Process for the preparation of di(2-ethylhexyl) peroxydicarbonate in one step and use thereof

Abstract

The application provides a one-step method for preparing di(2-ethylhexyl) peroxydicarbonate and application. The micro-packed bed reactor device is used to continuously prepare di(2-ethylhexyl) peroxydicarbonate by the one-step method, the synthesis method uses chloroformic acid (2-ethyl) hexyl ester as raw material, the raw material is cheap and easy to obtain, the production cost is low, the method is safe and environmentally friendly; the synthesis method uses a phase transfer catalyst, compared with the kettle process, the reaction time is greatly reduced, and the safety factor is higher. By using the synthesis method, the yield of di(2-ethylhexyl) peroxydicarbonate can reach 99.2%, the purity can reach 99.5%, the production process is simple, continuous production can be realized, the operation safety is higher, the selectivity is higher, the process can be directly amplified, and the industrial production is facilitated.

Description

Technical Field

[0001] This invention belongs to the field of chemical synthesis technology, specifically relating to a one-step method for preparing di(2-ethylhexyl) peroxide dicarbonate and its application. Background Technology

[0002] Organic peroxides are organic compounds formed by the substitution of one or two hydrogen atoms in hydrogen peroxide. They are mainly used as initiators for free radical polymerization, initiators for curing unsaturated polyesters, crosslinking agents for polymers, oxidants for organic synthesis, bleaching agents, and bactericides. Di(2-ethylhexyl) percarbonate (EHP) is a colorless, transparent liquid and a highly active initiator. It easily decomposes into free radicals under heat or light. It is usually obtained by a substitution reaction of hydrogen peroxide, sodium hydroxide, and (2-ethylhexyl) chloroformate. Therefore, it can be widely used as an initiator for free radical reactions, such as in the production of polyethylene, PVC, and polyvinyl acetate. Compared with other percarbonate initiators, it has better stability during transportation and storage. Because it is insoluble in water, it is less likely to produce aqueous polymers during polymerization, and the polymerization reaction is exothermic and uniform, easily achieving a uniform reaction rate. Therefore, di(2-ethylhexyl) percarbonate has become one of the most promising initiators. The existing preparation methods are as follows:

[0003] Existing technology 1: The method for preparing di(2-ethylhexyl) peroxide dicarbonate disclosed in Chinese patent CN102443081A involves preparing a peroxide solution using an alkaline solution and a strong oxide, followed by intermittent preparation of an emulsion-type di(2-ethylhexyl) peroxide dicarbonate, with a reaction time of 3-4 hours. This method is a batch process, with a long reaction time, poor heat transfer performance, and high safety risks.

[0004] Prior art 2: Chinese patent CN104370789A discloses a continuous flow method for preparing bis(2-ethylhexyl) peroxide dicarbonate. This method involves first stably introducing an alkaline aqueous solution and hydrogen peroxide into reactor #1 for reaction, followed by reaction into reactor #2. A chloroformic acid-2-ethylhexyl ester solution is then stably introduced into reactor #2 to react with the products of the alkaline aqueous solution and hydrogen peroxide. This method involves relatively low reaction temperatures and long reaction times, and the use of a portion of the pipeline for delaying the reaction affects product quality. The excessively long pipeline leads to excessive pressure drop, increased energy consumption, and increased operational difficulty.

[0005] Prior art 3: Chinese patent CN109265384A discloses a method for preparing di(2-ethylhexyl) peroxide dicarbonate. First, sodium peroxide solution is synthesized in a first microreactor using hydrogen peroxide and sodium hydroxide. Then, di(2-ethylhexyl) peroxide dicarbonate is synthesized in a second microreactor using a solution of chloroformate-2-ethylhexyl ester. The reaction is then continued in a self-made reactor. The reaction time is 20-40 minutes. This method, using a microreactor, cannot avoid the problem of reduced reaction rate due to gas generation in the microchannels; therefore, a self-made reactor is used to continue the reaction.

