Synthetic method of methyl ethyl ketazine

Abstract

The invention provides a synthetic method of methyl ethyl ketazine. According to the synthetic method, a nonionic surfactant is introduced into a traditional hydrogen peroxide method reaction system; the specific reaction system comprises raw materials, a catalyst, an oxidizing agent and an auxiliary agent, wherein the raw materials comprise butanone and ammonia water, the oxidizing agent is hydrogen peroxide, the catalyst is an amide compound, the auxiliary agent is a nonionic surfactant, and preferably, EDTA disodium can be introduced into the hydrogen peroxide. By introducing the auxiliary agent to modulate the reaction system environment, the effective contact area between the reaction materials can be greatly increased, the synthesis reaction is ensured to be more uniform and rapid, the reaction temperature for synthesizing the methyl ethyl ketazine can be reduced, the energy consumption is reduced, and the effects of improving the reaction efficiency and the yield of the methyl ethyl ketazine are also achieved.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis and mainly relates to a method for synthesizing butanone azine and hydrazine hydrate. Background Art

[0002] Ketazine is an intermediate in the preparation of hydrazine hydrate. Hydrazine hydrate and the corresponding ketone can be obtained through the hydrolysis reaction of ketazine. Hydrazine hydrate, also known as hydrated hydrazine, is a colorless oily liquid with a light ammonia smell. It is a widely used chemical raw material and an important chemical product. In the pharmaceutical industry, it is often used to produce anti-tuberculosis, anti-diabetic and other drugs; in pesticide synthesis, it is used to produce herbicides, plant growth regulators, and insecticides and fungicides; in the chemical industry, it is used to produce various foaming agents, boiler or reactor cleaning agents; high-concentration hydrazine hydrate is mainly used in the military industry for the production of rocket fuels and energetic materials.

[0003] There are four main industrial production methods for hydrazine hydrate, namely, the Raschig process, the urea process, the ketazine process and the hydrogen peroxide process. Among them, the Raschig process is to use chlorine to pass through a supersaturated sodium hydroxide solution to prepare sodium hypochlorite, and use it as an oxidant to oxidize ammonia to obtain a low-concentration hydrazine hydrate solution. This method not only has a low product yield (65%, calculated as sodium hypochlorite), but also has high energy consumption, and has now been eliminated. The urea process uses urea as a nitrogen source, and undergoes an oxidation reaction with sodium hypochlorite to generate hydrazine hydrate, with a yield of about 70% (calculated as sodium hypochlorite). This method has high energy consumption and also produces a large amount of ammonia nitrogen by-products. The ketazine process is a modified Raschig process, proposed by Bayer Company of Germany and applied to the industrial production of hydrazine hydrate. Acetone is introduced into the reaction stage of ammonia and sodium hypochlorite to form a highly stable acetone azine intermediate, which is separated and hydrolyzed to obtain a hydrazine hydrate product. This method has a high hydrazine hydrate yield (90%, calculated as sodium hypochlorite), but a large amount of ammonia needs to be recycled during the production process, resulting in high energy consumption. In addition, the above three methods all require the use of strong alkali sodium hydroxide and chlorine, which not only causes corrosion of equipment, but also produces a large amount of waste brine. At present, the domestic industrial production of hydrazine hydrate mainly adopts the urea method and the ketone azine method.

[0004] The hydrogen peroxide method uses hydrogen peroxide instead of sodium hypochlorite as an oxidant, amide as a catalyst, ammonium acid as a co-catalyst, butanone and ammonia as raw materials, first synthesizing the intermediate butanone azine, and then hydrolyzing the butanone azine at high temperature to generate hydrazine hydrate. This method avoids the use of highly corrosive chlorine and sodium hydroxide, and does not produce waste brine. It is a green and environmentally friendly production process. The use of hydrogen peroxide to produce hydrazine hydrate has gradually become the industry's recognized technology with the most promising development prospects, and has been successfully applied abroad.

