JP7411124B2 - Method for producing hexafluoro-1,3-butadiene and its intermediates - Google Patents

Description

The present invention relates to a fluorine-containing electron gas, and particularly to a method for synthesizing hexafluoro-1,3-butadiene and its intermediates by a telomerization method.

The English name of hexafluoro-1,3-butadiene is Hexafluoro-1,3-butadiene, the abbreviation is HFBD, the boiling point is 5.5°C, the freezing point is -130°C, and the liquid density at 15°C is 1.44 kg. /L. Hexafluoro-1,3-butadiene is a next-generation green dry etching gas with excellent environmental performance and work performance, with an ambient time (ALT) of only 1.9 days and a GWP ₁₀₀ value of 290. Hexafluoro-1,3-butadiene has a relatively low fluorocarbon ratio, so it exhibits excellent etching performance and is used for etching for Cu-containing and low-K dielectric constant rectifier circuit board production, mainly for device dimensions ( It is used for precision etching (accuracy up to 100 nm) in critical dimensions and has better selectivity and depth/width ratio than other etching gases. Hexafluoro-1,3-butadiene is a key etching gas for 3D NAND flash memory, the next generation storage technology, as one of the essential materials for producing high-end chips. As demand for high-end chips increases, the market for hexafluoro-1,3-butadiene will continue to expand.

In the prior art, there are mainly the following reports regarding the synthesis of hexafluoro-1,3-butadiene.

1) Process using chlorine gas and iodine as raw materials Patent Document 1 discloses a method for synthesizing hexafluoro-1,3-butadiene using chlorine gas and iodine as raw materials. 2. reacting chlorine gas and iodine to synthesize iodine chloride; Reacting trichlorovinyl chloride and iodine chloride to obtain 1,2-dichloro-1,1,2-trifluoro-2-iodoethane (CF ₂ Cl-CFICl); , 1,2-trifluoro-2-iodoethane are subjected to an intermolecular coupling reaction in the presence of a catalyst to form 1,2,3,4-tetrachloro-hexafluorobutane (CF ₂ Cl-CFCl-CFCl-CF ₂ Cl ) and 4. intramolecular dehalogenation of 1,2,3,4-tetrachloro-hexafluorobutane to obtain hexafluoro-1,3-butadiene. The reaction formula is as follows.
However, this method involves relatively long steps and uses expensive iodine chloride, resulting in relatively high raw material costs for the process.

2) Dimerization process Patent Document 2 discloses a method for synthesizing hexafluoro-1,3-butadiene using chlorotrifluoroethylene as a raw material, and the method involves subjecting chlorotrifluoroethylene to a dimerization reaction at a high temperature. 34% of 1,2-dichlorohexafluorocyclobutane and 27% of 3,4-dichlorohexafluoro-1-butene were obtained, and these two products were separated by a high efficiency rectification column. The method includes the step of directly dechlorinating 4-dichlorohexafluoro-1-butene with zinc powder to obtain the desired product hexafluoro-1,3-butadiene. The reaction formula is as follows.
However, this method requires high temperature and high pressure conditions for the polymerization reaction, and the reaction selectivity is only 27%.

3) Coupling process of zinc reagent Patent Document 3 uses trifluorobromoethylene as a raw material, reacts it with zinc powder to synthesize trifluorovinylzinc reagent, and then synthesizes the trifluorovinyl zinc reagent under the action of trivalent iron salt or divalent copper salt. discloses a method for obtaining hexafluoro-1,3-butadiene through a self-coupling reaction. The reaction formula is as follows.
However, this method has a problem with the origin of the starting material, trifluorobromoethylene.

