Nickel-based metal organic framework material, preparation method thereof and application of nickel-based metal organic framework material in simultaneous capture of N2O and CO2

Abstract

The invention relates to the technical field of metal-organic coordination polymer crystalline materials, in particular to a nickel-based metal organic framework material, a preparation method thereof and application of the nickel-based metal organic framework material in capturing N2O and CO2 at the same time, the chemical molecular formula is C12H18N4NiO6, the used organic ligand is 1H-pyrazole-4-formic acid, structural transformation can occur after degassing, and the chemical molecular formula after transformation is C8H6N4NiO4. The nickel-based metal organic framework material has application potential in simultaneous capture of N2O and CO2.

Description

Technical Field

[0001] The present invention relates to the technical field of metal-organic coordination polymer crystalline materials, and in particular to a nickel-based metal organic framework material and a preparation method thereof and a method for simultaneously capturing N 2 O and CO 2 application. Background Art

[0002] Excessive greenhouse gas emissions have had a very serious impact on the global climate, such as sea level drop, pests and diseases, and land desertification. 2 It is the most important greenhouse gas, CH 4 , N 2 O, fluorinated gases are collectively referred to as non-CO2 greenhouse gases. Although their content is small, the greenhouse effect they produce is extremely high. 2 The greenhouse effect produced by O is CO 2 The tail gas emission of industrial synthesis of adipic acid is N 2 O is the largest industrial emission source, and its tail gas is mainly composed of N 2 O / N 2 / CO 2 / O 2 (48 / 44 / 4 / 4). At present, the main methods for treating the tail gas produced by the synthesis of adipic acid are thermal decomposition and catalytic decomposition. However, thermal decomposition technology consumes a lot of energy and produces additional CO. 2 Gas, the catalyst life of catalytic decomposition technology is short, the catalyst needs to be replaced frequently, and the cost is high. The adsorption separation method is relatively energy-saving and economical. Metal organic framework materials (MOFs) are a new type of crystalline porous functional material. It is a porous network skeleton structure material formed by metal / metal cluster nodes and organic ligands based on coordination bonds. Due to its diverse structures, adjustable sizes, large specific surface area and other characteristics, it has been used as a physical adsorbent in various adsorption and separation systems, such as ethane / ethylene, acetylene / ethylene to purify ethylene, propane / propylene, etc. MOFs have also made preliminary explorations in the purification and separation of non-CO2 greenhouse gases, such as: CH 4 / N 2 , N 2 O / N 2 , N 2 O / CO 2 , SF 6 / N 2 However, no one has yet studied how to capture both greenhouse gases in the same system. 2 O adsorption and CO in low pressure zone 2 The adsorption capacity is N 2 O / N 2 / CO2 / O 2 Capture N 2 O and CO 2 At present, no adsorbent has been found to meet the above two conditions at the same time. Summary of the invention

[0003] In view of the problems existing in the prior art, the present invention provides a nickel-based metal organic framework material and a preparation method thereof and a method for simultaneously capturing N 2 O and CO 2 application.

[0004] The present invention is achieved through the following technical solutions: A nickel-based metal organic framework material with a chemical formula of C 12 H 18 N 4 NiO 6 , the organic ligand used is 1H-pyrazole-4-carboxylic acid, the structure is as follows: ; The nickel-based metal organic framework material undergoes a structural transformation after degassing, and the chemical molecular formula after the transformation is C 8 H 6 N 4 NiO 4 .

[0005] Furthermore, before degassing, the nickel-based metal-organic framework material has a two-dimensional framework structure; after degassing, the nickel-based metal-organic framework material has a three-dimensional framework structure.

[0006] Furthermore, from the perspective of skeleton connection construction, the crystal structure of the nickel-based metal organic framework material before degassing belongs to the monoclinic system, and the space group is: P 2 1 / c The unit cell parameters are: a = 7.4193Å, b = 8.3916Å, c = 13.0641Å, α = 90°, β = 102.254°, γ = 90°; The crystal structure of the degassed nickel-based metal organic framework material belongs to the monoclinic system, and the space group is P21 / n, The unit cell parameters are: a=5.0836(7)Å, b=8.2916(11)Å, c=12.4737(15)Å, α =90°, β =91.158(13)°, γ =90°.

