Method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane through electrolytic fluorination of hexafluoropropylene tripolymer

Abstract

The invention discloses a method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane through electrolytic fluorination of a hexafluoropropylene tripolymer, and relates to the field of organic fluorine chemistry. According to the method, anhydrous hydrogen fluoride is adopted as a solvent and a fluorine source, electrolytic fluorination is carried out in a nickel or monel alloy electrolytic bath, the fluorination selectivity is improved by optimizing the current density, the voltage, the temperature and the reaction time, generation of by-products is reduced, and a target product is purified through rectification. The method is stable in process, high in controllability and suitable for industrial production.

Description

Technical Field

[0001] The invention relates to the field of organic fluorine chemistry, in particular to a method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer. Background Art

[0002] Perfluorinated compounds (PFCs) are widely used in the fields of electronic chemistry, aerospace, semiconductor manufacturing, lubricants, medicine and high-end fluorine materials due to their unique chemical stability, high temperature resistance, low surface energy and excellent dielectric properties. Among them, perfluoroalkanes are a typical class of perfluorinated compounds. All hydrogen atoms in their molecules are replaced by fluorine atoms, showing extremely low reactivity, high volatility and chemical inertness. Therefore, this type of compound is often used to manufacture corrosion-resistant solvents, coolants, fluorine lubricants and special dielectric fluids.

[0003] Hexafluoropropylene trimer (C9F 18 ) is an important perfluoroolefin trimer, which is polymerized by three molecules of hexafluoropropylene (C3F6) under specific catalytic conditions and mainly consists of three isomers (T-1, T-2, T-3). This compound has important application value in the synthesis of fluorine fine chemicals due to its unique structure and chemical stability. In recent years, the use of hexafluoropropylene trimer as a raw material to prepare more complex perfluoroalkane derivatives through selective fluorination or structural rearrangement has become a research hotspot. For example, the target product 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane (C 12 F 24 ) is a perfluoroalkyl compound with high stability, low surface tension and excellent insulation properties. It can be used in special coolants, fluorine solvents, high-end electronic chemicals and medical fluorine carrier materials.

[0004] Electrolytic fluorination is a relatively mature industrial fluorination method. This process uses anhydrous hydrogen fluoride (HF) as a fluorine source to gradually replace hydrogen in organic molecules with fluorine under electrolytic conditions. This method is developed from the Simons fluorination process and is widely used in the preparation of perfluoroalkanes, perfluorocycloalkanes and other high-end fluorine fine chemicals. For example, perfluorobutane, perfluorohexane, perfluorooctane, etc. can all be prepared by this method.

[0005] However, electrolytic fluorination also has the following technical challenges: the selectivity of the target product is difficult to control and is easily accompanied by the generation of by-products; hydrogen fluoride is highly corrosive to equipment during the reaction; and the reaction conditions need to be precisely controlled to avoid excessive fluorination or degradation of the carbon skeleton. Summary of the invention

[0006] In order to solve these problems, the present invention provides an efficient and controllable electrolytic fluorination process, realizes the directional fluorination of hexafluoropropylene trimer, and successfully prepares 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane. Compared with the traditional direct fluorination method and high-temperature gas phase fluorination method, the electrolytic fluorination process of the present invention has better selectivity, lower energy consumption and milder reaction conditions, provides a new technical path for the fine synthesis of perfluoroalkanes, and has broad industrial application prospects.

