A process for the preparation of dibenzoyl peroxide

Abstract

The application discloses a preparation method of dibenzoyl peroxide, and relates to the technical field of organic peroxide preparation. The preparation method comprises the following steps: preparing dibenzoyl peroxide crude product and initial synthesis obtained recycling mother liquor; taking out two parts from the initial synthesis obtained recycling mother liquor, and reacting with a sodium hydroxide solution, hydrogen peroxide, a surfactant aqueous solution and benzoyl chloride; at least the benzoyl chloride is contained in the multiple materials, and the multiple materials are pre-mixed by a pre-mixer; heat preservation reaction is carried out, and after the reaction is completed, centrifugal separation is carried out to obtain the dibenzoyl peroxide crude product and second synthesis obtained recycling mother liquor; and the dibenzoyl peroxide crude product is sequentially subjected to water washing and solid-liquid separation to obtain a finished product. The pre-mixer is used to realize instant super-uniform mixing of the materials, the reaction is more uniform, the product is fine and small in particle size, the particle size distribution is uniform, the reaction yield is high, the amount of water used for subsequent washing is reduced, the recycling of the mother liquor reduces the discharge amount of high-salinity organic waste liquid from the source, and the preparation cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of organic peroxide preparation technology, specifically to a method for preparing benzoyl peroxide. Background Technology

[0002] Benzoyl peroxide, also known as benzoyl peroxide (BPO), is a white crystalline powder at room temperature with a slightly bitter almond odor. It is soluble in benzene, chloroform, and ether, and slightly soluble in ethanol and water. As a widely used diacyl organic peroxide, BPO can be used as a solvent polymer for polyacrylonitrile, acrylates, and vinyl acetate; as a graft polymer for chloroprene rubber, SBS, and methyl methacrylate; and as an initiator and crosslinking agent for plexiglass adhesives. BPO is also used in the rubber industry as a vulcanizing agent and crosslinking agent for silicone rubber and fluororubber, and in chemical production as a bleaching agent and oxidizing agent.

[0003] With industrial development, benzoyl peroxide is increasingly widely used in production, and the demand is growing. Currently, the main industrial method for its production is as follows: hydrogen peroxide is added to a sodium hydroxide solution under cooling conditions to generate an aqueous sodium peroxide solution; then benzoyl chloride is added dropwise under stirring, causing benzoyl peroxide to precipitate; the crude product is then filtered and washed to obtain the benzoyl peroxide product. This method has the following significant drawbacks: the large amount of mother liquor generated puts enormous pressure on the wastewater treatment system; the benzoyl peroxide product produced by this method has relatively large and unevenly sized particles (containing a small amount of dust-like benzoyl peroxide), posing a significant production risk; and the washing water consumption in the crude product post-processing is substantial.

[0004] Therefore, how to develop an efficient, safe, and environmentally friendly method for preparing benzoyl peroxide is a technical problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0005] In view of this, the present invention provides a method for intercropping sweet potatoes with flue-cured tobacco in order to reduce black shank disease in tobacco fields.

[0006] A method for preparing benzoyl peroxide includes the following steps:

[0007] (1) Add water to the first reaction vessel and begin stirring and cooling; (2) Sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are simultaneously fed into the first reactor through a high-level tank or self-priming pump. After feeding, the reaction is kept at a constant temperature. After the reaction in the first reactor is completed, the reactants are centrifuged to obtain crude benzoyl peroxide and the mother liquor obtained from the initial synthesis. (3) The crude benzoyl peroxide from step (2) is washed with water and separated into solid and liquid components to obtain the finished benzoyl peroxide product; (4) Take out two or three parts of the recycled mother liquor obtained from the initial synthesis, add the first part of the recycled mother liquor obtained from the initial synthesis into the first reaction vessel, and start stirring and cooling; (5) When two parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the second part of the recycled mother liquor obtained from the initial synthesis, sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are simultaneously fed into the first reactor through a high-level tank or self-priming pump. Before feeding, multiple materials containing at least benzoyl chloride are premixed through a premixer. After feeding, the reaction is kept at a constant temperature. After the reaction in the first reactor is completed, the crude benzoyl peroxide and the recycled mother liquor obtained from the second synthesis are obtained by centrifugation. Alternatively, when three parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the recycled mother liquor obtained from the initial synthesis in the second part, sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are simultaneously fed into the first reactor through a high-level tank or self-priming pump. Before feeding, multiple materials containing at least benzoyl chloride are pre-mixed by a premixer. After the initial reaction raw materials are fed, the first reactor is kept warm to react and obtain the initial reaction product of benzoyl peroxide. The recycled mother liquor obtained from the initial synthesis in the third part, sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are continuously fed into the first reactor. At the same time, the first reactor is kept warm to react. The initial reaction product containing benzoyl peroxide in the first reactor begins to overflow into the second reactor connected in series with the first reactor. When the second reactor reaches the stirring liquid level, the stirrer of the second reactor is turned on to continue stirring the reaction. After the reaction is completed, the reaction liquids of the two reactors are combined and centrifuged to obtain crude benzoyl peroxide and the recycled mother liquor obtained from the second synthesis. The material premixing process can be selected from the following three methods: ①The recycled mother liquor, surfactant aqueous solution and benzoyl chloride obtained from the initial synthesis in the second part are fed into the feed after being treated by a premixer. Hydrogen peroxide and sodium hydroxide solution are fed directly into the feed at the same time through a high-level tank or a self-priming pump. ②The recycled mother liquor, surfactant aqueous solution, benzoyl chloride and hydrogen peroxide obtained from the initial synthesis in the second part are fed into the feed after being treated by a premixer, while sodium hydroxide solution is fed directly into the feed through a high-level tank or a self-priming pump at the same time. ③The recycled mother liquor, surfactant aqueous solution, benzoyl chloride, hydrogen peroxide and sodium hydroxide solution obtained from the initial synthesis in Part 2 are fed into the feed after being treated by a premixer.

[0008] (6) The crude benzoyl peroxide from step (5) is washed with water and separated into solid and liquid components to obtain the finished benzoyl peroxide product; Furthermore, the production method of this invention is either intermittent production or continuous production.

[0009] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: Maintaining stable process parameters not only significantly improves production efficiency but also ensures the stability and uniformity of product quality.

[0010] Further, in step (1) or step (4), stirring and cooling begin, with a stirring speed of 300-600 rpm and a cooling temperature of 5-15℃.

[0011] Furthermore, the recycled mother liquor obtained from the initial synthesis or the recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: 18-25% sodium chloride, 0.4-0.6% sodium hydroxide, 0.2-0.4% hydrogen peroxide, 1-5% sodium benzoate, 0.01-0.1% sodium peroxybenzoate, and the balance being water; in step (2) or step (5), the concentration of sodium hydroxide solution is 20-32 wt%, the concentration of surfactant aqueous solution is 2 wt%, and the concentration of hydrogen peroxide is 27.5-35 wt%.

[0012] Furthermore, in step (2) or step (5), the molar ratio of benzoyl chloride, sodium hydroxide, and hydrogen peroxide in hydrogen peroxide is 1:(1.05-1.4):(0.6-0.8). In step (2), the weight ratio of the surfactant aqueous solution to hydrogen peroxide is (0.001-0.01):1; In step (5), when two parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the weight ratio of the recycled mother liquor obtained from the initial synthesis, the surfactant aqueous solution and the hydrogen peroxide in the second part is (10-40):(0.001-0.01):1; In step (5), when three parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the total amount of the recycled mother liquor obtained from the initial synthesis in the second part and the recycled mother liquor obtained from the initial synthesis in the third part, the weight ratio of the surfactant aqueous solution and hydrogen peroxide is (10-40):(0.001-0.01):1.

[0013] The beneficial effects of adopting the above-mentioned further technical solutions are: further optimizing the feeding ratio of reactants, so that the reaction ratio reaches the optimal range of the process, and improving the conversion rate of the main reaction and the product yield.

[0014] Furthermore, the surfactant in step (2) or step (5) is any one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, or sodium dodecyl sulfonate.

[0015] The beneficial effects of adopting the above-mentioned further technical solutions are: selecting suitable surfactants to enhance the contact between the two phases through emulsification, dispersion and solubilization, thereby improving the stability of the reaction.

