Method for preparing perfluoropolyether by microchannel reactor

Abstract

The invention discloses a method for preparing perfluoropolyether by a microchannel reactor. The method comprises the following specific steps: step 1, respectively adding molecular sieves into diethylene glycol dimethyl ether and tetramethylethylenediamine; 2, a reaction device is a micro-channel reactor, diethylene glycol dimethyl ether is adopted as a solvent, tetramethylethylenediamine is adopted as a catalyst, and the raw materials are introduced into the micro-channel reactor for a reaction; and step 3, adding the perfluoropolyether acyl fluoride prepared in the step 2 into a reaction device, then adding a catalyst antimony pentafluoride, carrying out mild stirring, and carrying out a reduced pressure reaction under the condition of not exceeding 0 DEG C to obtain the perfluoropolyether.

Description

Technical Field

[0001] The present application relates to the technical field of organic material synthesis, and in particular to a method for preparing perfluoropolyether using a microchannel reactor. Background Art

[0002] The space environment involves ultra-high vacuum, extreme temperature, strong radiation and weightlessness (microgravity), so the performance requirements for space lubricants are also relatively stringent. In addition to having general performance in the atmospheric environment, space lubricants also need to have lubrication properties that can adapt to the space environment. Perfluoropolyether has excellent thermal stability, extremely low evaporation, good viscosity-temperature characteristics, low surface tension and good radiation stability due to its unique chemical structure, and is widely used in the lubrication components of spacecraft. K-type perfluoropolyether has excellent thermal stability for 1400cm -1 ~4800cm -1 The band transmittance within the range is high; it can resist oxidation by atomic oxygen in low earth orbit and has good antioxidant properties; it has good anti-wear and friction reduction properties under vacuum and a small friction coefficient; the pour point is low, and the pour point of perfluoropolyether can reach below -60°C.

[0003] K-type perfluoropolyether is a series of branched homopolymers formed by anionic polymerization using perfluoropropylene oxide (HFPO) as a raw material and CsF as a catalyst in an aprotic solvent. It was first reported by Selman and Skehan and registered as a trademark by DuPont.

[0004] At present, the synthesis and production of K-type perfluoropolyether has been industrialized, but due to the complex preparation technology and expensive raw materials, the product price is very high, which greatly affects its application. In addition, the different polymerization degrees of perfluoropolyether will lead to different performances. Therefore, in order to obtain products with excellent performance, the controllable synthesis of K-type perfluoropolyether is a problem that needs to be solved urgently. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the purpose of the present application is to provide a method for preparing perfluoropolyether using a microchannel reactor, so as to solve the problems of complex perfluoropolyether preparation technology and high difficulty in controllable synthesis in the prior art.

[0006] In order to solve the above technical problems, this application adopts the following technical solutions:

[0007] A method for preparing perfluoropolyether in a microchannel reactor, the specific steps are as follows:

[0008] Step 1: adding molecular sieves to diethylene glycol dimethyl ether and tetramethylethylenediamine respectively;

[0009] Step 2: The reaction device is a microchannel reactor, diethylene glycol dimethyl ether is used as a solvent, and the catalyst is tetramethylethylenediamine. The catalyst and the solvent are stirred evenly to obtain a raw material solution, and the raw material solution is sent into the microchannel reactor through a peristaltic pump; hexafluoropropylene oxide is sent into the microchannel reactor through fluid transmission for reaction, and a layered solution is obtained after the reaction, and the lower clear liquid is perfluoropolyether acyl fluoride; wherein the molar ratio of diethylene glycol dimethyl ether to tetramethylethylenediamine is 1: (0.02-0.08); the temperature in the reactor is -60°C to -20°C, the gas flow rate of hexafluoropropylene oxide is 5-15mL / min, and the length of the microchannel in the microchannel reactor is 10-50m;

[0010] Step 3: Add the perfluoropolyether acyl fluoride prepared in step 2 into a reaction device, then add antimony pentafluoride as a catalyst, stir gently, and react under reduced pressure at a temperature not exceeding 0° C. to obtain perfluoropolyether.

[0011] Preferably, in step 1, the 4A molecular sieve is dried at 800° C. for 6 hours, and then the dried 4A molecular sieve is added to ethylene glycol dimethyl ether and tetramethylethylenediamine, respectively, and left for 24 hours; wherein 100 g of molecular sieve is added to every 500 mL of ethylene glycol dimethyl ether or tetramethylethylenediamine.