[0007] The specific plan is as follows:

[0008] A method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer, characterized in that it comprises the following steps:

[0009] (1) preparing an electrolyte: adding 100 to 500 parts by weight of anhydrous hydrogen fluoride and 0.5 to 5 parts by weight of a conductive salt into an electrolytic cell, and stirring the mixture evenly;

[0010] (2) Adding raw materials: under stirring conditions, add 50 to 300 parts by weight of hexafluoropropylene trimer to the electrolytic cell to make it uniformly dissolved in HF, and then add 2.5 to 6 parts of catalyst;

[0011] (3) Electrolysis reaction: The electrolysis reaction should be carried out in a closed system, with controlled current density and voltage, and the electrolysis should be carried out at -10 to 5°C for 5 to 24 hours;

[0012] (4) Reaction termination and separation: After the reaction is completed, the reaction mixture is distilled to recover HF, and the remaining liquid is washed with water and neutralized; the target product is purified by vacuum distillation to obtain 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane;

[0013] The catalyst is prepared by combining a complexing active agent with ammonia water to obtain a catalyst precursor, which is loaded into a reactor for fluorination;

[0014] The complexing active agent is prepared by reacting allyl polyethylene glycol, (ferrocenyl) hexanethiol, trans-2-butene-1,4-dicarboxylic acid and dimethylpropylene S-thiodiphosphoric acid.

[0015] In one or more embodiments, the conductive salt is selected from one or a combination of potassium fluoride (KF), cesium fluoride (CsF) or potassium tetrafluoroborate (KBF4).

[0016] In one or more embodiments, the moisture content in the closed electrolysis reaction system is no higher than 50 ppm.

[0017] In one or more embodiments, the anode of the electrolysis reaction is made of at least one of nickel, nickel-copper alloy, and platinum metal, and the cathode is made of graphite, nickel, or stainless steel.

[0018] In one or more embodiments, the electrolysis current density is controlled at 1 to 5 A / dm 2 , the voltage is controlled at 4~6V.

[0019] In one or more embodiments, the distillation pressure is controlled at 5-50 kPa, and the number of distillation plates is 10-50.

[0020] In one or more embodiments, the preparation method of the catalyst is:

[0021] S1. Preparation of mixed solution: add 29-58 parts of Co(NO3)2, 10-20 parts of Zn(NO3)2, 4-8 parts of La(NO3)3 to 300-500 parts of water by weight, then add complexing agent, stir, add 20-50 parts of 20-30% ammonia water dropwise to the reactor, react at 50-70°C for 100-150 minutes, age after forming gel, spray dry, and then calcine at 400-600°C to obtain a catalyst precursor;

[0022] S2. Preparation of catalyst: The catalyst precursor obtained in S1 is loaded into a reactor, and a mixed gas of nitrogen and HF with a volume of 5-10 times, and a mixed gas volume ratio of 1:0.2-0.5 is introduced for fluorination. After the ventilation is completed, the gas is replaced with nitrogen to obtain a catalyst.

[0023] In one or more embodiments, the preparation method of the complexing active agent is:

[0024] According to weight, 150-200 parts of allyl polyethylene glycol, 0.03-0.5 parts of (ferrocenyl) hexanethiol, 10-20 parts of trans-2-butene-1,4-dicarboxylic acid, 3-8 parts of dimethylpropylene S-thiodiphosphoric acid (CAS: 684271-20-3), and 0.3-3 parts of benzoyl peroxide are stirred at 50-60° C. for reaction for 120-150 minutes to obtain a complexing active agent.

[0025] The catalyst has the following beneficial effects:

[0026] 1. Increase the number and accessibility of catalyst active centers

[0027] Introduction of ferrocenyl groups: By introducing electrochemically active ferrocenyl groups into the polyethylene glycol chain, the electron transfer capacity of the catalyst is increased. This modification not only improves the conductivity of the catalyst, but also enhances its stability, thereby providing more active sites in the catalytic process.

[0028] Increase the accessibility of active centers: Through chemical reactions and calcination processes, pure oxides (such as cobalt oxide, zinc oxide, and lanthanum oxide) are left. After fluorination, this process significantly increases the accessibility of active centers on the catalyst surface, making it easier for reactants to contact the active centers and accelerating the reaction rate.

[0029] 2. Optimize pore structure

[0030] Controlling pore size distribution: The pore structure of the oxide, including pore size and distribution, can be precisely controlled. This control helps achieve a higher specific surface area and more appropriate porosity, thereby improving the physical adsorption capacity and reaction selectivity of the catalyst.

