A high-nitrogen-content porous carbon-nitrogen compound material and a preparation method thereof

Abstract

The application discloses a high-nitrogen-content porous carbon-nitrogen compound material and a preparation method thereof. In the preparation method of the high-nitrogen-content porous carbon-nitrogen compound material, first, cyanuric acid is synthesized by hydrazinolysis of cyanuric acid ester, and then, the high-nitrogen-content porous carbon-nitrogen compound is prepared by taking cyanuric chloride as a chlorine source, taking tetrahydrofuran as a reaction solvent, taking N,N-diisopropyl ethylamine as an acid-binding agent and a catalyst, and adopting a condensation reflux mode.

Description

Technical Field

[0001] This invention relates to the field of chemistry, specifically to a porous carbon-nitrogen compound material with high nitrogen content and its preparation method. Background Technology

[0002] With the rapid development of modern electronic information technology, problems such as electromagnetic interference and communication security have become increasingly prominent, leading to growing attention on microwave absorbing materials. Furthermore, microwave absorbing materials also have significant applications in the military field. Therefore, developing high-performance microwave absorbing materials to meet civilian needs is of great importance to both economic development and national defense security.

[0003] Developing novel "thin, strong, light, and wide" absorbing materials with thin thickness, strong absorption capacity, light weight, and wide absorption bandwidth is currently key to the field of electromagnetic wave absorption. Commonly used absorbing materials include inorganic nanomaterials, ferrites, and conductive polymers. Among these, carbonitrides (CNs) have significant application potential in energy storage and conversion due to their high nitrogen content and porous structure. In particular, pyridine nitrogen-rich CNs possess high structural stability, good conductivity, and a strong affinity for metal ions. Therefore, by leveraging the strong affinity between CNs and metal ions, they can be combined with compounds containing magnetic metal ions to prepare absorbing materials that simultaneously exhibit magnetic and dielectric losses. However, to achieve the above strategy, two problems must be solved: (1) Currently synthesized carbonitrides are mainly synthesized through high-temperature solid-state reactions, resulting in a small specific surface area and difficulty in binding a large number of magnetic metal ions, leading to the need for more material to achieve the desired effect; (2) During the preparation process, high-valence metal ions need to be converted into low-valence oxygen compounds through high-temperature carbon reduction reactions, which may damage the material structure and thus affect the material's microwave absorption effect. Obviously, if a carbonitride compound with high specific surface area and reducing properties can be synthesized, the above two problems can be perfectly solved. Obviously, for the first problem, the reaction rate can be increased by dispersing or dissolving the reactants in the reaction solvent, thus synthesizing carbonitride compounds with a large specific surface area. In addition, in order to reduce the preparation temperature, reducing functional groups can be introduced during the material design process.

[0004] In view of this, it is indeed necessary to provide a new carbon-nitrogen compound to solve the above problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing carbon and nitrogen compounds with reducing properties, high nitrogen content, and high specific surface area.

[0006] To achieve the above objectives, this invention discloses: 1. A method for preparing a porous carbon-nitrogen compound with high nitrogen content, comprising the following steps:

[0007] Step 1: Preparation and acquisition of melamine;

[0008] Step 2 involves mixing melamine, cyanuric chloride, N,N-diisopropylethylamine, and the reaction medium in a specific ratio and heating the mixture to prepare the product.

[0009] Step 3: Wash the product with an organic solvent and dry it under vacuum to prepare the high-nitrogen-content porous carbon-nitrogen compound.

[0010] Further, step 1 specifically involves: dissolving cyanurate in anhydrous ethanol by stirring at room temperature; then adding hydrazine hydrate dropwise to the mixture using a constant pressure titration funnel; heating the mixture to 60-120°C and stirring until the reaction is complete; cooling to room temperature; separating the solid product by vacuum filtration; and washing the solid product multiple times with deionized water and dioxane to obtain the cyanuric acid hydrazine.

[0011] Further, step 2 specifically involves: first, adding a mixture of cyanuric chloride, melamine, and tetrahydrofuran into a three-necked flask; then, adding a mixture of N,N-diisopropylethylamine and tetrahydrofuran under stirring conditions; and slowly heating to specific temperatures, namely 60, 80, 100, and 120°C, to allow for sufficient reaction and preparation of the product.