[0016] Furthermore, in step (2), the heat preservation reaction temperature is 5-15℃, and the heat preservation reaction time is 20-60min; In step (5), the stirring speed of the premixer is 600-1000 rpm, and the premixing time is 0.5-1 s; In step (5), when two parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the reaction is kept warm after the feeding is completed. After the reaction in the first reactor is completed, crude benzoyl peroxide and recycled mother liquor obtained from the second synthesis are separated. The temperature of the warm reaction is 5-15℃ and the reaction time is 20-60min. Alternatively, in step (5), when three parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), after the initial reaction raw materials are fed in, the first reactor is kept at a constant temperature for 40-60 minutes and 8-15°C to obtain the initial reaction product of benzoyl peroxide; the first reactor is fed in continuously for the second time, while the first reactor is kept at a constant temperature of 8-15°C. The initial reaction product containing benzoyl peroxide in the first reactor begins to overflow into the second reactor connected in series with the first reactor. After the initial reaction product containing benzoyl peroxide in the first reactor overflows into the second reactor connected in series with the first reactor, the stirrer of the second reactor is turned on when the stirring liquid level is reached. The total time for the second continuous feeding into the first reactor and the stirring reaction in the second reactor is 50-80 minutes and the reaction temperature is 8-15°C. After the reaction is completed, the reaction liquids of the two reactors are combined and centrifuged to obtain crude benzoyl peroxide and the recycled mother liquor obtained from the second synthesis.

[0017] The beneficial effect of adopting the above-mentioned further technical solution is that it can effectively disperse multiple materials in a short time.

[0018] Furthermore, in step (2) or step (5), the centrifugation speed is 600-1200 rpm and the centrifugation time is 10-20 min.

[0019] Further, the feature is that in step (3) or step (6), crude benzoyl peroxide is added to a rinsing tank and washed continuously with water, and then sent to a centrifuge by a conveying device for centrifugal separation, that is, solid-liquid separation is performed to obtain the finished benzoyl peroxide product. The centrifugation speed is 600-1200 rpm and the centrifugation time is 10-20 min.

[0020] The beneficial effects of adopting the above-mentioned further technical solution are: secondary washing and refining of crude benzoyl peroxide (BPO) effectively reduces its residual impurity content, enhances the stability of product storage and application, and improves the uniformity of product quality.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects: The method provided by this invention uses the synthesized mother liquor, sodium hydroxide solution, hydrogen peroxide, surfactant, and benzoyl chloride as raw materials. A premixer achieves instantaneous ultra-uniform mixing of the materials, resulting in a more uniform reaction and a product with fine particles, uniform particle size distribution, and high reaction yield. It also effectively reduces the amount of water used for subsequent washing; the washing water usage in this application is 70%-90% of that in traditional methods. Simultaneously, by recycling the mother liquor, the discharge of high-salinity organic wastewater is significantly reduced at the source, greatly alleviating wastewater treatment pressure and environmental burden, and lowering preparation costs. Detailed Implementation

[0022] 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.

[0023] The preparation methods of the recycled mother liquor obtained from the initial synthesis in Examples 1-5 and Comparative Examples 1-2 include the following steps: (1) Add 3200 kg of process water to the first reactor, start stirring and cooling, with a stirring speed of 400 rpm and a cooling temperature of 10℃; (2) 220 kg of 32 wt% sodium hydroxide solution, 90 kg of 35 wt% hydrogen peroxide, 0.8 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor through a high-level tank. Sodium dodecylbenzenesulfonate aqueous solution (feeding rate 0.89 kg / h), benzoyl chloride (200 kg / h), hydrogen peroxide (100 kg / h), and sodium hydroxide solution (244 kg / h) were simultaneously fed directly through the high-level tank. After feeding, the reaction was kept at 12°C for 50 min. After the reaction, 182.7 kg of crude benzoyl peroxide and 3508.1 kg of the initial synthesis recycled mother liquor were obtained by centrifugation. The centrifugation speed was 900 rpm and the centrifugation time was 11 min. (3) The initial synthesis of the recycled mother liquor contains the following components by mass percentage: sodium chloride 22.3%, sodium hydroxide 0.5%, hydrogen peroxide 0.3%, sodium benzoate 4.0%, sodium peroxide 0.06%, and the remainder is water; (4) Add the crude benzoyl peroxide from step (2) into a rinsing tank and wash continuously with water (the amount of water used is 80% of that used in the traditional method). Then, send it to a centrifuge for centrifugation to separate the solid and liquid components and obtain 191.8 kg of benzoyl peroxide product (content 74.5%). The centrifugation speed is 900 rpm and the centrifugation time is 11 min. The yield of benzoyl chloride is 92.7%.

