A method for preparing tert-butyl peroxide using a microchannel reactor

Abstract

This invention discloses a method for preparing tert-butyl benzoate peroxide using a microchannel reactor, comprising the following steps: adding liquid alkali to tert-butyl hydroperoxide, allowing it to stand and separate into layers, and obtaining the lower sodium salt; passing the obtained sodium salt into the microchannel reactor, simultaneously passing benzoyl chloride into the microchannel reactor for mixing and reaction; passing the material emanating from the microchannel reactor into an RTB reactor for incubation and reaction to obtain crude tert-butyl benzoate peroxide; purifying the crude tert-butyl benzoate peroxide to obtain tert-butyl benzoate peroxide. This invention employs continuous feeding and achieves the synthesis reaction through a microchannel reactor, reducing the reaction time from several hours to tens of seconds to several minutes, significantly improving reaction efficiency. The entire reaction process in the microchannel reactor used in this invention is a continuous reaction, which is safe and environmentally friendly, has high production efficiency, requires a small equipment footprint, is simple to operate, reduces manual operation, and lowers production costs.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis, and more specifically to a method for preparing tert-butyl peroxide using a microchannel reactor. Background Technology

[0002] tert-butyl peroxide (TBPB or CP-02) is a colorless to slightly yellow liquid with a mild aromatic odor. It is insoluble in water but soluble in organic solvents. In the polymerization of ethylene, styrene, propylene, vinyl acetate, diallyl phthalate, and isobutylene, tert-butyl peroxide is widely used as an initiator. In the curing of unsaturated polyesters, it is widely used in molding processes such as SMC, BMC, and DMC. It can also be combined with more reactive solvents such as MEPK, BPO, or TBPO to form two-component curing systems.

[0003] Currently, the most common process route is to use sulfuric acid or other acids as catalysts and hydrogen peroxide as oxidant to catalytically oxidize tert-butanol to prepare tert-butyl hydrogen peroxide, and then react it with an aqueous solution of alkali metal hydroxide (commonly sodium hydroxide or potassium hydroxide) and benzoyl chloride to synthesize tert-butyl benzoate peroxide.

[0004] Chinese patent CN1763001A discloses a production process for tert-butyl peroxide. After preparing a sodium salt, the sodium salt is added dropwise to benzoyl chloride, and the reaction is carried out under controlled temperature. The temperature is maintained after the addition, requiring 1-3 hours in total. This process is complex and has low production efficiency. Chinese patent CN105175303A discloses a preparation process for a tert-butyl peroxide initiator, which involves synthesis using hydrogen peroxide, sulfuric acid, tert-butanol peroxide, and benzoyl chloride. This process uses a variety of complex raw materials and is not suitable for industrial mass production.

[0005] Microchannel reactors possess a range of characteristics not found in conventional reactors: miniaturized channel size, large heat transfer surface area, excellent mass and heat transfer characteristics, continuous reaction, the ability to skip step-by-step scale-up tests and directly scale up, flexible production, and high safety performance.

[0006] Currently, there are no reports in this field on the synthesis of tert-butyl peroxide using a microchannel reactor. Therefore, providing a safe, environmentally friendly method for preparing tert-butyl peroxide using a microchannel reactor that can improve production efficiency and resource utilization is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a method for preparing tert-butyl benzoate peroxide using a microchannel reactor to meet various requirements in the industrial production of tert-butyl benzoate peroxide, and to obtain the finished product of tert-butyl benzoate peroxide simply, economically and efficiently.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A method for preparing tert-butyl peroxide using a microchannel reactor includes the following steps:

[0010] (1) Add liquid alkali to tert-butyl hydrogen peroxide, let stand to separate the layers, and separate the lower sodium salt;

[0011] (2) The obtained sodium salt is fed into the microchannel reactor at a flow rate of 200-500 L / h, and benzoyl chloride is fed into the microchannel reactor at a flow rate of 20-50 L / h to mix and react.

[0012] (3) The material from the outlet of the microchannel reactor was fed into the RTB reactor and kept at a constant temperature to obtain crude tert-butyl peroxide.

