Vulcanized phenazine organic matter with linear structure as well as preparation method and application thereof

Abstract

The invention discloses a sulfide phenazine organic matter with a linear structure and a preparation method and application thereof, and the preparation method specifically comprises the following steps: in an inert gas atmosphere, adding 2, 7-dibromophenazine and sodium sulfide nonahydrate into an organic solvent, and under a heating condition, continuously stirring the reaction mixture in a reflux state for reaction; after the reaction, centrifugally washing a solid product and drying to obtain a sulfide phenazine organic matter with a linear structure; in the obtained organic matter, phenazine is mutually connected through a stable thioether bond to form a chain-shaped linear structure. The organic matter prepared by the method has rich redox active sites, a good conjugate structure and a stable organic framework, and when the organic matter is used as a capacitive deionization electrode material, the organic matter shows high specific capacity and good cycle stability.

Description

Technical Field

[0001] The present invention relates to a phenazine sulfide organic compound with a linear structure, and also relates to a preparation method of the phenazine sulfide organic compound and application of the phenazine sulfide organic compound as a capacitor deionization electrode material. Background Art

[0002] Capacitive deionization technology (CDI) has been widely used in the treatment of ammonia nitrogen wastewater, especially the removal of ammonium ions, due to its advantages of low energy consumption, high efficiency, easy regeneration, simple maintenance, low cost and no secondary pollution.

[0003] Currently, although inorganic materials are often used as capacitive deionization electrode materials, their slow desalination rate when removing ammonium ions and limited theoretical energy storage capacity seriously restrict their performance. Moreover, the widespread use of inorganic materials also complicates the manufacturing and recycling processes. In comparison, organic electrode materials have the advantages of natural sustainability, biodegradability, low carbon and environmental protection, and low cost. Many organic materials can be extracted from nature or biomass, and their energy storage capacity can be controlled through molecular design, thereby improving their electrochemical performance.

[0004] However, in the prior art, organic electrode materials are generally conductive polymers, such as polypyrrole (PPy), polyaniline (PANI) or polythiophene (PTh). Organic small molecules, such as quinones (such as para-benzoquinone, naphthoquinone), carbazole or triazine derivatives, etc. The above-mentioned organic materials are prone to irreversible structural changes during the oxidation / reduction process, especially conductive polymers are prone to degradation or chain breakage during the cycle. Organic small molecules have solubility problems in the electrolyte, resulting in the loss of active substances and poor cycle stability. In addition, due to the lack of long-range π-conjugated structure or lack of regular arrangement or crystallinity in the structure, the electron transfer efficiency is low and the overall conductivity is poor.

[0005] Therefore, the organic electrode materials in the existing technology still have deficiencies in structural stability and electrical conductivity, and are prone to side reactions in electrochemical reactions, resulting in a decrease in theoretical capacitance, shortened cycle life and poor rate performance, which limits their effectiveness in practical applications. Summary of the Invention

[0006] Purpose of the invention: The purpose of the present invention is to provide a linear phenazine sulfide organic compound with good structural stability, high specific capacity and high conductivity. When used as a capacitor deionization electrode material, it not only has good ammonium ion removal ability but also has good cyclic stability. Another purpose of the present invention is to provide a preparation method of the above-mentioned phenazine sulfide organic compound and its application as a capacitor deionization electrode material.

[0007] Technical solution: The method for preparing a linear phenazine sulfide organic compound described in the present invention specifically comprises: adding 2,7-dibromophenazine and sodium sulfide nonahydrate to an organic solvent in an inert gas atmosphere; and continuously stirring the reaction mixture under heating conditions while reflux. After the reaction, the solid product is centrifuged, washed, and dried to obtain a linear phenazine sulfide organic compound; in the obtained organic compound, the phenazines are interconnected by stable thioether bonds to form a chain-like linear structure.

[0008] Wherein, the inert gas is nitrogen and / or argon.

[0009] The molar ratio of 2,7-dibromophenazine to sodium sulfide nonahydrate is 1 to 3:1.

[0010] Wherein, the organic solvent is N-methylpyrrolidone.