[0024] Example 1 The preparation method of benzoyl peroxide includes the following steps: (1) Add 2600 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 350 rpm and a cooling temperature of 9℃; (2) 760 kg of the initial synthesis recycled mother liquor, 163 kg of 32 wt% sodium hydroxide solution, 60 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor via a high-level tank. The initial synthesis recycled mother liquor (844 kg / h), sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), and benzoyl chloride (200 kg / h) were fed after being treated by a premixer. Hydrogen peroxide (67 kg / h) and sodium hydroxide solution (181 kg / h) were added. Simultaneously, the material was directly fed through a high-level tank at a rate of kg / h. The stirring speed of the premixer was 800 rpm, and the premixing time was 0.86 s. After feeding, the reaction was kept at 10℃ for 45 min. After the reaction, 187.1 kg of crude benzoyl peroxide and 3576.4 kg of recycled mother liquor from the second synthesis were obtained by centrifugation at a speed of 800 rpm for 13 min. The recycled mother liquor obtained from the second synthesis comprises, by mass percentage, the following components: sodium chloride 21.8%, sodium hydroxide 0.5%, hydrogen peroxide 0.3%, sodium benzoate 3.2%, sodium benzoate peroxide 0.06%, and the balance being water; (3) Add the crude benzoyl peroxide from step (2) into a rinsing vessel and wash continuously with water (the amount of water used is 80% of that used in the traditional method). Then, send it to a centrifuge by a conveying device for centrifugation to separate the solid and liquid components and obtain 196.6 kg of benzoyl peroxide product (content 74.6%). The centrifugation speed is 800 rpm and the centrifugation time is 13 min. The yield of benzoyl chloride is 95.1%.

[0025] Example 2 The preparation method of benzoyl peroxide includes the following steps: (1) Add 2700 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 500 rpm and a cooling temperature of 10℃; (2) 660 kg of the initial synthesis recycled mother liquor, 165 kg of 32 wt% sodium hydroxide solution, 68 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor via a high-level tank. The initial synthesis recycled mother liquor (733 kg / h), sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), benzoyl chloride (200 kg / h), and hydrogen peroxide (76 kg / h) were fed into the reactor after being treated by a premixer. The sodium hydroxide solution (183 kg / h) was added... The feed was fed directly through a high-level tank at a rate of kg / h. The stirring speed of the premixer was 800 rpm and the premixing time was 0.8 s. After feeding, the reaction was kept at 11 ℃ for 50 min. After the reaction, 189 kg of crude benzoyl peroxide and 3584.5 kg of recycled mother liquor from the second synthesis were obtained by centrifugation at a speed of 1000 rpm for 12 min. The recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: sodium chloride 21.3%, sodium hydroxide 0.52%, hydrogen peroxide 0.28%, sodium benzoate 3%, sodium peroxide 0.03%, and the balance being water; (3) Add the crude benzoyl peroxide from step (2) into a rinsing vessel and wash continuously with water (the amount of water used is 75% of that used in the traditional method). Then, send it to a centrifuge by a conveying device for centrifugation to separate the solid and liquid components and obtain 196.2 kg of benzoyl peroxide product (content 75.1%). The centrifugation speed is 1000 rpm and the centrifugation time is 12 min. The yield of benzoyl chloride is 95.6%.

[0026] Example 3 The preparation method of benzoyl peroxide includes the following steps: (1) Add 2400 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 400 rpm and a cooling temperature of 7℃; (2) 960 kg of the initial synthesis recycled mother liquor, 165 kg of 32 wt% sodium hydroxide solution, 50 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor through a high-level tank. The initial synthesis recycled mother liquor (1067 kg / h), sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), benzoyl chloride (200 kg / h), hydrogen peroxide (56 kg / h), and sodium hydroxide solution (183 kg / h) were then fed into the first reactor. After being processed by a premixer, the feed (kg / h) was fed into the premixer at a stirring speed of 800 rpm for 1 second. After feeding, the feed was kept at 15°C for 30 min. After the reaction, 188.3 kg of crude benzoyl peroxide and 3567.2 kg of recycled mother liquor from the second synthesis were obtained by centrifugation at a speed of 700 rpm for 18 min. The recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: sodium chloride 20.87%, sodium hydroxide 0.49%, hydrogen peroxide 0.32%, sodium benzoate 4.1%, sodium peroxide benzoate 0.06%, and the balance being water; (3) Add the crude benzoyl peroxide from step (2) into a rinsing vessel and wash continuously with water (the water volume is 90% of that of the traditional method). Then, send it to a centrifuge by a conveying device for centrifugation to separate solid and liquid and obtain 201.3 kg of benzoyl peroxide product (content 74.2%). The centrifugation speed is 700 rpm and the centrifugation time is 18 min. The yield of benzoyl chloride is 96.9%.