[0005] In patent US6562311, acetamide-ammonium acetate is used as the catalyst system, butanone and ammonia are used as raw materials, 70% hydrogen peroxide is used as the oxidant, and the reaction is carried out at 50°C for 7 hours, and the yield of butanone azine is 81.0%. Shen Jun et al. of East China University of Science and Technology (Study on the Synthesis Process of Hydrazine Hydrate Intermediate Butanone Azine [J]. Fine Chemical Intermediates, 2008, 38(3):3) investigated the process conditions such as catalyst type, reaction temperature and reaction time, and finally used formamide as the catalyst, butanone and ammonia as raw materials, 27.5% hydrogen peroxide as the oxidant, and the reaction was carried out at 60°C for 6 hours, and the yield of butanone azine was 83.5%. Gu Chunsi et al. of East China University of Science and Technology (Study on the Process of Synthesizing Butanone Azine by Hydrogen Peroxide [J]. Chemical Reagents, 2018, 40(1):5) further optimized the formamide catalytic reaction system, and the yield of butanone azine was increased to 87.0%.

[0006] In summary, in existing industrial production equipment, the yield of butanone azine in the synthesis of butanone azine is generally 80-87%, and the product yield is still a major problem restricting industrial production. Summary of the invention

[0007] During the research process, it was found that the improvement of the butanone azine synthesis reaction in the prior art mainly focused on the catalyst system, such as compounding other co-catalyst components on the basis of amide catalysts to form an improved catalyst system. After in-depth research on the reaction system, the applicant believes that for the reaction of synthesizing butanone azine using butanone as a raw material, since butanone has limited solubility in water and the solubility further decreases with increasing temperature, the butanone azine generated by the reaction is also insoluble in water. Therefore, during the entire reaction process, the reaction system is a two-phase system including an oil phase and an aqueous phase, wherein butanone and the product butanone azine are mainly in the oil phase; ammonia, catalyst amide and oxidant hydrogen peroxide are all present in the aqueous phase, and the synthesis reaction mainly occurs at the contact interface between the aqueous phase and the oil phase. However, in the existing butanone azine synthesis process, the reaction process is mainly carried out under the condition of uniform mixing to form a turbid liquid (or emulsion) by stirring or other methods. In this system, the contact area between the water phase and the oil phase is very limited, and it is very easy to have a local violent reaction after adding hydrogen peroxide. The heat released by the reaction generates high temperature, which causes butanone and ammonia in the raw materials to volatilize and lose, and hydrogen peroxide decomposes, reducing the butanone azine synthesis reaction efficiency and product yield. Based on the above understanding, the applicant proposes a new idea of ​​adjusting the reaction system and provides a synthesis method of introducing a nonionic surfactant in the synthesis process.

[0008] In order to solve the above-mentioned deficiencies in the prior art, the core purpose of the present invention is to provide a method for synthesizing butanone azine. The synthetic method can greatly increase the effective contact area between the reaction materials by introducing a non-ionic surfactant as an auxiliary agent to adjust the reaction system environment, ensure that the synthetic reaction occurs more uniformly and rapidly, and can reduce the reaction temperature of the synthetic butanone azine, reduce energy consumption, and also have the effect of improving the reaction efficiency and the yield of butanone azine.

[0009] The present invention is achieved through the following technical solutions:

[0010] The reaction equation for synthesizing butanone azine using butanone as raw material is as follows:

[0011] 2CH3COC2H5+2NH3+H2O2→CH3(C2H5)C=NN=C(C2H5)CH3+4H2O

[0012] The invention provides a method for synthesizing butanone azine, which is to introduce a nonionic surfactant into a traditional hydrogen peroxide reaction system; the specific reaction system comprises raw materials, a catalyst, an oxidant and an auxiliary agent: the raw materials comprise butanone and ammonia water, the oxidant is hydrogen peroxide, the catalyst is an amide compound, the auxiliary agent is a nonionic surfactant, and preferably, disodium EDTA can be introduced into hydrogen peroxide as a stabilizer to reduce the natural decomposition of hydrogen peroxide.

