Industrial control method and system for efficient synthesis of perfluoropolyether acyl fluoride

Abstract

The application discloses an industrial control method and system for efficiently synthesizing perfluoropolyether acyl fluoride. The method uses hexafluoropropylene and oxygen as raw materials and introduces fluorine fluid for reaction in a photocatalytic oxidation reactor. The photocatalytic oxidation reactor is provided with a UV lamp, a stirrer and a gas distributor. The upper part of the photocatalytic oxidation reactor is provided with a liquid feed inlet, a gas phase outlet and a reflux port. The lower part of the photocatalytic oxidation reactor is provided with a gas feed inlet and a discharge port. The gas feed inlet is provided with a gas distributor, which is located at the bottom of the photocatalytic oxidation reactor. By controlling various process control parameters of the photocatalytic oxidation reactor during the reaction, the efficient synthesis of perfluoropolyether acyl fluoride can be realized, the proportion of the required molecular weight control range can be improved, the product molecular weight level can be improved, and the method has the advantages of low equipment cost, easy production control, high safety, easy scale production and the like.

Description

Technical Field

[0001] This invention belongs to the field of fluorochemical technology, specifically, it is an industrial control method and system for the efficient synthesis of perfluoropolyether fluoride. Background Technology

[0002] Perfluoropolyether (PFPE) is a high molecular weight polymer that is an oily liquid at room temperature. Due to its unique thermal stability, oxidative stability, high insulation strength, and low toxicity, it is an ideal test solution for electronic reliability testing and is used as a thermal shock oil for hermeticity testing and thermal shock testing in the semiconductor and electronic packaging fields. In industrial production, perfluoroolefins and oxygen are typically used as raw materials. After polymerization with chemical initiators or ultraviolet light to obtain perfluoropolyether acyl fluoride, it is then subjected to fluorination treatment to obtain stable perfluoropolyether. Therefore, perfluoropolyether acyl fluoride is the precursor to obtain perfluoropolyether and is also the key factor determining the conversion rate of perfluoropolyether.

[0003] The invention patent with publication number CN106866953A discloses a method for manufacturing perfluoropolyoxyolefin peroxide compounds. This method uses a microreactor to react perfluoroolefins and oxygen in the microreactor while simultaneously irradiating the mixture in the microreactor with light. This allows for the continuous production of perfluoropolyoxyolefin peroxide compounds. However, the yield of perfluoropolyoxyolefin peroxide compounds synthesized by this method is less than 40%. Even though this method introduces a fluorine source into the mixture of perfluoroolefins and oxygen to increase the reaction rate between perfluoroolefins and oxygen and to make the PO value (molecular weight of active oxygen / molecular weight of the polymer) of the perfluoropolyoxyolefin peroxide compounds smaller, the yield of the perfluoropolyoxyolefin peroxide compounds is not improved.

[0004] In addition, invention patent CN114276532A discloses a method and apparatus for preparing perfluoropolyether peroxide. This method involves pre-cooling fluoroalkane and mixing it with perfluoroolefin to obtain a premixed liquid, then mixing it with oxygen as a reaction liquid and introducing it into a reactor for oxidative polymerization. Finally, the fluoroalkane is separated and recovered to obtain the perfluoropolyether peroxide. The yield of perfluoropolyether peroxide prepared using this method can reach up to 71%. Invention patent CN112940237A discloses a method for preparing perfluoropolyolefin peroxide and perfluoropolyether, which has… The first method involves using a high-gravity reactor to react a perfluorinated system with oxygen to produce perfluoropolyoxyethylene peroxide, achieving a yield of up to 64.2%. Patent CN114621427A discloses a process for preparing perfluoropolyethers with peroxy peroxide via photo-oxidative polymerization. This process uses a photopolymerization reactor equipped with an ultraviolet generator, stirrer, and gas distributor. Fluorinated olefins and oxygen undergo oxidative polymerization within the reactor to obtain perfluoropolyether products containing peroxy peroxide, achieving a yield of up to 71.5%. Therefore, the yields of perfluoropolyethers with peroxy peroxide described in these patents do not exceed 72% (based on perfluoroolefins). For the industrial-scale production of perfluoropolyethers, the synthesis yield still needs improvement. It is evident that in the production of perfluoropolyethers, the aforementioned patents result in low utilization of fluoroolefins and low product yield, only around 70%, due to factors such as gas-liquid heterogeneous reaction mass transfer efficiency and process control conditions.

[0005] In the prior art, invention patent CN111138651A discloses a method for synthesizing perfluoropolyether peroxide. This method involves continuously feeding fluorinated olefins, oxygen, and a solvent (fluorocyclic ether, hydrofluoroether, hexafluoropropylene dimer, hexafluoropropylene trimer, or perfluoroalkanes) into a microreactor for mixing and dissolution. The resulting reaction solution is then continuously fed into a photoinitiated reactor. Under ultraviolet light initiation, the fluorinated olefins and oxygen react in the solvent. The reaction product is then evaporated, and the solvent is recovered to obtain the perfluoropolyether peroxide product. Its molecular weight can be controlled between 1000 and 10000, with a yield reaching up to 90%. However, the microchannel reactor used in this patent method is expensive. Furthermore, due to the internal structure of the microchannel reactor, olefins and oxygen easily generate products with high peroxide content within the microchannels, posing certain safety hazards. It can also be blocked by solid particles and impurities, leading to discontinuous production processes, increasing the difficulty of equipment detection and process control, and raising operating costs. Summary of the Invention

