Preparation method and application of zirconium-based amorphous metal-organic framework material Zr-aMOF

Abstract

The application belongs to the technical field of adsorbing materials, and provides a method for preparing a zirconium-based amorphous metal organic framework material Zr-aMOF; the method develops an in-situ hydrolysis strategy, and successfully synthesizes a micro-sized spherical aMOF material through a simple one-step reaction; the material has good acid stability and mechanical stability, is suitable for being used as an HPLC stationary phase material, and after being compounded with a polysaccharide derivative, a chiral stationary phase is obtained, and the chiral stationary phase can be successfully used for separating chiral enantiomers.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of adsorption materials, and particularly relates to a preparation method of a zirconium-based amorphous metal organic framework material Zr-aMOF and application thereof in high performance liquid chromatography (HPLC). BACKGROUND

[0002] Metal-organic framework materials (MOFs) have attracted much attention in the application of chromatographic separation due to their uniform pore size distribution and ordered porous structure, rich structure of organic ligand and multifunctionality and adjustability of metal center, good acid-base stability, etc. From the analysis of chromatographic dynamics, in order to improve the separation performance, the separation material used as the HPLC stationary phase, such as silica gel, alumina, etc. should have uniform geometric shape and homogeneous structure. However, at present, most of the MOFs exist in the form of crystals, and the existence of crystal faces makes it difficult for the crystalline MOFs to form regular spherical particles, and often presents sub-micron size and wide particle size distribution, so that the MOF directly as the chromatographic column material, high back pressure, low theoretical plate number and poor peak shape and other problems occur, thereby affecting its HPLC separation performance.

[0003] The existence of crystal faces and anisotropy in the crystalline MOF is the reason why it is not easy to form spherical particles with uniform surface. In recent years, the development of amorphous MOF (aMOF) materials has attracted widespread attention. The aMOF is a non-crystalline material with basic structural units of MOFs, which retains the porous structure and ligand metal center diversity of MOFs, and has isotropy and flexibility. In the application of chromatographic column packing, the aMOF has more advantages than the crystalline MOF. At present, although more and more aMOFs have been synthesized and used in the fields of catalysis, adsorption, etc., there is no report on the application of aMOF to the HPLC stationary phase. SUMMARY

[0004] In order to overcome the shortcomings of the prior art, the application provides a method for preparing a zirconium-based amorphous metal organic framework material Zr-aMOF. The method develops an in-situ hydrolysis strategy, and successfully synthesizes a micron-sized spherical aMOF material through a simple one-step reaction. The material has good acid stability and mechanical stability, and is suitable for being used as an HPLC stationary phase material. After being compounded with a polysaccharide derivative, a chiral stationary phase is obtained, which can be successfully used for the separation of chiral enantiomers.

[0005] To achieve the above object, the application is implemented by the following technical scheme:

[0006] The first aspect of the present application provides a preparation method of a zirconium-based amorphous metal organic framework material Zr-aMOF, specifically, dissolving a ligand precursor and a zirconium salt in N,N'-dimethylformamide, adding hydrochloric acid and ultrapure water, mixing the obtained suspension, and then performing a heating reaction.

[0007] Preferably, the zirconium salt comprises zirconium tetrachloride and zirconium oxychloride octahydrate.

[0008] Preferably, the ligand precursor is terephthalic dinitrile, dimethyl terephthalate, terephthalic diamide, and derivatives thereof.

[0009] Preferably, the molar ratio of the ligand precursor to the zirconium salt is 1-4: 1-1.2.

[0010] Preferably, the heating reaction is performed at a temperature of 120-220°C for 4-20 hours.

[0011] Preferably, the mixing of the suspension is performed by ultrasonic stirring and dispersion, and the ultrasonic dispersion is performed for 15-30 min.

[0012] Preferably, the volume ratio of hydrochloric acid to water and N,N'-dimethylformamide is 0.3-1.0: 0.2-2.0: 5-20, and 1.2-5 mL of N,N'-dimethylformamide is used per 1 mmol of terephthalic dinitrile.

[0013] The third aspect of the present application provides the use of the zirconium-based amorphous metal organic framework material Zr-aMOF and polysaccharide derivative composite of the second aspect in high-performance liquid chromatography, which is used for the separation of chiral materials, and the zirconium-based amorphous metal organic framework material Zr-aMOF is used as a stationary phase in a high-performance liquid chromatography column.

[0014] The present application also provides a chiral chromatography column, and the chiral stationary phase of the chiral chromatography column comprises the zirconium-based amorphous metal organic framework material Zr-aMOF and the polysaccharide derivative, and the mass ratio of the polysaccharide derivative to the zirconium-based amorphous metal organic framework material Zr-aMOF is 1-0.8: 4-12.

