Organic small molecule containing nitro conjugated phenazine structure as well as preparation method and application of organic small molecule

Abstract

The invention relates to the technical field of capacitive deionization, in particular to an organic small molecule containing a nitro-conjugated phenazine structure as well as a preparation method and application of the organic small molecule. The small organic molecule containing the nitro-conjugated phenazine structure is prepared by taking hexaketocyclohexane and 4-nitro-o-phenylenediamine as raw materials and carrying out reflux reaction through an acetic acid solvent under the protection of inert gas through optimized reaction conditions (reflux for 12 hours at 120 DEG C), has a stable aromatic conjugated skeleton and a nitro electron-deficient active center, and has the advantages that the structure is simple, the reaction is stable, and the yield is high. The selective adsorption capacity on ammonium ions (NH4 +) in wastewater is obviously improved. When the material is used as a CDI electrode, the material shows high specific capacity, excellent cycle performance and conductivity, the problem that a traditional carbon-based material is low in NH4 < + > adsorption efficiency is solved, and a novel efficient electrode material is provided for nitrogen pollution wastewater treatment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of capacitive deionization, and particularly relates to an organic small molecule containing a nitro-conjugated phenoxazine structure and a preparation method and application thereof. BACKGROUND

[0002] With the increasing pollution of water resources, efficient removal and resource utilization of nitrogen pollutants have become one of the important challenges faced by current water treatment technology. Ammonium ion (NH4 + ) as the main form of nitrogen, widely exists in municipal wastewater, livestock and poultry breeding wastewater and fertilizer production wastewater. Its accumulation in water bodies will destroy the ecological balance, lead to water quality deterioration, and even endanger drinking water safety. Therefore, how to realize effective recovery and utilization of NH4 + while ensuring environmental safety has become a key issue of sustainable management of water resources.

[0003] At present, the mainstream methods for separation and enrichment of NH4 + include chemical precipitation, membrane separation, ion exchange, etc., but these technologies generally have problems such as high operation cost, large energy consumption, complex equipment and secondary pollution, which are difficult to balance environmental friendliness and economy. In recent years, electrically driven separation technology has attracted widespread attention due to its simple operation, green controllability and material adjustability, among which capacitive deionization (CDI) technology is considered as a promising water treatment method due to its low energy consumption, easy regeneration and no addition of additives. CDI technology realizes physical removal of target ions by driving ion migration and storing in the electrode interface through an external electric field. In this system, the structure and surface chemical properties of the electrode material directly determine its ion adsorption performance. For example, patent technology document CN113830866B discloses a capacitive deionization electrode material and a preparation method thereof. The electrode material of the present application has higher specific surface area, good pore structure and mechanical strength, and good electrical conductivity, and is excellent in performance as an electrode.

[0004] However, traditional carbon-based materials have obvious limitations in selective adsorption of specific ions, especially when facing small molecular size and strong hydrophilic NH4 + , the adsorption efficiency and selectivity need to be improved. SUMMARY

[0005] Therefore, the purpose of the present application is to provide an organic small molecule containing a nitro-conjugated phenoxazine structure and a preparation method and application thereof, so as to solve the problem of poor adsorption of NH4 + when traditional carbon-based materials are used as electrodes.

[0006] Based on the above purpose, the application provides an organic small molecule containing a nitro-conjugated phenazine structure, and a structural formula is as follows:

[0007]

[0008] The application further provides a preparation method of the organic small molecule containing the nitro-conjugated phenazine structure, and specific steps are as follows:

[0009] In an inert gas atmosphere, hexaketocyclohexane, 4-nitro-o-phenylenediamine and an organic solvent are mixed, stirred uniformly, and then refluxed at 120 DEG C for 12 hours; after the reaction is completed, the mixture is cooled to room temperature, centrifuged, washed and dried to obtain the organic small molecule containing the nitro-conjugated phenazine structure.

[0010] Preferably, the hexaketocyclohexane compound is hexaketocyclohexane.

[0011] Preferably, the organic solvent is acetic acid.

[0012] Preferably, the washing is sequentially performed with hot acetic acid, acetone, deionized water and ethanol.

[0013] Preferably, the drying is vacuum drying at 80 DEG C.

[0014] Further, the application further provides an application of the organic small molecule containing the nitro-conjugated phenazine structure, which is applied to adsorbing ammonium ions in wastewater.

[0015] The application has the following beneficial effects:

[0016] The application introduces a nitro compound as a main active center of an electron-deficient unit into a phenazine structure to form an organic aromatic conjugated structure, has rich redox active sites, a high conjugated structure and a stable organic skeleton, inhibits the dissolution of an organic electrode material in an electrolyte, and can obtain high specific capacity and stable cycle performance when applied to an electrode material for capacitive deionization, and thus has great potential as a high-performance organic electrode material.

[0017] The application prepares a novel organic electrode material with a multi-phenazine structure, the introduction of the phenazine can optimize the electronic structure of the organic material, provide more redox active energy storage sites for the electrode, improve the intrinsic conductivity, and also can have high specific capacity.

