Preparation method of diisopropyl peroxydicarbonate and application of diisopropyl peroxydicarbonate

Abstract

The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of diisopropyl peroxydicarbonate and application of the diisopropyl peroxydicarbonate. The preparation method comprises the following steps: firstly, adding isopropyl chloroformate and an ester-soluble organic solution into a three-necked flask, starting stirring, adding a hydrogen peroxide solution, slowly dropwise adding a sodium hydroxide solution into the three-necked flask when the temperature of a mixture in the flask is stabilized at-5 DEG C, controlling the time and temperature in the reaction process, finally separating out an organic phase, washing with water, and drying to obtain the isopropyl chloroformate. And drying with anhydrous sodium sulfate to obtain the product. According to the preparation method disclosed by the invention, by optimizing and precisely controlling the preparation process conditions, the preparation process is safe and controllable, the obtained diisopropyl peroxydicarbonate is high in yield and good in stability, can be directly used for preparing polyvinylidene fluoride, can be polymerized under a low-temperature condition without adding a chain transfer agent, improves the molecular chain regularity of polyvinylidene fluoride, has few abnormal structures, and is suitable for industrial production. The crystallinity is high, and the comprehensive performance is good.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and specifically relates to a preparation method of diisopropyl peroxydicarbonate and application of diisopropyl peroxydicarbonate. Background Art

[0002] Peroxydicarbonate is a commonly used initiator in free radical polymerization. It has a low decomposition temperature and can initiate polymerization reactions at relatively low temperatures. It is particularly sensitive to temperature, impact, and chemicals such as acids and alkalis. It is very easy to decompose and cause explosions. It usually needs to be diluted and stored at low temperatures.

[0003] Polyvinylidene fluoride (PVDF) is a fluorine-containing polymer with excellent performance. It has excellent chemical corrosion resistance, high temperature resistance, oxidation resistance, weather resistance, UV resistance, and radiation resistance, and has high mechanical strength, low surface energy, excellent processing performance, and special electrical properties such as piezoelectricity, thermoelectricity and ferroelectricity. Therefore, it is widely used in aerospace, high-performance membrane components, lithium batteries, automotive industry, electronics and electrical, biomedicine and other fields. However, in the molecular chain structure of polyvinylidene fluoride, there are abnormal structures of head-to-head and tail-to-tail connection. When the number of abnormal structures increases, the crystallinity of the polymer will be affected, defective parts will be generated inside the crystal, the swelling property to the solvent will be increased, and the melting point will be reduced. The proportion of this abnormal bonding structure depends on the polymerization conditions, especially the polymerization temperature. Therefore, it is necessary to develop a peroxydicarbonate initiator with good initiation activity at low temperature and can improve the regularity of the molecular chain of polyvinylidene fluoride. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention provides a preparation method of diisopropyl peroxydicarbonate and the application of diisopropyl peroxydicarbonate. The preparation method optimizes and precisely controls the preparation process conditions, and the preparation process is safe and controllable. The obtained diisopropyl peroxydicarbonate has a high yield and good stability, can be directly used in the preparation of polyvinylidene fluoride, does not need to add a chain transfer agent, can be polymerized under low temperature conditions, improves the regularity of the polyvinylidene fluoride molecular chain, has fewer abnormal structures, high crystallinity, and good comprehensive performance.

[0005] In order to achieve the above object, the present invention provides the following technical solutions: The first object of the present invention is to provide a method for preparing diisopropyl peroxydicarbonate, comprising the steps of: S1. Add isopropyl chloroformate and ester-soluble organic solution to a dried and cooled three-necked flask, turn on the stirrer, add hydrogen peroxide solution, and when the temperature of the mixture in the flask is stabilized at -5°C, add sodium hydroxide solution to the dropping funnel, and then slowly add it dropwise to the above three-necked flask, control the dropping time to 60-90min, and control the reaction temperature to be lower than 10°C during the reaction. After the sodium hydroxide solution is added dropwise, continue the reaction for 30-35min; S2. Pour the mixed solution after the reaction of S1 into a separatory funnel, separate the organic phase, wash it with water 2-3 times, and dry it with anhydrous sodium sulfate to obtain the product.