[0027] Example 4 The preparation method of benzoyl peroxide includes the following steps: (1) Add 2700 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 500 rpm and a cooling temperature of 10℃; (2) 660 kg of the initial synthesis recycled mother liquor, 150 kg of 32 wt% sodium hydroxide solution, 60 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor by a self-priming pump. The initial synthesis recycled mother liquor (733 kg / h), sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), and benzoyl chloride (200 kg / h) were fed after being treated by a premixer. Hydrogen peroxide (67 kg / h) and sodium hydroxide solution (167 kg / h) were fed directly by a self-priming pump. The stirring speed of the premixer was 800 rpm and the premixing time was 0.8 s. After feeding (continuous feeding for 54 min), the reaction was kept at 11 °C for 50 min to obtain the initial reaction product of benzoyl peroxide. (3) Continue to feed the first reactor at the feeding rate of step (2) for 60 minutes. At the same time, the first reactor is kept at 11°C for reaction. The initial reaction product begins to overflow into the second reactor connected in series with the first reactor. When the second reactor reaches the stirring level, start stirring at 450 rpm. The recycled mother liquor (2600 kg / h), sodium dodecylbenzenesulfonate aqueous solution (1.5 kg / h), and benzoyl chloride (480 kg / h) obtained from the initial synthesis are fed after being treated by the premixer. Hydrogen peroxide (210 kg / h) and sodium hydroxide solution (435 kg / h) are fed directly through the self-priming pump at the same time. The stirring speed of the premixer is 800 rpm and the premixing time is 0.35 s. After feeding, the mixture was kept at 12℃ and the reaction continued for 20 minutes. The two reactors were unloaded, and the reaction liquid was transferred to a centrifuge for separation. The centrifugation speed was 800 rpm and the centrifugation time was 12 minutes, yielding 745.2 kg of crude benzoyl peroxide and 6731.8 kg of recycled mother liquor from the second synthesis. The recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: sodium chloride 23.63%, sodium hydroxide 0.57%, hydrogen peroxide 0.28%, sodium benzoate 2.6%, sodium benzoate peroxide 0.06%, and the balance being water; (4) Add the crude benzoyl peroxide from step (3) into a rinsing tank and wash continuously with water (the water volume is 70% of that of the traditional method). Then, send it to a centrifuge by a conveying device for centrifugation to separate solid and liquid and obtain 746.5 kg / h of benzoyl peroxide product (content 74.6%). The centrifugation speed is 800 rpm and the centrifugation time is 12 min. The yield of benzoyl chloride is 98.5%.

