Preparation method of octafluorocyclopentene

Abstract

The invention discloses a preparation method of octafluorocyclopentene, which comprises the following two steps of: firstly, reacting 4-cyclopentene-1, 3-diketone with a selective fluorine reagent in acetonitrile under the condition of reflux to generate a crude product second mixture, purifying the second mixture, and putting the purified second mixture into a second-step reaction to obtain the octafluorocyclopentene. Reacting with diethylamino sulfur trifluoride in dichloromethane to generate a third mixture; the method has the advantages of environment-friendly and simple reaction process, no generation of three wastes, low cost, easy obtaining, simple reaction process, mild reaction, no generation of waste gas pollution even if nitrogen protection is needed, easy operation, and suitableness for industrial production.

Description

Technical Field

[0001] The invention belongs to the field of fine chemicals, and particularly relates to a method for preparing octafluorocyclopentene. Background Art

[0002] Octafluorocyclopentene is an important fine chemical product. Its high stability and inertness make it suitable for use as a solvent in certain anhydrous and oxygen-free reactions. Furthermore, it can be used as an electronic material due to its high electron affinity, forming a stable π-electron system with electron transport capabilities. It is widely used in the preparation of electronic materials, such as the synthesis of polymer electronic materials and the improvement of electrode materials. Furthermore, due to its excellent environmental and performance properties, it is used as a high-quality semiconductor etching and cleaning agent in fields such as integrated circuits. It is crucial for improving the performance and reliability of semiconductor devices and has a huge potential market and development prospects.

[0003] The industrial production method disclosed for the synthesis of octafluorocyclopentene is mainly the fluorine-chlorine exchange method (as shown in chemical reaction path 1). This process uses hexachlorocyclopentadiene as raw material, which is a highly toxic controlled drug and difficult to purchase. The first step of the preparation process uses chlorine and hydrogen fluoride, both of which are highly toxic and corrosive materials. The second step uses potassium fluoride, which is also a fluorine-containing corrosive material. Both steps are carried out under high temperature conditions, which makes the process highly dangerous and difficult to operate. At the same time, this process produces three wastes containing corrosive acidic gases, which require a large amount of alkali solution to absorb, causing great trouble for the treatment of the three wastes.

[0004] Chemical reaction pathway 1:

[0005] . Summary of the Invention

[0007] In view of the difficulties in procuring raw materials for preparing octafluorocyclopentene in the existing technology, the raw materials may also be highly toxic, and a large number of pollutants are generated during the reaction process. The present invention provides a method for preparing octafluorocyclopentene, which can avoid the use of highly toxic, highly corrosive and other hazardous materials and reduce the emission of three wastes.

[0008] The technical solution of the present invention is:

[0009] A method for preparing octafluorocyclopentene,

[0010] S1. Add 4-cyclopentene-1,3-dione and a selective fluorine reagent to solvent 1, heat to react, reflux and condense, cool to room temperature after the reaction, and quench with water;

[0011] S2. After quenching with water, the solution was extracted with ethyl acetate, and the organic phase was washed with a saturated sodium chloride solution, dried, and ethyl acetate was removed by distillation under reduced pressure to obtain a second crude mixture;

[0012] S3. The crude second mixture was purified by column chromatography, and the mobile phase was distilled off under reduced pressure to obtain a pure second mixture;

[0013] S4. The pure product of the second mixture reacts with diethylaminosulfur trifluoride in solvent 2 to form a third mixture.

[0014] Preferably, in S1, the solvent is dried in a dried 3A molecular sieve for not less than 16 hours before use to reduce the moisture content in the solvent to below 100 ppm;

[0015] 4-cyclopentene-1,3-dione and a selective fluorine reagent are added to a reactor containing solvent 1, and the gas in the reactor is replaced with nitrogen for more than 3 times to remove moisture and air from the reaction solution; the reaction is heated and stirred continuously during the reaction;

[0016] The condensation temperature during the reflux condensation process is between -30 and 10°C.