[0006] Isopropyl chloroformate is a toxic, colorless liquid with a pungent odor. It reacts with water or water vapor to release heat or form an explosive mixture, which is dangerous to use. The present invention strictly controls the order and conditions of adding raw materials, and first pre-treats a three-necked flask, and then dissolves isopropyl chloroformate in an ester-soluble organic solvent to reduce its concentration, which can greatly reduce its use risk. At the same time, hydrogen peroxide solution is first added at low temperature, and then pre-cooled sodium hydroxide is added in a titration manner. The diisopropyl peroxydicarbonate generated during the reaction is directly dissolved in the organic phase again, and its concentration is also reduced, reducing its potential risks such as decomposition and explosion. The sodium hydroxide is added in a titration manner, and the decomposition of diisopropyl peroxydicarbonate can also be reduced, and the final yield is improved. The end product is an organic phase solution that can be directly used to prepare polyvinylidene fluoride, and no storage is required, which can reduce the structural defects of polyvinylidene fluoride resin.

[0007] Furthermore, in the above technical solution, in S1, the molar ratio of isopropyl chloroformate, sodium hydroxide and hydrogen peroxide is 1:1.02-1.05:0.55-0.7.

[0008] Further, in the above technical solution S1, the ester-soluble organic solution is any one or more of ethyl acetate, diethyl malonate, and diethyl carbonate, and the added amount is 1-3 times the mass of isopropyl chloroformate. The ester-soluble organic solution is directly added before the reaction, which can reduce the risk of isopropyl chloroformate. At the same time, as a solvent for the final product, the generated product can also be directly diluted, reducing the decomposition and explosion risks of diisopropyl peroxydicarbonate, and having high stability.

[0009] Furthermore, in the above technical solution S1, before turning on the agitator, the temperature in the flask is first cooled to -5°C by an ice-salt bath. The pre-cooling treatment of the flask can place the raw material isopropyl chloroformate in a low temperature environment, improve its stability, and provide low temperature conditions for subsequent reactions.

[0010] Furthermore, in the above technical solution S1, the mass concentration of the hydrogen peroxide solution is 27%; the mass concentration of the sodium hydroxide solution is 32%.

[0011] Furthermore, in the above technical solution S1, the sodium hydroxide solution is cooled to 0° C. in an ice water bath in advance. Since the reaction process is an exothermic reaction, a large amount of heat will be released. In order to better control the temperature of the reaction solution, cooling the sodium hydroxide solution in advance can not only improve the reaction efficiency but also greatly reduce the risk of explosion.

[0012] Furthermore, in the above technical solution S2, the water used for washing is ice water. Specifically, ice water is water with a temperature below 5°C and not frozen. Using ice water to wash the product organic phase can not only remove water-soluble impurities, but also further reduce the product temperature to prevent its decomposition.

[0013] The second object of the present invention is to provide an application of diisopropyl peroxydicarbonate prepared by the above preparation method in the preparation of polyvinylidene fluoride, and the application method is: add deionized water to a closed polymerization kettle, evacuate the air in the kettle, and replace it with nitrogen until the oxygen content in the kettle is less than 10ppm, add methyl cellulose, control the temperature of the polymerization kettle to 10±2°C, add VDF (vinylidene fluoride) monomer at one time, add the above-prepared diisopropyl peroxydicarbonate solution, increase the pressure to 1-1.2MPa, start the polymerization reaction, control the temperature of the polymerization kettle to slowly rise to 20-35°C, react for 5-8h, stop the polymerization reaction when the pressure in the polymerization kettle is lower than 0.5Mpa, recover the remaining VDF monomer in the kettle, and obtain a powdered resin after centrifugation, washing and drying the polymer in the kettle. The present invention uses an organic phase to dissolve diisopropyl peroxydicarbonate in advance during the preparation process, thereby reducing its concentration and improving its stability. The obtained product has a high yield and a low risk of decomposition and explosion. The product can be directly used in the preparation of polyvinylidene fluoride as needed, has no storage risk, and has greatly reduced use risk. At the same time, no chain transfer agent needs to be added, so the product is more convenient to use. Furthermore, the product can react at a lower temperature, so the risk is low. The obtained polyvinylidene fluoride resin has fewer defect structures, good molecular chain regularity, high crystallinity, and excellent performance.

