Process for the synthesis of di-(3,5,5-trimethylhexanoyl) peroxide and apparatus for carrying out the synthesis

Abstract

The application provides a synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide and an equipment for implementing the synthesis method. The method comprises the following steps: conveying an alkaline solution, a hydrogen peroxide solution and a 3,5,5-trimethylhexanoyl chloride solution into a micro-mixer, mixing the solutions, and then feeding the mixed solution into a micro-reactor to perform a preliminary reaction, so as to obtain a first oil-water mixture; transferring the first oil-water mixture into a reaction kettle to continue the reaction, so as to obtain a second oil-water mixture; performing liquid separation treatment on the second oil-water mixture, and obtaining an oil phase; performing post-treatment on the oil phase, so as to obtain di-(3,5,5-trimethylhexanoyl) peroxide. By taking the micro-mixer and the micro-reactor as the core to prepare di-(3,5,5-trimethylhexanoyl) peroxide, local heat accumulation can be controlled through fast heat removal, the risk of combustion and explosion of thermally unstable organic peroxide can be reduced, the contact area between the oil phase and the water phase can be increased, the reaction rate can be increased, and the production efficiency can be greatly improved.

Description

TECHNICAL FIELD

[0001] The application relates to a synthesis method and device of di-(3,5,5-trimethylhexanoyl) peroxide, in particular to a synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide based on continuous flow micro-reaction and a device for implementing the synthesis method, and belongs to the technical field of synthesis of special chemicals. BACKGROUND

[0002] Organic peroxide is a kind of organic compound characterized by peroxide bond (-O-O-), which has been widely used in chemical industry since the 1950s, mainly as initiator for polymer production, and as aid for polymer processing and modification, including alkyl hydroperoxide, dialkyl peroxide, ketone peroxide, ester peroxide, diacyl peroxide and peroxide dicarbonate, etc. With the continuous increase of global polymer demand, the application field of organic peroxide is expanding, and its development prospect is very broad.

[0003] At present, most of the enterprises in the organic peroxide industry are small in scale and single in product variety, and the overall situation is small and scattered. Therefore, it is not difficult to see that the organic peroxide cannot meet the demand of the domestic market in terms of both types and capacity.

[0004] Polyvinyl chloride is one of the largest general-purpose plastics in the world, which plays a wide role in the fields of pipeline, power, building and daily consumer goods due to its characteristics such as small weight, low cost, easy processing, good durability and strong flame retardance. In industry, polyvinyl chloride is synthesized by liquid phase with pressurized chloroethylene gas, and the initiator used is organic peroxide. Due to the toxicity of chloroethylene gas, liquid organic peroxide which is easy to feed in a closed reactor system has attracted more and more attention.

[0005] Di-(3,5,5-trimethylhexanoyl) peroxide, abbreviated as TMHP or initiator K, is a typical diacyl peroxide, which belongs to the category of low-temperature organic peroxide and is in liquid state at normal temperature and pressure. It is commonly used as an initiator for polymerization of vinyl monomers in industry, especially for producing high-grade polyvinyl chloride, which has the advantages of uniform polymerization reaction speed, easy control, uniform product particle size and few fish eyes. From the production process, currently such substances are mainly synthesized by batch stirred tank process, that is, hydrogen peroxide and 3,5,5-trimethylhexanoyl chloride are added dropwise in strong alkali solution, and are accompanied by subsequent processes such as water separation, washing, drying and formulation, etc. There are problems such as high risk of reaction heat, long feeding time and difficult process control, which is a typical dangerous process. Therefore, with the increasing attention of the society to environmental protection and safety production, it is an inevitable trend to develop new efficient and safe synthesis process and process equipment of organic peroxide.

[0006] Reference document 1 discloses a method for continuously preparing di-(3,5,5-trimethylhexanoyl) peroxide, which comprises preparing an alkaline aqueous solution, reacting the alkaline aqueous solution and hydrogen peroxide in a reactor, adding an isonitroso chloride solution to react with the product of the alkaline aqueous solution and hydrogen peroxide, and further fully reacting the product through a delay pipeline to obtain the product. However, the method is a secondary mixing process, and solid will be generated after the alkaline solution and the hydrogen peroxide solution are mixed, which will cause the blockage of the micro-reactor. Moreover, the isonitroso chloride used is not miscible with water, and the product of the reaction of isonitroso chloride and water is also difficult to be miscible with water. In addition, the entire reaction is basically completed in the 2# reactor, and then the delay pipeline is used to complete the full reaction, which requires a very long pipeline and is not economical.

[0007] Therefore, it is a technical problem to be solved to study a synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide and an equipment for implementing the synthesis method.

[0008] Reference document 1: CN104447471A SUMMARY

[0009] Problems to be solved by the invention

[0010] In view of the problems in the prior art, such as high thermal risk and low production efficiency, the present application first provides a synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide. The synthesis method is based on the whole process of micro-reaction continuous synthesis, and realizes safe and efficient conversion from raw materials to commercial products.

[0011] Further, the synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide of the present application also solves the problems of large holdup, poor heat exchange capacity and poor liquid-liquid dispersion effect of the existing production process and reaction equipment at home and abroad, and improves the efficiency and safety level of the peroxidation process, and fundamentally eliminates the hidden dangers.

[0012] Further, the present application also provides an equipment for implementing the synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide, which is simple and can ensure that the treatment method is carried out efficiently and orderly, and the heat risk of the equipment is low and the production efficiency is high.

