A continuous process for the preparation of dicumyl peroxide

Abstract

The present application relates to the technical field of preparation of dicumyl peroxide, and provides a continuous preparation method of dicumyl peroxide, which can realize the combination of high conversion rate of raw materials and high selectivity of products and the safety of reaction process. The continuous preparation method of dicumyl peroxide comprises the following steps: (1) condensation reaction of cumene hydroperoxide and α, α-dimethylbenzyl alcohol is carried out in a kettle reactor to which an acidic catalyst aqueous solution is added at 30-55 ℃, and vacuum dehydration is carried out during the condensation reaction, and the conversion rate of cumene hydroperoxide is controlled to be 70-90%; (2) the reaction mixture obtained in step (1) is sent into a micro-channel reactor, and condensation reaction is continuously carried out at 60-90 ℃ in the presence of additional acidic catalyst aqueous solution, so that the dicumyl peroxide is prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of dicumyl peroxide preparation, in particular to a continuous preparation method of dicumyl peroxide. BACKGROUND

[0002] Dicumyl peroxide is a most commonly used symmetrical dialkyl organic peroxide, also known as vulcanizing agent DCP, white crystal, melting point 39℃-40℃, decomposition temperature 120℃-125℃, stable at room temperature, gradually turns yellow under light. The theoretical active oxygen content is 5.92%. Dicumyl peroxide can be used as a vulcanizing agent for natural rubber, synthetic rubber, such as a vulcanizing agent for ethylene propylene diene rubber (EPDM), nitrile rubber and silicone rubber, etc. Dicumyl peroxide can also be used as an initiator for polymerization reaction and as a crosslinking agent for polyethylene resin, such as commonly used as a crosslinking agent for polyethylene (PE), chlorinated polyethylene (CPE), polystyrene (PS). Dicumyl peroxide can also be used as an initiator for the synthesis of expandable polystyrene (EPS), a blowing agent for polyethylene vinyl acetate (EVA), etc. After DCP crosslinking, the physical properties of the polymer are greatly improved, and the heat resistance, chemical resistance, pressure resistance, crack resistance and mechanical strength are increased. DCP is widely used in the industries of wire and cable, shoemaking, building materials, etc. In recent years, with the continuous expansion of the market of high molecular materials, the demand for DCP is increasing year by year, and the market potential is huge.

[0003] At present, the production of dicumyl peroxide in industry all adopts batch kettle process. This process uses isopropylbenzene as raw material, oxidizes isopropylbenzene into hydrogen peroxide isopropylbenzene (CHP) through air oxidation, and generates α,α-dimethylbenzyl alcohol (DMBA) through reduction reaction with part of hydrogen peroxide isopropylbenzene. Then, dicumyl peroxide (DCP) is generated through condensation reaction of hydrogen peroxide isopropylbenzene and α,α-dimethylbenzyl alcohol under the action of an acid catalyst. After that, qualified products are obtained through processes such as alkali washing, water washing and crystallization. The condensation reaction process is as follows:

[0004] Main reaction:

[0005]

[0006] Side reaction:

[0007]

[0008] From the reaction process, the main reaction is a dehydration chemical equilibrium reaction process. In the condensation reaction process, the main side reactions include the dehydration of DMBA to generate alpha-methyl styrene (abbreviated as AMS), the acid-catalyzed decomposition of CHP to generate phenol and acetone, the acid-catalyzed decomposition of DCP to generate phenol, acetone and DMBA, and then the acid-catalyzed dehydration of DMBA to generate AMS. The side reactions of phenol and AMS occur to generate 4-cumyl phenol, and AMS itself polymerizes to generate dimers and trimers. The above decomposition reactions, alkylation reactions and polymerization reactions are all strong exothermic reactions, and once the reaction is out of control, it will cause an explosion.

[0009] Therefore, the condensation process has the following technical problems: (1) the main reaction is an acid-catalyzed reaction, but CHP and DCP are prone to secondary decomposition under the action of acid catalysis; (2) the main reaction is an equilibrium reaction, and the water generated in the system needs to be removed in time; (3) the reaction endpoint is difficult to control, the raw materials are not completely reacted, which affects the product quality, and excessive reaction leads to the secondary decomposition of DCP.

[0010] Patent US4266081A discloses a method for preparing dicumyl peroxide using a strong acid weak base salt (such as zinc chloride) as a catalyst. This patent has the problems of easy hydrolysis of the catalyst, strong corrosion and large amount of use.

[0011] Patent US4413148A discloses a method for preparing dicumyl peroxide. This patent uses a polar solvent such as triethyl phosphate, which is hardly distilled by water in the process of continuously removing water generated in the reaction, to achieve the purpose of inhibiting the decomposition of CHP and DCP. However, there is still a problem of low selectivity of DCP, especially when the CHP conversion rate reaches more than 90%, the selectivity of DCP is only about 90%.

[0012] Patents CN103145597B and CN104860861A disclose a production method of dicumyl peroxide, which relates to a method for reducing the production of by-products in the condensation reaction process of dicumyl peroxide. This patent uses a batch production process, and the selectivity of DCP is less than 94%, which still has the problem of low selectivity of DCP in the condensation reaction.

