Indium-based metal organic framework material and preparation method and application thereof

Abstract

The invention belongs to the technical field of gas adsorption separation, and particularly relates to an indium-based metal organic framework material as well as a preparation method and application thereof. Soluble indium salt and triphenylphosphine oxide tricarboxylic acid are jointly dissolved in a solvent to obtain a mixture, then the mixture is transferred into a reaction kettle, a solvothermal reaction is carried out, and the indium-based metal organic framework material is obtained. According to the method, a proper pore diameter and pore channel chemical environment is provided for gas molecule adsorption separation, a new idea is provided for separation of acetylene in a C2H2 mixture, the requirement for high purity of acetylene in the chemical industry and other fields is expected to be met, and the method has wide application potential in acetylene production and complex gas treatment.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas adsorption separation, and in particular relates to an indium-based metal organic framework material and a preparation method and application thereof. Background Art

[0002] Acetylene (C2H2) is an important industrial raw material, widely used in synthetic fibers, the production of alkyne derivatives, and other high-value-added chemicals. In industrial production, acetylene typically contains small amounts of carbon dioxide (CO2) and ethylene (C2H4). Direct use of this mixture not only reduces product quality but also adversely affects subsequent reactions and production processes. Traditional separation methods, such as cryogenic distillation, are energy-intensive, costly, and complex.

[0003] Currently, a variety of metal-organic framework materials for acetylene separation have been disclosed. However, existing metal-organic framework materials have technical defects such as poor stability, such as poor heat resistance, acid and alkali resistance, which shortens the service life of the metal-organic framework materials. Summary of the Invention

[0004] To address the shortcomings of the aforementioned prior art, the present invention provides an indium-based metal-organic framework material, its preparation method, and its application. The present invention utilizes a soluble indium salt and triphenylphosphine oxide tricarboxylic acid as raw materials, disperses them in a solvent consisting of N,N-dimethylformamide and fluoroboric acid, and undergoes a solvothermal reaction to obtain the indium-based metal-organic framework material. The indium-based metal-organic framework material of the present invention is used as an adsorption separation material to purify an acetylene mixture, overcoming the technical drawbacks of both conventional separation methods and existing metal-organic framework materials.

[0005] Based on the above technical objectives, the present invention is achieved by adopting the following technical solutions: The present invention protects an indium-based metal organic framework material, the chemical formula of which is C 42 H 30 In3O 18 P2; crystallographic data: monoclinic system, space group P21 / c, unit cell parameters: a=15.407(2), b=13.1276(18), c=20.156(3)Å, α=90°, β=109°, γ=90°, V=3850.5(9)Å 3 , Z=2, F(000)=1206.0.

[0006] The present invention also provides a method for preparing an indium-based metal organic framework material, comprising the following steps: Soluble indium salt and triphenylphosphine oxide tricarboxylic acid are dissolved in a solvent to obtain a mixture; and then the mixture is subjected to a solvent thermal reaction to obtain an indium-based metal organic framework material.

[0007] The solvent consists of N,N-dimethylformamide and fluoroboric acid. N,N-dimethylformamide removes the proton on triphenylphosphine oxide tricarboxylic acid to form structure, With In 3+ Since both are strong Lewis acids and bases, their coordination reaction is fast and violent, making it difficult to obtain large crystals that meet the test size of a single crystal diffractometer, making their structural testing and analysis difficult. At this time, after adding fluoroboric acid, fluoroboric acid first reacts with Structural bonding to slow down In 3+ and The rate of structural coordination is reduced, thereby slowing down the crystallization rate, which is conducive to the growth of large single crystals.

[0008] Preferably, the molar ratio of the soluble indium salt to triphenylphosphine oxide tricarboxylic acid is 1-2:0.2; if it is not within this range, an amorphous state or a mixed solution is easily formed after solvent thermal treatment.