[0028] Example 5 The preparation method of benzoyl peroxide includes the following steps: (1) Add 2700 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 500 rpm and a cooling temperature of 10℃; (2) 660 kg of the initial synthesis recycled mother liquor, 150 kg of 32 wt% sodium hydroxide solution, 60 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor by a self-priming pump. The initial synthesis recycled mother liquor (733 kg / h), sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), and benzoyl chloride (200 kg / h) were fed after being treated by a premixer. Hydrogen peroxide (67 kg / h) and sodium hydroxide solution (167 kg / h) were fed directly by a self-priming pump. The stirring speed of the premixer was 800 rpm and the premixing time was 0.8 s. After feeding (continuous feeding for 54 min), the reaction was kept at 11 °C for 50 min to obtain the initial reaction product of benzoyl peroxide. (3) Continue to feed the first reactor at the feeding rate of step (2) for 50 minutes. At the same time, the first reactor is kept at 11°C for reaction. The initial reaction product begins to overflow into the second reactor connected in series with the first reactor. When the second reactor reaches the stirring level, start stirring at 450 rpm. The recycled mother liquor (4500 kg / h), sodium dodecylbenzenesulfonate aqueous solution (1.2 kg / h), sodium hydroxide solution (420 kg / h) and benzoyl chloride (420 kg / h) obtained from the initial synthesis are fed after being treated by the premixer. Hydrogen peroxide (160 kg / h) is fed directly through the self-priming pump at the same time. The stirring speed of the premixer is 800 rpm and the premixing time is 0.3 s. After feeding, the mixture was kept at 10°C and the reaction continued for 11 minutes. The two reactors were unloaded, and the reaction liquid was transferred to a centrifuge for separation. The centrifugation speed was 1000 rpm and the centrifugation time was 11 minutes, yielding 671.2 kg of crude benzoyl peroxide and 7663.6 kg of recycled mother liquor from the second synthesis. The recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: sodium chloride 22.94%, sodium hydroxide 0.52%, hydrogen peroxide 0.19%, sodium benzoate 3.1%, sodium benzoate peroxide 0.07%, and the balance being water; (4) Add the crude benzoyl peroxide from step (3) into a rinsing tank and wash continuously with water (the water volume is 80% of that of the traditional method). Then, send it to a centrifuge by a conveying device for centrifugation to separate solid and liquid and obtain 668.4 kg / h of benzoyl peroxide product (content 75.3%). The centrifugation speed is 1000 rpm and the centrifugation time is 11 min. The yield of benzoyl chloride is 97.9%.

[0029] Comparative Example 1 The preparation method of benzoyl peroxide includes the following steps: (1) Add 2600 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 350 rpm and a cooling temperature of 9℃; (2) 760 kg of the initial synthesis recycled mother liquor, 185 kg of 32 wt% sodium hydroxide solution, 72 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride are simultaneously fed into the first reactor through a high-level tank. The initial synthesis recycled mother liquor (844 kg / h), sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), and benzoyl chloride (200 kg / h) are fed after being treated by a premixer. Hydrogen peroxide (80 kg / h) and sodium hydroxide solution (206 kg / h) are added. Simultaneously, the material was directly fed through a high-level tank at a rate of kg / h. The stirring speed of the premixer was 800 rpm, and the premixing time was 0.8 s. After feeding, the reaction was kept at 10℃ for 45 min. After the reaction, 179.3 kg of crude benzoyl peroxide and 3618.2 kg of recycled mother liquor from the second synthesis were obtained by centrifugation (the mother liquor recycling rate was 92.9%). The centrifugation speed was 800 rpm, and the centrifugation time was 13 min. The recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: sodium chloride 22.5%, sodium hydroxide 0.7%, hydrogen peroxide 0.45%, sodium benzoate 4.8%, sodium peroxide benzoate 0.06%, and the balance being water; (3) Add the crude benzoyl peroxide from step (2) into a rinsing tank and wash continuously with water (the amount of water used is 80% of that used in the traditional method). Then, send it to a centrifuge by a conveying device for centrifugation to separate the solid and liquid components and obtain 194.3 kg of benzoyl peroxide product (content 73.8%). The centrifugation speed is 800 rpm and the centrifugation time is 13 min. The yield of benzoyl chloride is 93.1%.

[0030] Conclusion: Compared with Example 1, the increased proportion of sodium hydroxide and hydrogen peroxide in Comparative Example 1 resulted in more side reactions of benzoyl chloride and a lower yield of benzoyl peroxide product based on benzoyl chloride.