[0012] Preferably, in step 2, a T-type gas-liquid mixer is further provided, wherein the T-type gas-liquid mixer has an inlet end I, an inlet end II and an outlet end; wherein the inlet end of the peristaltic pump is used for inputting the raw material solution, and the outlet end of the peristaltic pump is fluidically connected to the inlet end I of the T-type gas-liquid mixer; hexafluoropropylene oxide is inputted from the inlet end II of the T-type gas-liquid mixer, and the hexafluoropropylene oxide enters the T-type gas-liquid mixer after passing through a gas mass flowmeter, and the gas mass flowmeter is used to detect the flow rate of hexafluoropropylene oxide; the outlet end of the T-type gas-liquid mixer is fluidically connected to the microchannel inlet end of the microchannel reactor, and the microchannel outlet end of the microchannel reactor is fluidically connected to the reaction device; after the raw material solution and hexafluoropropylene oxide are mixed in the T-type gas-liquid mixer, they enter the microchannel reactor through the outlet end of the T-type gas-liquid mixer for reaction.

[0013] Preferably, in step 3, the reaction temperature is -20°C to 0°C, the reaction is carried out under nitrogen protection, and the mass ratio of perfluoropolyether acyl fluoride to antimony pentafluoride is 1:(0.03 to 0.07).

[0014] Compared with the prior art, this application has the following beneficial effects:

[0015] 1. The present application adopts a microchannel reactor to prepare perfluoropolyether acyl fluoride, but the present application finds that the catalyst for preparing perfluoropolyether acyl fluoride in the prior art is insoluble in the solvent diethylene glycol dimethyl ether, which causes the traditional catalyst to easily clog the microchannel reactor, thereby affecting the reaction process; for this reason, the present application finds that the use of tetramethylethylenediamine as a catalyst can solve this problem well, and the use of a microchannel reactor makes the contact between the reactants more sufficient, and under the action of the catalyst, the reaction rate and conversion rate are improved; at the same time, the microchannel reactor has a small volume and a short reaction time, and can quickly reach a reaction equilibrium, reducing the generation of by-products.

[0016] 2. The present application also uses a T-type gas-liquid mixer to efficiently mix hexafluoropropylene oxide and the raw material solution, ensuring that the two are fully mixed before entering the microchannel reactor, which greatly improves the mass transfer efficiency, shortens the reaction time, and reduces the pressure fluctuation in the reactor; at the same time, with the use of a gas mass flow meter and a peristaltic pump, the flow rate of hexafluoropropylene oxide and the input amount of the raw material solution can be accurately controlled, ensuring the high consistency and repeatability of the reaction conditions. This not only improves the purity of the product, but also enhances the stability of the process.

[0017] 3. The present application uses molecular sieves to pretreat the raw materials to remove moisture therein, thereby ensuring the purity of the reaction system and reducing the generation of by-products, which not only improves the product quality but also reduces the difficulty and cost of subsequent purification steps; at the same time, by precisely controlling the flow rate of hexafluoropropylene oxide, the reaction temperature and the amount of catalyst, the generation of by-products can be minimized and the yield of the target product can be increased. The combination of low temperature and nitrogen protection further reduces the possibility of side reactions.

[0018] 4. The method described in this application significantly improves the synthesis efficiency, product purity and yield of perfluoropolyether by adopting a microchannel reactor and a series of optimization measures, while ensuring the safety and environmental protection of the reaction; the method described in this application is not only suitable for laboratory research, but also has the potential for industrial production, providing a new, efficient and reliable way for the preparation of perfluoropolyether. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a flow chart of a method for preparing perfluoropolyether using a microchannel reactor in the present application. DETAILED DESCRIPTION

[0020] This application will combine the embodiments of this application and the accompanying drawings to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on this application belong to the scope of protection of this application.

[0021] Unless otherwise indicated in specific cases in this application, the numerical ranges listed herein include the upper and lower limits, as well as all integers and fractions within the range, and are not limited to the specific values ​​listed when defining the range.