[0013] Specifically, the present invention provides a method for synthesizing butanone azine, the method comprising the following steps:

[0014] (1) mixing butanone, aqueous ammonia, a catalyst and a nonionic surfactant to form a first stream;

[0015] (2) introducing an oxidant into the first stream under reaction conditions and reacting;

[0016] (3) After the reaction in step (2) is completed, an organic solvent is added for separation and extraction. After standing and stratification, an organic phase (containing unreacted butanone and product butanone azine) is obtained as the upper layer.

[0017] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the mass concentration of ammonia water is generally 20% to 30%, preferably 25% to 28%.

[0018] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the catalyst is an amide compound, which can be specifically selected from at least one of formamide, acetamide, propionamide, and dimethylformamide, preferably formamide.

[0019] In the above-mentioned synthesis method of butanone azine, as some specific embodiments, the non-ionic surfactant is fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkylamine and polyether, etc., which can be specifically selected from one or more of the Brij series of polyoxyethylene lauryl ether (Brij-30), polyethylene glycol hexadecyl ether (Brig-56), and polyoxyethylene ether (Brij-58), preferably polyoxyethylene lauryl ether (Brij-30).

[0020] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the reaction conditions in step (2) are as follows: the reaction temperature is 20 to 50° C., preferably 30 to 40° C.; and the reaction time is 1 to 5 hours.

[0021] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the oxidant in step (2) is a hydrogen peroxide solution, preferably a hydrogen peroxide solution containing disodium EDTA; the concentration of the hydrogen peroxide solution is 27.5wt% to 30wt%; the content of disodium EDTA in the hydrogen peroxide solution containing disodium EDTA is 0.1 to 1.0 g / mol hydrogen peroxide, preferably 0.3 to 0.5 g / mol.

[0022] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the method for introducing the oxidant in step (2) is to add the oxidant slowly, specifically by dropping, and specifically the dropping can be controlled to be completed within 1 to 2 hours.

[0023] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the amount of nonionic surfactant used is 10% to 50% of the mass of butanone.

[0024] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the separation solvent in step (3) is an organic solvent, specifically one or more of cyclohexane, n-hexane, toluene, and xylene, preferably xylene.

[0025] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the molar ratio of butanone to hydrogen peroxide is 3 to 6:1.

[0026] In the above-mentioned method for synthesizing butanone azine, as some specific implementation methods, the molar ratio of ammonia water to hydrogen peroxide is 2 to 4:1.

[0027] In the above-mentioned method for synthesizing butanone azine, as some specific embodiments, the molar ratio of formamide to hydrogen peroxide is 2 to 4:1.

[0028] Compared with the prior art, the method for synthesizing butanone azine provided by the present invention has one of the following advantages or a combination of some or all of them:

[0029] 1. The present invention provides a novel method for synthesizing butanone azine in an original way. By introducing a nonionic surfactant into the reaction system, the aqueous phase composed of ammonia and formamide is wrapped by nonionic surfactant molecules in the oil phase butanone and forms nanometer-scale droplets. The solubility of butanone in water allows butanone to act as a cosurfactant in the system, making the entire water-in-oil system more stable. Different from the water-oil separation of the traditional hydrogen peroxide reaction solution, the water-in-oil reaction system in the scheme of the present invention is a clear and transparent solution as a whole on a macroscopic scale. At this time, the introduced hydrogen peroxide will evenly enter the water phase droplets to react, greatly increasing the reaction contact area and reducing the occurrence of side reactions, thereby improving the efficiency and yield of product synthesis.

[0030] 2. The method for synthesizing butanone azine provided by the present invention has high reaction efficiency and can obtain the target product at a lower reaction temperature and in a shorter reaction time. Compared with the usual reaction temperature (50-60° C.) in the prior art, the reaction temperature is reduced by 20-30° C. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 Comparison photos of the butanone-ammonia-formamide reaction system (standing) before and after the introduction of surfactant.

