Preparation method of dicumyl peroxide

Abstract

The invention provides a preparation method of dicumyl peroxide. The preparation method comprises the following steps: under the conditions of an inhibitor and an acidic catalyst, cumyl hydroperoxide and alpha, alpha-dimethyl benzyl alcohol are subjected to a condensation reaction, and vacuum dehydration is carried out during the condensation reaction process. The combined inhibitor can greatly inhibit decomposition of dicumyl peroxide and dicumyl peroxide, and finally high conversion rate of raw materials, high selectivity of products and intrinsic safety of the reaction process are achieved. Wherein the conversion rate of the cumyl hydroperoxide is 99.5% or above, and the selectivity of the dicumyl peroxide is 98% or above.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and particularly relates to a method for preparing dicumyl peroxide. Background Art

[0002] Dicumyl peroxide is the 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 slightly yellow when exposed to light, theoretical active oxygen content 5.92%. Dicumyl peroxide can be used as a vulcanizing agent for natural rubber and synthetic rubber, such as ethylene propylene diene rubber (EPDM), nitrile rubber and silicone rubber. Dicumyl peroxide can also be used as an initiator for polymerization reactions and as a crosslinking agent for polyethylene resins, such as polyethylene (PE), chlorinated polyethylene (CPE), polystyrene (PS). Dicumyl peroxide can also be used as an initiator for the synthesis of expandable polystyrene (EPS), a foaming agent for polyethylene vinyl acetate (EVA), etc. After DCP crosslinking, the physical properties of the polymer are greatly improved, and its heat resistance, chemical resistance, pressure resistance, crack resistance and mechanical strength are all increased. DCP is widely used in wire and cable, shoemaking, building materials and other industries. In recent years, with the continuous expansion of the polymer materials market, the demand for DCP has increased year by year, and the market potential is huge.

[0003] At present, the industrial production of dicumyl peroxide adopts an intermittent reactor process, which uses cumene as raw material, oxidizes cumene into cumene hydroperoxide (CHP) through air oxidation, and reduces part of cumene hydroperoxide to generate α,α-dimethylbenzyl alcohol (DMBA), then condenses cumene hydroperoxide with α,α-dimethylbenzyl alcohol under the action of an acid catalyst to generate dicumyl peroxide (DCP), and then undergoes alkali washing, water washing and crystallization to obtain qualified products. The condensation reaction process is as follows:

[0004] Main reaction:

[0005]

[0006] Side effects:

[0007]

[0008] From the reaction process, it can be seen that the main reaction is a dehydration chemical equilibrium reaction process. During the condensation reaction, the main side reactions are DMBA dehydration to generate α-methylstyrene (AMS for short), CHP acid-catalyzed decomposition to generate phenol and acetone, DCP acid-catalyzed decomposition to generate phenol, acetone and DMBA, and then DMBA continues to acid-catalyzed dehydration to generate AMS, the byproduct phenol and AMS undergo alkylation reaction to generate 4-cumylphenol, and AMS self-polymerizes to generate dimers and trimers. The above decomposition reaction, alkylation reaction and polymerization reaction are all highly exothermic reactions, and once the reaction gets 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 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 material reaction is incomplete, affecting the product quality, and overreaction leads to secondary decomposition of DCP.

[0010] US4266081A discloses a method for preparing dicumyl peroxide using a strong acid and weak base salt (such as zinc chloride) as a catalyst. This patent has the problems that the catalyst is easily hydrolyzed, highly corrosive, and requires a large amount of catalyst.

[0011] US4413148A discloses a method for preparing diisopropylbenzene peroxide. The patent adopts a polar solvent such as triethyl phosphate which is hardly distilled away by water in the process of continuously removing the 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%. At the same time, there is a problem of large amount of high boiling point polar solvent added.

[0012] CN103145597B and CN104860861A disclose a method for producing dicumyl peroxide, which relates to a method for reducing byproducts in a condensation reaction of dicumyl peroxide. The patent adopts an intermittent production process, and the DCP selectivity is less than 94%, but there is still a problem of low DCP selectivity in the condensation reaction.

[0013] CN102827051A relates to a method for synthesizing dicumyl peroxide, and discloses a method for synthesizing dicumyl peroxide using refined benzyl alcohol and an oxidizing liquid as raw materials. Although the 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%, and there are problems such as low DCP product yield and high by-product content.