[0009] Preferably, the volume ratio of N,N-dimethylformamide to fluoroboric acid is 3:0.1-0.3; if it is not within this range, an amorphous state or a mixed solution is easily formed after solvent thermal treatment.

[0010] Preferably, the volume ratio of triphenylphosphine oxide tricarboxylic acid to fluoroboric acid is 0.02 mmol: 0.1-0.3 mL; too little fluoroboric acid will result in amorphous crystals, while too much fluoroboric acid will dissolve / destroy the triphenylphosphine oxide tricarboxylic acid ligand, resulting in the formation of a solution.

[0011] Preferably, the solvothermal reaction conditions are: reaction at 100° C. to 130° C. for 72 h to 96 h.

[0012] The present invention also protects the application of the indium-based metal organic framework material in the preparation of acetylene adsorption and separation materials.

[0013] Preferably, the indium-based metal-organic framework material is used for the adsorptive separation of acetylene from acetylene / carbon dioxide or the adsorptive separation of acetylene from acetylene / ethylene.

[0014] Preferably, the indium-based metal-organic framework material is activated before adsorption separation, and the activation comprises the following steps: soaking the indium-based metal-organic framework material in acetonitrile for 3 to 4 days, and regularly replacing fresh acetonitrile, and finally removing the acetonitrile molecules in the crystal pores of the indium-based metal-organic framework material by vacuum pumping at 80°C.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention provides a chemical formula C 42 H 30 In3O 18 The indium-based metal-organic framework material of the present invention has the following characteristics: (1) the abundant benzene rings in the triphenylphosphine oxide tricarboxylate ligand form a CH...π interaction with the C2H2 molecule; (2) the O atom of the P=O functional group in the triphenylphosphine oxide tricarboxylate ligand has a lone pair of electrons, which can form a CH...O interaction with the C2H2 molecule; the above forces can effectively capture acetylene molecules, realize the adsorption of acetylene, and simultaneously realize the separation of acetylene from CO2 and ethylene; the pore size of the indium-based metal-organic framework material is 4.5 angstroms to 7.5 angstroms, which is an effective pore size for separating C2H2 (the advantage of this pore size for separating C2H2 is the existing technology).

[0016] 2. The present invention uses a soluble indium salt and triphenylphosphine oxide tricarboxylic acid as raw materials, mixes them in a solvent consisting of N,N-dimethylformamide and fluoroboric acid, and conducts a solvothermal reaction. During the reaction, the indium metal and the triphenylphosphine oxide tricarboxylic acid ligands self-assemble through coordination bonds to produce an indium-based metal-organic framework material. The fluoroboric acid acts as a modulator to slow the rate of coordination bond formation between the indium metal and the triphenylphosphine oxide tricarboxylic acid ligands, thereby growing larger single crystals. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 Schematic diagram of the structure of the indium-based metal-organic framework material of the present invention.

[0018] Figure 2 This is the X-ray powder diffraction pattern of the indium-based metal-organic framework material in Example 1.

[0019] Figure 3 This is the N2 adsorption-desorption isotherm and pore size distribution diagram of the indium-based metal-organic framework material in Example 1 at 77K.

[0020] Figure 4 This is the isothermal adsorption spectrum of the indium-based metal organic framework material of Example 1 for carbon dioxide, acetylene and ethylene at 298K.

[0021] Figure 5 This is the adsorption heat map of carbon dioxide, acetylene and ethylene of the indium-based metal-organic framework material in Example 1.

[0022] Figure 6 This is a graph showing the IAST separation coefficients of the indium-based metal organic framework material of Example 1 for acetylene / carbon dioxide and acetylene / ethylene.

[0023] Figure 7The dynamic penetration curves of the indium-based metal organic framework material of Example 1 at room temperature are shown in FIG. (a) shows the dynamic penetration curve of acetylene / carbon dioxide, and (b) shows the dynamic penetration curve of acetylene / ethylene.

[0024] Figure 8 This is the XRD pattern of the indium-based metal-organic framework material in Example 1 after being immersed in different acidic and alkaline solutions.