[0006] The purpose of this invention is to provide an industrial control method for the efficient synthesis of perfluoropolyether fluoride. Using hexafluoropropylene and oxygen as raw materials, a fluorine fluid is introduced into a photocatalytic oxidation reactor for reaction. By controlling various process control parameters of the photocatalytic oxidation reactor during the reaction, not only can the high-efficiency synthesis of perfluoropolyether fluoride be achieved, but the proportion of the required molecular weight control range can also be increased, thereby improving the molecular weight level of the product. This method has the advantages of low equipment cost, easy production control, high safety, and ease of large-scale production.

[0007] This invention is achieved through the following technical solution: an efficient industrial control method for synthesizing perfluoropolyether fluoride, using hexafluoropropylene and oxygen as raw materials, reacting them in a photocatalytic oxidation reactor to produce perfluoropolyether fluoride. The photocatalytic oxidation reactor is equipped with an ultraviolet lamp, a stirrer, and a gas distributor. The upper part of the photocatalytic oxidation reactor has a liquid inlet, a gas outlet, and a reflux outlet, while the lower part has a gas inlet and a discharge outlet. A gas distributor is installed above the gas inlet and is located at the bottom of the photocatalytic oxidation reactor.

[0008] Hexafluoropropylene from the hexafluoropropylene storage tank and fluorine fluid from the fluorine fluid storage tank are fed into the photocatalytic oxidation reactor via material pumps through the liquid inlet. Oxygen from the oxygen storage tank and nitrogen from the nitrogen storage tank are metered by gas flow meters and fed into the photocatalytic oxidation reactor through the gas inlet and gas distributor, respectively. Unreacted hexafluoropropylene is sent to the condenser through the gas phase outlet to be condensed into liquid phase, and then returned to the photocatalytic oxidation reactor through the reflux port.

[0009] The reaction process should include at least the following control methods:

[0010] (I) Control the opening time of the hexafluoropropylene feed valve between the hexafluoropropylene storage tank and the material pump so that hexafluoropropylene is fed into the photocatalytic oxidation reactor in one go through the material pump;

[0011] (II) Control the opening time of the fluorine fluid feed valve between the fluorine fluid storage tank and the material pump and the pump speed of the material pump so that the fluorine fluid is intermittently fed into the photocatalytic oxidation reactor.

[0012] (III) Control the opening time and oxygen flow rate of the oxygen inlet valve between the oxygen storage tank and the gas flow meter to ensure continuous feeding into the photocatalytic oxidation reactor;

[0013] (IV) Control the opening time of the nitrogen vent valve between the nitrogen storage tank and the gas flow meter;

[0014] (V) Control the wattage of the ultraviolet lamp, the speed of the stirrer, the pressure of the pressure gauge, the temperature detected by the temperature probe, and the reaction time on the photocatalytic oxidation reactor;

[0015] (VI) Control the opening time and valve position of the reflux regulating valve between the reflux port and the condenser.

[0016] The amount of hexafluoropropylene fed is controlled between 50 and 800 kg.

[0017] In the photocatalytic oxidation reactor, fluorine fluid is added for the first time after hexafluoropropylene is fed and before oxygen is introduced. Then, during the reaction process, fluorine fluid is added every 3 to 10 hours. When adding fluorine fluid, the pumping speed of the material pump is controlled at 5 to 30 Hz, and the total amount of fluorine fluid added is controlled at 5 to 50 kg.

[0018] The fluorine fluid is a perfluoropolyether.

[0019] The nitrogen gas is purged into the photocatalytic oxidation reactor before feeding, and nitrogen protection is activated for the photocatalytic oxidation reactor after the reaction is completed and the material is discharged.

[0020] The agitator includes at least two agitators of different heights, and the agitators employ differential agitation with the agitator speed controlled between 5 and 50 Hz.

[0021] The wattage of the ultraviolet lamp is controlled between 8000W and 15000W, the pressure of the pressure gauge is controlled between 0 and 0.5MPa, the temperature detected by the temperature probe is controlled between -32 and -28℃, and the reaction time is controlled between 1 and 15h.

[0022] The temperature detected by the temperature probe on the condenser is controlled between -60 and -50°C.

[0023] The opening time and valve position of the reflux regulating valve are controlled according to the liquid level of the condenser.

[0024] An efficient industrial control system for the synthesis of perfluoropolyether fluoride includes a photocatalytic oxidation reactor, a hexafluoropropylene storage tank, a fluorine fluid storage tank, an oxygen storage tank, a nitrogen storage tank, a material pump, a gas flow meter, and a condenser.

[0025] The photocatalytic oxidation reactor is equipped with an ultraviolet lamp, a stirrer, and a gas distributor. The upper part of the photocatalytic oxidation reactor is equipped with a liquid inlet, a gas phase outlet, and a reflux outlet, while the lower part of the photocatalytic oxidation reactor is equipped with a gas inlet and a discharge outlet. The gas inlet is connected to the gas distributor and is located at the bottom of the photocatalytic oxidation reactor.

