Synthetic method of methyl ethyl ketazine

Abstract

The invention discloses a synthetic method of methyl ethyl ketazine, which comprises the following steps: taking a cyano covalent organic framework material as a solid catalyst, taking butanone and ammonia water as raw materials, taking a hydrogen peroxide solution as an oxidizing agent, adding a certain amount of dimethyl sulfoxide (DMSO) and inorganic base, and reacting at a certain temperature to synthesize the methyl ethyl ketazine. According to the method, the catalyst is easy to separate, recover and recycle, and the yield of methyl ethyl ketazine is high.

Description

Technical Field

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

[0002] Ketazine is an important intermediate for the preparation of hydrazine hydrate. Hydrazine hydrate can be obtained by hydrolyzing ketazine under certain conditions. Hydrazine hydrate is a colorless oily liquid with an ammonia smell. It is widely used in the field of pesticide synthesis, the pharmaceutical industry and the military industry. It is an important chemical raw material and an important chemical product.

[0003] The industrial methods for producing hydrazine hydrate can be roughly divided into four types, namely the Raschig process, the urea process, the ketazine process and the hydrogen peroxide process. Among them, the Raschig process uses sodium hypochlorite as an oxidant to oxidize ammonia to obtain a low-concentration hydrazine hydrate solution. This method has a low product yield and 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 produce hydrazine hydrate. 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 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, but a large amount of ammonia needs to be recycled during the production process, resulting in high energy consumption. The hydrogen peroxide method uses hydrogen peroxide instead of sodium hypochlorite to generate stable butanone azine with an ammonia source and butanone, which is then hydrolyzed to produce hydrazine hydrate. This method has little pollution to the environment and a high conversion rate. It has application examples abroad. In China, the industrial production of hydrazine hydrate mainly uses the urea method and the ketone azine method.

[0004] In summary, the Raschig method, urea method, and ketone azine method all require the use of strong bases such as sodium hydroxide and chlorine, which not only cause corrosion of the equipment, but also produce a large amount of waste brine as a by-product. Therefore, the environmentally friendly hydrogen peroxide method has attracted the attention of more and more researchers in the synthesis of hydrazine hydrate intermediate butanone azine. At present, some researchers use homogeneous catalysts such as formamide and acetamide to catalyze the reaction. This is based on the fact that amides can be converted into more active peroxyimidic acid in a hydrogen peroxide system, thereby catalyzing the reaction. The use of such homogeneous catalysts faces the problem of catalyst separation and recycling. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for synthesizing butanone azine, which uses cyano covalent organic framework materials (Covalent Organic Frameworks, COFs) to react with hydrogen peroxide and inorganic bases in the system to generate intermediate active substances to catalyze the reaction. This synthesis method is relatively simple and has good reaction effect.

[0006] The method for synthesizing butanone azine of the present invention comprises the following contents: using a cyano covalent organic framework material as a solid catalyst, using butanone and ammonia water as raw materials, using a hydrogen peroxide solution as an oxidant, adding a certain amount of dimethyl sulfoxide (DMSO) and an inorganic base, and reacting and synthesizing butanone azine at a certain temperature.

[0007] In the method of the present invention, the cyano covalent organic framework material is selected from one or more of 2DPPV-COF, sp2c-COF connected by carbon-carbon double bonds, and JUC-505 connected by polyether bonds. The cyano covalent organic framework material can be prepared according to the prior art, such as 2DPPV-COF prepared by the method of Journal Name, 2013, 00, 1 (DOI: 10.1039 / C6PY00561F), sp2c-COF prepared by the method of Nature Communications, 2018, 9, 4143 (DOI: 10.1038 / s41467-018-06719-8), and JUC-505 prepared by the method of CN 108855012 A.

[0008] Taking 2DPPV-COF as an example, its preparation method is: Add terephthalonitrile and 1,3,5-tri(4-formylphenyl)benzene monomers to the glass tube, and add the base catalyst Cs 2 CO 3 and o-dichlorobenzene, and ultrasonically treat to obtain a reaction mixture; freeze a reaction container containing the reaction mixture in liquid nitrogen, replace the air above the solution with nitrogen, seal the reaction container, react at 120-180° C. for 2-5 days, take out and cool to room temperature; centrifuge the reaction product, wash the precipitate with tetrahydrofuran and ethanol, and then vacuum dry to obtain a cyano-2DPPV-COF material.

