Method for preparing octafluorocyclobutane through electrolysis of dichlorohexafluorocyclobutane

Abstract

The invention belongs to the field of electronic special gases, and particularly relates to a method for preparing octafluorocyclobutane through electrolysis of dichlorohexafluorocyclobutane. The method specifically comprises the following steps: S1, preparing an electrolyte: uniformly mixing potassium fluoride and anhydrous hydrogen fluoride according to a molar ratio of 1: 1-1: 15, performing dehydration treatment to obtain a mixed solution, and adding the mixed solution into an electrolytic bath; and S2, octafluorocyclobutane is prepared through electrolysis, specifically, dichlorohexafluorocyclobutane is dewatered and then added into the mixed solution to be evenly mixed, heating and electrifying are conducted, a crude product octafluorocyclobutane is obtained, the adding amount of dichlorohexafluorocyclobutane is 5-15% of the mass of the mixed solution, the heating temperature is 5-25 DEG C, the electrifying voltage is 4-20 V, and the current is 12-45 A. According to the method, the dichlorohexafluorocyclobutane is selected as the electrolysis raw material, octafluorocyclobutane is prepared through electrolysis, the conversion rate of the raw material is increased, waste of unreacted raw materials is reduced, and therefore the production cost is reduced.

Description

Technical Field

[0001] The present application belongs to the field of electronic special gases, and specifically relates to a method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane. Background Art

[0002] Dichlorohexafluorocyclobutane can be used in medical anesthesia and anesthesiology research, and can also be used as an organic synthesis intermediate. However, the main by-product of the thermal cracking process of chlorotrifluoroethylene, dichlorohexafluorocyclobutane, has low utilization value and high output, which restricts the economic efficiency of this process. 4 F 8 )RC-318, CAS115-25-3, is a perfluorinated derivative of cyclobutane, with a boiling point of -6.04°C and a relative vapor density (g / ml, air = 1): 7.0. At room temperature and atmospheric pressure, octafluorocyclobutane exists as a colorless, odorless gas at room temperature and pressure, and is a non-flammable gas.

[0003] With the development of semiconductor and microelectronics industries, environmental protection requirements are increasing day by day, and the requirements for electronic special gases are also increasing dramatically. Many electronic gases with greenhouse effects and serious ozone damage are gradually withdrawing from the market. Due to its low global warming potential (GWP) and zero ozone depletion potential (ODP), octafluorocyclobutane can be used as a green and environmentally friendly gas as a refrigerator, insulating gas, solvent, foaming agent, etchant, cleaning agent, etc., and is used in refrigeration, electricity, chemical industry, semiconductor and other industries. High-purity octafluorocyclobutane is an electronic gas that can be used in large-scale integrated circuit etching and cleaning in the semiconductor industry. As the scale of my country's electronic information industry continues to expand, its demand continues to grow, and the octafluorocyclobutane industry has broad development prospects.

[0004] The methods for preparing octafluorocyclobutane from dichlorohexafluorocyclobutane are currently reported as follows:

[0005] A Chinese patent with announcement number CN118530087A discloses a method for catalytically synthesizing octafluorocyclobutane, which uses a homemade catalyst, immerses a foamed metal in an immersion liquid to obtain a solid mixture; and calcines the solid mixture to obtain a crude catalyst. However, the catalyst in this method easily enters the channel along with the product as the reaction proceeds, which not only causes a waste of the catalyst, but also may clog the pipeline of the preparation device due to the catalyst, making subsequent cleaning difficult.

[0006] The Chinese patent with the announcement number CN114956950B discloses a method for synthesizing octafluorocyclobutane by using a fluorine-chlorine exchange reaction, wherein hydrogen fluoride gas and 1,1,2,2,3,4-hexafluoro-3,4-dichlorocyclobutane gas are introduced into a reactor equipped with an activated carbon-supported Cr2O3-NiO catalyst to react and obtain octafluorocyclobutane. However, the preparation process of the catalyst is cumbersome.