[0006] Therefore, there is an urgent need to develop a method for preparing di(2-ethylhexyl) peroxide dicarbonate that is easy to operate, has a high heat and mass transfer rate, a low risk factor, is easy to scale up, and has a high yield and high purity. Summary of the Invention

[0007] To address the aforementioned shortcomings, this invention provides a one-step method for preparing di(2-ethylhexyl) peroxide dicarbonate and its application. This invention employs a micro-packed bed reactor for a one-step continuous preparation of di(2-ethylhexyl) peroxide dicarbonate. This synthesis method uses (2-ethylhexyl) chloroformate as a raw material, which is inexpensive, readily available, and has low production costs, while being safe and environmentally friendly. The method utilizes a phase transfer catalyst, significantly reducing reaction time compared to batch processes and offering a higher safety factor. Using the synthesis method described in this invention, the yield of di(2-ethylhexyl) peroxide dicarbonate can reach 99.2%, and the purity can reach 99.5%. The production process is simple, allows for continuous production, has high operational safety and high selectivity, and can be directly scaled up, which is beneficial for industrial production.

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

[0009] On one hand, the present invention provides a one-step method for preparing di(2-ethylhexyl) peroxide dicarbonate, the method comprising the following steps:

[0010] (1) Prepare solution 1 by mixing hydrogen peroxide aqueous solution and phase transfer catalyst;

[0011] (2) The solution 1 prepared in step (1), sodium hydroxide aqueous solution and (2-ethylhexyl) chloroformate solution are pumped into a micro mixer for premixing and then into a micro packed bed reactor for reaction to obtain reaction solution 2.

[0012] (3) The reaction solution 2 prepared in step (2) is passed into a separation tank for static separation and the upper oil phase is taken to obtain di(2-ethylhexyl) peroxide dicarbonate.

[0013] Specifically, the reaction formula of the method is as follows:

[0014] 2NaOH·H2O2→Na2O2+2H2O

[0015] 2R-Cl + Na₂O₂ → ROOR + 2NaCl;

[0016] The structural formula for R is as follows:

[0017]

[0018] Specifically, the mass ratio of the hydrogen peroxide aqueous solution to the phase transfer catalyst in step (1) is 50-150:1.

[0019] Preferably, the mass ratio of the hydrogen peroxide aqueous solution to the phase transfer catalyst in step (1) is 100:1.

[0020] Specifically, the phase transfer catalyst mentioned in step (1) includes, but is not limited to, benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride.

[0021] Preferably, the phase transfer catalyst in step (1) is tetrabutylammonium chloride.

[0022] Specifically, the hydrogen peroxide aqueous solution described in step (1) is placed in an ice-water bath in the dark before mixing.

[0023] Specifically, the concentration of the hydrogen peroxide aqueous solution mentioned in step (1) is 15-30 wt%.

[0024] Preferably, the concentration of the hydrogen peroxide aqueous solution in step (1) is 30 wt%.

[0025] Specifically, the molar ratio of the hydrogen peroxide aqueous solution in step (1) to the sodium hydroxide aqueous solution in step (2) is 1.0:1.8-2.0.

[0026] Preferably, the molar ratio of the hydrogen peroxide aqueous solution in step (1) to the sodium hydroxide aqueous solution in step (2) is 1.0:2.0.

[0027] Specifically, the molar ratio of the hydrogen peroxide aqueous solution in step (1) to the (2-ethylhexyl) chloroformate aqueous solution in step (2) is 0.6-0.8:1.0.

[0028] Preferably, the molar ratio of the hydrogen peroxide aqueous solution in step (1) to the (2-ethylhexyl) chloroformate aqueous solution in step (2) is 0.55-0.80:1.00.

[0029] Specifically, the concentration of the sodium hydroxide aqueous solution described in step (2) is 10-20 wt%.

[0030] Preferably, the concentration of the sodium hydroxide aqueous solution in step (2) is 10 wt%.

[0031] Specifically, the concentration of the aqueous solution of (2-ethylhexyl) chloroformate described in step (2) is 95-99 wt%.

[0032] Preferably, the concentration of the aqueous solution of (2-ethylhexyl) chloroformate in step (2) is 98%.

[0033] Preferably, the reaction temperature in step (2) is 50°C.

[0034] Preferably, the reaction time in step (2) is 8 minutes.

[0035] Specifically, the volume of the micro-filled bed described in step (2) is 0.5-60 mL.