[0017] Preferably, in S1, the solvent 1 is one of acetonitrile, dichloromethane, carbon tetrachloride and dimethyl sulfoxide;

[0018] The first solvent is acetonitrile, the heating reaction temperature is maintained at 78-100°C, and the reaction time is 8-16 hours;

[0019] The first solvent is dichloromethane, the heating reaction temperature is maintained at 20°C to 40°C, and the reaction time is 16 to 46 hours;

[0020] The first solvent is carbon tetrachloride, the heating reaction temperature is 20°C to 78°C, and the reaction time is 8 to 32 hours;

[0021] The first solvent is dimethyl sulfoxide, the heating reaction temperature is 20-100°C, and the reaction time is 8-16 hours. 。

[0022] Preferably, in S1, the molar ratio of 4-cyclopentene-1,3-dione to the selective fluorine reagent is 1:(1.2-3);

[0023] The ratio of one volume mL of solvent to the mass g of 4-cyclopentene-1,3-dione is 10 to 50:1;

[0024] The volume ratio of solvent 1 to water is 1:1-5.

[0025] Preferably, in S2, the volume ratio of water to ethyl acetate for quenching is 1:1 to 15;

[0026] After quenching with water, the solution was extracted three times with ethyl acetate;

[0027] The volume ratio of saturated sodium chloride solution to ethyl acetate is 1:2-3;

[0028] The organic phase washed with saturated sodium chloride solution is dried with anhydrous sodium sulfate, and the usage ratio of the volume mL of saturated sodium chloride solution to the mass g of anhydrous sodium sulfate is 100:1-15.

[0029] The temperature of the reduced pressure distillation was 40°C and the vacuum degree was -0.1 MPa.

[0030] Preferably, in S3, purification is performed using a chromatography column, the mesh number of the silica gel is 200-1000 mesh; the mobile phase during the column chromatography purification process is a mixture of ethyl acetate and petroleum ether, and the volume ratio of ethyl acetate to petroleum ether is 1:50-200;

[0031] After purification, the mobile phase was evaporated to dryness using a rotary evaporator;

[0032] The temperature of the reduced pressure distillation was 40°C and the pressure was -0.1 MPa.

[0033] Preferably, the specific step of S4 is to add the second mixture to the solvent two and place it in an ice bath, the temperature of the ice bath is 0°C or below, add diethylaminosulfur trifluoride 1 to 5 drops per second to the ice bath reaction, start stirring, remove the ice bath, raise the temperature to 20-100°C, stir the reaction for 2-7h, condense and collect the condensate, and control the collection temperature of the condensate at 0°C or below. The condensate produced by the collected reaction is the third mixture, i.e., crude octafluorocyclopentene.

[0034] Preferably, in S4, the second solvent is one of dichloromethane, carbon tetrachloride, tetrahydrofuran and 1,4-dioxane.

[0035] Preferably, the second solvent is dichloromethane, and the reaction temperature is 20-40°C;

[0036] The second solvent is carbon tetrachloride, and the reaction temperature is 30-70°C;

[0037] The second solvent is tetrahydrofuran, and the reaction temperature is 20-66°C;

[0038] The second solvent is 1,4-dioxane, and the reaction temperature is 20-100°C.

[0039] Preferably, in S4, the molar ratio of the pure second mixture to diethylaminosulfur trifluoride is 1:(2-3);

[0040] The mass g of the second mixture and the volume g of the solvent mL The ratio is 1:10~50.

[0041] Reaction equation of the present invention is:

[0042]

[0043]

[0044] Beneficial effects of the present invention:

[0045] The process of the present invention has high safety, low production cost, strong process operability, less reaction waste, mild reaction conditions, and the solvent generated by the reaction and purification can be recycled. The reaction can be carried out under normal pressure, and the reaction yield is high.

[0046] In the present invention, the reactants react fully, the waste is easily discharged after the reaction is completed, the post-processing is simple, the solvent can be recycled, and the pollution during the synthesis process is reduced, which belongs to a green synthesis process.