[0014] Furthermore, in the above technical solution, the amount of deionized water added is 1-2 times the weight of the VDF monomer; the amount of methyl cellulose added is 0.08-0.4‰ the weight of the VDF monomer.

[0015] Furthermore, in the above technical solution, the added amount of the diisopropyl peroxydicarbonate solution is 4.2-8.3‰ of the weight of the VDF monomer.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The invention strictly controls the adding sequence and conditions of the raw materials, precools the three-necked flask, and then dissolves isopropyl chloroformate in an ester-soluble organic solvent to reduce the concentration of isopropyl chloroformate, thereby greatly reducing the use risk of the isopropyl chloroformate. Meanwhile, a hydrogen peroxide solution is first added at a low temperature, and then precooled sodium hydroxide is added in a titration manner, so that the reaction speed can be controlled, and the generated diisopropyl peroxydicarbonate is directly dissolved in an organic phase for dilution, so that the potential risks of product decomposition, explosion and the like can be reduced. The sodium hydroxide is added in a titration manner, so that the decomposition of the diisopropyl peroxydicarbonate by the sodium hydroxide can be reduced, thereby improving the final yield.

[0017] The diisopropyl peroxydicarbonate prepared by the present invention is a solution dissolved in an organic phase, has good stability, and has a lower risk of decomposition and explosion. It can be directly used to prepare polyvinylidene fluoride, or can be prepared as needed without storage, which greatly reduces the storage risk. Moreover, no chain transfer agent needs to be added, and the reaction can be performed at a lower temperature. The obtained polyvinylidene fluoride resin has fewer structural defects, good molecular chain regularity, high crystallinity, excellent comprehensive performance, and good market competitiveness. DETAILED DESCRIPTION

[0018] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials involved in the following examples are common commercial products and can be purchased from the market unless otherwise specified.

[0019] The above-mentioned technical features of the present invention and the technical features specifically described below (such as implementation cases) can be combined with each other to form a new or preferred technical solution.

[0020] The raw materials involved in the embodiments of the present invention are either existing commercially available products or can be prepared according to existing methods, and the testing methods are industry methods.

[0021] Example 1 A method for preparing diisopropyl peroxydicarbonate comprises the following steps: S1. Add isopropyl chloroformate and ethyl acetate to a dried and cooled three-necked flask, cool the beaker to -5°C by a salt bath, turn on the agitator, add a 27% mass concentration of hydrogen peroxide solution, and when the temperature of the mixture in the bottle is stable at -5°C, add a 32% mass concentration of sodium hydroxide solution to the dropping funnel, and then slowly add it dropwise to the above three-necked flask, control the dropping time to 60 minutes, and control the reaction temperature to be lower than 10°C during the reaction. After the sodium hydroxide solution is added dropwise, continue the reaction for 35 minutes; wherein, the molar ratio of isopropyl chloroformate, sodium hydroxide, and hydrogen peroxide is 1:1.02:0.55; the amount of ethyl acetate used is twice the mass of isopropyl chloroformate.

[0022] S2. Pour the mixed solution after the reaction of S1 into a separatory funnel to separate the organic phase, wash it twice with ice water below 5°C, and dry it with anhydrous sodium sulfate to obtain an organic phase solution of diisopropyl peroxydicarbonate.

[0023] According to the iodine titration method for determination of organic peroxide content in GB / T 32102-2015, the mass ratio of diisopropyl peroxydicarbonate to ethyl acetate in the diisopropyl peroxydicarbonate organic phase solution was 29:71, and the yield of diisopropyl peroxydicarbonate was 98.0%.

