trifluoroacetyl fluoride, in particular, is an important fluorine-containing intermediate used in electronic cleaning, etching, pesticide intermediates, and fluorine-containing material monomers. Its derivatives also have wide applications, including the production of trifluoroacetic acid, an important organic synthesis reagent, and perfluoroethyl vinyl ether, a fluorine material intermediate. However, the purity of trifluoroacetyl fluoride obtained during the peroxide removal process of perfluoropolyethers is generally low, typically only 65%-80%. Some methods require the use of alumina / chromium and zinc chloride catalysts, but these are easily deactivated by anhydrous hydrogen fluoride, and the reaction temperature is high, reaching 300°C. The preparation process is complex and prone to hazards and environmental pollution. Furthermore, methods using trifluoroacetic acid fluorination and trifluoroacetic acid derivative decomposition generally only achieve a purity of around 65%, resulting in significant waste. Summary of the Invention

[0003] This invention provides a method and apparatus for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride. It not only ensures the installation of perfluoropolyethers but also allows for the recycling of perfluoropolyether peroxides generated during the removal process, thereby preparing trifluoroacetyl fluoride with high purity.

[0004] The present invention adopts the following technical solution: an apparatus for removing peroxides from perfluoropolyether and producing trifluoroacetyl fluoride, comprising a deoxygenation reactor, a precooler, a condenser and a purification device. The top output port of the deoxygenation reactor is connected to the bottom input port of the precooler through pipeline I. The top output port of the precooler is connected to the top input port of the condenser through pipeline II. The bottom output port of the condenser is connected to the purification device through pipeline III.

[0005] Furthermore, the exterior of the deoxidation reactor of the present invention is an infrared heating reactor body, which is made of SS304 stainless steel, SS316L stainless steel, SS904L stainless steel or C276 stainless steel. A deoxidation reactor agitator is provided in the middle of the infrared heating reactor body. The deoxidation reactor agitator includes a drive motor, which is located at the top of the infrared heating reactor body. The output end of the drive motor is vertically downward and connected to the upper end of the stirring shaft. The lower section of the stirring shaft is connected to the stirring blades. The stirring blades are located at the bottom of the infrared heating reactor body. The drive motor drives the stirring blades to rotate through the stirring shaft. The stirring blades are self-priming stirring blades.

[0006] Furthermore, the collection and purification device of the present invention includes a distillation column, a high-pressure stainless steel collection bottle, a storage tank, and an alkaline washing tank. The output port at the bottom of the condenser is connected to the inlet on the side of the distillation column through pipeline III. The top outlet of the distillation column is connected to the inlet of the high-pressure stainless steel collection bottle through pipeline IV. The outlet of the high-pressure stainless steel collection bottle is connected to the storage tank. The side outlet of the distillation column is connected to the alkaline washing tank through pipeline V.

[0007] Furthermore, the pressure of the distillation column of the present invention is 0.1-2.0 MPa, the top temperature of the distillation column is -60 to 15°C, and the distillation column is filled with packing material distributed from top to bottom. The packing material is metal Dixon packing, metal Pall ring packing or metal structured packing, and the packing height is 5-10 m.

[0008] This invention also discloses a method for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride, comprising the following steps: First, the perfluoropolyether containing peroxide bonds is added to a deperoxide reactor, and the deperoxide reactor is heated to 150-250°C. Then, the perfluoropolyether containing peroxide bonds is stirred in the heated deperoxide reactor using a stirrer. During the stirring process, the peroxide bonds of the perfluoropolyether decompose, thereby releasing active free radicals containing terminal oxygen groups, wherein the terminal groups have branches. The active free radical of CF3 undergoes β-fracture to form a free radical without terminal oxygen and trifluoroacetyl fluoride. The active free radical of CF3 without terminal branches releases oxygen free radicals. These free radicals complete deoxygenation through coupling. Finally, the gaseous material generated by deoxygenation is pre-cooled by a precooler and then separated into gas and liquid phases. The liquid phase recovers part of the perfluoropolyether, and the remaining gas phase is condensed by a condenser to obtain crude trifluoroacetyl fluoride. Then, the crude trifluoroacetyl fluoride is purified by a purification device to obtain trifluoroacetyl fluoride with a purity of 99%.