[0013] Solution for solving the problem

[0014] [1] A synthesis method of di-(3,5,5-trimethylhexanoyl) peroxide, comprising the following steps:

[0015] The alkaline solution, the hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution are transported to the micro-mixer to be mixed, then enter the micro-reactor to be preliminarily reacted, and a first oil-water mixture is obtained;

[0016] The first oil-water mixture is transferred to a reaction vessel to continue the reaction, resulting in a second oil-water mixture.

[0017] The second oil-water mixture is subjected to a separation process to obtain the oil phase;

[0018] The oil phase was post-treated to obtain di-(3,5,5-trimethylhexanoyl peroxide).

[0019] [2] According to the synthesis method described in [1] above, the concentration of alkaline substance in the alkaline solution is 5 to 35 wt%; the concentration of hydrogen peroxide in the hydrogen peroxide solution is 20 to 80 wt%; and the concentration of 3,5,5-trimethylhexanoyl chloride in the 3,5,5-trimethylhexanoyl chloride solution is 20 to 100 wt%.

[0020] Preferably, the volume flow ratio of the alkaline solution to the 3,5,5-trimethylhexanoyl chloride solution is (0.35-6):1; and the volume flow ratio of the hydrogen peroxide solution to the 3,5,5-trimethylhexanoyl chloride solution is (0.05-1.2):1.

[0021] [3] According to the synthesis method described in [1] or [2] above, the temperature in the reactor is 0 to 45°C and the residence time in the reactor is 10 to 150 min.

[0022] [4] The synthesis method according to any one of [1]-[3] above, wherein the micro mixer is selected from a microchannel mixer, a membrane dispersion mixer or a microsieve mixer; and the microreactor is selected from a coil microreactor or a microchannel reactor.

[0023] [5] The synthesis method according to any one of [1]-[4] above, wherein the micromixer includes a first micromixer and a second micromixer, and the microreactor includes a first microreactor and a second microreactor; wherein,

[0024] The alkaline solution and hydrogen peroxide solution are mixed in the first micro mixer and then fed into the first microreactor for reaction to obtain an alkaline hydrogen peroxide solution.

[0025] After the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution are dispersed in a second micro mixer, they are introduced into a second microreactor for preliminary reaction to obtain the first oil-water mixture.

[0026] [6] The synthesis method according to any one of [1]-[5] above, wherein,

[0027] The temperature in the first micro mixer is 0–45°C, and the mixing time is greater than 0 and less than 10 seconds.

[0028] The temperature of the first microreactor is 0–45°C, and the residence time is 0.01–5 min.

[0029] The temperature in the second micro mixer is 0–50°C, and the mixing time is greater than 0 and less than 10 seconds.

[0030] The reaction temperature in the second microreactor is 0–50°C, and the residence time is 0.1–20 min.

[0031] [7] The synthesis method according to any one of [1]-[6] above, wherein the post-processing includes one or more of washing, drying and microporous membrane filtration;

[0032] Preferably, the washing is performed using a washing liquid; the drying is performed using a desiccant and / or a drying gas.

[0033] [8] The synthesis method according to any one of [7] above, wherein the washing solution is an aqueous solution of inorganic salt with a concentration of 0.1 to 10 wt%, preferably, the inorganic salt is selected from inorganic salts of alkali metals or alkaline earth metals;

[0034] The desiccant includes one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, or anhydrous calcium chloride; the drying gas is dry air or dry nitrogen, preferably, the temperature of the dry air is 0 to 30°C and the dew point is below -40°C.

[0035] The microporous filter membrane is made of an oleophilic and hydrophobic material, and the average pore size of the microporous filter membrane is 0.01 to 10 μm.

[0036] [9] The synthesis method according to any one of [1]-[8] above, wherein the synthesis method further includes the step of diluting the di-(3,5,5-trimethylhexanoyl peroxide) with a diluent; preferably, the diluent includes an oily solvent or an aqueous dispersion.

[0037]

[10] An apparatus for carrying out the synthesis method described in any one of [1]-[9] above, wherein the apparatus comprises a micro mixer, a microreactor, a reaction vessel and a separator connected in sequence;

[0038] Preferably, the micromixer includes a first micromixer and a second micromixer, and the microreactor includes a first microreactor and a second microreactor; wherein the first micromixer, the first microreactor, the second micromixer, and the second microreactor are connected in sequence.

[0039] More preferably, the distributor is further connected to one or more of the following: a washing distributor, a dryer, a microporous membrane filter, and a mixing tank.

[0040] The effects of the invention

[0041] The preparation of di-(3,5,5-trimethylhexanoyl) peroxide by micro-chemical processes centered on micro-mixers and microreactors can control local heat accumulation through rapid heat transfer, reduce the risk of combustion and explosion for thermally unstable organic peroxides, and increase the contact area between oil and water phases, thereby greatly improving production efficiency by increasing the reaction rate.

[0042] This invention utilizes a microreactor to prepare di-(3,5,5-trimethylhexanoyl) peroxide, which greatly reduces the feeding and reaction time, and improves the conversion efficiency from raw materials to commercial di-(3,5,5-trimethylhexanoyl) peroxide.

[0043] Furthermore, the di-(3,5,5-trimethylhexanoyl) peroxide product prepared by the synthesis method of the present invention has active oxygen content and other quality indicators that meet or exceed those of similar commercial products at home and abroad.

[0044] Furthermore, the equipment for the synthesis of di-(3,5,5-trimethylhexanoyl) peroxide of the present invention can ensure that the processing method is carried out efficiently and in an orderly manner, and the equipment has low thermal risk and high production efficiency. Attached Figure Description

[0045] Figure 1 A flowchart of an apparatus for synthesizing di-(3,5,5-trimethylhexanoyl) peroxide according to the present invention is shown.

