A zeolitic imidazolate framework material, its preparation method and application

Abstract

The application discloses a zeolitic imidazolate framework material, a preparation method and application thereof. The preparation method of the zeolitic imidazolate framework material comprises the following steps: a mixture of a zinc salt, a triazole ligand, an imidazole ligand and a solvent is heated to react, and a series of crystalline porous materials can be prepared. The application provides a scheme for designing more ternary ring structures in ZIF, and the zeolitic imidazolate framework material prepared by the application has lower skeleton density, good chemical stability and hydrophobicity, and excellent gas (such as CO2) adsorption capacity, so that flue gas carbon capture performance under high humidity can be realized.

Description

TECHNICAL FIELD

[0001] The present application relates to a zeolitic imidazolate framework material, a preparation method and application thereof. BACKGROUND

[0002] ZIF is a porous crystalline material with a zeolite-like structure. The chemical and thermal stability of ZIF makes it have many uses, such as selective capture of CO2.

[0003] In ZIF, transition metals such as Zn / Co replace tetrahedral atoms such as Si in zeolites, and since the included angle of two metal centers bridged by imidazole ligands is usually 145 degrees, it is very consistent with the Si-O-Si bond angle in zeolites, so it is used to replace the Si-O-Si bond angle therein. In addition, more three-membered rings in ZIF make it have a lower framework density, so it is committed to building more three-membered rings in ZIF.

[0004] Although there are currently hundreds of ZIFs reported, the principle of building three-membered rings in ZIF is not perfect, and only some specific conditions can produce three-membered rings composed of three imidazole ligands, and the determination of the synthesis conditions of multi-component mixed MOF is more complex. For example, ZIF-95, ZIF-100, etc. They are all three-membered rings constructed by three imidazole ligands. Since the included angle of the imidazole ligand is 135-145 degrees, the three-membered ring tension is too large and unstable, so this kind of three-membered ring structure rarely appears. Therefore, it is necessary to find a scheme to design more three-membered ring structures in ZIF. SUMMARY

[0005] In order to overcome the above defects in the prior art, the present application provides a zeolitic imidazolate framework material, a preparation method and application thereof. The present application relieves the three-membered ring tension in ZIF by adding a triazole ligand, so that the three-membered ring can be stably built, thereby providing a scheme to design more three-membered ring structures in ZIF, and the zeolitic imidazolate framework material prepared by the present application has a lower framework density, good chemical stability and hydrophobicity, and excellent gas (such as CO2) adsorption capacity, so that the flue gas carbon capture performance under high humidity can be realized.

[0006] The present application provides a preparation method of a zeolitic imidazolate framework material, which comprises the following steps: heating a mixture of a zinc salt, a triazole ligand, an imidazole ligand and a solvent, and then reacting.

[0007] In some embodiments, the triazole ligand can be a compound represented by formula (I),

[0008]

[0009] each R1is independently H, halogen (e.g., Cl or Br), amino, nitro, or C 1-4 alkyl (e.g., methyl); m is 0, 1, 2, 3, or 4 (e.g., 0, 1, or 2).

[0010] In some embodiments, the triazole ligand can be For example,

[0011] In some embodiments, the imidazole ligand can be a compound represented by formula (II),

[0012]

[0013] each R2is independently H, halogen (e.g., Cl or Br), amino, nitro, or C 1-4 alkyl (e.g., methyl); n is 0, 1, 2, 3, or 4 (e.g., 0, 1, or 2).

[0014] In some embodiments, the imidazole ligand can be

[0015] In some embodiments, the zinc salt can be zinc nitrate, preferably zinc nitrate hexahydrate.

[0016] In some embodiments, the solvent can be one or more of an amide solvent, an alcohol solvent, and a halogenated alkane solvent. The amide solvent can be DMF. The alcohol solvent can be isobutyl alcohol. The halogenated alkane solvent can be dichloromethane.

[0017] In some embodiments, the solvent can be a mixed solvent of an amide solvent and an alcohol solvent, and the volume ratio of the amide solvent to the alcohol solvent can be 1: (2-5), for example, 1:4.

[0018] In some embodiments, the solvent can be a mixed solvent of an amide solvent and a halogenated alkane solvent, and the volume ratio of the amide solvent to the halogenated alkane solvent can be 1: (2-5), for example, 1:4.

[0019] In some embodiments, the molar ratio of the triazole ligand to the imidazole ligand can be 4:6-9:1, for example, 2:1.

[0020] In some embodiments, the molar ratio of the zinc salt to the triazole ligand can be 1: (1-2), for example, 1:2.