4) Fluorination process of elemental fluorine Patent Document 4 discloses a method for synthesizing hexafluoro-1,3-butadiene using trichlorethylene (TCE) and fluorine gas as raw materials, and the method includes 1. Fluorine dimerization reaction: In an AISI 316L reactor, TCE was reacted with fluorine gas diluted with helium gas to obtain C ₄ H ₂ F ₂ Cl ₆ , the conversion rate of TCE was 22.9%, 2. Selectivity is 50%; Elimination reaction: In a glass reactor, C ₄ H ₂ F ₂ Cl ₆ was reacted with 20% NaOH solution to obtain tetrachlorodifluorobutadiene (CFCl=CCl-CCl=CFCl), with a reaction yield of 93%. A certain step; 3. Fluorination reaction: Tetrachlorohexafluorobutane (CF ₂ Cl-CFCl-CFCl-CF ₂ Cl, CFC-316) is obtained by reacting tetrachlorodifluorobutadiene with fluorine gas diluted with helium gas, and reaction conversion is performed. 4. efficiency is 97.8% and selectivity is 64%; Dehalogenation reaction: reacting CFC-316 with zinc powder in isopropanol solvent to obtain hexafluoro-1,3-butadiene, the yield is 96% and the product purity is 99.5%; ,including. However, this method has relatively high demands on the equipment and has high process safety risks.

Therefore, there is still a need to develop a new synthesis process for hexafluoro-1,3-butadiene.

China Patent Application Publication No. 106336342 Russian Patent No. 0118462 China Patent Application Publication No. 105732301 International Publication No. 2009/087067

In order to solve the above technical problems, the present invention proposes a method for producing hexafluoro-1,3-butadiene and its intermediates by telomerization method, which has a simple process and It is mild, produces a small amount of the "three wastes" (exhaust gas, waste water, and solid waste), is safe and environmentally friendly, and is suitable for industrial production.

The purpose of the present invention is achieved by the following technical solution.
A method for producing hexafluoro-1,3-butadiene, the method comprising:
A1. 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and trifluorohaloethylene are reacted in a polar aprotic solvent under the action of an initiator, and the reaction solution is purified to obtain 1 ,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane (intermediate A), the structural formula of the trifluorohaloethylene is: CF ₂ =CFX, where X is Cl, Br or I;
The initiators include azobisisobutyronitrile (AIBN), di-tert-butyl peroxide (DTBP), dibenzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl hydroperoxide (TBHP), and persulfuric acid. a step of at least one selected from potassium (KPS) and ammonium persulfate (APS);
A2. Dehalogenation reaction of 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane and zinc powder to produce hexafluoro-1,3-butadiene and obtaining.

In the present invention, different initiation modes (eg photoinitiation or initiator initiation) have a relatively large influence on the synthesis of intermediate A. In terms of reaction mechanism, step A1 can be considered as a radical reaction, but both photoinitiation and initiator initiation can initiate radical reactions. However, the applicant has found that the initiation effect of the initiator is much better than photoinitiation for the reaction of the A1 step, and the initiation effect also differs depending on the type of initiator. That is, by using an initiator, the selectivity of intermediate A can be improved. Preferably, the initiator is at least one selected from di-tert-butyl peroxide, dibenzoyl peroxide, and tert-butyl hydroperoxide. More preferably, the initiator is dibenzoyl peroxide or tert-butyl hydroperoxide.

Furthermore, the molar blending ratio of the 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and the initiator is 1:0.01 to 1:0.1. Preferably, the molar mixing ratio of the 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and the initiator is 1:0.03 to 1:0.06.

In the intermediate production process of Step A1 of the present invention, an aprotic polar solvent is more advantageous for the progress of the reaction. Preferably, the aprotic polar solvent is at least one selected from tetrahydrofuran, 1,4-dioxane, acetonitrile, diethylene glycol dimethyl ether, N,N-dimethylformamide, and N,N-dimethylacetamide. More preferably, the polar aprotic solvent is at least one selected from 1,4-dioxane, acetonitrile, and diethylene glycol dimethyl ether.
In the intermediate production process of Step A1 of the present invention, an inert gas atmosphere is more advantageous for the progress of the reaction. Preferably, the inert gas is at least one selected from nitrogen gas, helium gas, and argon gas.

In the intermediate production process of Step A1 of the present invention, the reaction solution may be purified by a conventional purification method such as atmospheric rectification or vacuum rectification.

