UiO-66 (Zr) material as well as room-temperature preparation method and application thereof

Abstract

The invention belongs to the technical field of metal organic framework materials, and particularly relates to a UiO-66 (Zr) material as well as a room-temperature preparation method and application thereof. According to the preparation method provided by the invention, the UiO-66 (Zr) material can be efficiently synthesized at room temperature through the specific raw material dosage and the catalyst, the high-temperature condition and the long-time reaction process in the traditional method are avoided, and the energy consumption and the production cost are reduced. Meanwhile, the preparation method provided by the invention is simple to operate, large-scale production is easy to realize, and powerful support is provided for wide application of UiO-66 (Zr). The UiO-66 (Zr) material provided by the invention can catalyze oxidative desulfurization of fuel oil, and has excellent catalytic activity.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal organic framework materials, and in particular relates to a UiO-66 (Zr) material and a room temperature preparation method and application thereof. Background Art

[0002] As a metal-organic framework material, UiO-66(Zr) has potential applications in multiple fields due to its highly ordered pore structure and excellent chemical stability. However, the traditional preparation method of UiO-66(Zr) material usually requires long-term reaction (several hours or even days) at high temperature (100-150°C), which not only has an adverse effect on the material structure and performance, but also increases costs and reduces production efficiency, making it difficult to meet the large market demand for UiO-66(Zr) materials.

[0003] Later, researchers synthesized UiO-66(Zr) materials through a solvothermal method. Although the reaction time was relatively short, it still needed to be carried out under high temperature conditions. Summary of the Invention

[0004] The purpose of the present invention is to provide a UiO-66 (Zr) material and its room temperature preparation method and application. The preparation method provided by the present invention can efficiently synthesize the UiO-66 (Zr) material at room temperature (15-35°C).

[0005] In order to achieve the above object, the present invention provides the following technical solutions:

[0006] The present invention provides a method for preparing a UiO-66(Zr) material, comprising the following steps:

[0007] A zirconium source, an ammonium salt catalyst and an organic ligand are mixed for a coordination reaction, wherein the mass ratio of the zirconium source to the organic ligand is 125:242, the temperature of the coordination reaction is 15 to 35° C., and the holding time is 1 to 48 hours to obtain the UiO-66(Zr) material.

[0008] Preferably, the temperature of the coordination reaction is 18 to 32° C., and the insulation time is 2 to 42 hours.

[0009] Preferably, the ammonium salt catalyst is ammonium fluoride.

[0010] Preferably, the mass ratio of the ammonium salt catalyst to the organic ligand is 5 to 25:100.

[0011] Preferably, the coordination reaction is carried out under solvent conditions; the solvent includes an organic solvent and water.

[0012] Preferably, the organic solvent comprises alcohol and amide, and the volume ratio of the alcohol to the amide is 1:1.

[0013] Preferably, the ratio of the volume of the organic solvent to the mass of the organic ligand is (10-30) mL:0.25 g; and the ratio of the volume of the water to the mass of the zirconium source is 10 mL:0.484 g.

[0014] Preferably, the coordination reaction further includes post-processing the obtained product; the post-processing includes sequentially performing a first solid-liquid separation, washing, soaking in dichloromethane, a second solid-liquid separation, drying and activation.

[0015] The present invention also provides a UiO-66 (Zr) material obtained by the preparation method described in the above scheme, which has the morphology of irregular block-shaped particle aggregates, and the size of the particle aggregates is submicron to micron level.

[0016] The present invention also provides the use of the UiO-66 (Zr) material described in the above solution in the oxidative desulfurization of fuel oil.

[0017] The present invention provides a method for preparing a UiO-66(Zr) material. By using specific raw material amounts and catalysts, the method can efficiently synthesize the UiO-66(Zr) material at room temperature, avoiding the high temperatures and long reaction times required by traditional methods, thereby reducing energy consumption and production costs. Furthermore, the method is simple to operate and readily adaptable to large-scale production, providing strong support for the widespread application of UiO-66(Zr).