[0007] A Chinese patent with announcement number CN107721810B discloses a method for synthesizing octafluorocyclobutane by using 1,2-dichloro-3,3,4,4-tetrafluorocyclobutene with chlorine and hydrogen fluoride through addition reaction and substitution reaction. The raw materials of this method are relatively cheap and the reaction conditions are relatively mild. However, chlorine is highly corrosive to metals and easily causes corrosion and leakage of equipment. It is highly toxic and has serious environmental hazards, which limits the application of this method in industry. Summary of the invention

[0008] In view of the problems of low yield, unsatisfactory catalytic effect, complex reaction, etc. in the prior art, the present application provides a method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane. The method is simple to operate, safe, environmentally friendly and can run smoothly, avoids the selection of catalysts, ensures that the reaction maintains high yield while avoiding waste of raw materials and improving yield.

[0009] The technical solution of this application is as follows:

[0010] A method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane comprises the following steps:

[0011] Step S1. Preparation of electrolyte

[0012] Potassium fluoride and anhydrous hydrogen fluoride are mixed uniformly in a molar ratio of 1:1 to 1:15, and dehydrated to obtain a mixed solution, and the mixed solution is added to an electrolytic cell;

[0013] Step S2. Preparation of octafluorocyclobutane by electrolysis

[0014] First, dichlorohexafluorocyclobutane is removed from water and then added to the mixed solution, and then heated and powered on to obtain crude octafluorocyclobutane, wherein the amount of dichlorohexafluorocyclobutane added is 5-15% of the mass of the mixed solution, the heating temperature is 5-25° C., the power-on voltage is 4-20V, and the current is 12-45A;

[0015] Among them, the electrolytic cell in step S1 is provided with a plurality of cathode electrode plates and anode electrode plates distributed alternately along a linear array, and the electrode plates are all arranged vertically; insulating materials are padded between adjacent cathode electrode plates and anode electrode plates; circular holes for electrolyte circulation are evenly opened on the cathode electrode plates and anode electrode plates, and the diameter of the circular holes is 1 to 10 mm; the spacing between two adjacent circular holes on the same electrode plate is 5 to 20 mm; the spacing between adjacent cathode plates and anode plates is 1 to 8 mm.

[0016] Preferably, the diameter of the circular hole is 3-5 mm; the distance between two adjacent circular holes on the same electrode plate is 5-10 mm; and the distance between adjacent cathode plates and anode plates is 2-3 mm.

[0017] Preferably, the insulating material comprises a plurality of polytetrafluoroethylene washers, which are evenly distributed on the side wall of the cathode electrode plate or the anode electrode plate and are used to separate the cathode electrode plate from the anode electrode plate, and the distance between two adjacent polytetrafluoroethylene washers is 2 to 3 mm.

[0018] Preferably, the molar ratio of potassium fluoride to anhydrous hydrogen fluoride is 1:1 to 1:8.

[0019] Preferably, the dehydration treatment has a power-on voltage of 5 V, a power-on current of 3 to 5 A, and a power-on time of 0.5 to 2 h.

[0020] Preferably, the dichlorohexafluorocyclobutane dehydration process is: dichlorohexafluorocyclobutane is adsorbed and dehydrated with an adsorbent material until the water content is reduced to below 10 ppm, and the adsorbent material is any one of 3A molecular sieve, 4A molecular sieve or 5A molecular sieve.

[0021] Preferably, the amount of dichlorohexafluorocyclobutane added is 5-8% of the mass of the mixed solution, the heating temperature is 10-20° C., the voltage is 4-7V, and the current is 25-37A.

[0022] Preferably, the steps further include:

[0023] Step S3: condense the crude octafluorocyclobutane at 0-5°C, and then pass it into a hydrogen fluoride removal tower to absorb hydrogen fluoride to obtain the product octafluorocyclobutane.