In the hexafluoro-1,3-butadiene production process of step A2 of the present invention, the reaction can be carried out without a solvent. Of course, it is more effective to react in an organic solvent. Preferably, the organic solvent is formic acid, acetic acid, trifluoroacetic acid, propionic acid, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, 1,1,1-trichloroethane, isopropanol, tert-butanol, N,N-dimethylformamide, At least one selected from N,N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, and hexamethylphosphamide. More preferably, the organic solvent is at least one selected from acetic acid, N,N-dimethylformamide, and isopropanol.

In the hexafluoro-1,3-butadiene production process of step A2 of the present invention, the reaction progresses more favorably in the presence of a catalyst. Preferably, the catalyst is at least one selected from zinc chloride (ZnCl ₂ ), zinc bromide (ZnBr ₂ ), zinc iodide (ZnI ₂ ), simple iodine, and 1,2-dibromoethane; The molar mixing ratio of A and the catalyst is 1:0.01 to 1:0.1. More preferably, the molar blending ratio of intermediate A and catalyst is 1:0.03 to 1:0.06.

In the method for producing hexafluoro-1,3-butadiene of the present invention, it is preferable that the reaction temperature of the A1 step is 60°C to 200°C, the reaction is carried out for 1 to 12 hours, and the reaction temperature of the A2 step is 60°C to 200°C. The temperature is 40°C to 150°C, and the reaction is kept at a temperature of 1 to 24 hours.

More preferably, the reaction temperature in the A1 step is 80° C. to 160° C., and the reaction is carried out for 6 to 12 hours, and the reaction temperature in the A2 step is 60° C. to 90° C., and the reaction is carried out for 3 to 6 hours. .

The present invention further provides a method for producing 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane, the method comprising:
In a polar aprotic solvent, 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and trifluorohaloethylene are reacted in an inert gas atmosphere under the action of an initiator. a step of rectifying and purifying the liquid to obtain 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane, the step of obtaining 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane; The formula is CF ₂ =CFX, where X is Cl, Br or I;
The initiators include azobisisobutyronitrile (AIBN), di-tert-butyl peroxide (DTBP), dibenzoyl peroxide (BPO), dicumyl peroxide (DCP), tert-butyl hydroperoxide (TBHP), and persulfuric acid. The step includes at least one selected from potassium (KPS) and ammonium persulfate (APS).

Compared with the prior art, the beneficial effects of the present invention are as follows:
1. The present invention employs a telomerization reaction between 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and trifluorohaloethylene to produce an intermediate of hexafluoro-1,3-butadiene. However, the process is simple and the reaction conditions are mild, making it suitable for industrial production.
2. The present invention adopts a radical initiator to initiate the telomerization reaction, which not only can control the generation rate of radicals and the extent of the telomerization reaction, but also greatly improves the selectivity of intermediates compared to photoinitiation. be able to.

The present invention will be further described below in combination with specific examples, but the present invention is not limited to these specific embodiments. Those skilled in the art will recognize that the invention covers all alternatives, modifications, and equivalents that may fall within the scope of the claims.

(Example 1)
This example provides a method for producing hexafluoro-1,3-butadiene, and the production method includes an intermediate production step and a hexafluoro-1,3-butadiene production step, specifically as follows. It is as follows.
A1. Production of 1,4-dibromo-2,3-dichloro-1,1,2,3,4,4-hexafluorobutane In a 500 mL Hastelloy pressure-resistant reaction pot, add 150 g of acetonitrile and 1,2-dibromo-1 -Chloro-1,2,2-trifluoroethane 69.1 g (0.25 mol), dibenzoyl peroxide 1.8 g (7.5 mmol) were added, purged with high purity _N2 for 10 minutes, and 34.8 g ( 0.30 mol) of chlorotrifluoroethylene was poured into the reaction vessel from the cylinder, and the temperature was raised to 80°C under mechanical stirring (300 to 500 r/min), and the pressure of the reaction vessel was increased to approximately 0.5 MPa for 12 hours. The reaction was completed by keeping warm.
When the reaction solution was analyzed by GC-MS and calculated, the conversion rate of the raw material 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 98.75%, and the conversion rate of the intermediate was 98.75%. The selectivity for one 1,4-dibromo-2,3-dichloro-1,1,2,3,4,4-hexafluorobutane was found to be 59.09%. The results are shown in Table 1.
The reaction solution was rectified under reduced pressure to obtain a highly pure intermediate A.
A2. Production of hexafluoro-1,3-butadiene 150 g of isopropanol, 2.0 g of elemental iodine, and 130 g (2.0 mol) of zinc powder were added to a 500 mL three-necked flask equipped with a magnetic stirrer, thermometer, condenser, and dropping funnel. . The top of the condenser was connected to the product collection bottle via a gas passage and the product collection tank was placed in a cryogenic cold trap (liquid nitrogen cooling). The temperature of the reaction bottle was raised to 70°C, and 275 g of 1,4-dibromo-2,3-dichloro-1,1,2,3,4,4-hexafluorobutane (purity 96%, 0.7 mol) was added under magnetic stirring. ) was added dropwise and the product was collected, and the addition was completed in about 1 h. After the dropwise addition was completed, the temperature was raised to 80°C and kept at this temperature for 3 hours to complete the reaction. The product collected in the cold trap was found to be hexafluoro-1,3-butadiene by GC-MS and nuclear magnetic properties, and 97.0 g of the product was collected and obtained, with a purity of 96.6%. The rate was 86.0%. The results are shown in Table 3.