[0009] Furthermore, the peroxide value of the perfluoropolyether of this invention is 1-5 g / 100 g.

[0010] Furthermore, the perfluoropolyether of this invention is a Y-type perfluoropolyether prepared by photo-oxidative polymerization with a peroxide value of 2.8 mmol / kg or a Y-type perfluoropolyether prepared by photo-oxidative polymerization with a peroxide value of 1.62 mmol / kg. The structural formula of the peroxide of the Y-type perfluoropolyether is: CF3[CF(CF3)CF2O]nCF(CF3)CF2OOCF2(CF3)CF[OCF2(CF3)CF]mCF3, where n and m are integers between 0 and 10.

[0011] Furthermore, the stirring speed of the deaerator stirrer described in this invention is 100-400 rpm.

[0012] Furthermore, the cooling temperature of the precooler described in this invention is -10 to -10°C, and the condensing temperature of the condenser is -70°C.

[0013] Furthermore, the method of collecting and purifying trifluoroacetyl fluoride in this invention involves condensing the crude trifluoroacetyl fluoride and then feeding it into the side of a distillation column in the purification device. The waste gas contained in the crude trifluoroacetyl fluoride is then separated from the trifluoroacetyl fluoride by the packing material inside the distillation column. The trifluoroacetyl fluoride is then cooled to a liquid state by a -35°C refrigerant at the top of the distillation column. The cooled trifluoroacetyl fluoride is then discharged from the top outlet of the distillation column into a high-pressure stainless steel collection bottle for weighing and purity analysis by chromatography. The perfluoropolyether gas in the high-pressure stainless steel collection bottle is then discharged into a storage tank for storage. Simultaneously, the separated waste gas is discharged through the side outlet of the distillation column into an alkaline washing tank, where it is absorbed and discharged by NaOH solution. The peroxide value of the discharged product is measured to be 0.08 mmol / kg using iodometric titration.

[0014] The present invention has the following beneficial effects: After adopting the method and equipment of the present invention, the present invention can not only ensure the installation of perfluoropolyether, but also recycle the perfluoropolyether peroxide generated during the removal of peroxide in perfluoropolyether, and prepare trifluoroacetyl fluoride with high purity. Since trifluoroacetyl fluoride has high application value, this reduces the production cost of perfluoropolyether, reduces wastewater and waste gas emissions, and reduces environmental damage. The structure of the equipment is relatively simple, which reduces the preparation cost. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1This is a schematic diagram of the structure of the present invention. Detailed Implementation

[0017] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0018] exist Figure 1 This invention provides an apparatus for removing peroxides from perfluoropolyethers and simultaneously producing trifluoroacetyl fluoride. It includes a deoxygenation reactor 1, a precooler 2, a condenser 3, and a purification device. The top output port 16 of the deoxygenation reactor 1 is connected to the bottom input port 17 of the precooler 2 via pipe I 15. The top output port 18 of the precooler 2 is connected to the top input port 20 of the condenser 3 via pipe II 19. The bottom output port 20 of the condenser 3 is connected to the purification device via pipe III 21. In a preferred embodiment of the present invention, the deoxygenation reactor 1 is externally formed by an infrared-heated reactor body 11. The infrared-heated reactor body 11 is made of SS304 stainless steel, SS316L stainless steel, SS904L stainless steel, or C276 stainless steel. A deoxygenation reactor agitator is provided in the middle of the infrared-heated reactor body 11. The deoxygenation reactor agitator includes a drive motor 12, which is located at the top of the infrared-heated reactor body 11. The output end of the drive motor 12 is vertically downward and connected to the upper end of a stirring shaft 13. The lower section of the stirring shaft 13 is driven to a stirring blade 14. The stirring blade 14 is located at the bottom of the infrared-heated reactor body 11. The drive motor 12 drives the stirring blade 14 to rotate through the stirring shaft 13. The stirring blade 14 is a self-priming stirring blade. In another preferred embodiment of the present invention, the collection and purification device includes a distillation column 4. The distillation column 4 consists of a high-pressure stainless steel collecting bottle 6, a storage tank 7, and an alkaline washing tank 10. The pressure of the distillation column 4 is 0.1-2.0 MPa, and the top temperature of the distillation column 4 is -60 to -15℃. The distillation column 4 is filled with packing material 5 from top to bottom. The packing material 5 is metal Dixon packing, metal Pall ring packing, or metal structured packing. The optimal configuration is that the pressure of the distillation column 4 is 1.0 MPa, the top temperature of the distillation column 4 is -35℃, the packing material 5 is metal Pall ring packing, and the height of the packing material 5 is 5m. The output port 20 at the bottom of the condenser 3 is connected to the inlet on the side of the distillation column 4 through pipe III 21. The top outlet 8 of the distillation column 4 is connected to the inlet of the high-pressure stainless steel collecting bottle 6 through pipe IV 22. The outlet of the high-pressure stainless steel collecting bottle 6 is connected to the storage tank 7. The side outlet 9 of the distillation column 4 is connected to the alkaline washing tank 10 through pipe V 23.

