Microporous metal organic framework material with pore channels containing oxygen-enriched groups as well as preparation and application of microporous metal organic framework material
By designing the microporous metal-organic framework material with oxygen-rich pore groups [Cd(PZDC)] in the pore, the problems of high adsorption enthalpy and large energy consumption of existing materials in CO2 capture are solved, excellent CO2 selectivity and adsorption capacity are achieved, and the stability and recyclability of the material are improved.
Patent Information
- Application Number
- CN202411637886.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-15
- Publication Date
- 2025-05-27
AI Technical Summary
The existing metal-organic framework materials have problems such as high adsorption enthalpy, large energy consumption and poor stability in CO2 capture, and it is difficult to achieve excellent adsorption performance, stability and recyclability at the same time.
A microporous metal-organic framework material with oxygen-rich pores [Cd(PZDC)] was designed, and the material was synthesized by solvothermal reaction. 2,3-pyrazine dicarboxylic acid was used as an organic ligand to form a hexa-coordinated three-dimensional frame structure with cadmium ions to form a one-dimensional rectangular pore of size.
The material exhibits excellent selectivity and adsorption capacity in CO2 capture, can effectively capture low concentrations of CO2, and has good stability and recyclability, reducing energy consumption.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of crystalline materials, and the technology relates to metal-organic coordination polymer materials, and is characterized by a metal-organic skeleton material whose pores contain abundant exposed oxygen groups, a preparation method and application research thereof. Background Art
[0002] Human dependence on fossil fuels has led to the emission of carbon dioxide (CO 2 ) excessive emissions. The continuous increase of carbon dioxide in the atmosphere has led to a series of serious climate problems. Although the amine solution absorption method is still the most mature post-combustion CO 2 Capture technology, but this technology has disadvantages such as high volatility, large-area corrosion of equipment and release of toxic pollutants, and due to its high adsorption enthalpy, it requires a lot of energy for regeneration. Compared with the high energy consumption of chemical absorption, porous adsorption materials have attracted widespread attention as an alternative. They usually have the advantages of fast adsorption kinetics, low regeneration cycle energy, no corrosion to equipment and no release of toxic pollutants. Common physical adsorbents include porous carbon, zeolites, ionic liquids, metal organic frameworks and porous organic polymers.
[0003] In particular, Metal-Organic Frameworks (MOFs), a three-dimensional network structure composed of metal ions and organic ligands connected by coordination bonds, is a type of organic-inorganic hybrid porous material with the characteristics of large specific surface area, high porosity, easy-to-adjust pore structure and performance. Due to these unique advantages, MOFs have been rapidly developed in many fields such as separation, sensing, and catalysis. Ideally, practical adsorbents for capturing trace amounts of carbon dioxide should not only have excellent adsorption properties (e.g., high adsorption capacity / selectivity, low adsorption enthalpy, and resistance to water vapor), but also have excellent stability and recyclability. However, the preparation of such MOFs remains a huge challenge because it is very difficult to achieve these characteristics simultaneously in MOFs. Therefore, CO can be effectively achieved through reasonable design and modification of pores. 2 Capture, which will promote the practical application of MOFs materials in the field of carbon capture. Summary of the invention
[0004] The purpose of the present invention is to provide a microporous metal organic framework material with oxygen-rich groups in its pores, a preparation method and an application thereof.
[0005] The metal-organic framework material with oxygen-rich groups in the pores of the present invention is characterized in that the chemical formula is [Cd(PZDC)], H 2 PZDC is an organic ligand 2,3-pyrazinedicarboxylic acid.
[0006] The metal-organic framework material has a three-dimensional framework structure. When the guest solvent molecule acetonitrile is included, from the perspective of the skeleton connection construction, the crystal structure of the metal-organic framework belongs to the orthorhombic system, the space group is Pnna, and the unit cell parameters are: α=β=γ=90°; after removing the guest solvent molecules, the crystal structure of the metal-organic framework belongs to the orthorhombic system, the space group is Imma, and the unit cell parameters are: α=β=γ=90°.
[0007] In this metal-organic framework, the Cd atom is hexacoordinated, surrounded by four oxygen atoms and two nitrogen atoms, which come from four different pyrazine diacid ligands.
[0008] In this metal-organic framework, the bond lengths of Cd-O bonds are and The bond length of Cd-N is Each pyrazine dicarboxylic acid ligand has two uncoordinated oxygen atoms exposed in the pore. The metal Cd atom and the ligand 2,3-pyrazine dicarboxylic acid form a chelate-coordinated pore with a size of The one-dimensional channel has a rectangular shape.
[0009] From a topological point of view, each 2,3-pyrazinedicarboxylic acid ligand can be regarded as a 4-connected node, while the hexacoordinated Cd can be regarded as a 4-connected vertex. These two types of structural units are alternately connected to form a (4, 4)-connected pts network.