[0031] Forming a porous structure: The porous structure formed through the above process not only increases the surface area of ​​the catalyst, but also provides more reaction sites, which is beneficial to the diffusion and adsorption of reactants, further improving the catalytic efficiency.

[0032] 3. Improve catalytic performance

[0033] Enhanced catalytic activity: Due to the increase in the number of active centers and the optimization of the pore structure, the catalytic activity of the catalyst has been significantly improved. This means that under the same reaction conditions, the catalyst can promote the conversion of reactants into products more quickly, increasing the reaction rate and yield; by introducing ferrocenyl groups to the polyethylene glycol chain, and copolymerizing trans-2-butene-1,4-dicarboxylic acid with dimethylpropylene S-thiodiphosphoric acid to generate polymers containing carboxylic acid and phosphoric acid groups, these steps significantly improved the pore structure control morphology of the catalyst, increased the number and accessibility of the catalyst's active centers, optimized the pore structure, and ultimately improved the catalytic performance.

[0034] Technical Effects

[0035] The present invention optimizes the electrolytic fluorination process to achieve the hexafluoropropylene trimer (C9F 18 ) to 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane (C 12 F 24 ) has the following technical effects:

[0036] 1. Improve the selectivity of target products and reduce the generation of by-products;

[0037] 2. Control the fluorination process and improve the purity of the target product;

[0038] 3. Reduce raw material loss and improve reactant utilization. DETAILED DESCRIPTION

[0039] The present invention is further described below in conjunction with specific embodiments, but the present invention is not limited to these specific embodiments. Those skilled in the art should recognize that the present invention covers all possible alternatives, improvements and equivalents within the scope of the claims.

[0040] The test method involved in the present invention is as follows:

[0041] 1) Purity of target product: Gas chromatography-mass spectrometry (GC-MS) analysis was used to determine the purity of the target product.

[0042] 2) Target product yield: The target product yield is calculated according to the following formula: Yield (%) = target product mass / theoretical product mass * 100%

[0043] Example 1

[0044] (1) Preparation of electrolyte

[0045] Add 300 g of anhydrous hydrogen fluoride (HF) into the electrolytic cell, and then add 2 g of potassium fluoride (KF) as a conductive salt, stir evenly, and allow it to fully dissolve.

[0046] (2) Add raw materials

[0047] Under stirring conditions, hexafluoropropylene trimer (C9F 18 )150g, stirred to make it uniformly dissolved in HF, and then added 2.5g catalyst.

[0048] The preparation method of the catalyst:

[0049] S1, preparation of mixed solution: add 29g Co(NO3)2, 10g Zn(NO3)2, 4g La(NO3)3 to 300g water, then add complexing active agent, stir, add 20g 20% ​​ammonia water dropwise to the reactor, react at 50°C for 100 minutes, age after forming gel, spray dry, and then calcine at 400°C to obtain a catalyst precursor;

[0050] S2. Preparation of catalyst: The catalyst precursor obtained in S1 is loaded into a reactor, and a mixed gas of nitrogen and HF with a volume ratio of 1:0.2 with 5 times the volume is introduced for fluorination. After the ventilation is completed, the gas is replaced with nitrogen to obtain a chemical catalyst.

[0051] The preparation method of the complexing active agent is:

[0052] 150g of allyl polyethylene glycol, 0.03g of (ferrocenyl) hexanethiol, 10g of trans-2-butene-1,4-dicarboxylic acid, 3g of dimethylpropylene S-thiodiphosphoric acid, CAS: 684271-20-3, and 0.3g of benzoyl peroxide were stirred at 50°C for reaction for 120 minutes to obtain a complexing active agent.

[0053] (3) Electrolysis reaction

[0054] The electrolytic cell temperature was controlled at -5°C and the current density was 2A / dm 2 The electrolysis was carried out at a voltage of 5 V for 16 hours. The electrolytic cell used a nickel anode and a graphite cathode, and the water content in the system was kept at no more than 30 ppm.

