A zirconium-based molybdate oxidative desulfurization catalyst and its preparation method and application

Abstract

The present invention relates to the technical field of oil oxidative desulfurization, and in particular to a zirconium-based molybdate oxidative desulfurization catalyst and its preparation method and application, firstly, the carrier PCN-777 is functionalized to realize its conversion from hydrophilicity to hydrophobicity, secondly, organic cations and polyoxometalate anions are combined to prepare an active component, and then the active component is loaded onto a carrier to obtain a supported catalyst, using acetonitrile as an extractant and hydrogen peroxide as an oxidant, and oxidative removal of thiophene-containing sulfur compounds in oil products is carried out, PCN-777 is a zirconium-based metal organic framework, which has a large specific surface area, a large pore volume and good stability. In addition, the Zr-O clusters in PCN-777 show catalytic activity, which is conducive to ODS reaction. The catalyst prepared by the present invention can reach a 100% removal rate of dibenzothiophene within 50min, and the activity is not significantly reduced after 29 cycles of regeneration and its stability is still maintained.

Description

Technical Field

[0001] The present invention relates to the technical field of oil oxidation desulfurization, and in particular to a zirconium-based molybdate oxidation desulfurization catalyst, a preparation method and application thereof. Background Art

[0002] As countries around the world are increasingly stringent in restricting the sulfur content in fuel, some places have even explicitly announced that the sulfur content should not exceed 10ppm. Therefore, in order to adapt to this rule, various environmental protection technologies have emerged. However, the transportation and power industries are still unable to stop using fuel. In this case, they can only obtain further clean energy through fuel desulfurization. At present, the main desulfurization methods at home and abroad are hydrodesulfurization and non-hydrodesulfurization technology. Hydrodesulfurization (HDS) is currently the most widely used industrial desulfurization technology. However, the reaction and operating conditions of this technology are harsh, and it will cause high energy consumption. Among non-hydrodesulfurization, oxidative desulfurization (ODS) can not only remove difficult-to-degrade sulfur compounds with zero hydrogen consumption, but also obtain ultra-low sulfur fuel oil at a lower cost under mild conditions.

[0003] Polyoxometalates (POMs), a member of the metal oxycluster anion family, are formed by the condensation of various metal oxyanions (Mo, W, V, P), and have made significant progress in the field of ODS. In addition to Keggin POMs, there are also C 2V The symmetrical Lindqvist POMs also possess reversible multi-electron redox capabilities and high catalytic efficiency.

[0004] Ionic liquids (ILs), green solvents with low melting points and high thermal stability, are molten salts composed of organic cations and organic / inorganic anions. They have also been extensively studied in the field of oxidative desulfurization. Currently, ILs are used not only as solvents or reaction media but also as catalysts for ODS reactions. Metal oxide ionic liquids (POM-ILs) combine the structural and property characteristics of ionic liquids and polyoxometalates, offering a broader scope for their application in catalysis.

[0005] The industrial application of supported catalysts in oxidative desulfurization still faces many challenges. Currently, the key and difficult areas of oxidative desulfurization are how to design and synthesize new supported catalysts that can both increase the number of active sites and improve catalyst recovery, and how to manipulate their structural composition to enhance catalyst stability and achieve rapid desulfurization. Summary of the Invention

[0006] In view of the deficiencies of the above-mentioned prior art, the purpose of the present invention is to provide a zirconium-based molybdate oxidative desulfurization catalyst and its preparation method and application. The present invention functionalizes the carrier PCN-777 to achieve its transformation from hydrophilicity to hydrophobicity, and then combines organic cations and polymetallic acid salt anions to prepare active components, which are then loaded onto the carrier to obtain a supported catalyst.