[0015] The chiral chromatography column is prepared by the following method: taking the zirconium-based amorphous metal organic framework material Zr-aMOF and polysaccharide derivative composite material provided by the present application, adding a solvent (such as IPA 20 mL), dispersing sufficiently, pouring into a homogenizer tank, sealing, using methanol as a push liquid, and pressurizing and pushing the composite material suspension into a stainless steel chromatography column tube to obtain the chiral chromatography column.

[0016] The zirconium-based amorphous metal organic framework material Zr-aMOF is compounded with a polysaccharide derivative by the following method: the polysaccharide derivative is placed in a container at room temperature, a solvent (such as THF) is added, and the polysaccharide derivative is fully dissolved under ultrasonic stirring, then the Zr-aMOF is added, ultrasonic stirring is performed, and then the solvent is removed by rotary evaporation, and methanol is used for drying to make the Zr-aMOF uniformly dispersed, vertical standing is performed, the upper small particle suspension and the bottom precipitate are discarded, and the middle suspension particle liquid is collected, and the suspension particle liquid is dried to obtain the composite material.

[0017] Preferably, the polysaccharide derivative includes cellulose-tri-(3,5-dimethylphenyl carbamate), cellulose-tri-(4-methylbenzoate), amylose-tri-(3,5-dimethylphenyl carbamate), and amylose-tri-((S)-a-methylphenyl carbamate).

[0018] Preferably, the mass ratio of the polysaccharide derivative to the zirconium-based amorphous metal organic framework material Zr-aMOF is 1-0.8:4-12. Compared with the prior art, the present application has the following beneficial effects:

[0019] The Zr-aMOF material prepared by the preparation method disclosed in the present application is a dispersible micron-sized microsphere, and the specific size range is 2-4 μm. The Zr-aMOF material can be compounded with various polysaccharide derivatives to obtain a chiral stationary phase for chiral high-performance liquid chromatography separation. The present application has simple and novel synthesis steps, and the obtained material combines the excellent characteristics of MOF materials and amorphous materials. The material has a regular shape, a spherical particle with a uniform surface, and good thermal stability, acid stability and mechanical stability. The composite material obtained by compounding the polysaccharide derivative has chiral chromatographic application capability. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 is a powder diffraction pattern of Zr-aMOF;

[0021] Figure 2 is an infrared spectrum of Zr-aMOF and its ligand;

[0022] Figure 3 is an XPS pattern of Zr-aMOF;

[0023] Figure 4 is a digestion sample of Zr-aMOF 1 HNMR spectrum;

[0024] Figure 5 is a thermogravimetric curve of Zr-aMOF;

[0025] Figure 6 is a nitrogen adsorption-desorption isotherm of Zr-aMOF at 77K;

[0026] Figure 7 pore size distribution curve of the Zr-aMOF;

[0027] Figure 8 SEM image of the Zr-aMOF;

[0028] Figure 9 chiral separation chromatogram of the polysaccharide derivative composite material of the Zr-aMOF;

[0029] Figure 10 SEM image of the polysaccharide derivative composite material of the Zr-aMOF after being subjected to high pressure. DETAILED DESCRIPTION

[0030] The specific embodiments of the present application are described below. It should be noted that the description of these embodiments is used to help understand the present application, but does not constitute a limitation on the present application. In addition, the technical features involved in each of the embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0031] The experimental methods in the following examples are all conventional methods unless otherwise specified. The experimental materials used in the following examples are all commercially available unless otherwise specified.

[0032] Example 1

[0033] According to the following synthesis route, the preparation process of a Zr-aMOF is as follows: p-phenylenedinitrile (4 mmol, 512 mg) and zirconium tetrachloride (2 mmol, 466 mg) are mixed uniformly at room temperature, then N,N'-dimethylformamide (12 mL), 36.5% concentrated hydrochloric acid (0.65 mL) and water (0.35 mL) are added to the mixture to obtain a suspension, the suspension is placed in a reaction kettle with a polytetrafluoroethylene liner and ultrasonically treated for 30 minutes, then the reaction kettle is placed in a forced air drying oven and heated at 220°C for 16 hours, after the reaction, the reaction liquid is slowly cooled to room temperature, centrifuged to obtain a white Zr-aMOF powder, which is an amorphous metal organic framework material Zr-aMOF obtained by the present application.