[0009] In the method of the present invention, the inorganic base is KOH, K 2 CO 3 、Na 2 CO 3 , Cs 2 CO 3 One or more of, preferably K 2 CO 3 .

[0010] In the method of the present invention, the molar ratio of the cyano covalent organic framework material, hydrogen peroxide solution, butanone, ammonia, DMSO and inorganic base is: 0.005-0.02: 1: 2-4: 1-4: 0.1-1: 0.5-2, wherein the hydrogen peroxide solution is H 2 O 2 count.

[0011] In the method of the present invention, the concentration of the hydrogen peroxide solution used is 25wt%~70wt%, preferably 30wt%~50wt%; the concentration of the ammonia solution is 25wt%~50wt%, preferably 25wt%~30wt%.

[0012] In the method of the present invention, the reaction temperature is 35-60° C. and the reaction time is 2-10 hours.

[0013] In the method of the present invention, after the reaction is completed, the solid catalyst is filtered out, and then the reaction is allowed to stand for stratification, and the upper organic phase is distilled at normal pressure to obtain the product butanone azine.

[0014] Compared with the prior art, the invention has the following beneficial effects: the invention uses a cyano-functionalized covalent organic framework material as a catalyst, and can obtain butanone azine in a one-pot process with butanone and ammonia without undergoing a post-modification step, and its mechanism is that in a system in which hydrogen peroxide exists, a cyano group can be in situ hydrolyzed into an amide, thereby having catalytic activity; the cyano-functionalized covalent organic framework material of the invention is easy to separate, recycle and recycle compared with a traditional homogeneous catalyst, and the structural advantage of the regular pores of the covalent organic framework enables the reactant molecules and the product molecules in the system to have better flow capacity, and the catalysis is more efficient, and therefore, the invention can be used as a high-efficiency catalyst for synthesizing butanone azine, an important intermediate product of hydrazine hydrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The gas chromatogram of the synthesis of butanone azine using cyano-2DPPV-COF as the catalyst. DETAILED DESCRIPTION

[0016] The present invention is not limited to the following specific embodiments. A person skilled in the art can implement the present invention in various other specific embodiments according to the contents disclosed in the present invention, or any simple changes or modifications made to the design structure and ideas of the present invention fall within the protection scope of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict. Example 1

[0017] Add 30 mg of terephthalonitrile and 50 mg of 1,3,5-tri(4-formylphenyl)benzene monomer to a glass tube, and add 60 mg of cesium as a base catalyst. 2 CO 3 and 2 mL of o-dichlorobenzene, and ultrasonically treated to obtain a reaction mixture; freezing the glass tube containing the reaction mixture in liquid nitrogen, replacing the upper air of the solution with nitrogen, and sealing the reaction container, reacting at 150° C. for 3 days, and cooling to room temperature; centrifuging the reaction product, washing the precipitate with tetrahydrofuran and ethanol, and then vacuum drying to obtain a cyano-2DPPV-COF material. Example 2

[0018] 32.4 mg of 2,3,6,7,10,11-hexahydroxytriphenylene, 30 mg of tetrafluoroterephthalonitrile and 138 mg of anhydrous potassium carbonate were added to a glass tube, mixed well, 0.3 mL of mesitylene and 0.6 mL of 1-methylpyrrolidone were added, and ultrasonic treatment was performed to obtain a reaction mixture; the glass tube containing the reaction mixture was placed in liquid nitrogen for freezing, the upper air of the solution was replaced with nitrogen, the reaction container was sealed, the reaction was carried out at 120° C. for 3 days, and the reaction was taken out and cooled to room temperature; the reaction product was centrifuged, the precipitate was washed with tetrahydrofuran and acetone, and then vacuum dried to obtain cyano-JUC-505-COF. Example 3

[0019] In a three-necked flask, 0.5 g of cyano-2DPPV-COF material and 1 g of K 2 CO 3 and 0.5 mL DMSO, then add 14 g 30% hydrogen peroxide, stir at room temperature for 2 h, add 40 g butanone and 30 g 25% ammonia water, heat to 40 ° C, and continue to react for 5 hours. After the reaction is completed, filter out the catalyst, add 30 mL xylene to the system, extract, stand and separate, take the upper oil phase and analyze it by gas chromatography, and the yield of butanone azine is calculated to be 85.9 wt%. Example 4