[0013] Patent CN102827051A relates to a synthesis method of dicumyl peroxide, and discloses a method for synthesizing dicumyl peroxide using pure benzyl alcohol and an oxidizing solution as raw materials. Although this patent has reduced the content of by-products such as phenol and acetone, the content of by-products such as phenol and acetone is still as high as 3.5-4.2%, which has the problems of low yield of DCP product and high content of by-products.

[0014] Patent CN113845457A discloses a method for preparing dicumyl peroxide by using SO4 2-A method for preparing cumene hydroperoxide by dehydrating and condensing dimethyl benzyl alcohol and cumene hydroperoxide in the presence of a ZnCl2-HY solid acid catalyst. The main disadvantages of this patent are that the solid acid catalyst has poor activity, high reaction temperature is required, the decomposition of raw material cumene hydroperoxide and product cumene hydroperoxide is serious, the effective utilization rate of raw material and the yield of product are low; on the other hand, with the increase of the number of uses, the loss of active components of the catalyst leads to the decrease of acid sites of the catalyst and the decrease of catalytic performance of the catalyst, and the service life of the catalyst is greatly reduced.

[0015] Patent CN109384699A discloses an online full-continuous flow production process for directly preparing organic peroxide from hydrogen peroxide as raw material. This patent has the problems of large catalyst dosage, long residence time, serious decomposition of organic peroxide, and low product selectivity.

[0016] In summary, the condensation process for the industrial production of cumene hydroperoxide has the problems of large catalyst dosage, poor product selectivity, poor process controllability, low safety factor and / or low production efficiency. SUMMARY

[0017] In view of the deficiencies of the prior art, the present application provides a continuous preparation method for cumene hydroperoxide. The preparation method of the present application can realize the consideration of high conversion rate of raw material and high selectivity of product, and the reaction process is safe.

[0018] To achieve the purpose, the present application provides the following technical solutions:

[0019] The present application provides a continuous preparation method for cumene hydroperoxide, comprising the following steps:

[0020] (1) condensing hydrogen peroxide cumene and α,α-dimethyl benzyl alcohol in a kettle reactor with an added aqueous solution of an acidic catalyst at 30-55℃, and performing vacuum dehydration during the condensation reaction, and controlling the conversion rate of hydrogen peroxide cumene to be 70-90%;

[0021] (2) feeding the reaction mixture obtained in step (1) into a microchannel reactor, and continuing the condensation reaction at 60-90℃ in the presence of an additional aqueous solution of an acidic catalyst to prepare the cumene hydroperoxide;

[0022] wherein the mass concentration of the aqueous solution of the acidic catalyst used in step (1) is lower than that of the aqueous solution of the acidic catalyst used in step (2); and the amount of the acidic catalyst used in step (1) is less than that of the acidic catalyst used in step (2).

[0023] In some embodiments, the mass concentration of the aqueous acidic catalyst solution used in step (1) is 10-40 wt%, preferably 20-35 wt%, more preferably 25-30 wt%;

[0024] The mass concentration of the aqueous acidic catalyst solution used in step (2) is 50-90 wt%, preferably 60-85 wt%, more preferably 75-80 wt%.

[0025] In some embodiments, the amount of the acidic catalyst used in step (1) is 10-200 ppm, preferably 50-150 ppm, more preferably 80-120 ppm, based on the total mass of the cumene hydroperoxide;

[0026] The amount of the acidic catalyst used in step (2) is 500-5000 ppm, preferably 1000-4000 ppm, more preferably 2000-3000 ppm, based on the total mass of the cumene hydroperoxide.

[0027] Preferably, in step (1), the reaction temperature of the condensation reaction is 40-50°C, preferably 43-47°C;

[0028] And / or, in step (1), the vacuum degree of the tank reactor is 1-10 KPa, preferably 3-8 KPa, more preferably 5-7 KPa, and the water in the system is continuously removed as the reaction proceeds under vacuum;

[0029] And / or, in step (1), the reaction time of the condensation reaction is 1-6 h, preferably 2-5 h, more preferably 3-4 h; in step (2), the reaction time of the condensation reaction is 10-60 s, preferably 20-50 s, more preferably 30-40 s;

[0030] And / or, in step (2), the reaction temperature of the condensation reaction is 65-85°C, preferably 70-80°C;

[0031] Preferably, in step (1), the conversion rate of the cumene hydroperoxide is controlled to be 75-88%, preferably 78-84%.

[0032] In some embodiments, in step (1), the cumene hydroperoxide and the solvent cumene are mixed to form a cumene hydroperoxide solution, which is then added to the reaction system; the mass concentration of the cumene hydroperoxide solution is 24-88 wt%, preferably 35-70 wt%, more preferably 50-60 wt%.

[0033] In some embodiments, in step (1), the molar ratio of the cumene hydroperoxide to the α,α-dimethylbenzyl alcohol is (0.8-1.5):1, preferably (0.9-1.2):1, more preferably (1.0-1.1):1.

[0034] In some embodiments, in steps (1) and (2), the acid catalysts are independently selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and trichloroacetic acid; preferably one or more of sulfuric acid, perchloric acid, p-toluenesulfonic acid, and dodecylbenzenesulfonic acid; more preferably one or both of dodecylbenzenesulfonic acid or p-toluenesulfonic acid.

