A preparation method of methyl ethyl ketone peroxide with low water content

Abstract

The present invention relates to the technical field of the preparation of methyl ethyl ketone peroxide, and particularly relates to a preparation method of methyl ethyl ketone peroxide with low water content, which comprises the following steps: (1) adding hydrogen peroxide into a reaction kettle, adding a catalyst and stirring evenly, and then slowly dropping methyl ethyl ketone into the reaction kettle under stirring, and carrying out a reaction after the dropping is completed; (2) after the reaction is completed, adding a water separator into the reaction mixture, standing for stratification, and taking the upper-layer liquid; (3) freezing the upper-layer liquid, filtering the frozen liquid, and adding dimethyl phthalate into the filtrate for dilution to obtain the product. In the preparation method of methyl ethyl ketone peroxide with low water content of the present invention, by adding a freezing treatment process, the synthesized methyl ethyl ketone peroxide is frozen at -30 to -50 °C, greatly reducing the water content of methyl ethyl ketone peroxide. The water content of the prepared methyl ethyl ketone peroxide product is 4-5%, and the active oxygen content is 8-9%. The reaction performance and curing performance are good, and it has high production application value.

Description

Technical Field

[0001] The present invention relates to the technical field of the preparation of methyl ethyl ketone peroxide, and particularly relates to a method for preparing methyl ethyl ketone peroxide with low water content. Background Art

[0002] Organic peroxides are organic substances containing a divalent -O-O- structure after the hydrogen atoms in H2O2 are replaced by organic groups such as alkyl groups, acyl groups, and ketone groups. The chemical general formula is R1-O-O-R2, and generally has the following properties: having strong oxidizing properties; decomposing when heated; decomposing when encountering acids, alkalis, and metals; decomposing when encountering reducing agents; promoting decomposition by rubber; being extremely sensitive to friction and vibration, etc. The -O-O- bond in organic peroxides is long and weak, and is easily decomposed by heat, doping with acids and bases, metals, etc., generating ·O- free radicals and releasing a large amount of heat. In industry, organic peroxides are commonly used as oxidants, initiators, curing agents, and cross-linking agents; they are also important pharmaceutical raw materials and intermediates in medicine.

[0003] Methyl ethyl ketone peroxide (MEKP), also known as 2-butanone peroxide, has the molecular formula C8H 18 O6 and belongs to ketone peroxides. Methyl ethyl ketone peroxide has the advantages of low price, good performance, stability at room temperature, convenient use, easy mixing with resins, etc. It is widely used as an initiator for unsaturated resins, and also as an initiator, bleaching agent, fungicide, etc. in organic synthesis. It is one of the most widely used organic peroxides in the world. The activity of methyl ethyl ketone peroxide is mainly measured by a specific active oxygen content. The higher the active oxygen content, the greater its activity, but the higher the risk. Therefore, considering comprehensive safety and market application value, it is generally required to control the active oxygen content of methyl ethyl ketone peroxide within 8-10%. The active components of methyl ethyl ketone peroxide are three: (a) hydrogen peroxide and its derivatives, which only affect the gel process of the resin; (b) MEKP in monomer form, which affects the gel process to a lesser extent but affects the initial curing speed to a greater extent; (c) the dimer form of MEKP, which affects the gel process to a relatively smaller extent but greatly affects the entire curing and post-curing processes.

[0004] The main raw materials for preparing methyl ethyl ketone peroxide are hydrogen peroxide and butanone. Since a large amount of water is contained in hydrogen peroxide, the residual water in methyl ethyl ketone peroxide will cause abnormalities when it is used as a curing agent to cure the resin, such as rapid gelation in the early stage and delayed curing in the later stage, seriously affecting the strength of the resin product, and generating water mist and bubbles, resulting in cloud-like patches in transparent products and polyester paint films, causing quality defects. Therefore, in the production process of methyl ethyl ketone peroxide, in addition to the conventional synthesis steps, a dehydration step is usually included, and the water content of methyl ethyl ketone peroxide has become a key index for distinguishing high-quality and safe methyl ethyl ketone peroxide from low-quality and dangerous methyl ethyl ketone peroxide.