[0013] (4) The crude product of tert-butyl peroxide was purified to obtain tert-butyl peroxide.

[0014] Furthermore, the molar ratio of benzoyl chloride to tert-butyl hydroperoxide is 1:1.05-1.5.

[0015] The beneficial effects of adopting the above-mentioned further solutions are as follows:

[0016] By controlling the range of material molar ratios in the reaction as described above, the reaction becomes more complete and reduces the generation of side reactions. At the same time, it can also avoid excessive input of raw materials, which could leave residues in the product and affect the purity and quality of the subsequent target product.

[0017] Furthermore, the mixing reaction temperature in step (2) is 10-40℃ and the reaction time is 30-200s.

[0018] The beneficial effects of adopting the above-mentioned further solutions are as follows:

[0019] By controlling the temperature range in the reaction as described above, the reaction can proceed faster, increasing the reaction rate. It can also prevent the reaction temperature from being too high, which could cause the material to decompose at an accelerated rate, leading to combustion or explosion.

[0020] By controlling the reaction time range as described above, we can avoid incomplete reaction due to excessively short residence time, and avoid excessively long residence time, which can lead to slight decomposition of the product and low yield.

[0021] Furthermore, the heat preservation temperature in step (3) is 10-40℃, and the heat preservation reaction time is 10-30min.

[0022] The beneficial effects of adopting the above-mentioned further solutions are as follows: by controlling the temperature range during the heat preservation, the reaction can proceed faster, the reaction rate can be increased, and the reaction temperature can be prevented from being too high, which could cause the material to decompose at an accelerated rate, leading to combustion or explosion.

[0023] By controlling the time range during heat preservation as described above, we can avoid incomplete reaction due to excessively short residence time, and avoid excessively long residence time, which can lead to slight decomposition of the product and low yield.

[0024] Furthermore, the purification operation described in step (4) is as follows:

[0025] 1) The crude tert-butyl peroxide was added into the reactor and a dilute alkaline solution was added at a mass ratio of 1:1 (oil to water) for stirring and washing. The washing temperature was controlled at 10-40℃. After washing for 30-60 minutes, the mixture was allowed to stand and separate into layers. The oil layer was then taken for later use.

[0026] 2) The oil layer obtained in step 1) is added to the reactor, and sodium sulfide solution is added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature is controlled at 10-40℃. After washing for 30-60 minutes, the mixture is allowed to stand and separate into layers. The oil layer is then taken for later use.

[0027] 3) The oil layer obtained in step 2) is added to the reactor and water is added at a mass ratio of 1:1 for stirring and washing. The temperature during washing is controlled at 10-40℃. After washing for 30-60 minutes, the mixture is allowed to stand and separate into layers. The resulting oil layer is dried with a desiccant to obtain tert-butyl peroxide.

[0028] Furthermore, the dilute alkaline solution mentioned in step 1) is a sodium hydroxide solution with a mass concentration of 2-10%.

[0029] Furthermore, the mass concentration of the sodium sulfide solution in step 2) is 1-3%.

[0030] The beneficial effects of adopting the above-mentioned further solution are as follows: the present invention purifies the crude TBPB obtained by synthesis, reduces impurities in the product, improves product quality, and is beneficial to related downstream applications.

[0031] The beneficial effects of this invention are as follows:

[0032] 1. This invention uses continuous feeding and a microchannel reactor to achieve the synthesis reaction, which reduces the reaction time from several hours to tens of seconds to several minutes, significantly improving the reaction efficiency.

[0033] 2. The microchannel reactor used in this invention can enhance mass and heat transfer performance, maintain a constant reaction temperature, avoid temperature jumps, reduce the occurrence of side reactions, and improve the safety of the reaction process.

[0034] 3. In the present invention, the reactants are precisely added by a feed pump to avoid the increase of side reactions caused by inaccurate local chemical stoichiometry, which leads to a decrease in yield.