[0024] Example 2 A method for preparing diisopropyl peroxydicarbonate comprises the following steps: S1. Add isopropyl chloroformate and diethyl carbonate to a dried and cooled three-necked flask, cool the beaker to -5°C by a salt bath, turn on the stirrer, add a 27% mass concentration of hydrogen peroxide solution, and when the temperature of the mixture in the bottle is stable at -5°C, add a 32% mass concentration of sodium hydroxide solution to the dropping funnel, and then slowly add it dropwise to the above three-necked flask, control the dropping time to 75min, and control the reaction temperature to be lower than 10°C during the reaction. After the sodium hydroxide solution is added dropwise, continue the reaction for 32min; wherein, the molar ratio of isopropyl chloroformate, sodium hydroxide, and hydrogen peroxide is 1:1.03:0.6; the amount of diethyl carbonate used is 3 times the mass of isopropyl chloroformate.

[0025] S2. Pour the mixed solution after the reaction of S1 into a separatory funnel to separate the organic phase, wash it three times with ice water below 5°C, and dry it with anhydrous sodium sulfate to obtain an organic phase solution of diisopropyl peroxydicarbonate.

[0026] According to the iodine titration method for determination of organic peroxide content in GB / T 32102-2015, the mass ratio of diisopropyl peroxydicarbonate to ethyl acetate in the diisopropyl peroxydicarbonate organic phase solution was 30:70, and the yield of diisopropyl peroxydicarbonate was 98.3%.

[0027] Example 3 A method for preparing diisopropyl peroxydicarbonate comprises the following steps: S1. Add isopropyl chloroformate and diethyl malonate to a dried and cooled three-necked flask, cool the beaker to -5°C by a salt bath, turn on the stirrer, add a 27% mass concentration of hydrogen peroxide solution, and when the temperature of the mixture in the bottle is stable at -5°C, add a 32% mass concentration of sodium hydroxide solution to the dropping funnel, and then slowly add it dropwise to the above three-necked flask, control the dropping time to 90 minutes, and control the reaction temperature to be lower than 10°C during the reaction. After the sodium hydroxide solution is added dropwise, continue the reaction for 30 minutes; wherein, the molar ratio of isopropyl chloroformate, sodium hydroxide, and hydrogen peroxide is 1:1.05:0.7; the amount of ethyl acetate used is 1 times the mass of isopropyl chloroformate.

[0028] S2. Pour the mixed solution after the reaction of S1 into a separatory funnel to separate the organic phase, wash it twice with ice water below 5°C, and dry it with anhydrous sodium sulfate to obtain an organic phase solution of diisopropyl peroxydicarbonate.

[0029] According to the iodine titration method for determination of organic peroxide content in GB / T 32102-2015, the mass ratio of diisopropyl peroxydicarbonate to ethyl acetate in the diisopropyl peroxydicarbonate organic phase solution was 44:56, and the yield of diisopropyl peroxydicarbonate was 97.2%.

[0030] Example 4 The preparation method of polyvinylidene fluoride comprises the following steps: 20 L of deionized water was added to a 40 L closed polymerization kettle, the air in the kettle was evacuated, and the oxygen content in the kettle was replaced by nitrogen until it was less than 10 ppm, 2 g of methyl cellulose was added, the temperature of the polymerization kettle was controlled at 10±2° C., 12 kg of VDF monomer was added at one time, 75 g of the organic phase solution of diisopropyl peroxydicarbonate prepared in Example 2 (containing 22.5 g of diisopropyl peroxydicarbonate and 52.5 g of ethyl acetate) was added, the pressure was increased to 1 MPa, the polymerization reaction was started, the temperature of the polymerization kettle was controlled to slowly rise to 20° C., the reaction was carried out for 8 h, when the pressure in the polymerization kettle was lower than 0.5 MPa, the polymerization reaction was stopped, the remaining VDF monomer in the kettle was recovered, the polymer in the kettle was centrifuged, washed, and dried to obtain 11.5 kg of polyvinylidene fluoride powdered resin, the yield of which was 95.8% after testing, and the defective structure of head-to-head and tail-to-tail connection in the structure was 4.3%.