[0005] Since some products of methyl ethyl ketone peroxide are miscible with water and the water in the products cannot be completely removed, the water content of methyl ethyl ketone peroxide prepared by the existing process is usually above 10%. For example, Chinese Patent Application CN114349675A discloses a continuous synthesis method of methyl ethyl ketone peroxide, and the water content of the methyl ethyl ketone peroxide prepared by this method is 13%, which cannot meet the requirements of low water content methyl ethyl ketone peroxide. Therefore, providing a preparation method of low water content methyl ethyl ketone peroxide is a technical problem that those skilled in the art urgently need to solve. Summary of the Invention

[0006] In order to solve the above problems, the present invention provides a preparation method of low water content methyl ethyl ketone peroxide, adopting a low-temperature freezing technology, which greatly reduces the water content of methyl ethyl ketone peroxide.

[0007] A preparation method of low water content methyl ethyl ketone peroxide includes the following steps:

[0008] (1) Add hydrogen peroxide to the reaction kettle, add a catalyst and stir evenly, then slowly drop methyl ethyl ketone into the reaction kettle under stirring for reaction. After the dropping is completed, continue the reaction for 1 hour;

[0009] (2) After the reaction is completed, add a water separator to the reaction mixture, let it stand for stratification, and take the upper layer liquid;

[0010] (3) Freeze the upper layer liquid, filter the frozen liquid, and add dimethyl phthalate to the filtrate for dilution to obtain the product.

[0011] Further, in step (1), the reaction kettle is a jacketed reaction kettle, and cooling water is passed through the jacket of the jacketed reaction kettle.

[0012] Further, the temperature of the cooling water is 8-10°C.

[0013] Further, in step (1), the hydrogen peroxide is hydrogen peroxide with a mass fraction of 50%, the mass ratio of the hydrogen peroxide to the methyl ethyl ketone is 1.2-1.8:1.0, and the mass ratio of the hydrogen peroxide to the catalyst is 100:1.

[0014] Further, the catalyst in step (1) is sulfuric acid.

[0015] Further, the dropping time of methyl ethyl ketone in step (1) is 30 min, and the reaction time is 1 h.

[0016] Further, the reaction temperature in step (1) is 20-28°C

[0017] Further, the water separator described in step (2) is anhydrous sodium sulfate. Using anhydrous sodium sulfate as the water separator, anhydrous sodium sulfate does not participate in the reaction in the system, is easy to remove and will not introduce impurities. At the same time, it also has a salting-out effect, which is used to increase the specific gravity of the water layer, accelerate the layering rate, thereby enhancing the water separation effect, and further reducing the water content of methyl ethyl ketone peroxide.

[0018] Further, in step (3), the freezing temperature is -30 to -50 °C, and the freezing time is 2 to 3 h.

[0019] After the synthesized methyl ethyl ketone peroxide is separated from water by layering, there is still a part of water that is difficult to remove. Using the freezing method, the material obtained in the reaction process is frozen to -30 to -50 °C. At low temperature, part of the water in methyl ethyl ketone peroxide will crystallize out. After filtering the crystal water, a methyl ethyl ketone peroxide product with low water content can be obtained.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] (1) The preparation method of a low-water-content methyl ethyl ketone peroxide of the present invention adds a freezing treatment process. The synthesized methyl ethyl ketone peroxide is frozen at -30 to -50 °C, so that part of the water in it crystallizes out. By filtering to remove this part of crystal water, the water content in the prepared methyl ethyl ketone peroxide is further reduced, meeting the requirements of low-water-content methyl ethyl ketone peroxide. The water content of the prepared methyl ethyl ketone peroxide product is 4-5%, and the active oxygen content is 8-9%. That is, it ensures the reaction activity of the methyl ethyl ketone peroxide product and the curing performance of the product, and has good application value.

[0022] (2) The preparation method of a low-water-content methyl ethyl ketone peroxide of the present invention adopts a step-by-step water removal process. First, anhydrous sodium sulfate is used as the water separator in the water separation process to quickly separate and remove most of the water by layering, and then the freezing method is used to remove the remaining water. The water separation process is combined with the freezing water removal technology, achieving a good effect of greatly reducing the water content of methyl ethyl ketone peroxide on the basis of ensuring production efficiency and production cost, meeting the needs of market customers.