[0018] The application successfully constructs the organic small molecule containing the nitro-conjugated phenazine structure through precise molecular structure design and control of specific reaction conditions, and innovatively finds that the adsorption performance of the organic small molecule without a nitro-substituted conjugated phenazine structure is obviously not good, and the organic small molecule containing the nitro-conjugated phenazine structure obtained from 4-nitro-o-phenylenediamine has the best adsorption capacity. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in this invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0020] Figure 1 The image shows the cyclic voltammetry curves of the electrode sheet containing the nitro-conjugated phenazine structure of the organic small molecule prepared in Example 1 of the present invention at different scan rates.

[0021] Figure 2 This is a charge-discharge curve of an electrode sheet containing an organic small molecule with a nitro-conjugated phenazine structure under different current densities, as shown in Example 1 of the present invention.

[0022] Figure 3 Examples 1-6 of this invention and Comparative Examples 1 and 2 show the specific capacity curves of the electrode sheets containing organic small molecules with nitroconjugated phenazine structures.

[0023] Figure 4 This is a graph showing the change in conductivity of the conductive carbon cloth containing nitro-conjugated phenazine organic small molecules prepared in Example 1 of the present invention during the adsorption and desorption process in 10mM NH4Cl electrolyte under different voltage conditions.

[0024] Figure 5 The LUMO energy level diagrams are for the small organic molecules containing nitro-conjugated phenazine structures in Examples 1 and 2 of this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0026] Example 1: An organic small molecule containing a nitro-conjugated phenazine structure, the specific preparation steps are as follows:

[0027] Under a nitrogen atmosphere, 0.4995 mg of hexaketonecyclohexane and 0.7596 mg of 4-nitro-o-phenylenediamine were dissolved in 50-60 mL of acetic acid. After thorough mixing, the mixture was refluxed in an oil bath at 120 °C for 12 h. After the reaction was completed, the mixture was cooled to room temperature. The resulting product was centrifuged and washed twice each with hot acetic acid, acetone, and deionized water, followed by three washes with ethanol. Finally, it was vacuum dried at 80 °C to obtain a small organic molecule containing a nitro-conjugated phenazine structure. The specific reaction equation is as follows:

[0028]

[0029] Example 2: An organic small molecule containing a nitro-conjugated phenazine structure, the specific preparation steps are as follows:

[0030] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 120°C oil bath for 12h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, and deionized water for 2 times, respectively, and then washed with ethanol for 3 times. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing nitro-conjugated phenazine structure.

[0031] Example 3: An organic small molecule containing nitro-conjugated phenazine structure, and the specific preparation steps are as follows:

[0032] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 160°C oil bath for 12h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, and deionized water for 2 times, respectively, and then washed with ethanol for 3 times. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing nitro-conjugated phenazine structure.

[0033] Example 4: An organic small molecule containing nitro-conjugated phenazine structure, and the specific preparation steps are as follows:

[0034] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 120°C oil bath for 24h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, and deionized water for 2 times, respectively, and then washed with ethanol for 3 times. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing nitro-conjugated phenazine structure.

[0035] Example 5: An organic small molecule containing nitro-conjugated phenazine structure, and the specific preparation steps are as follows:

[0036] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 140°C oil bath for 24h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, and deionized water for 2 times, respectively, and then washed with ethanol for 3 times. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing nitro-conjugated phenazine structure.

[0037] Example 6: An organic small molecule containing nitro-conjugated phenazine structure, and the specific preparation steps are as follows:

[0038] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 160°C oil bath for 24h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, deionized water, and ethanol for 2 times and 3 times, respectively. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing a nitro-conjugated phenazine structure.

[0039] Comparative Example 1: An organic small molecule containing a nitro-conjugated phenazine structure, and the specific preparation steps are as follows:

[0040] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 160°C oil bath for 24h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, deionized water, and ethanol for 2 times and 3 times, respectively. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing a nitro-conjugated phenazine structure, and the specific reaction equation is as follows:

[0041]

[0042] Comparative Example 2: An organic small molecule containing a conjugated phenazine structure, and the specific preparation steps are as follows:

[0043] Under the atmosphere of nitrogen, 0.4995mg hexaketide cyclohexane and 0.7596mg 4-nitro-o-phenylenediamine were dissolved in 50-60mL acetic acid, mixed uniformly, and then refluxed at 160°C oil bath for 24h. After the reaction was completed, the product was cooled to room temperature, centrifuged, and then washed with hot acetic acid, acetone, deionized water, and ethanol for 2 times and 3 times, respectively. Finally, the product was dried at 80°C under vacuum to obtain an organic small molecule containing a nitro-conjugated phenazine structure, and the specific reaction equation is as follows:

[0044]

[0045] Performance test

[0046] The organic small molecule materials obtained in Examples 1-6 and Comparative Examples 1, 2 were ground in a mortar, then dispersed in 1-methyl-2-pyrrolidone in a mass ratio of 8:1:1 with acetylene and polyvinylidene fluoride, ground to form a uniform slurry, and the obtained slurry was uniformly coated on conductive carbon paper, and finally vacuum dried at 60°C for 12h to obtain organic small molecule electrode sheets containing conjugated phenazine structures for working electrodes, and the obtained electrode sheets were subjected to electrochemical performance testing; the organic small molecule electrode sheets containing conjugated phenazine structures for working electrodes prepared above were subjected to electrochemical testing in a 1M NH4Cl electrolyte using a three-electrode system with an electrochemical workstation, and the test results are shown in Figures 1-3 .