[0032] Figure 2 Comparison photos of the butanone-ammonia-formamide reaction system (stirring) before and after the introduction of surfactant. DETAILED DESCRIPTION

[0033] The specific embodiments of the present invention are described in detail below, but it should be pointed out that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the claims in the appendix.

[0034] All publications, patent applications, patents and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings conventionally understood by those skilled in the art. In the event of a conflict, the definitions in this specification shall prevail.

[0035] When this specification uses the prefix "well-known to those skilled in the art", "prior art" or similar terms to introduce materials, substances, methods, steps, devices or components, etc., the objects introduced by the prefix cover those commonly used in the art when this application is filed, but also include those that are not commonly used at present but will become recognized in the art as being suitable for similar purposes.

[0036] Unless explicitly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising”, etc., will be understood to include the stated elements or components but not to exclude other elements or components.

[0037]

[0043] All numerical values ​​for parameters (eg, amounts or conditions) herein are to be understood as being modified in all instances by the term "about," whether or not "about" actually appears before the numerical value.

[0038] In the context of this specification, various chemical reagents can be obtained commercially.

[0039] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this specification are based on weight and pressure is gauge pressure.

[0040] In the context of this specification, any two or more embodiments of the present invention may be arbitrarily combined, and the technical solutions thus formed belong to part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0041] In the context of this specification, the yield of butanone azine is calculated by the following formula:

[0042]

[0043] Analytical methods:

[0044] After the reaction is completed, a certain amount of xylene is added to the system to demulsify and extract butanone azine, and the system is allowed to stand for stratification. The upper oil phase is the remaining butanone, the product butanone azine and xylene, and the lower aqueous phase is the remaining ammonia and formamide. The upper oil phase is taken for chemical analysis using an Agilent 7890A gas chromatograph (KB-5 capillary column, FID detector), and the mass of butanone azine is obtained by area normalization.

[0045] Figure 1 The macroscopic state of the solution of the butanone-ammonia-formamide reaction system when it is standing. Before the introduction of surfactants, the entire system is divided into two layers of oil and water, the upper oil phase is butanone, and the lower water phase is ammonia and formamide; after a certain amount of Brij-30 is introduced, the stratification phenomenon disappears, forming an oil-in-water system, which is a transparent and uniform solution in the macroscopic view.

[0046] Figure 2 This is the macroscopic state of the solution of the butanone-ammonia-formamide reaction system during stirring. Before the introduction of surfactants, the entire system is a turbid liquid (emulsion) and the solution is opaque; after a certain amount of Brij-30 is introduced to form an oil-in-water system, the macroscopic state is still a transparent and uniform solution.

[0047] Example 1

[0048] In a reaction apparatus equipped with a magnetic stirrer, a thermometer, a condenser reflux tube and a constant pressure dropping funnel, 200 mL of butanone, 100 mL of 25 wt% ammonia water, 50 mL of formamide and 30 g of Brij-30 were added. After stirring to form a clear and transparent oil-in-water reverse microemulsion, heating to 30 ° C was started. After the temperature stabilized, 50 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel and slowly added to the reaction system. The mixture was dripped in 1 hour, and the reaction was continued for 1 hour after the dripping. After the reaction was completed, 100 mL of xylene was added to the system to demulsify and extract butanone azine, and the stratification was allowed to stand. The upper oil phase was analyzed by gas chromatography, and the yield of butanone azine was calculated to be 93.8%.

[0049] Example 2

[0050] In a reaction apparatus equipped with a magnetic stirrer, a thermometer, a condenser reflux tube and a constant pressure dropping funnel, 200 mL of butanone, 100 mL of 25 wt% ammonia water, 50 mL of formamide and 40 g of Brij-56 were added. After stirring to form a clear and transparent oil-in-water reverse microemulsion, heating to 30 ° C was started. After the temperature stabilized, 50 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel and slowly added to the reaction system. The mixture was dripped in 1 hour, and the reaction was continued for 1 hour after the dripping. After the reaction was completed, 100 mL of xylene was added to the system to demulsify and extract butanone azine, and the stratification was allowed to stand. The upper oil phase was analyzed by gas chromatography, and the yield of butanone azine was calculated to be 89.3%.