[0023] (3) The preparation method of a low-water-content methyl ethyl ketone peroxide of the present invention is simple in operation, does not require adding new equipment and raw material additives, has low cost, is applicable to the conventional methyl ethyl ketone peroxide preparation system, and is suitable for popularization and application. Specific Embodiments

[0024] For the experimental methods without specific conditions in the following embodiments of the present invention, they are usually carried out under conventional conditions or according to the conditions recommended by the manufacturer. All kinds of commonly used chemical reagents used in the embodiments are commercially available products.

[0025] Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the technical field to which the present invention pertains. The terms used in the description of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0026] The terms "comprising" and "having" and any variations thereof in the present invention are intended to cover non-exclusive inclusion. For example, a process, method, apparatus, product or device that includes a series of steps is not limited to the listed steps or modules, but optionally further includes steps not listed, or optionally further includes other steps inherent to these processes, methods, products or devices.

[0027] As used in the present invention, "a plurality of" means two or more. "And / or" describes the relationship between associated objects and indicates that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. The character " / " generally indicates an "or" relationship between the associated objects before and after.

[0028] The technical solutions of the present invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts belong to the protection scope of the present invention.

[0029] Example 1

[0030] A method for preparing methyl ethyl ketone peroxide with low water content, comprising the following steps:

[0031] (1) Add 425 g of 50% hydrogen peroxide to a reaction kettle with a jacket for cooling, turn on the stirrer, and pass 10°C cooling water into the jacket to cool the material. Then add 4 g of sulfuric acid to the reaction kettle, stir evenly, slowly drop 300 g of butanone, and finish dropping in 30 minutes. Then keep the temperature of the reaction material at 20°C and react for 1 h;

[0032] (2) After the reaction is completed, add 5 g of anhydrous sodium sulfate to the reaction mixture, let it stand for 1 h, and take the upper layer liquid;

[0033] (3) Place the upper layer liquid in a -40°C freezer and freeze for 2 h. Then filter the frozen liquid, and add 400 g of dimethyl phthalate to the filtrate for dilution to obtain the methyl ethyl ketone peroxide product.

[0034] Example 2

[0035] A method for preparing methyl ethyl ketone peroxide with low water content, comprising the following steps:

[0036] (1) Add 380 g of 50% hydrogen peroxide solution into a reaction kettle equipped with a jacket for cooling. Turn on the stirrer, and introduce 9°C cooling water into the jacket to cool the materials. Then add 3.8 g of sulfuric acid into the reaction kettle, stir evenly, slowly drop in 300 g of methyl ethyl ketone, and finish dropping within 30 min. Then maintain the temperature of the reaction materials at 25°C and react for 1 h.

[0037] (2) After the reaction is completed, add 8 g of anhydrous sodium sulfate into the reaction mixture, let it stand for 1 h, and take the upper-layer liquid.

[0038] (3) Place the upper-layer liquid in a freezer at -30°C for 3 h, then filter the frozen liquid, and add 400 g of dimethyl phthalate into the filtrate for dilution to obtain the methyl ethyl ketone peroxide product.

[0039] Example 3

[0040] A preparation method of methyl ethyl ketone peroxide with low water content, comprising the following steps:

[0041] (1) Add 500 g of 50% hydrogen peroxide solution into a reaction kettle equipped with a jacket for cooling. Turn on the stirrer, and introduce 10°C cooling water into the jacket to cool the materials. Then add 5 g of sulfuric acid into the reaction kettle, stir evenly, slowly drop in 300 g of methyl ethyl ketone, and finish dropping within 30 min. Then maintain the temperature of the reaction materials at 28°C and react for 1 h.

[0042] (2) After the reaction is completed, add 15 g of anhydrous sodium sulfate into the reaction mixture, let it stand for 1 h, and take the upper-layer liquid.

[0043] (3) Place the upper-layer liquid in a freezer at -50°C for 2.5 h, then filter the frozen liquid, and add 400 g of dimethyl phthalate into the filtrate for dilution to obtain the methyl ethyl ketone peroxide product.

[0044] Comparative Example 1

[0045] The difference between this comparative example and Example 1 is that no water separator is added. The specific steps are as follows:

[0046] (1) Add 425 g of 50% hydrogen peroxide solution into a reaction kettle equipped with a jacket for cooling. Turn on the stirrer, and introduce 10°C cooling water into the jacket to cool the materials. Then add 4 g of sulfuric acid into the reaction kettle, stir evenly, slowly drop in 300 g of methyl ethyl ketone, and finish dropping within 30 min. Then maintain the temperature of the reaction materials at 20°C and react for 1 h.