[0024] The beneficial effects of this application are as follows:

[0025] (1) The present application uses dichlorohexafluorocyclobutane as an electrolytic raw material to prepare octafluorocyclobutane by electrolysis. Compared with the traditional method, the conversion rate of the raw material is improved, the waste of unreacted raw materials is reduced, and the production cost is reduced. At the same time, the electrolysis process directly promotes the breaking and recombination of chemical bonds without the need for additional catalysts, further simplifying the production process and reducing cost investment.

[0026] (2) The electrolysis method of the present application significantly reduces waste emissions during the production process, especially the generation of harmful gases. By precisely controlling the electrolysis conditions and subsequent processing steps, such as condensation cooling and removal of hydrogen fluoride, the cleanliness and safety of the production environment are ensured, which is in line with the development concept of modern green chemistry.

[0027] (3) The present application rationally designs the electrolytic plates (anode electrode plates and cathode electrode plates), including the diameter and spacing of the circular holes, as well as the spacing between the cathode plate and the anode plate, which not only improves the electrolysis efficiency, but also enhances the fluidity and mixing effect of the electrolyte, which is beneficial to the uniform reaction, thereby improving the product yield.

[0028] In summary, the present invention avoids the use of complex reaction conditions and catalysts, making the operation process simpler and safer, achieving high-yield preparation of octafluorocyclobutane, while avoiding the waste of raw materials and improving the utilization rate of raw materials. DETAILED DESCRIPTION

[0029] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the specific implementation method, structure, characteristics and effects of the present application are described in detail below in combination with the preferred embodiments. It should be noted that the applicant has previously discovered through a large number of experiments that the aperture of the circular holes on the cathode electrode plate and the anode electrode plate, the distance between two adjacent circular holes in the cathode electrode plate or the anode electrode plate, and the adjacent anode electrode plates and cathode electrode plates have good electrolysis effects within the parameter range set in the present application.

[0030] Example 1

[0031] Electrolytic plate preparation:

[0032] Material preparation: Select nickel metal plates as cathode electrode plates and anode electrode plates, clean and dry the metal plates to ensure that the surface of the electrode plates is flat, free of rust and pollution.

[0033] Punching: Use a punching tool to evenly punch circular holes on the cathode electrode plate and the anode electrode plate. The diameter of the circular holes is 4 mm, and the spacing between the circular holes is maintained at 5 to 7 mm to ensure uniform distribution of the electrolyte and uniform transfer of current.

[0034] Cross arrangement: The cathode electrode plates and anode electrode plates with holes are cross-arranged, and the spacing between the cross-arranged cathode electrode plates and anode electrode plates is controlled at 2 to 3 mm to ensure a good spacing between the cathode and the anode to facilitate the flow and reaction of the electrolyte.

[0035] Insulation treatment: Insert a PTFE gasket made of insulating material between the cathode electrode plate and the anode electrode plate with a spacing of 2 to 3 mm to prevent short circuit during the electrolysis process.

[0036] Electrolyte preparation:

[0037] Mixed solution: According to the molar ratio of potassium fluoride to anhydrous hydrogen fluoride of 1:1, accurately weigh potassium fluoride and anhydrous hydrogen fluoride, pour into the electrolytic cell, and stir for 20 minutes.

[0038] Dehydration treatment: Place the mixed solution in an electrolytic cell, connect the power supply, adjust the voltage to 5V, the current to 3A, and continue to power on for 1 hour to ensure that the water in the mixed solution is removed.

[0039] Preparation of octafluorocyclobutane by electrolysis:

[0040] Dehydration of dichlorohexafluorocyclobutane: Pour dichlorohexafluorocyclobutane into a molecular sieve dehydration device, use 3A, 4A or 5A molecular sieves for adsorption dehydration treatment, use a detection instrument to detect the water content of dichlorohexafluorocyclobutane to be 5.8ppm, and proceed to the next step.