[0007] Furthermore, in the two-dimensional framework structure, the Ni atom is hexacoordinated with four oxygen atoms and two nitrogen atoms. The two nitrogen atoms come from two different 1H-pyrazole-4-carboxylic acid ligands, the two oxygen atoms come from the carboxyl groups of two different 1H-pyrazole-4-carboxylic acid ligands, and the remaining two oxygen atoms come from two ethanol molecules. In the two-dimensional framework structure, the Ni-O bond length between the Ni atom and the O atom on the carboxyl group of the ligand is 2.043Å, the Ni-O bond length between the Ni atom and the hydroxyl oxygen in ethanol is 2.099Å, and the Ni-N bond length between the Ni atom and the pyrazole nitrogen in the ligand is 2.068Å. One nitrogen atom of each 1H-pyrazole-4-carboxylic acid ligand is coordinated with one Ni atom, and one oxygen atom of a carboxyl group is coordinated with an adjacent Ni atom, that is, adjacent Ni atoms are connected via a bridging ligand.

[0008] In the two-dimensional framework structure, there are rhombus-shaped channels with a side length of 7.6Å, and coordinated ethanol guest molecules are distributed in the channels.

[0009] Furthermore, in the three-dimensional framework structure of the nickel-based metal-organic framework material after degassing, The Ni atom is hexacoordinated, coordinated by four oxygen atoms and two nitrogen atoms. The four oxygen atoms come from the carboxyl groups of four different ligands, and the two nitrogen atoms come from the pyrazole nitrogen in two ligands. The Ni-O bond lengths between the Ni atom and the carboxyl oxygen in the ligand are 2.166Å and 2.080Å, respectively, and the Ni-N bond length between the Ni atom and the pyrazole nitrogen in the ligand is 2.068Å. The two oxygen atoms of the carboxyl group of each 1H-pyrazole-4-carboxylic acid ligand are coordinated to two Ni atoms, and the nitrogen atom is coordinated to another Ni atom; Adjacent nickel atoms are bridged by two oxygen atoms of the carboxyl groups of two 1H-pyrazole-4-carboxylic acid ligands to form a one-dimensional chain structural unit, and the one-dimensional chains form a three-dimensional framework structure through the 1H-pyrazole-4-carboxylic acid ligands. The three-dimensional framework structure has a diamond-shaped channel with a side length of 7.8Å.

[0010] The present invention also provides a method for preparing the nickel-based metal organic framework material, comprising the following steps: Under sealed conditions, 1H-pyrazole-4-carboxylic acid and nickel nitrate hexahydrate were added to ethanol, and the crystal C of nickel-based metal organic framework material was obtained through solvothermal reaction. 12 H 18 N 4 NiO 6 .

[0011] Furthermore, the molar ratio of 1H-pyrazole-4-carboxylic acid to nickel nitrate hexahydrate is 1:(1-2), each 0.06 mmol of 1H-pyrazole-4-carboxylic acid corresponds to 1 mL-3 mL of ethanol, the temperature of the solvothermal reaction is 60-80° C., and the reaction time is 8-48 hours.

[0012] Further, the crystal C of the nickel-based metal organic framework material 12 H 4 N 4 NiO 4 Soak in dichloromethane for washing, perform solvent exchange, and then vacuum degas to obtain the converted crystalline material C 8 H 6 N 4 NiO 4 .

[0013] The present invention also provides the nickel-based metal organic framework material for simultaneously capturing N 2 O and CO 2 Application in.

[0014] Beneficial technical effects of the present invention: The present invention utilizes the shortest pyrazolecarboxylic acid organic ligand 1H-pyrazole-4-carboxylic acid to construct two crystalline materials. The crystalline material without degassing is a two-dimensional framework structure, and the crystalline material after degassing is a three-dimensional framework structure. The three-dimensional framework structure has a larger cubic cage and can be used for gas adsorption and separation.

[0015] The nickel-based metal organic framework material obtained by the present invention has a high adsorption capacity for nitrous oxide and carbon dioxide, and the framework has a strong interaction with the two molecules, among which the adsorption capacity for CO in the low pressure region is relatively high. 2 With a high adsorption capacity, N 2 O and CO 2 , so it can be used for the treatment of tail gas from industrial synthesis of adipic acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a coordination environment diagram of nickel in the two-dimensional framework structure of the nickel-based metal organic framework material obtained in Examples 1-3.

[0017] Figure 2 This is a diagram of the coordination environment of nickel in the three-dimensional framework structure of the nickel-based metal organic framework material obtained in Examples 1-3 after degassing.

[0018] Figure 3 This is a two-dimensional framework structure diagram of the nickel-based metal organic framework material obtained in Examples 1-3.