[0022] 1. A method for preparing perfluoropolyether using a microchannel reactor

[0023] Step 1: adding molecular sieves to diethylene glycol dimethyl ether and tetramethylethylenediamine respectively;

[0024] Step 2: The reaction device is a microchannel reactor, diethylene glycol dimethyl ether is used as a solvent, and the catalyst is tetramethylethylenediamine. The catalyst and the solvent are stirred evenly to obtain a raw material solution, and the raw material solution is fed by a peristaltic pump; hexafluoropropylene oxide is fed through a gas mass flow meter, and the solution and gas are mixed by a T-type gas-liquid mixer and enter the microchannel reactor, and the molar ratio of diethylene glycol dimethyl ether to tetramethylethylenediamine is 1: (0.02-0.08); the temperature in the reactor is -60°C to -20°C, the gas flow rate of hexafluoropropylene oxide is 5-15mL / min, and the length of the microchannel in the microchannel reactor is 10-50m; after the reaction, a layered solution is obtained, and the lower clarified liquid is perfluoropolyether acyl fluoride;

[0025] Step 3: Add the perfluoropolyether acyl fluoride prepared in step 2 into a reaction device, then add antimony pentafluoride as a catalyst, stir gently, and react under reduced pressure at a temperature not exceeding 0° C. to obtain perfluoropolyether.

[0026] The present application found in the study of the prior art that although the synthesis and production of perfluoropolyether has been industrialized, due to the complex preparation technology and expensive raw materials, the product price is very expensive, which greatly affects its application. In addition, the different polymerization degrees of perfluoropolyether will lead to different performances. Therefore, in order to obtain products with excellent performance, the controllable synthesis of perfluoropolyether is a problem that needs to be solved urgently. However, in traditional reactors, the mass transfer and heat transfer efficiency are low, resulting in problems such as slow reaction rate, many by-products, and uneven reaction. Especially when dealing with high viscosity or highly reactive substances, traditional stirred tank reactors are difficult to achieve rapid and uniform mixing, which further increases the difficulty of controllable synthesis of perfluoropolyether. For this reason, the present application considers the use of a microchannel reactor for preparation. The microchannel reactor has an extremely high specific surface area and efficient mass transfer and heat transfer characteristics, and can achieve uniform temperature distribution and sufficient material mixing in a short time, which not only improves the reaction rate, but also reduces the generation of by-products, and also has the prospect of industrial application. However, when the present application adopts a microchannel reactor for preparation, it is found that when the prior art generates perfluoropolyether acyl fluoride by polymerization of hexafluoropropylene oxide, the commonly used catalyst is cesium fluoride (CsF), rubidium fluoride (RbF), potassium fluoride (KF), sodium fluoride (NaF) and other alkali metal fluoride salts, which are insoluble solids in the solvent diethylene glycol dimethyl ether and are easy to block the microchannel. For this reason, the present application screened the catalyst, and it was found that the use of tetramethylethylenediamine solution as a catalyst can solve the problem of microchannel blockage while synthesizing perfluoropolyether acyl fluoride. Subsequently, the present application further studied the synthesis process and found that when perfluoropolyether acyl fluoride is prepared by a microchannel reactor, the polymerization degree of perfluoropolyether acyl fluoride is related to the time for the raw material to react in the microchannel reactor. When the reaction time is kept within a certain range, the longer the microchannel length in the microchannel reactor and the smaller the gas flow rate, the greater the polymerization degree of perfluoropolyether acyl fluoride. Compared with the product prepared in the present application, the product prepared in the prior art has a wider molecular weight distribution than the example, showing a Poisson distribution; while the product prepared in the present application has a narrower molecular weight distribution, showing a normal distribution, and a narrower degree of polymerization distribution than the comparative example. In other words, in the method described in the present application, by controlling the reaction time, microchannel length and gas flow rate, the degree of polymerization of perfluoropolyether acyl fluoride can be controlled, and finally the controllable synthesis of perfluoropolyether can be achieved.

[0027] In some embodiments of the present application, in step 2, the molar ratio of diethylene glycol dimethyl ether to tetramethylethylenediamine is 1: (0.02-0.08), and tetramethylethylenediamine can be well dissolved in diethylene glycol dimethyl ether, so that the catalyst will not block the microchannel during the reaction; and, the amount of the catalyst is controlled, and this low amount of catalyst can ensure the smooth progress of the reaction without introducing too many impurities, thereby reducing the generation of by-products. Therefore, the molar ratio of diethylene glycol dimethyl ether to tetramethylethylenediamine can be 1: 0.02, 1: 0.03, 1: 0.04, 1: 0.05, 1: 0.06, 1: 0.07, 1: 0.08, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0028] In some embodiments of the present application, in step 2, the temperature in the reactor can be -60°C, -50°C, -40°C, -30°C, -20°C, etc., and all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0029] In some embodiments of the present application, in step 2, the gas flow rate of hexafluoropropylene oxide is 5-15mL / min, and the gas flow rate is too low to obtain the target product, but the gas flow rate is too high to cause excessive polymerization, making the degree of polymerization of the target product difficult to control. Therefore, the gas flow rate of hexafluoropropylene oxide can be 5mL / min, 6mL / min, 7mL / min, 8mL / min, 9mL / min, 10mL / min, 11mL / min, 12mL / min, 13mL / min, 14mL / min, 15mL / min, etc., and all ranges and sub-ranges between the above values. It should be understood that, in embodiments, any of the above ranges can be combined with any other ranges.