[0041] Adding dichlorohexafluorocyclobutane: add the dehydrated dichlorohexafluorocyclobutane into the dehydrated electrolyte at a ratio of 8% of the mass of the mixed solution, and stir thoroughly for 20 minutes.

[0042] Electrolysis condition setting: The reaction temperature is controlled at 10°C by adjusting the circulation volume of the refrigerant in the electrolytic cell jacket. At the same time, the voltage of the electrolytic cell is adjusted to within the range of 4 to 5V, and the current is controlled between 25A and 27A to ensure that the electrolysis reaction is carried out under stable conditions.

[0043] Electrolysis reaction: Turn on the power supply to start the electrolysis reaction. During the electrolysis process, the changes in reaction temperature and current are monitored in real time to ensure that the reaction proceeds smoothly under the set conditions.

[0044] Collecting crude product: After the electrolysis reaction is completed, collect the gas produced by the reaction, which is the crude octafluorocyclobutane.

[0045] Post-processing:

[0046] Condensation and cooling: The collected crude octafluorocyclobutane gas is condensed and cooled through a condenser at 0-5°C.

[0047] Removal of hydrogen fluoride: The condensed gas is further processed through a hydrogen fluoride removal tower, which is filled with sodium fluoride particles to remove components such as hydrogen fluoride.

[0048] Collect the product: collect the gas after removing the hydrogen fluoride into a cold trap to obtain the product octafluorocyclobutane.

[0049] Example 2

[0050] Electrolytic plate preparation:

[0051] Material preparation: Select nickel metal plates as cathode electrode plates and anode electrode plates, clean and dry the metal plates to ensure that the surface of the electrode plates is flat, free of rust and pollution.

[0052] Punching: Use a punching tool to evenly punch circular holes on the cathode electrode plate and the anode electrode plate. The diameter of the circular holes is 3 mm, and the spacing between the circular holes is maintained at 9 to 10 mm to ensure uniform distribution of the electrolyte and uniform transfer of current.

[0053] Cross arrangement: The cathode electrode plates and anode electrode plates with holes are cross-arranged, and the spacing between the cross-arranged cathode electrode plates and anode electrode plates is controlled at 1 to 3 mm to ensure a good spacing between the cathode and the anode to facilitate the flow and reaction of the electrolyte.

[0054] Insulation treatment: Insert a PTFE gasket made of insulating material between the cathode electrode plate and the anode electrode plate with a spacing of 2 to 3 mm to prevent short circuit during the electrolysis process.

[0055] Electrolyte preparation:

[0056] Mixed solution: According to the molar ratio of potassium fluoride to anhydrous hydrogen fluoride of 1:3, accurately weigh potassium fluoride and anhydrous hydrogen fluoride, pour into the electrolytic cell, and stir for 20 minutes.

[0057] Dehydration treatment: Place the mixed solution in an electrolytic cell, connect the power supply, adjust the voltage to 5V, the current to 3A, and continue to power on for 2 hours to ensure that the water in the mixed solution is removed.

[0058] Preparation of octafluorocyclobutane by electrolysis:

[0059] Dehydration of dichlorohexafluorocyclobutane: Pour dichlorohexafluorocyclobutane into a molecular sieve dehydration device, use 3A, 4A or 5A molecular sieve for adsorption dehydration treatment, use a detection instrument to detect the water content of dichlorohexafluorocyclobutane to be 10ppm, and proceed to the next operation.

[0060] Adding dichlorohexafluorocyclobutane: add the dehydrated dichlorohexafluorocyclobutane into the dehydrated electrolyte at a ratio of 5% of the mass of the mixed solution, and stir thoroughly for 20 minutes.

[0061] Electrolysis condition setting: The reaction temperature is controlled at 10°C by adjusting the circulation volume of the refrigerant in the electrolytic cell jacket. At the same time, the voltage of the electrolytic cell is adjusted to the range of 5 to 7V, and the current is controlled between 27A and 35A to ensure that the electrolysis reaction is carried out under stable conditions.