[0026] The hexafluoropropylene storage tank is connected to the liquid inlet of the photocatalytic oxidation reactor via a material pump, and a hexafluoropropylene feed valve is installed on the pipeline between the hexafluoropropylene storage tank and the material pump.

[0027] The fluorine fluid storage tank is connected to the liquid inlet of the photocatalytic oxidation reactor via a material pump, and a fluorine fluid inlet valve is installed on the pipeline between the fluorine fluid storage tank and the material pump.

[0028] The oxygen storage tank is connected to the gas inlet of the photocatalytic oxidation reactor via a gas flow meter, and an oxygen vent valve is installed on the pipeline between the oxygen storage tank and the gas flow meter.

[0029] The nitrogen storage tank is connected to the gas inlet of the photocatalytic oxidation reactor via a gas flow meter, and a nitrogen vent valve is installed on the pipeline between the nitrogen storage tank and the gas flow meter.

[0030] The condenser is connected to the gas phase outlet and reflux port of the photocatalytic oxidation reactor, and a reflux regulating valve is installed on the pipeline between the condenser and the reflux port.

[0031] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0032] (1) This invention is a process for preparing perfluoropolyether acyl fluoride by photocatalytic oxidation using hexafluoropropylene and oxygen as raw materials and intermittent batch reaction. By introducing perfluoropolyether multiple times during the preparation process, the high saturated oxygen content of perfluoropolyether can be utilized to increase the oxygen solubility in the reaction system, improve the mass transfer effect of the gas-liquid heterogeneous reaction, and achieve high-efficiency synthesis of perfluoropolyether acyl fluoride.

[0033] (2) By introducing perfluoropolyether into the preparation process, this invention can give full play to the advantages of perfluoropolyether as a solvent, such as low viscosity, good light transmittance, good chemical stability, non-toxicity and non-corrosiveness. Using perfluoropolyether as a solvent, there is no need to separate the product and the solvent (the final product is the same type of product), which can achieve the technical effect of reducing the total energy consumption of the process and is conducive to the smooth progress of the reaction.

[0034] (3) By reasonably controlling the process control parameters in the photocatalytic oxidation reaction and the amount of perfluoropolyether introduced each time in the preparation process, the method of the present invention can not only meet the requirements of efficient synthesis, but also stably improve the molecular weight of the perfluoropolyether acyl fluoride product, and has a higher selectivity for the control range of molecular weight.

[0035] (4) The method of the present invention can improve the single-pass conversion rate of monomers, satisfy the requirement that the single-pass conversion percentage of hexafluoropropylene is above 66%, and the single-pass yield of hexafluoropropylene reaches above 91%.

[0036] (5) The method of the present invention can achieve a molecular weight range of 500 to 15000 for perfluorinated polyether fluoride, and an active oxygen content of 0.1 to 0.5%.

[0037] (6) The method of the present invention uses a photocatalytic oxidation reactor with a specific structure to prepare perfluoropolyether fluoride by intermittent batch reaction. The photocatalytic oxidation reactor has a gas distributor and a stirrer. The stirrer uses two stirring paddles with different heights to achieve differential stirring, which can further improve the mass transfer effect and make the reaction process easy to control, suitable for industrial-scale production.

[0038] In summary, this invention introduces perfluoropolyether into the process of preparing perfluoropolyether acyl fluoride in a batch reactor for the first time. By combining a dedicated photocatalytic oxidation reactor and suitable process control conditions, it can achieve synthesis efficiency and molecular weight distribution comparable to microchannel reactors, reduce active oxygen content to 0.1%, and has advantages such as low production equipment cost, good reaction adaptability, easy industrial automation control, and suitability for large-scale production. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the industrial control system of the present invention.

[0040] Figure 2 This is a logic block diagram of the industrial control method of the present invention.

[0041] Figure 3 This is a schematic diagram of a conventional photocatalytic oxidation reactor.

[0042] Among them, 1—photocatalytic oxidation reactor, 2—ultraviolet lamp, 3—stirrer, 4—gas distributor, 5—liquid inlet, 6—gas phase outlet, 7—reflux port, 8—gas inlet, 9—discharge port, 10—fluorine fluid storage tank, 11—hexafluoropropylene storage tank, 12—material pump, 13—oxygen storage tank, 14—nitrogen storage tank, 15—gas flow meter, 16—condenser, 17—reflux regulating valve, 18—fluorine fluid inlet valve, 19—hexafluoropropylene inlet valve, 20—oxygen vent valve, 21—nitrogen vent valve, 22—product receiving tank, 23—tail gas absorption tower. Detailed Implementation

[0043] The invention's objective, technical solution, and beneficial effects will be further explained in detail below.

[0044] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the claimed invention. Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] This invention relates to an efficient industrial control method and system for synthesizing perfluoropolyether acyl fluoride. Specifically, it describes a production process for preparing perfluoropolyether acyl fluoride using a batch reactor. During the preparation process, a photocatalytic oxidation reactor 1 with a specific structure is employed, and a fluorine fluid (perfluoropolyether) is selectively introduced into the reactor 1. Combined with appropriate production process control conditions, under specific control methods, highly efficient mass transfer of the gas-liquid heterogeneous reaction in the photocatalytic oxidation reactor 1 can be achieved. This method efficiently synthesizes perfluoropolyether acyl fluoride products and has advantages such as improved monomer conversion efficiency, improved product quality, reduced process costs, simplified process control, guaranteed reaction stability and controllability, reaction safety, good adaptability, and ease of engineering scale-up.