(Example 2)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
In the intermediate production process, the type of initiator was changed, and 1.1 g (7.5 mmol) of di-tert-butyl peroxide was used instead of dibenzoyl peroxide in Example 1. The reaction results are shown in Table 1.
In the process of producing hexafluoro-1,3-butadiene, the type of catalyst was changed and 2.5 g of zinc iodide was used in place of the simple iodine of Example 1, yielding 89.20 g of a product. The results are shown in Table 3.

(Example 3)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
In the intermediate production process, the type of initiator was changed, and 0.68 g (7.5 mmol) of tert-butyl hydroperoxide was used instead of dibenzoyl peroxide in Example 1. The reaction results are shown in Table 1.
In the process of producing hexafluoro-1,3-butadiene, the type of catalyst was changed, and 1.5 g of 1,2-dibromoethane was used in place of the simple iodine of Example 1, yielding 95.0 g of the product. The results are shown in Table 3.

(Example 4)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
In the intermediate production process, the reaction temperature was lowered from 80°C to 60°C, and the reaction results are shown in Table 1.
In the process of producing hexafluoro-1,3-butadiene, the reaction temperature was lowered from 70°C to 60°C to obtain 76.20g of product. The results are shown in Table 3.

(Example 5)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
In the intermediate production process, the reaction temperature was raised from 80°C to 100°C. The reaction results are shown in Table 1.
In the process of producing hexafluoro-1,3-butadiene, the reaction temperature was raised from 70°C to 90°C to obtain 101.3g of product. The results are shown in Table 3.

(Example 6)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
In the intermediate production process, the type of solvent was changed, and 150 g of diethylene glycol dimethyl ether was used instead of acetonitrile in Example 1. The reaction results are shown in Table 1.
In the hexafluoro-1,3-butadiene manufacturing process, the type of solvent was changed and 150 g of N,N-dimethylacetamide was used in place of the isopropanol in Example 1, yielding 80.50 g of the product. The results are shown in Table 3.

(Example 7)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
In the intermediate manufacturing process, the blending ratio of the materials was changed, and the amount of chlorotrifluoroethylene used was changed from the original 34.8 g (0.30 mol) to 58.0 g (0.50 mol). The reaction results are shown in Table 1.
In the hexafluoro-1,3-butadiene manufacturing process, the blending ratio of materials was changed, and the amount of zinc powder used was changed from the original 130 g (2.0 mol) to 91.0 g (1.4 mol). 68.4 g of product was obtained. The results are shown in Table 3.