[0062] Electrolysis reaction: Turn on the power supply to start the electrolysis reaction. During the electrolysis process, the changes in reaction temperature and current are monitored in real time to ensure that the reaction proceeds smoothly under the set conditions.

[0063] Collecting crude product: After the electrolysis reaction is completed, collect the gas produced by the reaction, which is the crude octafluorocyclobutane.

[0064] Post-processing:

[0065] Condensation and cooling: The collected crude octafluorocyclobutane gas is condensed and cooled through a condenser at 0-5°C.

[0066] Removal of hydrogen fluoride: The condensed gas is further processed through a hydrogen fluoride removal tower, which is filled with sodium fluoride particles to remove components such as hydrogen fluoride.

[0067] Collect the product: collect the gas after removing the hydrogen fluoride into a cold trap to obtain the product octafluorocyclobutane.

[0068] Example 3

[0069] Electrolytic plate preparation:

[0070] Material preparation: Select nickel metal plates as cathode electrode plates and anode electrode plates, clean and dry the metal plates to ensure that the surface of the electrode plates is flat, free of rust and pollution.

[0071] Punching: Use a punching tool to evenly punch circular holes on the cathode electrode plate and the anode electrode plate. The diameter of the circular holes is 5 mm, and the spacing between the circular holes is maintained at 7 to 9 mm to ensure uniform distribution of the electrolyte and uniform transfer of current.

[0072] Cross arrangement: The cathode electrode plates and anode electrode plates with holes are cross-arranged, and the spacing between the cross-arranged cathode electrode plates and anode electrode plates is controlled at 3 to 6 mm to ensure a good spacing between the cathode and the anode to facilitate the flow and reaction of the electrolyte.

[0073] Insulation treatment: Insert a PTFE gasket made of insulating material between the cathode electrode plate and the anode electrode plate with a spacing of 2 to 3 mm to prevent short circuit during the electrolysis process.

[0074] Preparation of electrolyte: Mixed solution: According to the molar ratio of potassium fluoride to anhydrous hydrogen fluoride of 1:8, accurately weigh potassium fluoride and anhydrous hydrogen fluoride, pour them into the electrolytic cell, and stir for 20 minutes.

[0075] Dehydration treatment: Place the mixed solution in an electrolytic cell, connect the power supply, adjust the voltage to 5V, the current to 3A, and continue to power on for 0.5 hours to ensure that the water in the mixed solution is removed.

[0076] Preparation of octafluorocyclobutane by electrolysis:

[0077] Dehydration of dichlorohexafluorocyclobutane: Pour dichlorohexafluorocyclobutane into a molecular sieve dehydration device, use 3A, 4A or 5A molecular sieve for adsorption dehydration treatment, use a detection instrument to detect the water content of dichlorohexafluorocyclobutane to be 8ppm, and proceed to the next step.

[0078] Adding dichlorohexafluorocyclobutane: add the dehydrated dichlorohexafluorocyclobutane into the dehydrated electrolyte at a ratio of 7% of the mass of the mixed solution, and stir thoroughly for 20 minutes.

[0079] Electrolysis condition setting: The reaction temperature is controlled at 10°C by adjusting the circulation volume of the refrigerant in the electrolytic cell jacket. At the same time, the voltage of the electrolytic cell is adjusted to the range of 5 to 6V, and the current is controlled between 35A and 37A to ensure that the electrolysis reaction is carried out under stable conditions.

[0080] Electrolysis reaction: Turn on the power supply to start the electrolysis reaction. During the electrolysis process, the changes in reaction temperature and current are monitored in real time to ensure that the reaction proceeds smoothly under the set conditions.

[0081] Collecting crude product: After the electrolysis reaction is completed, collect the gas produced by the reaction, which is the crude octafluorocyclobutane.

[0082] Post-processing:

[0083] Condensation and cooling: The collected crude octafluorocyclobutane gas is condensed and cooled through a condenser at 0-5°C.