[0047] The invention has low cost and high raw material utilization rate. Compared with the original traditional synthesis process, the present process does not involve high-risk and highly corrosive materials such as chlorine and hydrogen fluoride, and the reaction does not generate a large amount of acidic waste gas. This method adopts a two-step synthesis, the process route is short, the reaction process is relatively environmentally friendly and simple, and the solvent and purification reagent can be recycled. The raw materials used in the method of the present invention are common chemical raw materials, which are cheap and easily available. This reaction process is simple, the reaction is mild, no waste gas pollution is generated, it is easy to operate, and it is suitable for industrial production. DETAILED DESCRIPTION

[0048] Example 1

[0049] Step 1: Add 100 mL of dry acetonitrile to a 250 mL three-necked flask. Dry the acetonitrile in a 3A molecular sieve oven-dried container for 16 h to reduce the moisture content to below 100 ppm.

[0050] The raw material 4-cyclopentene-1,3-dione (9.6 g, 0.1 mol, 1 eq.) and the selective fluorine reagent (42.5 g, 0.12 mol, 1.2 eq.) were added to a three-necked reaction flask containing acetonitrile at 20°C. A condenser (condensation temperature 10°C) and a thermometer were added to the reaction flask. Three nitrogen ports were inserted into the condenser ports. The reactor was purged with nitrogen three times to remove moisture and air from the reaction solution.

[0051] The heating was turned on to heat the reaction flask to 81°C and the reaction was stirred for 16 hours.

[0052] Step 2: After the experiment is stopped, the temperature is lowered to room temperature, 100 mL of water is added to quench, and 300 mL of ethyl acetate is added to extract three times. The organic phases are combined and washed three times with 100 mL of saturated sodium chloride solution. The organic phase is dried over 15 g of anhydrous sodium sulfate and the ethyl acetate is removed by reduced pressure distillation at 40 ° C and pressure of -0.01 MPa.

[0053] Step three, purification by chromatography column, the silica gel powder used for purification has a mesh number of 200 mesh, the developing solvent mobile phase ratio (volume ratio) is ethyl acetate: petroleum ether = 1:50, and the purification is completed by rotary evaporation of the mobile phase mixed with ethyl acetate and petroleum ether to dryness to obtain 9.8 g of the second pure mixture with a purity of 85% and a yield of 70%.

[0054] Step 4: Add the purified second mixture (9.8 g, 0.07 mol, 1.0 eq.) to a two-necked flask containing 300 mL of dichloromethane, set up a distillation collection device, control the condensate temperature of the condenser at 0 ° C, place the two-necked flask in an ice bath (0 ° C), and slowly add diethylaminosulfur trifluoride (21.91 g, 0.14 mol, 2.0 eq.) to the reactor at 1 to 5 drops per second. Start stirring, remove the ice bath, gradually raise the temperature to 38 ° C, and stir for 5 hours.

[0055] The condensation temperature of the condenser was 0° C. 13.22 g of octafluorocyclopentene produced by the reaction was collected in a conical flask with a purity of 87.5% and a yield of 89.1%.

[0056] Example 2

[0057] Step 1: Add 1500 mL of dry dimethyl sulfoxide to a 2000 mL three-necked flask. Dry the dimethyl sulfoxide in a dried 3A molecular sieve for 16 h before use to reduce the moisture content of the dimethyl sulfoxide to below 100 ppm.

[0058] The raw material 4-cyclopentene-1,3-dione (19.2 g, 0.2 mol, 1 eq.) and the selective fluorine reagent (141.6 g, 0.4 mol, 2.0 eq.) were added to a three-necked reaction flask containing dimethyl sulfoxide at 20°C. A condenser (condensation temperature -30°C) and a thermometer were added to the reaction flask. Three nitrogen ports were inserted into the condenser ports. The reactor was purged with nitrogen three times to remove moisture and air from the reaction solution.

[0059] The heating was turned on to heat the reaction flask to 100°C and the reaction was stirred for 8 h.

