Preparation method of amide COF and application of amide COF in methyl ethyl ketazine synthesis

Abstract

The invention discloses a preparation method of amide COF and application of the amide COF in methyl ethyl ketazine synthesis. The preparation method of the amide COF comprises the following steps: mixing a cyano COF material with H2O2, inorganic alkali, dimethyl sulfoxide (DMSO) and methanol, carrying out a reaction under a stirring condition, carrying out centrifugal separation on a reaction product, washing a precipitate with ultrapure water, and carrying out vacuum drying to obtain the amide COF material. The synthesized amide COF material has high catalytic activity and good selectivity in the synthesis of methyl ethyl ketazine, is easy to separate and can be recycled.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical synthesis, and particularly relates to a preparation method of an amide COF and an application of the amide COF in the synthesis of butanone azine. Background Art

[0002] Hydrazine hydrate, also known as hydrated ammonia, is a colorless, transparent, oily liquid that is flammable when exposed to open flames or high temperatures. It decomposes into N2, NH3, and H2 at high temperatures. Hydrazine hydrate has extremely strong reducing properties and can react violently with halogens, HNO3, KMnO4, etc. Hydrazine hydrate is widely used, mainly in agricultural chemicals, the pharmaceutical industry, and the manufacture of foaming agents. It can also be used as a deoxidizer, fuel, reducing agent, and chemical analysis reagent.

[0003] At present, the main production methods of hydrazine hydrate are Raschig process, urea process, ketazine process and hydrogen peroxide process. Most foreign countries choose the relatively advanced ketazine process and hydrogen peroxide process, while domestic enterprises, except for a few enterprises using the ketazine process, mostly use the relatively backward urea process. The Raschig process is the earliest method for industrial hydrazine production. It was used for industrial production of hydrazine in 1906. This method is suitable for large-scale production, with low raw material prices and is relatively economical, but it is highly polluting and energy-consuming. The urea process simplifies equipment investment and is easy to operate. This method is suitable for small-scale production, but in large-scale production, the disadvantages of high raw material prices and high energy consumption of the urea process become very obvious, and it cannot compete with other methods. Therefore, it has been gradually eliminated abroad, but it is still the main process for producing hydrazine hydrate in my country. The ketazine process evolved from the Raschig process. By adding acetone, it forms a relatively stable acetone azine with active hydrazine. Since the generated intermediate product acetone azine will not be further oxidized, the problem of easy decomposition and loss of hydrazine in the Raschig process and the urea process is solved, and the product yield is improved. With the promotion of the ketazine process, its disadvantages are gradually highlighted, and there are a large amount of salt-containing wastewater and organic by-products to be treated. The hydrogen peroxide process is an improvement on the ketazine process. It is a new process successfully developed by the French PCUK company and has developed rapidly in the mid-1970s. This method uses hydrogen peroxide to replace Cl2 or NaClO as a new oxidant to react with ammonia in the presence of butanone and amide. The advantages of the hydrogen peroxide method are: no salt by-products, less environmental pollution, and less ammonia; using hydrogen peroxide as an oxidant avoids the use of chlorine, reduces pollution and improves conversion rate.

[0004] At present, in the method of synthesizing butanone azine using hydrogen peroxide, the catalyst used is generally a homogeneous catalyst such as ammonium formate, ammonium acetate, formamide, acetamide, etc., which has problems in catalyst recycling and post-treatment. Therefore, it is of great significance in the field of hydrazine hydrate to explore and develop new and efficient heterogeneous catalysts for synthesizing butanone azine. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides a method for preparing an amide COF and its application in the synthesis of butanone azine. The amide COF material synthesized by the present invention has high catalytic activity and good selectivity in the synthesis of butanone azine, and is easy to separate and can be recycled. The amide COF is an amide covalent organic framework material (Covalent Organic Frameworks) The preparation method of amide COF of the present invention comprises the following contents: mixing cyano COF material with H2O2, inorganic base, dimethyl sulfoxide (DMSO) and methanol, reacting under stirring conditions, centrifuging the reaction product, washing and drying the precipitate to obtain the amide COF material.

[0006] In the method of the present invention, the cyano COF 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 COF 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.

[0007] Furthermore, taking 2DPPV-COF as an example, its preparation method is: add terephthalonitrile and 1,3,5-tri(4-formylphenyl)benzene monomers into a glass tube, add alkali catalyst Cs2CO3 and o-dichlorobenzene, and ultrasonically treat to obtain a reaction mixture; place the reaction container containing the reaction mixture in liquid nitrogen for freezing, replace the upper air of the solution with nitrogen and seal the reaction container, react at 120-180°C for 2-5 days, take out and cool to room temperature; after centrifuging the reaction product, wash it with tetrahydrofuran and ethanol until the filtrate is clear, and dry it to obtain a cyano-2DPPV-COF material; the molar ratio of terephthalonitrile, 1,3,5-tri(4-formylphenyl)benzene, alkali catalyst Cs2CO3 and o-dichlorobenzene is 3:2:(5~15):(200~300).