[0034] Example 2

[0035] According to the following synthesis route, the preparation process of a Zr-aMOF is as follows: dimethyl terephthalate (4 mmol, 777 mg) and zirconium oxychloride octahydrate (2 mmol, 644 mg) are mixed uniformly at room temperature, then N,N'-dimethylformamide (12 mL), 36.5% concentrated hydrochloric acid (0.50 mL) and water (0.30 mL) are added to the mixture to obtain a suspension, the suspension is placed in a reaction kettle polytetrafluoroethylene liner and ultrasonically treated for 30 minutes, then the reaction kettle is placed in a forced air drying oven and heated at 120°C for 10 hours, after reaction, the reaction liquid is slowly cooled to room temperature, centrifuged to obtain a white Zr-aMOF powder, which is an amorphous metal organic framework material Zr-aMOF obtained by the present application.

[0036] The amorphous metal organic framework material Zr-aMOF obtained above is subjected to the following tests:

[0037] (1) Powder X-ray diffraction determination

[0038] The Zr-aMOF material of Example 1 is subjected to powder X-ray diffraction determination, as shown in the X-ray powder diffraction pattern of Figure 1 , the material belongs to an amorphous material.

[0039] (2) Infrared determination

[0040] The Zr-aMOF material of Example 1 is subjected to infrared determination, Figure 2 , which is the infrared spectrum of Zr-aMOF and raw materials, it can be seen that, compared with the raw materials, no cyanogen 2200 cm -1 characteristic peak is observed in the infrared spectrum of Zr-aMOF, indicating that there is no cyanogen in the structure of Zr-aMOF.

[0041] (3) XPS energy spectrum analysis

[0042] The Zr-aMOF material of Example 1 is subjected to XPS full spectrum test, as shown in Figure 3 , the material contains C, O and Zr elements.

[0043] (4) Digestion nuclear magnetic analysis

[0044] The Zr-aMOF material of Example 1 is subjected to nuclear magnetic analysis after strong acid digestion, the spectrum result is as shown in Figure 4 , indicating that the ligand in the material is single terephthalic acid.

[0045] (5) ICP test

[0046] The Zr-aMOF material of Example 1 is subjected to ICP test, the result shows that the content of Zr in the material is 43.99%.

[0047] (6) Thermogravimetric analysis

[0048] The Zr-aMOF material of Example 1 was subjected to thermogravimetric analysis, Figure 5 The thermogravimetric analysis chart of the activated Zr-aMOF can be seen that the material does not start to decompose until after 550°C, having good thermal stability.

[0049] (7) Nitrogen adsorption-desorption curve

[0050] The Zr-aMOF material of Example 1 was subjected to adsorption performance test, Figure 6 The nitrogen adsorption-desorption curve of the activated Zr-aMOF at 77K shows that the BET specific surface area is 305.574 m 2 / g, and the pore size distribution is about 3.8 nm (as shown in the figure). Figure 7

[0051] (8) Scanning electron microscope analysis

[0052] The Zr-aMOF materials of Example 1 and Example 2 were subjected to scanning electron microscope (SEM) analysis, Figure 8 The SEM charts of Zr-aMOF in turn show that the obtained material is composed of microspheres of 2-4 μm, and it can be seen that the spherical shape is regular and the surface is uniform.

[0053] Example 3

[0054] Cellulose-tris-(3,5-dimethylphenylcarbamate) (200 mg) was placed in a round-bottom flask at room temperature, then THF (80 mL) was added, and it was fully dissolved under ultrasonic stirring, then Zr-aMOF (1200 mg) was added, ultrasonic stirring for 3 h, then THF was removed using rotary evaporation, 100 mL of methanol was added after drying, and the composite material was obtained after being fully dispersed by ultrasonic stirring for 10 min, immediately transferred to a 100 mL measuring cylinder, and vertically placed, then the upper 20 mL of the suspension and the bottom precipitate were discarded, and the middle 50 mL of the suspension liquid was collected and dried.

[0055] Example 4

[0056] Take 2000 mg of the composite material in Example 3, add isopropyl alcohol (IPA 20 mL), fully disperse by ultrasonic stirring, immediately pour into a homogenizer tank, seal well, and use methanol as a push liquid, the composite material suspension is filled into a 4.6*100 mm stainless steel chromatographic column tube at a pressure of 5500 psi, the volume of the effluent liquid at the back end of the chromatographic column is monitored by a measuring cylinder, and the volume is 40 mL, the pressure is stopped, the end of the chromatographic column is sealed, and a packed chiral chromatographic column is obtained.