[0060] Step 2: After the experiment is stopped, the mixture is cooled to room temperature, quenched by adding 3500 mL of water, and extracted three times with 6000 mL of ethyl acetate. The organic phases are combined and washed three times with 2000 mL of saturated sodium chloride solution. The organic phases are dried over 20 g of anhydrous sodium sulfate and the ethyl acetate is removed by distillation under reduced pressure.

[0061] Step three, purification by chromatography column, the silica gel powder used for purification has a mesh number of 1000 mesh, the developing solvent mobile phase ratio (volume ratio) is ethyl acetate: petroleum ether = 1:100, and the purification is completed by rotary evaporation at a temperature of 40 ° C and a pressure of -0.01 MPa to dryness of the mobile phase of ethyl acetate and petroleum ether to obtain 26.8 g of the second pure mixture with a purity of 91.2% and a yield of 95.7%.

[0062] Step 4. The purified second mixture (26.8 g, 0.19 mol, 1.0 eq.) was added to a 1000 mL two-necked flask containing 1,4-dioxane. A distillation collection device was set up. The condensate temperature of the condenser was controlled at -10 ° C. The two-necked flask was placed in an ice bath (0 ° C). Diethylaminosulfur trifluoride (59.47 g, 0.38 mol, 2.0 eq.) was slowly added to the reactor at a rate of 1 to 5 drops per second. Stirring was started, the ice bath was removed, the temperature was gradually raised to 68 ° C, and stirred for 2 h.

[0063] The condensation temperature of the condenser was -10°C, and 32.9 g of octafluorocyclopentene produced by the reaction was collected in a conical flask with a purity of 81.9% and a yield of 81.7%.

[0064] Example 3

[0065] Step 1: Add 3000 mL of dry carbon tetrachloride to a 5000 mL three-necked flask. Dry the carbon tetrachloride in a dried 3A molecular sieve for 16 hours before use to reduce the water content in the carbon tetrachloride to below 100 ppm.

[0066] The raw material 4-cyclopentene-1,3-dione (28.8 g, 0.3 mol, 1 eq.) and the selective fluorine reagent (318.6 g, 0.9 mol, 3.0 eq.) were added to a three-necked reaction flask containing carbon tetrachloride at 20°C. A condenser (condensation temperature 0°C) and a thermometer were added to the reaction flask. Three nitrogen ports were inserted into the condenser ports. The reactor was purged with nitrogen three times to remove moisture and air from the reaction solution.

[0067] The heating was turned on to heat the reaction flask to 78°C and the reaction was stirred for 12 h.

[0068] Step 2: After the experiment is stopped, the temperature is lowered to room temperature, 3500 mL of water is added to quench, and 6000 mL of ethyl acetate is added to extract three times. The organic phases are combined and washed three times with 3000 mL of saturated sodium chloride solution. The organic phase is dried over 30 g of anhydrous sodium sulfate and the ethyl acetate is removed by reduced pressure distillation at 40 ° C and pressure of -0.01 MPa.

[0069] Step three, purification by chromatography column, the silica gel powder used for purification has a mesh number of 800 mesh, the developing solvent mobile phase ratio (volume ratio) is ethyl acetate: petroleum ether = 1:200, and the purification is completed by rotary evaporation of the mobile phase mixed with ethyl acetate and petroleum ether to dryness to obtain 38.9 g of the second pure mixture with a purity of 89.7% and a yield of 92.6%.

[0070] Step 4: The purified second mixture (38.9 g, 0.28 mol, 1.0 eq.) was added to a two-necked flask containing 5000 mL of tetrahydrofuran. A distillation collection device was set up. The condensate temperature of the condenser was controlled at -20 ° C. The two-necked flask was placed in an ice bath (0 ° C). Diethylaminosulfur trifluoride (133.6 g, 0.83 mol, 3.0 eq.) was slowly added to the reactor at a rate of 1 to 5 drops per second. Stirring was started, the ice bath was removed, the temperature was gradually raised to 66 ° C, and stirred for 7 h.