[0008] In the method of the present invention, the molar ratio of H2O2, cyano COFs, inorganic base, DMSO and methanol is 1:0.01~0.2:2~4:0.5~1:8~15.

[0009] In the method of the present invention, the inorganic base is one or more of KOH, NaOH, K2CO3, K3PO4, Na2CO3, Cs2CO3 and CsOH, preferably K2CO3.

[0010] In the method of the present invention, the mass concentration of H2O2 is 25wt%~70wt%, preferably 30wt% H2O2.

[0011] In the method of the present invention, the reaction temperature is 20-40° C. and the reaction time is 0.5-5 hours.

[0012] In the method of the present invention, the washing is generally carried out with ultrapure water until the filtrate is colorless; the drying conditions are: the drying temperature is 60-100°C, and the drying time is 4-10 hours. The amide COF prepared by the method of the present invention is used in the catalytic synthesis of butanone azine. The amide COF is used as a solid catalyst, butanone and ammonia water are used as raw materials, and H2O2 is used as an oxidant to synthesize butanone azine at a certain reaction temperature.

[0013] Furthermore, the amide COF is one or more of amide-2DPPV-COF, amide-sp2c-COF and amide-JUC-505-COF.

[0014] Furthermore, the molar ratio of the amide COF to H2O2, butanone and ammonia is 0.01-0.025:1:3-5.5:2-5.

[0015] Furthermore, the reaction temperature is 35-60° C., and the reaction time is 2-8 hours.

[0016] Furthermore, the mass concentration of aqueous ammonia is 20wt% to 60wt%, preferably 25wt% aqueous ammonia; the mass concentration of hydrogen peroxide is 25wt% to 70wt%, preferably 30wt% hydrogen peroxide.

[0017] Compared with the prior art, the present invention has the following beneficial effects: (1) The present invention prepares amide covalent organic framework materials by in-situ hydrolysis of amides on cyano-functionalized covalent organic frameworks. The method is simple and the materials are stable. The structural advantage of the regular pores of the covalent organic framework enables the reactant molecules and product molecules in the system to have better flow capacity, and the catalysis is more efficient.

[0018] (2) The amide covalent organic framework material of the present invention has the advantages of high catalytic activity and high selectivity compared with traditional homogeneous catalysts, and the catalyst is easy to separate, recover and recycle. It can be used as a high-efficiency catalyst for the synthesis of butanone azine, an important intermediate product of hydrazine hydrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1This is the gas chromatogram of the synthesis of butanone azine using amide-2DPPV-COF as the catalyst in Example 5. DETAILED DESCRIPTION

[0020] 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

[0021] 30 mg of terephthalonitrile and 50 mg of 1,3,5-tri(4-formylphenyl)benzene monomer were added to a glass tube, and 60 mg of CS2CO3 and 2 mL of o-dichlorobenzene were added as a base catalyst, and a reaction mixture was obtained by ultrasonic treatment; the glass tube containing the reaction mixture was placed in liquid nitrogen for freezing, and the reaction container was sealed after replacing the upper air of the solution with nitrogen, and reacted at 150°C for 3 days, and then taken out and cooled to room temperature; the reaction product was centrifuged, and the precipitate was washed with tetrahydrofuran and ethanol and then vacuum dried to obtain cyano-2DPPV-COF material. 0.5 g of cyano-2DPPV-COF material was weighed, 2 g of 30% H2O2, 5 g of K2CO3, 1.5 mL of DMSO and 10 mL of methanol were added, stirred, and reacted at 30°C for 2 hours; the reaction product was centrifuged, and the precipitate was washed with ultrapure water and then vacuum dried to obtain amide-2DPPV-COF material. Example 2

[0022] 30 mg of terephthalonitrile and 50 mg of 1,3,5-tri(4-formylphenyl)benzene monomer were added to a glass tube, 150 mg of Cs2CO3 and 3 mL of o-dichlorobenzene were added as a base catalyst, and a reaction mixture was obtained by ultrasonic treatment; 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, and the reaction was carried out at 120°C for 5 days, and the reaction was taken out and cooled to room temperature; the reaction product was centrifuged, the precipitate was washed with tetrahydrofuran and ethanol, and then vacuum dried to obtain cyano-2DPPV-COF material. 0.3 g of cyano-2DPPV-COF material was weighed, 2 g of 30% H2O2, 5 g of K2CO3, 1.3 mL of DMSO and 10 mL of methanol were added, stirred, and reacted at 30°C for 5 hours; the reaction product was centrifuged, the precipitate was washed with ultrapure water, and then vacuum dried to obtain amide-2DPPV-COF material. Example 3

