A process for the preparation of di(2-ethylhexyl) peroxydicarbonate

Abstract

The application belongs to the technical field of chemical engineering and specifically relates to a method for preparing di(2-ethylhexyl) peroxydicarbonate. The preparation method comprises the following steps: mixing potassium hydroxide solution and hydrogen peroxide to obtain reaction liquid A; adding a phase transfer catalyst to the reaction liquid A, and then mixing the reaction liquid A with chloroformic acid-2-ethylhexyl ester solution to obtain reaction liquid B; and cooling and washing the reaction liquid B to obtain di(2-ethylhexyl) peroxydicarbonate. The micro-channel reactor is used to continuously produce di(2-ethylhexyl) peroxydicarbonate. The reactants are reacted in multiple temperature zones, thereby breaking through the limitation of the reaction temperature (less than 44 DEG C). Di(2-ethylhexyl) peroxydicarbonate can be synthesized at high temperature, and the product has high yield, high purity and good reproducibility.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of chemical industry, and particularly relates to a method for preparing di(2-ethylhexyl) peroxydicarbonate. BACKGROUND

[0002] Di(2-ethylhexyl) peroxydicarbonate is also called initiator EHP, di-octyl peroxydicarbonate, and is simply referred to as EHP. EHP is easy to decompose into free radicals under the conditions of heat or light, and therefore can be widely used as an initiator of free radical reaction, such as the production of polyethylene, PVC, polyvinyl acetate, etc. The use of EHP as an initiator for the polymerization of chloroethylene has the advantages of high initiation rate, short polymerization time, low polymerization temperature, small use amount, good product quality, and low residual toxicity, etc. The theoretical active oxygen content of EHP is 4.62%, which is higher than that of other initiators. The traditional kettle production process of EHP is determined as a peroxidation reaction, and needs to be changed into a full-process automatic process.

[0003] In addition, the main hazards of EHP are as follows: (1) EHP contains peroxide groups (-O-O-), which is an energetic substance. Since the peroxide bond has weak binding force, the energy required for its rupture is not large, and it is extremely sensitive to heat, vibration, impact or friction, and is extremely easy to decompose and even explode; (2) Peroxides have the risk of combustion and explosion when they come into contact with reducing agents, copper ions and other metal ions, and acids and bases, and will cause combustion and explosion when they come into contact with high temperature and open flame; (3) It is a strong exothermic reaction.

[0004] The current kettle production process mainly includes the following steps: distilled water and sodium hydroxide solid are mixed, the mixture is cooled to 16 DEG C by adding chilled brine, hydrogen peroxide solution is added, and the reaction temperature is controlled to be not higher than 23 DEG C; when the temperature is below 6 DEG C, chloroformic acid-2-ethylhexyl ester is added dropwise, which needs to be completed within 1 hour, and the low-temperature constant-temperature reaction is carried out until ripples appear on the surface of the original liquid and spread over the liquid surface, after the reaction is completed, the water is separated by standing. In the traditional production reaction process, the temperature and concentration are not uniform, and the mixing is poor, and the yield of BNP prepared is only about 80%, and the purity is also poor. In the process of adding raw materials, new decanoyl chloride needs to be added dropwise to control the reaction, which is greatly affected by human factors, and is harmful to the human body, and finally leads to low purity of the product and poor repeatability.

[0005] The micro-channel reactor is a continuous flow tubular reactor with high safety performance, high raw material utilization rate and low green environmental protection pollutant emission, and is generally a micro-structure reaction equipment manufactured through micro-processing technology and precision machining technology; the reactor mainly adopts special glass material and silicon carbide material, the channel size of the reaction raw material mixture in the micro-channel reactor is very small, so compared with the traditional tubular reactor, the mixing intensity and mass and heat transfer rate are 100 times higher, and the micro-channel reactor has no amplification effect and can quickly complete industrial upgrading; the micro-channel reactor is widely applied to nitration reaction, oxidation reaction, photo reaction and diazotization reaction, reaction heat can be quickly removed, and safety is improved.

[0006] Chinese patent application CN201910581095.3 discloses a synthesis method of di(2-ethylhexyl) peroxydicarbonate, and the patent adopts a micro-channel reactor for synthesis, reaction temperature is controlled in stages, the temperature of the first-stage micro-channel reactor is 10-15 DEG C, the residence time is 1-1.5 min, the reaction temperature of the second-stage micro-channel reactor is 30-44 DEG C, and the residence time is 2-5 min, and the yield of the patent is about 98%. The patent uses high-concentration raw materials for production, which increases the cost of raw materials, and the length of each mixing substrate of the micro-channel reactor is 1-5 m, the overall reactor volume is too large, the equipment occupation area is increased, the reaction temperature is between 10 DEG C and 44 DEG C, mass transfer cannot be well improved to increase the reaction rate, the residence time is too long, and the mixing substrate is also long, so that the product is decomposed more.