[0071] The condensation temperature of the condenser was -20°C, and 46.9 g of octafluorocyclopentene produced by the reaction was collected in a conical flask with a purity of 72.3% and a yield of 79.1%.

[0072] Comparative Example 1

[0073] Step 1: Add the raw material 4-cyclopentene-1,3-dione (9.6 g, 0.1 mol, 1 eq.) and the selective fluorine reagent (42.5 g, 0.12 mol, 1.2 eq.) to a three-necked reaction flask containing undried acetonitrile at 20 ° C. The reaction flask is added with a condenser (condensation temperature 10 ° C.) and a thermometer. Three nitrogen ports are inserted into the condenser ports. The reactor is purged with nitrogen three times to remove moisture and air from the reaction solution.

[0074] The heating was turned on to heat the reaction flask to 81°C and the reaction was stirred for 16 hours.

[0075] Step 2: After the experiment is stopped, the mixture is cooled to room temperature, quenched with 100 mL of water, and extracted three times with 300 mL of ethyl acetate. The organic phases are combined and washed three times with 100 mL of saturated sodium chloride solution. The organic phases are dried over anhydrous sodium sulfate and the ethyl acetate is removed by distillation under reduced pressure.

[0076] Step three, purification by chromatography column, the silica gel powder used for purification has a mesh number of 200 mesh, the developing solvent mobile phase ratio (volume ratio) is ethyl acetate: petroleum ether = 1:50, the purification end temperature is 44 ° C and the pressure is -0.01 MPa. The mobile phase mixed with ethyl acetate and petroleum ether is evaporated to dryness using a rotary evaporator to obtain 6.2 g of the second pure mixture with a purity of 78.6% and a yield of 44.28%.

[0077] Step 4: Add the purified second mixture (6.2 g, 0.044 mol, 1.0 eq.) to a two-necked flask containing 300 mL of dichloromethane, set up a distillation collection device, control the condensate temperature of the condenser at 0 ° C, place the two-necked flask in an ice bath (0 ° C), and slowly add diethylaminosulfur trifluoride (13.77 g, 0.088 mol, 2.0 eq.) to the reactor at 1 to 5 drops per second. Start stirring, remove the ice bath, gradually raise the temperature to 38 ° C, and stir for 5 hours.

[0078] The condensation temperature of the condenser was 0° C. 6.9 g of octafluorocyclopentene produced by the reaction was collected in a conical flask with a purity of 81.5% and a yield of 73.9%.

[0079] Comparative Example 2

[0080] Step 1: Add 100 mL of dry acetonitrile to a 250 mL three-necked flask. Dry the acetonitrile in a 3A molecular sieve oven-dried container for 16 h to reduce the moisture content to below 100 ppm.

[0081] The raw material 4-cyclopentene-1,3-dione (9.6 g, 0.1 mol, 1 eq.) and the selective fluorine reagent (42.5 g, 0.12 mol, 1.2 eq.) were added to a three-necked reaction flask containing acetonitrile at 20°C. A condenser (condensation temperature 10°C) and a thermometer were added to the reaction flask, and three nitrogen ports were inserted into the condenser ports.

[0082] The heating was turned on to heat the reaction flask to 81°C and the reaction was stirred for 16 hours.

[0083] Step 2: After the experiment is stopped, the temperature is lowered to room temperature, 100 mL of water is added to quench, and 300 mL of ethyl acetate is added to extract three times. The organic phases are combined and washed three times with 100 mL of saturated sodium chloride solution. The organic phase is dried over 50 g of anhydrous sodium sulfate and the ethyl acetate is removed by reduced pressure distillation at 40 ° C and pressure of -0.01 MPa.

[0084] Step three, purification by chromatography column, the silica gel powder used for purification has a mesh number of 200 mesh, the developing solvent mobile phase ratio (volume ratio) is ethyl acetate: petroleum ether = 1:50, and the purification is completed by rotary evaporation of the mobile phase mixed with ethyl acetate and petroleum ether to dryness to obtain 7.7 g of the second mixture pure product with a purity of 80.1% and a yield of 55%.