[0010] The organic ligand is 2,3-pyrazinedicarboxylic acid (H 2 PZDC), i.e., two-headed pyrazine carboxylic acid ligand, has the following structural formula:
[0011]
[0012] The ligand comprises a pyrazine ring and two carboxylic acids; the angle between two adjacent carboxyl groups in the ligand is 60°, and the carboxyl group is directly connected to the pyrazine ring.
[0013] The method for synthesizing the metal-organic framework material of the present invention comprises the following steps:
[0014] Under sealed conditions, 2,3-pyrazinedicarboxylic acid (H 2 PZDC) and cadmium chloride (CdCl 2 ) or cadmium nitrate (Cd(NO 3 ) 2 ) in a mixed solution of N,N-dimethylformamide (DMF), acetonitrile and water, and the crystals of the metal-organic framework were obtained via a solvothermal reaction.
[0015] The organic ligand 2,3-pyrazinedicarboxylic acid (H 2 PZDC) and cadmium chloride (CdCl 2 ) or cadmium nitrate (Cd(NO 3 ) 2 ) is 1:(1-5), and every 0.3 mmol of cadmium chloride (CdCl 2 ) or cadmium nitrate (Cd(NO 3 ) 2 ) corresponds to 2mL-15mL of DMF, 1mL-10mL of acetonitrile, and 0mL-3mL of water. The temperature of the thermal reaction is 60°C-140°C, and the reaction time is 8-48 hours.
[0016] The MOF synthesized in the present invention belongs to a new type of microporous metal-organic framework. The metal-organic framework pores constructed in the present invention have oxygen-rich groups, which makes the MOF 2 It has potential applications in capture. BRIEF DESCRIPTION OF THE DRAWINGS
[0017] Figure 1 Diagram of the secondary building unit of the metal-organic framework, (a) the corresponding coordination environment diagram of cadmium, and (b) the corresponding ligand.
[0018] Figure 2 Schematic diagram of the three-dimensional structure (a) and topology (b) of the metal-organic framework.
[0019] Figure 3 The metal-organic framework material has a CO 2 (a) (corresponding to 25-40℃) and N 2 (b) Adsorption isotherm diagram. DETAILED DESCRIPTION
[0020] The present invention will be further described below in conjunction with examples, but the present invention is not limited to the following examples.
[0021] Embodiment 1:
[0022] Weigh the commercially available ligand H 2 PZDC (0.3 mmol) and CdCl 2 2.5H 2O (0.3mmol) was placed in a 20mL glass vial, and 8mL of DMF solution, 2mL of acetonitrile solution and 1mL of water were added. The vial was then sealed and placed in an ultrasonic instrument for ultrasonication at room temperature for 5 minutes. After sealing, the vial was placed in a 100°C oven for reaction for 12 hours. After the reaction was completed, the oven was turned off, and after cooling to room temperature, the solid particles obtained in the vial were collected by filtration, and then washed with DMF and acetonitrile (5mL×3) in turn. Colorless and transparent strip crystals [Cd(PZDC)(CH 3 CN)], (yield: 95%, based on H 2 PZDC ligand).
[0023] Embodiment 2:
[0024] Weigh the commercially available ligand H 2 PZDC (1.5 mmol) and CdCl 2 2.5H 2 O (1.5mmol) was placed in a 100mL glass bottle, 40mL of DMF solution, 10mL of acetonitrile solution and 3mL of water were added, and then the vial was sealed and placed in an ultrasonic instrument for ultrasonication at room temperature for 5 minutes. After sealing, the vial was placed in an oven at 80°C for reaction for 12 hours. After the reaction was completed, the oven was turned off, and after cooling to room temperature, the solid particles obtained in the vial were collected by filtration, and then washed with DMF and acetonitrile (5mL×3) in turn. Colorless and transparent strip crystals [Cd(PZDC)(CH 3 CN)], (yield: 90%, based on H 2 PZDC ligand).
[0025] Embodiment 3:
[0026] Weigh the commercially available ligand H 2 PZDC (2.0 mmol) and CdCl 2 2.5H 2 O (2.0mmoL) was placed in a 100mL round-bottom flask, and 40mL of DMF, 10mL of acetonitrile solution and 5mL of water were added. The flask was then sealed and placed in an ultrasonicator for ultrasonication at room temperature for 5 minutes. After sealing, the flask was placed in a 60°C oil bath and stirred for reaction for 6 hours. After the reaction was completed, the oil bath was turned off, and after cooling to room temperature, the solid powder obtained in the flask was collected by centrifugation, and then washed with DMF and acetonitrile (5mL×3) in turn. White powder crystals [Cd(PZDC)(CH 3 CN)], (yield: 90%, based on H 2 PZDC ligand).