[0012] Furthermore, step 3 specifically involves washing the product prepared in step 2 with an organic solvent, purifying the product, and vacuum drying to obtain a porous carbon-nitrogen compound material with high nitrogen content.

[0013] A high-nitrogen-content porous carbon-nitrogen compound material, wherein the polymer is an organic polymer composed of hydrazine-bridged triazine rings with a porous structure, and the high-nitrogen-content porous carbon-nitrogen compound is prepared by the above-described method for preparing high-nitrogen-content porous carbon-nitrogen compound materials.

[0014] The beneficial effects of this invention are as follows: The method for preparing high-nitrogen-content porous carbon-nitrogen compounds utilizes the hydrazinolysis of cyanurate to prepare cyanuric acid hydrazine, with tetrahydrofuran as the reaction medium and cyanuric chloride as the organic active small molecule. The resulting carbon-nitrogen compounds exhibit high specific surface area, high nitrogen content, and strong reducing properties, demonstrating significant application potential. Attached Figure Description

[0015] Figure 1 This is a flowchart illustrating the preparation of porous carbon and nitrogen compounds with high nitrogen content in this invention.

[0016] Figure 2 FT-IR spectrum of the product

[0017] Figure 3 N2 adsorption-desorption curves of materials synthesized at 60℃

[0018] Figure 4 N2 adsorption-desorption curves of materials synthesized at 80℃

[0019] Figure 5 N2 adsorption-desorption curves of materials synthesized at 100℃

[0020] Figure 6 N2 adsorption-desorption curves of materials synthesized at 120℃

[0021] Figure 7 SEM images of materials synthesized at 100℃ Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0023] It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and / or processing steps closely related to the present invention are shown in the accompanying drawings, while other details that are not closely related to the present invention are omitted.

[0024] Additionally, it should be noted that the terms “comprising,” “including,” or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0025] Please refer to Figure 1 The method for preparing high-nitrogen-content porous carbon-nitrogen compounds provided by the present invention includes the following steps:

[0026] Step 1: Preparation and acquisition of melamine;

[0027] St2, melamine, cyanuric chloride, N,N-diisopropylethylamine and the reaction medium are mixed in proportion and heated to prepare a product / salt mixture;

[0028] Step 3: Wash and dry the product to prepare a porous carbon-nitrogen compound material with high nitrogen content.

[0029] The following instruction manual will describe S1 to S3 in detail.

[0030] St1 specifically refers to:

[0031] A mixture was prepared by adding 8 g (46.6 mmol) of cyanurate to 600 mL of anhydrous ethanol. Then, 74 mL of hydrazine hydrate was added dropwise to the mixture. The mixture was heated to 60-120 °C and reacted for 24 h. After cooling to room temperature, the solid product was separated by vacuum filtration. The solid product was washed three times with dichloromethane, dioxane, ethanol, and deionized water to obtain cyanuric acid hydrazine. The specific reaction equation is as follows:

[0032]

[0033] It is evident that the melamine prepared using S1 in this invention is rich in a large number of hydrazine functional groups.

[0034] As can be seen from the table, the optimal reaction temperature for preparing melamine is 120℃.

[0035] Preparation conditions C(wt%) N (wt%) H (wt%) S(wt%) 60℃,24h 26.26 52.37 2.83 1.79 80℃,24h 22.07 60.03 5.06 0.46 100℃,24h 22.61 69.22 5.12 0 120℃,24h 21.21 72.86 5.23 0 Theoretical products 21.05 73.65 5.30 0

[0036] St2 specifically refers to:

[0037] A mixture of 1 g cyanuric chloride, 0.924 g melamine, and 40 mL tetrahydrofuran was added to a 250 mL three-necked flask. Then, a mixture of 5.65 mL N,N-diisopropylethylamine and 40 mL tetrahydrofuran was added under stirring. The mixture was slowly heated to specific temperatures (60, 80, 100, and 120 °C) and reacted for 24 h.

[0038] St3 specifically refers to

[0039] The product was obtained by vacuum drying with acetone, N,N-dimethylformamide, dimethyl sulfoxide, tetrahydrofuran, water, and anhydrous ethanol as washing agents at 80°C. Specific surface area characterization results showed that the optimal reaction temperature was 100°C.

[0040]

[0041] Figure 2 The FT-IR spectra of the products show that all four products contain triazine rings and hydrazine functional groups, confirming the synthesis of the materials.