[0085] Step 4: Add the purified second mixture (7.7 g, 0.055 mol, 1.0 eq.) to a two-necked flask containing 300 mL of dichloromethane, set up a distillation collection device, control the condensate temperature of the condenser at 0 ° C, place the two-necked flask in an ice bath (0 ° C), and slowly add diethylaminosulfur trifluoride (17.21 g, 0.11 mol, 2.0 eq.) to the reactor at 1 to 5 drops per second. Start stirring, remove the ice bath, gradually raise the temperature to 38 ° C, and stir for 5 hours.

[0086] The condensation temperature of the condenser was 0° C. 7.0 g of octafluorocyclopentene produced by the reaction was collected in a conical flask with a purity of 64.4% and a yield of 60.0%.

[0087] Comparative Example 3

[0088] Step 1: Add 100 mL of dry acetonitrile to a 250 mL three-necked flask. Dry the acetonitrile in a 3A molecular sieve oven-dried container for 16 h to reduce the water content to below 100 ppm.

[0089] The raw material 4-cyclopentene-1,3-dione (9.6 g, 0.1 mol, 1 eq.) and the selective fluorine reagent (42.5 g, 0.12 mol, 1.2 eq.) were added to a three-necked reaction flask containing acetonitrile at 20°C. A condenser (condensation temperature 10°C) and a thermometer were added to the reaction flask. Three nitrogen ports were inserted into the condenser ports. The reactor was purged with nitrogen three times to remove moisture and air from the reaction solution.

[0090] The heating was turned on to heat the reaction flask to 81°C and the reaction was stirred for 16 hours.

[0091] Step 2: After the experiment is stopped, the mixture is cooled to room temperature, quenched with 100 mL of water, and extracted three times with 300 mL of ethyl acetate. The organic phases are combined and washed three times with 100 mL of saturated sodium chloride solution. The organic phases are dried over anhydrous sodium sulfate and the ethyl acetate is removed by distillation under reduced pressure.

[0092] Step three, purification by chromatography column, the silica gel powder used for purification was 200 mesh, the developing solvent mobile phase ratio (volume ratio) was ethyl acetate: petroleum ether = 1:50, and the purification was completed by rotary evaporation of the mixed mobile phase of ethyl acetate and petroleum ether to dryness to obtain 7.3 g of the second pure mixture with a purity of 79.7% and a yield of 52.1%.

[0093] Step 4: Add the purified second mixture (7.3 g, 0.05 mol, 1.0 eq.) to a two-necked flask containing 300 mL of dichloromethane, set up a distillation collection device, do not put coolant in the condenser, condense with air at 25 ° C, slowly add diethylaminosulfur trifluoride (18.78 g, 0.12 mol, 2.0 eq.) to the reactor at 1 to 5 drops per second, start stirring, gradually raise the temperature to 38 ° C, and stir for 5 hours.

[0094] The reaction mixture was collected at 25° C. and 5.73 g of octafluorocyclopentene was collected in a conical flask with a purity of 68.5% and a yield of 54.05%.

[0095] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing octafluorocyclopentene, characterized in that: S1. Add 4-cyclopentene-1,3-dione and a selective fluorine reagent to solvent 1, heat to react, reflux and condense, cool to room temperature after the reaction, and add water to quench; S2. After quenching with water, the solution was extracted with ethyl acetate, the organic phase was washed with a saturated sodium chloride solution, dried, and the ethyl acetate was removed by distillation under reduced pressure to obtain a second crude mixture; S3. The crude second mixture is purified by column chromatography, and the mobile phase is distilled off under reduced pressure to obtain a pure second mixture; S4. The pure product of the second mixture is reacted with diethylaminosulfur trifluoride in solvent 2 to generate a third mixture.