[0055] (4) Reaction termination and separation

[0056] After the electrolysis reaction is completed, HF is recovered by vacuum distillation, and then the residual liquid is washed with water and neutralized. The product is sent to a distillation tower for purification, with a distillation pressure of 10 kPa and 30 plates, and finally 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane with a purity of 98.7% is obtained.

[0057] After analysis and testing, the purity of the target product in this example is 99.33%, and the yield of the target product is 87.50%.

[0058] Example 2

[0059] (1) Preparation of electrolyte

[0060] Add 200 g of anhydrous hydrogen fluoride (HF) into the electrolytic cell, and then add 3 g of cesium fluoride (CsF) as a conductive salt, and stir evenly.

[0061] (2) Add raw materials

[0062] Hexafluoropropylene trimer (C9F 18 )100g, stirred to dissolve, and then added 3.5g catalyst.

[0063] The preparation method of the catalyst:

[0064] S1, preparation of mixed solution: add 34g Co(NO3)2, 13.5g Zn(NO3)2, 6g La(NO3)3 to 400g water, then add complexing active agent, stir, add 30g 25% ammonia water dropwise to the reactor, react at 60°C for 125 minutes, age after forming gel, spray dry, and then calcine at 500°C to obtain catalyst precursor;

[0065] S2. Preparation of catalyst: The catalyst precursor obtained in S1 is loaded into a reactor, and a mixed gas of nitrogen and HF with a volume ratio of 7.5 times the volume thereof is introduced, with the mixed gas volume ratio of 1:0.3, for fluorination. After the ventilation is completed, the mixture is replaced with nitrogen to obtain a catalyst.

[0066] The preparation method of the complexing active agent is:

[0067] 165g of allyl polyethylene glycol, 0.2g of (ferrocenyl) hexanethiol, 15g of trans-2-butene-1,4-dicarboxylic acid, 5g of dimethylpropylene S-thiodiphosphoric acid, CAS: 684271-20-3, and 1g of benzoyl peroxide were stirred at 55°C for reaction for 130 minutes to obtain a complexing active agent.

[0068] (3) Electrolysis reaction

[0069] At 0℃, the current density is controlled at 3A / dm 2 , voltage 4.5V, electrolysis reaction time 12 hours. The electrolytic cell uses nickel-copper alloy anode and nickel cathode, and the water content in the system is ≤40ppm.

[0070] (4) Reaction termination and separation

[0071] After the electrolysis is completed, HF is recovered, and the remaining liquid is washed with water and neutralized. The target product is purified by vacuum distillation, with a distillation pressure of 20 kPa and 40 plates, and finally 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane with a purity of 98.5% is obtained.

[0072] After analysis and testing, the purity of the target product in this example is 99.40%, and the yield of the target product is 87.72%.

[0073] Example 3

[0074] (1) Preparation of electrolyte

[0075] Add 400 g of anhydrous hydrogen fluoride (HF) and 1 g of potassium tetrafluoroborate (KBF4) as a conductive salt into the electrolytic cell and stir evenly.

[0076] (2) Add raw materials

[0077] Hexafluoropropylene trimer (C9F 18 )250g, after dissolving, add 5g catalyst.

[0078] The preparation method of the catalyst:

[0079] S1, preparation of mixed solution: add 46g Co(NO3)2, 17g Zn(NO3)2, 6g La(NO3)3 to 400g water, then add complexing agent, stir, add 40g 25% ammonia water dropwise to the reactor, react at 60°C for 125 minutes, age after forming gel, spray dry, and then calcine at 500°C to obtain catalyst precursor;

[0080] S2. Preparation of catalyst: The catalyst precursor obtained in S1 is loaded into a reactor, and a mixed gas of nitrogen and HF with a volume ratio of 7.5 times the volume thereof is introduced, with the mixed gas volume ratio of 1:0.4, for fluorination. After the ventilation is completed, the mixture is replaced with nitrogen to obtain a catalyst.

