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CN-117383560-B - Preparation method and application of high-nitrogen-content nitrogen-doped porous carbon with multiple nitrogen-rich units

CN117383560BCN 117383560 BCN117383560 BCN 117383560BCN-117383560-B

Abstract

The invention discloses a preparation method and application of nitrogen-doped porous carbon with multiple nitrogen-rich units and high nitrogen content, and belongs to the field of porous carbon materials. The invention uses triazine containing three alkynyl groups as a crosslinking center and pyrazine containing double azido groups as a crosslinking arm, and the triazine is formed into a triazole structure through click chemistry reaction, so that the nitrogen-doped porous polymer with multiple nitrogen-rich units is constructed, the N content is controllable and high, the distribution is uniform, the stability of the N-containing structure is high, the N residue of the porous polymer after activation and carbonization treatment is higher, the CO 2 adsorption selectivity of the porous carbon is further improved, the nitrogen-doped porous polymer is subjected to activation and carbonization treatment to prepare the nitrogen-doped porous carbon with multiple nitrogen-rich units and high nitrogen content, and the nitrogen-doped porous carbon has high yield, adsorption capacity, selectivity and reusability and wide application prospects in the fields of adsorption, catalysis, membrane separation and the like.

Inventors

  • ZHONG JING
  • LI PEILIN
  • MA WENZHONG

Assignees

  • 常州大学

Dates

Publication Date
20260505
Application Date
20231031

Claims (8)

  1. 1. The preparation method of the nitrogen-doped porous carbon with multiple nitrogen-rich units and high nitrogen content is characterized by comprising the following steps of: Uniformly mixing a multi-nitrogen-rich porous organic polymer with an activating agent, placing the mixture in 80 o C for vacuum drying 12h, carbonizing the mixture in N 2 atmosphere, cooling the carbonized mixture to room temperature, washing the carbonized mixture with 5 mol/L HCl and deionized water until the pH value of filtrate is 7, and drying the washed mixture to obtain the high-nitrogen-content nitrogen-doped porous carbon with multi-nitrogen-rich units; the multi-nitrogen-rich porous organic polymer is prepared from triazine containing three alkynyl groups and pyrazine containing double azido groups through click chemical reaction to form a triazole structure, wherein the chemical formula of the triazine containing three alkynyl groups is as follows: The chemical formula of the pyrazines containing the bisazide group is ; The activator is potassium hydroxide, zinc chloride or ferric chloride; The application of the nitrogen-doped porous carbon material with multiple nitrogen-rich units in the CO 2 adsorption and separation aspect.
  2. 2. The method for preparing the nitrogen-doped porous carbon material with multiple nitrogen-rich units and high nitrogen content according to claim 1, wherein the specific preparation method of the porous organic polymer with multiple nitrogen-rich units is as follows: The preparation method comprises the steps of mixing triazine containing three alkynyl groups, pyrazine containing double azido groups and Pd (PPh 3 ) 4 、CuI、i-Pr 2 NH according to the mass ratio of 1:1.5-3:1-2:0.5-2:1-5), dissolving in THF, reacting under the atmosphere of N 2 and the temperature of 60-120 o ℃ for 6-24 h, cooling to room temperature, pouring the reaction mixture into ethyl acetate, washing an organic layer with 5wt% HCl, saturated NaHCO 3 and saturated NaCl solution in sequence, drying and filtering with MgSO 4 , and evaporating the solvent under reduced pressure to obtain the multi-nitrogen-enriched porous organic polymer.
  3. 3. The method for preparing the nitrogen-doped porous carbon material with multiple nitrogen-rich units and high nitrogen content as claimed in claim 2, wherein the specific preparation method of the triazine containing the trialkynyl group is as follows: (1) After evenly mixing cyanuric chloride, pdCl 2 (PPh 3 ) 2 , cuI and triethylamine, adding trimethylethynyl silicon under the atmosphere of N 2 , stirring at 80 o ℃ for reaction for 24h, then adding methylene dichloride for dilution, filtering by diatomite, extracting filtrate with CH 2 Cl 2 and water, washing with saturated NaCl, drying with anhydrous Na 2 SO 4 , and spin-drying to obtain a compound 1; (2) Compound 1 was dissolved in methanol, then K 2 CO 3 was added, stirred at room temperature for 4: 4h, dried by spin-drying, the organic phase was extracted with water and CH 2 Cl 2 , washed with saturated NaCl, dried over anhydrous Na 2 SO 4 , and dried by spin-drying to give a triazine containing a tricynyl group.
  4. 4. The method for preparing the nitrogen-doped porous carbon material with multiple nitrogen-rich units and high nitrogen content according to claim 3, wherein the mass ratio of cyanuric chloride, pdCl 2 (PPh 3 ) 2 , cuI, triethylamine and trimethylethynyl silicon is 1:0.1-1:0.05-0.5:1-2:2-10.
  5. 5. The method for preparing the nitrogen-doped porous carbon material with multiple nitrogen-rich units and high nitrogen content as claimed in claim 2, wherein the specific preparation steps of the pyrazine containing the bisazide group are as follows: dissolving potassium azide and pyrazine chloride in DMF, stirring at 60 o C for 24: 24h, cooling to room temperature, pouring the reaction mixture into deionized water, filtering, washing, dissolving in chloroform, drying over magnesium sulfate, filtering, and evaporating the solvent to obtain the pyrazine containing the bisazide group.
  6. 6. The preparation method of the nitrogen-doped porous carbon material with multiple nitrogen-rich units, which is characterized by comprising the step of preparing the porous carbon material with multiple nitrogen-rich units, wherein the mass ratio of potassium azide to pyrazine chloride is 1:0.5-1, and the pyrazine chloride is 2, 6-dichloropyrazine, 3, 6-dichloropyrazine or 2, 4-dichloropyrimidine.
  7. 7. The method for preparing a nitrogen-doped porous carbon material with multiple nitrogen-rich units according to claim 1, wherein the carbonization treatment temperature is 600-800 o ℃ and the heating rate is 2-5 o C/min.
  8. 8. The method for preparing a nitrogen-doped porous carbon material with multiple nitrogen-rich units according to claim 1, wherein the mass ratio of the multiple nitrogen-rich porous organic polymer to the activator is 1:1-3.