2. The method for preparing octafluorocyclopentene according to claim 1, characterized in that: In S1, the solvent 1 is dried in a dried 3A molecular sieve for not less than 16 hours before use to reduce the moisture content of the solvent to less than 100 ppm; Add 4-cyclopentene-1,3-dione and a selective fluorine reagent into a reactor containing solvent 1, and replace the gas in the reactor with nitrogen for more than 3 times to remove moisture and air in the reaction solution; The heating reaction process is continued with stirring; The condensation temperature during the reflux condensation process is between -30 and 10°C.

3. The method for preparing octafluorocyclopentene according to claim 2, characterized in that: In S1, the solvent 1 is one of acetonitrile, dichloromethane, carbon tetrachloride and dimethyl sulfoxide; The first solvent is acetonitrile, the heating reaction temperature is maintained at 78-100°C, and the reaction time is 8-16h; The solvent 1 is dichloromethane, the heating reaction temperature is maintained at 20°C to 40°C, and the reaction time is 16 to 46 hours; The first solvent is carbon tetrachloride, the heating reaction temperature is 20°C to 78°C, and the reaction time is 8 to 32 hours; The first solvent is dimethyl sulfoxide, the heating reaction temperature is 20-100°C, and the reaction time is 8-16 hours. 。 4. The method for preparing octafluorocyclopentene according to claim 1, characterized in that: In S1, the molar ratio of 4-cyclopentene-1,3-dione:selective fluorine reagent is 1:(1.2-3); Solvent volume mL and 4-cyclopentene-1,3-dione mass g The ratio is 10 to 50:1; The volume ratio of solvent 1 to water is 1:1-5.

5. The method for preparing octafluorocyclopentene according to claim 1, characterized in that: In S2, the volume ratio of water to ethyl acetate for quenching with water is 1:1 to 15; After quenching with water, the solution was extracted three times with ethyl acetate; The volume ratio of saturated sodium chloride solution to ethyl acetate is 1:2-3; The organic phase washed with saturated sodium chloride solution is dried with anhydrous sodium sulfate, and the usage ratio of saturated sodium chloride solution volume mL to anhydrous sodium sulfate mass g is 100:1-15. The temperature of the reduced pressure distillation was 40°C and the vacuum degree was -0.1 MPa.

6. The method for preparing octafluorocyclopentene according to claim 1, characterized in that: In S3, purification is performed using a chromatography column, and the mesh number of silica gel powder is 200 to 1000 mesh; During column chromatography purification, the mobile phase is a mixture of ethyl acetate and petroleum ether, with a volume ratio of ethyl acetate to petroleum ether of 1:50 to 200; After purification, the mobile phase was evaporated using a rotary evaporator; The temperature of the reduced pressure distillation was 40°C and the pressure was -0.1 MPa.

7. The method for preparing octafluorocyclopentene according to claim 1, characterized in that: The specific steps of S4 are as follows: adding the second mixture to solvent two for ice bathing, the temperature of the ice bath is 0°C or below, adding diethylaminosulfur trifluoride 1 to 5 drops per second to the ice bath reaction, starting stirring, removing the ice bath, raising the temperature to 20-100°C, stirring the reaction for 2-7h, condensing and collecting the condensate, the collection temperature of the condensate is controlled at 0°C or below, and the condensate produced by the reaction is collected as the third mixture, i.e., crude octafluorocyclopentene.

8. The method for preparing octafluorocyclopentane according to claim 1, characterized in that: In S4, the second solvent is one of dichloromethane, carbon tetrachloride, tetrahydrofuran and 1,4-dioxane.

9. The method for preparing octafluorocyclopentane according to claim 8, characterized in that: The second solvent is dichloromethane, and the reaction temperature is 20-40°C; The second solvent is carbon tetrachloride, and the reaction temperature is 30-70°C; The second solvent is tetrahydrofuran, and the reaction temperature is 20-66°C; The second solvent is 1,4-dioxane, and the reaction temperature is 20-100°C.

10. The method for preparing octafluorocyclopentane according to claim 1, characterized in that: In S4, the molar ratio of the pure product of the second mixture to diethylaminosulfur trifluoride is 1:(2-3); The mass g of the second mixture and the volume g of the solvent mL The ratio is 1:10~50.

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