[0035] The technical solution provided by the present application has the following beneficial effects:

[0036] The present application adopts the combination of a kettle reactor and a micro-channel reactor, performs a first-stage condensation reaction at 30-55℃ in the kettle reactor, controls the conversion rate of cumene hydroperoxide in this stage to be in the range of 70-90%, then performs a second-stage condensation reaction at 60-90℃ in the micro-channel reactor with additional addition of an appropriate amount of acid catalyst, and makes the acid catalyst usage and concentration in the first-stage condensation reaction lower than those in the second-stage condensation reaction. In the preparation process of the present application, rapid conversion of cumene hydroperoxide and low decomposition rate of the product are realized, the balance between high conversion rate of raw materials and high selectivity of products is achieved, and the intrinsic safety of the reaction process is realized. DETAILED DESCRIPTION

[0037] In order to facilitate the understanding of the present application, the present application will be further described below in conjunction with examples. It should be understood that the following examples are only for better understanding of the present application, and do not mean that the present application is limited to the following examples only.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0039] The present application provides a continuous preparation method of dicumyl peroxide, comprising the following steps:

[0040] (1) performing a condensation reaction of cumene hydroperoxide and α,α-dimethylbenzyl alcohol in a kettle reactor with the addition of an aqueous solution of an acid catalyst at 30-55℃, and performing vacuum dehydration during the condensation reaction, and controlling the conversion rate of cumene hydroperoxide to be 70-90%;

[0041] (2) feeding the reaction mixture obtained in step (1) into a micro-channel reactor, and continuing to perform a condensation reaction at 60-90℃ in the presence of an additional aqueous solution of an acid catalyst, to prepare the dicumyl peroxide;

[0042] The mass concentration of the acidic catalyst aqueous solution used in step (1) is lower than that of the acidic catalyst aqueous solution used in step (2); and the amount of the acidic catalyst used in step (1) is less than that of the acidic catalyst used in step (2).

[0043] In the present application, the kettle reactor can be a continuous kettle reactor.

[0044] In the present application, the kettle reactor can be a continuous kettle reactor.

[0045] In the preferred embodiments, the mass concentration of the acidic catalyst aqueous solution used in step (1) is 10-40 wt%, preferably 20-35 wt%, and more preferably 25-30 wt%; and the mass concentration of the acidic catalyst aqueous solution used in step (2) is 50-90 wt%, preferably 60-85 wt%, and more preferably 75-80 wt%. The use of the preferred acidic catalyst aqueous solution concentration combination in steps (1) and (2) is conducive to better balancing the conversion rate and product selectivity.

[0046] In the preferred embodiments, the amount of the acidic catalyst used in step (1) is 10-200 ppm, preferably 50-150 ppm, and more preferably 80-120 ppm, based on the total mass of the cumene hydroperoxide; and the amount of the acidic catalyst used in step (2) is 500-5000 ppm, preferably 1000-4000 ppm, and more preferably 2000-3000 ppm, based on the total mass of the cumene hydroperoxide. The use of the preferred acidic catalyst aqueous solution concentration combination in steps (1) and (2) is conducive to better balancing the conversion rate and product selectivity.

[0047] In some preferred embodiments, the mass concentration of the aqueous acidic catalyst solution used in step (1) is 25-30 wt%; the mass concentration of the aqueous acidic catalyst solution used in step (2) is 75-80 wt%; the amount of the acidic catalyst used in step (1) is 80-120 ppm based on the total mass of the cumene hydroperoxide, and the amount of the acidic catalyst used in step (2) is 2000-3000 ppm. With this preferred mode, both high conversion rate and product selectivity can be better balanced.

[0048] In preferred embodiments, the reaction temperature of the condensation reaction in step (1) is 40-50°C, preferably 43-47°C.

[0049] In some embodiments, the vacuum degree of the tank reactor in step (1) is 1-10 KPa, preferably 3-8 KPa, and more preferably 5-7 KPa.

[0050] In some embodiments, the reaction time of the condensation reaction in step (1) is 1-6 h, preferably 2-5 h, and more preferably 3-4 h; and the reaction time of the condensation reaction in step (2) is 10-60 s, preferably 20-50 s, and more preferably 30-40 s. With the combination of the tank continuous process and the micro-channel continuous process, the reaction temperature, the amount of catalyst, and the conversion rate of the cumene hydroperoxide in the first stage condensation reaction are controlled, and the residence time in the two stages is changed, which is conducive to balancing the better conversion rate of raw materials, high selectivity of products, and the intrinsic safety of the reaction process.

[0051] In preferred embodiments, the reaction temperature of the condensation reaction in step (2) is 65-85°C, preferably 70-80°C.

[0052] In preferred embodiments, the conversion rate of the cumene hydroperoxide is controlled to be 75-88% in step (1), and preferably 78-84%.

[0053] In some embodiments, the cumene hydroperoxide and the solvent cumene are mixed to form a cumene hydroperoxide solution, which is then added to the reaction system in step (1); the mass concentration of the cumene hydroperoxide solution is 24-88 wt%, preferably 35-70 wt%, and more preferably 50-60 wt%.