[0007] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0008] A method for preparing a zirconium-based molybdate oxidative desulfurization catalyst comprises the following steps:

[0009] (1) zirconium oxychloride octahydrate, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, N,N-diethylformamide and trifluoroacetic acid are mixed and subjected to a hydrothermal reaction to obtain PCN-777;

[0010] (2) mixing the PCN-777 obtained in step (1), tetra-tert-butylbenzoic acid, and N,N-dimethylformamide to obtain tBu-PCN-777;

[0011] (3) Add dodecylpyridinium chloride and ammonium molybdate tetrahydrate into water and mix them to obtain [C 12 Py]3(NH4)3Mo7O 24 ;

[0012] (4) The [C 12 Py]3(NH4)3Mo7O 24 The supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

[0013] Preferably, in step (1), the mass volume ratio of zirconium oxychloride octahydrate, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, N,N-diethylformamide and trifluoroacetic acid is 1.3-1.5 g:0.3-0.4 g:45-50 mL:2-3 mL, and the reaction is carried out in a polytetrafluoroethylene reactor at 120-130 ° C for 12-13 hours.

[0014] Preferably, in step (1), the obtained sample is filtered, washed three times with DMF and acetone respectively, and then dried to obtain white powder PCN-777.

[0015] Preferably, in step (2), the mass volume ratio of PCN-777, tetra-tert-butylbenzoic acid and N,N-dimethylformamide is 0.55-0.65 g:2.2-2.6 g:45-50 mL, which are mixed in a three-necked flask and ultrasonically dispersed, and stirred at 100-110° C. for 14-16 h.

[0016] Preferably, in step (2), the obtained sample is filtered, washed three times with DMF and acetone respectively, and then dried to obtain white powder tBu-PCN-777.

[0017] Preferably, in step (3), the molar ratio of dodecylpyridinium chloride to ammonium molybdate tetrahydrate is 1:3, and the mixture is stirred in deionized water at room temperature for 22 to 26 hours.

[0018] Preferably, the raw materials in step (3) are mixed and stirred, filtered, washed with deionized water three times and then dried to obtain a white powder [C 12 Py]3(NH4)3Mo7O 24 .

[0019] Preferably, the [C 12 Py]3(NH4)3Mo7O 24 Dissolved in dimethyl sulfoxide solution, then impregnated in tBu-PCN-777 by wet impregnation method, and dried to obtain supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

[0020] Another object of the present invention is to protect a zirconium-based molybdate oxidative desulfurization catalyst prepared by any of the preparation methods described above, wherein the catalyst has the molecular formula shown in formula (1):

[0021]

[0022] The third object of the present invention is to protect the use of the above-mentioned zirconium-based molybdate oxidative desulfurization catalyst in the oxidative desulfurization of oil products.

[0023] The application method is: simulated fuel, oxidant and the above catalyst are mixed and reacted, the oil is taken out at regular intervals, acetonitrile is used as an extractant, and the layers are separated after standing. The upper layer solution obtained is the desulfurized oil.

[0024] Preferably, in the method of fuel oxidation desulfurization, the volume ratio of the oxidant to the fuel is 0.0055:1, the amount ratio of the oxidant to the sulfur content in the fuel is 5:1, the amount ratio of the catalyst to the fuel is 0.005g:1mL, and the sulfur content in the fuel is 500ppm.

[0025] Preferably, in the fuel oil oxidation desulfurization method, the oxidant is a hydrogen peroxide solution containing 25%-35% H2O2, the reaction temperature is 40-70°C, and the mixing reaction time is 50 minutes.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The present invention transfers electrons to the active component [C 12 Py]3(NH4)3Mo7O 24 , leading to the formation of a narrow band gap for electron transport and a high electron density of Mo active sites, which further promotes the oxidation of DBT to DBTO2 in the model oil.

[0028] 2. The hydrophobic tBu-PCN-777 of the present invention is highly dispersible in oil, effectively avoiding the problem of insufficient catalytic effect caused by catalyst agglomeration, which significantly improves the catalytic efficiency of the catalyst.

[0029] 3. The present invention first functionalizes the carrier PCN-777 to achieve its transformation from hydrophilic to hydrophobic, and then combines organic cations and polyoxometalate anions to prepare active components, and then loads the active components onto the carrier to obtain a supported catalyst. Using acetonitrile as an extractant and hydrogen peroxide as an oxidant, thiophene-type sulfur-containing compounds in oil products are oxidized and removed. PCN-777 is a zirconium-based metal organic framework with a large specific surface area, large pore volume and good stability. In addition, the Zr-O clusters in PCN-777 show catalytic activity, which is beneficial to the ODS reaction. The catalyst prepared by the present invention can achieve a 100% removal rate of dibenzothiophene within 50 minutes, and its activity does not decrease significantly after 29 cycles of regeneration and its stability is still maintained.