[0046] Figure 2 A flowchart of an apparatus for synthesizing di-(3,5,5-trimethylhexanoyl) peroxide according to another method of the present invention is shown. Detailed Implementation

[0047] Various exemplary embodiments, features, and aspects of the present invention will be described in detail below. The term "exemplary" as used herein means "serving as an example, embodiment, or illustration." Any embodiment described herein as "exemplary" is not necessarily to be construed as superior to or better than other embodiments.

[0048] Furthermore, to better illustrate the present invention, numerous specific details are set forth in the following detailed embodiments. Those skilled in the art should understand that the present invention can be practiced without certain specific details. In other instances, methods, means, apparatus, and steps well known to those skilled in the art have not been described in detail in order to highlight the spirit of the present invention.

[0049] Unless otherwise stated, all units used in this specification are international standard units, and all numerical values ​​and ranges appearing in this invention should be understood to include systematic errors that are unavoidable in industrial production.

[0050] In this specification, the word "may" has two meanings: to perform a certain process and not to perform a certain process.

[0051] In this specification, references to "some specific / preferred embodiments," "other specific / preferred embodiments," "implementation," etc., refer to specific elements (e.g., features, structures, properties, and / or characteristics) related to that embodiment, which are included in at least one of the embodiments described herein and may or may not be present in other embodiments. Furthermore, it should be understood that these elements may be combined in any suitable manner in various embodiments.

[0052] In this specification, the range of values ​​referred to as "value A to value B" refers to the range including the endpoint values ​​A and B.

[0053] In this specification, the numerical range indicated by "above" or "below" refers to the numerical range that includes the stated number.

[0054] In this instruction manual, when "room temperature" or "room temperature" is used, the temperature can be 15-25℃.

[0055] <First aspect>

[0056] A first aspect of the present invention provides a method for synthesizing di-(3,5,5-trimethylhexanoyl) peroxide, comprising the following steps:

[0057] An alkaline solution, hydrogen peroxide solution, and 3,5,5-trimethylhexanoyl chloride solution are fed into a micro-mixer, mixed, and then fed into a microreactor for preliminary reaction to obtain a first oil-water mixture.

[0058] The first oil-water mixture is transferred to a reaction vessel to continue the reaction, resulting in a second oil-water mixture.

[0059] The second oil-water mixture is subjected to a separation process to obtain the oil phase;

[0060] The oil phase was post-treated to obtain di-(3,5,5-trimethylhexanoyl peroxide).

[0061] This invention involves mixing an alkaline solution, hydrogen peroxide solution, and 3,5,5-trimethylhexanoyl chloride (isononanoyl chloride) solution in a micromixer before introducing them into a microreactor for preliminary reaction. This allows for liquid-liquid mixing and / or liquid-liquid dispersion of the alkaline solution, hydrogen peroxide solution, and 3,5,5-trimethylhexanoyl chloride solution within the micromixer. Because the micromixer increases the contact surface area between the alkaline solution, hydrogen peroxide solution, and 3,5,5-trimethylhexanoyl chloride solution, the mixing and / or dispersion of the materials before the reaction is more uniform, which is beneficial for subsequent reactions. Specifically, a pump (e.g., a horizontal flow pump, diaphragm pump, magnetic pump, centrifugal pump, etc.) can be used to feed the raw materials into the micromixer.

[0062] In some specific embodiments, the concentration of the alkaline substance in the alkaline solution is 5-35 wt%, preferably 7.5-12.5 wt%, for example: 10 wt%, 15 wt%, 20 wt%, 25 wt%, 30 wt%, etc.; the concentration of hydrogen peroxide in the hydrogen peroxide solution is 20-80 wt%, preferably 30-50 wt%, for example: 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, etc.; the concentration of 3,5,5-trimethylhexanoyl chloride in the 3,5,5-trimethylhexanoyl chloride solution is 20-100 wt%, preferably 50-100 wt%, for example: 30 wt%, 40 wt%, 50 wt%, 60 wt%, 70 wt%, 80 wt%, 90 wt%, etc.; when the concentrations of the three reactants are within the above ranges, the reaction can proceed effectively.

[0063] In some specific embodiments, the volumetric flow rate ratio of the alkaline solution to the 3,5,5-trimethylhexanoyl chloride solution is (0.35–6):1, for example: 0.5:1, 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, etc.; the volumetric flow rate ratio of the hydrogen peroxide solution to the 3,5,5-trimethylhexanoyl chloride solution is (0.05–1.2):1, for example: 0.05:1, 0.08:1, 0.1:1, 0.15:1, 0.2:1, 0.5:1, 1:1, etc. By keeping the volumetric flow rate ratio of the alkaline substance and hydrogen peroxide relative to 3,5,5-trimethylhexanoyl chloride within the above ranges, the 3,5,5-trimethylhexanoyl chloride can be fully converted, and the conversion rate can be adjusted.

[0064] Furthermore, by adjusting the amount of inlet liquid in the micro-mixer, the volumetric flow rate ratio of the alkaline solution to the 3,5,5-trimethylhexanoyl chloride solution is made to be (0.35–6):1, and the volumetric flow rate ratio of the hydrogen peroxide solution to the 3,5,5-trimethylhexanoyl chloride solution is made to be (0.05–1.2):1.

[0065] Specifically, in this invention, the solvent for dissolving alkaline substances or hydrogen peroxide is not particularly limited and can be any feasible polar solvent in the art, preferably water. Similarly, the solvent for dissolving 3,5,5-trimethylhexanoyl chloride is not particularly limited and can be a commonly used oily solvent in the art, such as isododecane or solvent oil or a mixture thereof.