[0054] In some embodiments, the molar ratio of the cumene hydroperoxide to the α,α-dimethylbenzyl alcohol in step (1) is (0.8-1.5):1, preferably (0.9-1.2):1, and more preferably (1.0-1.1):1.

[0055] In some embodiments, in step (1) and step (2), the acidic catalyst is independently selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and trichloroacetic acid; preferably one or more of sulfuric acid, perchloric acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid; more preferably one or both of dodecylbenzenesulfonic acid and p-toluenesulfonic acid. The use of the preferred acidic catalysts, especially the use of the preferred dodecylbenzenesulfonic acid and / or p-toluenesulfonic acid, in the process of the present application is conducive to better balancing the better raw material conversion rate and product selectivity.

[0056] The main reaction of the present application is a chemical equilibrium reaction process. As the condensation reaction proceeds, the amount of water produced gradually accumulates, and the concentration of the acid catalyst in the reaction system gradually decreases, thereby causing the reaction rate to slow down. In the condensation reaction process of step (1) of the present application, the water produced in the reaction is removed from the reaction system under vacuum in a timely manner, thereby ensuring a sufficient concentration of the acid catalyst to achieve the catalytic purpose. The conditions for the condensation reaction of CHP and DMBA to prepare DCP are relatively harsh. In order to ensure high conversion of CHP, high selectivity of DCP and intrinsic safety of the reaction, the present application uses a tank continuous reaction process in the first step. The reaction is completed under the conditions of low temperature, low catalyst dosage (based on CHP), low catalyst mass concentration and vacuum dehydration. By controlling the conversion rate of CHP in the range of 70-90%, the selectivity of dicumyl peroxide can be maintained above 95%. The present inventors have found that if the conversion rate of CHP is less than 70%, CHP cannot be completely converted in the second step reaction; if the conversion rate of CHP is greater than 90%, DCP decomposes to cause the selectivity to rapidly decrease. Under the premise of high conversion of CHP, in order to ensure high selectivity of DCP, the present application uses a microchannel continuous reaction process in the second step reaction. The reaction is completed under the conditions of high temperature, high catalyst dosage (based on CHP), high catalyst mass concentration and no dehydration. By utilizing the strong mass transfer and heat transfer rate, low holdup, short residence time and intrinsic safety of the microchannel reactor, by additionally adding an appropriate amount of high-concentration acid catalyst and shortening the residence time, rapid conversion of CHP and low decomposition rate of DCP are achieved, thereby avoiding the occurrence of side reactions such as decomposition, alkylation and polymerization, and further reducing the risk of reaction runaway. By using the preparation method of the present application, better raw material conversion rate and product selectivity can be achieved.

[0057] Compared with the batch process, the combination process of the tank continuous process and the microchannel continuous process used in the present application has the advantages of simple operation, high degree of automation, easy control of the reaction process, fewer side reactions, stable product quality and high production efficiency.

[0058] The present application will be further illustrated by specific examples, but should not be understood as being limited to the examples.

[0059] When specific experimental procedures or conditions are not indicated in the examples, they can be carried out according to the operation of the corresponding conventional experimental procedures or conditions in the technical field. When the manufacturer of the reagent or instrument is not indicated, it is a conventional product that can be obtained on the market.

[0060] The reaction conversion and selectivity were determined by using liquid chromatography external standard curve method.

[0061] The chromatographic analysis conditions are as follows: Shimadzu liquid chromatograph SPD-20A; column oven: CTO-10ASvp; column temperature: 35°C, chromatographic column: T3 column, mobile phase: water and acetonitrile, water / acetonitrile = 25:75 (vol / vol), total flow rate: 1 ml / min, residence time: 40 min, detector wavelength: 254 nm.

[0062] Example 1

[0063] (1) Under stirring, 1 L autoclave was sequentially added with α, α-dimethylbenzyl alcohol with a purity of 99.9%, 50 wt% cumene hydroperoxide solution (solvent: cumene) and 25 wt% p-toluenesulfonic acid aqueous solution, and reacted at a reaction temperature of 43°C and a vacuum degree of 5 KPa for 3 h. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 78%, and the selectivity of dicumyl peroxide was 98.5%. Among them, the molar ratio of cumene hydroperoxide to α, α-dimethylbenzyl alcohol was 1:1; based on the total mass of cumene hydroperoxide, the amount of p-toluenesulfonic acid was 80 ppm.

[0064] (2) The reaction mixture obtained in step (1) and additional 75 wt% p-toluenesulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by the laminar pump, and reacted at a reaction temperature of 70°C for 30 s. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 100%, and the selectivity of dicumyl peroxide was 98.2%. Among them, based on the total mass of cumene hydroperoxide, the amount of additional p-toluenesulfonic acid acid catalyst was 2000 ppm.

[0065] Example 2

[0066] (1) Under stirring, 1 L autoclave was sequentially added with α, α-dimethylbenzyl alcohol with a purity of 99.9%, 35 wt% cumene hydroperoxide solution (solvent: cumene) and 30 wt% dodecylbenzenesulfonic acid aqueous solution, and reacted at a reaction temperature of 47°C and a vacuum degree of 7 KPa for 4 h. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 84%, and the selectivity of dicumyl peroxide was 97.2%. Among them, the molar ratio of cumene hydroperoxide to α, α-dimethylbenzyl alcohol was 0.9:1; based on the total mass of cumene hydroperoxide, the amount of dodecylbenzenesulfonic acid was 10 ppm.