[0031] Comparative Example 2 The preparation method of benzoyl peroxide includes the following steps: (1) Add 3360 kg of the initial synthesis of recycled mother liquor to the first reactor, start stirring and cooling, with a stirring speed of 350 rpm and a cooling temperature of 9℃; (2) 163 kg of 32 wt% sodium hydroxide solution, 60 kg of 35 wt% hydrogen peroxide, 0.5 kg of 2 wt% sodium dodecylbenzenesulfonate aqueous solution, and 180 kg of benzoyl chloride were simultaneously fed into the first reactor through a high-level tank. Sodium dodecylbenzenesulfonate aqueous solution (0.56 kg / h), benzoyl chloride (200 kg / h), hydrogen peroxide (67 kg / h), and sodium hydroxide solution (181 kg / h) were simultaneously fed directly through the high-level tank. After feeding, the reaction was kept at 10°C for 45 min. After the reaction, 181.6 kg of crude benzoyl peroxide and 3581.9 kg of recycled mother liquor from the second synthesis were obtained by centrifugation. The centrifugation speed was 800 rpm and the centrifugation time was 13 min. The recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: sodium chloride 22.3%, sodium hydroxide 0.42%, hydrogen peroxide 0.3%, sodium benzoate 4.3%, sodium peroxide 0.06%, and the balance being water; (3) Add the crude benzoyl peroxide from step (2) into a rinsing tank and wash continuously with water (the amount of water used is 80% of that used in the traditional method). Then, send it to a centrifuge for centrifugation to separate the solid and liquid components and obtain 194.2 kg of benzoyl peroxide product (content 74.0%). The centrifugation speed is 800 rpm and the centrifugation time is 13 min. The yield of benzoyl chloride is 93.2%.

[0032] Conclusion: Compared with Example 1, Comparative Example 2 did not premix the multiple materials, resulting in poor material dispersion, reduced the conversion rate of the main reaction of benzoyl chloride, and a lower yield of benzoyl peroxide product based on benzoyl chloride.

[0033] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing benzoyl peroxide, characterized in that, Includes the following steps: (1) Add water to the first reaction vessel and begin stirring and cooling; (2) Sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are simultaneously fed into the first reactor through a high-level tank or self-priming pump. After feeding, the reaction is kept at a constant temperature. After the reaction in the first reactor is completed, the reactants are centrifuged to obtain crude benzoyl peroxide and the mother liquor obtained from the initial synthesis. (3) The crude benzoyl peroxide from step (2) is washed with water and separated into solid and liquid components to obtain the finished benzoyl peroxide product; (4) Take out two or three parts of the recycled mother liquor obtained from the initial synthesis, add the first part of the recycled mother liquor obtained from the initial synthesis into the first reaction vessel, and start stirring and cooling; (5) When two parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the second part of the recycled mother liquor obtained from the initial synthesis, sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are simultaneously fed into the first reactor through a high-level tank or self-priming pump. Before feeding, multiple materials containing at least benzoyl chloride are premixed through a premixer. After feeding, the reaction is kept at a constant temperature. After the reaction in the first reactor is completed, the crude benzoyl peroxide and the recycled mother liquor obtained from the second synthesis are obtained by centrifugation. Alternatively, when three parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the recycled mother liquor obtained from the initial synthesis in the second part, sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are simultaneously fed into the first reactor through a high-level tank or self-priming pump. Before feeding, multiple materials containing at least benzoyl chloride are pre-mixed by a premixer. After the initial reaction raw materials are fed, the first reactor is kept warm to react and obtain the initial reaction product of benzoyl peroxide. The recycled mother liquor obtained from the initial synthesis in the third part, sodium hydroxide solution, hydrogen peroxide, surfactant aqueous solution and benzoyl chloride are continuously fed into the first reactor. At the same time, the first reactor is kept warm to react. The initial reaction product containing benzoyl peroxide in the first reactor begins to overflow into the second reactor connected in series with the first reactor. When the second reactor reaches the stirring liquid level, the stirrer of the second reactor is turned on to continue stirring the reaction. After the reaction is completed, the reaction liquids of the two reactors are combined and centrifuged to obtain crude benzoyl peroxide and the recycled mother liquor obtained from the second synthesis. The material premixing process can be selected from the following three methods: ①The recycled mother liquor, surfactant aqueous solution and benzoyl chloride obtained from the initial synthesis in the second part are fed into the feed after being treated by a premixer. Hydrogen peroxide and sodium hydroxide solution are fed directly into the feed at the same time through a high-level tank or a self-priming pump. ②The recycled mother liquor, surfactant aqueous solution, benzoyl chloride and hydrogen peroxide obtained from the initial synthesis in the second part are fed into the feed after being treated by a premixer, while sodium hydroxide solution is fed directly into the feed through a high-level tank or a self-priming pump at the same time. ③The recycled mother liquor, surfactant aqueous solution, benzoyl chloride, hydrogen peroxide and sodium hydroxide solution obtained from the initial synthesis in Part II are fed into the feed after being treated by a premixer; (6) The crude benzoyl peroxide from step (5) is washed with water and separated into solid and liquid components to obtain the finished benzoyl peroxide product.