[0025] Figure 9 This is the thermogravimetric analysis diagram of the indium-based metal-organic framework material in Example 1. DETAILED DESCRIPTION

[0026] In order to more clearly understand the above-mentioned objectives, features and advantages of the present invention, the scheme of the present invention will be further described below. It should be noted that, in the absence of conflict, the embodiments of the present invention and the features therein can be combined with each other.

[0027] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein; it is obvious that the embodiments in the specification are only part of the embodiments of the present invention, rather than all the embodiments.

[0028] Considering the problems of high energy consumption, high cost and complicated operation in the prior art low temperature distillation method, the present invention provides an indium-based metal organic framework material, the chemical formula of which is: C 42 H 30 In3O 18 P2; crystallographic data: belongs to the monoclinic system, space group P21 / c, unit cell parameters: a=15.407(2), b=13.1276(18), c=20.156(3)Å, α=90°, β=109°, γ=90°, V=3850.5(9)Å 3 , Z=2, F(000)=1206.0. By filling the indium-based metal-organic framework material of the present invention into a separation column and introducing a C2H2 / CO2 or C2H2 / C2H4 mixed gas, acetylene is separated from carbon dioxide or ethylene, resolving the technical drawbacks of the cryogenic distillation method. Furthermore, based on the indium-based metal-organic framework material of the present invention, a new separation process with high efficiency, low energy consumption, and low cost has been developed to achieve high-purity separation of acetylene from an acetylene mixture, which has important industrial application value and technical significance.

[0029] In addition, it has been verified that the indium-based metal-organic framework material of the present invention has excellent acid and alkali resistance and thermal stability, overcoming the technical defect of poor stability of the existing metal-organic framework material for acetylene separation.

[0030] The technical solution of the present invention is described in detail below using embodiments, which are as follows: Example 1 A method for preparing an indium-based metal-organic framework material comprises the following steps: In(NO3)3·xH2O (0.1 mmol) and triphenylphosphine oxide tricarboxylic acid (0.02 mmol) were dissolved in a DMF / HBF4 mixed solvent (volume ratio of 3:0.1, totaling 3.1 mL) to obtain a mixture; the mixture was then transferred to a stainless steel reactor lined with polytetrafluoroethylene and placed in a 120°C oven for reaction for 96 hours. After the reaction was completed, the mixture was cooled to room temperature and filtered to obtain light yellow block crystals. The crystals were washed three times with DMF to remove unreacted ligands to obtain an indium-based metal-organic framework material.

[0031] Example 2 A method for preparing an indium-based metal-organic framework material comprises the following steps: In(NO3)3·xH2O (0.15 mmol) and triphenylphosphine oxide tricarboxylic acid (0.02 mmol) were dissolved in a DMF / HBF4 mixed solvent (volume ratio of 3:0.2, totaling 3.2 mL) to obtain a mixture; the mixture was then transferred to a stainless steel reactor lined with polytetrafluoroethylene and placed in a 100°C oven to react for 84 hours. After the reaction was completed, the temperature was cooled to room temperature and light yellow block crystals were obtained by filtration. The crystals were washed three times with DMF to remove unreacted ligands to obtain an indium-based metal-organic framework material.

[0032] Example 3 A method for preparing an indium-based metal-organic framework material comprises the following steps: In(NO3)3·xH2O (0.2 mmol) and triphenylphosphine oxide tricarboxylic acid (0.02 mmol) were dissolved in a DMF / HBF4 mixed solvent (the volume ratio of the two was 3:0.3, a total of 3.3 mL) to obtain a mixture; the mixture was then transferred to a stainless steel reactor lined with polytetrafluoroethylene material and placed in a 130°C oven to react for 72 hours. After the reaction was completed, it was cooled to room temperature and filtered to obtain light yellow block crystals. The crystals were washed three times with DMF to wash away the unreacted ligands to obtain an indium-based metal-organic framework material.