[0046] Existing patents, such as CN111138651A, disclose that perfluorocyclic ethers, hydrofluoroethers, hexafluoropropylene dimers, and hexafluoropropylene trimers can be continuously added to a microchannel reactor as solvents along with perfluoroolefins and oxygen for reaction. While this can improve the solubility of reaction products and eliminate or reduce mass transfer barriers in gas-liquid heterogeneous reactions to some extent, the use of microchannel reactors presents several problems, primarily high process costs and difficulties in production control, which are not conducive to improving economic benefits after industrialization. Therefore, for the industrial production of perfluoropolyether acyl fluoride, it is imperative to find a production method with high synthesis efficiency, low process costs, and ease of industrial operation, namely the industrial control method and system described in this invention.

[0047] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0048] Example 1: Industrial Control System for High-Efficiency Synthesis of Perfluoropolyether Acrylamide

[0049] The industrial control system of this embodiment is applicable to the production process of preparing perfluoropolyether fluoride by reacting hexafluoropropylene and oxygen in photocatalytic oxidation reactor 1. Its structure is described in [reference needed]. Figure 1 As shown, it mainly consists of a photocatalytic oxidation reactor 1, a hexafluoropropylene storage tank 11, a fluorine fluid storage tank 10, an oxygen storage tank 13, a nitrogen storage tank 14, a material pump 12, a gas flow meter 15, and a condenser 16.

[0050] The photocatalytic oxidation reactor 1 is equipped with an ultraviolet lamp 2, a stirrer 3, and a gas distributor 4. The stirrer 3 is a twin-shaft stirrer with different heights of the impellers, employing differential stirring. The upper part of the photocatalytic oxidation reactor 1 has a liquid inlet 5, a gas outlet 6, and a reflux outlet 7. The lower part of the photocatalytic oxidation reactor 1 has a gas inlet 8 and a discharge outlet 9. The gas inlet 8 is connected to the gas distributor 4 and is located at the bottom of the photocatalytic oxidation reactor 1. A hexafluoropropylene storage tank 11 is connected to the liquid inlet 5 of the photocatalytic oxidation reactor 1 via a material pump 12, and a hexafluoropropylene inlet valve 19 is installed on the pipeline between the hexafluoropropylene storage tank 11 and the material pump 12. A fluorine fluid storage tank 10 is connected to the liquid inlet 5 of the photocatalytic oxidation reactor 1 via a material pump 12, and a fluorine fluid inlet valve 18 is installed on the pipeline between the fluorine fluid storage tank 10 and the material pump 12. Oxygen storage tank 13 is connected to the gas inlet 8 of photocatalytic oxidation reactor 1 via gas flow meter 15, and an oxygen vent valve 20 is installed on the pipeline between oxygen storage tank 13 and gas flow meter 15. Nitrogen storage tank 14 is connected to the gas inlet 8 of photocatalytic oxidation reactor 1 via gas flow meter 15, and a nitrogen vent valve 21 is installed on the pipeline between nitrogen storage tank 14 and gas flow meter 15. Condenser 16 is connected to the gas phase outlet 6 and reflux outlet 7 of photocatalytic oxidation reactor 1, and a reflux regulating valve 17 is installed on the pipeline between condenser 16 and reflux outlet 7. The reflux regulating valve 17 keeps the liquid level in condenser 16 constant, and controls part of the condensed hexafluoropropylene to return to photocatalytic oxidation reactor 1 via reflux outlet 7 to continue participating in the reaction. Part of the uncondensed gas phase tail gas is sent to tail gas absorption tower 23 for treatment.

[0051] During production, hexafluoropropylene from hexafluoropropylene storage tank 11 and fluorine fluid from fluorine fluid storage tank 10 are fed into photocatalytic oxidation reactor 1 via material pump 12 through liquid inlet 5. Oxygen from oxygen storage tank 13 and nitrogen from nitrogen storage tank 14 are metered by gas flow meter 15 and fed into photocatalytic oxidation reactor 1 via gas inlet 8 and gas distributor 4. Unreacted hexafluoropropylene is sent to condenser 16 through gas phase outlet 6 to be condensed into liquid phase and then returned to photocatalytic oxidation reactor 1 through reflux port 7. During the reaction process, the following controls are implemented based on the above system structure:

[0052] (I) Control the opening time of the hexafluoropropylene feed valve 19 between the hexafluoropropylene storage tank 11 and the material pump 12 so that hexafluoropropylene is fed into the photocatalytic oxidation reactor 1 in one go through the material pump 12;

[0053] (II) Control the opening time of the fluorine fluid inlet valve 18 between the fluorine fluid storage tank 10 and the material pump 12 and the pumping speed of the material pump 12 so that the fluorine fluid is intermittently fed into the photocatalytic oxidation reactor 1.