[0084] Removal of hydrogen fluoride: The condensed gas is further processed through a hydrogen fluoride removal tower, which is filled with sodium fluoride particles to remove components such as hydrogen fluoride.

[0085] Collect the product: collect the gas after removing the hydrogen fluoride into a cold trap to obtain the product octafluorocyclobutane.

[0086] Example 4

[0087] Electrolytic plate preparation:

[0088] Material preparation: Select nickel metal plates as cathode electrode plates and anode electrode plates, clean and dry the metal plates to ensure that the surface of the electrode plates is flat, free of rust and pollution.

[0089] Punching: Use a punching tool to evenly punch circular holes on the cathode electrode plate and the anode electrode plate. The diameter of the circular holes is controlled within the range of 1 to 3 mm, and the spacing between the circular holes is maintained at 10 to 15 mm to ensure uniform distribution of the electrolyte and uniform transfer of current.

[0090] Cross arrangement: The cathode electrode plates and anode electrode plates with holes are cross-arranged, and the spacing between the cross-arranged cathode electrode plates and anode electrode plates is controlled at 6 to 8 mm to ensure a good spacing between the cathode and the anode to facilitate the flow and reaction of the electrolyte.

[0091] Insulation treatment: Insert a PTFE gasket made of insulating material between the cathode electrode plate and the anode electrode plate with a spacing of 2 to 3 mm to prevent short circuit during the electrolysis process.

[0092] Electrolyte preparation:

[0093] Mixed solution: According to the molar ratio of potassium fluoride to anhydrous hydrogen fluoride of 1:15, accurately weigh potassium fluoride and anhydrous hydrogen fluoride, pour into the electrolytic cell, and stir for 20 minutes.

[0094] Dehydration treatment: Place the mixed solution in an electrolytic cell, connect the power supply, adjust the voltage to 5V, the current to 3A, and continue to power on for 1 hour to ensure that the water in the mixed solution is removed.

[0095] Preparation of octafluorocyclobutane by electrolysis:

[0096] Dehydration of dichlorohexafluorocyclobutane: Pour dichlorohexafluorocyclobutane into a molecular sieve dehydration device, use 3A, 4A or 5A molecular sieve for adsorption dehydration treatment, use a detection instrument to detect the water content of dichlorohexafluorocyclobutane to be 10ppm, and proceed to the next step.

[0097] Adding dichlorohexafluorocyclobutane: add the dehydrated dichlorohexafluorocyclobutane into the dehydrated electrolyte at a ratio of 15% of the mass of the mixed solution, and stir thoroughly for 20 minutes.

[0098] Electrolysis condition setting: The reaction temperature is controlled at 10°C by adjusting the circulation volume of the refrigerant in the electrolytic cell jacket. At the same time, the voltage of the electrolytic cell is adjusted to the range of 8 to 10V, and the current is controlled between 12A and 17A to ensure that the electrolysis reaction is carried out under stable conditions.

[0099] Electrolysis reaction: Turn on the power supply to start the electrolysis reaction. During the electrolysis process, the changes in reaction temperature and current are monitored in real time to ensure that the reaction proceeds smoothly under the set conditions.

[0100] Collecting crude product: After the electrolysis reaction is completed, collect the gas produced by the reaction, which is the crude octafluorocyclobutane.

[0101] Post-processing:

[0102] Condensation and cooling: The collected crude octafluorocyclobutane gas is condensed and cooled through a condenser at 0-5°C.

[0103] Removal of hydrogen fluoride: The condensed gas is further processed through a hydrogen fluoride removal tower, which is filled with sodium fluoride particles to remove components such as hydrogen fluoride.

[0104] Collect the product: collect the gas after removing the hydrogen fluoride into a cold trap to obtain the product octafluorocyclobutane.

[0105] Example 5

[0106] Electrolytic plate preparation:

[0107] Material preparation: Select nickel metal plates as cathode electrode plates and anode electrode plates, clean and dry the metal plates to ensure that the surface of the electrode plates is flat, free of rust and pollution.