[0033] In Examples 1 to 3 of the present invention all produce indium-based metal-organic framework materials with excellent acetylene adsorption and separation performance. The indium-based metal-organic framework material of Example 1 is used as an example for research. The specific research methods and results are shown below: Table 1 Crystallographic parameters of indium-based metal organic framework materials in Example 1 The indium-based metal-organic framework material is activated before use to remove solvent molecules in the pores of the indium-based metal-organic framework material. The activation method is as follows: the indium-based metal-organic framework material is immersed in acetonitrile for 3 days, and fresh acetonitrile solvent is replaced every 12 hours. Finally, the acetonitrile is pumped in a vacuum at 80°C for 10 hours to remove the acetonitrile solvent in the crystal pores of the indium-based metal-organic framework material to obtain an activated indium-based metal-organic framework material.

[0034] The preparation principle diagram of the indium-based metal organic framework material of the present invention is as follows Figure 1 shown.

[0035] Depend on Figure 2 It can be seen that the powder X-ray diffraction of the indium-based metal-organic framework material is highly consistent with the simulation pattern, proving that the synthesized indium-based metal-organic framework material has high purity and good crystallinity.

[0036] Single gas adsorption test: 100 mg of indium-based metal-organic framework material was prepared for activation, and the N2 adsorption isotherm of the activated indium-based metal-organic framework material at 77 K was obtained using a 3-Flex specific surface area measurement and pore size analyzer (the purity of the N2 used was 99.999%). The pore size of the activated indium-based metal-organic framework material was analyzed using the DFT model, as shown in Figure 2. Figure 3 As shown, the pore size of the activated indium-based metal-organic framework material is between 0.55nm and 0.75nm.

[0037] 100 mg of indium-based metal-organic framework material was prepared for activation. The adsorption isotherms of CO2, C2H2, and C2H4 at 273K, 283K, and 298K were obtained using a 3-Flex surface area analyzer and a pore size analyzer. The purity of the CO2, C2H2, and C2H4 used was 99.999%. The adsorption data at 298 K are shown in Figure 2. Figure 4 As shown by Figure 4 It can be seen that the activated indium-based metal-organic framework material exhibits a higher adsorption capacity for acetylene than for carbon dioxide and ethylene, proving that the activated indium-based metal-organic framework material preferentially adsorbs acetylene.

[0038] Adsorption heat test: Using the above Figure 4 The measured single-component gas adsorption isotherms at 273K, 283K, and 298K and the Clausius-Clapeyron equation: , the adsorption heat of activated indium-based metal-organic framework materials was calculated, such as Figure 5 As shown by Figure 5 It can be seen that the acetylene adsorption heat of the activated indium-based metal-organic framework material in Example 1 is higher than that of carbon dioxide and ethylene, which proves that the action force of the activated indium-based metal-organic framework material on acetylene is stronger than that on carbon dioxide and ethylene.

[0039] Here, Q st is the heat of adsorption (kJ / mol), R is the universal gas constant, T is the temperature, p is the pressure (kPa), and q is the adsorption capacity (mmol / g).

[0040] Optional testing: In order to evaluate the gas separation ability of activated indium-based metal-organic framework materials, based on the above Figure 4 The single gas adsorption isotherms were used to calculate the IAST of the adsorption of C2H2 / CO2 (50:50, v / v) and C2H2 / C2H4 (50:50, v / v), and the IAST selectivity coefficients of the activated indium-based metal-organic framework material for the two mixtures were obtained, such as Figure 6 As shown, the selectivities of the activated indium-based metal-organic framework material in Example 1 at 1 bar reached 7.4 and 2.0, respectively, proving that the indium-based metal-organic framework material has a better selectivity for acetylene / carbon dioxide than for acetylene / ethylene.