[0081] The preparation method of the complexing active agent is:

[0082] 180g of allyl polyethylene glycol, 0.4g of (ferrocenyl) hexanethiol, 18g of trans-2-butene-1,4-dicarboxylic acid, 7g of dimethylpropylene S-thiodiphosphoric acid, CAS: 684271-20-3, and 2g of benzoyl peroxide were stirred at 55°C for 140 minutes to obtain a complexing active agent.

[0083] (3) Electrolysis reaction

[0084] At -10℃, the current density is controlled at 1.5A / dm 2 , voltage 4.8V, electrolysis reaction time 24 hours. The electrolytic cell uses platinum anode and nickel cathode, and the water content in the system does not exceed 50ppm.

[0085] (4) Reaction termination and separation

[0086] After the electrolysis, HF was recovered by distillation, and the residual liquid was washed with water and neutralized. The target product was distilled (distillation pressure 5 kPa, 50 plates), and finally 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane with a purity of 99.0% was obtained.

[0087] After analysis and testing, the purity of the target product in this example is 99.44%, and the yield of the target product is 87.74%.

[0088] Example 4

[0089] (1) Preparation of electrolyte

[0090] Add 250 g of anhydrous hydrogen fluoride (HF) into the electrolytic cell, add 2 g each of cesium fluoride (CsF) and potassium tetrafluoroborate (KBF4) as conductive salts, and stir evenly.

[0091] (2) Add raw materials

[0092] Hexafluoropropylene trimer (C9F18 )200g, stir evenly, and then add 6g catalyst.

[0093] The preparation method of the catalyst:

[0094] S1, preparation of mixed solution: add 58g Co(NO3)2, 20g Zn(NO3)2, 8g La(NO3)3 to 500g water, then add complexing active agent, stir, add 50g 30% ammonia water dropwise to the reactor, react at 70°C for 150 minutes, age after forming gel, spray dry, and then calcine at 600°C to obtain a catalyst precursor;

[0095] S2. Preparation of catalyst: The catalyst precursor obtained in S1 is loaded into a reactor, and a mixed gas of nitrogen and HF with a volume ratio of 10 times is introduced into the reactor, with the mixed gas volume ratio of 1:0.5, for fluorination. After the ventilation is completed, the gas is replaced with nitrogen to obtain a catalyst.

[0096] The preparation method of the complexing active agent is:

[0097] 200 g of allyl polyethylene glycol, 0.5 g of (ferrocenyl) hexanethiol, 20 g of trans-2-butene-1,4-dicarboxylic acid, 8 g of dimethylpropylene S-thiodiphosphoric acid, CAS: 684271-20-3, and 3 g of benzoyl peroxide were stirred at 60° C. for reaction for 150 minutes to obtain a complexing active agent.

[0098] (3) Electrolysis reaction

[0099] At 5°C, the current density was controlled at 4A / dm 2 , voltage 5.5V, electrolysis reaction time 8 hours. The electrolytic cell uses nickel anode and stainless steel cathode, and the water content in the system does not exceed 25ppm.

[0100] (4) Reaction termination and separation

[0101] After the electrolysis is completed, HF is recovered by distillation, and the remaining liquid is washed with water and neutralized. The target product is purified by vacuum distillation at a distillation pressure of 30 kPa and 20 plates, and finally 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane with a purity of 98.3% is obtained.

[0102] After analysis and testing, the purity of the target product in this example is 99.49%, and the yield of the target product is 87.80%.

[0103] Comparative Example 1

[0104] In this example, no complexing activator is added during the catalyst preparation process, and the rest is the same as in Example 1.

[0105] After analysis and testing, the purity of the target product in this example is 99.05%, and the yield of the target product is 84.85%.

[0106] Comparative Example 2

[0107] In this example, no dimethylpropylene S-thiodiphosphoric acid was added during the preparation of the complexing active agent, and the rest was the same as in Example 1.