[0054] (III) Control the opening time and oxygen flow rate of the oxygen inlet valve 20 between the oxygen storage tank 13 and the gas flow meter 15 so that the oxygen is continuously fed into the photocatalytic oxidation reactor 1.

[0055] (IV) Control the opening time of the nitrogen gas inlet valve 21 between the nitrogen storage tank 14 and the gas flow meter 15;

[0056] (V) Control the wattage of the ultraviolet lamp, the speed of the stirrer, the pressure of the pressure gauge, the temperature detected by the temperature probe, and the reaction time on the photocatalytic oxidation reactor 1;

[0057] (VI) Control the opening time and valve position of the reflux regulating valve 17 between the reflux port 7 and the condenser 16.

[0058] Example 2: An industrial control method for the efficient synthesis of perfluoropolyether fluoride

[0059] This embodiment describes a process control method using remote computer control; its control flow is described in [reference needed]. Figure 2 As shown:

[0060] First, nitrogen purging valve 21 is opened to purge photocatalytic oxidation reactor 1 with nitrogen before feeding. After purging, hexafluoropropylene feed valve 19 and material pump 12 are opened, and material pump 12 is used to force hexafluoropropylene raw material from hexafluoropropylene storage tank 11 into photocatalytic oxidation reactor 1 in one go. After feeding is completed, hexafluoropropylene feed valve 19 is closed. Then, fluorine fluid feed valve 18 is opened, and material pump 12 is used to force fluorine fluid from fluorine fluid storage tank 10 into photocatalytic oxidation reactor 1. Then, the heater of photocatalytic oxidation reactor 1 is started, and the pressure on the pressure gauge of photocatalytic oxidation reactor 1 is controlled at 0.25 MPa, and the temperature detected by the temperature probe is controlled at -30℃. The differential speed stirrer is turned on, and the settings are adjusted accordingly. After the stirring frequency is set to 20Hz (upper) and 15Hz (lower) to ensure uniform dispersion of the material inside the reactor, the valve of the oxygen storage tank 13 is opened, the oxygen flow rate is controlled by the gas flow meter 15, and the ultraviolet lamp 2 (10000W) is turned on for irradiation. After reacting for 15 hours, the gas supply is stopped, and the discharge valve of the discharge port 9 is opened. The unreacted hexafluoropropylene condensate is vaporized after heating. The residual liquid phase of the vaporized product is sent to the product receiving tank 22. The product in the product receiving tank 22 is perfluoropolyether fluoride, which becomes perfluoropolyether after being sent to the subsequent process for peroxidation treatment and end-capping. Part of the vaporized hexafluoropropylene is condensed and sent to the hexafluoropropylene storage tank 11 as raw material for adding to the photocatalytic oxidation reactor 1.

[0061] During the reaction, fluorine fluid is added every 3 hours. When adding fluorine fluid, the fluorine fluid feed valve 18 and the material pump 12 are simultaneously opened, with the pump speed controlled at 25 Hz. At the start of the reaction, the gas phase outlet 6, reflux port 7, and condenser 16 on the photocatalytic oxidation reactor 1 are opened, controlling the condensation temperature at -55℃. The reflux regulating valve 17 is adjusted to maintain a constant liquid level in the condenser 16. Before the end of the reaction and before the start of the next reaction, the nitrogen vent valve 21 is opened to continue nitrogen protection for the photocatalytic oxidation reactor 1.

[0062] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 1 below.

[0063] Table 1

[0064] hexafluoropropylene One-time feeding 800Kg Fluorine fluid Pump speed is 25Hz 50kg oxygen air velocity is 5 kg / h 75Kg

[0065] The reaction conversion efficiency and yield were calculated based on the perfluoropolyether fluoride yield obtained from a single reactor, as shown in Table 2 below.

[0066] Table 2

[0067]

[0068] Example 3:

[0069] The control process in this embodiment is the same as in Embodiment 2, with the only difference being slight variations in the specific control parameters. Specifically, in the photocatalytic oxidation reactor 1, the pressure gauge pressure is set to 0.5 MPa, the temperature probe temperature is set to -30°C, the stirring frequency of the stirrer 3 is 30 Hz (upper) and 15 Hz (lower), and the UV lamp wattage is 10000W. The reaction time is controlled at 10 hours, and fluorine fluid is added every 2.5 hours during the reaction.

[0070] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 3 below.

[0071] Table 3

[0072] hexafluoropropylene One-time feeding 600Kg Fluorine fluid Pump speed is 30Hz 48Kg oxygen air velocity is 3 kg / h 30Kg

[0073] The reaction conversion efficiency and yield were calculated based on the perfluoropolyether fluoride yield obtained from a single reactor, as shown in Table 4 below.

[0074] Table 4

[0075]

[0076] Example 4:

[0077] The control process in this embodiment is the same as in Embodiment 2, with the only difference being slight variations in the specific control parameters. Specifically, in the photocatalytic oxidation reactor 1, the pressure gauge pressure is set to 0.35 MPa, the temperature probe temperature is set to -32°C, the stirring frequency of the stirrer 3 is 20 Hz (upper) and 10 Hz (lower), and the UV lamp wattage is 8000W. The reaction time is controlled at 12 hours, and fluorine fluid is added every 4 hours during the reaction.

[0078] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 5 below.