[0030] In some embodiments of the present application, in step 2, by adjusting the length of the microchannel in the microchannel reactor, the control of the polymerization degree of the target product can be achieved. If the length is too short, the reaction process will be too short and sufficient target products cannot be formed; but if the length is too long, the polymerization reaction time will be too long, resulting in a large number of by-products. Therefore, the length of the microchannel in the microchannel reactor can be 10m, 15m, 20m, 25m, 30m, 35m, 40m, 45m, 50m, etc., as well as all ranges and sub-ranges between the above values. It should be understood that in embodiments, any of the above ranges can be combined with any other ranges.

[0031] In some embodiments of the present application, in step 1, 4A molecular sieve is dried at 800°C for 6h, and then the dried 4A molecular sieve is added to ethylene glycol dimethyl ether and tetramethylethylenediamine respectively, and placed for 24h; wherein, 100g molecular sieve is added to every 500mL ethylene glycol dimethyl ether or tetramethylethylenediamine. The present application finds that if there is residual moisture in the raw material, the active anion intermediate formed during the polymerization process will be inactivated, affecting the chain growth, thereby affecting the control of the degree of polymerization of the target product. For this reason, the present application uses 4A molecular sieve to dry and dehydrate the solvent and catalyst, so that hexafluoropropylene oxide is effectively polymerized to obtain a higher yield.

[0032] In some embodiments of the present application, in step 2, a T-type gas-liquid mixer is also provided, wherein the T-type gas-liquid mixer has an inlet end I, an inlet end II and an outlet end; wherein the inlet end of the peristaltic pump is used for the input of the raw material solution, and the outlet end of the peristaltic pump is connected to the inlet end I fluid of the T-type gas-liquid mixer; hexafluoropropylene oxide is input from the inlet end II of the T-type gas-liquid mixer, and hexafluoropropylene oxide enters the T-type gas-liquid mixer after passing through a gas mass flow meter, and the gas mass flow meter is used to detect the flow rate of hexafluoropropylene oxide; the outlet end of the T-type gas-liquid mixer is connected to the microchannel inlet end fluid of the microchannel reactor, and the microchannel outlet end of the microchannel reactor is connected to the reaction device fluid; after the raw material solution and hexafluoropropylene oxide are mixed in the T-type gas-liquid mixer, they enter the microchannel reactor through the outlet end of the T-type gas-liquid mixer for reaction. The hexafluoropropylene oxide and the raw material solution are pre-mixed by the T-type gas-liquid mixer before entering the microchannel reactor, ensuring the rapid and uniform contact of the two in the microchannel, and further improving the mass transfer efficiency.

[0033] In some embodiments of the present application, in step 3, the reaction temperature is -20°C to 0°C, the reaction is carried out under nitrogen protection, and the mass ratio of perfluoropolyether acyl fluoride to antimony pentafluoride is 1:(0.03-0.07). The reaction temperature can be -20°C, -15°C, -10°C, -5°C, 0°C, etc., and all ranges and sub-ranges between the above values; the mass ratio of perfluoropolyether acyl fluoride to antimony pentafluoride can be 1:0.03, 1:0.04, 1:0.05, 1:0.06, 1:0.07, etc., and all ranges and sub-ranges between the above values; it should be understood that in the embodiment, any of the above ranges can be combined with any other ranges.

[0034] 2. Examples and Comparative Examples

[0035] Example 1

[0036] Step 1: Dry the 4A molecular sieve at 800°C for 6 hours, then add the dried 4A molecular sieve to ethylene glycol dimethyl ether and tetramethylethylenediamine respectively and leave for 24 hours; wherein, 100g of molecular sieve is added to every 500mL of ethylene glycol dimethyl ether or tetramethylethylenediamine.