[0042] Figure 3 , Figure 4 , Figure 5 and Figure 6 The N2 adsorption-desorption curves are shown for the products synthesized at four different temperatures. It can be seen that the specific surface areas of the products synthesized at 60, 80, 100, and 120℃ are 106.7, 146, 207, and 191 m², respectively. 2 g -1A larger specific surface area indicates larger pores in the material, which is more conducive to multiple reflections of electromagnetic waves and allows for the integration of more functional nanomaterials. In summary, the optimal synthesis temperature for this material is 100℃. Based on the specific surface area characterization results, the optimal reaction temperature for synthesizing high-nitrogen-content porous carbonitride compounds is also 100℃.

[0043] Figure 7 The image shows a SEM image of the material synthesized at 100℃; the image shows that the material has a structure with abundant pores.

[0044] In summary, the method for preparing high-nitrogen-content porous carbon-nitrogen compounds of this invention utilizes cyanurate hydrazine hydrolysis to synthesize cyanuric acid hydrazine, and uses tetrahydrofuran as the reaction medium and cyanuric chloride as the organic active small molecule. The resulting carbon-nitrogen compounds have high specific surface area, high nitrogen content, and strong reducing properties, and have great application potential.

[0045] The above embodiments are only used to illustrate the present invention and are not intended to limit the technical solutions described in the present invention. The understanding of this specification should be based on those skilled in the art. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still make modifications or equivalent substitutions to the present invention. All technical solutions and improvements that do not depart from the spirit and scope of the present invention should be covered within the scope of the claims of the present invention.

Claims

1. A method for preparing a porous carbon-nitrogen compound with high nitrogen content, characterized in that, Includes the following steps: Step 1: Preparation and acquisition of melamine; Step 2: Melamine, cyanuric chloride, N,N-diisopropylethylamine and the reaction medium are mixed in proportion and heated to prepare the product; Step 3: Wash and dry the product to prepare the high-nitrogen-content porous carbon-nitrogen compound.

2. The method for preparing a high-nitrogen-content porous carbon-nitrogen compound according to claim 1, characterized in that, The specific steps for preparing melamine in step 1 are as follows: Melamine ester was dissolved in anhydrous ethanol by stirring at room temperature. Then, hydrazine hydrate was added dropwise to the mixture formed by stirring and dissolving melamine ester in anhydrous ethanol. The mixture was heated to 60-120 °C and stirred until the reaction was complete. After cooling to room temperature, the solid product was separated by vacuum filtration and washed multiple times to obtain the melamine hydrazine.

3. The method for preparing a high-nitrogen-content porous carbon-nitrogen compound according to claim 2, characterized in that... The solid product was washed multiple times with deionized water and dioxane.

4. The method for preparing high-nitrogen-content porous carbon-nitrogen compounds according to claim 1, characterized in that, Step 2, which involves mixing melamine, cyanuric chloride, N,N-diisopropylethylamine, and the reaction medium in a specific ratio and heating to prepare the product, specifically involves: First, a mixture of cyanuric chloride, melamine, and tetrahydrofuran is added to a three-necked flask. Then, a mixture of N,N-diisopropylethylamine and tetrahydrofuran is added under stirring. The mixture is slowly heated to a specific temperature to allow for a complete reaction and prepare the product.

5. The method for preparing high-nitrogen-content porous carbon-nitrogen compounds according to claim 4, characterized in that... The specific temperatures are 60, 80, 100, and 120 °C, respectively.

6. The method for preparing high-nitrogen-content porous carbon-nitrogen compounds according to claim 1, characterized in that... The product described in step 3 was washed with an organic solvent and then vacuum dried to obtain the final product.

7. A porous carbonitride material with high nitrogen content, characterized in that: A mixture of cyanuric chloride, melamine, and tetrahydrofuran is added to a three-necked flask. Then, under stirring, a mixture of N,N-diisopropylethylamine and tetrahydrofuran is added and reacted thoroughly to prepare a polymer that is an organic polymer composed of hydrazine-bridged triazine rings with a porous structure. The high-nitrogen-content porous carbon-nitrogen compound is prepared by the method for preparing high-nitrogen-content porous carbon-nitrogen compound materials according to any one of claims 1 to 6.

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