[0036] Preferably, the volume of the micro-filled bed in step (2) is 15-60 mL.

[0037] Specifically, the micro-filled bed described in step (2) is filled with inert glass beads.

[0038] Preferably, the diameter of the inert glass beads is 200-400 μm.

[0039] Specifically, the micro-filled bed described in step (2) has a porosity of 50-60%.

[0040] Preferably, the micro-filled bed described in step (2) has a filling bed porosity of 55%.

[0041] On the other hand, the present invention provides a microreactor for the above preparation method.

[0042] Specifically, the microreactor includes a micromixer and a microfilled bed module connected sequentially via connecting pipes. The reaction materials are fed into the micromixer and subsequent equipment via a precise and low-pulsation pump.

[0043] Specifically, the inner diameter of the connecting tube of the microreactor is 1-30 mm.

[0044] More specifically, the inner diameter of the connecting tube of the microreactor is 1-20 mm.

[0045] Preferably, the inner diameter of the connecting tube of the microreactor is 10 mm.

[0046] On the other hand, the present invention provides the application of the above-mentioned preparation method.

[0047] Specifically, the application is described in the preparation of di(2-ethylhexyl) peroxide dicarbonate and / or its analogues.

[0048] Preferably, the di(2-ethylhexyl) peroxide dicarbonate analogue is a derivative of di(2-ethylhexyl) peroxide dicarbonate, a pharmaceutically acceptable salt thereof, its tautomer and / or its stereoisomer.

[0049] The technical effects achieved by this invention are as follows:

[0050] (1) The preparation method provided by the present invention avoids the use of highly toxic phosgene and uses (2-ethylhexyl) chloroformate as raw material. The raw material is cheap and readily available, the production cost is low, and it is safe and environmentally friendly.

[0051] (2) This invention employs a one-step method to synthesize di(2-ethylhexyl) peroxide dicarbonate using a phase transfer catalyst. Compared with the batch process, the reaction time is significantly reduced, and the safety factor is higher. Compared with the reported microchannel technology, the micro-packed bed reactor used in this invention can effectively alleviate the problem of reduced reaction rate caused by reaction gas production, and significantly improve the space-time yield.

[0052] (3) Using the synthesis method described in this invention, the yield of di(2-ethylhexyl) peroxide dicarbonate can reach 99.2%, and the purity can reach 99.5%.

[0053] (4) The preparation method provided by the present invention can effectively reduce the reaction time, and the reaction is fast, with high yield and high safety. The production method of the present invention is simple, can be continuously produced, has high operational safety and high selectivity, and can be directly scaled up, which is beneficial to industrial production. Attached Figure Description

[0054] Figure 1 This is a schematic diagram of the process. Detailed Implementation

[0055] The following non-limiting embodiments are intended to enable those skilled in the art to gain a more comprehensive understanding of the present invention, but do not limit the invention in any way. The following content is merely an exemplary description of the scope of protection claimed by the present invention, and those skilled in the art can make various changes and modifications to the present invention based on the disclosed content, and such changes should also fall within the scope of protection claimed by the present invention.

[0056] When numerical ranges are given in the embodiments, it should be understood that, unless otherwise stated in the invention, both endpoints of each numerical range and any value between the two endpoints may be selected. Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0057] The present invention will be further described below by way of specific embodiments. Unless otherwise specified, all chemical reagents used in the embodiments of the present invention are obtained through conventional commercial means.

[0058] Example 1

[0059] A one-step method for preparing di(2-ethylhexyl) peroxide dicarbonate using a micro-packed bed reactor specifically includes the following steps:

[0060] (1) Prepare a mixed solution by mixing 16 mL of 30% hydrogen peroxide aqueous solution with 0.176 g of tetrabutylammonium chloride.

[0061] (2) 16 mL of the mixed solution, 80 mL of 10% sodium hydroxide solution, and 40 mL of 98% (2-ethylhexyl) chloroformate were pumped into a micromixer for premixing, and then fed into a micro-packed bed reactor for reaction. The micro-packed bed reaction temperature T1 was 50 °C, and the micro-packed bed reaction time t1 was 8 min. After the reaction, the mixture was allowed to settle and separate into layers in a separation tank. The aqueous phase was discharged by gravity, and the resulting oil phase was frozen. The precipitated ice residue was filtered off to obtain di(2-ethylhexyl) peroxide dicarbonate. The reaction yield was determined according to standard T / CPCIF 0092-2021.