[0108] After analysis and testing, the purity of the target product in this example is 99.21%, and the yield of the target product is 86.65%.

[0109] Compared with the comparative example, the present invention shows certain advantages in terms of target product purity and product yield, which proves the superiority of the present method.

[0110] Although the specific embodiments of the present invention have been described in detail, those skilled in the art may implement modifications of the described embodiments. In addition, such modifications may be obtained without departing from the true spirit and scope of the present invention as described in the appended claims.

Claims

1. A method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer, characterized in that: The following steps are involved: (1) preparing an electrolyte: adding 100 to 500 parts by weight of anhydrous hydrogen fluoride and 0.5 to 5 parts by weight of a conductive salt into an electrolytic cell, and stirring the mixture evenly; (2) Adding raw materials: under stirring conditions, add 50 to 300 parts by weight of hexafluoropropylene trimer to the electrolytic cell to make it uniformly dissolved in HF, and then add 2.5 to 6 parts of catalyst; (3) Electrolysis reaction: The electrolysis reaction should be carried out in a closed system, with controlled current density and voltage, and the electrolysis should be carried out at -10 to 5°C for 5 to 24 hours; (4) Reaction termination and separation: After the reaction is completed, the reaction mixture is distilled to recover HF, and the remaining liquid is washed with water and neutralized; the target product is purified by vacuum distillation to obtain 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane; The catalyst is prepared by combining a complexing active agent with ammonia water to obtain a catalyst precursor, which is loaded into a reactor for fluorination; The complexing active agent is prepared by reacting allyl polyethylene glycol, (ferrocenyl) hexanethiol, trans-2-butene-1,4-dicarboxylic acid and dimethylpropylene S-thiodiphosphoric acid.

2. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 1, characterized in that: The conductive salt is selected from potassium fluoride (KF), cesium fluoride (CsF) or potassium tetrafluoroborate (KBF4) or a combination thereof.

3. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 1, characterized in that: The water content in the electrolysis reaction closed system is not higher than 50 ppm.

4. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 1, characterized in that: The electrolytic reaction anode is made of at least one of nickel, nickel-copper alloy and platinum metal, and the cathode is made of graphite, nickel or stainless steel.

5. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 1, characterized in that: The current density is controlled at 1-5A / dm 2 , the voltage is controlled at 4~6V.

6. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 1, characterized in that: The distillation pressure is controlled at 5-50 kPa, and the number of distillation plates is 10-50.

7. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 1, characterized in that: The preparation method of the catalyst: S1. Preparation of mixed solution: add 29-58 parts of Co(NO3)2, 10-20 parts of Zn(NO3)2, 4-8 parts of La(NO3)3 to 300-500 parts of water by weight, then add complexing agent, stir, add 20-50 parts of 20-30% ammonia water dropwise to the reactor, react at 50-70°C for 100-150 minutes, age after forming gel, spray dry, and then calcine at 400-600°C to obtain a catalyst precursor; S2. Preparation of catalyst: The catalyst precursor obtained in S1 is loaded into a reactor, and a mixed gas of nitrogen and HF with a volume of 5-10 times, and a mixed gas volume ratio of 1:0.2-0.5 is introduced for fluorination. After the ventilation is completed, the gas is replaced with nitrogen to obtain a catalyst.

8. The method for preparing 3-pentafluoroethyl-4-trifluoromethyl-dodecafluorohexane by electrolytic fluorination of hexafluoropropylene trimer according to claim 7, characterized in that: The preparation method of the complexing active agent is: According to weight, 150-200 parts of allyl polyethylene glycol, 0.03-0.5 parts of (ferrocenyl) hexanethiol, 10-20 parts of trans-2-butene-1,4-dicarboxylic acid, 3-8 parts of dimethylpropylene S-thiodiphosphoric acid, and 0.3-3 parts of benzoyl peroxide are stirred at 50-60° C. for reaction for 120-150 minutes to obtain a complexing active agent.