[0037] Step 2: Add diethylene glycol dimethyl ether (2.05 mL, 13.65 mmol) to tetramethylethylenediamine (40 mL, 0.273 mmol), stir evenly in a round-bottom flask, feed through a peristaltic pump, feed hexafluoropropylene oxide gas through a gas mass flow meter, and the liquid and gas enter the microchannel reactor after passing through a T-type gas-liquid mixer and react at a low temperature of -60°C.

[0038] Step 3: At -20°C, under nitrogen protection, add 20g of perfluoropolyether acyl fluoride dropwise to 10g of antimony pentafluoride, and continue the reaction until no gas is generated in the reaction system. Slowly add water at low temperature to quench, separate the lower layer of liquid and calculate the molecular weight.

[0039] On the basis of Example 1, experiments were conducted using microchannel reactors with microchannels of different lengths and different gas flow rates. The other steps were exactly the same as those in Example 1. For details, see Tables 1 to 4.

[0040] When the length of the microchannel is 10m:

[0041] Table 1

[0042]

[0043] When the length of the microchannel is 15m:

[0044] Table 2

[0045] Gas flow rate (mL / min) 5 10 15 Product mass (g) 2.16g 8.67g 12.26g Average molecular weight of product 454.18 451.14 435.51

[0046] When the microchannel length is 25m:

[0047] Table 3

[0048] Gas flow rate (mL / min) 5 10 15 Product mass (g) 3.90g 9.81g 13.31g Average molecular weight of product 458.21 443.41 440.82

[0049] When the microchannel length is 40m:

[0050] Table 4

[0051] Gas flow rate (mL / min) 5 10 15 Product mass (g) 8.05g 9.21g 15.07g Average molecular weight of product 469.47 461.96 453.55

[0052] When the microchannel length is 50m:

[0053] Table 5

[0054] Gas flow rate (mL / min) 5 10 15 Product mass (g) 10.19g 15.26g 18.84g Average molecular weight of product 476.79 464.71 456.45

[0055] Comparative Example 1

[0056] Improvements were made based on Example 1, except that: CsF was used to replace tetramethylethylenediamine of equal mass as the catalyst in Comparative Example 1. In Comparative Example 1, since the CsF catalyst was insoluble in the solvent, the microchannel in the microchannel reactor was clogged during the synthesis process.

[0057] The above examples demonstrate the effects of microchannel length and gas flow rate on product quality and average molecular weight during the synthesis of perfluoropolyether (PFPE). By comparing the experimental results under different conditions, it can be seen that:

[0058] (1) Effect of microchannel length on reaction efficiency and product quality

[0059] As the length of the microchannel increases, the product quality generally shows an upward trend. When the microchannel length increases from 10m to 50m, the product quality increases significantly under the same gas flow conditions. This shows that longer microchannels provide more reaction time and space, which is conducive to improving reaction conversion rate and yield.

[0060] As the length of the microchannel increases, the average molecular weight of the product also shows a trend of gradually increasing. The longer microchannel allows the reactants to have more time to undergo polymerization, thereby forming perfluoropolyether acyl fluoride with a higher molecular weight. This shows that the present application can obtain perfluoropolyether acyl fluoride with different molecular weights by controlling the length of the microchannel, and ultimately achieve the purpose of controllable synthesis.

[0061] (2) Effect of gas flow rate on reaction efficiency and product quality

[0062] Under the same microchannel length, as the gas flow rate increases, the product quality first increases and then tends to stabilize or slightly decreases. This is because although a higher gas flow rate increases the input amount of reactants, too high a flow rate may lead to incomplete reaction and affect the conversion rate.

[0063] As the gas flow rate increases, the average molecular weight of the product generally shows a downward trend. A higher gas flow rate may lead to a shorter reaction time, thereby reducing the degree of polymerization and lowering the molecular weight of the product.

[0064] (3) Optimize reaction conditions

[0065] It can be seen from the above examples that the 50m microchannel shows the highest product quality and larger average molecular weight under all gas flow conditions, indicating that longer microchannels help improve reaction efficiency and product quality. For different microchannel lengths, a gas flow rate of 10mL / min can usually provide a better balance, which can ensure higher product quality and maintain a relatively high average molecular weight. Too low or too high a gas flow rate may lead to a decrease in yield or molecular weight.