[0014] CN117690069A relates to a reaction method and device for dicumyl peroxide, in which the reaction liquid is circulated between the reactor and the film reactor, and the water generated during the reaction is removed by suction through a vacuum system connected to the reactor and the film reactor. This patent has the problems of narrow reaction temperature range control, poor DCP product selectivity, and high by-product content.

[0015] In summary, the current condensation process for the industrial production of dicumyl peroxide has problems such as large catalyst dosage, poor product selectivity, poor process controllability, low safety factor and / or low production efficiency. Summary of the invention

[0016] In view of the shortcomings of the prior art, one of the objects of the present invention is to provide a method for preparing dicumyl peroxide, which can achieve both high conversion rate of raw materials and high selectivity of products, and the reaction process is safe.

[0017] To achieve the purpose, the present invention provides the following technical solutions:

[0018] A method for preparing dicumyl peroxide comprises the following steps: in the presence of an inhibitor and an acidic catalyst, cumyl hydroperoxide and α,α-dimethylbenzyl alcohol undergo a condensation reaction, and vacuum dehydration is simultaneously performed during the condensation reaction.

[0019] The main reaction of the present invention 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, resulting in a slow reaction rate. In the condensation reaction process, the present invention removes the water produced by the reaction from the reaction system in a timely manner under vacuum to ensure a sufficient concentration of the acid catalyst to achieve the catalytic purpose. The reaction temperature control of the condensation reaction of CHP and DMBA to prepare DCP is extremely demanding. CHP and DCP are very likely to undergo secondary decomposition under the action of an acid catalyst, especially at the end of the reaction, when the conversion rate of CHP is greater than 95%, DCP is very likely to undergo secondary decomposition, resulting in over-temperature, over-pressure, and even explosion accidents.

[0020] The inventors found that the synergistic effect of the two inhibitors, organic polyphosphonic acid and imidazole compounds, terminated the free radical ROO · Decomposition and free radical C6H5(CH3)2CO ·The decomposition of CHP and DCP is particularly significant in the late stage of the reaction, when the CHP conversion rate is high and DCP is substantially not decomposed in the presence of an acidic catalyst, thereby ultimately achieving a high conversion rate of the raw materials, a high selectivity of the product and an intrinsic safety of the reaction process. Among them, the conversion rate of cumene hydroperoxide is above 99.5%, and the selectivity of dicumyl peroxide is above 98%. At the same time, since CHP and DCP are substantially not decomposed under the action of the combined inhibitor, the selection range of the raw material concentration of the present invention is relatively wide, the operating flexibility of the reaction temperature is large, and it is easy to control, which is conducive to realizing large-scale industrial production.

[0021] In one embodiment of the present invention, the inhibitor is a composition of an organic polyphosphonic acid and an imidazole compound; preferably, the organic polyphosphonic acid is selected from methylene and / or ethylene phosphonic acid, preferably one or more of aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylene phosphonic acid and diethylenetriaminepentamethylene phosphonic acid, more preferably aminotrimethylene phosphonic acid and / or hydroxyethylidene diphosphonic acid; preferably, the imidazole compound is selected from imidazole and its derivatives, preferably one or more of imidazole, methimidazole, 2-mercaptoimidazole, 2-mercaptobenzimidazole, more preferably imidazole and / or methimidazole; preferably, the mass ratio of the organic polyphosphonic acid to the imidazole compound in the inhibitor is 1:1-1:20, preferably 1:4-1:16, more preferably 1:8-1:12; preferably, based on the total mass of the cumene hydroperoxide, the amount of the combined inhibitor is 50-300 ppm, preferably 100-200 ppm, more preferably 120-160 ppm.

[0022] In one embodiment of the present invention, the acidic catalyst is selected from inorganic acid and / or organic acid, preferably one or more of sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and trichloroacetic acid, more preferably one or more of sulfuric acid, perchloric acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid; preferably, the amount of the acidic catalyst is 10-200ppm, preferably 50-150ppm, more preferably 80-120ppm, based on the total mass of cumene hydroperoxide. Preferably, the acidic catalyst is configured as an aqueous solution, preferably the mass concentration of the aqueous solution is 10-50wt%, more preferably 20-40wt%.