[0019] Figure 4This is a diagram of the three-dimensional framework structure of the nickel-based metal organic framework material obtained in Example 1-3 after degassing.

[0020] Figure 5 This is the adsorption isotherm of nickel-based metal-organic framework materials for nitrous oxide, carbon dioxide and nitrogen.

[0021] Figure 6 This is the adsorption isotherm of nickel-based metal-organic framework materials for acetylene, ethylene and ethane.

[0022] Figure 7 Ni-based metal-organic frameworks for CO 2 / N 2 Dynamic penetration curve of (96 / 4).

[0023] Figure 8 Ni-based metal organic framework materials for N 2 O / N 2 (50 / 50) dynamic penetration curve diagram.

[0024] Fig. 9 Ni-based metal organic framework materials for N 2 O / N 2 / CO 2 / O 2 Dynamic penetration curve of (48 / 44 / 4 / 4).

[0025] Fig.10 The Ni-based metal organic framework material has been subjected to five cycles of N 2 O / N 2 / CO 2 / O 2 Dynamic penetration curve of (48 / 44 / 4 / 4).

[0026] Fig.11 Under the condition of RH=40%, the Ni-based metal organic framework material has a 2 O / N 2 / CO 2 / O 2 Dynamic penetration curve of (48 / 44 / 4 / 4).

[0027] Fig.12 Figure 2 shows the Ni-based metal organic framework material for N after 5 cycles under RH = 40%. 2 O / N 2 / CO 2 / O 2 Dynamic penetration curve of (48 / 44 / 4 / 4).

[0028] Fig.13 Ni-based metal organic frameworks and N 2 O mechanism of action diagram.

[0029] Fig.14 For nickel-based metal-organic frameworks and CO 2 Diagram of the mechanism of action. DETAILED DESCRIPTION

[0030] The present invention will be further described below in conjunction with examples, but the present invention is not limited to the following examples.

[0031] Example 1 Weigh the ligand 1H-pyrazole-4-carboxylic acid (0.06 mmol) and Ni(NO 3 ) 2 6H 2 O (0.12mmoL) was placed in a 4mL glass vial, 3mL of ethanol was 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 80℃ oven for reaction for 8 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 ethanol (5mL×3) in turn, and then soaked in dichloromethane. Light green square crystals (C 12 H 18 N 4 NiO 6 ), (yield: 64%, based on ligand).

[0032] Example 2 Weigh the ligand 1H-pyrazole-4-carboxylic acid (0.06 mmol) and Ni(NO 3 ) 2 6H 2 O (0.09mmoL) was placed in a 4mL glass vial, 2mL of ethanol was 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 a 60°C oven for reaction for 48 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 ethanol (5mL×3) in turn, and then soaked in dichloromethane. Light green square crystals (C 12 H 18 N 4 NiO 6 ), (yield: 70%, based on ligand).

[0033] Example 3 Weigh the ligand 1H-pyrazole-4-carboxylic acid (0.06 mmol) and Ni(NO 3 ) 2 6H 2O (0.06 mmol / L) was placed in a 4 mL glass vial, 1 mL of ethanol was added, and then the vial was sealed and placed in an ultrasonicator for 5 minutes at room temperature. After sealing, the vial was placed in a 70 °C oven for reaction for 24 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 ethanol (5 mL×3) in turn, and then soaked in dichloromethane. Light green square crystals (C 12 H 18 N 4 NiO 6 ), (yield: 59%, based on ligand).

[0034] The test results of the products obtained in the above examples are the same. The products obtained in the above examples are soaked in dichloromethane, solvent exchange is performed, and then vacuum degassing is performed to obtain the converted crystal material C. 8 H 6 N 4 NiO 4 .

[0035] (1) Determination of crystal structure: Select crystals of appropriate size and collect data at room temperature using an Agilent Technologies SuperNova X-ray single crystal diffractometer. Data collection uses a Cu-Kα (λ=1.54178Å) target beam monochromated by a graphite monochromator. The crystal structure was solved by the direct method using the Olex2 program. The crystallographic data obtained before and after degassing are shown in Tables 1 and 2.