[0011] Wherein, the heating temperature is 150-200° C., and the reaction time is 6-8 hours.

[0012] Among them, the linear phenazine sulfide organic compound prepared by the above method has the structural formula:

[0013]

[0014] Among them, the above-mentioned linearly structured phenazine sulfide organic compound is used as a capacitor deionization electrode material.

[0015] The electrode material is prepared by the following method: mixing phenazine sulfide organic matter, conductive additive and adhesive in a mass ratio of 7-8:1-2:1, grinding after mixing to obtain slurry; and evenly coating the slurry on the surface of conductive carbon paper to obtain electrode material.

[0016] The principle of the present invention is as follows: the present invention uses phenazine halide and sodium sulfide as reagents, and uses sulfur atoms to connect aromatic rings in one step; the phenazines in the obtained organic matter are connected to each other through stable sulfide bonds to form a chain linear structure, which can effectively improve the electrical conductivity of the organic matter (through sulfur atom bridging, an extended π-conjugated main chain is formed between the phenazine units, and the sulfur atom participates in electron delocalization and reduces the torsion angle of the molecular main chain, thereby broadening the electron transmission channel; at the same time, the large polarizability and lone pair electrons of the sulfur atom can promote charge migration and increase the carrier concentration; finally, the chain linear structure is conducive to the orderly stacking of molecules and the construction of a continuous electron pathway. These factors synergistically improve the electrical conductivity of the material); at the same time, it also provides rich redox sites, thereby obtaining a higher specific capacity; at the same time, the sulfide bond makes the connection of the phenazine chain more stable, so that the organic matter is not easy to have side reactions in the electrochemical reaction, thereby improving the cycle stability performance. The organic matter prepared by the present invention has rich redox active sites, good conjugated structure and stable organic skeleton. When the organic matter is used as a capacitor deionization electrode material, it exhibits high specific capacity and good cycle stability. The improvement of conductivity can reduce the resistance of electrodes and interfaces, thereby accelerating the transfer rate of charges / ions; the improvement of specific capacity means that the unit mass of electrode can store more charge, achieving higher ion adsorption capacity and coulombic efficiency. The synergistic effect of the two not only improves the NH4 + The removal rate is improved, and the removal volume and energy efficiency are enhanced.

[0017] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: (1) The present invention introduces sulfur atoms into the phenazine unit and utilizes sulfide bonds to stabilize the structure of phenazine. The polymer based on the sulfide bridge bond is completely insoluble in any solvent, effectively avoiding unnecessary dissolution and helping to improve the recyclability of the material during application. (2) At the same time, the present invention enhances the conductivity of organic matter by introducing sulfur atoms, providing it with more abundant redox active sites, thereby achieving a higher specific capacity. When used as an electrode material for desalination of ammonia nitrogen wastewater in capacitive deionization, it has good removal ability for ammonium ions (strong desalination ability). BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the NMR 1H spectrum of the sulfide phenazine organic compound prepared in Example 1;

[0019] Figure 2 This is the XPS carbon spectrum (C1s) of the sulfide phenazine organic compound prepared in Example 1;

[0020] Figure 3 This is the XPS nitrogen spectrum (N1s) of the sulfide phenazine organic compound prepared in Example 1;

[0021] Figure 4This is the XPS sulfur spectrum (S2p) of the sulfide phenazine organic compound prepared in Example 1;

[0022] Figure 5 The cyclic voltammetry (CV) curves at different scan rates when the phenazine sulfide organic compound prepared in Example 1 is used as a capacitive deionization electrode material;

[0023] Figure 6 The figure shows the charge-discharge curves (GCD) at different current densities when the phenazine sulfide organic compound prepared in Example 1 is used as a capacitor deionization electrode material;

[0024] Figure 7 Specific capacity diagrams at different current densities when the organic materials prepared in Examples 1 to 4 are used as capacitor deionization electrode materials;

[0025] Figure 8 Specific capacity diagrams at different current densities when the organic materials prepared in Comparative Examples 1 to 6 are used as capacitor deionization electrode materials;