[0051] Example 3

[0052] In a reaction apparatus equipped with a magnetic stirrer, a thermometer, a condenser reflux tube and a constant pressure dropping funnel, 200 mL of butanone, 100 mL of 25 wt% ammonia water, 50 mL of formamide and 50 g of Brij-58 were added. After stirring to form a clear and transparent oil-in-water reverse microemulsion, heating to 30 ° C was started. After the temperature stabilized, 50 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel and slowly added to the reaction system. The mixture was dripped in 1 hour, and the reaction was continued for 1 hour after the dripping. After the reaction was completed, 100 mL of xylene was added to the system to demulsify and extract butanone azine, and the stratification was allowed to stand. The upper oil phase was analyzed by gas chromatography, and the yield of butanone azine was calculated to be 85.9%.

[0053] Example 4

[0054] In a reaction apparatus equipped with a magnetic stirrer, a thermometer, a condenser reflux tube and a constant pressure dropping funnel, 430 mL of butanone, 270 mL of 25 wt% ammonia water, 130 mL of formamide and 50 g of Brij-30 were added. After stirring to form a clear and transparent oil-in-water reverse microemulsion, heating to 30 ° C was started. After the temperature stabilized, 80 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel and slowly added to the reaction system. The mixture was dripped in 1 hour, and the reaction was continued for 1 hour after the dripping. After the reaction was completed, 100 mL of xylene was added to the system to demulsify and extract butanone azine, and the stratification was allowed to stand. The upper oil phase was analyzed by gas chromatography, and the yield of butanone azine was calculated to be 90.4%.

[0055] Example 5

[0056] In a reaction apparatus equipped with a magnetic stirrer, a thermometer, a condenser reflux tube and a constant pressure dropping funnel, 110 mL of butanone, 70 mL of 25 wt% ammonia water, 30 mL of formamide and 20 g of Brij-30 were added. After stirring to form a clear and transparent oil-in-water reverse microemulsion, heating to 30 ° C was started. After the temperature stabilized, 40 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel and slowly added to the reaction system. The mixture was dripped in 1 hour, and the reaction was continued for 1 hour after the dripping. After the reaction was completed, 100 mL of xylene was added to the system to demulsify and extract butanone azine, and the mixture was allowed to stand for stratification. The upper oil phase was analyzed by gas chromatography, and the yield of butanone azine was calculated to be 91.5%.

[0057] Comparative Example 1

[0058] In a reaction apparatus equipped with magnetic stirring, a thermometer, a condensing reflux tube and a constant pressure dropping funnel, 200 mL of butanone, 100 mL of 25 wt% ammonia water and 50 mL of formamide were added. Stir and begin heating to 30°C. After the temperature stabilizes, 50 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) is added to the constant pressure dropping funnel and slowly added dropwise to the reaction system. The mixture is dripped off in 1 hour, and the reaction is continued for 1 hour after the dripping. After the reaction is completed, 100 mL of xylene is added to the system to extract butanone azine, and the mixture is allowed to stand for stratification. The upper oil phase is analyzed by gas chromatography, and the yield of butanone azine is calculated to be 45.7%.

[0059] Comparative Example 2

[0060] In a reaction apparatus equipped with magnetic stirring, a thermometer, a condensing reflux tube and a constant pressure dropping funnel, 200 mL of butanone, 100 mL of 25 wt% ammonia water and 50 mL of formamide were added. Stir and begin heating to 60 ° C. After the temperature stabilizes, 50 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel and slowly added to the reaction system. The mixture was dripped off in 1 hour and the reaction was continued for 5 hours after the dripping. After the reaction was completed, 100 mL of xylene was added to the system to extract butanone azine, and the mixture was allowed to stand for stratification. The upper oil phase was analyzed by gas chromatography, and the yield of butanone azine was calculated to be 83.2%.