[0030] 4. PCN-777, a zirconium-based MOF selected in the present invention, possesses a large specific surface area and high stability. Furthermore, the Zr-O clusters in PCN-777 possess catalytic activity, favoring the ODS reaction. Furthermore, the extended, highly conjugated ligands in the PCN-777 structure effectively promote charge separation, allowing electrons in the PCN-777 structure to be injected into the Zr clusters, giving them electron-donating capacity and thus promoting catalytic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 : are Fourier transform infrared spectra of different samples of the present invention;

[0032] Figure 2 XRD spectra of different samples of the present invention;

[0033] Figure 3XPS spectra of different samples of the present invention. DETAILED DESCRIPTION

[0034] The following is a detailed description of the preferred embodiments of the present invention with reference to the accompanying drawings.

[0035] The fuel types used in the following examples are:

[0036] The model oil is prepared by adding thiophene, dibenzothiophene and 4,6-dimethyldibenzothiophene into n-octane to prepare a 500 ppm model oil.

[0037] In a round-bottom flask equipped with a magnetic stirrer, add the catalyst to the model oil. After reaching the reaction temperature, add the oxidant. Remove the model oil at regular intervals, use acetonitrile as the extraction solvent, take the supernatant, and then use gas chromatography (GC-FID) to detect the sulfur content in the oil. Calculate the desulfurization rate:

[0038]

[0039] Example 1

[0040] A method for preparing a zirconium-based molybdate oxidative desulfurization catalyst comprises the following steps:

[0041] (1) 1.44 g zirconium oxychloride octahydrate, 0.36 g 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 48 mL DEF, and 2.4 mL trifluoroacetic acid were mixed in a polytetrafluoroethylene reactor and hydrothermally reacted at 120 °C for 12 h. The obtained sample was filtered, washed with DMF and acetone three times respectively, and then dried to obtain white powder PCN-777;

[0042] (2) 0.6 g PCN-777, 2.4 g tetra-tert-butylbenzoic acid, and 50 mL DMF were mixed in a three-necked flask and ultrasonically dispersed. The mixture was stirred at 100 °C for 15 h. The obtained sample was filtered, washed with DMF and acetone three times, and then dried to obtain a white powder tBu-PCN-777.

[0043] (3) (NH4)6Mo7O 24 ·4H2O and [C 12 Py]Cl were mixed in a molar ratio of 1:3 and stirred in deionized water at room temperature for 24 h. The resulting solution was filtered, washed with deionized water three times, and dried to obtain a white powder [C 12 Py]3(NH4)3Mo7O 24 ;

[0044] (4) [C 12 Py]3(NH4)3Mo7O 24Completely dissolved in DMSO solution, then impregnated into tBu-PCN-777 by wet impregnation method, and dried to obtain supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

[0045] Example 2

[0046] (1) 1.3 g zirconium oxychloride octahydrate, 0.3 g 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 40 mL DEF, and 2 mL trifluoroacetic acid were mixed in a polytetrafluoroethylene reactor and hydrothermally reacted at 125 °C for 12.5 h. The obtained sample was filtered, washed with DMF and acetone three times respectively, and then dried to obtain white powder PCN-777;

[0047] (2) 0.55 g PCN-777, 2.2 g tetra-tert-butylbenzoic acid, and 45 mL DMF were mixed in a three-necked flask and ultrasonically dispersed. The mixture was stirred at 105 °C for 14 h. The resulting sample was filtered, washed with DMF and acetone three times, and then dried to obtain a white powder tBu-PCN-777.