[0007] From the prior art, the process for continuously preparing EHP still has problems of strict control of normal temperature reaction and long total reaction time, which increases the difficulty of industrialization. In view of this, the present application provides a method for continuously preparing di(2-ethylhexyl) peroxydicarbonate by using a multi-temperature-zone multi-module micro-channel reactor at high temperature. SUMMARY

[0008] In view of the deficiencies of the prior art, the present application provides a method for preparing di(2-ethylhexyl) peroxydicarbonate by using a multi-temperature-zone multi-module micro-channel reactor, which can realize high-temperature preparation of di(2-ethylhexyl) peroxydicarbonate, has short reaction time, high product yield, small harm to human body, and can replace the micro-channel module in time without affecting the overall production when there is local leakage.

[0009] In order to achieve the above-mentioned purposes of the present application, the specific technical scheme adopted by the present application is as follows:

[0010] The method for preparing di(2-ethylhexyl) peroxydicarbonate according to the present application comprises the following steps:

[0011] (1) mixing potassium hydroxide solution and hydrogen peroxide to obtain reaction liquid A;

[0012] (2) adding phase transfer catalyst into reaction liquid A, then mixing with chloroformic acid-2-ethyl hexyl ester solution to obtain reaction liquid B;

[0013] (3) cooling and washing reaction liquid B to obtain the product.

[0014] Preferably, the concentration of potassium hydroxide solution in step (1) is 15-25wt%, the flow rate of potassium hydroxide is 20-150g / min; the concentration of hydrogen peroxide is 20-30wt%, preferably 27.5%, the flow rate of hydrogen peroxide is 8-60g / min; the molar ratio of potassium hydroxide to hydrogen peroxide is 1:1-1.5.

[0015] Preferably, the potassium hydroxide solution and hydrogen peroxide in step (1) are mixed in the premixing zone of the micro-channel reactor; the premixing zone is composed of 1-3 micro-channel reactor modules connected; the reaction temperature is 5-20℃; the reaction time is 5-50s.

[0016] Further preferably, the premixing zone is composed of 2 micro-channel reactor modules connected; the reaction temperature is 10-20℃; the reaction time is 10-35s.

[0017] Preferably, in step (2), the molar ratio of chloroformic acid-2-ethyl hexyl ester to hydrogen peroxide is 1:0.7-1.5; the flow rate of chloroformic acid-2-ethyl hexyl ester is 15-90g / min.

[0018] Preferably, in step (2), the reaction liquid A and chloroformic acid-2-ethyl hexyl ester solution are mixed in the reaction zone of the micro-channel reactor; the reaction zone is composed of 3-8 micro-channel reactor modules connected; the reaction temperature is 30-80℃, and the reaction time is 30-180s.

[0019] Further preferably, the reaction zone is composed of 8 micro-channel reactor modules connected; the reaction temperature is 50-70℃, and the reaction time is 30-100s.

[0020] Preferably, in step (2), the phase transfer catalyst is 15-crown-5 ether; the addition amount of phase transfer catalyst is 1%-5% of the mass of hydrogen peroxide.

[0021] Preferably, in step (3), the reaction liquid B is cooled in the cooling zone of the micro-channel reactor; the cooling zone is composed of 1-2 micro-channel reactor modules connected; the cooling temperature is 10-30℃, and the cooling time is 2-50s.

[0022] Further preferably, the cooling temperature is 15-20℃, and the cooling time is 4-20s.

[0023] Compared with the prior art, the present application has the following beneficial effects:

[0024] 1. The present application uses a micro-channel reactor to continuously produce di(2-ethylhexyl) peroxydicarbonate, the reactants are reacted in multiple temperature zones, breaking through the limitation of reaction temperature (<44℃), di(2-ethylhexyl) peroxydicarbonate can be synthesized at high temperature, the product has high yield, high purity and good reproducibility;

[0025] 2. The micro-channel reactor used in the present application has better mixing effect and can realize mixing within milliseconds, the liquid holding capacity of each module is small, the reaction risk is low, and the reactor occupies small area;

[0026] 3. The experimental method used in the present application has small raw material concentration and small reaction molar ratio, effectively utilizes raw materials, and can better improve the mass transfer rate at high reaction temperature, has short residence time and high production capacity;

[0027] 4. Compared with the kettle type reactor, there is no amplification effect, the reaction is safe, the harm to human body is small, and if the reactor leaks, the leaking reactor can be replaced without affecting the reaction. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 is a schematic diagram of the micro-channel reactor for di(2-ethylhexyl) peroxydicarbonate in the present application. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present application are further described in detail, the described embodiments are only a part of the present application, used to explain the present application, but not to limit the present application, therefore, other embodiments obtained by other skilled persons in the art without creative labor, all belong to the protection scope of the present application.