[0079] Table 5

[0080] hexafluoropropylene One-time feeding 650Kg Fluorine fluid The pump speed is 5Hz. 30Kg oxygen The air velocity is 5 kg / h. 60Kg

[0081] The reaction conversion efficiency and yield were calculated based on the perfluoropolyether fluoride yield obtained from a single reactor, as shown in Table 6 below.

[0082] Table 6

[0083]

[0084] Example 5:

[0085] The control process in this embodiment is the same as in Embodiment 2, with the only difference being slight variations in the specific control parameters. Specifically, in the photocatalytic oxidation reactor 1, the pressure gauge pressure is set to 0.5 MPa, the temperature probe temperature is set to -30°C, the stirring frequency of the stirrer 3 is 25 Hz (upper) and 10 Hz (lower), and the UV lamp wattage is 15000W. The reaction time is controlled at 8 hours, and fluorine fluid is added every 4 hours during the reaction.

[0086] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 7 below.

[0087] Table 7

[0088] hexafluoropropylene One-time feeding 100Kg Fluorine fluid The pump speed is 5Hz. 5Kg oxygen The air velocity is 2 kg / h. 16Kg

[0089] The reaction conversion efficiency and yield were calculated based on the perfluoropolyether fluoride yield obtained from a single reactor, as shown in Table 8 below.

[0090] Table 8

[0091]

[0092] Example 6:

[0093] The control process in this embodiment is the same as in Embodiment 2, with the only difference being slight variations in the specific control parameters. Specifically, in the photocatalytic oxidation reactor 1, the pressure gauge pressure is set to 0.45 MPa, the temperature probe temperature is set to -29°C, the stirring frequency of the stirrer 3 is 30 Hz (upper) and 12 Hz (lower), and the UV lamp wattage is 12000W. The reaction time is controlled at 6 hours, and fluorine fluid is added every 3 hours during the reaction.

[0094] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 9 below.

[0095] Table 9

[0096] hexafluoropropylene One-time feeding 200kg Fluorine fluid The pump speed is 10Hz. 15kg oxygen The air velocity is 3 kg / h. 18Kg

[0097] The reaction conversion efficiency and yield were calculated based on the product (perfluoropolyether fluoride) yield obtained from a single reactor, as shown in Table 10 below.

[0098] Table 10

[0099]

[0100] Comparative Example 1:

[0101] This comparative example uses the same industrial control system as Example 1, but no fluorine fluid is introduced during the preparation process. The rest of the control process is the same as in Example 6, with only slight adjustments to the control parameters. Specifically, the pressure on the photocatalytic oxidation reactor 1 is controlled at 0.42 MPa, the temperature detected by the temperature probe is at -29°C, the stirring frequency of the stirrer 3 is 30 Hz (upper) and 12 Hz (lower), and the wattage of the ultraviolet lamp is 12000W. The reaction time is controlled at 6 hours.

[0102] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 11 below.

[0103] Table 11

[0104] hexafluoropropylene One-time feeding 200kg Fluorine fluid — 0kg oxygen The air velocity is 3 kg / h. 18kg

[0105] The reaction conversion efficiency and yield were calculated based on the product (perfluoropolyether fluoride) yield obtained from a single reactor, as shown in Table 12 below.

[0106] Table 12

[0107]

[0108]

[0109] Comparative Example 2:

[0110] This comparative example uses the same industrial control system as Example 1. However, during the preparation process, after nitrogen purging, the hexafluoropropylene feed valve 19, the fluorine fluid feed valve 18, and the material pump 12 are simultaneously opened. The material pump 12 pumps the hexafluoropropylene raw material from the hexafluoropropylene storage tank 11 and the fluorine fluid from the fluorine fluid storage tank 10 into the photocatalytic oxidation reactor 1 in one go. After the feeding is completed, the hexafluoropropylene feed valve 19, the fluorine fluid feed valve 18, and the material pump 12 are closed, and then the photocatalytic oxidation reactor 1 is started. The remaining control process is the same as in Example 5, with only slight adjustments to the control parameters. Specifically, the pressure gauge on the photocatalytic oxidation reactor 1 is set at 0.55 MPa, the temperature probe detects a temperature of -30°C, the stirring frequency of the stirrer 3 is 25 Hz (upper) and 10 Hz (lower), and the UV lamp wattage is 15000W. The reaction time is controlled at 8 hours.

[0111] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 13 below.

[0112] Table 13

[0113] hexafluoropropylene One-time feeding 100Kg Fluorine fluid Feeding is done in one go, and it is fed together with hexafluoropropylene. 5Kg oxygen The air velocity is 2 kg / h. 16Kg

[0114] The reaction conversion efficiency and yield were calculated based on the product (perfluoropolyether fluoride) obtained from a single reactor, as shown in Table 14 below.