[0048] (3) (NH4)6Mo7O 24 ·4H2O and [C 12 Py]Cl were mixed in a molar ratio of 1:3 and stirred in deionized water at room temperature for 22 h. The resulting solution was filtered, washed with deionized water three times, and dried to obtain a white powder [C 12 Py]3(NH4)3Mo7O 24 ;

[0049] (4) [C 12 Py]3(NH4)3Mo7O 24 Completely dissolved in DMSO solution, then impregnated into tBu-PCN-777 by wet impregnation method, and dried to obtain supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

[0050] Example 3

[0051] (1) 1.5 g zirconium oxychloride octahydrate, 0.4 g 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 50 mL DEF, and 3 mL trifluoroacetic acid were mixed in a polytetrafluoroethylene reactor and hydrothermally reacted at 130 °C for 13 h. The obtained sample was filtered, washed with DMF and acetone three times respectively, and then dried to obtain white powder PCN-777;

[0052] (2) 0.65 g PCN-777, 2.6 g tetra-tert-butylbenzoic acid, and 48 mL DMF were mixed in a three-necked flask and ultrasonically dispersed. The mixture was stirred at 110 °C for 16 h. The resulting sample was filtered, washed with DMF and acetone three times, and then dried to obtain a white powder tBu-PCN-777.

[0053] (3) (NH4)6Mo7O 24 ·4H2O and [C 12 Py]Cl were mixed in a molar ratio of 1:3 and stirred in deionized water at room temperature for 26 h. The resulting solution was filtered, washed with deionized water three times, and dried to obtain a white powder [C 12 Py]3(NH4)3Mo7O 24 ;

[0054] (4) [C 12 Py]3(NH4)3Mo7O 24 Completely dissolved in DMSO solution, then impregnated into tBu-PCN-777 by wet impregnation method, and dried to obtain supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

[0055] Comparative Example 1

[0056] A method for preparing a zirconium-based molybdate oxidative desulfurization catalyst comprises the following steps:

[0057] (1) 1.44 g zirconium oxychloride octahydrate, 0.36 g 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, 48 mL DEF, and 2.4 mL trifluoroacetic acid were mixed in a polytetrafluoroethylene reactor and hydrothermally reacted at 120 °C for 12 h. The obtained sample was filtered, washed with DMF and acetone three times respectively, and then dried to obtain white powder PCN-777;

[0058] (2) (NH4)6Mo7O 24 ·4H2O and [C 12 Py]Cl were mixed in a molar ratio of 1:3 and stirred in deionized water at room temperature for 24 h. The resulting solution was filtered, washed with deionized water three times, and dried to obtain a white powder [C 12 Py]3(NH4)3Mo7O 24 ;

[0059] (3) [C 12 Py]3(NH4)3Mo7O 24Completely dissolved in DMSO solution, then impregnated into PCN-777 by wet impregnation method, and dried to obtain supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / PCN-777

[0060] Application Examples

[0061] Model oil preparation: Add 1g of dibenzothiophene (DBT) and 0.7g of tetradecane to 500mL of n-octane and sonicate for 30 minutes to create a 500ppm simulated sulfur fuel. Add 0.046g of 4,6-dimethyldibenzothiophene (4,6-DMDBT) and 0.0367mL of tetradecane to 20mL of n-octane and sonicate for 30 minutes to create a 500ppm simulated sulfur fuel. Add 0.0184g of thiophene (BT) and 0.0367mL of tetradecane to 20mL of n-octane and sonicate for 30 minutes to create a 500ppm simulated sulfur fuel.

[0062] Application Example 1

[0063] The model oil was heated to 40° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were then added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 92.69%.

[0064] Application Example 2

[0065] The model oil was heated to 50° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were then added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 97.66%.

[0066] Application Example 3

[0067] The model oil was heated to 60° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were then added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0068] Application Example 4

[0069] The model oil was heated to 70° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were then added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 97.74%.

[0070] Application Example 5

[0071] The simulated oil was heated to 60° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 44 μL of H 2 O 2 were then added. The mixture was reacted for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 89.97%.

[0072] Application Example 6

[0073] The simulated oil was heated to 60° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were then added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0074] Application Example 7

[0075] The simulated oil was heated to 60° C. and maintained for 20 minutes. Then, 0.06 g of the catalyst of Example 1 and 66 μL of H 2 O 2 were added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0076] Application Example 8

[0077] The simulated oil was heated to 60° C. and maintained for 20 minutes. 0.06 g of the catalyst of Example 1 and 77 μL of H 2 O 2 were then added. The mixture was reacted for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 100%.