[0021] In some embodiments, the amount of the solvent can not be specifically limited as long as it does not affect the reaction.

[0022] In some embodiments, the molar volume ratio of the triazole ligand to the solvent can be 0.035-0.65 mol / L, preferably 0.04-0.4 mol / L, and more preferably 0.1-0.12 mol / L.

[0023] In some embodiments, the molar volume ratio of the imidazole ligand to the solvent can be 0.025-0.25 mol / L, preferably 0.05-0.06 mol / L.

[0024] In some embodiments, the molar volume ratio of the zinc salt to the solvent can be 0.035-0.35 mol / L, preferably 0.05-0.06 mol / L.

[0025] In some embodiments, the heating reaction can be performed in an oven. The temperature of the heating reaction can be 80-120℃, preferably 80-100℃, and more preferably 80-90℃.

[0026] In some embodiments, the time of the heating reaction can not be specifically limited, and is preferably 24-96 hours, for example, 24, 48, 72, or 96 hours.

[0027] In some embodiments, the heating reaction is performed in the presence of a base. The base can be an organic amine, for example, tetra-n-butylammonium hydroxide.

[0028] The present application provides a zeolitic imidazolate framework material prepared by the preparation method as described above.

[0029] In some embodiments, the framework structure of the zeolitic imidazolate framework material can be composed of triazole ligand-based connecting units and imidazole ligand-based connecting units, and the molar ratio of the triazole ligand-based connecting units to the imidazole ligand-based connecting units is preferably (3-5):1.

[0030] In some embodiments, the zeolitic imidazolate framework material can be a prismatic crystal with a space group of P212121. The prismatic crystal can be about 0.12 x 0.10 x 0.013 mm 3 .

[0031] In some embodiments, the zeolitic imidazolate framework material can have an NPO topology.

[0032] In some embodiments, the zeolitic imidazolate framework material can comprise 3-12 membered ring channels.

[0033] The present application provides a use of the zeolitic imidazolate framework material as described above in flue gas carbon capture.

[0034] On the basis of common general knowledge in the art, the above-mentioned preferred conditions can be combined arbitrarily, thereby obtaining various preferred examples of the present application.

[0035] The reagents and raw materials used in the present application are commercially available.

[0036] The positive progress effect of the present application is that the present application provides a scheme for designing more three-membered ring structures in ZIFs, and the zeolitic imidazolate framework material prepared by the present application has a lower framework density, good chemical stability and hydrophobicity, and excellent gas (such as CO2) adsorption capacity, thereby realizing the flue gas carbon capture performance under high humidity. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 X-ray powder diffraction patterns of ZIF-1001 to ZIF-1006 prepared for Examples 1 to 6;

[0038] Figure 2 Structural schematic diagram of ZIF-1001 prepared for Example 1;

[0039] Figure 3 Scanning electron microscope images of ZIF-1001 to ZIF-1006 prepared for Examples 1 to 6;

[0040] Figure 4 Infrared spectrograms of ZIF-1001 to ZIF-1004 prepared for Examples 1 to 4;

[0041] Figure 5 CO2 and N2 adsorption isotherm graphs of ZIF-1001 to ZIF-1004 prepared for Examples 1 to 4 at three temperatures;

[0042] Figure 6 Schematic diagram of a gas separation performance testing device in Example 7;

[0043] Figure 7 CO2 and C2H6 adsorption separation curves of ZIF-1001 to ZIF-1004 prepared for Examples 1 to 4 at room temperature;

[0044] Figure 8 CO2 and N2 adsorption separation curves of ZIF-1001 to ZIF-1004 prepared for Examples 1 to 4 at room temperature;

[0045] Figure 9 Methanol and H2O vapor adsorption curves of ZIF-1001 to ZIF-1004 prepared for Examples 1 to 4 at 25℃;

[0046] Figure 10Pore size distribution plots of the materials ZIF-1001 to ZIF-1004 prepared for Examples 1 to 4 were calculated from the adsorption isotherms of CO2 at 273 K. DETAILED DESCRIPTION

[0047] The application is further illustrated by the following examples without thereby limiting the application to the examples described. The experimental methods in the following examples, for which no specific conditions are indicated, are carried out according to the usual methods and conditions, or according to the instructions of the commercial suppliers.