[0115] Table 14

[0116]

[0117] Comparative Example 3:

[0118] This comparative example uses the same industrial control system as Example 1, but in the preparation process, fluorine fluid is introduced only during the reaction. Specifically, after hexafluoropropylene raw material is introduced into photocatalytic oxidation reactor 1 once, photocatalytic oxidation reactor 1 is started, oxygen is introduced to carry out the reaction, and after 3 hours of reaction, fluorine fluid is introduced once. The corresponding control process is the same as in Example 2, with only slight adjustments to the control parameters. Specifically, the pressure gauge on photocatalytic oxidation reactor 1 is controlled at 0.28 MPa, the temperature probe detects the temperature at -30°C, the stirring frequency of stirrer 3 is 22 Hz (upper) and 15 Hz (lower), and the wattage of the ultraviolet lamp is 10000W. The reaction time is controlled at 15 hours.

[0119] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 15 below.

[0120] Table 15

[0121] hexafluoropropylene One-time feeding 800Kg Fluorine fluid Feeding is done all at once after 3 hours of reaction. 50kg oxygen The air velocity is 5 kg / h. 75Kg

[0122] The reaction conversion efficiency and yield were calculated based on the product (perfluoropolyether fluoride) yield obtained from a single reactor, as shown in Table 16 below.

[0123] Table 16

[0124]

[0125] Comparative Example 4:

[0126] This comparative example uses a conventional photocatalytic oxidation reactor 1 for the preparation process, such as... Figure 3 As shown, the reactor is equipped with only an ultraviolet lamp 2 and a stirrer 3. The stirrer 3 is a common paddle stirrer, and it is operated according to the same process as Comparative Example 1, with only slight adjustments to the control parameters. Specifically, the pressure on the reactor is controlled at 0.45 MPa, the temperature detected by the temperature probe is at -31℃, the stirring frequency of the stirrer 3 is 35 Hz, and the wattage of the ultraviolet lamp is 12000W. The reaction time is controlled at 6 hours.

[0127] In the photocatalytic oxidation reactor 1, the material feed rate is implemented according to Table 17 below.

[0128] Table 17

[0129] hexafluoropropylene One-time feeding 200Kg Fluorine fluid — 0Kg oxygen The air velocity is 3 kg / h. 18Kg

[0130] The reaction conversion efficiency and yield were calculated based on the product (perfluoropolyether fluoride) yield obtained from a single reactor, as shown in Table 18 below.

[0131] Table 18

[0132]

[0133] As can be seen from the data of Examples 1 to 6 and Comparative Examples 1 to 4 above, the present invention, due to the use of... Figure 1 The photocatalytic oxidation reactor 1 shown is equipped with... Figure 2 The industrial control process shown is automated and can meet the requirements of the efficient production process of perfluoropolyether fluoride by photocatalytic oxidation of hexafluoropropylene and oxygen. It can achieve a single-pass conversion rate of over 70% for hexafluoropropylene and a single-pass yield of over 90% for hexafluoropropylene.

[0134] Although Comparative Example 1 used the same photocatalytic oxidation reactor 1, no fluorine fluid was added as a solvent during the control process, which significantly reduced the synthesis efficiency of perfluoropolyether fluoride. As shown in Table 12, the single-pass conversion percentage of hexafluoropropylene in Comparative Example 1 was only 58.4%, and the single-pass yield of hexafluoropropylene was only 81%.

[0135] Although Comparative Examples 2 and 3 used the same photocatalytic oxidation reactor 1, the method of adding fluorine fluid was changed in the control process. Although the corresponding fluorine fluid was added as a solvent, it still affected the synthesis efficiency of perfluoropolyether fluoride. As shown in Table 14, the single-pass conversion percentage of hexafluoropropylene in Comparative Example 2 was only 66%, and the single-pass yield of hexafluoropropylene was only 87.5%. As shown in Table 16, the single-pass conversion percentage of hexafluoropropylene in Comparative Example 3 was only 67.4%, and the single-pass yield of hexafluoropropylene was only 85.9%.

[0136] Comparative Example 4 used a conventional photocatalytic oxidation reactor 1, and no fluorine fluid was added as a solvent during the control process, which significantly reduced the synthesis efficiency of perfluoropolyether fluoride. As shown in Table 18, the single-pass conversion percentage of hexafluoropropylene in Comparative Example 4 was only 44%, and the single-pass yield of hexafluoropropylene was only 77%.