[0023] In one embodiment of the present invention, the molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol in the condensation reaction is (0.8-1.5):1, preferably (0.9-1.2):1, and more preferably (1.0-1.1):1.

[0024] In one embodiment of the present invention, cumene hydroperoxide is added to the reaction system in the form of a solution during the condensation reaction; preferably, the mass concentration of the cumene hydroperoxide solution is 24-88wt%, preferably 35-70wt%, more preferably 50-60wt%.

[0025] In one embodiment of the present invention, the reaction temperature of the condensation reaction is 30-70°C, preferably 40-60°C, more preferably 45-55°C.

[0026] In one embodiment of the present invention, the vacuum degree of the condensation reaction is 2-20 KPa, preferably 4-16 KPa, more preferably 8-12 KPa.

[0027] In one embodiment of the present invention, the reaction time of the condensation reaction is 1-6 h, preferably 2-5 h, more preferably 3-4 h.

[0028] Another object of the present invention is to provide a dicumyl peroxide.

[0029] A dicumyl peroxide is prepared by the above-mentioned preparation method.

[0030] The technical solution provided by the present invention has the following beneficial effects:

[0031] In the present invention, the conversion rate of cumene hydroperoxide is above 99.5%, and the selectivity of dicumyl peroxide is above 98%. At the same time, the selection range of the raw material concentration of the present invention is relatively wide, the operation flexibility of the reaction temperature is large, and it is easy to control, which is conducive to realizing industrialized large-scale production. DETAILED DESCRIPTION

[0032] In order to facilitate the understanding of the present invention, the present invention will be further described below in conjunction with examples. It should be understood that the following examples are only for a better understanding of the present invention and do not mean that the present invention is limited to the following examples.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which the invention belongs. The term "and / or" as may be used herein includes any and all combinations of one or more of the associated listed items.

[0034] The present invention is further illustrated below by means of specific examples, but it should not be understood that the present invention is limited thereto.

[0035] Where specific experimental steps or conditions are not specified in the examples, the corresponding conventional experimental steps or conditions in the art can be used. The reagents or instruments used without specifying the manufacturer are all conventional products that can be purchased commercially.

[0036] Cumene hydroperoxide solution: Wanhua Chemical Group Co., Ltd., mass concentration 24-88wt%;

[0037] α,α-Dimethylbenzyl alcohol: Aladdin Reagent (Shanghai) Co., Ltd., purity ≥99.0%.

[0038] The reaction conversion and selectivity were determined using liquid chromatography external standard curve analysis.

[0039] The chromatographic analysis conditions are as follows: Shimadzu liquid chromatography SPD-20A; column oven: CT0-10ASvp; column temperature: 35°C, chromatographic column is T3 column, mobile phase is water and acetonitrile, water / acetonitrile = 25:75 (vol / vol), total flow rate is 1 ml / min, residence time is 40 min, and detector wavelength is 254 nm.

[0040] The ppm mentioned are all mass ppm.

[0041] Example 1

[0042] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 50wt% cumene hydroperoxide solution (the solvent is cumene), aminotrimethylphosphonic acid and imidazole combined inhibitor and 25wt% p-toluenesulfonic acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 45°C and a vacuum degree of 8KPa for 2h. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 100%, and the selectivity of dicumyl peroxide was 99.6%. 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 80ppm, the amount of aminotrimethylphosphonic acid and methylimidazole combined inhibitor was 120ppm, and the mass ratio of aminotrimethylphosphonic acid to methylimidazole was 1:8.

[0043] Example 2

[0044] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 60wt% cumene hydroperoxide solution (the solvent is cumene), hydroxyethylidene diphosphonic acid and imidazole combined inhibitor and 30wt% dodecylbenzene sulfonic acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 55°C and a vacuum degree of 12KPa for 5 hours. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 100%, and the selectivity of dicumyl peroxide was 99.5%. Among them, the molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 1.1:1; based on the total mass of cumene hydroperoxide, the amount of dodecylbenzene sulfonic acid was 120ppm, the amount of hydroxyethylidene diphosphonic acid and imidazole combined inhibitor was 160ppm, and the mass ratio of hydroxyethylidene diphosphonic acid to imidazole was 1:12.