[0108] Punching: Use a punching tool to evenly punch circular holes on the cathode electrode plate and the anode electrode plate. The diameter of the circular holes is controlled within the range of 8 to 10 mm, and the spacing between the circular holes is maintained at 15 to 20 mm to ensure uniform distribution of the electrolyte and uniform transfer of current.

[0109] Cross arrangement: The cathode electrode plates and anode electrode plates with holes are cross-arranged, and the spacing between the cross-arranged cathode electrode plates and anode electrode plates is controlled at 6 to 8 mm to ensure a good spacing between the cathode and the anode to facilitate the flow and reaction of the electrolyte.

[0110] Insulation treatment: Insert a PTFE gasket made of insulating material between the cathode electrode plate and the anode electrode plate with a spacing of 2 to 3 mm to prevent short circuit during the electrolysis process.

[0111] Electrolyte preparation:

[0112] Mixed solution: According to the molar ratio of potassium fluoride to anhydrous hydrogen fluoride of 1:10, accurately weigh potassium fluoride and anhydrous hydrogen fluoride, pour into the electrolytic cell, and stir for 20 minutes.

[0113] Dehydration treatment: Place the mixed solution in an electrolytic cell, connect the power supply, adjust the voltage to 5V, the current to 3A, and continue to power on for 1 hour to ensure that the water in the mixed solution is removed.

[0114] Preparation of octafluorocyclobutane by electrolysis:

[0115] Dehydration of dichlorohexafluorocyclobutane: Pour dichlorohexafluorocyclobutane into the molecular sieve dehydration device, use 3A, 4A or 5A molecular sieve for adsorption dehydration treatment, use the detection instrument to detect the water content of dichlorohexafluorocyclobutane to be 7ppm, and proceed to the next step.

[0116] Adding dichlorohexafluorocyclobutane: add the dehydrated dichlorohexafluorocyclobutane into the dehydrated electrolyte at a ratio of 10% of the mass of the mixed solution, and stir thoroughly for 20 minutes.

[0117] Electrolysis condition setting: The reaction temperature is controlled at 10°C by adjusting the circulation volume of the refrigerant in the electrolytic cell jacket. At the same time, the voltage of the electrolytic cell is adjusted to the range of 17 to 20V, and the current is controlled between 40A and 45A to ensure that the electrolysis reaction is carried out under stable conditions.

[0118] Electrolysis reaction: Turn on the power supply to start the electrolysis reaction. During the electrolysis process, the changes in reaction temperature and current are monitored in real time to ensure that the reaction proceeds smoothly under the set conditions.

[0119] Collecting crude product: After the electrolysis reaction is completed, collect the gas produced by the reaction, which is the crude octafluorocyclobutane.

[0120] Post-processing:

[0121] Condensation and cooling: The collected crude octafluorocyclobutane gas is condensed and cooled through a condenser at 0-5°C.

[0122] Removal of hydrogen fluoride: The condensed gas is further processed through a hydrogen fluoride removal tower, which is filled with sodium fluoride particles to remove components such as hydrogen fluoride.

[0123] Collect the product: collect the gas after removing the hydrogen fluoride into a cold trap to obtain the product octafluorocyclobutane.

[0124] Comparative Example 1

[0125] The technical feature of this comparative example being different from Example 1 is that the molar ratio of potassium fluoride to anhydrous hydrogen fluoride in this comparative example is 1:20.

[0126] Comparative Example 2

[0127] The technical feature of this comparative example that is different from Example 1 is that the amount of dichlorohexafluorocyclobutane added in this comparative example is 25% of the mass of the mixed solution.

[0128] Comparative Example 3

[0129] The technical feature that distinguishes this comparative example from Example 1 is that the heating temperature of this comparative example is 3°C.

[0130] Comparative Example 4

[0131] The technical feature that distinguishes this comparative example from Example 1 is that the electrolysis voltage of this comparative example is 5V.