[0048] Examples 1 to 6: Preparation of imidazolate framework materials ZIF-1001 to ZIF-1006

[0049] Table 1 : Imidazolate ligands for ZIF-1001 to ZIF-1006

[0050]

[0051] ZIF-1001 :

[0052] Zn(NO3)2-6H2O (223.1 mg, 0.75 mmol), benzotriazole (178.7 mg, 1.50 mmol), benzimidazole (88.61 mg, 0.75 mmol) were mixed in a 20 ml vial and 15 ml DMF were added. The reaction was placed in a 100 °C oven for 2 days to yield a white solid.

[0053] ZIF-1002:

[0054] Zn(NO3)2-6H2O (223.1 mg, 0.75 mmol), benzotriazole (178.7 mg, 1.50 mmol), 5-methylbenzimidazole (99.12 mg, 0.75 mmol) were mixed in a 20 ml vial and 15 ml DMF were added. The reaction was placed in a 100 °C oven for 2 days to yield a white solid.

[0055] ZIF-1003:

[0056] Zn(NO3)2-6H2O (223.1 mg, 0.75 mmol), benzotriazole (178.7 mg, 1.50 mmol), 5-bromobenzimidazole (144.77 mg, 0.75 mmol) were mixed in a 20 ml vial and 15 ml DMF were added. The reaction was placed in a 100 °C oven for 2 days to yield a yellow solid.

[0057] ZIF-1004:

[0058] Zn(N03)2-6H20 (223.1 mg, 0.75 mmol), benzotriazole (178.7 mg, 1.50 mmol), 5- chlorobenzimidazole (114.44 mg, 0.75 mmol) were mixed in a 20 ml vial, and 15 ml DMF was added. The reaction was put in a 100 °C oven for 2 days to give a white solid.

[0059] ZIF-1005:

[0060] Zn(N03)2-6H20 (223.1 mg, 0.75 mmol), benzotriazole (178.7 mg, 1.50 mmol), 5- chlorobenzimidazole (114.44 mg, 0.75 mmol) were mixed in a 20 ml vial, and 15 ml DMF was added. The reaction was put in a 100 °C oven for 2 days to give a white solid.

[0061] ZIF-1006:

[0062] Zn(N03)2-6H20 (223.1 mg, 0.75 mmol), benzotriazole (178.7 mg, 1.50 mmol), 5- chlorobenzimidazole (114.44 mg, 0.75 mmol) were mixed in a 20 ml vial, and 15 ml DMF was added. The reaction was put in a 100 °C oven for 2 days to give a white solid.

[0063] Example 7: Structure characterization and performance test of imidazole framework materials:

[0064] 1. X-ray diffraction

[0065] 1a. X-ray powder diffraction

[0066] X-ray powder diffraction (PXRD) data were collected on a Bruker D8 powder X-ray diffractometer in Germany, using Cu target Ka radiation with a working current of 40 mA, a working voltage of 40 kV, and a scanning range of 5-30° at a scanning speed of 2° / min. The standard powder diffraction pattern was simulated from single crystal data by Mercury software of Cambridge company.

[0067] The X-ray powder diffraction patterns of ZIF-1001-ZIF-1006 prepared in Examples 1-6 are shown in Figure 1 .

[0068] 1b. X-ray single crystal diffraction

[0069] Single-crystal X-ray diffraction data were collected at the Shanghai Synchrotron Radiation Facility BL17B beamline (15 KeV: ) equipped with a marXperts MX300 CCD area detector. The data were reduced and corrected using the HKL3000 software, and no absorption correction and decay correction were applied. The single-crystal structure was solved by direct methods using the Olex2 software, and further refined by difference Fourier synthesis to locate all non-hydrogen atoms. All non-hydrogen atoms in the structure were refined anisotropically, hydrogen atoms were restrained to be rigid and refined isotropically, and all aromatic rings were restrained to be rigid. The occupancy of disordered structures was refined as a free parameter.

[0070] A schematic view of the structure of ZIF-1001 prepared in Example 1 is shown in Figure 2 .

[0071] 2. Scanning Electron Microscopy

[0072] The sample morphology was observed using a scanning electron microscope (SEM). The experiment was performed on a JEOL JSM 7800 Prime instrument. Acceleration voltage 1 kV, working distance 6.1 mm.

[0073] Scanning electron micrographs of ZIF-1001-ZIF-1006 prepared in Examples 1-6 are shown in Figure 3 .

[0074] 3. Infrared Absorption

[0075] Fourier-transform infrared (FT-IR) spectra were recorded on a PerkinElmer FT-IR spectrometer equipped with a single-bounce diamond ATR module, with a scan wavelength range of 4000-500 cm -1 , with a step size of 4 cm -1 .