[0066] Furthermore, the present invention does not specifically limit the alkaline substance; it can be a commonly used strong alkaline substance in the art, such as sodium hydroxide or potassium hydroxide.

[0067] Furthermore, since the reaction rate gradually slows down in the later stages, complete material conversion within a microreactor would require a significantly larger reactor volume, such as the length of a coil, which is detrimental to process economy. Therefore, this invention also transfers the first oil-water mixture obtained from the initial reaction to a reaction vessel for further reaction to obtain a second oil-water mixture. Specifically, the reaction vessel is a non-microreactor, such as a batch stirred tank reactor.

[0068] By transferring the initial oil-water mixture obtained from the preliminary reaction to a reaction vessel for further reaction, 3,5,5-trimethylhexanoyl chloride can be completely converted. Specifically, in this invention, the temperature in the reaction vessel is 5–30°C, and the residence time in the reaction vessel is 10–150 min, for example: 30 min, 50 min, 80 min, 100 min, 120 min, etc. By continuing the reaction in the reaction vessel for 10–150 min, both complete conversion of the reactants and process efficiency can be achieved.

[0069] Specifically, this invention does not impose any particular limitation on the micromixer; it can be any micromixer known in the art suitable for liquid-liquid mixing, such as microchannel mixers, membrane dispersion mixers, or microsieve mixers. Similarly, this invention does not impose any particular limitation on the microreactor; it can be any microreactor known in the art suitable for homogeneous liquid reactions, such as coiled microreactors, micro-packed bed reactors, microchannel reactors, etc., with coiled microreactors being preferred, the diameter of the coil being 0.5–5 mm.

[0070] In this invention, when an alkaline solution, hydrogen peroxide solution, and 3,5,5-trimethylhexanoyl chloride solution are directly mixed in a micro mixer, a high-concentration alkaline solution is generally used, and the resulting mixture of the three substances is a colorless liquid containing a certain amount of solid and a small amount of bubbles.

[0071] In some specific embodiments, the micromixer includes a first micromixer and a second micromixer, and the microreactor includes a first microreactor and a second microreactor; wherein,

[0072] The alkaline solution and hydrogen peroxide solution are mixed in the first micro mixer and then fed into the first microreactor for reaction to obtain an alkaline hydrogen peroxide solution.

[0073] After the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution are dispersed in a second micro mixer, they are introduced into a second microreactor for preliminary reaction to obtain the first oil-water mixture.

[0074] This invention uses a first micro-mixer to mix an alkaline solution and a hydrogen peroxide solution. Because the internal size of the first micro-mixer is small enough, the alkaline solution and hydrogen peroxide solution can be thoroughly mixed upon contact. Specifically, a pump (e.g., a horizontal flow pump, diaphragm pump, magnetic pump, centrifugal pump, etc.) can be used to introduce the alkaline solution and hydrogen peroxide solution into the first micro-mixer. Furthermore, the ratio of the amount of alkaline solution to hydrogen peroxide solution can be adjusted by regulating the flow rate of the alkaline solution to the hydrogen peroxide solution into the first micro-mixer. Specifically, the mass flow rate ratio of the alkaline solution to the hydrogen peroxide solution can be (0.05–0.5):1, for example: 0.1:1, 0.2:1, 0.3:1, 0.4:1, etc.

[0075] In some specific implementations, the temperature in the first micro-mixer is 0–45°C, preferably 5–30°C, and more preferably 10–20°C, for example: 15°C, 25°C, 35°C, 40°C, etc. By controlling the temperature in the first micro-mixer at 0–45°C, especially at 5–30°C, alkaline hydrogen peroxide solution can be stably prepared, reducing or avoiding hydrogen peroxide decomposition. The mixing time in the first mixer is greater than 0 and less than 10 seconds, for example: 1 second, 3 seconds, 5 seconds, 7 seconds, 9 seconds, etc. By setting the mixing time to greater than 0 and less than 10 seconds, production efficiency can be considered while ensuring thorough mixing.

[0076] It should be noted that the first micro-mixer mainly mixes alkaline solution and hydrogen peroxide solution, but at the same time, a certain amount of sodium hydroxide and hydrogen peroxide will also undergo an acid-base reaction.

[0077] This invention utilizes a first microreactor to react an alkaline solution with a hydrogen peroxide solution. The reaction involves the deprotonation of hydrogen peroxide in the presence of an alkaline substance, generating an alkaline hydrogen peroxide solution.

[0078] In some specific embodiments, the temperature of the first microreactor is 0–45°C, preferably 5–30°C, and more preferably 10–20°C, for example: 15°C, 25°C, 35°C, 40°C, etc. By controlling the temperature of the first microreactor to 0–45°C, especially 5–30°C, alkaline hydrogen peroxide solution can be stably prepared, reducing or avoiding hydrogen peroxide decomposition. The residence time of the first microreactor is 0.01–5 min, preferably 0.1–0.5 min, for example: 0.2 min, 0.4 min, 0.6 min, 0.8 min, 1 min, 2 min, 3 min, 4 min, etc. By controlling the residence time in the first microreactor to 0.01–5 min, the equipment size and investment can be reduced while ensuring a stable and complete reaction.

[0079] In this invention, the alkaline hydrogen peroxide solution obtained after the reaction in the first microreactor is a clear, colorless, and transparent homogeneous liquid, which may contain a small number of bubbles.