[0026] Figure 9 This is a conductivity curve of the phenazine sulfide organic compound prepared in Example 1 in a 10 mmol ammonium chloride solution when used as a capacitive deionization electrode material;

[0027] Figure 10 This is a comparison chart of the desalination capabilities of the organic materials prepared in Examples 1 to 4 and Comparative Examples 1 to 6 in a 10 mmol ammonium chloride solution when used as capacitive deionization electrode materials. DETAILED DESCRIPTION

[0028] Example 1

[0029] The method for preparing a phenazine sulfide organic compound with a linear structure comprises the following steps: adding 0.3379 g (1 mmol) of 2,7-dibromophenazine, 0.2405 g (1 mmol) of sodium sulfide nonahydrate, and 25 mL of N-methylpyrrolidone (NMP) to a reactor under nitrogen protection; continuously stirring the reaction mixture for reaction under reflux, the reaction temperature being 200° C., and the reaction time being 8 hours; after the reaction is completed, stopping heating, cooling to room temperature, centrifuging and washing a solid product, washing it four times with acetone, ethanol, and water respectively, and drying the product obtained after centrifugation and washing to obtain a phenazine sulfide organic compound with a linear structure.

[0030] The chemical reaction equation of the above method is as follows:

[0031]

[0032] like Figure 1As shown, according to the spectrum and the structure of the compound, the signals in the 1H nuclear magnetic spectrum of the sulfide phenazine organic compound obtained in Example 1 can be attributed as follows: the spectrum shows that the chemical shift range is 7.4-8.6ppm, which are all hydrogen signals on the aromatic ring. The strongest signal in the center (about 8.0ppm) is attributed to the hydrogen atoms at the a and d positions. Due to the symmetry of the molecule, these hydrogens are in an equivalent environment and have the same chemical shift. The signal of about 8.3ppm is attributed to the hydrogen at the c and f positions, which are affected by the deshielding effect of the adjacent sulfur atoms. The lowest field signal (about 7.5ppm) is attributed to the hydrogen at the b and e positions, which are in a relatively shielded environment and are less affected by the sulfur atoms. The shape of the peak shows slight splitting, indicating that there is a certain coupling effect between the aromatic hydrogens. The overall peak width may be related to intermolecular interactions or solvent effects. The electronic effects of nitrogen and sulfur atoms significantly affect the chemical shift of each hydrogen atom, and the signal attribution is consistent with the structure of the compound.

[0033] Figure 2 The XPS carbon spectrum (C 1s) of the sulfide phenazine organic compound prepared in Example 1 shows that the peak near 284.6 eV corresponds to the aromatic ring and carbon-carbon single bond (C=C / CC), the peak near 285.6 eV is attributed to the CN / C=N bond in phenazine, the peak at 286.3 eV reflects the C-S chemical bond brought by sulfur doping, and the peak at 290 eV reflects the π-π * The satellite peaks indicate that the molecule has an extensive conjugated system.

[0034] Figure 3 The XPS nitrogen spectrum (N 1s) of the sulfide phenazine organic compound prepared in Example 1 shows two main peaks at 399.2 eV and 398.2 eV, corresponding to the C=N and CN bonds of the polymer, respectively. Figure 2 XPSC1s spectrum analysis showed that the C=N and CN bonds originated from the phenazine structure, proving that the organic compound of the present invention successfully formed a structure in which multiple phenazines were connected.

[0035] Figure 4 The XPS sulfur spectrum (S2p) of the sulfide phenazine organic compound prepared in Example 1 has two main peaks in the range of 158eV to 172eV, corresponding to S2P 3 / 2 and S2P 1 / 2 These two peaks are the result of the spin-orbit coupling splitting of the sulfur 2p orbital. 3 / 2 and S2P 1 / 2 The peak position difference is typically around 1.2 eV, a typical characteristic of sulfur. For linear phenazine sulfide organic compounds, the sulfur atom typically forms a C-S bond with the carbon atom. The C-S bond binding energy is typically in the range of 163-165 eV, indicating that the sulfur atom forms a stable C-S bond with the carbon atom in the phenazine ring.