[0031] Example 5 The preparation method of polyvinylidene fluoride comprises the following steps: 20 L of deionized water was added to a 40 L closed polymerization kettle, the air in the kettle was evacuated, and the oxygen content in the kettle was replaced by nitrogen until it was less than 10 ppm, 5 g of methyl cellulose was added, the temperature of the polymerization kettle was controlled at 10±2° C., 12 kg of VDF monomer was added at one time, 100 g of the diisopropyl peroxydicarbonate organic phase solution prepared in Example 2 (containing 30 g of diisopropyl peroxydicarbonate and 70 g of ethyl acetate) was added, the pressure was increased to 1.1 MPa, the polymerization reaction was started, the temperature of the polymerization kettle was controlled to slowly rise to 30° C., the reaction was carried out for 6 h, when the pressure in the polymerization kettle was lower than 0.5 MPa, the polymerization reaction was stopped, the remaining VDF monomer in the kettle was recovered, the polymer in the kettle was centrifuged, washed, and dried to obtain 11.7 kg of polyvinylidene fluoride powdered resin, the yield of which was 97.5% after testing, and the defective structure of head-to-head and tail-to-tail connection in the structure was less than 4.7%.

[0032] Example 6 The preparation method of polyvinylidene fluoride comprises the following steps: 20 L of deionized water was added to a 40 L closed polymerization kettle, the air in the kettle was evacuated, and the oxygen content in the kettle was replaced by nitrogen until it was less than 10 ppm, 1 g of methyl cellulose was added, the temperature of the polymerization kettle was controlled at 10±2° C., 12 kg of VDF monomer was added at one time, 50 g of the organic phase solution of diisopropyl peroxydicarbonate prepared in Example 2 (containing 15 g of diisopropyl peroxydicarbonate and 35 g of ethyl acetate) was added, the pressure was increased to 1.2 MPa, the polymerization reaction was started, the temperature of the polymerization kettle was controlled to slowly rise to 35° C., the reaction was carried out for 5 h, when the pressure in the polymerization kettle was lower than 0.5 MPa, the polymerization reaction was stopped, the remaining VDF monomer in the kettle was recovered, the polymer in the kettle was centrifuged, washed, and dried to obtain 11.3 kg of polyvinylidene fluoride powdered resin, the yield of which was 94.2% after testing, and the defective structure of head-to-head and tail-to-tail connection in the structure was less than 4.5%.

[0033] Comparative Example 1 A method for preparing diisopropyl peroxydicarbonate comprises the following steps: Add isopropyl chloroformate to a dried and cooled three-necked flask, cool the beaker to -5°C by a salt bath, turn on the stirrer, add a 27% mass concentration of hydrogen peroxide solution, and when the temperature of the mixture in the bottle is stabilized at -5°C, add a 32% mass concentration of sodium hydroxide solution to the dropping funnel, and then slowly add it dropwise to the above three-necked flask, control the dropping time to 75min, and control the reaction temperature to be lower than 10°C during the reaction. After the sodium hydroxide solution is added dropwise, continue the reaction for 32min to obtain diisopropyl peroxydicarbonate; wherein the molar ratio of isopropyl chloroformate, sodium hydroxide, and hydrogen peroxide is 1:1.03:0.6.

[0034] According to the iodine titration method for determination of organic peroxide content in GB / T 32102-2015, the yield of diisopropyl peroxydicarbonate was 78.9%.

[0035] Comparative Example 2 A method for preparing diisopropyl peroxydicarbonate comprises the following steps: Add isopropyl chloroformate and ethyl acetate into a three-necked flask, turn on the stirrer, add a hydrogen peroxide solution with a mass concentration of 27% and a sodium hydroxide solution with a mass concentration of 32% in sequence, and continue the reaction for 32 minutes to obtain diisopropyl peroxydicarbonate; wherein, the molar ratio of isopropyl chloroformate, sodium hydroxide, and hydrogen peroxide is 1:1.03:0.6, and the amount of ethyl acetate used is 3 times the mass of isopropyl chloroformate.

[0036] According to the iodine titration method for determination of organic peroxide content in GB / T 32102-2015, the yield of diisopropyl peroxydicarbonate was 10%.