[0041] Dynamic penetration testing: The dynamic penetration test of indium-based metal-organic framework materials was carried out as follows: 0.6g of activated indium-based metal-organic framework material powder was placed in a stainless steel separation column, and the adsorption bed was purged with helium (He, ≥99.999%) at a rate of 20mL / min. After the bed temperature was lowered to 298K, a C2H2 / CO2 or C2H2 / C2H4 mixed gas (50:50, v / v) was introduced at a flow rate of 2mL / min, and the outlet gas was analyzed by mass spectrometry. The data detected by the mass spectrometer were used to plot the Figure 7 It was found that carbon dioxide and ethylene passed through before acetylene, proving that the indium-based metal-organic framework material of Example 1 had good separation performance for both C2H2 / CO2 and C2H2 / C2H4 mixtures.

[0042] The indium-based metal organic framework material of Example 1 was immersed in different solutions with pH values ​​of 2, 3, 5, 9, 11, and 12 for 2 h. Figure 8 The main peak in the XRD spectrum remains consistent, indicating that the skeleton of the In-MOF structure remains stable in the pH range of 2 to 11 after immersion. This result shows that the synthesized indium-based metal-organic framework material has high acid-base stability.

[0043] The indium-based metal organic framework material of Example 1 was subjected to thermogravimetric analysis. Figure 9 The results show that the skeleton of the indium-based metal-organic framework material remains stable below 400°C, indicating excellent thermal stability.

[0044] The above description is merely a specific embodiment of the present invention, which enables those skilled in the art to understand or implement the present invention. Although detailed descriptions have been made with reference to the aforementioned embodiments, those skilled in the art should understand that they may still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents; and such modifications or replacements do not deviate from the essence of the corresponding technical solutions within the scope of the technical solutions of the embodiments, and they should all be included in the scope of protection of the claims.

Claims

1. An indium-based metal-organic framework material, characterized in that: The chemical formula of indium-based metal organic framework material is C 42 H 30 In3O 18 P2; crystallographic data: monoclinic system, space group P21 / c, unit cell parameters: a=15.407(2), b=13.1276(18), c=20.156(3)Å, α=90°, β=109°, γ=90°, V=3850.5(9)Å 3 , Z=2, F(000)=1206.

0.

2. A method for preparing the indium-based metal-organic framework material according to claim 1, characterized in that: The steps include: Dissolving a soluble indium salt and triphenylphosphine oxide tricarboxylic acid in a solvent to obtain a mixture; and then subjecting the mixture to a solvothermal reaction to obtain an indium-based metal-organic framework material; The solvent consists of N,N-dimethylformamide and fluoroboric acid.

3. The method for preparing an indium-based metal-organic framework material according to claim 2, wherein: The molar ratio of the soluble indium salt to triphenylphosphine oxide tricarboxylic acid is 1-2:0.

2.

4. The method for preparing an indium-based metal-organic framework material according to claim 2, wherein: The volume ratio of N,N-dimethylformamide to fluoroboric acid is 3:0.1~0.

3.

5. The method for preparing an indium-based metal-organic framework material according to claim 2, wherein: The volume ratio of triphenylphosphine oxide tricarboxylic acid to fluoroboric acid is 0.02 mmol: 0.1 mL to 0.3 mL.

6. The method for preparing an indium-based metal-organic framework material according to claim 2, wherein: The conditions of the solvent thermal reaction are: reaction at 100°C~130°C for 72h~96h.

7. Use of the indium-based metal organic framework material according to claim 1 in preparing acetylene adsorption and separation materials.

8. The use according to claim 7, characterized in that Indium-based metal-organic framework materials are used for the adsorption separation of acetylene from acetylene / carbon dioxide or the adsorption separation of acetylene from acetylene / ethylene.

9. The use according to claim 7, characterized in that The indium-based metal-organic framework material is activated before adsorption and separation. The activation includes the following steps: soaking the indium-based metal-organic framework material in acetonitrile for 3 to 4 days, and regularly replacing fresh acetonitrile, and finally removing acetonitrile molecules in the crystal pores of the indium-based metal-organic framework material.

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