(Example 8)
This example provides a method for producing hexafluoro-1,3-butadiene, and the production method includes an intermediate production step and a hexafluoro-1,3-butadiene production step, specifically: It is as follows.
A1. Production of 1,2,4-tribromo-3-chloro-1,1,2,3,4,4-hexafluorobutane 150 g of acetonitrile, 1,2-dibromo-1 in a 500 mL pressure-resistant reaction pot made of Hastelloy material. -Chloro-1,2,2-trifluoroethane 69.1 g (0.25 mol), di-tert-butyl peroxide 1.1 g (7.5 mmol) were added, purged with high purity _N2 for 10 minutes, and 48 .3 g (0.30 mol) of trifluorobromoethylene was poured into the reaction vessel from the cylinder, and the temperature was raised to 100 ° C. under mechanical stirring (300 to 500 r/min), and the pressure of the reaction vessel was increased to about 0.6 MPa. The mixture was kept warm for 12 hours to complete the reaction.
When the reaction solution was analyzed by GC-MS and calculated, the conversion rate of the raw material 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 97.6%, and the conversion rate of the intermediate 1,2-dibromo-1-chloro-1,2,2-trifluoroethane was 97.6%. The selectivity for 1,2,4-tribromo-3-chloro-1,1,2,3,4,4-hexafluorobutane was found to be 73.9%. The results are shown in Table 2.
The reaction solution was rectified under reduced pressure to obtain a highly pure intermediate A.
A2. Production of hexafluoro-1,3-butadiene 150 g of acetic acid, 2.0 g of elemental iodine, and 130 g (2.0 mol) of zinc powder were added to a 500 mL three-necked flask equipped with a magnetic stirrer, thermometer, condenser, and dropping funnel. . The top of the condenser was connected to the product collection bottle via a gas passage and the product collection tank was placed in a cryogenic cold trap (liquid nitrogen cooling). The temperature of the reaction bottle was raised to 60°C, and 312.3 g of 1,2,4-tribromo-3-chloro-1,1,2,3,4,4-hexafluorobutane (purity 98%, 0 .7 mol) was added dropwise and the product was collected, and the addition was completed in about 2 h. After the dropwise addition was completed, the temperature was raised to 80°C and kept at this temperature for 3 hours to complete the reaction. The product collected in the cold trap was found to be hexafluoro-1,3-butadiene by GC-MS and nuclear magnetic properties, and 78.20 g of the product was collected and obtained, with a purity of 97.5%. The rate was 69.9%. The results are shown in Table 3.

(Example 9)
The operation of this embodiment is the same as that of embodiment 8, and differs only in the following points.
In the intermediate production process, the type of solvent was changed, and 150 g of diethylene glycol dimethyl ether was used instead of acetonitrile in Example 7. The reaction results are shown in Table 2.
In the hexafluoro-1,3-butadiene manufacturing process, the type of solvent was changed and 150 g of N,N-dimethylacetamide was used in place of acetic acid in Example 7, yielding 82.50 g of the product. The results are shown in Table 3.

(Example 10)
The operation of this embodiment is the same as that of embodiment 8, and differs only in the following points.
In the intermediate production process, the reaction temperature was raised from 100°C to 160°C. The reaction results are shown in Table 2.
In the process of producing hexafluoro-1,3-butadiene, the type of catalyst was changed and 2.5 g of zinc iodide was used instead of the simple iodine of Example 7, yielding 72.2 g of the product. The results are shown in Table 3.

(Example 11)
The operation of this embodiment is the same as that of embodiment 8, and differs only in the following points.
In the intermediate manufacturing process, the blending ratio of the materials was changed, and the amount of trifluorobromoethylene used was changed from the original 48.3 g (0.30 mol) to 40.3 g (0.25 mol). The reaction results are shown in Table 2.
In the hexafluoro-1,3-butadiene production process, the amount of catalyst iodine used was increased from the original 2.0 g to 4.0 g, yielding 74.5 g of product. The results are shown in Table 3.

(Comparative example 1)
The operation of this embodiment is the same as that of embodiment 1, and differs only in the following points.
No initiator dibenzoyl peroxide was added during the intermediate production process. The reaction results are shown in Table 1.
In the process of producing hexafluoro-1,3-butadiene, 78.50 g of product was obtained without adding iodine as a catalyst. The results are shown in Table 3.