[0019] This invention also discloses a method for preparing trifluoroacetyl fluoride using an apparatus for removing peroxides from perfluoropolyethers and co-producing trifluoroacetyl fluoride. The method includes the following steps: First, a perfluoropolyether containing peroxide bonds is added to a de-peroxide reactor 1. The peroxide value of the perfluoropolyether is 1-5 g / 100 g. Preferably, the perfluoropolyether is a Y-type perfluoropolyether prepared by photo-oxidative polymerization with a peroxide value of 2.8 mmol / kg or a Y-type perfluoropolyether prepared by photo-oxidative polymerization with a peroxide value of 1.62 mmol / kg. The volume of the Y-type perfluoropolyether in the infrared-heated reactor body 11 of the de-peroxide reactor 1 is 5%-50%, with a preferred configuration of 10%. This allows for sufficient gas phase space to be left, allowing for evacuation to remove air and preventing the presence of non-condensable gases that are difficult to condense. The structural formula of the peroxide in the Y-type perfluoropolyether is: CF3[CF(CF3)CF2O]nCF(CF3)CF2OOCF2(CF3)CF[OCF2(CF3)CF]mCF3, where n and m are integers between 0 and 10. Then, the deoxidizing reactor (1) is heated to 150-250°C, and the pressure is increased to 0.5-5.0 MPa. The preferred embodiment of this invention is to heat the deoxidizing reactor 1 to 150°C or 155°C, and increase the pressure to 2.0 MPa. Then, the perfluoropolyether containing peroxide bonds is stirred in the heated deoxidizing reactor 1 using a stirrer. The stirring speed of the stirrer is 100-400 rpm, preferably 200 rpm. During the stirring process, the perfluoropolyether... The peroxide bonds decompose, releasing reactive free radicals containing terminal oxygen groups. Among these, the reactive free radicals with branched CF3 end groups undergo β-splitting to form a free radical without terminal oxygen groups and trifluoroacetyl fluoride. The reactive free radicals without branched CF3 end groups release oxygen free radicals. These free radicals complete deperoxide removal through coupling. Finally, the gaseous material generated from deperoxide removal is pre-cooled in pre-cooler 2 and then subjected to gas-liquid phase separation. A portion of the perfluorinated polyether is recovered from the liquid phase. The cooling temperature of pre-cooler 2 in this invention is -10 to -10℃. The condensing temperature of condenser 3 is -70℃, and the preferred option is that the cooling temperature of precooler 2 is 0℃. The remaining gas phase is condensed by condenser 3 to obtain crude trifluoroacetyl fluoride. Then, the crude trifluoroacetyl fluoride is purified by a purification device to obtain trifluoroacetyl fluoride with a purity of 99%. The purification method is to collect the crude trifluoroacetyl fluoride after condensation and send it to the side of the distillation column 4 of the purification device. Then, the waste gas contained in the crude trifluoroacetyl fluoride is separated from the trifluoroacetyl fluoride by the packing 5 in the distillation column 4. Then, the trifluoroacetyl fluoride enters the... The -35°C refrigerant introduced into the top of distillation column 4 is cooled into a liquid state. The cooled trifluoroacetyl fluoride is then discharged from the top outlet 8 of distillation column 4 into a high-pressure stainless steel collection bottle 6, where its weight is measured and its purity is analyzed by chromatography. The perfluoropolyether gas in the high-pressure stainless steel collection bottle 6 is then discharged into a storage tank 7 for storage. At the same time, the separated waste gas enters an alkaline washing tank 10 through the side outlet 9 of distillation column 4 and is absorbed and discharged by the NaOH solution in the alkaline washing tank 10. The peroxide value of the discharged product is measured to be 0.08 mmol / kg by iodometric titration.

