A borate-based metal organic framework compound and a preparation method thereof

Abstract

The application belongs to the technical field of new materials, and relates to a borate metal organic framework compound and a preparation method thereof. First, a metal salt is dissolved in N,N-dimethylformamide, and then boric acid and 2-methyl imidazole are dissolved in 1-500 ml ultrapure water. The obtained solutions are mixed in proportion, transferred to a reaction kettle, stirred uniformly, sealed, heated to 150-200 DEG C, cooled to room temperature, sequentially subjected to water washing and filtration, and dried under vacuum to obtain a borate metal organic framework single crystal. The preparation process is simple, safe and convenient, and low in cost. The borate metal organic framework structure prepared can be used for gas storage, catalysis, and derivation of porous carbon materials containing boron and metal borides.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of new materials, and relates to a borate metal organic framework compound and a preparation method thereof. BACKGROUND

[0002] Metal-Organic Frameworks (MOFs) are a kind of porous network structure formed by self-assembly of inorganic metal ions (or metal clusters) and organic ligands through coordination. MOFs are also called porous coordination polymers. Due to the rich pore structure of the material, MOFs have high specific surface area and porosity, so MOFs show great potential applications in gas adsorption, storage, separation, drug delivery, catalysis and other fields (Park K S, Ni Z, et al. Exceptional chemical and thermal stability of zeolitic imidazolate frameworks. Proceedings of the National Academy of Sciences, 2006, 103 (27): 10186-10191; Banerjee R, Phan A, Wang B, et al. High-throughput synthesis of zeolitic imidazolate frameworks and application to CO2 capture. Science, 2008, 319 (5865): 939-943).

[0003] ​In recent years, boron and its compounds have shown a variety of properties and functions due to their unique structural characteristics, and have wide application prospects in biochemistry, material science, catalytic chemistry and other fields. In recent years, relevant literatures have been published one after another, such as the unique catalytic properties of boron nitride in the field of catalysis (Grant J T, Carrero C A, Goeltl F, et al. Selective oxidative dehydrogenation of propane to propene using boron nitride catalysts. Science, 2016, 354(6319): 1570-1573), and the unique CO2 capture properties of BIF series (Zheng S, Wu T, Zhang J, et al. Porous metal carboxylate boron imidazolate frameworks. Angewandte Chemie, 2010, 122(31): 5490-5494.)

[0004] So far, only the metal organic framework material of BIF series contains boron element (Zhang J, Wu T, Zhou C, et al. Zeolitic boron imidazolate frameworks. Angewandte Chemie, 2009, 121(14): 2580-2583), and the synthesis process of such MOFs needs to use boron-containing ligands, but the chemical structure of boron is very stable, and the synthesis process of the ligand is complex. Therefore, to enrich boron-containing MOFs materials, it is necessary to overcome the above problems and develop a new route for the synthesis of boron-containing MOFs. SUMMARY

[0005] The present application aims to overcome the shortcomings of the prior art and provide a preparation method of borate metal organic framework compound by solvothermal method.

[0006] In order to achieve the above-mentioned purpose, the chemical formula of the borate metal organic framework compound according to the present application is expressed as: Zn2(BO3)C8H 12 N4, and the single crystal cell parameters are: tetragonal system, Pba2 space group, alpha = 90°, beta = 90°, gama = 90°, Z = 2, The space stacking structure is a three-dimensional structure.

[0007] The specific process for preparing the borate metal organic framework compound according to the present application comprises the following steps:

[0008] 1) 0.0001-10.0 mol metal salt is dissolved in 1-500 ml N,N-dimethylformamide (DMF),

[0009] 2) 0.001-10.0 mol boric acid and 0.001-10.0 mol 2-methylimidazole are dissolved in 1-500 ml ultrapure water;

[0010] 3) the solutions obtained in step 1) and step 2) are mixed in a ratio of 1:1 by volume, transferred to a reaction kettle, stirred uniformly, sealed, heated to 150-200°C at a rate of 1-5°C / min, reacted for 6-168 hours, then reduced to room temperature at a rate of 0.2-5°C / min, sequentially subjected to 3-5 times of suction filtration and water washing, and dried at 60-80°C under vacuum for 12 h to obtain a borate metal organic framework single crystal.

[0011] The metal salt in the application is an inorganic metal salt such as nitrate, sulfate or chloride, preferably zinc nitrate, zinc sulfate or zinc chloride.

[0012] The boric acid and 2-methylimidazole in the application are both commercial products with a purity of more than 98%.

[0013] Compared with the prior art, the application has the advantages of simple preparation process, convenient and safe operation, low cost, and the borate metal organic framework structure prepared can be used for gas storage, catalysis, and derivation of porous carbon materials containing boron, metal borides, etc. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A digital photo of a zinc borate organic framework compound single crystal prepared in Example 1 of the application.

[0015] Figure 2 A structural unit of a zinc borate organic framework compound prepared in Example 1 of the application.

[0016] Figure 3 An X-ray diffraction spectrum of a zinc borate organic framework compound prepared in Example 1 of the application.