[0067] (2) The reaction mixture obtained in step (1) and additional 90wt% dodecylbenzenesulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by the laminar pump, and reacted at 80℃ for 50s. The conversion of cumene hydroperoxide was 100% and the selectivity of dicumyl peroxide was 96.7% by liquid chromatography analysis. The amount of additional dodecylbenzenesulfonic acid catalyst was 3000ppm based on the total mass of cumene hydroperoxide.

[0068] Example 3

[0069] (1) Under stirring, 1L autoclave was sequentially added with 99.9% purity α,α-dimethylbenzyl alcohol, 88wt% cumene hydroperoxide solution (solvent is cumene) and 20wt% p-toluenesulfonic acid aqueous solution, and reacted at 40℃ and vacuum degree of 1KPa for 2h. The conversion of cumene hydroperoxide was 90% and the selectivity of dicumyl peroxide was 97.8% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 1.5:1, and the amount of p-toluenesulfonic acid was 50ppm based on the total mass of cumene hydroperoxide.

[0070] (2) The reaction mixture obtained in step (1) and additional 50wt% p-toluenesulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by the laminar pump, and reacted at 65℃ for 20s. The conversion of cumene hydroperoxide was 100% and the selectivity of dicumyl peroxide was 97.5% by liquid chromatography analysis. The amount of additional p-toluenesulfonic acid catalyst was 500ppm based on the total mass of cumene hydroperoxide.

[0071] Example 4

[0072] (1) Under stirring, 1L autoclave was sequentially added with 99.9% purity α,α-dimethylbenzyl alcohol, 24wt% cumene hydroperoxide solution (solvent is cumene) and 10wt% p-toluenesulfonic acid aqueous solution, and reacted at 50℃ and vacuum degree of 10KPa for 6h. The conversion of cumene hydroperoxide was 75% and the selectivity of dicumyl peroxide was 97.6% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 1.1:1, and the amount of p-toluenesulfonic acid was 120ppm based on the total mass of cumene hydroperoxide.

[0073] (2) The reaction mixture obtained in step (1) and additional 60 wt% p-toluene sulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 85 °C for 40 s. The conversion of cumene hydroperoxide was 100% and the selectivity of dicumyl peroxide was 96.4% by liquid chromatography analysis. The amount of additional p-toluene sulfonic acid catalyst was 5000 ppm based on the total mass of cumene hydroperoxide.

[0074] Example 5

[0075] (1) Under stirring, 1 L autoclave was sequentially charged with 99.9% purity of a,a-dimethylbenzyl alcohol, 60 wt% cumene hydroperoxide solution (solvent is cumene) and 40 wt% dodecylbenzenesulfonic acid aqueous solution, and reacted at 30 °C and vacuum degree of 3 KPa for 1 h. The conversion of cumene hydroperoxide was 88% and the selectivity of dicumyl peroxide was 96.7% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1.2:1, and the amount of dodecylbenzenesulfonic acid was 150 ppm based on the total mass of cumene hydroperoxide.

[0076] (2) The reaction mixture obtained in step (1) and additional 85 wt% dodecylbenzenesulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 60 °C for 60 s. The conversion of cumene hydroperoxide was 100% and the selectivity of dicumyl peroxide was 96.5% by liquid chromatography analysis. The amount of additional dodecylbenzenesulfonic acid catalyst was 1000 ppm based on the total mass of cumene hydroperoxide.

[0077] Example 6

[0078] (1) Under stirring, 1 L autoclave was sequentially charged with 99.9% purity of a,a-dimethylbenzyl alcohol, 60 wt% cumene hydroperoxide solution (solvent is cumene) and 40 wt% dodecylbenzenesulfonic acid aqueous solution, and reacted at 30 °C and vacuum degree of 3 KPa for 1 h. The conversion of cumene hydroperoxide was 88% and the selectivity of dicumyl peroxide was 96.7% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1.2:1, and the amount of dodecylbenzenesulfonic acid was 150 ppm based on the total mass of cumene hydroperoxide.

[0079] (2) The reaction mixture obtained in step (1) and additional 80 wt% dodecylbenzenesulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 90 °C for 10 s. The conversion of cumene hydroperoxide was 100% and the selectivity of dicumyl peroxide was 96.9% by liquid chromatography analysis. The amount of additional dodecylbenzenesulfonic acid catalyst was 4000 ppm based on the total mass of cumene hydroperoxide.

[0080] Example 7 (compared with Example 1)

[0081] (1) Under stirring, 1 L autoclave was sequentially added with 99.9% purity a,a-dimethylbenzyl alcohol, 50 wt% cumene hydroperoxide solution (solvent is cumene) and 15 wt% p-toluenesulfonic acid aqueous solution, and reacted at 43 °C and vacuum degree of 5 KPa for 3 h. The conversion of cumene hydroperoxide was 75% and the selectivity of dicumyl peroxide was 97.6% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1:1; the amount of p-toluenesulfonic acid was 80 ppm based on the total mass of cumene hydroperoxide.