[0036] Example 2

[0037] The method for preparing a phenazine sulfide organic compound with a linear structure comprises the following steps: adding 0.50685 g (1.5 mmol) of 2,7-dibromophenazine, 0.2405 g (1 mmol) of sodium sulfide nonahydrate, and 25 mL of N-methylpyrrolidone (NMP) to a reactor under nitrogen protection; continuously stirring the reaction mixture for reaction under reflux, the reaction temperature being 150° C., and the reaction time being 6 hours; after the reaction is completed, stopping heating, cooling the reaction mixture to room temperature, washing the solid product by centrifugation, washing the solid product with acetone, ethanol, and water four times each, and drying the product obtained after centrifugation and washing to obtain the phenazine sulfide organic compound with a linear structure.

[0038] Example 3

[0039] The method for preparing a phenazine sulfide organic compound with a linear structure comprises the following steps: adding 0.6758 g (2 mmol) of 2,7-dibromophenazine, 0.2405 g (1 mmol) of sodium sulfide nonahydrate, and 25 mL of N-methylpyrrolidone (NMP) to a reactor under nitrogen protection; continuously stirring the reaction mixture for reaction under reflux, the reaction temperature being 200° C., and the reaction time being 8 hours; after the reaction is completed, stopping heating, cooling to room temperature, washing a solid product by centrifugation, washing with acetone, ethanol, and water four times each, and drying the product obtained after centrifugation and washing to obtain a phenazine sulfide organic compound with a linear structure.

[0040] Example 4

[0041] The method for preparing a phenazine sulfide organic compound with a linear structure comprises the following steps: adding 1.0137 g (3 mmol) of 2,7-dibromophenazine, 0.2405 g (1 mmol) of sodium sulfide nonahydrate, and 25 mL of N-methylpyrrolidone (NMP) to a reactor under nitrogen protection; continuously stirring the reaction mixture for reaction under reflux, the reaction temperature being 200° C., and the reaction time being 8 hours; after the reaction is completed, stopping heating, cooling to room temperature, centrifuging and washing a solid product, washing it four times with acetone, ethanol, and water respectively, and drying the product obtained after centrifugation and washing to obtain a phenazine sulfide organic compound with a linear structure.

[0042] Comparative Example 1

[0043] The preparation method of Comparative Example 1 is the same as that of Example 1, with the only difference being that 2,6-dibromoanthracene is used instead of 2,7-dibromophenazine to obtain a polyanthryl sulfide polymer.

[0044] The chemical reaction equation is as follows:

[0045]

[0046] Comparative Example 2

[0047] The preparation method of Comparative Example 2 is the same as that of Example 1, with the only difference being that 2,6-dibromoanthraquinone is used to replace 2,7-dibromophenazine to obtain a poly-2,6-anthraquinone-based sulfide polymer.

[0048] The chemical reaction equation is as follows:

[0049]

[0050] Comparative Example 3

[0051] The preparation method of Comparative Example 3 is the same as that of Example 1, except that 1,5-dibromoanthraquinone is used to replace 2,7-dibromophenazine to obtain a poly-1,5-anthraquinone-based sulfide polymer.

[0052] The chemical reaction equation is as follows:

[0053]

[0054] Comparative Example 4

[0055] The preparation method of Comparative Example 4 is the same as that of Example 1, except that acetic acid is used instead of N-methylpyrrolidone.

[0056] Comparative Example 5

[0057] The preparation method of Comparative Example 5 is the same as that of Example 1, with the only difference being that the heating temperature is 100°C.

[0058] Comparative Example 6

[0059] The preparation method of Comparative Example 6 is the same as that of Example 1, with the only difference being that the heating process time is 4 h.