[0062] Comparative Example 1

[0063] 16 mL of a 30% hydrogen peroxide aqueous solution, 80 mL of a 10% sodium hydroxide solution, and 40 mL of a 98% (2-ethylhexyl) chloroformate solution were premixed in a micromixer, and then fed into a micro-packed bed reactor for reaction. The reaction temperature (T1) was 50 °C, and the reaction time (t1) was 8 min. After the reaction, the mixture was allowed to settle and separate into layers in a separation tank. The aqueous phase was discharged by gravity, and the resulting oil phase was frozen. The precipitated ice residue was filtered off to obtain di(2-ethylhexyl) peroxide dicarbonate. The reaction yield was determined according to standard T / CPCIF 0092-2021.

[0064] Comparative Example 2

[0065] The only difference between Comparative Example 2 and Example 1 is that the "micro-filled bed reaction time t1 is 8 min" is changed to "micro-filled bed reaction time t1 is 2 min".

[0066] Comparative Example 3

[0067] The only difference between Comparative Example 3 and Example 1 is that the "micro-filled bed reaction time t1 is 8 min" is changed to "micro-filled bed reaction time t1 is 4 min".

[0068] Comparative Example 4

[0069] The only difference between Comparative Example 4 and Example 1 is that "the reaction temperature T1 of the micro-filled bed is 50°C" is changed to "the reaction temperature T1 of the micro-filled bed is 20°C".

[0070] Comparative Example 5

[0071] The only difference between Comparative Example 5 and Example 1 is that "the reaction temperature T1 of the micro-filled bed is 50°C" is changed to "the reaction temperature T1 of the micro-filled bed is 30°C".

[0072] Comparative Example 6

[0073] The only difference between Comparative Example 6 and Example 1 is that "the reaction temperature T1 of the micro-filled bed is 50°C" is changed to "the reaction temperature T1 of the micro-filled bed is 40°C".

[0074] Comparative Example 7

[0075] The preparation of di(2-ethylhexyl) peroxide dicarbonate by a two-step method includes the following steps:

[0076] (1) Prepare a mixed solution by mixing 16 mL of 30% hydrogen peroxide aqueous solution with 0.176 g of tetrabutylammonium chloride.

[0077] (2) First step reaction: 16 mL of mixed solution and 80 mL of 10% sodium hydroxide solution were pumped into a micro mixer for premixing, and then entered into a microchannel reactor (microchannel inner diameter 1 mm, microchannel length 2 m) for reaction (reaction temperature T is 10℃, reaction time t is 2 min) to synthesize peroxide and obtain reaction solution B (sodium peroxide solution).

[0078] (3) Second step reaction: Reaction solution B and 40 mL of 98% (2-ethylhexyl) chloroformate were introduced into the micro-packed bed reactor described above for reaction. The micro-packed bed reaction temperature T1 was 50℃, and the micro-packed bed reaction time t1 was 8 min. After the reaction, the mixture was passed into a separation tank for settling and separation. The aqueous phase was discharged by gravity, and the resulting oil phase was frozen. The precipitated ice residue was filtered off to obtain di(2-ethylhexyl) peroxide dicarbonate. The reaction yield was determined according to standard T / CPCIF 0092-2021.

[0079] Comparative Example 8

[0080] The only difference between Comparative Example 8 and Comparative Example 7 is that “microchannel length is 2m” in step (2) is changed to “microchannel length is 4m”; and “reaction time t is 2min” in step (2) is changed to “reaction time t is 4min”.

[0081] Comparative Example 9

[0082] The only difference between Comparative Example 9 and Comparative Example 7 is that the "reaction temperature T is 10℃" in step (2) is changed to "reaction temperature T is 15℃".

[0083] Comparative Example 10

[0084] The only difference between Comparative Example 10 and Example 1 is that the phase transfer catalyst “tetrabutylammonium chloride” in step (1) is replaced with “18-crown-6”.