[0020] The process of deperoxidizing Y-type perfluoropolyether peroxide to produce trifluoroacetyl fluoride in this invention is as follows: CF3[CF(CF3)CF2O]nCF(CF3)CF2OOCF2(CF3)CF[OCF2(CF3)CF]mCF3 → CF3[CF(CF3)CF2O]nCF(CF3)CF2O·+·OCF2(CF3)CF[OCF2(CF3)CF]mCF3, (1) CF3[CF(CF3)CF2O]nCF(CF3)CF2O ·→CF3[CF(CF3)CF2O]nCF2·+CF3CFO, (2) CF3[CF(CF3)CF2O]mCF(CF3)CF2O ·→CF3[CF(CF3)CF2O]mCF2·+CF3CFO, (3) CF3[CF(CF3) CF2O]nCF2·+ CF3[CF(CF3)CF2O]m CF2·→ CF3[CF(CF3)CF2O]nCF2CF2(CF3)CF[OCF2(CF3)CF]mCF3, (4) Where n and m are integers between 0 and 10; When the temperature of the perfluoropolyether peroxide is heated to its autothermal decomposition temperature, two active free radicals 1 are released from its interior. The active free radical with branched CF3 at the end undergoes β-fracture to obtain an active free radical without branched CF3 at the end, and trifluoroacetyl fluoride 2 and 3. The active free radical without branched CF3 at the end simultaneously couples to complete the deperoxide 4.

[0021] The present invention will be further illustrated through two embodiments.

[0022] Example 1: Five kilograms of Y-type perfluoropolyether, prepared by photo-oxidative polymerization with a peroxide value of 2.8 mmol / kg, were placed in a 50L infrared-heated reactor 11, which was equipped with a deoxygenation agitator. The temperature inside the reactor was controlled to 150°C, and the Y-type perfluoropolyether containing peroxide bonds began to undergo deoxygenation. The pressure and temperature gradually increased, and after 30 minutes, the temperature was lowered to room temperature. Sampling analysis revealed that the gas phase contained 14% trifluoroacetyl fluoride. The infrared-heated reactor 11 was then opened, and the gaseous material generated from deoxygenation was introduced into a precooler 2. The temperature of the precooler 2 was lowered to 0°C for gas-liquid phase separation. Part of the perfluoropolyether was recovered from the liquid phase, and the remaining gaseous phase was condensed in a condenser 3 to obtain crude trifluoroacetyl fluoride. The condenser was cooled to -7°C. At 0℃, crude trifluoroacetyl fluoride is fed into distillation column 4. The waste gas contained in the crude trifluoroacetyl fluoride is then separated from the trifluoroacetyl fluoride by the packing 5 in distillation column 4. The trifluoroacetyl fluoride is then cooled into a liquid state by a -35°C refrigerant at the top of distillation column 4. The cooled trifluoroacetyl fluoride is then discharged from the top outlet 8 of distillation column 4 into a high-pressure stainless steel collection bottle 6, with a measured weight of 860g and a purity of 99.5% by chromatographic analysis. The perfluoropolyether gas in the high-pressure stainless steel collection bottle 6 is then discharged into a storage tank 7 for storage. At the same time, the separated waste gas is discharged from the side outlet 9 of distillation column 4 into an alkaline washing tank 10, where it is absorbed and discharged by a 15% NaOH solution. The measured weight is 3.75kg, and the peroxide value of the product is 0.18mmol / kg by iodometric titration.