[0066] In summary, by extending the length of the microchannel, the yield of perfluoropolyether is significantly improved, especially in longer microchannels, the product quality is significantly increased. Longer microchannels and moderate gas flow rates help to form higher molecular weight perfluoropolyether acyl fluoride, which is very important for certain applications (such as lubricants, sealing materials, etc.). At the same time, by adjusting the length of the microchannel and the gas flow rate, the reaction conversion rate and the molecular weight of the product can be flexibly controlled, achieving fine control of product quality. The efficient mass transfer and heat transfer characteristics of the microchannel reactor and the precise feed control system ensure the high consistency and repeatability of the reaction conditions, which are suitable for industrial production.

[0067] The method described in this application is not only suitable for laboratory-scale research, but also has good industrial amplification potential. By optimizing the microchannel length and gas flow rate, large-scale production can be achieved while maintaining high quality. The small size and high efficiency of the microchannel reactor reduce the use of chemicals, reduce the generation of waste, and have good environmental and economic benefits. This application significantly improves the synthesis efficiency, yield and product quality of perfluoropolyether by optimizing the structural parameters (such as microchannel length) and operating conditions (such as gas flow rate) of the microchannel reactor, demonstrating excellent technical effects and application prospects.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present application rather than to limit the technical solution. Ordinary technicians in this field should understand that those modifications or equivalent substitutions of the technical solution of the present application that do not depart from the purpose and scope of the technical solution of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for preparing perfluoropolyether using a microchannel reactor, characterized in that: The specific steps are as follows: Step 1: adding molecular sieves to diethylene glycol dimethyl ether and tetramethylethylenediamine respectively; Step 2: The reaction device is a microchannel reactor, diethylene glycol dimethyl ether is used as a solvent, and the catalyst is tetramethylethylenediamine. The catalyst and the solvent are stirred evenly to obtain a raw material solution, and the raw material solution is sent into the microchannel reactor through a peristaltic pump; hexafluoropropylene oxide is sent into the microchannel reactor through fluid transmission for reaction, and a layered solution is obtained after the reaction, and the lower clear liquid is perfluoropolyether acyl fluoride; wherein the molar ratio of diethylene glycol dimethyl ether to tetramethylethylenediamine is 1: (0.02-0.08); the temperature in the reactor is -60°C to -20°C, the gas flow rate of hexafluoropropylene oxide is 5-15mL / min, and the length of the microchannel in the microchannel reactor is 10-50m; Step 3: Add the perfluoropolyether acyl fluoride prepared in step 2 into a reaction device, then add antimony pentafluoride as a catalyst, stir gently, and react under reduced pressure at a temperature not exceeding 0° C. to obtain perfluoropolyether.

2. The method according to claim 1, characterized in that: In step 1, the 4A molecular sieve is dried at 800° C. for 6 hours, and then the dried 4A molecular sieve is added to ethylene glycol dimethyl ether and tetramethylethylenediamine, respectively, and left for 24 hours; wherein 100 g of molecular sieve is added to every 500 mL of ethylene glycol dimethyl ether or tetramethylethylenediamine.

3. The method according to claim 1, characterized in that: In step 2, a T-type gas-liquid mixer is further provided, wherein the T-type gas-liquid mixer has an inlet end I, an inlet end II and an outlet end; wherein the inlet end of the peristaltic pump is used for inputting the raw material solution, and the outlet end of the peristaltic pump is fluidically connected to the inlet end I of the T-type gas-liquid mixer; hexafluoropropylene oxide is inputted from the inlet end II of the T-type gas-liquid mixer, and the hexafluoropropylene oxide enters the T-type gas-liquid mixer after passing through a gas mass flowmeter, and the gas mass flowmeter is used to detect the flow rate of the hexafluoropropylene oxide; the outlet end of the T-type gas-liquid mixer is fluidically connected to the microchannel inlet end of the microchannel reactor, and the microchannel outlet end of the microchannel reactor is fluidically connected to the reaction device; after the raw material solution and hexafluoropropylene oxide are mixed in the T-type gas-liquid mixer, they enter the microchannel reactor through the outlet end of the T-type gas-liquid mixer for reaction.

4. The method according to claim 1, characterized in that: In step 3, the reaction temperature is -20°C to 0°C, the reaction is carried out under nitrogen protection, and the mass ratio of perfluoropolyether acyl fluoride to antimony pentafluoride is 1:(0.03 to 0.07).

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