[0023] 32.4 mg of 2,3,6,7,10,11-hexahydroxytriphenylene, 30 mg of tetrafluoroterephthalonitrile and 138.2 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 air above 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. Weigh 0.3 g of cyano-JUC-505-COF, add 1 g of 50% H2O2, 6.5 g of K2CO3, 1.5 mL of DMSO and 8 mL of methanol, stir, and react at 25°C for 5 hours; the reaction product is centrifuged, the precipitate is washed with ultrapure water and then vacuum dried to obtain amide-JUC-505-COF material. Example 4

[0024] Add 40 g of butanone, 30 g of 25% ammonia water, and 0.5 g of amide-JUC-505-COF to a three-necked flask, stir and start heating to 40°C. After the temperature stabilizes, slowly drop 9 g of 50% hydrogen peroxide into the flask at a uniform rate and continue the reaction for 5 hours. After the reaction is completed, filter out the catalyst, add 30 mL of xylene to the system, extract, let stand and separate, take the upper oil phase and analyze it by gas chromatography. The yield of butanone azine is calculated to be 88.2%. Centrifuge and filter the catalyst, and use methanol and other solvents for post-treatment and continue to use it. The effect does not change after three cycles. Example 5

[0025] Add 40 g of butanone, 20 g of 25% ammonia water, and 0.8 g of amide-2DPPV-COF to a three-necked flask, stir and start heating to 50°C. After the temperature stabilizes, slowly add 14 g of 30% hydrogen peroxide to the flask at a uniform rate and continue the reaction for 2 hours. After the reaction is completed, filter out the catalyst, add 30 mL of xylene to the system, extract, let stand and separate, and take the upper oil phase for analysis by gas chromatography. Figure 1 As shown, the calculated yield of butanone azine is 93.5%. Example 6

[0026] Add 40 g of butanone, 15 g of 50% ammonia water, and 0.8 g of amide-sp2c-COF to a three-necked flask, stir and start heating to 50°C. After the temperature stabilizes, slowly drop 14 g of 30% hydrogen peroxide into the flask at a uniform rate and continue the reaction for 2 hours. After the reaction is completed, filter out the catalyst, add 30 mL of xylene to the system, extract, stand and separate, take the upper oil phase and analyze it by gas chromatography. The yield of butanone azine is calculated to be 90.2%.

[0027] Comparative Example 1 Add 0.5 g of cyano-2DPPV-COF material to a three-necked flask, then add 14 g of 30% hydrogen peroxide, stir at room temperature for 3 hours, add 40 g of butanone and 20 g of 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 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 11.7%.

Claims

1. A method for preparing an amide COF, characterized in that The method comprises the following contents: a cyano COF material is mixed with H2O2, an inorganic base, dimethyl sulfoxide and methanol, reacted under stirring conditions, the reaction product is centrifuged, and the precipitate is washed and dried to obtain an amide COF material.

2. The method according to claim 1, characterized in that: The cyano COF 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 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 an alkali catalyst Cs2CO3 and o-dichlorobenzene, and performing ultrasonic treatment to obtain a reaction mixture; placing a reaction container containing the reaction mixture in liquid nitrogen for freezing, 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 then vacuum drying to obtain a cyano-2DPPV-COF material; the molar ratio of terephthalonitrile, 1,3,5-tri(4-formylphenyl)benzene, the alkali catalyst Cs2CO3 and o-dichlorobenzene is 3:2:5~15:200~300.

4. The method according to claim 1, characterized in that: The molar ratio of H2O2, cyano COFs, inorganic base, dimethyl sulfoxide and methanol is 1:0.01-0.2:2-4:0.5-1:8-15.

5. The method according to claim 1, characterized in that: The inorganic base is one or more of KOH, NaOH, K2CO3, K3PO4, Na2CO3, Cs2CO3 and CsOH.

6. The method according to claim 1, characterized in that: The reaction temperature is 20-40°C, and the reaction time is 0.5-5 hours.

7. Use of the amide COFs prepared according to any one of claims 1 to 6 in the catalytic synthesis of butanone azine.

8. The use according to claim 7, characterized in that: Using amide COFs as solid catalyst, butanone and ammonia as raw materials, H2O2 as oxidant, butanone azine was synthesized at a certain reaction temperature.

9. The use according to claim 7, characterized in that: The amide COFs are one or more of amide-2DPPV-COF, amide-sp2c-COF and amide-JUC-505-COF.

10. The use according to claim 7, characterized in that: The molar ratio of the amide COFs to H2O2, butanone and ammonia is 0.01-0.025:1:3-5.5:2-5.

11. The use according to claim 7, characterized in that: The reaction temperature is 35-60°C and the reaction time is 2-8 hours.

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