[0137] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. An industrial control method for the efficient synthesis of perfluoropolyether fluoride, characterized in that: Perfluoropolyether fluoride is prepared by reacting hexafluoropropylene and oxygen in a photocatalytic oxidation reactor (1). The photocatalytic oxidation reactor (1) is equipped with an ultraviolet lamp (2), a stirrer (3), and a gas distributor (4). The upper part of the photocatalytic oxidation reactor (1) is equipped with a liquid inlet (5), a gas outlet (6), and a reflux outlet (7). The lower part of the photocatalytic oxidation reactor (1) is equipped with a gas inlet (8) and a discharge outlet (9). The gas distributor (4) is installed above the gas inlet (8) and is located at the bottom of the photocatalytic oxidation reactor (1). Hexafluoropropylene from the hexafluoropropylene storage tank (11) and perfluoropolyether from the fluorine fluid storage tank (10) are fed into the photocatalytic oxidation reactor (1) via the material pump (12) through the liquid inlet (5). Oxygen from the oxygen storage tank (13) and nitrogen from the nitrogen storage tank (14) are metered by the gas flow meter (15) and fed into the photocatalytic oxidation reactor (1) through the gas inlet (8) and the gas distributor (4). Unreacted hexafluoropropylene is sent to the condenser (16) through the gas phase outlet (6) to be condensed into liquid phase and then returned to the photocatalytic oxidation reactor (1) through the reflux port (7). The reaction process should include at least the following control methods: (I) Control the opening time of the hexafluoropropylene feed valve (19) between the hexafluoropropylene storage tank (11) and the material pump (12) so that hexafluoropropylene is fed into the photocatalytic oxidation reactor (1) in one go through the material pump (12); (II) Control the opening time of the fluorine fluid feed valve (18) between the fluorine fluid storage tank (10) and the material pump (12) and the pumping speed of the material pump (12) so that the perfluoropolyether is intermittently fed into the photocatalytic oxidation reactor (1); (III) Control the opening time and oxygen flow rate of the oxygen inlet valve (20) between the oxygen storage tank (13) and the gas flow meter (15) so that the oxygen is continuously fed into the photocatalytic oxidation reactor (1); (IV) Control the opening time of the nitrogen inlet valve (21) between the nitrogen storage tank (14) and the gas flow meter (15); (V) Control the wattage of the ultraviolet lamp, the speed of the stirrer, the pressure of the pressure gauge, the temperature detected by the temperature probe and the reaction time on the photocatalytic oxidation reactor (1); (VI) Control the opening time and valve position of the reflux regulating valve (17) between the reflux port (7) and the condenser (16).

2. The industrial control method according to claim 1, characterized in that: The amount of hexafluoropropylene fed is controlled between 50 and 800 kg.

3. The industrial control method according to claim 1, characterized in that: In the photocatalytic oxidation reactor (1), perfluoropolyether is added for the first time after the hexafluoropropylene is fed and before the oxygen is introduced. Then, perfluoropolyether is added once every 3 to 10 hours during the reaction. When perfluoropolyether is added, the pumping speed of the material pump (12) is controlled to be 5 to 30 Hz, and the total amount of perfluoropolyether added is controlled to be 5 to 50 kg.

4. The industrial control method according to claim 1, characterized in that: The nitrogen gas is sent into the photocatalytic oxidation reactor (1) for nitrogen purging before feeding. After the reaction is completed and the material is discharged, the nitrogen gas protection for the photocatalytic oxidation reactor (1) is turned on.

5. The industrial control method according to claim 1, characterized in that: The stirrer (3) includes at least two stirring blades of different heights. The stirring blades are used for differential stirring, and the rotation speed of the stirring blades is controlled between 5 and 50 Hz.

6. The industrial control method according to claim 1, characterized in that: The wattage of the ultraviolet lamp is controlled between 8000W and 15000W, the pressure of the pressure gauge is controlled between 0 and 0.5MPa, the temperature detected by the temperature probe is controlled between -32 and -28℃, and the reaction time is controlled between 1 and 15h.

7. The industrial control method according to claim 1, characterized in that: The temperature detected by the temperature probe on the condenser (16) is controlled between -60 and -50℃.

8. The industrial control method according to claim 1, characterized in that: The opening time and valve position of the reflux regulating valve (17) are controlled according to the liquid level of the condenser (16).

9. A system applicable to the industrial control method according to any one of claims 1 to 8, characterized in that: It includes a photocatalytic oxidation reactor (1), a hexafluoropropylene storage tank (11), a fluorine fluid storage tank (10), an oxygen storage tank (13), a nitrogen storage tank (14), a material pump (12), a gas flow meter (15), and a condenser (16). The photocatalytic oxidation reactor (1) is equipped with an ultraviolet lamp (2), a stirrer (3) and a gas distributor (4). The upper part of the photocatalytic oxidation reactor (1) is equipped with a liquid inlet (5), a gas phase outlet (6) and a reflux outlet (7). The lower part of the photocatalytic oxidation reactor (1) is equipped with a gas inlet (8) and a discharge outlet (9). The gas inlet (8) is connected to the gas distributor (4) and is located at the bottom of the photocatalytic oxidation reactor (1). The hexafluoropropylene storage tank (11) is connected to the liquid inlet (5) of the photocatalytic oxidation reactor (1) via a material pump (12), and a hexafluoropropylene feed valve (19) is installed on the pipeline between the hexafluoropropylene storage tank (11) and the material pump (12). The fluorine fluid storage tank (10) is connected to the liquid inlet (5) of the photocatalytic oxidation reactor (1) via a material pump (12), and a fluorine fluid inlet valve (18) is provided on the pipeline between the fluorine fluid storage tank (10) and the material pump (12). The oxygen storage tank (13) is connected to the gas inlet (8) of the photocatalytic oxidation reactor (1) via a gas flow meter (15), and an oxygen inlet valve (20) is installed on the pipeline between the oxygen storage tank (13) and the gas flow meter (15). The nitrogen storage tank (14) is connected to the gas inlet (8) of the photocatalytic oxidation reactor (1) via a gas flow meter (15), and a nitrogen gas valve (21) is installed on the pipeline between the nitrogen storage tank (14) and the gas flow meter (15). The condenser (16) is connected to the gas phase outlet (6) and reflux port (7) of the photocatalytic oxidation reactor (1), and a reflux regulating valve (17) is provided on the pipeline between the condenser (16) and the reflux port (7).

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