[0047] (2) After the reaction is completed, place the reaction mixture in a freezer at -40°C for 2 h, then filter the frozen liquid, and add 400 g of dimethyl phthalate into the filtrate for dilution to obtain the methyl ethyl ketone peroxide product.

[0048] Comparative Example 2

[0049] The difference between this comparative example and Example 1 is that sodium chloride is used as the water separator, and the specific steps are as follows:

[0050] (1) Add 425 g of 50% hydrogen peroxide to a reaction kettle with a jacket for cooling, turn on the stirring, and pass 10°C cooling water into the jacket to cool the material. Then add 4 g of sulfuric acid to the reaction kettle, stir evenly, slowly drop 300 g of methyl ethyl ketone, and finish dropping in 30 min. Then keep the temperature of the reaction material at 20°C and react for 1 h;

[0051] (2) After the reaction is completed, add 5 g of sodium chloride to the reaction mixture, let it stand for 1 h, and take the upper layer liquid;

[0052] (3) Place the upper layer liquid in a -40°C freezer and freeze for 2 h. Then filter the frozen liquid, and add 400 g of dimethyl phthalate to the filtrate for dilution to obtain the methyl ethyl ketone peroxide product.

[0053] Comparative Example 3

[0054] The difference between this comparative example and Example 1 is that no freezing treatment is carried out, and the specific steps are as follows:

[0055] (1) Add 425 g of 50% hydrogen peroxide to a reaction kettle with a jacket for cooling, turn on the stirring, and pass 10°C cooling water into the jacket to cool the material. Then add 4 g of sulfuric acid to the reaction kettle, stir evenly, slowly drop 300 g of methyl ethyl ketone, and finish dropping in 30 min. Then keep the temperature of the reaction material at 20°C and react for 1 h;

[0056] (2) After the reaction is completed, add 5 g of anhydrous sodium sulfate to the reaction mixture, let it stand for 1 h, take the upper layer liquid, and add 400 g of dimethyl phthalate to it for dilution to obtain the methyl ethyl ketone peroxide product.

[0057] Comparative Example 4

[0058] The difference between this comparative example and Example 2 is that no freezing treatment is carried out, and the specific steps are as follows:

[0059] (1) Add 380 g of 50% hydrogen peroxide to a reaction kettle with a jacket for cooling, turn on the stirring, and pass 9°C cooling water into the jacket to cool the material. Then add 3.8 g of sulfuric acid to the reaction kettle, stir evenly, slowly drop 300 g of methyl ethyl ketone, and finish dropping in 30 min. Then keep the temperature of the reaction material at 25°C and react for 1 h;

[0060] (2) After the reaction is completed, 8 g of anhydrous sodium sulfate is added to the reaction mixture, and it is allowed to stand for 1 h. The upper layer of liquid is taken, and 400 g of dimethyl phthalate is added thereto for dilution, thus obtaining the methyl ethyl ketone peroxide product.

[0061] Comparative Example 5

[0062] The difference between this comparative example and Example 3 is that no freezing treatment is carried out. The specific steps are as follows:

[0063] (1) 500 g of 50% hydrogen peroxide is added to a reaction kettle with a jacket for cooling. The stirring is turned on, and 10°C cooling water is passed through the jacket to cool the material. Then 5 g of sulfuric acid is added to the reaction kettle, stirred evenly, and 300 g of butanone is slowly dropped in. The dropping is completed in 30 min, and then the temperature of the reaction material is maintained at 28°C for 1 h of reaction;

[0064] (2) After the reaction is completed, 15 g of anhydrous sodium sulfate is added to the reaction mixture, and it is allowed to stand for 1 h. The upper layer of liquid is taken, and 400 g of dimethyl phthalate is added thereto for dilution, thus obtaining the methyl ethyl ketone peroxide product.