[0030] Sodium hydroxide was purchased from Inner Mongolia Ordos Electric Metallurgical Group Co., Ltd. Potassium hydroxide was purchased from Yinchuan Kejin Chemical Raw Material Co., Ltd. Hydrogen peroxide was purchased from Yinchuan Kejin Chemical Raw Material Co., Ltd., with a purity of 27.5%. Chloroformic acid-2-ethylhexyl ester was purchased from Tianjin Jingye Fine Chemical Co., Ltd., with a purity of 99.9%.

[0031] Example 1

[0032] A synthesis method of di(2-ethylhexyl) peroxydicarbonate, the specific steps are as follows:

[0033] (1) KOH solution with a concentration of 16wt% and hydrogen peroxide with a concentration of 27.5wt% are mixed in a ratio of 1:1 to prepare a mixed solution; Figure 1The premixing zone module of the microreactor shown mixes and performs a salting reaction; the molar ratio of potassium hydroxide to hydrogen peroxide is 0.6:0.9, the flow rate of the potassium hydroxide solution is 31.69 g / min, and the flow rate of the hydrogen peroxide is 16.79 g / min; the reaction temperature of the premixing zone is 12°C, and the residence time is 20.30 s, to obtain reaction liquid A.

[0034] (2) 15C5 is added to reaction liquid A (the amount of 15C5 added is 1% of the mass of the hydrogen peroxide), and after being uniformly mixed, 99.9wt% of 2-ethylhexyl chloroformate is reacted in the reaction zone of the microreactor, which is composed of 8 microchannel mixer modules; the molar ratio of 2-ethylhexyl chloroformate to KOH is 0.6:1; the flow rate of the 2-ethylhexyl chloroformate is 30.24 g / min, the reaction temperature is 60°C, and the residence time is 50 s, to obtain reaction liquid B.

[0035] (3) Reaction liquid B flows through the cooling zone of the microreactor, which is composed of 1 microchannel mixer module, the cooling zone temperature is 18°C, and the residence time is 10.15 s. After the reaction is completed, the reaction liquid is introduced into a separation tank to perform static layering to obtain the upper oil phase, and di(2-ethylhexyl) peroxydicarbonate is obtained to perform HPLC detection.

[0036] Example 2

[0037] A method for synthesizing di(2-ethylhexyl) peroxydicarbonate, and the specific steps are as follows:

[0038] (1) A 20wt% KOH solution and a 27.5wt% hydrogen peroxide solution are mixed in the premixing zone of the microreactor, the molar ratio of potassium hydroxide to hydrogen peroxide is 0.5:0.7, the flow rate of the potassium hydroxide solution is 18.44 g / min, and the flow rate of the hydrogen peroxide is 11.40 g / min; the reaction temperature of the premixing zone is 10°C, and the residence time is 32.98 s, to obtain reaction liquid A.

[0039] (2) 15C5 is added to reaction liquid A (the amount of 15C5 added is 3% of the mass of the hydrogen peroxide), and after being uniformly mixed, 99.8wt% of 2-ethylhexyl chloroformate is reacted in the reaction zone of the microreactor, which is composed of 8 microchannel mixer modules; the molar ratio of 2-ethylhexyl chloroformate to KOH is 0.5:1; the flow rate of the 2-ethylhexyl chloroformate aqueous solution is 26.39 g / min. The reaction temperature is 50°C, and the residence time is 70 s, to obtain reaction liquid B.

[0040] (3) The reaction liquid B flows through the cooling zone of the micro-reaction device, the cooling zone is composed of one micro-channel mixer module, the temperature of the cooling zone is 20℃, and the residence time is 16.49s. After the reaction is completed, the reaction liquid is introduced into a separation tank to take the upper oil phase to obtain di(2-ethylhexyl) peroxydicarbonate for HPLC detection.