[0061] Comparative Example 3

[0062] In a reaction apparatus equipped with magnetic stirring, a thermometer, a condensing reflux tube and a constant pressure dropping funnel, 200 mL of butanone, 100 mL of 25 wt% ammonia water, 50 mL of formamide and 30 g of hexadecyl trimethyl ammonium bromide (CTAB, a cationic surfactant) were added. Stirring and heating to 30 ° C, after the temperature stabilized, 50 mL of 30 wt% hydrogen peroxide (containing 0.2 g of disodium EDTA) was added to the constant pressure dropping funnel, and slowly added to the reaction system, dripped in 1 hour, and continued to react for 1 hour after dripping. After the reaction was completed, 100 mL of xylene was added to the system to demulsify and extract butanone azine, and the stratification was allowed to stand, and the upper oil phase was analyzed by gas chromatography, and the butanone azine yield was calculated to be 62.1%.

[0063] The above is a detailed description of the specific implementation of the present invention, but it is only used as an example. The present invention is not limited to the above specific implementation cases. Equivalent modifications to the microemulsion reaction system involved in the present invention are also within the protection scope of the present invention.

Claims

1. A method for synthesizing butanone azine, the method comprising the following steps: (1) mixing butanone, aqueous ammonia, a catalyst and a nonionic surfactant to form a first stream; (2) introducing an oxidant into the first stream under reaction conditions and reacting; (3) After the reaction in step (2) is completed, an organic solvent is added for separation and extraction, and the organic phase is obtained as the upper layer by standing and stratifying.

2. The method for synthesizing butanone azine according to claim 1, characterized in that: The mass concentration of ammonia water is 20% to 30%, preferably 25% to 28%.

3. The method for synthesizing butanone azine according to claim 1, characterized in that: The catalyst is an amide compound, selected from at least one of formamide, acetamide, propionamide and dimethylformamide, preferably formamide.

4. The method for synthesizing butanone azine according to claim 1, characterized in that: The nonionic surfactant is at least one of fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether, polyoxyethylene alkylamine and polyether.

5. The method for synthesizing butanone azine according to claim 1, characterized in that: The nonionic surfactant is selected from one or more of polyoxyethylene lauryl ether (Brij-30), polyethylene glycol cetyl ether (Brig-56), and polyoxyethylene ether (Brij-58), preferably polyoxyethylene lauryl ether (Brij-30).

6. The method for synthesizing butanone azine according to claim 1, characterized in that: The reaction conditions in step (2) are as follows: the reaction temperature is 20 to 50° C., preferably 30 to 40° C.; and the reaction time is 1 to 5 h.

7. The method for synthesizing butanone azine according to claim 1, characterized in that: The oxidant in step (2) is a hydrogen peroxide solution, preferably a hydrogen peroxide solution containing disodium EDTA; the concentration of the hydrogen peroxide solution is 27.5% to 30%; the content of disodium EDTA in the hydrogen peroxide solution containing disodium EDTA is 0.1 to 1.0 g / mol hydrogen peroxide, preferably 0.3 to 0.5 g / mol.

8. The method for synthesizing butanone azine according to claim 1, characterized in that: The amount of nonionic surfactant used is 10% to 50% of the mass of butanone.

9. The method for synthesizing butanone azine according to claim 1, characterized in that: The separation solvent in step (3) is an organic solvent, which is one or more of cyclohexane, n-hexane, toluene and xylene, preferably xylene.

10. The method for synthesizing butanone azine according to claim 1, characterized in that: The molar ratio of butanone to hydrogen peroxide is 3 to 5:

1.

11. The method for synthesizing butanone azine according to claim 1, characterized in that: The molar ratio of ammonia water to hydrogen peroxide is 2 to 4:

1.

12. The method for synthesizing butanone azine according to claim 1, characterized in that: The molar ratio of formamide to hydrogen peroxide is 2-4:1.

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