(Comparative example 2)
Add 276.3 g (1.0 mol) of 1,2-dibromo-1-chloro-1,2,2-trifluoroethane to a glass photoreactor equipped with a jacket cold trap, and insert a 400 W ultraviolet high-pressure mercury lamp. did. Turn on the low temperature cycle (0 °C), turn on the high pressure mercury lamp, and slowly flow in chlorotrifluoroethylene (50 mL/min), a total of 139.2 g (1.2 mol), and finish flowing for about 10 hours. Ta. After the inflow was completed, the high-pressure mercury lamp and low temperature cycle were turned off, and the reaction solution was analyzed by GC-MS and calculated. The conversion rate of fluoroethane was 54.5%, and the selectivity of the intermediate 1,4-dibromo-2,3-dichloro-1,1,2,3,4,4-hexafluorobutane was 38. It was found to be 2%. The results are shown in Table 1.

Claims (10)

A method for producing hexafluoro-1,3-butadiene, comprising:
A1. 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and trifluorohaloethylene are reacted in a polar aprotic solvent under the action of an initiator, and the reaction solution is purified to obtain 1 ,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane, wherein the structural formula of the trifluorohaloethylene is CF ₂ =CFX. , where X is Cl, Br or I,
The initiator is at least one selected from azobisisobutyronitrile, di-tert-butyl peroxide, dibenzoyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, potassium persulfate, and ammonium persulfate;
A2. Dehalogenation reaction of 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane and zinc powder to produce hexafluoro-1,3-butadiene and a step of obtaining the
A method for producing hexafluoro-1,3-butadiene, characterized by: The molar blending ratio of the 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and the initiator is 1:0.01 to 1:0.1.
The method for producing hexafluoro-1,3-butadiene according to claim 1, characterized in that: The A1 step is performed in an inert gas atmosphere, and the inert gas is at least one selected from nitrogen, helium, and argon.
The method for producing hexafluoro-1,3-butadiene according to claim 1, characterized in that: The polar aprotic solvent is at least one selected from tetrahydrofuran, 1,4-dioxane, acetonitrile, diethylene glycol dimethyl ether, N,N-dimethylformamide, and N,N-dimethylacetamide.
4. The method for producing hexafluoro-1,3-butadiene according to claim 3. The A2 step is performed in the presence of a catalyst, and the catalyst is at least one selected from zinc bromide, zinc iodide, and simple iodine.
The method for producing hexafluoro-1,3-butadiene according to claim 1, characterized in that: The molar blending ratio of the 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane and the catalyst is 1:0.01 to 1:0.1. is,
6. The method for producing hexafluoro-1,3-butadiene according to claim 5. The A2 step is a reaction in an organic solvent, and the organic solvent is formic acid, acetic acid, trifluoroacetic acid, propionic acid, dichloromethane, chloroform, carbon tetrachloride, dichloroethane, 1,1,1-trichloroethane, isopropanol, tert-butanol. , N,N-dimethylformamide, N,N-dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone or hexamethylphosphamide,
The method for producing hexafluoro-1,3-butadiene according to claim 1, characterized in that: The reaction temperature of the A1 step is 60°C to 200°C, and the reaction is kept at a temperature of 1 to 12 hours, and the reaction temperature of the A2 step is 40°C to 150°C, and the reaction is kept at a temperature of 1 to 24 hours.
The method for producing hexafluoro-1,3-butadiene according to claim 1, characterized in that: The reaction temperature of the A1 step is 80° C. to 160° C., and the reaction is kept at a temperature of 6 to 12 hours. The reaction temperature of the A2 step is 60° C. to 90° C., and the reaction is kept at a temperature of 3 to 6 hours.
9. The method for producing hexafluoro-1,3-butadiene according to claim 8. A method for producing 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane, comprising:
In a polar aprotic solvent, 1,2-dibromo-1-chloro-1,2,2-trifluoroethane and trifluorohaloethylene are reacted in an inert gas atmosphere under the action of an initiator. a step of rectifying and purifying the liquid to obtain 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane, the step of obtaining 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane; The formula is CF ₂ =CFX, where X is Cl, Br or I;
The initiator is at least one selected from azobisisobutyronitrile, di-tert-butyl peroxide, dibenzoyl peroxide, dicumyl peroxide, tert-butyl hydroperoxide, potassium persulfate, and ammonium persulfate. ,
A method for producing 1,4-dibromo-2-chloro-3-halo-1,1,2,3,4,4-hexafluorobutane.