[0018] The present invention also provides a UiO-66(Zr) material obtained by the preparation method described above. Compared with UiO-66(Zr) materials prepared by conventional methods, the UiO-66(Zr) material prepared by the present invention exhibits irregular, blocky aggregates with sizes ranging from submicron to micron, and exhibits excellent catalytic activity in fuel oil oxidative desulfurization reactions.

[0019] The present invention also provides the use of the UiO-66(Zr) material described in the above solution in fuel oil oxidative desulfurization. The UiO-66(Zr) material provided by the present invention can catalyze fuel oil oxidative desulfurization and has excellent catalytic activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 XRD spectra of UiO-66(Zr) materials prepared in Examples 1, 4 and Comparative Example 1;

[0022] Figure 2 Nitrogen adsorption isotherms of the UiO-66(Zr) materials prepared in Examples 1 to 6 and Comparative Example 1;

[0023] Figure 3 This is a scanning electron microscope image of the UiO-66(Zr) material prepared in Example 1;

[0024] Figure 4 This is a scanning electron microscope image of the UiO-66(Zr) material prepared in Comparative Example 1;

[0025] Figure 5 Energy dispersive X-ray spectrum of the UiO-66(Zr) material prepared in Example 1;

[0026] Figure 6 Energy dispersive X-ray spectrum of the UiO-66(Zr) material prepared in Comparative Example 1;

[0027] Figure 7 This is a test chart of the oxidative desulfurization reaction activity of the UiO-66(Zr) material prepared in Example 1 and Comparative Example 1. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing a UiO-66(Zr) material, comprising the following steps:

[0029] A zirconium source, an ammonium salt catalyst and an organic ligand are mixed for a coordination reaction, wherein the mass ratio of the zirconium source to the organic ligand is 125:242, the temperature of the coordination reaction is 15 to 35° C., and the holding time is 1 to 48 hours to obtain the UiO-66(Zr) material.

[0030] In the present invention, the zirconium source can be a zirconium salt; the zirconium salt can be zirconium oxychloride; and the zirconium oxychloride can be ZrOCl2·8H2O. During the subsequent coordination reaction, zirconium acts as a metal center and coordinates with the organic ligand. In the present invention, the ammonium salt catalyst can be ammonium fluoride.

[0031] In the present invention, the organic ligand may be terephthalic acid or 2-aminoterephthalic acid.

[0032] In the present invention, the mass ratio of the ammonium salt catalyst to the organic ligand can be 5 to 25:100, specifically 6:100, 7:100, 8:100, 9:100, 10:100, 11:100, 12:100, 13:100, 14:100, 15:100, 16:100, 17:100, 18:100, 19:100, 20:100, 21:100, 22:100, 23:100, 24:100 or 25:100.

[0033] In the present invention, the mixing may be stirring mixing; the rotation speed of the stirring mixing may be 100 to 1000 rpm, specifically 300 rpm, 500 rpm or 750 rpm.

[0034] In the present invention, the coordination reaction can be carried out under solvent conditions; the solvent can include an organic solvent and water; the organic solvent can include alcohol and amide; the alcohol can be ethanol; the amide can be N,N'-dimethylformamide (DMF); the volume ratio of the alcohol and amide can be 1:1.

[0035] In the present invention, the ratio of the volume of the organic solvent to the mass of the organic ligand can be (10-30) mL:0.25 g, specifically 12 mL:0.25 g, 14 mL:0.25 g, 16 mL:0.25 g, 18 mL:0.25 g, 20 mL:0.25 g, 22 mL:0.25 g, 24 mL:0.25 g, 26 mL:0.25 g or 28 mL:0.25 g.

[0036] In the present invention, the ratio of the volume of water to the mass of the zirconium source can be 10 mL:0.484 g.

[0037] In the present invention, the temperature of the coordination reaction can be 18-32°C, specifically 21°C, 24°C or 27°C, and the insulation time can be 2-42h, specifically 5h, 8h, 12h, 18h, 25h, 30h, 35h or 40h.