[0045] Example 3

[0046] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 35wt% cumene hydroperoxide solution (the solvent is cumene), aminotrimethylphosphonic acid and imidazole combined inhibitor and 50wt% dodecylbenzenesulfonic acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 40°C and a vacuum degree of 4KPa for 3 hours. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 99.8%, and the selectivity of dicumyl peroxide was 99.0%. 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 sulfuric acid was 150ppm, the amount of aminotrimethylphosphonic acid and imidazole combined inhibitor was 200ppm, and the mass ratio of aminotrimethylphosphonic acid to imidazole was 1:4.

[0047] Example 4

[0048] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 70wt% cumene hydroperoxide solution (the solvent is cumene), hydroxyethylidene diphosphonic acid and methimazole combined inhibitor and 10wt% perchloric acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 60°C and a vacuum degree of 16KPa for 4 hours. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 99.7%, and the selectivity of dicumyl peroxide was 99.3%. Among them, the molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 1.2:1; based on the total mass of cumene hydroperoxide, the amount of perchloric acid was 200ppm, the amount of hydroxyethylidene diphosphonic acid and methimazole combined inhibitor was 100ppm, and the mass ratio of hydroxyethylidene diphosphonic acid to methimazole was 1:16.

[0049] Example 5

[0050] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 24wt% cumene hydroperoxide solution (the solvent is cumene), aminotrimethylphosphonic acid and imidazole combined inhibitor and 40wt% perchloric acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 70°C and a vacuum degree of 20KPa for 1h. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 99.8%, and the selectivity of dicumyl peroxide was 98.1%. Among them, the molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 1.5:1; based on the total mass of cumene hydroperoxide, the amount of perchloric acid was 10ppm, the amount of aminotrimethylphosphonic acid and imidazole combined inhibitor was 50ppm, and the mass ratio of aminotrimethylphosphonic acid to imidazole was 1:1.

[0051] Example 6

[0052] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 88wt% cumene hydroperoxide solution (the solvent is cumene), ethylenediaminetetramethylenephosphonic acid and imidazole combined inhibitor and 20wt% p-toluenesulfonic acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 30°C and a vacuum degree of 2KPa for 6 hours. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 99.6%, and the selectivity of dicumyl peroxide was 98.5%. Among them, the molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 0.8:1; based on the total mass of cumene hydroperoxide, the amount of p-toluenesulfonic acid was 50ppm, the amount of ethylenediaminetetramethylenephosphonic acid and imidazole combined inhibitor was 300ppm, and the mass ratio of ethylenediaminetetramethylenephosphonic acid to imidazole was 1:20.

[0053] Example 7

[0054] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 50wt% cumene hydroperoxide solution (the solvent is cumene), aminotrimethylphosphonic acid and 2-mercaptoimidazole combined inhibitor and 25wt% phosphoric acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 45°C and a vacuum degree of 8KPa for 2h. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 99.5%, and the selectivity of dicumyl peroxide was 98.1%. 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 phosphoric acid was 80ppm, the amount of aminotrimethylphosphonic acid and 2-mercaptoimidazole combined inhibitor was 120ppm, and the mass ratio of aminotrimethylphosphonic acid to 2-mercaptoimidazole was 1:8.

[0055] Example 8

[0056] Under stirring conditions, 99.9% purity α,α-dimethylbenzyl alcohol, 60wt% cumene hydroperoxide solution (the solvent is cumene), ethylenediaminetetramethylenephosphonic acid and methimazole combined inhibitor and 30wt% dodecylbenzenesulfonic acid aqueous solution were added to a 1L autoclave in sequence, and the reaction was carried out at a reaction temperature of 55°C and a vacuum degree of 12KPa for 5 hours. According to liquid chromatography analysis, the conversion rate of cumene hydroperoxide was 99.7%, and the selectivity of dicumyl peroxide was 98.2%. Among them, the molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol was 1.1:1; based on the total mass of cumene hydroperoxide, the amount of dodecylbenzenesulfonic acid was 120ppm, the amount of ethylenediaminetetramethylenephosphonic acid and methimazole combined inhibitor was 160ppm, and the mass ratio of ethylenediaminetetramethylenephosphonic acid to methimazole was 1:12.