[0082] (2) The reaction mixture obtained in step (1) and additional 85 wt% p-toluenesulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 70 °C for 30 s. The conversion of cumene hydroperoxide was 100% and the selectivity of dicumyl peroxide was 96.2% by liquid chromatography analysis. The amount of additional p-toluenesulfonic acid catalyst was 2000 ppm based on the total mass of cumene hydroperoxide.

[0083] Compared with Example 1, under the condition that other conditions were basically the same, the product selectivity of Example 7 was inferior to that of Example 1 because no preferred concentration of acidic catalyst was used in steps (1) and (2) of Example 7.

[0084] Example 8 (compared with Example 1)

[0085] (1) Under stirring, 1 L autoclave was sequentially added with 99.9% purity a,a-dimethylbenzyl alcohol, 50 wt% cumene hydroperoxide solution (solvent is cumene) and 25 wt% p-toluenesulfonic acid aqueous solution, and reacted at 43 °C and vacuum degree of 5 KPa for 3 h. The conversion of cumene hydroperoxide was 72% and the selectivity of dicumyl peroxide was 97.3% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1:1; the amount of p-toluenesulfonic acid was 40 ppm based on the total mass of cumene hydroperoxide.

[0086] (2) The reaction mixture obtained in step (1) and additional 75wt% p-toluene sulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 70°C for 30s. The conversion of cumene hydroperoxide was 100% and the selectivity of di-cumyl peroxide was 96.8% by liquid chromatography analysis. The additional amount of p-toluene sulfonic acid catalyst was 1500ppm based on the total mass of cumene hydroperoxide.

[0087] Compared with Example 1, the product selectivity of Example 8 was worse than that of Example 1 under the same conditions.

[0088] Example 9 (compared with Example 4)

[0089] (1) Under stirring, 1L autoclave was sequentially added with 99.9% purity α,α-dimethyl benzyl alcohol, 24wt% cumene hydroperoxide solution (solvent is cumene) and 10wt% sulfuric acid aqueous solution, and reacted at 50°C and 10KPa vacuum degree for 6h. The conversion of cumene hydroperoxide was 80% and the selectivity of di-cumyl peroxide was 96.3% by liquid chromatography analysis. The molar ratio of cumene hydroperoxide to α,α-dimethyl benzyl alcohol was 1.1:1, and the amount of sulfuric acid was 120ppm based on the total mass of cumene hydroperoxide.

[0090] (2) The reaction mixture obtained in step (1) and additional 60wt% sulfuric acid aqueous solution were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 85°C for 40s. The conversion of cumene hydroperoxide was 99.6% and the selectivity of di-cumyl peroxide was 96.1% by liquid chromatography analysis. The additional amount of sulfuric acid catalyst was 5000ppm based on the total mass of cumene hydroperoxide.

[0091] Compared with Example 4, the raw material conversion and product selectivity of this example were worse than those of Example 4 under the same conditions.

[0092] Example 10 (compared with Example 2)

[0093] (1) Under stirring, 1 L autoclave was charged with 99.9% purity of a,a-dimethylbenzyl alcohol, 35 wt% cumene hydroperoxide solution (solvent: cumene) and 30 wt% aqueous solution of perchloric acid, and reacted at 47 °C and 7 KPa vacuum for 4 h. By liquid chromatography analysis, the conversion of cumene hydroperoxide was 80%, and the selectivity of dicumyl peroxide was 96.4%. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 0.9:1; and the amount of perchloric acid was 10 ppm based on the total mass of cumene hydroperoxide.

[0094] (2) The reaction mixture obtained in step (1) and additional 90 wt% aqueous solution of perchloric acid were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 80 °C for 50 s. By liquid chromatography analysis, the conversion of cumene hydroperoxide was 99.7%, and the selectivity of dicumyl peroxide was 96.2%. The amount of additional catalyst of perchloric acid was 3000 ppm based on the total mass of cumene hydroperoxide.

[0095] Compared with Example 2, under the condition that other conditions are basically the same, the raw material conversion rate and product selectivity of the present example are inferior to those of Example 2 because the preferred acidic catalyst is not used.

[0096] Comparative Example 1 (compared with Example 1)

[0097] Under stirring, 1 L autoclave was charged with 99.9 wt% purity of a,a-dimethylbenzyl alcohol, 50 wt% cumene hydroperoxide solution (solvent: cumene) and 25 wt% aqueous solution of p-toluenesulfonic acid, and reacted at 43 °C and 5 KPa vacuum for 8 h. By liquid chromatography analysis, the conversion of cumene hydroperoxide was 99.2%, and the selectivity of dicumyl peroxide was 88.5%. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1:1; and the amount of p-toluenesulfonic acid was 80 ppm based on the total mass of cumene hydroperoxide.

[0098] Comparative Example 2

[0099] 99.9 wt% purity of a,a-dimethylbenzyl alcohol and 50 wt% cumene hydroperoxide solution (solvent: cumene) were mixed uniformly, and then the mixed raw materials and 75 wt% aqueous solution of p-toluenesulfonic acid were simultaneously pumped into the micro-channel reactor by a laminar pump, and reacted at 70 °C for 30 s. By liquid chromatography analysis, the conversion of cumene hydroperoxide was 80.5%, and the selectivity of dicumyl peroxide was 95.5%. The molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1:1; and the amount of p-toluenesulfonic acid catalyst was 2000 ppm based on the total mass of cumene hydroperoxide.