[0076] FT-IR spectra of ZIF-1001-ZIF-1004 prepared in Examples 1-4 are shown in Figure 4 .

[0077] 4. Gas Adsorption and Separation Performance

[0078] The ZIF-1001-ZIF-1004 powders prepared in Examples 1-4 were washed with DMF for 2 days and exchanged with methanol for 5 days, three times a day. The gas adsorption and separation performance of the samples was tested after heating and degassing activation.

[0079] 4a. Gas Adsorption Performance

[0080] The well-exchanged powder sample was transferred into a 9 mm adsorption sample tube, which was connected to a Quantachrome Flotec vacuum degassing station. The sample was first evacuated at room temperature for 2-3 h until the vacuum degree was reduced to < 500 mTorr, and then heated at a heating rate of 1 °C min -1 -1 to 120 °C overnight. The final vacuum degree should be maintained at < 10 mTorr, and the final framework with completely removed guest molecules was obtained.

[0081] The fully activated sample was transferred to a Belsorp Max II high-throughput specific surface area analyzer for testing the CO2 (273, 283, 298 K), N2 (298 K) adsorption isotherms. The sample testing temperature was controlled by a German Optimal F12-E0 heating-cooling circulating water bath, with a temperature control stability of ± 0.02 °C.

[0082] The CO2 and N2 adsorption isotherm graphs of ZIF-1001 to ZIF-1004 prepared in Examples 1 to 4 at three temperatures are shown in Figure 5 .

[0083] 4b, Gas separation performance

[0084] Before each breakthrough curve test, the sample was activated, and the sample column was loaded through a 6 mm O-ring and an adapter into a Quantachrome Flotec degassing station for heating and degassing at 100 °C. After about 2 h, the pressure was stabilized at 10 mTorr.

[0085] In order to avoid the contact of the sample with air as much as possible, the activated sample was transferred to the breakthrough equipment under the condition of passing He (10 mL min -1 ). At this time, the four-way valve was connected to He and the sample column, and after one hour, the four-way valve was turned to the working gas direction for breakthrough experiment.

[0086] In this experiment, the multi-component gas breakthrough curve was obtained by the self-built gas component control device in the laboratory and the commercial GC-9860 (TCD detector) linkage test, as shown in Figure 6 . When testing the separation performance of the sample column, the working gas passed through the gas pressure reducing valve and flowed into the mass flow controller (Alicat mass flow controllers, MFCs) after mixing at a certain speed (CO2 0.15 mL min -1 + N2 0.85 mL min -1 ). The four-way valve was connected to the test gas and the sample column (15 cm long, 0.42 cm in diameter, and 2.1 cm 3The sample column is connected to the gas chromatograph (GC-9860, which uses an Al2O3 packed column to separate the incoming CO2 and N2), and the absolute contents of CO2 and N2 are detected by a TCD detector.

[0087] Add 0.85 mL min of N2 to the working gas. -1 ) through an ultrapure water bubbler and dry CO2 (0.15 mL min) -1 A working gas with 85% humidity was prepared by mixing. Before testing for the 85% humidity breakthrough, the working gas was directly passed through a GC and hygrometer to analyze its composition, ensuring that the ultrapure water was saturated with N2 and that the working gas humidity reached 85% RH. During each test, the pre-column and post-column pressures were monitored to ensure a pressure difference of <1 psi and that the pressure remained essentially constant throughout the test, thus eliminating false separation performance caused by pressure increases.

[0088] The sample packing amounts in the separation column were 0.8185 g ZIF-1001, 0.4199 g ZIF-1002, 1.1671 g ZIF-1003, or 1.1387 g ZIF-1004, all in powder form. Breakthrough of the empty sample column was tested before formal sample analysis to obtain the system's dead time and standard effluent concentration. Subsequent sample breakthrough curves were adjusted to account for this dead time.

[0089] The adsorption and separation curves of CO2 and C2H6 of ZIF-1001 to ZIF-1004 prepared in Examples 1 to 4 at room temperature are shown below. Figure 7 As shown, the adsorption and separation curves of CO2 and N2 at room temperature are as follows: Figure 8 As shown.

[0090] 5. Adsorption performance of methanol and H2O vapor

[0091] The fully activated 100-200 mg sample was transferred to a Belserp Max II high-throughput surface area analyzer (Japan) to test the MeOH (298 K) and H2O (298 K) vapor adsorption performance of the sample. Both MeOH and deionized water underwent at least three cycles of liquid nitrogen freeze-drying-dissolution before testing to remove air dissolved in the solvent.