[0060] The phenazine sulfide organic compounds prepared in Examples 1 to 4 and Comparative Examples 1 to 6 were used as capacitor deionization electrode materials. The specific application process was as follows:

[0061] Before electrode preparation, the dried phenazine sulfide organic matter was ground in a mortar to ensure uniform mixing; the phenazine sulfide organic matter, carbon nanotubes and polyvinylidene fluoride binder were mixed in a mass ratio of 7:2:1 and dispersed in 1-methyl-2-pyrrolidone. The mixture was stirred in a high-speed blender for 30 minutes to form a uniform slurry; the slurry was then evenly hung on carbon cloth and vacuum dried at 60°C for 12 hours to form an organic electrode sheet; the electrode sheet was used as the negative electrode of a capacitive deionization capacitor, with activated carbon as the positive electrode, and tested in a 10mmol ammonium chloride solution.

[0062] pass Figures 5-6 It can be seen that the sulfide phenazine linear structure organic electrode prepared in Example 1 has two pairs of redox peaks, and at 1Ag-1 The specific capacity is 192.65 mAh g -1 .

[0063] Figure 7 The specific capacity diagram of the organic matter prepared in Examples 1 to 4 at different current densities in 1 mol ammonium chloride solution when used as a capacitor deionization electrode material. The specific capacity diagram of Examples 2 to 4 at 1 Ag -1 The specific capacities under the conditions are 166.54, 153.65, and 141.75 mAh g -1 .

[0064] Figure 8 The specific capacity diagram of the organic compounds prepared in Comparative Examples 1 to 6 at different current densities in 1 mol ammonium chloride solution when used as capacitor deionization electrode materials. -1 The specific capacities under these conditions are 50.34, 111.45, 148.67, 171.36, 121.54, and 100.54 mAh g -1 .

[0065] Figure 9 The conductivity curve of the sulfide phenazine linear organic electrode material prepared in Example 1 in a 10 mmol ammonium chloride solution is shown. By calculating the concentration change of the ammonium chloride solution, the maximum desalination capacity is calculated to be 213.88 mg g -1 .

[0066] from Figure 10 It can be seen that after reacting in 10 mmol ammonium chloride solution for 8 h, the sulfide phenazine linear structure organic compound prepared in Example 1 has the strongest desalination ability and the highest desalination capacity when used as a capacitive deionization electrode material, reaching 213.88 mg g -1 The desalination rates of Examples 2 to 4 were 142.04, 147.31, and 115.37 mg g, respectively. -1 The desalination rates of Comparative Examples 1 to 6 were 47.88, 96.44, 128.29, 173.09, 97.29, and 84.11 mg g -1 mg g -1 .

Claims

1. A method for preparing a linear phenazine sulfide organic compound, characterized in that: Specifically, 2,7-dibromophenazine and a sulfur source are added to an organic solvent in an inert gas atmosphere. Under heating conditions, the reaction mixture is continuously stirred and reacted under reflux. After the reaction, the solid product is centrifuged, washed, and dried to obtain a sulfide phenazine organic compound with a linear structure. In the obtained organic compound, the phenazines are connected to each other through stable thioether bonds to form a chain-like linear structure.

2. The preparation method according to claim 1, wherein: The inert gas is nitrogen and / or argon.

3. The preparation method according to claim 1, wherein: The molar ratio of the 2,7-dibromophenazine to the sulfur source is 1 to 3:

1.

4. The preparation method according to claim 3, wherein: The sulfur source is sodium sulfide nonahydrate or lithium sulfide.

5. The preparation method according to claim 1, wherein: The organic solvent is N-methylpyrrolidone or N,N-dimethylformamide.

6. The preparation method according to claim 1, wherein: The heating temperature is 150-200° C., and the reaction time is 6-8 hours.

7. The sulfide phenazine organic compound with a linear structure obtained by the method of claim 1, characterized in that: The structural formula is:

8. Use of the linear phenazine sulfide organic compound according to claim 7 as a capacitor deionization electrode material.

9. The use according to claim 8, characterized in that: The electrode material is prepared by the following method: phenazine sulfide organic matter, a conductive additive and an adhesive are mixed in a mass ratio of 7 to 8:1 to 2:1, and then ground to obtain a slurry; the slurry is evenly coated on the surface of a conductive carbon paper to obtain the electrode material.

10. The use according to claim 9, characterized in that: The conductive additive is carbon nanotube or acetylene black.

Images