[0036] Table 1 Crystallographic data of metal organic framework materials (before degassing) Table 2 Crystallographic data of metal organic framework materials (after degassing) The crystal structure obtained in Example 1-3 is shown in FIG. Figure 1 and 3 As shown, it is shown that the inorganic nodes contained in the two-dimensional framework structure are mononuclear nickel, the Ni atom is hexacoordinated, and is coordinated with four oxygen atoms and two nitrogen atoms. The coordinated two nitrogen atoms come from two different 1H-pyrazole-4-carboxylic acid ligands, the two oxygen atoms come from the carboxyl groups of two different 1H-pyrazole-4-carboxylic acid ligands, and the remaining two oxygen atoms come from two ethanol molecules. One nitrogen atom of each 1H-pyrazole-4-carboxylic acid ligand is coordinated with one Ni atom, and one oxygen atom of the carboxyl group is coordinated with the adjacent Ni atom, that is, the adjacent Ni atoms are connected by a bridging ligand. In the two-dimensional framework structure, there is a rhombus channel with a side length of 7.6Å, and the coordinated ethanol guest molecules are distributed in the channel.

[0037] The crystal structure after degassing is as follows Figure 2 and Figure 4 As shown, it indicates that: in the three-dimensional framework structure of the nickel-based metal-organic framework material after degassing, the Ni atom is hexacoordinated, coordinated with four oxygen atoms and two nitrogen atoms, the coordinated four oxygen atoms come from the carboxyl groups of four different ligands, the coordinated two nitrogen atoms come from the pyrazole nitrogen in two ligands, the two oxygen atoms of the carboxyl group of each 1H-pyrazole-4-carboxylic acid ligand are coordinated with two Ni atoms respectively, and the nitrogen atom is coordinated with another Ni atom; adjacent nickel atoms are bridged by the two oxygen atoms of the carboxyl groups of two 1H-pyrazole-4-carboxylic acid ligands to form a one-dimensional chain structural unit, and the one-dimensional chains form a three-dimensional framework structure through the 1H-pyrazole-4-carboxylic acid ligands; in the three-dimensional framework structure, there is a rhombus channel with a side length of 7.8Å.

[0038] Example 4 The degassed metal organic framework material was tested for the adsorption isotherms of nitrous oxide, carbon dioxide, nitrogen, acetylene, ethylene, and ethane. The results are as follows Figure 5 and Figure 6 As shown in the figure, it is found that the material is N 2 O and CO 2 The maximum adsorption capacity is 78.8 cm g -1 , 74.3cmg -1 This indicates that the material has a high adsorption capacity for both gases, and both gases have a strong interaction with the framework, which is manifested in a very steep adsorption trend in the low-pressure area. 2 O and CO 2 Has application potential.

[0039] Example 5 Penetration Test The degassed crystalline material samples were filled into quartz glass columns and heated using CO 2 / N 2 (4 / 96), N 2 O / N 2 (50 / 50) penetration test, the results are as follows Figure 7 and Figure 8 As shown, it shows that the material has a 2 / N 2 , N 2 O / N 2 Excellent separation effect.

[0040] Example 6 Exhaust gas simulation experiment The degassed crystalline material sample was filled into a quartz glass column, and the mixed gas was N 2 O / N 2 / CO 2 / O 2 (48 / 44 / 4 / 4) conducted a penetration test and the results were as follows Fig. 9 As shown, it shows that under this composition, the material can capture N 2 O and CO 2 And after five rounds of testing, the separation performance did not decrease. Fig.10 .

[0041] In order to simulate the real environment of exhaust gas more realistically, the N 2 O / N 2 / CO 2 / O 2 (48 / 44 / 4 / 4) The test results of the four-component dynamic separation performance are as follows: Fig.11 , under RH=40%, the material can still capture N 2 O and CO 2 And after five rounds of testing, its separation performance can still be maintained. Fig.12 .

[0042] Example 7 Loading single crystal test and mechanism analysis In order to analyze the adsorption mechanism more clearly, we used single crystal X-ray diffraction to characterize the adsorption mechanism of N 2 O and CO 2 The single crystal was tested, and the analysis showed that the frame and N 2 O has multiple CH···N and CH···O interactions with CO 2 There are multiple CH···O interactions. And the appropriate pore size is important for N 2 O and CO 2 A strong confinement effect is produced. Fig.13 , Fig.14 .

Claims

1. A nickel-based metal organic framework material, characterized in that: The chemical formula is C 12 H 18 N4NiO6, the organic ligand used is 1H-pyrazole-4-carboxylic acid, the structure is as follows: ； The nickel-based metal organic framework material undergoes a structural transformation after degassing, and the chemical molecular formula after the transformation is C8H6N4NiO4.