[0080] Furthermore, this invention involves dispersing an alkaline hydrogen peroxide solution and a 3,5,5-trimethylhexanoyl chloride solution in a second micromixer, ensuring thorough mixing. In this invention, the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution are immiscible. When the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution are pre-mixed in the second micromixer, the small internal size of the micromixer results in a large specific surface area and strong shear force at the contact between the oil and water phases, allowing for immediate and effective dispersion of the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution after mixing in the second micromixer.

[0081] Specifically, a pump (e.g., a horizontal flow pump, diaphragm pump, magnetic pump, centrifugal pump, etc.) can be used to introduce alkaline hydrogen peroxide solution and 3,5,5-trimethylhexanoyl chloride solution into the second micromixer. Furthermore, the ratio of alkaline hydrogen peroxide solution to 3,5,5-trimethylhexanoyl chloride solution can be adjusted by regulating the flow rate of the alkaline hydrogen peroxide solution into the second micromixer. Specifically, the flow rate ratio of the alkaline solution to the hydrogen peroxide solution can be (0.5–5):1, for example: 0.8:1, 1:1, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, etc.

[0082] In some specific implementations, the temperature in the second micro-mixer is 0–50°C, preferably 20–30°C, for example: 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, etc. By controlling the temperature in the second micro-mixer to 0–50°C, good dispersion of the liquid-liquid two phases can be achieved, while reducing or avoiding hydrogen peroxide decomposition. The mixing time in the second micro-mixer is greater than 0 and less than 10 seconds, for example: 1 second, 3 seconds, 5 seconds, 7 seconds, 9 seconds, etc. By controlling the mixing time to be greater than 0 and less than 10 seconds, production efficiency can be considered while ensuring good dispersion.

[0083] It should be noted that the second micro-mixer mainly disperses the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution. However, a certain amount of 3,5,5-trimethylhexanoyl chloride also reacts with the substances contained in the aqueous phase. Therefore, a certain amount of di-(3,5,5-trimethylhexanoyl) peroxide will also be produced after mixing in the second micro-mixer.

[0084] This invention utilizes a second microreactor to initiate a preliminary reaction between an alkaline hydrogen peroxide solution and a 3,5,5-trimethylhexanoyl chloride solution, yielding a first oil-water mixture. The process involves the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution coming into contact in the oil-water two-phase mixture within the microreactor, resulting in a peroxidation reaction.

[0085] In some specific implementations, the reaction temperature in the second microreactor is 0–50°C, preferably 20–30°C, for example: 5°C, 10°C, 15°C, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, etc. By controlling the temperature of the second microreactor to 0–50°C, the reaction can proceed rapidly and stably while also taking into account the reactor's heat exchange capacity. The residence time in the second microreactor is 0.1–20 min, preferably 0.5–5 min, for example: 1 min, 2 min, 3 min, 4 min, 8 min, 10 min, 12 min, 15 min, 18 min, etc. By controlling the residence time in the second microreactor to 0.1–20 min, the equipment size and investment can be reduced while ensuring the highest possible reaction conversion rate.

[0086] Furthermore, the first micro-mixer and the second micro-mixer of the present invention may be the same or different, both being micro-mixers, which may be microchannel mixers, membrane dispersion mixers, or micro-sieve mixers, etc.; the first microreactor and the second microreactor of the present invention may be the same or different, both being microreactors, which may be coil-type microreactors, micro-packed bed reactors, microchannel reactors, etc.

[0087] The first oil-water mixture obtained after the reaction in the second microreactor can be separated into two liquid phases upon standing, both of which are transparent to milky white in appearance. By separating the aqueous phase, which does not contain di-(3,5,5-trimethylhexanoyl) peroxide, from the oil phase, an oil phase with high purity of di-(3,5,5-trimethylhexanoyl) peroxide can be obtained. To further obtain an oil phase with even lower impurity content, the oil phase after oil-water separation can be post-processed.

[0088] In some specific implementations, the post-processing includes one or more of washing, drying, and microporous membrane filtration.

[0089] The washing process involves using a washing solution to remove small amounts of residual acyl chlorides or other acidic substances or salt impurities from the oil phase, thereby obtaining a purer di-(3,5,5-trimethylhexanoyl) peroxide. During washing, the temperature can be controlled between 5 and 30°C, preferably between 15 and 25°C.

[0090] The present invention does not impose any particular limitation on the washing solution, and it can be any feasible washing solution in the art. Specifically, the washing solution is an inorganic salt aqueous solution with a concentration of 0-10 wt%, and the concentration of the inorganic salt aqueous solution can be 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 7 wt%, 9 wt%, etc. By using the washing solution to wash the oil phase, trace amounts of residual acyl chlorides or other acidic substances or salt impurities in the oil phase can be effectively washed away from the oil phase.

[0091] Furthermore, the volume ratio of the washing liquid to the oil phase being washed is 0.3 to 3:1, for example: 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1, etc.

[0092] Preferably, the inorganic salt is selected from inorganic salts of alkali metals or alkaline earth metals. For example, it can be one or a combination of two or more of alkali metal or alkaline earth metal halides, sulfates, carbonates, bicarbonates, nitrates, phosphates, etc. Preferably, the inorganic salt can be one or more of carbonates or bicarbonates selected from alkali metals, more preferably one or more of sodium carbonate, sodium bicarbonate, potassium carbonate, and potassium bicarbonate. In this invention, the washing solution can be used multiple times between multiple production batches.

[0093] Furthermore, after washing, oil-water separation can be performed to obtain the washed oil phase. Generally, the washing and oil-water separation process can be performed 0 to multiple times, where 0 times means this step is unnecessary, and 1 to 2 times is preferred. By controlling the number of washing cycles within the above range, efficiency can be considered while ensuring product quality as much as possible.