[0037] Comparative Example 3 The preparation method of polyvinylidene fluoride comprises the following steps: 20L of deionized water was added to a 40L closed polymerization kettle, the air in the kettle was evacuated, and the oxygen content in the kettle was replaced by nitrogen until it was less than 10ppm, 2g of methyl cellulose was added, the temperature of the polymerization kettle was controlled at 10±2°C, 12kg of VDF monomer was added at one time, 30g of diisopropyl peroxydicarbonate prepared in Comparative Example 1, and 70g of chain transfer agent were added, and after uniform mixing, the pressure was increased to 1.1MPa to start the polymerization reaction, and the temperature of the polymerization kettle was controlled to slowly rise to 30°C and react for 6h. When the pressure in the polymerization kettle was lower than 0.5Mpa, the polymerization reaction was stopped, the remaining VDF monomer in the kettle was recovered, and the polymer in the kettle was centrifuged, washed, and dried to obtain 10.8g of polyvinylidene fluoride powdered resin. The yield was tested to be 90.0%, and the defective structure of head-to-head and tail-to-tail connection in the structure was 5.2%.

[0038] Comparative Example 4 The preparation method of polyvinylidene fluoride comprises the following steps: 20L of deionized water was added to a 40L closed polymerization kettle, the air in the kettle was evacuated, and the oxygen content in the kettle was replaced by nitrogen until it was less than 10ppm, 2g of methyl cellulose was added, the temperature of the polymerization kettle was controlled at 10±2°C, 12kg of VDF monomer was added at one time, 100g of the diisopropyl peroxydicarbonate organic phase solution prepared in Comparative Example 2 (containing 10g of diisopropyl peroxydicarbonate and 90g of ethyl acetate) was added, the pressure was increased to 1.1MPa, the polymerization reaction was started, the temperature of the polymerization kettle was controlled to slowly rise to 30°C, and the reaction was carried out for 6h. When the pressure in the polymerization kettle was lower than 0.5Mpa, the polymerization reaction was stopped, the remaining VDF monomer in the kettle was recovered, and the polymer in the kettle was centrifuged, washed, and dried to obtain 5.9g of polyvinylidene fluoride powdered resin. The yield was 49.2% after testing, and the defective structure of head-to-head and tail-to-tail connection in the structure was 5.5%.

[0039] Comparative Example 5 The preparation method of polyvinylidene fluoride (refer to the relevant method in the existing patent CN103524647A) comprises the following steps: In a 40L closed polymerization kettle, 20L of deionized water, 2g of methyl cellulose, 12kg of VDF monomer were added at one time, and 100g of diisopropyl peroxydicarbonate organic solution prepared in Example 2 (containing 30g of diisopropyl peroxydicarbonate and 70g of ethyl acetate) were added to start the polymerization reaction. The temperature of the polymerization kettle was controlled to slowly rise to 30°C, and the polymerization reaction was stopped after 20h of reaction. The remaining VDF monomer in the kettle was recovered, and the polymer in the kettle was centrifuged, washed, and dried to obtain 10.5kg of polyvinylidene fluoride powdered resin. After testing, the yield was 87.5%, and the defective structure of head-to-head and tail-to-tail connection in the structure was 5.9%.

[0040] It can be seen from the results of Examples 1-3 that the present invention, by strictly controlling the addition sequence, addition method and process conditions of the raw materials, is not only highly safe, but also has a high yield and good stability of the obtained diisopropyl peroxydicarbonate; it can be directly used in the preparation of polyvinylidene fluoride without adding a chain transfer agent, and can be polymerized under conditions of relatively low temperature, thereby improving the regularity of the polyvinylidene fluoride molecular chain, reducing abnormal structures, and greatly improving the comprehensive performance of polyvinylidene fluoride.

[0041] In Comparative Example 1, no ester-soluble organic solvent is used in the process of preparing diisopropyl peroxydicarbonate. Not only the risk of explosion must be paid attention to during the reaction, but also the yield of the obtained product is low. In addition, the preparation of polyvinylidene fluoride requires the addition of a chain transfer agent, and the steps are more complicated, thereby increasing the preparation risk and increasing its defects to a certain extent.

[0042] In Comparative Example 2, the raw materials were directly mixed, and sodium hydroxide solution was not added dropwise to prepare diisopropyl peroxydicarbonate, which not only increased the risk of the reaction but also seriously affected its yield. The product obtained by directly using it to prepare polyvinylidene fluoride was low and its defects were further increased.