[0020] In a three-necked flask, add 0.8 g of cyano-sp2c-COF material, 1.2 g of K 2 CO 3 and 0.5 mL DMSO, then add 14 g 30% hydrogen peroxide, stir at room temperature for 3 h, add 40 g butanone and 20 g 25% ammonia water, raise the temperature to 50 ° C, and continue to react for 5 hours. After the reaction is completed, filter out the catalyst, add 30 mL xylene to the system, extract, stand and separate, take the upper oil phase and analyze it by gas chromatography, such as Figure 1 As shown, the calculated yield of butanone azine is 89.0wt%. Example 5

[0021] In a three-necked flask, add 0.5 g of cyano-JUC-505 material, 1 g of K 2 CO 3 and 0.5 mL DMSO, then add 9 g 50% hydrogen peroxide, stir at room temperature for 3 h, add 40 g butanone and 20 g 25% ammonia water, heat to 50 ° C, and continue to react for 5 hours. After the reaction is completed, filter out the catalyst, add 30 mL xylene to the system, extract, stand and separate, take the upper oil phase and analyze it by gas chromatography, and the yield of butanone azine is calculated to be 86.2 wt%.

[0022] Comparative Example 1 Add 0.8g of cyano-2DPPV-COF material to a three-necked flask, then add 14g of 30% hydrogen peroxide, stir at room temperature for 3h, add 40g of butanone and 20g of 25% ammonia water, heat to 50℃, and continue to react for 5h. After the reaction, filter out the catalyst, add 30mL of xylene to the system, extract, stand and separate, take the upper oil phase and analyze it by gas chromatography, and the yield of butanone azine is calculated to be 14.1wt%.

Claims

1. A method for synthesizing butanone azine, characterized in that The method includes the following contents: using cyano covalent organic framework material as solid catalyst, butanone and ammonia water as raw materials, hydrogen peroxide solution as oxidant, adding a certain amount of dimethyl sulfoxide (DMSO) and inorganic base, and reacting at a certain temperature to synthesize butanone azine.

2. The synthesis method according to claim 1, characterized in that: The cyano covalent organic framework material is selected from one or more of 2DPPV-COF and sp2c-COF connected by carbon-carbon double bonds, and JUC-505 connected by polyether bonds.

3. The synthesis method according to claim 2, characterized in that: The preparation method of 2DPPV-COF is as follows: adding terephthalonitrile and 1,3,5-tri(4-formylphenyl)benzene monomers into a glass tube, adding a base catalyst Cs2CO3 and o-dichlorobenzene, and performing ultrasonic treatment to obtain a reaction mixture; freezing a reaction container containing the reaction mixture in liquid nitrogen, replacing the upper air of the solution with nitrogen, sealing the reaction container, reacting at 120-180°C for 2-5 days, taking out and cooling to room temperature; centrifuging the reaction product, washing the precipitate with tetrahydrofuran and ethanol, and drying to obtain a cyano-2DPPV-COF material.

4. The synthesis method according to claim 1, characterized in that: The inorganic base is one or more of KOH, K2CO3, Na2CO3, Cs2CO3, preferably K2CO3.

5. The synthesis method according to claim 1, characterized in that: The molar ratio of the cyano covalent organic framework material, hydrogen peroxide solution, butanone, ammonia, DMSO and inorganic base is: 0.005-0.02: 1: 2-4: 1-4: 0.1-1: 0.5-2, wherein the hydrogen peroxide solution is calculated as H2O2.

6. The synthesis method according to claim 1, characterized in that: The concentration of the hydrogen peroxide solution is 25wt%~70wt%, preferably 30wt%~50wt%.

7. The synthesis method according to claim 1, characterized in that: The concentration of the aqueous ammonia solution is 25wt% to 50wt%, preferably 25wt% to 30wt%.

8. The synthesis method according to claim 1, characterized in that: The reaction temperature is 35-60°C, and the reaction time is 2-10 hours.

9. The synthesis method according to claim 1, characterized in that: After the reaction is completed, the solid catalyst is filtered out, and then the mixture is allowed to stand for stratification. The upper organic phase is distilled to obtain the product butanone azine.

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