[0027] The test results of the products obtained in the above embodiments are the same, as shown below:
[0028] (1) Determination of crystal structure:
[0029] Powders of appropriate size were selected and data were collected using a PANalytical X'Pert PRO high-resolution powder diffractometer at 200 K. Data were collected using Cu-Kα monochromated with a graphite monochromator. Target beam. Absorption correction of the data was done using SCALE3 ABSPACK software. The crystal structure was solved by direct method using SHELXTL-97 program. First, the coordinates of all non-hydrogen atoms were determined by difference function method and least square method, and the positions of hydrogen atoms were obtained by theoretical hydrogenation method, and then the crystal structure was refined using SHELXTL-97. See the structure diagram for details. Figure 2 The crystallographic data are shown in Table 1.
[0030] Table 1 Crystallographic data of metal organic framework materials
[0031]
[0032] Figure 1 The structural diagram shows that the inorganic node contained in the framework structure is mononuclear cadmium and the organic ligand is 2,3-pyrazinedicarboxylic acid.
[0033] Figure 2 The structural diagram shows the three-dimensional stacking diagram in the metal-organic framework.
[0034] (2)CO 2 and N 2 Adsorption
[0035] Figure 3 The adsorption isotherms of carbon dioxide and nitrogen and the simulated flue gas (CO 2 :N 2 =4:96) under the condition of penetration test. From the adsorption curve and penetration test, it can be seen that the material can selectively capture CO from low-concentration flue gas. 2 . Figure 3 The material of the present invention is tested by gas adsorption instrument in a constant temperature bath for CO 2 ( Figure 3 (a), 298K and 313K) and N 2 ( Figure 3 (a), adsorption isotherms at 298K and 313K and the selective capture of CO from low-concentration flue gas tested by penetrometer. 2 ( Figure 3 (b)) penetration test.
Claims
1. A microporous metal organic framework material having pores containing oxygen-rich groups, characterized in that: The chemical formula is [Cd(PZDC)], where H2PZDC is the organic ligand 2,3-pyrazinedicarboxylic acid.
2. A microporous metal organic framework material having pores containing oxygen-rich groups according to claim 1, characterized in that: The metal-organic framework material has a three-dimensional framework structure. When the guest solvent molecule acetonitrile is included, from the perspective of the skeleton connection construction, the crystal structure of the metal-organic framework belongs to the orthorhombic system, the space group is Pnna, and the unit cell parameters are: α=β=γ=90°; after removing the guest solvent molecules, the crystal structure of the metal-organic framework belongs to the orthorhombic system, the space group is Imma, and the unit cell parameters are: α=β=γ=90°.
3. A microporous metal organic framework material having pores containing oxygen-rich groups according to claim 1, characterized in that: In this metal-organic framework, the Cd atom is hexacoordinated, surrounded by four oxygen atoms and two nitrogen atoms, which come from four different pyrazine diacid ligands.
4. A microporous metal organic framework material having pores containing oxygen-rich groups according to claim 1, characterized in that: From a topological point of view, each porphyrin carboxylic acid ligand can be regarded as a 4-connected node, while the hexacoordinated Cd can be regarded as a 4-connected vertex. These two types of structural units are alternately connected to form a (4, 4)-connected pts network.
5. A microporous metal organic framework material having pores containing oxygen-rich groups according to claim 1, characterized in that: The organic ligand is 2,3-pyrazinedicarboxylic acid (H2PZDC), i.e., a two-headed pyrazine carboxylic acid ligand, and the structural formula is shown below: The ligand comprises a pyrazine ring and two carboxylic acids; the angle between two adjacent carboxyl groups in the ligand is 60°, and the carboxyl group is directly connected to the pyrazine ring.
6. The method for preparing a microporous metal organic framework material having pores containing oxygen-rich groups according to any one of claims 1 to 5, characterized in that: The following steps are involved: Under sealed conditions, 2,3-pyrazinedicarboxylic acid (H2PZDC) and cadmium chloride (CdCl2) or cadmium nitrate (Cd(NO3)2) are reacted in a mixed solution of N,N-dimethylformamide (DMF), acetonitrile and water via solvothermal reaction to obtain the crystals of the metal-organic framework.
7. The method according to claim 6, characterized in that The molar ratio of the organic ligand 2,3-pyrazinedicarboxylic acid (H2PZDC) to cadmium chloride (CdCl2) or cadmium nitrate (Cd(NO3)2) is 1:(1-5), and every 0.3 mmol of cadmium chloride (CdCl2) or cadmium nitrate (Cd(NO3)2) corresponds to 2 mL-15 mL of DMF, 1 mL-10 mL of acetonitrile, and 0 mL-3 mL of water. The temperature of the thermal reaction is 60°C-140°C, and the reaction time is 8-48 hours.
8. Use of the microporous metal organic framework material having pores containing oxygen-rich groups as claimed in any one of claims 1 to 5 in the selective capture of carbon dioxide.
9. The use according to claim 8 for selective capture of CO2 in N2 atmosphere.