[0038] In the present invention, the coordination reaction may further include post-processing the obtained product; the post-processing may include sequentially performing a first solid-liquid separation, washing, soaking in dichloromethane, a second solid-liquid separation, drying and activation.

[0039] In the present invention, the first solid-liquid separation can be centrifugation; the washing can be alcohol washing; the alcohol used for the alcohol washing can be ethanol; the temperature of the ethanol can be 30-70°C; the washing time can be 3 hours; the soaking time can be 6 hours; the number of soaking can be more than 2 times; the second solid-liquid separation can be centrifugation; the drying temperature can be 70°C, and the insulation time can be 24 hours; the activation temperature can be 150°C, the vacuum degree can be 133-1330Pa, specifically 530Pa or 1000Pa, and the insulation time can be 24 hours.

[0040] The present invention removes organic molecules adsorbed in the pores of the UiO-66(Zr) material during the preparation process through activation, which is beneficial to improving the adsorption performance of the material.

[0041] The present invention also provides a UiO-66 (Zr) material obtained by the preparation method described in the above scheme, which has the morphology of irregular block-shaped particle aggregates, and the size of the particle aggregates is submicron to micron level.

[0042] Compared with the UiO-66(Zr) material prepared by the traditional method, the UiO-66(Zr) material prepared by the present invention exhibits excellent catalytic activity in the fuel oxidation desulfurization reaction.

[0043] The present invention also provides the use of the UiO-66 (Zr) material described in the above solution in the oxidative desulfurization of fuel oil.

[0044] In the present invention, the application method may include the following steps: mixing fuel oil, nitrile, oxidant and the UiO-66(Zr) material to perform an oxidative desulfurization reaction.

[0045] In the present invention, the fuel may include n-octane and dibenzothiophene (DBT); and the sulfur content of the fuel may be 1000 ppm.

[0046] In the present invention, the nitrile may be acetonitrile; and the volume ratio of the nitrile to the fuel may be 2:3.

[0047] In the present invention, the ratio of the volume of the fuel to the mass of the UiO-66(Zr) material may be 7.5 mL:20 mg.

[0048] In the present invention, the oxidant may be hydrogen peroxide; the concentration of the hydrogen peroxide may be 30 wt %; and the volume ratio of the fuel oil to the oxidant may be 75:1.

[0049] In the present invention, the oxidative desulfurization reaction can be carried out in a water bath with stirring; the temperature of the oxidative desulfurization reaction can be 60° C., and the holding time can be 30 minutes.

[0050] The UiO-66(Zr) material provided by the present invention can catalyze the oxidative desulfurization of fuel oil and has excellent catalytic activity.

[0051] In order to further illustrate the present invention, the scheme of the present invention is described in detail below with reference to the accompanying drawings and embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0052] Example 1

[0053] (1) In a flask, dissolve 0.25 g of terephthalic acid in a 30 mL mixture of ethanol and N,N'-dimethylformamide (1:1 volume ratio) to obtain a terephthalic acid solution. In a separate flask, dissolve ZrOCl2·8H2O (0.484 g, 1.5 mmol) in 10 mL of water and add 12.5 mg of ammonium fluoride to obtain a clear solution.

[0054] (2) The terephthalic acid solution and the transparent solution were stirred and mixed at room temperature for 48 hours, and then centrifuged to obtain UiO-66(Zr) powder.

[0055] (3) The UiO-66(Zr) powder was washed with ethanol at 70°C for 3 h, then soaked in dichloromethane twice and separated, dried in an oven at 70°C for 24 h, and then vacuum activated at 150°C and 530 Pa for 24 h to obtain the UiO-66(Zr) material, a white powder, denoted as 5% NH4F-UiO-66(Zr)-48h (5% represents that the amount of ammonium fluoride added is 5% of the mass of terephthalic acid, and 48h represents 48h of reaction at room temperature).