[0094] The pH value of the washed oil phase is 5-7, and the total content of inorganic chlorine and organic hydrolyzable chlorine in the washed oil phase is ≤500ppm, preferably ≤200ppm.

[0095] For drying, the drying is carried out using a desiccant and / or a drying gas. The present invention can remove water from the oil phase by drying. Preferably, the water is removed from the washed oil phase. This drying step can also be omitted when the water content in the oil phase is sufficiently low.

[0096] Specifically, the desiccant can be one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, or anhydrous calcium chloride. Drying is achieved by suspending the solid desiccant in the oil phase through stirring. The mass ratio of the desiccant to the oil phase being dried can be 0.001 to 1:1, for example: 0.005:1, 0.01:1, 0.03:1, 0.05:1, 0.08:1, etc. The drying time can be 0.01 to 2 hours, for example: 0.05 hours, 0.1 hours, 0.5 hours, 1 hour, 1.5 hours, etc.

[0097] The drying gas is dry air or dry nitrogen. Preferably, the temperature of the drying air is 0–30°C, for example: 5°C, 10°C, 15°C, 20°C, 25°C, etc.; and the dew point is below -40°C. Drying is achieved by blowing the gas into the oil phase, and the drying time is 0.01–2 hours, for example: 0.05 hours, 0.1 hours, 0.5 hours, 1 hour, 1.5 hours, etc.

[0098] For microporous membrane filtration, the present invention uses a microporous membrane to separate the aqueous phase and oil phase that do not contain di-(3,5,5-trimethylhexanoyl) peroxide, thereby obtaining an oil phase with high purity of di-(3,5,5-trimethylhexanoyl) peroxide.

[0099] The microporous membrane filtration method of the present invention can replace drying; for example, it can be used to filter the washed oil phase using a microporous membrane.

[0100] The present invention does not impose any particular limitation on the microporous filter membrane, and it can be selected according to the needs. Specifically, the microporous filter membrane can be made of oleophilic and hydrophobic materials, such as polytetrafluoroethylene, polyvinylidene fluoride, polypropylene, etc., with an average pore size of 0.01 to 10 μm.

[0101] Finally, the synthesis method further includes the step of diluting the di-(3,5,5-trimethylhexanoyl) peroxide using a diluent; preferably, the diluent comprises an oily solvent or an aqueous dispersion. For oily solvents, examples may be isododecane and / or solvent oil. For aqueous dispersions, examples may be one or a combination of two or more of water, methanol, ethanol, ethylene glycol, polyvinyl alcohol, and bleach. Preferably, the aqueous dispersion is a mixture of water and methanol.

[0102] The final oil phase is mixed with a diluent to obtain the di-(3,5,5-trimethylhexanoyl) peroxide product. This final oil phase can be a post-treatment phase or an oil phase that does not require post-treatment.

[0103] <Second aspect>

[0104] A second aspect of the present invention provides an apparatus for implementing the synthesis method described in the first aspect of the present invention, wherein the apparatus comprises a micromixer, a microreactor, a reaction vessel, and a separator connected in sequence.

[0105] In some specific embodiments, the micromixer includes a first micromixer and a second micromixer, and the microreactor includes a first microreactor and a second microreactor; wherein the first micromixer, the first microreactor, the second micromixer, and the second microreactor are connected in sequence.

[0106] Specifically, the distributor is further connected to one or more of the following: a washing distributor, a dryer, a microporous membrane filter, and a mixing tank.

[0107] By using the equipment of the present invention, the synthesis of di-(3,5,5-trimethylhexanoyl) peroxide of the present invention can be carried out efficiently and in an orderly manner, and the equipment has low thermal risk and high production efficiency.

[0108] Example

[0109] The embodiments of the present invention will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified in the examples, conventional conditions or conditions recommended by the manufacturer are followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0110] Example 1

[0111] The parameters of the microreactor used in the following examples are as follows:

[0112] Micro mixer No. 1 is a T-type micro tee mixer made of 316 stainless steel with a channel diameter of 0.50mm.

[0113] Micro mixer #2 is a T-type micro tee mixer made of 316 stainless steel with a channel diameter of 0.25mm.

[0114] Microreactor No. 1 is a coil-type microreactor made of 316 stainless steel, with an inner diameter of 2.175 mm and an adjustable length.

[0115] Microreactor No. 2 is a coil-type microreactor made of 316 stainless steel, with an inner diameter of 1.60 mm and an adjustable length.

[0116] The reactive oxygen species content described in the following examples was determined by iodometric titration, referring to the national standard GB / T32102-2015; the inorganic chlorine and organic hydrolyzable chlorine contents described in the following examples were determined by ion chromatography.

[0117] Example 1:

[0118] like Figure 1 As shown, 125.00 g of sodium hydroxide was dissolved in 875.00 g of water as feed solution A. Untreated 30 wt% hydrogen peroxide was used as feed solution B. Untreated 98 wt% 3,5,5-trimethylhexanoyl chloride was used as feed solution C. Feed solutions A and B were separately pumped into micromixer No. 1 using a horizontal flow pump. The mixer temperature was 20 °C, the mixing time was 1 s, the flow rate of feed solution A was 15.7 mL / min, and the flow rate of feed solution B was 3.240 mL / min. The resulting mixture entered microreactor No. 1, where the residence time in the reaction coil was 0.30 min, and the reaction coil temperature was 20 °C. The alkaline hydrogen peroxide solution obtained from the outlet of microreactor No. 1 was mixed with feed solution C pumped by the horizontal flow pump in micromixer No. 2 for liquid-liquid dispersion. The flow rate of feed solution C was 10.000 mL / min, and the mixing time was 0.5 s. The dispersed heterogeneous fluid was introduced into microreactor No. 2, where the temperature was controlled at 30°C and the residence time in the reaction coil was 2.80 min, yielding the first oil-water mixture. The discharge from microreactor No. 2 was then fed into a batch stirred tank for stirring for 30 min, resulting in the second oil-water mixture. The second oil-water mixture was separated, and the oil phase was washed with a 2 wt% sodium carbonate solution (volume ratio of 2 wt% sodium carbonate solution to oil phase was 1:1). Anhydrous magnesium sulfate was then added to the oil phase (mass ratio of anhydrous magnesium sulfate to oil phase was 0.05:1). The anhydrous magnesium sulfate was suspended in the oil phase by stirring and dried for 30 min. The solids were then separated from the oil phase by filtration. Analysis of the obtained oil phase showed an active oxygen content of 5.02% and an inorganic chlorine and organic hydrolyzable chlorine content of 182 ppm. Mixing isododecane with the oil phase at a mass ratio of 0.315:1 yields a 75% di-(3,5,5-trimethylhexanoyl) peroxide solvent-based product.

[0119] Example 2

[0120] like Figure 1As shown, 125.00 g of sodium hydroxide was dissolved in 875.00 g of water as feed solution A. Untreated 30 wt% hydrogen peroxide was used as feed solution B. Untreated 98 wt% 3,5,5-trimethylhexanoyl chloride was used as feed solution C. Feed solutions A and B were separately pumped into micromixer No. 1 using a horizontal flow pump. The mixer temperature was 10 °C, the mixing time was 1 s, the flow rate of feed solution A was 15.7 mL / min, and the flow rate of feed solution B was 3.240 mL / min. The resulting mixture entered microreactor No. 1, where the residence time in the reaction coil was 0.20 min, and the reaction coil temperature was 10 °C. The alkaline hydrogen peroxide solution obtained from the outlet of microreactor No. 1 was mixed with feed solution C pumped by the horizontal flow pump in micromixer No. 2 for liquid-liquid dispersion. The flow rate of feed solution C was 10.000 mL / min, and the mixing time was 0.5 s. The dispersed heterogeneous fluid was introduced into microreactor No. 2, where the temperature was controlled at 30°C and the residence time in the reaction coil was 3.50 min, yielding the first oil-water mixture. The discharge from microreactor No. 2 was then fed into a batch stirred tank for 20 min, resulting in the second oil-water mixture. The second oil-water mixture was separated, and the oil phase was washed with a 2 wt% sodium bicarbonate solution (volume ratio of 2 wt% sodium bicarbonate solution to oil phase was 0.8:1). Anhydrous sodium sulfate was then added to the oil phase (mass ratio of anhydrous sodium sulfate to oil phase was 0.05:1), and the sodium sulfate was suspended in the oil phase by stirring. The mixture was dried for 30 min, and the solids were separated from the oil phase by filtration. Analysis of the obtained oil phase showed an active oxygen content of 5.07% and an inorganic chlorine and organic hydrolyzable chlorine content of 143 ppm. A diluent is prepared by mixing water and methanol at a mass ratio of 1:1. The diluent is then mixed with the oil phase at a mass ratio of 0.993:1 to obtain a 50% di-(3,5,5-trimethylhexanoyl) peroxide emulsion product.

[0121] Example 3

[0122] like Figure 1As shown, 125.00 g of sodium hydroxide was dissolved in 875.00 g of water as feed solution A. Untreated 30 wt% hydrogen peroxide was used as feed solution B. Untreated 98 wt% 3,5,5-trimethylhexanoyl chloride was used as feed solution C. Feed solutions A and B were separately pumped into micromixer No. 1 using a horizontal flow pump. The mixer temperature was 20 °C, the mixing time was 1 s, the flow rate of feed solution A was 16.4 mL / min, and the flow rate of feed solution B was 2.970 mL / min. The resulting mixture entered microreactor No. 1, where the residence time in the reaction coil was 0.20 min, and the reaction coil temperature was 20 °C. The alkaline hydrogen peroxide solution obtained from the outlet of microreactor No. 1 was mixed with feed solution C pumped by the horizontal flow pump in micromixer No. 2 for liquid-liquid dispersion. The flow rate of feed solution C was 10.000 mL / min, and the mixing time was 0.5 s. The dispersed heterogeneous fluid was introduced into microreactor No. 2, where the temperature was controlled at 20°C and the residence time in the reaction coil was 2.80 min, yielding the first oil-water mixture. The discharge from microreactor No. 2 was then fed into a batch stirred tank for 45 min, resulting in the second oil-water mixture without washing. The second oil-water mixture was separated, and anhydrous sodium sulfate was added to the oil phase at a mass ratio of 0.08:1. The anhydrous sodium sulfate was suspended in the oil phase by stirring, and the mixture was dried for 45 min. The solids were then separated from the oil phase by filtration. Analysis of the obtained oil phase showed an active oxygen content of 5.06% and an inorganic chlorine and organic hydrolyzable chlorine content of 298 ppm. Mixing the solvent oil and the oil phase at a mass ratio of 0.987:1 yielded a 50% di-(3,5,5-trimethylhexanoyl) peroxide solvent-based product.