[0057] Comparative Example 1

[0058] Compared with Example 1, under the same other conditions, aminotrimethylphosphonic acid was not added.

[0059] According to the analysis of liquid chromatography, the conversion rate of cumene hydroperoxide was 100%, and the selectivity of dicumyl peroxide was 93.5%.

[0060] Comparative Example 2

[0061] Compared with Example 1, under the same other conditions, methimazole was not added.

[0062] According to the analysis of liquid chromatography, the conversion rate of cumene hydroperoxide was 99.5%, and the selectivity of dicumyl peroxide was 89.6%.

[0063] Comparative Example 3

[0064] Compared with Example 1, under the same other conditions, aminotrimethylphosphonic acid and methimazole inhibitor were not added.

[0065] According to the analysis of liquid chromatography, the conversion rate of cumene hydroperoxide was 98.0%, and the selectivity of dicumyl peroxide was 78.6%.

[0066] It is easy to understand that the above embodiments are only examples for clear explanation and do not mean that the present invention is limited thereto. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived from this are still within the protection scope of the present invention.

Claims

1. A method for preparing dicumyl peroxide, characterized in that: In the preparation method, cumene hydroperoxide and α,α-dimethylbenzyl alcohol undergo a condensation reaction under the conditions of an inhibitor and an acidic catalyst, and vacuum dehydration is simultaneously performed during the condensation reaction.

2. The preparation method according to claim 1, characterized in that: The inhibitor is a combination of an organic polyphosphonic acid and an imidazole compound; Preferably, the organic polyphosphonic acid is selected from methylene and / or ethylene phosphonic acid, preferably one or more of aminotrimethylene phosphonic acid, hydroxyethylidene diphosphonic acid, ethylenediaminetetramethylene phosphonic acid and diethylenetriaminepentamethylene phosphonic acid, more preferably aminotrimethylene phosphonic acid and / or hydroxyethylidene diphosphonic acid; Preferably, the imidazole compound is selected from imidazole and its derivatives, preferably one or more of imidazole, methimazole, 2-mercaptoimidazole, 2-mercaptobenzimidazole, more preferably imidazole and / or methimazole; Preferably, the mass ratio of the organic polyphosphonic acid to the imidazole compound in the inhibitor is 1:1-1:20, preferably 1:4-1:16, more preferably 1:8-1:12; Preferably, based on the total mass of the cumene hydroperoxide, the combined inhibitor is used in an amount of 50-300 ppm, preferably 100-200 ppm, more preferably 120-160 ppm.

3. The preparation method according to claim 1 or 2, characterized in that: The acidic catalyst is selected from inorganic acids and / or organic acids, preferably one or more of sulfuric acid, hydrochloric acid, phosphoric acid, perchloric acid, p-toluenesulfonic acid, dodecylbenzenesulfonic acid and trichloroacetic acid, more preferably one or more of sulfuric acid, perchloric acid, p-toluenesulfonic acid and dodecylbenzenesulfonic acid; Preferably, the acidic catalyst is used in an amount of 10-200 ppm, preferably 50-150 ppm, more preferably 80-120 ppm, based on the total mass of cumene hydroperoxide.

4. The preparation method according to any one of claims 1 to 3, characterized in that The molar ratio of cumene hydroperoxide to α,α-dimethylbenzyl alcohol in the condensation reaction is (0.8-1.5):1, preferably (0.9-1.2):1, more preferably (1.0-1.1):1; and / or, in the condensation reaction, cumene hydroperoxide is added to the reaction system in the form of a solution; Preferably, the mass concentration of the cumene hydroperoxide solution is 24-88wt%, preferably 35-70wt%, more preferably 50-60wt%; and / or, the reaction temperature of the condensation reaction is 30-70°C, preferably 40-60°C, more preferably 45-55°C; And / or, the vacuum degree of the condensation reaction is 2-20 KPa, preferably 4-16 KPa, more preferably 8-12 KPa; And / or, the reaction time of the condensation reaction is 1-6 h, preferably 2-5 h, more preferably 3-4 h.

5. A dicumyl peroxide, wherein the dicumyl peroxide is prepared by the preparation method according to any one of claims 1 to 4.

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