[0100] Comparative Example 3 (compared with Example 1)

[0101] (1) Under stirring, a 1L autoclave was sequentially charged with a- a-dimethylbenzyl alcohol with a purity of 99.9%, 50wt% cumene hydroperoxide solution (solvent: cumene) and 5wt% p-toluenesulfonic acid aqueous solution, and reacted at a reaction temperature of 43°C and a vacuum degree of 5KPa for 3h. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 65%, and the selectivity of dicumyl peroxide was 98.0%. Among them, the molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1:1; and the amount of p-toluenesulfonic acid was 80ppm based on the total mass of cumene hydroperoxide.

[0102] (2) The reaction mixture obtained in step (1) and additional 75wt% p-toluenesulfonic acid aqueous solution were simultaneously pumped into a microchannel reactor by a laminar pump, and reacted at a reaction temperature of 70°C for 30s. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 95.5%, and the selectivity of dicumyl peroxide was 96.4%. Among them, the amount of additional p-toluenesulfonic acid acid catalyst was 2000ppm based on the total mass of cumene hydroperoxide.

[0103] Comparative Example 4 (compared with Example 1)

[0104] (1) Under stirring, a 1L autoclave was sequentially charged with a- a-dimethylbenzyl alcohol with a purity of 99.9%, 50wt% cumene hydroperoxide solution (solvent: cumene) and 35wt% p-toluenesulfonic acid aqueous solution, and reacted at a reaction temperature of 43°C and a vacuum degree of 5KPa for 3h. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 95%, and the selectivity of dicumyl peroxide was 93.2%. Among them, the molar ratio of cumene hydroperoxide to a,a-dimethylbenzyl alcohol was 1:1; and the amount of p-toluenesulfonic acid was 80ppm based on the total mass of cumene hydroperoxide.

[0105] (2) The reaction mixture obtained in step (1) and additional 75wt% p-toluenesulfonic acid aqueous solution were simultaneously pumped into a microchannel reactor by a laminar pump, and reacted at a reaction temperature of 70°C for 30s. Through liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 100%, and the selectivity of dicumyl peroxide was 92.1%. Among them, the amount of additional p-toluenesulfonic acid acid catalyst was 2000ppm based on the total mass of cumene hydroperoxide.

[0106] Comparative Example 5

[0107] (1) Under stirring, 1 L autoclave was sequentially charged with α, α-dimethylbenzyl alcohol with purity of 99.9%, 50 wt% cumene hydroperoxide solution (solvent is cumene) and 75 wt% p-toluene sulfonic acid aqueous solution, reacted for 3 h at reaction temperature of 43 ℃ and vacuum degree of 5 KPa, through liquid chromatography analysis, the conversion rate of cumene hydroperoxide is 95%, the selectivity of dicumyl peroxide is 93.2%. Among them, the molar ratio of cumene hydroperoxide to α, α-dimethylbenzyl alcohol is 1:1; based on the total mass of cumene hydroperoxide, the amount of p-toluene sulfonic acid is 1000 ppm.

[0108] (2) The reaction mixture obtained in step (1) and additional 10 wt% p-toluene sulfonic acid aqueous solution were simultaneously pumped into the micro-channel reactor by the laminar pump, reacted for 30 s at reaction temperature of 70 ℃, through liquid chromatography analysis, the conversion rate of cumene hydroperoxide is 100%, the selectivity of dicumyl peroxide is 78.6%. Among them, based on the total mass of cumene hydroperoxide, the amount of additional p-toluene sulfonic acid acid catalyst is 200 ppm.

[0109] Table 1 summarizes the experimental results

[0110]

[0111] From the experimental results of the examples and comparative examples, it can be seen that the continuous preparation of dicumyl peroxide by the method of the present application can simultaneously take into account high raw material conversion rate (for example, more than 99.5%) and high product selectivity (for example, more than 96%), and the reaction process is safe. Comparative examples 1-5 cannot simultaneously take into account high raw material conversion rate and high product selectivity.

[0112] From the comparison of example 1 and examples 7, 8, it can be seen that the use of preferred acid catalyst concentration and amount can simultaneously take into account better raw material conversion rate and better product selectivity.

[0113] From the comparison of example 4 and example 9, and the comparison of example 2 and example 10, it can be seen that the use of preferred acid catalyst is conducive to simultaneously taking into account better raw material conversion rate and product selectivity.