[0085] Comparative Example 11

[0086] The only difference between Comparative Example 11 and Example 1 is that the "micro-filled bed reaction time t1 is 8 min" is changed to "micro-filled bed reaction time t1 is 6 min".

[0087] Comparative Example 12

[0088] The only difference between Comparative Example 12 and Example 1 is that the "micro-filled bed reaction time t1 is 8 min" is changed to "micro-filled bed reaction time t1 is 12 min".

[0089] Comparative Example 13

[0090] The only difference between Comparative Example 13 and Example 1 is that "the reaction temperature T1 of the micro-filled bed is 50°C" is changed to "the reaction temperature T1 of the micro-filled bed is 45°C".

[0091] Comparative Example 14

[0092] The only difference between Comparative Example 14 and Example 1 is that "the reaction temperature T1 of the micro-filled bed is 50°C" is changed to "the reaction temperature T1 of the micro-filled bed is 55°C".

[0093] Experimental Example 1

[0094] The di(2-ethylhexyl) peroxide dicarbonate prepared in Examples 1 and Comparative Examples 1-14 was analyzed by HPLC to determine its content, and the yield was calculated based on the content. The purity and yield of di(2-ethylhexyl) peroxide dicarbonate were determined and calculated according to standard T / CPCIF 0092-2021 "Initiator for Polymerization of Vinyl Chloride - Di(2-ethylhexyl) Peroxide (EHP)". The results are shown in Table 1.

[0095] Table 1 Yield

[0096]

[0097] The results showed that the yield and purity of the di(2-ethylhexyl) peroxide dicarbonate prepared in Example 1 of the present invention were both above 99%, exhibiting the highest yield and purity.

[0098] Experiment Example 2 is compared with existing technologies.

[0099] Table 2 compares the technology with existing technologies.

[0100]

[0101] The results show that the di(2-ethylhexyl) peroxide dicarbonate prepared continuously in one step using a micro-packed bed reactor device provided by the present invention has a yield of over 99% and the highest purity.

[0102] The above detailed description is a specific illustration of one feasible embodiment of the present invention, and this embodiment is not intended to limit the patent scope of the present invention. It should be noted that all equivalent implementations or modifications made without departing from the present invention should be included within the scope of the technical solution of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A one-step method for preparing di(2-ethylhexyl) peroxide dicarbonate, characterized in that, The method includes the following steps: (1) Prepare solution 1 by mixing hydrogen peroxide aqueous solution and phase transfer catalyst; (2) The solution 1, sodium hydroxide aqueous solution and (2-ethylhexyl) chloroformate solution prepared in step (1) are pumped into a micro mixer for premixing and then fed into a micro packed bed reactor for reaction to obtain reaction solution 2; (3) The reaction solution 2 prepared in step (2) is passed into a separation tank for static separation and the upper oil phase is taken to obtain di(2-ethylhexyl) peroxide dicarbonate; The phase transfer catalyst mentioned in step (1) includes one or more of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, and tetradecyltrimethylammonium chloride; The reaction temperature in step (2) is 50℃; the reaction time is 8min; the molar ratio of the hydrogen peroxide aqueous solution in step (1) to the sodium hydroxide aqueous solution in step (2) is 1:1.8-2.

0.

2. The method according to claim 1, characterized in that, The mass ratio of the hydrogen peroxide aqueous solution to the phase transfer catalyst in step (1) is 50-150:

1.

3. The method according to claim 1, characterized in that, The hydrogen peroxide aqueous solution described in step (1) is placed in an ice-water bath in the dark before mixing.

4. The method according to claim 1, characterized in that, The concentration of the hydrogen peroxide aqueous solution in step (1) is 15-30 wt%; the concentration of the sodium hydroxide aqueous solution in step (2) is 10-20 wt%; and the concentration of (2-ethylhexyl) chloroformate in step (2) is 95-99 wt%.

5. The method according to claim 1, characterized in that, The molar ratio of the hydrogen peroxide aqueous solution in step (1) to the (2-ethylhexyl) chloroformate in step (2) is 0.6-0.8:

1.

6. The method according to claim 1, characterized in that, The micro-filled bed reactor described in step (1) is filled with inert glass beads with a diameter of 200-400 μm; the porosity of the filled bed is 55%.

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