[0056] Example 2

[0057] (1) In a flask, dissolve 0.25 g of terephthalic acid in 16 mL of a mixed solvent of ethanol and N,N'-dimethylformamide (1:1 by volume) to obtain a terephthalic acid solution. In a separate flask, dissolve ZrOCl2·8H2O (0.484 g, 1.5 mmol) in 10 mL of water and add 25 mg of ammonium fluoride to obtain a clear solution.

[0058] (2) The terephthalic acid solution and the transparent solution were stirred and mixed at room temperature for 24 hours, and then centrifuged to obtain UiO-66(Zr) powder.

[0059] (3) The UiO-66(Zr) powder was washed with ethanol at 70°C for 3 h, then soaked in dichloromethane twice and separated, dried in an oven at 70°C for 24 h, and then vacuum activated at 150°C and 530 Pa for 24 h to obtain the UiO-66(Zr) material, a white powder, recorded as 10% NH4F-UiO-66(Zr)-24h.

[0060] Example 3

[0061] (1) In a flask, dissolve 0.25 g of terephthalic acid in 16 mL of a mixed solvent of ethanol and N,N'-dimethylformamide (1:1 by volume) to obtain a terephthalic acid solution. In a separate flask, dissolve ZrOCl2·8H2O (0.484 g, 1.5 mmol) in 10 mL of water and add 50 mg of ammonium fluoride to obtain a clear solution.

[0062] (2) The terephthalic acid solution and the transparent solution were stirred and mixed at room temperature for 1 hour, and then centrifuged to obtain UiO-66(Zr) powder.

[0063] (3) The UiO-66(Zr) powder was washed with ethanol at 70°C for 3 h, then soaked in dichloromethane twice and separated, dried in an oven at 70°C for 24 h, and then vacuum activated at 150°C and 530 Pa for 24 h to obtain the UiO-66(Zr) material, a white powder, recorded as 20% NH4F-UiO-66(Zr)-1h.

[0064] Example 4

[0065] (1) In a flask, dissolve 0.25 g of terephthalic acid in 16 mL of a mixed solvent of ethanol and N,N'-dimethylformamide (1:1 by volume) to obtain a terephthalic acid solution. In a separate flask, dissolve ZrOCl2·8H2O (0.484 g, 1.5 mmol) in 10 mL of water and add 25 mg of ammonium fluoride to obtain a clear solution.

[0066] (2) The terephthalic acid solution and the transparent solution were stirred and mixed at room temperature for 12 hours, and then centrifuged to obtain UiO-66(Zr) powder.

[0067] (3) The UiO-66(Zr) powder was washed with ethanol at 70°C for 3 h, then soaked in dichloromethane twice and separated, dried in an oven at 70°C for 24 h, and then vacuum activated at 150°C and 530 Pa for 24 h to obtain the UiO-66(Zr) material, a white powder, recorded as 10% NH4F-UiO-66(Zr)-12h.

[0068] Example 5

[0069] (1) In a flask, dissolve 0.25 g of terephthalic acid in 16 mL of a mixed solvent of ethanol and N,N'-dimethylformamide (1:1 by volume) to obtain a terephthalic acid solution. In a separate flask, dissolve ZrOCl2·8H2O (0.484 g, 1.5 mmol) in 10 mL of water and add 25 mg of ammonium fluoride to obtain a clear solution.

[0070] (2) The terephthalic acid solution and the transparent solution were stirred and mixed at room temperature for 1 hour, and then centrifuged to obtain UiO-66(Zr) powder.

[0071] (3) The UiO-66(Zr) powder was washed in ethanol at 50°C for 3 h, then soaked in dichloromethane twice and separated, dried in an oven at 70°C for 24 h, and then vacuum activated at 150°C and 1330 Pa for 24 h to obtain the UiO-66(Zr) material, a white powder, recorded as 10% NH4F-UiO-66(Zr)-1h.