[0065] Comparative Example 6

[0066] The difference between this comparative example and Example 1 is that the freezing temperature is -20°C. The specific steps are as follows:

[0067] (1) 425 g of 50% hydrogen peroxide is added to a reaction kettle with a jacket for cooling. The stirring is turned on, and 10°C cooling water is passed through the jacket to cool the material. Then 4 g of sulfuric acid is added to the reaction kettle, stirred evenly, and 300 g of butanone is slowly dropped in. The dropping is completed in 30 min, and then the temperature of the reaction material is maintained at 20°C for 1 h of reaction;

[0068] (2) After the reaction is completed, 5 g of anhydrous sodium sulfate is added to the reaction mixture, and it is allowed to stand for 1 h. The upper layer of liquid is taken;

[0069] (3) The upper layer of liquid is placed in a -20°C freezer for 2 h, and then the frozen liquid is filtered. 400 g of dimethyl phthalate is added to the filtrate for dilution, thus obtaining the methyl ethyl ketone peroxide product.

[0070] Comparative Example 7

[0071] The difference between this comparative example and Example 1 is that the freezing temperature is -60°C. The specific steps are as follows:

[0072] (1) Add 425 g of 50% hydrogen peroxide to a reaction kettle with a jacket for cooling. Turn on the stirrer and introduce 10°C cooling water into the jacket to cool the material. Then add 4 g of sulfuric acid to the reaction kettle, stir evenly, and slowly drip 300 g of methyl ethyl ketone. The dropping is completed in 30 min. Then maintain the temperature of the reaction material at 20°C and react for 1 h;

[0073] (2) After the reaction is completed, add 5 g of anhydrous sodium sulfate to the reaction mixture, let it stand for 1 h, and take the upper layer liquid;

[0074] (3) Place the upper layer liquid in a -20°C freezer for 2 h, then filter the frozen liquid, and add 400 g of dimethyl phthalate to the filtrate for dilution to obtain the methyl ethyl ketone peroxide product.

[0075] Perform performance tests on the methyl ethyl ketone peroxide products prepared in Examples 1-3 and Comparative Examples 1-7. The relevant test methods are as follows:

[0076] Ⅰ. Determination of active oxygen content: Adopt GB / T32102-2015 "Determination of Organic Peroxide Content - Iodometric Method". Adopt the potassium iodide - room temperature detection method. Dissolve the sample in a mixed solution of dichloromethane and glacial acetic acid, add saturated potassium iodide solution. The organic peroxide reacts with the potassium iodide solution to generate iodine, and the iodine reacts with a quantitative sodium thiosulfate standard solution and is reduced again. According to the volume of the sodium thiosulfate standard titration solution consumed, calculate the active oxygen content of the organic peroxide.

[0077] Ⅱ. Determination of water content: Adopt GB / T6283-2008 "Determination of Water Content in Chemical Products - Karl Fischer Method (General Method)". Adopt A / B dual-component Karl Fischer reagent. A is Karl Fischer solution (pyridine-free organic base, sulfur dioxide, methanol solution), B is Karl Fischer titrant (iodine, methanol solution), and determine by direct coulometric titration method.

[0078] Among them, since the active oxygen content and water content of methyl ethyl ketone peroxide are two interrelated indicators, the comparison of water content is based on the same active oxygen content of the final product. The active oxygen contents of the methyl ethyl ketone peroxide products prepared by different experimental schemes are different. Therefore, it is necessary to dilute the product with a solvent to ensure that the active oxygen content is the same and meets the standard (below 10%), and then conduct the final measurement and comparison of the water content. In the present invention, the solvent is used to adjust the active oxygen content of Examples 1-3 and Comparative Examples 1-7 to 8.8%, and then measure and compare the water content data.

[0079] The test results are shown in Table 1.

[0080] Table 1

[0081] Appearance Active oxygen content / % Water content / % Example 1 Colorless and transparent 8.8 4.4 Example 2 Colorless and transparent 8.8 4.6 Example 3 Colorless and transparent 8.8 4.3 Comparative Example 1 Colorless and transparent 8.8 12.3 Comparative Example 2 Colorless and transparent 8.8 5.8 Comparative Example 3 Colorless and transparent 8.8 12.1 Comparative Example 4 Colorless and transparent 8.8 13.2 Comparative Example 5 Colorless and transparent 8.8 11.3 Comparative Example 6 Colorless and transparent 8.8 7.6 Comparative Example 7 Colorless and transparent 8.8 4.0