Description

Preparation method and application of high-nitrogen-content nitrogen-doped porous carbon with multiple nitrogen-rich units Technical Field The invention belongs to the field of porous adsorbents, and particularly relates to a preparation method and application of nitrogen-doped porous carbon with multiple nitrogen-rich units and high nitrogen content. Background With excessive consumption of fossil fuels, significant emissions of CO 2 have resulted in serious environmental problems. The capture, utilization and sequestration of CO 2 is an important strategy for mitigating global warming threats. Among them, the capture of CO 2 is the most indispensable step. Amine-based solvent adsorbents are the most mature commercial CO 2 capture technology at present, but the amine washing process is not only energy-consuming, but also produces harmful byproducts. Therefore, there is a need to develop alternative CO 2 capture technologies to produce efficient CO 2 capture materials. At present, solid adsorbents that are expected to replace amine-based solvents have been developed more. The biomass porous carbon has the advantages of abundant raw materials, high specific surface area and pore volume, easy adjustment of pore structure, good thermal stability and contribution to capturing CO 2. However, the structure and pore size of these biomass porous carbons are unpredictable and the type of nitrogen content cannot be determined. For porous carbon adsorbents, the porous structure, pore volume, and surface characteristics all affect the ability to capture CO 2. The N atoms are introduced into the porous carbon, so that the adsorption capacity of the porous carbon can be effectively improved, the polarity and the alkalinity of the surface can be enhanced, and the reaction with CO 2 can be improved. Therefore, aiming at the problems that the nitrogen content, the CO 2 adsorption capacity, the selectivity and the like of the existing nitrogen-doped porous carbon are not high enough, the introduction mode of N atoms is changed on the basis of not affecting the comprehensive performance of the carbon material, an azide unit and a pyrazine unit are constructed, and the nitrogen-doped porous carbon with multiple nitrogen-rich units is constructed. The method has the advantages of realizing controllable N content, uniform distribution and improving the carbon residue rate, thereby further improving the CO 2 adsorption selectivity of the porous carbon. Disclosure of Invention Aiming at the technical problems in the prior art, the invention aims to provide a preparation method and application of nitrogen-doped porous carbon with multiple nitrogen-rich units and high nitrogen content. In order to achieve the aim and achieve the effect, the invention adopts the following technical scheme that pyrazine containing the bis-azido is taken as a crosslinking arm, the bis-azido and the bis-azido form a triazole structure through click chemical reaction of alkynyl and azido, and after crosslinking is achieved, the nitrogen-doped porous carbon with multiple nitrogen-rich units is constructed through activation and carbonization treatment. The N atoms can be used as a constructor of the framework, the N content is controllable and high, the distribution is more uniform, and the CO 2 adsorption selectivity of the porous carbon is further improved. The pore diameter of the carbon material is concentrated in the micropore-mesopore range by controlling the carbonization temperature and time, and the pore volume of the porous carbon is adjusted by changing the type and the proportion of the activating agent, so that the effective regulation and control of the micro-pore structure and the doping of nitrogen atoms are realized. The method specifically comprises the following steps: (1) Preparation of a bis-azido-containing pyrazine: dissolving potassium azide and pyrazine chloride in DMF, stirring at 60 ℃ for 24 hours, cooling to room temperature, pouring the reaction mixture into deionized water, filtering, washing, dissolving in chloroform, drying by magnesium sulfate, filtering, and evaporating the solvent to obtain the pyrazine containing the bisazide group. Further, the mass ratio of the potassium azide to the pyrazine chloride is 1:0.5-1. Further, the pyrazine chloride is 2, 6-dichloropyrazine, 3, 6-dichloropyrazine or 2, 4-dichloropyrimidine. (2) Preparation of a triazine containing a trisalkynyl group: (1) After evenly mixing cyanuric chloride, pdCl 2(PPh3)2, cuI and triethylamine, adding trimethylethynyl silicon in an N 2 atmosphere, stirring and reacting for 24 hours at 80 ℃, then adding dichloromethane for dilution, filtering by diatomite, extracting filtrate with CH 2Cl2 and water, washing with saturated NaCl, drying with anhydrous Na 2SO4, and spin-drying to obtain a compound 1; (2) Compound 1 was dissolved in methanol, then K 2CO3 was added, stirred at room temperature for 4 hours, and then dried by spinning, the organic phase was extr