2. The nickel-based metal organic framework material according to claim 1, characterized in that: Before degassing, the nickel-based metal-organic framework material has a two-dimensional framework structure; after degassing, the nickel-based metal-organic framework material has a three-dimensional framework structure.

3. The nickel-based metal organic framework material according to claim 1, characterized in that: From the perspective of skeleton connection construction, the crystal structure of the nickel-based metal organic framework material before degassing belongs to the monoclinic system, and the space group is: P twenty one / c The unit cell parameters are: a = 7.4193Å, b = 8.3916Å, c = 13.0641Å, α = 90°, β = 102.254°, γ = 90°; The crystal structure of the degassed nickel-based metal organic framework material belongs to the monoclinic system, and the space group is P21 / n, The unit cell parameters are: a=5.0836(7)Å, b=8.2916(11)Å, c=12.4737(15)Å, α =90°, β =91.158(13)°, γ =90°.

4. The nickel-based metal organic framework material according to claim 2, characterized in that: In the two-dimensional framework structure, the Ni atom is hexacoordinated with four oxygen atoms and two nitrogen atoms. The two nitrogen atoms come from two different 1H-pyrazole-4-carboxylic acid ligands, the two oxygen atoms come from the carboxyl groups of two different 1H-pyrazole-4-carboxylic acid ligands, and the remaining two oxygen atoms come from two ethanol molecules. In the two-dimensional framework structure, the Ni-O bond length between the Ni atom and the O atom on the carboxyl group of the ligand is 2.043Å, the Ni-O bond length between the Ni atom and the hydroxyl oxygen in ethanol is 2.099Å, and the Ni-N bond length between the Ni atom and the pyrazole nitrogen in the ligand is 2.068Å. One nitrogen atom of each 1H-pyrazole-4-carboxylic acid ligand is coordinated with one Ni atom, and one oxygen atom of the carboxyl group is coordinated with an adjacent Ni atom, that is, adjacent Ni atoms are connected via a bridging ligand; In the two-dimensional framework structure, there are rhombus-shaped channels with a side length of 7.6Å, and coordinated ethanol guest molecules are distributed in the channels.

5. The nickel-based metal organic framework material according to claim 2, characterized in that: In the three-dimensional framework structure of the degassed nickel-based metal organic framework material, the Ni atom is hexacoordinated, coordinated with four oxygen atoms and two nitrogen atoms. The four oxygen atoms are from the carboxyl groups of four different ligands, and the two nitrogen atoms are from the pyrazole nitrogen in two ligands. The Ni-O bond lengths of the Ni atom and the carboxyl oxygen in the ligand are 2.166Å and 2.080Å, respectively, and the Ni-N bond length of the Ni atom and the pyrazole nitrogen in the ligand is 2.068Å. The two oxygen atoms of the carboxyl group of each 1H-pyrazole-4-carboxylic acid ligand are coordinated to two Ni atoms, and the nitrogen atom is coordinated to another Ni atom; Adjacent nickel atoms are bridged by two oxygen atoms of the carboxyl groups of two 1H-pyrazole-4-carboxylic acid ligands to form a one-dimensional chain structural unit, and the one-dimensional chains form a three-dimensional framework structure through the 1H-pyrazole-4-carboxylic acid ligands. The three-dimensional framework structure has a diamond-shaped channel with a side length of 7.8Å.

6. A method for preparing the nickel-based metal organic framework material according to any one of claims 1 to 5, characterized in that: The following steps are involved: Under sealed conditions, 1H-pyrazole-4-carboxylic acid and nickel nitrate hexahydrate were added to ethanol, and the crystal C of nickel-based metal organic framework material was obtained through solvothermal reaction. 12 H 18 N4NiO6.

7. The method for preparing a nickel-based metal organic framework material according to claim 6, characterized in that: The molar ratio of 1H-pyrazole-4-carboxylic acid to nickel nitrate hexahydrate is 1:(1-2), each 0.06 mmol of 1H-pyrazole-4-carboxylic acid corresponds to 1 mL-3 mL of ethanol, the temperature of the solvent thermal reaction is 60-80° C., and the reaction time is 8-48 hours.

8. The method for preparing a nickel-based metal organic framework material according to claim 6, characterized in that: The nickel-based metal organic framework material crystal C 12 The H4N4NiO4 is immersed in dichloromethane for washing, solvent exchange is performed, and then vacuum degassing is performed to obtain the converted crystalline material C8H6N4NiO4.

9. Use of the nickel-based metal organic framework material as claimed in any one of claims 1 to 5 in the simultaneous capture of N2O and CO2.

Images