[0041] Example 3

[0042] A synthesis method of di(2-ethylhexyl) peroxydicarbonate, the specific steps are as follows:

[0043] (1) The KOH solution with a concentration of 22wt% and the hydrogen peroxide with a concentration of 27.5wt% are mixed in the premixing zone of the micro-reaction device, the molar ratio of potassium hydroxide to hydrogen peroxide is 1.14:1.16, the flow rate of the potassium hydroxide solution is 60.05g / min, and the flow rate of the hydrogen peroxide is 29.68g / min; the reaction temperature of the premixing zone is 13℃, and the residence time is 10.97s, to obtain reaction liquid A.

[0044] (2) The 15-crown-5 ether is added to the reaction liquid A (the addition amount of 15-crown-5 ether is 5% of the mass of hydrogen peroxide), and after being uniformly mixed, the 15-crown-5 ether is reacted with the chloroformic acid-2-ethylhexyl ester with a concentration of 99.8wt% in the reaction zone of the micro-reaction device, the reaction zone is composed of 8 micro-channel mixer modules connected; wherein the molar ratio of chloroformic acid-2-ethylhexyl ester to KOH is 1.14:1; the flow rate of the chloroformic acid-2-ethylhexyl ester aqueous solution is 41.47g / min, the reaction temperature is 70℃, and the residence time is 30s, to obtain reaction liquid B.

[0045] (3) The reaction liquid B flows through the cooling zone of the micro-reaction device, the cooling zone is composed of one micro-channel mixer module, the temperature of the cooling zone is 15℃, and the residence time is 5.48s. After the reaction is completed, the reaction liquid is introduced into a separation tank to take the upper oil phase to obtain di(2-ethylhexyl) peroxydicarbonate for HPLC detection.

[0046] Example 4

[0047] A synthesis method of di(2-ethylhexyl) peroxydicarbonate, the specific steps are as follows:

[0048] (1) The KOH solution with a concentration of 25wt% and the hydrogen peroxide with a concentration of 27.5wt% are mixed in the premixing zone of the micro-reaction device, the molar ratio of potassium hydroxide to hydrogen peroxide is 1.3:1.5, the flow rate of the potassium hydroxide solution is 21.30g / min, and the flow rate of the hydrogen peroxide is 8.68g / min; the reaction temperature of the premixing zone is 12℃, and the residence time is 11.86s, to obtain reaction liquid A.

[0049] (2) Add 15C5 to reaction liquid A (the amount of 15C5 added is 5% of the mass of hydrogen peroxide), mix uniformly, and then react with a 99wt% aqueous solution of 2-ethylhexyl chloroformate in the reaction zone of the microreaction device, wherein the molar ratio of 2-ethylhexyl chloroformate to KOH is 1.3:1; the flow rate of the aqueous solution of 2-ethylhexyl chloroformate is 9.20 g / min, the reaction zone is composed of 8 microchannel mixer modules; the reaction temperature is 65°C, and the residence time is 100 s, to obtain reaction liquid B.

[0050] (3) Reaction liquid B flows through the cooling zone of the microreaction device, which is composed of 1 microchannel mixer module, the cooling zone temperature is 18°C, and the residence time is 5.93 s. After the reaction is completed, the reaction liquid is introduced into a separation tank for static layering to obtain the upper oil phase to obtain di(2-ethylhexyl) peroxydicarbonate for HPLC detection.

[0051] Example 5

[0052] The operation steps in Example 1 are repeated to detect the repeatability of the method.

[0053] Comparative Example 1

[0054] A method for synthesizing di(2-ethylhexyl) peroxydicarbonate, the method used is the same as that in Example 1, the only difference is that the catalyst added in step (2) is tetra-n-butylammonium hydroxide.

[0055] Comparative Example 2

[0056] A method for synthesizing di(2-ethylhexyl) peroxydicarbonate, the method used is the same as that in Example 1, the only difference is that the feeding ratio is different, and the molar ratio of the reaction is potassium hydroxide: hydrogen peroxide: 2-ethylhexyl chloroformate = 1.4:1.1:1.

[0057] Comparative Example 3

[0058] A method for synthesizing di(2-ethylhexyl) peroxydicarbonate, the method used is the same as that in Example 1, the only difference is that the concentration of the potassium hydroxide solution is different, and the concentration is 30wt%.

[0059] Comparative Example 4

[0060] A method for synthesizing di(2-ethylhexyl) peroxydicarbonate, the method used is the same as that in Example 1, the only difference is that the reaction temperature of the reaction zone is 90°C, and the corresponding temperatures of the premixing zone and the cooling zone are set to 5°C and 10°C, respectively.

[0061] Comparative Example 5

[0062] A synthesis method of di(2-ethylhexyl) peroxydicarbonate, the method used is the same as that of Example 1, the only difference is that the residence time is different; the residence time of the reaction zone is 120 s.