[0072] Example 6

[0073] (1) In a flask, dissolve 0.25 g of 2-aminoterephthalic acid in a 30 mL mixture of ethanol and N,N'-dimethylformamide (1:1 volume ratio) to obtain a 2-aminoterephthalic acid solution. In a separate flask, dissolve ZrOCl2·8H2O (0.484 g, 1.5 mmol) in 10 mL of water and add 25 mg of ammonium fluoride to obtain a clear solution.

[0074] (2) The 2-aminoterephthalic acid solution and the transparent solution were stirred and mixed at room temperature for 2 h, and then centrifuged to obtain UiO-66(Zr) powder.

[0075] (3) The UiO-66(Zr) powder was washed with ethanol at 30°C for 3 h, then soaked in dichloromethane twice and separated, dried in an oven at 70°C for 24 h, and then vacuum activated at 150°C and 133 Pa for 24 h to obtain the UiO-66(Zr) material, a white powder, recorded as 10% NH4F-NH2-UiO-66(Zr)-2h.

[0076] Comparative Example 1 Traditional Solvothermal Method

[0077] (1) ZrCl4 (1.5 mmol, 349 mg) and terephthalic acid ligand (BDC, 1.5 mmol, 249 mg) were added to a polytetrafluoroethylene-lined stainless steel autoclave (capacity 100 mL), and DMF (60 mL) was added to the stainless steel autoclave.

[0078] (2) The stainless steel autoclave was sealed and heated in an oven to 120° C. for 24 h. The autoclave was then removed from the oven and cooled to room temperature to obtain a reaction mixture.

[0079] (3) The reaction mixture was centrifuged at 5000 rpm for 5 min, then washed with 70°C ethanol for 3 h. The resulting white powder was kept at 150°C and 530 Pa in a vacuum chamber for 24 h to obtain UiO-66(Zr) material, which was designated as UiO-66(Zr)-Solvent.

[0080] Test Example 1

[0081] The UiO-66(Zr) materials prepared in Examples 1, 4 and Comparative Example 1 were subjected to XRD tests. The results are as follows: Figure 1 As shown. Figure 1 It can be seen that the UiO-66(Zr) material prepared in the present invention has a typical diffraction peak of UiO-66(Zr) and a high resolution, indicating good crystallinity.

[0082] Test Example 2

[0083] The nitrogen adsorption isotherm test was performed on the UiO-66(Zr) materials prepared in Examples 1 to 6 and Comparative Example 1. The results are as follows: Figure 2 shown.

[0084] according to Figure 2 It can be seen that the UiO-66(Zr) material prepared by the present invention exhibits the characteristics of a typical type I adsorption isotherm, indicating that it is a microporous material and has a lower specific surface area than the UiO-66(Zr) material prepared by the traditional solvothermal method; at the same time, with the increase of the amount of NH4F added, the specific surface area of ​​the UiO-66(Zr) material decreases. This is because some fluoride ions in the structure replace terephthalic acid and zirconium coordination, forming a large number of defect sites, which are the active centers of most catalytic reactions.

[0085] Test Example 3

[0086] The structure characterization test of the UiO-66(Zr) material prepared in Example 1 was carried out by observing it under a scanning electron microscope. The results are as follows: Figure 3 shown.

[0087] according to Figure 3It can be seen that the morphology of the UiO-66(Zr) material prepared in the present invention is an aggregate of irregular block particles with sizes ranging from submicron to micron, and the particle surface has slight undulations, which is attributed to the partial substitution of terephthalic acid by fluoride ions for the coordination of zirconium, forming a large number of defect sites.

[0088] Test Example 4

[0089] The structure characterization test of the UiO-66(Zr) material prepared in Comparative Example 1 was carried out by observing it under a scanning electron microscope. Figure 4 shown.

[0090] according to Figure 4 It can be seen that the morphology of the UiO-66(Zr) material prepared by the traditional solvothermal method is nanoscale spherical particles, which form submicron to micron-sized aggregates through aggregation, and fine particle stacking texture can be seen on the surface.