[0023] Example 2: Five kilograms of Y-type perfluoropolyether, prepared by photo-oxidative polymerization with a peroxide value of 1.62 mmol / kg, were placed in a 50L infrared-heated reactor 11. The reactor 11 was equipped with a deoxygenation agitator. The temperature inside the reactor was controlled to 155°C. The Y-type perfluoropolyether containing peroxide bonds began to undergo deoxygenation within the reactor 11, with pressure and temperature gradually increasing. After 30 minutes, the temperature was lowered to room temperature. Sampling analysis revealed that the gas phase contained 8.2% trifluoroacetyl fluoride. The infrared-heated reactor 11 was then opened, and the resulting gaseous material from the deoxygenation process was introduced into a precooler 2. The precooler 2 was cooled to 0°C for gas-liquid phase separation. Part of the perfluoropolyether was recovered from the liquid phase, and the remaining gaseous phase was condensed in a condenser 3 to obtain crude trifluoroacetyl fluoride. The condenser was cooled to - At 70℃, the crude trifluoroacetyl fluoride is fed into distillation column 4. The waste gas contained in the crude trifluoroacetyl fluoride is then separated from the trifluoroacetyl fluoride by the packing material 5 in distillation column 4. The trifluoroacetyl fluoride is then cooled into a liquid state by a -35°C refrigerant at the top of distillation column 4. The cooled trifluoroacetyl fluoride is then discharged from the top outlet 8 of distillation column 4 into a high-pressure stainless steel collection bottle 6, with a measured weight of 482g and a purity of 99.5% by chromatographic analysis. The perfluoropolyether gas in the high-pressure stainless steel collection bottle 6 is then discharged into a storage tank 7 for storage. At the same time, the separated waste gas is discharged from the side outlet 9 of distillation column 4 into an alkaline washing tank 10, where it is absorbed and discharged by a 15% NaOH solution. The measured weight is 4.06kg, and the peroxide value of the product is 0.08mmol / kg by iodometric titration.

[0024] Not limited to this, any variations or substitutions conceived without inventive effort should be included within the scope of protection of this invention. Therefore, the scope of protection of this invention should be determined by the scope defined in the claims.

Claims

1. An apparatus for removing peroxides from perfluoropolyethers and co-producing trifluoroacetyl fluoride, characterized in that it It includes a deoxygenation reactor (1), a precooler (2), a condenser (3) and a purification device. The top output port (16) of the deoxygenation reactor (1) is connected to the bottom input port (17) of the precooler (2) through pipe I (15). The top output port (18) of the precooler (2) is connected to the top input port (20) of the condenser (3) through pipe II (19). The bottom output port (20) of the condenser (3) is connected to the purification device through pipe III (21).

2. The apparatus for removing peroxides from perfluoropolyethers and co-producing trifluoroacetyl fluoride according to claim 1, characterized in that: The exterior of the deoxygenation reactor (1) is an infrared heating reactor body (11). The infrared heating reactor body (11) is made of SS304 stainless steel, SS316L stainless steel, SS904L stainless steel or C276 stainless steel. A deoxygenation reactor agitator is provided in the middle of the infrared heating reactor body (11). The deoxygenation reactor agitator includes a drive motor (12). The drive motor (12) is located at the top of the infrared heating reactor body (11). The output end of the drive motor (12) is vertically downward connected to the upper end of the stirring shaft (13). The lower section of the stirring shaft (13) is connected to the stirring blade (14) for driving. The stirring blade (14) is located at the bottom of the infrared heating reactor body (11). The drive motor (12) drives the stirring blade (14) to rotate through the stirring shaft (13). The stirring blade (14) is a self-priming stirring blade.

3. The apparatus for removing peroxides from perfluoropolyethers and co-producing trifluoroacetyl fluoride according to claim 1, characterized in that: The collection and purification device includes a distillation column (4), a high-pressure stainless steel collection bottle (6), a storage tank (7), and an alkaline washing tank (10). The output port (20) at the bottom of the condenser (3) is connected to the inlet on the side of the distillation column (4) through pipeline III (21). The top outlet (8) of the distillation column (4) is connected to the inlet of the high-pressure stainless steel collection bottle (6) through pipeline IV (22). The outlet of the high-pressure stainless steel collection bottle (6) is connected to the storage tank (7). The side outlet (9) of the distillation column (4) is connected to the alkaline washing tank (10) through pipeline V (23).