[0017] Figure 4 Thermogravimetric spectra of a zinc borate organic framework compound prepared in Example 1 of the application under air and nitrogen. DETAILED DESCRIPTION

[0018] The application is further described below in combination with examples, but is not limited thereto.

[0019] The raw materials used in the examples of the application are all commercially available products without any further treatment; the instruments, if not specially stated, can be obtained from commercial channels.

[0020] Example 1:

[0021] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0022] 1) Dissolve 2 g of zinc nitrate in 35 ml of N,N-dimethylformamide solution;

[0023] 2) Dissolve 2.2 g of 2-methylimidazole and 4.3 g of boric acid in 35 ml of ultrapure water in turn;

[0024] 3) Transfer the zinc nitrate solution in step 1) and the 2-methylimidazole and boric acid in step 2) into a 100 ml reaction kettle polytetrafluoroethylene liner, stir uniformly, and seal;

[0025] 4) Transfer the reaction kettle in step 3) into an oven, heat to 160°C at a rate of 5°C / min for 120 hours, and then cool to room temperature at a rate of 0.4°C / min;

[0026] 5) The crystal generated in step 4) is washed with ultrapure water for three times, transferred to a vacuum drying oven, and dried at 60°C for 12 h to prepare the zinc borate organic framework compound.

[0027] The digital photo of the single crystal of the zinc borate organic framework compound prepared in this example is shown in Figure 1 As shown in Figure 1 , the structure of the crystal is very complete and no obvious defects appear; the structure unit is shown in Figure 2 , the boron element is successfully coordinated into the MOFs structure in the form of borate; the X-ray diffraction spectrum is shown in Figure 3 , the crystallinity of the single crystal is very high and no impurities appear; the thermogravimetric spectrum under air and nitrogen is shown in Figure 4 As can be seen from the figure, the compound prepared in this example has very good thermal stability.

[0028] Example 2:

[0029] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0030] 1) Dissolve 1 g of zinc nitrate in 15 ml of N,N-dimethylformamide solution;

[0031] 2) Dissolve 1.1 g of 2-methylimidazole and 2.1 g of boric acid in 15 ml of ultrapure water in turn;

[0032] 3) Transfer the zinc nitrate solution in step 1) and the 2-methylimidazole and boric acid in step 2) into a 50 ml reaction kettle polytetrafluoroethylene liner, stir uniformly, and seal;

[0033] 4) The reactor from step 3) is transferred to an oven and heated to 150 °C at a rate of 3 °C / min for 96 hours and then cooled to room temperature at a rate of 5 °C / min;

[0034] 5) The crystals generated in step 4) are washed with ultra-pure water by suction filtration three times and transferred to a vacuum drying oven at 60 °C for 12 h.

[0035] Example 3:

[0036] The process for preparing the borate metal organic framework compound of this example comprises the following steps:

[0037] 1) 0.5 g of zinc nitrate is dissolved in 15 ml of N,N-dimethylformamide solution;

[0038] 2) 0.6 g of 2-methylimidazole, 0.75 g of boric acid are sequentially dissolved in 15 ml of ultra-pure water;

[0039] 3) The zinc nitrate solution from step 1) and the 2-methylimidazole, boric acid from step 2) are transferred to a 50 ml reactor with a polytetrafluoroethylene liner, stirred until homogeneous and sealed;

[0040] 4) The reactor from step 3) is transferred to an oven and heated to 200 °C at a rate of 5 °C / min for 72 hours and then cooled to room temperature at a rate of 1 °C / min;

[0041] 5) The crystals generated in step 4) are washed with ultra-pure water by suction filtration three times and transferred to a vacuum drying oven at 80 °C for 12 h.

[0042] Example 4:

[0043] The process for preparing the borate metal organic framework compound of this example comprises the following steps:

[0044] 1) 1.0 g of zinc chloride is dissolved in 15 ml of N,N-dimethylformamide solution;

[0045] 2) 1.5 g of 2-methylimidazole, 1.75 g of boric acid are sequentially dissolved in 15 ml of ultra-pure water;

[0046] 3) The zinc nitrate solution from step 1) and the 2-methylimidazole, boric acid from step 2) are transferred to a 50 ml reactor with a polytetrafluoroethylene liner, stirred until homogeneous and sealed;

[0047] 4) The reactor from step 3) is transferred to an oven and heated to 180 °C at a rate of 3 °C / min for 120 hours and then cooled to room temperature at a rate of 3 °C / min;

[0048] 5) The crystals generated in step 4) are washed with ultra-pure water by suction filtration three times and transferred to a vacuum drying oven at 80°C for 12 h.

[0049] Example 5:

[0050] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0051] 1) 2.0 g of zinc sulfate is dissolved in 35 ml of N,N-dimethylformamide solution;

[0052] 2) 2.2 g of 2-methylimidazole and 3.1 g of boric acid are sequentially dissolved in 35 ml of ultra-pure water;

[0053] 3) The zinc nitrate solution in step 1) and the 2-methylimidazole and boric acid in step 2) are transferred to a 100 ml reaction kettle PTFE liner, stirred uniformly, and sealed;

[0054] 4) The reaction kettle in step 3) is transferred to an oven, heated to 150°C at a rate of 0.5°C / min for 144 h, and then cooled to room temperature at a rate of 0.5°C / min;

[0055] 5) The crystals generated in step 4) are washed with ultra-pure water by suction filtration three times and transferred to a vacuum drying oven at 60°C for 12 h.