[0047] The organic small molecule materials obtained in Examples 1-6 and Comparative Examples 1, 2 were ground in a mortar, then dispersed in 1-methyl-2-pyrrolidone in a mass ratio of 8:1:1 with acetylene and polyvinylidene fluoride, ground to form a uniform slurry, and the obtained slurry was uniformly coated on conductive carbon cloth, and finally vacuum dried at 60°C for 12h to obtain conductive carbon cloth containing conjugated phenazine structures for working electrodes, and subjected to capacitive deionization performance testing, and the test results are shown in Table 1.

[0048] Desalination testing (15min) was performed in a capacitive deionization system using an electrochemical workstation in a 10mM NH4Cl electrolyte, and the test results are shown in Figure 4 .

[0049] Table 1. Capacitive deionization performance test results

[0050] Experiment No. Initial adsorption capacity (mg.g -1 )]]> Example 1 194.3 Example 2 139.1 Example 3 131.5 Example 4 147.7 Example 5 130.6 Example 6 125.8 Comparative Example 1 124.9 Comparative Example 2 96.9

[0051] As can be seen from Table 1, the initial adsorption capacity of the conductive carbon cloth containing nitro-substituted conjugated phenazine structure organic small molecules prepared in Example 1 is higher than that of other examples; Examples 1, 2, and 4 show that refluxing at 120°C for 12h is the best reaction condition; Examples 2, 5, and 6 show that the initial adsorption capacity of ammonium ions does not significantly increase with the extension of reaction time and the increase of reaction temperature; Examples 1 and Comparative Examples 1, 2 show that the nitro-substituted conjugated phenazine structure organic small molecules and the conjugated phenazine structure organic small molecules without nitro substitution at different positions have a great influence on their adsorption performance. In comparison, the nitro-substituted conjugated phenazine structure organic small molecules prepared in Example 1 have the best adsorption performance for ammonium ions.

[0052] As can be seen from Figure 1 , there are two pairs of obvious redox peaks, indicating that it has good redox properties.

[0053] As can be seen from Figure 2 , the current density is 1Ag-1 The specific capacity of small organic molecules containing nitroconjugated phenazine structures is approximately 202 mAh g. -1 And at 50Ag -1 There is still 71mAh g. -1 The specific capacity indicates that it has good rate performance.

[0054] from Figure 3 As can be seen from the data, the small organic molecules containing nitro-conjugated phenazine structures prepared in Example 1 have a 1Ag content of [missing information]. -1 The specific capacity is approximately 202 mAh g. -1 And at 50Ag -1 There is still 95mAh g -1 The specific capacity of the organic small molecules with nitro-conjugated phenazine structures prepared in Examples 2-6 and Comparative Examples 1 and 2 is significantly better than that of the organic small molecules with nitro-conjugated phenazine structures prepared in Examples 2-6 and Comparative Examples 1 and 2, which again demonstrates its good rate performance.

[0055] from Figure 4 As can be seen from the results, the small organic molecules containing nitro-conjugated phenazine structures prepared in Example 1 exhibited relatively rapid capacitive deionization capabilities under different voltage conditions.

[0056] from Figure 5 As can be seen from the results, the LUMO energy level of the organic small molecule containing the nitro-conjugated phenazine structure prepared in Example 1 is much lower than that of Comparative Examples 1 and 2, indicating that its electron-binding ability is superior to the other two materials, thus exhibiting good adsorption properties.

[0057] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A small organic molecule containing a nitro-conjugated phenazine structure, characterized in that, The structural formula is as follows:

2. A method for preparing an organic small molecule containing a nitro-conjugated phenazine structure according to claim 1, characterized in that, Includes the following steps: In an inert gas atmosphere, hexaketone cyclohexane compounds, 4-nitro-o-phenylenediamine, and organic solvents were mixed and stirred until homogeneous. The mixture was then refluxed at 120°C for 12 hours. After the reaction was completed, the mixture was cooled to room temperature, centrifuged, washed, and dried to obtain small organic molecules containing nitro-conjugated phenazine structures.

3. The preparation method according to claim 2, characterized in that, The hexagonal cyclohexane compound is hexagonal cyclohexane.

4. The preparation method according to claim 2, characterized in that, The organic solvent is acetic acid.

5. The preparation method according to claim 2, characterized in that, The washing process involves sequentially washing with hot acetic acid, acetone, deionized water, and ethanol.

6. The preparation method according to claim 2, characterized in that, The drying process is performed under vacuum at 80°C.

7. An application of an organic small molecule containing a nitro-conjugated phenazine structure according to claim 1, characterized in that, It is used to adsorb ammonium ions in wastewater.

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