[0082] As can be seen from Table 1, in Examples 1-3, the preparation method of the present invention is adopted. After synthesizing methyl ethyl ketone peroxide, through the water separation process and the freezing water removal process, the water content in the prepared methyl ethyl ketone peroxide product is greatly reduced. The active oxygen content of the methyl ethyl ketone peroxide prepared by the present invention is 8.7-8.8%, and the water content is only 4.3-4.6%. In Comparative Example 1, only the freezing method is used to remove water without performing the water separation operation. The water content in the methyl ethyl ketone peroxide entering the freezer is relatively high and it is difficult to remove by the freezing method. In Comparative Example 2, sodium chloride is selected as the water separation agent, and the water separation effect is slightly worse than that of sodium sulfate. Moreover, chloride ion impurities are introduced into the product and are not easy to remove, resulting in a decrease in product purity and an increase in the difficulty of wastewater treatment, not meeting the environmental protection requirements. Compared with Examples 1-3, in Comparative Examples 3-5, the freezing water removal process is not adopted, and the water that is difficult to remove only by the water separation step remains in the product, resulting in a relatively high water content in the methyl ethyl ketone peroxide. In Comparative Examples 6-7, the freezing water removal is carried out at -20°C and -60°C respectively. Although the temperatures of both are lower than the freezing point of water, due to the residual water in the methyl ethyl ketone peroxide after water separation being mixed with the methyl ethyl ketone peroxide, and the two appearing in a mixture state and influencing each other, the actual crystallization performance of the residual water changes. It is difficult to remove completely at -20°C, and the water content of the product is still relatively high. In Comparative Example 7, the freezing temperature is further reduced, but compared with Examples 1-3, the water content of the product does not change significantly, which will cause an increase in operation difficulty and production energy consumption, and may reach the crystallization point of other component materials in the product, causing a change in the component ratio of the product, resulting in an increase in the uncertainty of the product.

[0083] In summary, the present application adopts the cold water removal process, combined with the water separation step at a specific freezing temperature, to achieve a significant reduction in the water content of the methyl ethyl ketone peroxide product, and the operation is simple, environmentally friendly and energy consumption is low, which is suitable for popularization and application.

[0084] The above further describes the present invention with the help of specific embodiments. However, it should be understood that the specific description here should not be construed as a limitation on the essence and scope of the present invention. Various modifications made by those of ordinary skill in the art to the above embodiments after reading this specification all fall within the scope protected by the present invention.

Claims

1. A preparation method of methyl ethyl ketone peroxide with low water content, characterized in that, It includes the following steps: (1) Add hydrogen peroxide into the reaction kettle, add the catalyst and stir evenly, then slowly dropwise add methyl ethyl ketone into the reaction kettle under stirring for reaction. After the dropping is completed, continue the reaction for 1 hour; (2) After the reaction is completed, add a water separator to the reaction mixture, let it stand for stratification, and take the upper layer liquid; (3) Freeze the upper layer liquid, filter the frozen liquid, and add dimethyl phthalate to the filtrate for dilution to obtain the product; In step (1), the hydrogen peroxide is hydrogen peroxide with a mass fraction of 50%. The mass ratio of the hydrogen peroxide to the methyl ethyl ketone is 1.2 - 1.8:1.0, and the mass ratio of the hydrogen peroxide to the catalyst is 100:

1. The catalyst is sulfuric acid; In step (2), the water separator is anhydrous sodium sulfate; In step (3), the freezing temperature is -30 to -50 °C, and the freezing time is 2 - 3 h.

2. The preparation method of a methyl ethyl ketone peroxide with low water content according to claim 1, characterized in that, In step (1), the reaction kettle is a jacketed reaction kettle, and cooling water is passed through the jacket of the jacketed reaction kettle.

3. A preparation method of methyl ethyl ketone peroxide with low water content according to claim 2, characterized in that, The temperature of the cooling water is 8 - 10 °C.

4. A method for preparing methyl ethyl ketone peroxide with low water content according to claim 1, characterized in that, In step (1), the dropping time of methyl ethyl ketone is 30 min, and the reaction time is 1 h.

5. A preparation method of methyl ethyl ketone peroxide with low water content according to claim 1, characterized in that, In step (1), the reaction temperature is 20 - 28 °C.