[0056] Example 6:

[0057] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0058] 1) 0.5 g of cobalt nitrate is dissolved in 15 ml of N,N-dimethylformamide solution;

[0059] 2) 0.6 g of 2-methylimidazole and 0.75 g of boric acid are sequentially dissolved in 15 ml of ultra-pure water;

[0060] 3) The zinc nitrate solution in step 1) and the 2-methylimidazole and boric acid in step 2) are transferred to a 50 ml reaction kettle PTFE liner, stirred uniformly, and sealed;

[0061] 4) The reaction kettle in step 3) is transferred to an oven, heated to 180°C at a rate of 3°C / min for 72 h, and then cooled to room temperature at a rate of 2°C / min;

[0062] 5) The crystals generated in step 4) are washed with ultra-pure water three times and transferred to a vacuum drying oven at 80°C for 12 h.

[0063] Example 7:

[0064] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0065] 1) 1.5 g of copper nitrate was dissolved in 35 ml of N,N-dimethylformamide solution;

[0066] 2) 1.6 g of 2-methylimidazole, 2.3 g of boric acid were sequentially dissolved in 35 ml of ultrapure water;

[0067] 3) The zinc nitrate solution in step 1) and the 2-methylimidazole, boric acid in step 2) were transferred to a 100 ml reaction kettle polytetrafluoroethylene liner, stirred uniformly, and sealed;

[0068] 4) The reaction kettle in step 3) was transferred to an oven, heated to 200°C at a rate of 5°C / min for 48 hours, and then cooled to room temperature at a rate of 2°C / min;

[0069] 5) The crystals generated in step 4) were washed with ultrapure water by suction filtration three times and transferred to a vacuum drying oven at 80°C for 12 h.

[0070] Example 8:

[0071] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0072] 1) 1.7 g of nickel nitrate was dissolved in 35 ml of N,N-dimethylformamide solution;

[0073] 2) 2.0 g of 2-methylimidazole, 2.3 g of boric acid were sequentially dissolved in 35 ml of ultrapure water;

[0074] 3) The zinc nitrate solution in step 1) and the 2-methylimidazole, boric acid in step 2) were transferred to a 100 ml reaction kettle polytetrafluoroethylene liner, stirred uniformly, and sealed;

[0075] 4) The reaction kettle in step 3) was transferred to an oven, heated to 150°C at a rate of 0.5°C / min for 60 hours, and then cooled to room temperature at a rate of 1°C / min;

[0076] 5) The crystals generated in step 4) were washed with ultrapure water by suction filtration three times and transferred to a vacuum drying oven at 60°C for 12 h.

[0077] Example 9:

[0078] The process for preparing the borate metal organic framework compound in this example includes the following steps:

[0079] 1) 0.7 g of ferrous chloride was dissolved in 15 ml of N,N-dimethylformamide solution;

[0080] 2) 1.0 g of 2-methylimidazole and 1.3 g of boric acid were sequentially dissolved in 15 ml of ultrapure water;

[0081] 3) The zinc nitrate solution in step 1) and the 2-methylimidazole and boric acid in step 2) were transferred into a 50-ml reaction kettle with a polytetrafluoroethylene inner liner, stirred uniformly, and sealed;

[0082] 4) The reaction kettle in step 3) was transferred into an oven, and heated to 180°C at a rate of 5°C / min for 60 hours, and then cooled to room temperature at a rate of 3°C / min;

[0083] 5) The crystals generated in step 4) were suction-filtered and washed with ultrapure water three times, and transferred into a vacuum drying oven at 80°C for 12 hours.

Claims

1. A method for preparing a borate metal-organic framework compound, characterized in that... The specific process includes the following steps: 1) Dissolve 2g of zinc nitrate in 35ml of N,N-dimethylformamide solution; 2) Dissolve 2.2g of 2-methylimidazole and 4.3g of boric acid in 35ml of ultrapure water; both boric acid and 2-methylimidazole are commercial products with a purity of over 98%; 3) Transfer the zinc nitrate solution from step 1) and the 2-methylimidazole and boric acid from step 2) into a 100ml reaction vessel lined with polytetrafluoroethylene, stir well, and seal. 4) Transfer the reaction vessel from step 3) to an oven, heat it to 160°C at a rate of 5°C / min and react for 120 hours, then cool it to room temperature at a rate of 0.4°C / min; 5) The crystals generated in step 4) were washed three times with ultrapure water by filtration, and then dried in a vacuum drying oven at 60°C for 12 hours to prepare the zinc borate organic framework compound, whose chemical formula is: Zn2(BO3)C8H 12 N4 has the following single-crystal unit cell parameters: tetragonal crystal system, space group Pba2. alpha=90°, beta=90°, gama=90°, Z = 2, The spatially packed structure is a three-dimensional structure that can be used for gas storage, catalysis, and the derivation of boron-containing porous carbon materials and metal borides.

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