[0092] The adsorption performance of ZIF-1001 to ZIF-1004 prepared in Examples 1 to 4 at 25°C for methanol and H2O vapor is as follows: Figure 9 As shown.

[0093] 6. Material pore size distribution

[0094] The pore size distribution is obtained by fitting the CO2(273K) adsorption curve to a commercial density functional theory (DFT) or Monte Carlo (MC) model.

[0095] The CO2(273K) adsorption isotherm is loaded into the Quantachrome software AsiQwin and the CO2 at 273K on carbon (MC or DFT Model) model is selected to fit the material's pore size distribution.

[0096] The NLDFT and MC model assumes that the adsorption isotherm of a material is obtained by multiplying the adsorption of an infinite number of "single pores" by their relative distribution of coverage pore size range. Given an adsorbate / adsorbent system, an isotherm (also called kernel, or influence function) can be obtained by DFT or MC simulation. The pore size distribution curve of the sample can be derived by solving the equation with the fast non-negative least squares method to fit the measured adsorption isotherm.

[0097] The pore size distribution of the ZIF-1001 to ZIF-1004 materials prepared in Examples 1 to 4 calculated by the CO2 adsorption isotherm at 273K is shown in Figure 10 Figure 1.

Claims

1. A method of making a zeolitic imidazolate framework material, characterized by, The method comprises the following steps: The mixture of zinc salt, triazole ligand, imidazole ligand and solvent is heated to react; The zinc salt is zinc nitrate; The triazoles ligand is ; The imidazolide ligand is , , , , or ; The molar ratio of the triazole ligand to the imidazole ligand is 4:6~2:1; the molar ratio of the zinc salt to the triazole ligand is 1:(1~2); The solvent is one or more of amide solvent, alcohol solvent and halogenated alkane solvent; the amide solvent is DMF; the alcohol solvent is isobutyl alcohol; the halogenated alkane solvent is dichloromethane; The temperature of the heating reaction is 80~120℃; The framework structure of the zeolitic imidazolate framework material is composed of triazole ligand-based connecting units and imidazole ligand-based connecting units; The zeolitic imidazolate framework material is a prismatic crystal, and its space group is P212121; The zeolitic imidazolate framework material has NPO topology.

2. The production method according to claim 1, wherein The zinc salt is zinc nitrate hexahydrate.

3. The production method according to claim 1, wherein The solvent is a mixed solvent of amide solvent and alcohol solvent, and the volume ratio of the amide solvent to the alcohol solvent is 1:(2~5); Alternatively, the solvent is a mixed solvent of amide solvent and halogenated alkane solvent, and the volume ratio of the amide solvent to the halogenated alkane solvent is 1:(2~5).

4. The production method according to any one of claims 1 to 3, wherein The molar volume ratio of the triazole ligand to the solvent is 0.035~0.65 mol / L; And / or, the molar volume ratio of the imidazole ligand to the solvent is 0.025~0.25 mol / L; And / or, the molar volume ratio of the zinc salt to the solvent is 0.035~0.35 mol / L.

5. The production method according to claim 4, wherein The molar volume ratio of the triazole ligand to the solvent is 0.04~0.4 mol / L; And / or, the molar volume ratio of the imidazole ligand to the solvent is 0.05~0.06 mol / L; And / or, the molar volume ratio of the zinc salt to the solvent is 0.05~0.06 mol / L.

6. The production method according to claim 5, wherein The molar volume ratio of the triazole ligand to the solvent is 0.1~0.12 mol / L.

7. The production method according to claim 1, wherein The heating reaction is carried out in the presence of a base.

8. The production method according to claim 1, wherein The temperature of the heating reaction is 80~100℃; And / or, the heating reaction is carried out in the presence of an organic amine.

9. The production method according to claim 8, wherein The temperature of the heating reaction is 80~90℃; And / or, the heating reaction is carried out in the presence of an organic amine; wherein the organic amine is tetra-n-butylammonium hydroxide.

10. A zeolitic imidazolate framework material prepared by the preparation method of any one of claims 1 to 9.

11. The zeolitic imidazolate framework material of claim 10, wherein, The zeolitic imidazolate framework material comprises 3~12-membered ring channels.

12. The zeolitic imidazolate framework material of claim 11, wherein, The framework structure of the zeolitic imidazolate framework material is composed of triazole ligand-based connecting units and imidazole ligand-based connecting units, and the molar ratio of the triazole ligand-based connecting units to the imidazole ligand-based connecting units is (3~5):

1.

13. Use of the zeolitic imidazolate framework material of any one of claims 10-12 in flue gas carbon capture.

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