[0123] Example 4

[0124] like Figure 1As shown, 175.00 g of sodium hydroxide was dissolved in 825.00 g of water as feed solution A. Untreated 30 wt% hydrogen peroxide was used as feed solution B. Untreated 98 wt% 3,5,5-trimethylhexanoyl chloride was used as feed solution C. Feed solutions A, B, and C were separately pumped into micromixer No. 1 using a horizontal flow pump. The mixer temperature was 20°C, the mixing time was 0.5 s, the flow rate of feed solution A was 11.2 mL / min, the flow rate of feed solution B was 3.240 mL / min, and the flow rate of feed solution C was 10.000 mL / min. The mixed and dispersed heterogeneous fluids entered microreactor No. 1, where the temperature was controlled at 30°C and the residence time in the reaction coil was 3.50 min, resulting in the first oil-water mixture. The discharge from microreactor No. 1 was then fed into an intermittent stirred tank for stirring for 40 min, resulting in the second oil-water mixture after the conversion was completed. The second oil-water mixture was separated, and the oil phase was washed with a 1 wt% sodium bicarbonate solution (volume ratio of 1 wt% sodium bicarbonate solution to oil phase was 1:1). The oil phase was then separated. Anhydrous sodium sulfate was added to the oil phase (mass ratio of anhydrous sodium sulfate to oil phase was 0.05:1). The anhydrous sodium sulfate was suspended in the oil phase by stirring, and the mixture was dried for 30 minutes. The solids were then separated from the oil phase by filtration. Analysis of the obtained oil phase showed an active oxygen content of 5.07% and an inorganic chlorine and organic hydrolyzable chlorine content of 130 ppm. A diluent was prepared using a water-methanol mass ratio of 1:1. This diluent was mixed with the oil phase at a mass ratio of 0.993:1 to obtain a 50% di-(3,5,5-trimethylhexanoyl) peroxide emulsion product.

[0125] It should be noted that although the technical solution of the present invention has been described with specific examples, those skilled in the art will understand that the present invention should not be limited thereto.

[0126] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A method for synthesizing di-(3,5,5-trimethylhexanoyl) peroxide, characterized in that, Includes the following steps: An alkaline solution, hydrogen peroxide solution, and 3,5,5-trimethylhexanoyl chloride solution are fed into a micro mixer, mixed, and then fed into a microreactor for a preliminary reaction to obtain the first oil-water mixture. The first oil-water mixture is transferred to a reaction vessel to continue the reaction, resulting in a second oil-water mixture. The reaction vessel is a non-microreactor, the temperature in the reaction vessel is 0~45℃, and the residence time in the reaction vessel is 10~150min. The second oil-water mixture is subjected to a separation process to obtain the oil phase; The oil phase is post-treated to obtain di-(3,5,5-trimethylhexanoyl) peroxide. The post-treatment includes washing, which is performed using a washing solution, which is an aqueous solution of an inorganic salt with a concentration of 0.1~10 wt%. The total content of inorganic chlorine and organic hydrolyzable chlorine in the oil phase after washing is ≤500ppm; The micromixer includes a first micromixer and a second micromixer, and the microreactor includes a first microreactor and a second microreactor; wherein... The alkaline solution and hydrogen peroxide solution are mixed in the first micro mixer and then fed into the first microreactor for reaction to obtain an alkaline hydrogen peroxide solution. After the alkaline hydrogen peroxide solution and the 3,5,5-trimethylhexanoyl chloride solution are dispersed in a second micro mixer, they are introduced into a second microreactor for preliminary reaction to obtain the first oil-water mixture. The alkaline solution has a concentration of 5-35 wt% for the alkaline substance; the hydrogen peroxide solution has a concentration of 20-80 wt% for the hydrogen peroxide; and the 3,5,5-trimethylhexanoyl chloride solution has a concentration of 20-100 wt% for the 3,5,5-trimethylhexanoyl chloride. The temperature in the first micro-mixer is 0~45℃, and the mixing time is greater than 0 and less than 10 s; The temperature of the first microreactor is 0~45℃, and the residence time is 0.01~5 min; The temperature in the second micro-mixer is 0~50℃, and the mixing time is greater than 0 and less than 10 s; The reaction temperature in the second microreactor is 0~50℃, and the residence time is 0.1~20 min.

2. The synthesis method according to claim 1, characterized in that, The volumetric flow rate ratio of the alkaline solution to the 3,5,5-trimethylhexanoyl chloride solution is (0.35~6):1; the volumetric flow rate ratio of the hydrogen peroxide solution to the 3,5,5-trimethylhexanoyl chloride solution is (0.05~1.2):

1.

3. The synthesis method according to claim 1 or 2, characterized in that, The micromixer is selected from microchannel mixers, membrane dispersion mixers, or microsieve mixers; the microreactor is selected from coil microreactors or microchannel reactors.

4. The synthesis method according to claim 1 or 2, characterized in that, The post-processing includes one or both of drying and microporous membrane filtration.

5. The synthesis method according to claim 4, characterized in that, The drying process involves using a desiccant and / or a drying gas.

6. The synthesis method according to claim 5, characterized in that, The desiccant includes one or more of anhydrous magnesium sulfate, anhydrous sodium sulfate, or anhydrous calcium chloride; the drying gas is dry air or dry nitrogen. The microporous filter membrane is made of an oleophilic and hydrophobic material, and the average pore size of the microporous filter membrane is 0.01~10 μm.

7. The synthesis method according to claim 6, characterized in that, The inorganic salt is selected from inorganic salts of alkali metals or alkaline earth metals; The temperature of the dry air is 0~30℃, and the dew point is below -40℃.

8. The synthesis method according to claim 1 or 2, characterized in that, The synthesis method further includes the step of diluting the di-(3,5,5-trimethylhexanoyl) peroxide with a diluent.

9. The synthesis method according to claim 8, characterized in that, The diluent includes an oil-based solvent or an aqueous dispersion.

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