2. The method for preparing benzoyl peroxide according to claim 1, characterized in that, The production method of this invention is either intermittent production or continuous production.

3. The method for preparing benzoyl peroxide according to claim 1, characterized in that, Start stirring and cooling in step (1) or step (4), with a stirring speed of 300-600 rpm and a cooling temperature of 5-15℃.

4. The method for preparing benzoyl peroxide according to claim 1, characterized in that, The recycled mother liquor obtained from the initial synthesis or the recycled mother liquor obtained from the second synthesis comprises the following components by mass percentage: 18-25% sodium chloride, 0.4-0.6% sodium hydroxide, 0.2-0.4% hydrogen peroxide, 1-5% sodium benzoate, 0.01-0.1% sodium peroxybenzoate, and the balance being water; in step (2) or step (5), the concentration of sodium hydroxide solution is 20-32 wt%, the concentration of surfactant aqueous solution is 2 wt%, and the concentration of hydrogen peroxide is 27.5-35 wt%.

5. The method for preparing benzoyl peroxide according to claim 1, characterized in that, In step (2) or step (5), the molar ratio of benzoyl chloride, sodium hydroxide and hydrogen peroxide in hydrogen peroxide is 1:(1.05-1.4):(0.6-0.8). In step (2), the weight ratio of the surfactant aqueous solution to hydrogen peroxide is (0.001-0.01):1; In step (5), when two parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the weight ratio of the recycled mother liquor obtained from the initial synthesis, the surfactant aqueous solution and the hydrogen peroxide in the second part is (10-40):(0.001-0.01):1; In step (5), when three parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the total amount of the recycled mother liquor obtained from the initial synthesis in the second part and the recycled mother liquor obtained from the initial synthesis in the third part, the weight ratio of the surfactant aqueous solution and hydrogen peroxide is (10-40):(0.001-0.01):

1.

6. The method for preparing benzoyl peroxide according to claim 1, characterized in that, The surfactant in step (2) or step (5) is any one of sodium dodecylbenzenesulfonate, sodium dodecyl sulfate, or sodium dodecyl sulfonate.

7. The method for preparing benzoyl peroxide according to claim 1, characterized in that, In step (2), the heat preservation reaction temperature is 5-15℃ and the heat preservation reaction time is 20-60min; In step (5), the stirring speed of the premixer is 600-1000 rpm, and the premixing time is 0.5-1 s; In step (5), when two parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), the reaction is kept warm after the feeding is completed. After the reaction in the first reactor is completed, crude benzoyl peroxide and recycled mother liquor obtained from the second synthesis are separated. The temperature of the warm reaction is 5-15℃ and the reaction time is 20-60min. Alternatively, in step (5), when three parts are taken out from the recycled mother liquor obtained from the initial synthesis in step (4), after the initial reaction raw materials are fed in, the first reactor is kept at a constant temperature for 40-60 minutes and 8-15°C to obtain the initial reaction product of benzoyl peroxide; the first reactor is fed in continuously for the second time, while the first reactor is kept at a constant temperature of 8-15°C. The initial reaction product containing benzoyl peroxide in the first reactor begins to overflow into the second reactor connected in series with the first reactor. After the initial reaction product containing benzoyl peroxide in the first reactor overflows into the second reactor connected in series with the first reactor, the stirrer of the second reactor is turned on when the stirring liquid level is reached. The total time for the second continuous feeding into the first reactor and the stirring reaction in the second reactor is 50-80 minutes and the reaction temperature is 8-15°C. After the reaction is completed, the reaction liquids of the two reactors are combined and centrifuged to obtain crude benzoyl peroxide and the recycled mother liquor obtained from the second synthesis.

8. The method for preparing benzoyl peroxide according to claim 1, characterized in that, In step (2) or step (5), the centrifugation speed is 600-1200 rpm and the centrifugation time is 10-20 min.

9. The method for preparing benzoyl peroxide according to claim 1, characterized in that, In step (3) or step (6), crude benzoyl peroxide is added to a rinsing vessel and washed continuously with water. Then, it is sent to a centrifuge by a conveying device for centrifugal separation to obtain the finished benzoyl peroxide product. The centrifugation speed is 600-1200 rpm and the centrifugation time is 10-20 min.