4. The apparatus for removing peroxides from perfluoropolyethers and co-producing trifluoroacetyl fluoride according to claim 3, characterized in that: The pressure of the distillation column (4) is 0.1-2.0 MPa, the top temperature of the distillation column (4) is -60--15℃, and the packing (5) is distributed from top to bottom in the distillation column (4). The packing (5) is metal Dixon packing, metal Pall ring packing or metal structured packing, and the height of the packing (5) is 5-10m.

5. A method for removing peroxides from perfluoropolyethers and simultaneously preparing trifluoroacetyl fluoride, characterized in that... It includes the following steps: First, the perfluoropolyether containing peroxide bonds is added to the deoxidation reactor (1), and the deoxidation reactor (1) is heated to 150-250℃. Then, the perfluoropolyether containing peroxide bonds is stirred in the heated deoxidation reactor (1) using a stirrer. During the stirring process, the peroxide bonds of the perfluoropolyether decompose. As the peroxide bonds of the perfluoropolyether decompose, active free radicals containing terminal oxygen are released. Among them, the active free radicals with branched CF3 at the end undergo β-splitting to form a... A free radical without end-oxygen and trifluoroacetyl fluoride, an active free radical without end-branched CF3 releases oxygen free radicals. These free radicals complete deoxygenation through coupling. Finally, the gaseous material generated by deoxygenation is passed through the precooler (2) for preliminary cooling and then through gas-liquid phase separation. The liquid phase recovers part of the perfluoropolyether, and the remaining gas phase is condensed by the condenser (3) to obtain crude trifluoroacetyl fluoride. Then, the crude trifluoroacetyl fluoride is purified by the purification device to obtain trifluoroacetyl fluoride with a purity of 99%.

6. The method for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride according to claim 5, characterized in that... The peroxide value of perfluoropolyether is 1-5 g / 100g.

7. The method for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride according to claim 6, characterized in that... The perfluoropolyether is a Y-type perfluoropolyether prepared by photo-oxidative polymerization with a peroxide value of 2.8 mmol / kg or a Y-type perfluoropolyether prepared by photo-oxidative polymerization with a peroxide value of 1.62 mmol / kg. The structural formula of the peroxide of the Y-type perfluoropolyether is: CF3 [CF(CF3)CF2O]nCF(CF3)CF2OOCF2(CF3)CF[OCF2(CF3)CF]mCF3, where n and m are integers between 0 and 10.

8. The method for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride according to claim 5, characterized in that... The stirring speed of the deoxidizing reactor agitator is 100-400 rpm.

9. The method for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride according to claim 5, characterized in that... The cooling temperature of the precooler (2) is -10-10℃, and the condensing temperature of the condenser (3) is -70℃.

10. The method for removing peroxides from perfluoropolyethers and preparing trifluoroacetyl fluoride according to claim 5, characterized in that... The method of collection and purification is as follows: the crude trifluoroacetyl fluoride after condensation is introduced into the side of the distillation column (4) of the purification device. Then, the waste gas contained in the crude trifluoroacetyl fluoride is separated from the trifluoroacetyl fluoride by the packing (5) in the distillation column (4). Then, the trifluoroacetyl fluoride is cooled into liquid by the -35 refrigerant in the top of the distillation column (4). The cooled trifluoroacetyl fluoride is discharged from the top outlet (8) of the distillation column (4) into the high-pressure stainless steel collection bottle (6) and the weight is measured. The purity is analyzed by chromatography. Then, the perfluoropolyether gas in the high-pressure stainless steel collection bottle (6) is discharged into the storage tank (7) for storage. At the same time, the separated waste gas is introduced into the alkaline washing tank (10) through the side outlet (9) of the distillation column (4) and absorbed and discharged by the NaOH solution in the alkaline washing tank (10). The peroxide value of the discharged product is measured to be 0.08 mmol / kg by iodometric titration.

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