[0063] Comparative Example 6

[0064] A synthesis method of di(2-ethylhexyl) peroxydicarbonate, the method used is the same as that of Example 1, the only difference is that KOH is used instead of NaOH as the alkaline substance.

[0065] Comparative Example 7

[0066] A synthesis method of di(2-ethylhexyl) peroxydicarbonate, the reaction is carried out using a traditional tank reactor, the molar ratio of the reaction is potassium hydroxide: hydrogen peroxide: chloroformic acid-2-ethylhexyl ester = 0.6:0.9:1, the reaction material is added to the tank reactor, and the reaction is carried out at 20℃ for 195 min, and the reaction is ended when the foam ripples cover the liquid surface, and the treatment method is the same as that of Example 1.

[0067] The test results of Examples 1-5 and Comparative Examples 1-7 are shown in Table 1.

[0068] Table 1 Test results

[0069]

[0070] The results show that the concentration of the alkaline solution, the feeding ratio, the reaction temperature and the residence time all have an effect on the purity and yield of the product, especially the addition of phase transfer catalyst 15-crown-5 in the present application accelerates the migration speed of sodium salt in the oil phase, effectively improving the experimental yield and purity; compared with the traditional tank production, the micro-channel production has high purity 98.87% and high yield 99.79%, has the advantages of fast mass transfer, fast removal of reaction heat, can be seamlessly scaled up, etc., so under the conditions of the present application, the limitations brought by low temperature reaction can be broken through, high purity and high yield di(2-ethylhexyl) peroxydicarbonate can be obtained in the optimal feeding ratio and shorter residence time, and the production can be intrinsically safe, green and low-carbon.

[0071] The above detailed description is a specific description of one of the feasible embodiments of the present application, and this embodiment is not used to limit the patent scope of the present application, and any equivalent implementation or change that does not deviate from the present application should be included in the scope of the technical solutions of the present application.

Claims

1. A process for the preparation of di(2-ethylhexyl) peroxydicarbonate, characterized in that, The method comprises the following steps: (1) mixing potassium hydroxide solution and hydrogen peroxide to obtain reaction liquid A; (2) adding phase transfer catalyst to reaction liquid A, and then mixing with chloroformic acid-2-ethylhexyl ester solution to obtain reaction liquid B; (3) cooling and washing reaction liquid B to obtain the product; wherein In step (1), the concentration of the potassium hydroxide solution is 15-25 wt%, and the molar ratio of potassium hydroxide to hydrogen peroxide is 1:1-1.5; In step (2), the phase transfer catalyst is 15-crown-5-ether, and the molar ratio of chloroformic acid-2-ethylhexyl ester to hydrogen peroxide is 1:0.7-1.5; In step (2), reaction liquid A and chloroformic acid-2-ethylhexyl ester solution are mixed in the reaction zone of a microchannel reactor, the reaction zone is composed of 3-8 microchannel reactor modules connected together, the reaction temperature is 50-70℃, and the reaction time is 30-100s.

2. The method of claim 1, wherein, In step (1), the flow rate of the potassium hydroxide solution is 20-150 g / min, and the concentration of hydrogen peroxide is 20-30 wt%, and the flow rate of hydrogen peroxide is 8-60 g / min.

3. The method of claim 1, wherein, In step (1), the potassium hydroxide solution and hydrogen peroxide are mixed in the premixing zone of a microchannel reactor, the premixing zone is composed of 1-3 microchannel reactor modules connected together, the reaction temperature is 5-20℃, and the reaction time is 5-50s.

4. The method of claim 3, wherein, The premixing zone is composed of 2 microchannel reactor modules connected together, the reaction temperature is 10-20℃, and the reaction time is 10-35s.

5. The method of claim 1, wherein, In step (2), the flow rate of chloroformic acid-2-ethylhexyl ester is 15-90 g / min.

6. The method of claim 1, wherein, In step (2), the reaction zone is composed of 8 microchannel reactor modules connected together.

7. The method according to any one of claims 1 to 6, characterized in that, In step (2), the addition amount of the phase transfer catalyst is 1%-5% of the mass of hydrogen peroxide.

8. The method of claim 1, wherein, In step (3), reaction liquid B is cooled in the cooling zone of a microchannel reactor, the cooling zone is composed of 1-2 microchannel reactor modules connected together, the cooling temperature is 10-30℃, and the cooling time is 2-50s.

9. The method of claim 8, wherein, The cooling temperature is 15-20℃, and the cooling time is 4-20s.

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