[0035] 4. The entire reaction process in the microchannel reactor used in this invention is a continuous reaction, which is safe and environmentally friendly, has high production efficiency, small equipment footprint, and simple operation. It can reduce manual operation, lower production costs, and ensure economic efficiency.

[0036] 5. The method of the present invention significantly improves the reaction yield, reaching 90-95%, and the purity of the final post-processed product reaches 99.0-99.5%. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] A method for preparing tert-butyl peroxide using a microchannel reactor includes the following steps:

[0040] (1) Add liquid alkali to tert-butyl hydrogen peroxide, let stand to separate the layers, and separate the lower sodium salt;

[0041] (2) After the microchannel reactor is preheated to 15°C, the obtained sodium salt is introduced into the microchannel reactor at a flow rate of 220 L / h, and benzoyl chloride is introduced into the microchannel reactor at a flow rate of 20 L / h. The flow rates of the two materials are kept constant at the set flow rate, which is the steady state. The materials are mixed in the steady state and reacted at 15°C for 30 s. The molar ratio of benzoyl chloride to tert-butyl hydroperoxide is 1:1.08.

[0042] (3) Pass the material from the outlet of the microchannel reactor into the RTB reactor and keep it at 15°C for 10 min to obtain crude tert-butyl peroxide.

[0043] (4) The crude tert-butyl peroxide was purified by the following steps:

[0044] 1) The crude tert-butyl peroxide was added into the reactor and 10% sodium hydroxide solution was added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature was controlled at 40℃. After washing for 30 minutes, the mixture was allowed to stand and separate into layers. The oil layer was then taken for later use.

[0045] 2) The oil layer obtained in step 1) is added to the reactor, and 1% sodium sulfide solution is added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature is controlled at 140℃. After washing for 30 minutes, the oil layer is allowed to stand and separate into layers. The oil layer is then taken for later use.

[0046] 3) The oil layer obtained in step 2) was added to the reactor and water was added at a mass ratio of 1:1 for stirring and washing. The washing temperature was controlled at 140℃. After washing for 30 minutes, the mixture was allowed to stand and separate into layers. The oil layer was dried with a desiccant to obtain tert-butyl benzoate. The reaction yield was measured to be 90.8%, and the TBPB product content was 99.3%.

[0047] Example 2

[0048] A method for preparing tert-butyl peroxide using a microchannel reactor includes the following steps:

[0049] (1) Add liquid alkali to tert-butyl hydrogen peroxide, let stand to separate the layers, and separate the lower sodium salt;

[0050] (2) After the microchannel reactor is preheated to 20°C, the obtained sodium salt is introduced into the microchannel reactor at a flow rate of 280 L / h, and benzoyl chloride is introduced into the microchannel reactor at a flow rate of 30 L / h. The flow rates of the two materials are kept constant at the set flow rates, which is the stable state. The materials are mixed in the stable state and reacted at 20°C for 60 s. The molar ratio of benzoyl chloride to tert-butyl hydroperoxide is 1:1.06.

[0051] (3) Pass the material from the outlet of the microchannel reactor into the RTB reactor and keep it at 20°C for 20 min to obtain crude tert-butyl peroxide.

[0052] (4) The crude tert-butyl peroxide was purified by the following steps:

[0053] 1) The crude tert-butyl peroxide was added into the reactor and 2% sodium hydroxide solution was added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature was controlled at 10℃. After washing for 60 minutes, the mixture was allowed to stand and separate into layers. The oil layer was then taken for later use.

[0054] 2) The oil layer obtained in step 1) is added to the reactor, and 3% sodium sulfide solution is added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature is controlled at 10℃. After washing for 60 minutes, the layers are allowed to stand and separate. The oil layer is then taken for later use.

[0055] 3) The oil layer obtained in step 2) was added to the reactor and water was added at a mass ratio of 1:1 for stirring and washing. The washing temperature was controlled at 10°C. After washing for 60 minutes, the mixture was allowed to stand and separate into layers. The oil layer was dried with a desiccant to obtain tert-butyl benzoate. The reaction yield was measured to be 92.3%, and the TBPB product content was 99.1%.