[0132] Performance Testing

[0133] The purity and yield of the octafluorocyclobutane obtained in Examples 1 to 4 and Comparative Examples 1 to 4 were tested, and the results are shown in Table 1.

[0134] Table 1

[0135] sample Product purity (%) Conversion rate (%) Example 1 86 54 Example 2 80 58 Example 3 83 68 Example 4 80 39 Comparative Example 1 56 37 Comparative Example 2 66 29 Comparative Example 3 63 35 Comparative Example 4 52 24

[0136] From the purity and yield of octafluorocyclobutane obtained in Examples 1 to 4 and Comparative Examples 1 to 4, it can be seen that within the parameter range set in the present application, the purity and yield of octafluorocyclobutane are relatively high, wherein the purity of the product can reach up to 86% and the yield can reach up to 68%.

[0137] The above is only a preferred embodiment of the present application and does not constitute any form of limitation to the present application. Although the present application has been disclosed as a preferred embodiment as above, it is not intended to limit the present application. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present application. However, any modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application are still within the scope of the technical solution of the present application.

Claims

1. A method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane, characterized in that: The steps include: Step S1. Preparation of electrolyte Potassium fluoride and anhydrous hydrogen fluoride are mixed uniformly in a molar ratio of 1:1 to 1:15, and dehydrated to obtain a mixed solution, and the mixed solution is added to an electrolytic cell; Step S2. Preparation of octafluorocyclobutane by electrolysis First, dichlorohexafluorocyclobutane is removed from water and then added to the mixed solution, and then heated and powered on to obtain crude octafluorocyclobutane, wherein the amount of dichlorohexafluorocyclobutane added is 5-15% of the mass of the mixed solution, the heating temperature is 5-25° C., the power-on voltage is 4-20V, and the current is 12-45A; Among them, the electrolytic cell in step S1 is provided with a plurality of cathode electrode plates and anode electrode plates distributed alternately along a linear array, and the electrode plates are all arranged vertically; insulating materials are padded between adjacent cathode electrode plates and anode electrode plates; circular holes for electrolyte circulation are evenly opened on the cathode electrode plates and anode electrode plates, and the diameter of the circular holes is 1 to 10 mm; the spacing between two adjacent circular holes on the same electrode plate is 5 to 20 mm; the spacing between adjacent cathode plates and anode plates is 1 to 8 mm.

2. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The diameter of the circular hole is 3-5 mm; the distance between two adjacent circular holes on the same electrode plate is 5-10 mm; the distance between adjacent cathode plates and anode plates is 2-3 mm.

3. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The insulating material includes a plurality of polytetrafluoroethylene gaskets, which are evenly distributed on the side wall of the cathode electrode plate or the anode electrode plate and are used to separate the cathode electrode plate from the anode electrode plate. The distance between two adjacent polytetrafluoroethylene gaskets is 2-3 mm.

4. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The molar ratio of potassium fluoride to anhydrous hydrogen fluoride is 1:1 to 1:

8.

5. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The dehydration treatment: the power-on voltage is 5V, the power-on current is 3-5A, and the power-on time is 0.5-2h.

6. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The dichlorohexafluorocyclobutane dehydration process is: dichlorohexafluorocyclobutane is adsorbed and dehydrated by an adsorption material until the water content is reduced to below 10 ppm, and the adsorption material is any one of 3A molecular sieve, 4A molecular sieve or 5A molecular sieve.

7. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The added amount of dichlorohexafluorocyclobutane is 5-8% of the mass of the mixed liquid, the heating temperature is 10-20° C., the voltage is 4-7V, and the current is 25-37A.

8. The method for preparing octafluorocyclobutane by electrolysis of dichlorohexafluorocyclobutane according to claim 1, characterized in that: The steps also include: Step S3: condense the crude octafluorocyclobutane at 0-5°C, and then pass it into a hydrogen fluoride removal tower to absorb hydrogen fluoride to obtain the product octafluorocyclobutane.