[0091] Test Example 5

[0092] The UiO-66(Zr) material prepared in Example 1 was subjected to energy dispersive X-ray spectroscopy test, and the results were as follows: Figure 5 shown.

[0093] according to Figure 5 It can be seen that the mass proportions of C, O, Zr and F elements in UiO-66(Zr) material are 57.5%, 25.3%, 13.8% and 2.4% respectively, and it also contains a small amount of Cl element.

[0094] Test Example 6

[0095] The UiO-66(Zr) material prepared in Comparative Example 1 was subjected to energy dispersive X-ray spectroscopy test, and the results were as follows: Figure 6 shown.

[0096] according to Figure 6 It can be seen that the mass proportions of C, O and Zr elements in UiO-66(Zr) material are 55.8%, 24.6% and 19.6% respectively.

[0097] Test Example 7

[0098] The UiO-66(Zr) materials prepared in Example 1 and Comparative Example 1 were subjected to an oxidative desulfurization activity test. The test conditions were as follows: 1.02 g of dibenzothiophene (DBT) was added to 250 mL of n-octane to prepare a model oil with a sulfur content of 1000 ppm; 7.5 mL of the model oil, 5 mL of acetonitrile, and 20 mg of the catalyst (material of Example 1 or Comparative Example 1) were added to the reaction flask, stirred in a water bath at 60° C. for 30 min, and then 100 μL of 30 wt% hydrogen peroxide was added. The reaction was started, and 0.5 mL of the model oil was taken out every 20 min. The product was analyzed by gas chromatography. The results are as follows: Figure 7 shown.

[0099] according to Figure 7 It can be seen that the oxidative desulfurization reaction activity of 5% NH4F-UiO-66(Zr)-48h synthesized at room temperature is significantly higher than that of UiO-66(Zr)-Solvent synthesized by the traditional solvothermal method.

[0100] It can be seen from the above examples that the UiO-66(Zr) material obtained by the preparation method provided by the present invention has high crystallinity, many active sites and high catalytic activity.

[0101] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing UiO-66(Zr) material, characterized in that: The following steps are involved: A zirconium source, an ammonium salt catalyst and an organic ligand are mixed for a coordination reaction, wherein the mass ratio of the zirconium source to the organic ligand is 125:242, the temperature of the coordination reaction is 15 to 35° C., and the holding time is 1 to 48 hours to obtain the UiO-66(Zr) material.

2. The preparation method according to claim 1, characterized in that The temperature of the coordination reaction is 18-32° C., and the insulation time is 2-42 hours.

3. The preparation method according to claim 1, characterized in that The ammonium salt catalyst is ammonium fluoride.

4. The preparation method according to claim 1 or 3, characterized in that The mass ratio of the ammonium salt catalyst to the organic ligand is 5 to 25:

100.

5. The preparation method according to claim 1, characterized in that The coordination reaction is carried out under solvent conditions; the solvent includes an organic solvent and water.

6. The preparation method according to claim 5, characterized in that The organic solvent includes alcohol and amide, and the volume ratio of the alcohol to the amide is 1:

1.

7. The preparation method according to claim 5 or 6, characterized in that: The ratio of the volume of the organic solvent to the mass of the organic ligand is (10-30) mL:0.25 g; and the ratio of the volume of the water to the mass of the zirconium source is 10 mL:0.484 g.

8. The preparation method according to claim 1, characterized in that After the coordination reaction, the obtained product is subjected to post-processing; the post-processing includes sequentially performing first solid-liquid separation, washing, soaking in dichloromethane, second solid-liquid separation, drying and activation.

9. The UiO-66(Zr) material obtained by the preparation method according to any one of claims 1 to 8 has the morphology of irregular block-shaped particle aggregates, and the size of the particle aggregates is submicron to micron level.

10. Use of the UiO-66(Zr) material according to claim 9 in fuel oxidation desulfurization.

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