[0114] It is easily understood that the above examples are only examples for the purpose of clarity, and do not mean that the present application is limited to this. Based on the above description, other different forms of changes or variations can also be made by those skilled in the art. Here, it is not necessary and impossible to exhaust all the embodiments. The obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A continuous process for the preparation of dicumyl peroxide, characterized in that, The method comprises the following steps: (1) condensation reaction of cumene hydroperoxide and α, α-dimethylbenzyl alcohol is carried out in a tank reactor to which an acidic catalyst aqueous solution is added at 30-55℃, and vacuum dehydration is carried out during the condensation reaction, and the conversion rate of cumene hydroperoxide is controlled to be 70-90%; (2) the reaction mixture obtained in step (1) is sent into a micro-channel reactor, and the condensation reaction is continuously carried out at 60-90℃ in the presence of additional acidic catalyst aqueous solution to prepare the cumene hydroperoxide; wherein the mass concentration of the acidic catalyst aqueous solution used in step (1) is lower than that of the acidic catalyst aqueous solution used in step (2); and the amount of the acidic catalyst used in step (1) is less than that of the acidic catalyst used in step (2).

2. The continuous production process according to claim 1, characterized in that, The mass concentration of the acidic catalyst aqueous solution used in step (1) is 10-40wt%; The mass concentration of the acidic catalyst aqueous solution used in step (2) is 50-90wt%.

3. The continuous production process according to claim 2, characterized in that, The mass concentration of the acidic catalyst aqueous solution used in step (1) is 20-35wt%; The mass concentration of the acidic catalyst aqueous solution used in step (2) is 60-85wt%.

4. The continuous production process according to claim 3, characterized in that The mass concentration of the acidic catalyst aqueous solution used in step (1) is 25-30wt%; The mass concentration of the acidic catalyst aqueous solution used in step (2) is 75-80wt%.

5. The continuous production process according to any one of claims 1 to 4, characterized in that, The amount of the acidic catalyst used in step (1) is 10-200ppm based on the total mass of the cumene hydroperoxide; The amount of the acidic catalyst used in step (2) is 500-5000ppm based on the total mass of the cumene hydroperoxide.

6. The continuous production process according to claim 5, characterized in that, The amount of the acidic catalyst used in step (1) is 50-150ppm based on the total mass of the cumene hydroperoxide; The amount of the acidic catalyst used in step (2) is 1000-4000ppm based on the total mass of the cumene hydroperoxide.

7. The continuous production process according to claim 6, characterized in that The amount of the acidic catalyst used in step (1) is 80-120ppm based on the total mass of the cumene hydroperoxide; The amount of the acidic catalyst used in step (2) is 2000-3000ppm based on the total mass of the cumene hydroperoxide.

8. The continuous production process according to any one of claims 1 to 4, characterized in that, In step (1), the reaction temperature of the condensation reaction is 40-50℃; and / or, in step (1), the vacuum degree of the tank reactor is 1-10KPa; and / or, in step (1), the reaction time of the condensation reaction is 1-6h; in step (2), the reaction time of the condensation reaction is 10-60s; and / or, in step (2), the reaction temperature of the condensation reaction is 65-85℃.

9. The continuous production process according to claim 8, characterized in that, In step (1), the reaction temperature of the condensation reaction is 43-47℃; and / or, in step (1), the vacuum degree of the tank reactor is 3-8KPa; and / or, in step (1), the reaction time of the condensation reaction is 2-5h; in step (2), the reaction time of the condensation reaction is 20-50s; And / or, in step (2), the reaction temperature of the condensation reaction is 70-80°C.

10. The continuous production process according to claim 8, characterized in that, In step (1), the vacuum degree of the tank reactor is 5-7 KPa. And / or, in step (1), the reaction time of the condensation reaction is 3-4 h; in step (2), the reaction time of the condensation reaction is 30-40 s.

11. The continuous production process according to any one of claims 1 to 4, characterized in that, In step (1), the conversion rate of the cumene hydroperoxide is controlled to be 75-88%.

12. The continuous production process according to claim 11, characterized in that, In step (1), the conversion rate of the cumene hydroperoxide is controlled to be 78-84%.

13. The continuous production process according to any one of claims 1 to 4, characterized in that, In step (1), the cumene hydroperoxide and the solvent cumene are mixed to form a cumene hydroperoxide solution, and then added to the reaction system; the mass concentration of the cumene hydroperoxide solution is 24-88 wt%.

14. The continuous production process according to claim 13, characterized in that The mass concentration of the cumene hydroperoxide solution is 35-70 wt%.

15. The continuous production process according to claim 14, characterized in that The mass concentration of the cumene hydroperoxide solution is 50-60 wt%.

16. The continuous production process according to any one of claims 1-4, characterized in that, In step (1), the molar ratio of the cumene hydroperoxide to the α,α-dimethylbenzyl alcohol is (0.8-1.5):

1.

17. The continuous production process of claim 16, wherein, In step (1), the molar ratio of the cumene hydroperoxide to the α,α-dimethylbenzyl alcohol is (0.9-1.2):

1.

18. The continuous production process of claim 17, wherein, In step (1), the molar ratio of the cumene hydroperoxide to the α,α-dimethylbenzyl alcohol is (1.0-1.1):

1.

19. The continuous production process according to any one of claims 1-4, characterized in that, In step (1) and step (2), the acidic catalyst is independently selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and trichloroacetic acid.

20. The continuous production process of claim 19, wherein, In step (1) and step (2), the acidic catalyst is independently selected from one or more of sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid, and trichloroacetic acid.

21. The continuous production process according to claim 20, wherein, In step (1) and step (2), the acidic catalyst is independently selected from one or more of dodecylbenzenesulfonic acid or p-toluenesulfonic acid.

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