[0056] Example 3

[0057] A method for preparing tert-butyl peroxide using a microchannel reactor includes the following steps:

[0058] (1) Add liquid alkali to tert-butyl hydrogen peroxide, let stand to separate the layers, and separate the lower sodium salt;

[0059] (2) After the microchannel reactor is preheated to 35°C, the obtained sodium salt is introduced into the microchannel reactor at a flow rate of 360 L / h, and benzoyl chloride is introduced into the microchannel reactor at a flow rate of 40 L / h. The flow rates of the two materials are kept constant at the set flow rates, which is the stable state. The materials are mixed in the stable state and reacted at 35°C for 120 s. The molar ratio of benzoyl chloride to tert-butyl hydroperoxide is 1:1.05.

[0060] (3) Pass the material from the outlet of the microchannel reactor into the RTB reactor and keep it at 35°C for 30 min to obtain crude tert-butyl peroxide.

[0061] (4) The crude tert-butyl peroxide was purified by the following steps:

[0062] 1) The crude tert-butyl peroxide was added into the reactor and 6% sodium hydroxide solution was added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature was controlled at 25℃. After washing for 40 minutes, the mixture was allowed to stand and separate into layers. The oil layer was then taken for later use.

[0063] 2) The oil layer obtained in step 1) is added to the reactor, and 2% sodium sulfide solution is added at an oil-water mass ratio of 1:1 for stirring and washing. The washing temperature is controlled at 25℃. After washing for 40 minutes, the layers are allowed to stand and separate. The oil layer is then taken for later use.

[0064] 3) The oil layer obtained in step 2) was added to the reactor and water was added at a mass ratio of 1:1 for stirring and washing. The washing temperature was controlled at 25°C. After washing for 40 minutes, the mixture was allowed to stand and separate into layers. The oil layer was dried with a desiccant to obtain tert-butyl benzoate. The reaction yield was measured to be 94.1%, and the TBPB product content was 99.5%.

[0065] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A process for the preparation of t-butyl peroxybenzoate with a microchannel reactor, characterized in that, The method comprises the following steps: (1) adding liquid alkali into t-butyl hydroperoxide, standing and separating the lower sodium salt; (2) feeding the obtained sodium salt into a micro-channel reactor at a flow rate of 200-500 L / h, and feeding benzoyl chloride into the micro-channel reactor at a flow rate of 20-50 L / h to mix and react; The molar ratio of benzoyl chloride to t-butyl hydroperoxide is 1:1.05-1.5; The mixing reaction temperature is 10-40℃, and the reaction time is 30-200s; (3) feeding the material at the outlet of the micro-channel reactor into an RTB reactor for heat preservation reaction to obtain crude t-butyl perbenzoate; The heat preservation temperature is 10-40℃, and the heat preservation reaction time is 10-30min; (4) purifying the crude t-butyl perbenzoate, and the purification operation is as follows: 1) feeding the obtained crude t-butyl perbenzoate into a reaction kettle, and stirring and washing with a dilute alkali solution at an oil-water mass ratio of 1:1, controlling the temperature during washing to be 10-40℃, and standing and separating after washing for 30-60min, and taking the oil layer for standby use; the dilute alkali solution is a sodium hydroxide solution with a mass concentration of 2-10%; 2) continuously feeding the oil layer obtained in step 1) into the reaction kettle, and stirring and washing with a sodium sulfide solution at an oil-water mass ratio of 1:1, controlling the temperature during washing to be 10-40℃, and standing and separating after washing for 30-60min, and taking the oil layer for standby use; the mass concentration of the sodium sulfide solution is 1-3%; 3) continuously feeding the oil layer obtained in step 2) into the reaction kettle, and stirring and washing with water at an oil-water mass ratio of 1:1, controlling the temperature during washing to be 10-40℃, and standing and separating after washing for 30-60min, and drying the obtained oil layer with a drying agent to obtain t-butyl perbenzoate.