[0043] In Comparative Example 5, polyvinylidene fluoride is prepared by the existing method. Although diisopropyl peroxydicarbonate prepared by the present invention is used, since the air content and temperature in the polymerization reactor are not controlled in the early stage, not only the preparation risk is increased, but also the yield is reduced, the defects are increased, and its performance is directly affected.

[0044] In summary, the present invention strictly controls the addition sequence, addition method and process conditions of the raw materials, and has good safety and high yield. The prepared diisopropyl peroxydicarbonate is a solution dissolved in an organic phase, has good stability, and has a lower risk of decomposition and explosion. It can be directly used to prepare polyvinylidene fluoride, or can be prepared as needed without storage, which greatly reduces the storage risk, and does not require the addition of a chain transfer agent. The obtained polyvinylidene fluoride resin has few structural defects, good molecular chain regularity, high crystallinity, excellent comprehensive performance, and good market competitiveness.

[0045] Finally, it should be emphasized that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modifications, equivalent substitutions, 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 diisopropyl peroxydicarbonate, characterized in that: The steps include: S1. Add isopropyl chloroformate and ester-soluble organic solution to a dried and cooled three-necked flask, turn on the stirrer, add hydrogen peroxide solution, and when the temperature of the mixture in the flask is stabilized at -5°C, add sodium hydroxide solution to the dropping funnel, and then slowly add it dropwise to the above three-necked flask, control the dropping time to 60-90min, and control the reaction temperature to be lower than 10°C during the reaction. After the sodium hydroxide solution is added dropwise, continue the reaction for 30-35min; S2. Pour the mixed solution after the reaction of S1 into a separatory funnel, separate the organic phase, wash it with water 2-3 times, and dry it with anhydrous sodium sulfate to obtain the product.

2. The preparation method according to claim 1, characterized in that: In S1, the molar ratio of isopropyl chloroformate, sodium hydroxide and hydrogen peroxide is 1:1.02-1.05:0.55-0.

7.

3. The preparation method according to claim 1, characterized in that: In S1, the ester-soluble organic solution is any one or more of ethyl acetate, diethyl malonate, and diethyl carbonate, and the added amount is 1-3 times the mass of isopropyl chloroformate.

4. The preparation method according to claim 1, characterized in that: In S1, before turning on the stirrer, the temperature in the flask was cooled to -5°C by using an ice-salt bath.

5. The preparation method according to claim 1, characterized in that: In S1, the mass concentration of the hydrogen peroxide solution is 27%; the mass concentration of the sodium hydroxide solution is 32%.

6. The preparation method according to claim 1, characterized in that: In S1, the sodium hydroxide solution is cooled to 0°C in an ice water bath in advance.

7. The preparation method according to claim 1, characterized in that: In S2, the water used for washing is ice water.

8. Use of diisopropyl peroxydicarbonate prepared by the preparation method according to any one of claims 1 to 7 in the preparation of polyvinylidene fluoride, characterized in that: The application method is as follows: deionized water is added to a closed polymerization kettle, the air in the kettle is evacuated, and the oxygen content in the kettle is replaced by nitrogen until it is less than 10ppm, methyl cellulose is added, the temperature of the polymerization kettle is controlled at 10±2°C, VDF monomer is added at one time, diisopropyl peroxydicarbonate solution is added, the pressure is increased to 1-1.2MPa, the polymerization reaction is started, the temperature of the polymerization kettle is controlled to rise slowly to 20-35°C, the reaction is carried out for 5-8h, and when the pressure in the polymerization kettle is lower than 0.5Mpa, the polymerization reaction is stopped, the remaining VDF monomer in the kettle is recovered, and the polymer in the kettle is centrifuged, washed, and dried to obtain a powdered resin.

9. The use according to claim 8, characterized in that: The amount of deionized water added is 1-2 times the weight of the VDF monomer; the amount of methyl cellulose added is 0.08-0.4‰ the weight of the VDF monomer.

10. The use according to claim 8, characterized in that: The added amount of the diisopropyl peroxydicarbonate solution is 4.2-8.3‰ of the weight of the VDF monomer.