[0057] ​In order to test the chiral separation performance of the Zr-aMOF polysaccharide derivative composite material chromatographic column provided by the application, the packed chiral chromatographic column is subjected to chromatographic analysis of six chiral compounds, including metalaxyl, prothioconazole, trans-1,2-stilbene oxide, 1-(1-naphthyl)ethanol, 1-phenyl ethanol and atropine, the chromatographic conditions are as follows: 0.5 mL / min, the mobile phase of metalaxyl is n-hexane / isopropyl alcohol-80 / 20, the mobile phase of atropine is n-hexane / isopropyl alcohol / trifluoroacetic acid-90 / 10 / 0.1, the mobile phase of the rest of the samples is n-hexane / isopropyl alcohol-90 / 10, and the detection wavelength is 254 nm, and the analysis test results are as follows: Figure 9 .

[0058] Example 5

[0059] After the aMOF material in the chromatographic column that has been subjected to 5500 psi is taken out, scanning electron microscope (SEM) analysis is performed, Figure 10 For the SEM image of the Zr-aMOF, it can be seen that the spherical shape is well maintained, and no collapse deformation occurs.

[0060] As can be seen from the above, the Zr-aMOF material of the application has a micron-level spherical structure, and the composite material obtained by compounding the polysaccharide derivative has the ability of chiral high performance liquid chromatography analysis after being packed into a chromatographic column.

[0061] The embodiments of the application are described in detail above, but the application is not limited to the described embodiments. For those skilled in the art, various changes, modifications, replacements and variations of the embodiments can be made without departing from the principles and spirits of the application, and still fall within the protection scope of the application.

Claims

1. An application of a zirconium-based amorphous metal-organic framework material, Zr-aMOF, characterized in that, The application of the zirconium-based amorphous metal-organic framework material Zr-aMOF in high-performance liquid chromatography separation; the zirconium-based amorphous metal-organic framework material Zr-aMOF is used as a stationary phase in a high-performance liquid chromatography column, and the Zr-aMOF material is a dispersible micron-sized microsphere with a size range of 2-4 μm. The preparation process of Zr-aMOF is as follows: a ligand precursor and a zirconium salt with a molar ratio of 1-4:1-1.2 are dissolved in N,N-dimethylformamide, and hydrochloric acid and ultrapure water are added at the same time. After the resulting suspension is mixed, it is heated to react at 120-220℃. After the reaction, it is separated by centrifugation to obtain the product. The zirconium salt includes zirconium tetrachloride and / or zirconium oxychloride octahydrate; The volume ratio of hydrochloric acid to water and N,N-dimethylformamide is 0.3–1.0 : 0.2–2.0 : 5–20, and 1.2–5 mL of N,N-dimethylformamide is used per 1 mmol of terephthalonitrile; The ligand precursors are terephthalonitrile, dimethyl terephthalate, terephthalamide, and their derivatives.

2. A chiral chromatographic column, characterized in that, The chiral stationary phase of the chiral chromatographic column comprises zirconium-based amorphous metal-organic framework material Zr-aMOF and polysaccharide derivatives. The preparation process of Zr-aMOF is as follows: A ligand precursor and a zirconium salt in a molar ratio of 1–4:1–1.2 were dissolved in N,N-dimethylformamide, and hydrochloric acid and ultrapure water were added simultaneously. The resulting suspension was mixed and then heated at 120–220 °C. The product was obtained by centrifugation after the reaction. The zirconium salt includes zirconium tetrachloride and / or zirconium oxychloride octahydrate; The volume ratio of hydrochloric acid to water and N,N-dimethylformamide is 0.3–1.0 : 0.2–2.0 : 5–20, and 1.2–5 mL of N,N-dimethylformamide is used per 1 mmol of terephthalonitrile; The ligand precursors are terephthalonitrile, dimethyl terephthalate, terephthalamide, and their derivatives.

3. The chiral chromatographic column as described in claim 2, characterized in that, The mass ratio of polysaccharide derivatives to zirconium-based amorphous metal-organic framework material Zr-aMOF is 1–0.8:4–12.

4. The chiral chromatographic column as described in claim 3, characterized in that, The polysaccharide derivatives include cellulose-tris-(3,5-dimethylphenylcarbamate), cellulose-tris-(4-methylbenzoate), amylose-tris-(3,5-dimethylphenylcarbamate), and amylose-tris-((S)-α-methylphenylcarbamate).

5. The method for preparing a chiral chromatographic column according to any one of claims 3-4, characterized in that, The preparation method includes the following steps: take zirconium-based amorphous metal-organic framework material Zr-aMOF and polysaccharide derivative composite material, add solvent, disperse fully, pour into homogenizer, seal well, use methanol as push liquid, pressurize and push the composite material suspension into stainless steel chromatographic column tube, and pressurize to obtain chiral chromatographic column.

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