[0078] Application Example 9

[0079] The simulated oil (BT) was heated to 60° C. and maintained for 20 minutes. Then, 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were added. The mixture was reacted for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 89.24%.

[0080] Application Example 10

[0081] The simulated oil (4,6-DMDBT) was heated to 60° C. and maintained for 20 minutes. Then, 0.06 g of the catalyst of Example 1 and 55 μL of H 2 O 2 were added. The mixture was reacted for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 89.69%.

[0082] Comparative Application Example 1

[0083] The model oil was heated to 60° C. and maintained for 20 minutes. Then, 0.06 g of the catalyst prepared in Comparative Example 1 and 55 μL of H 2 O 2 were added. The reaction was continued for 50 minutes. The sulfur content was measured and the desulfurization rate was calculated to be 80.82%.

[0084] Table 1 shows the test results of the application examples and comparative examples. As can be seen from Table 1, the optimal reaction temperature selected for Application Examples 1, 2, 3, and 4 is 60°C. In combination with Application Examples 5, 6, 7, and 8, the optimal amount of oxidant required for the reaction is 55 μL, that is, the molar ratio of the oxidant to the sulfur content of the fuel is 5. In combination with Application Examples 9 and 10, a high removal rate is also achieved for BT, 4,6-DMDBT, which is relatively difficult to remove by oxidative desulfurization. However, the catalyst prepared in Comparative Example 1 directly using PCN-777 as a carrier is tested under the same test conditions as Application Example 3, and its desulfurization rate is only 80.82%, which is far lower than that of Application Examples 1-10. This is mainly due to the low dispersibility of the hydrophilic PCN-777 carrier in the oil, which makes the catalyst easily agglomerated, resulting in reduced catalytic efficiency.

[0085] Table 1 Test results of examples and comparative examples

[0086]

[0087]

[0088] Table 2 Cycling test when the model oil is DBT

[0089] Number of cycles Desulfurization rate (%) Number of cycles Desulfurization rate (%) Number of cycles Desulfurization rate (%) 1 100 10 100 19 96.94 2 100 11 100 20 96.84 3 100 12 100 21 96.77 4 100 13 99.16 22 96.32 5 100 14 98.89 23 96.19 6 100 15 98.25 24 94.32 7 100 16 97.94 25 95.35 8 100 17 97.33 26 95.42 9 100 18 97.23

[0090] The reacted catalyst was filtered and dried to remove the water carried by the H₂O₂. Fresh oil and H₂O₂ were then added. A cycle experiment was conducted. The desulfurization rate did not significantly decrease after 26 cycles. The desulfurization rates are shown in Table 2.

[0091] Analysis of test results

[0092] Figure 1 The Fourier transform infrared spectra of different samples show the absorption peaks of each sample, which proves that each sample has been successfully synthesized. The characteristic peaks of Mo-O-Mo are located at 574 and 640 cm -1 At 885, 917 and 943 cm -1 The characteristic peak at 1486 cm is attributed to the stretching mode of Mo=O. -1 The characteristic peak at [C 12 The presence of pyridine in the infrared spectrum of Py]3Cl is due to the presence of pyridine at 782 and 1583 cm -1 At the 30° point, the characteristic peaks caused by the out-of-plane bending vibration of aromatic hydrogen and the in-plane ring deformation vibration of pyridine molecules can be clearly seen. 12 Py]3(NH4)3Mo7O 24The presence of POM and IL groups can be seen in the spectrum of . The difference is that the characteristic peaks belonging to Mo-O-Mo are shifted to 557 and 671 cm -1 The characteristic peak originally belonging to Mo=O is at 885cm -1 The spectrum of PCN-777 shows that the peaks at 659 and 775 cm -1 The characteristic peak at is related to the stretching vibration of Zr-O. The typical characteristic peak of PCN-777 is the absorption peak of triazine at 1517 cm -1 Visible, 1016cm -1 The characteristic peak at [C 12 Py]3(NH4)3Mo7O 24 In the spectrum of / tBu-PCN-777-35%, we can see [C 12 Py]3(NH4)3Mo7O 24 and characteristic peaks of tBu-PCN-777.

[0093] Figure 2 The XRD spectra of different samples show the diffraction peaks of each sample, which proves that each sample has been successfully synthesized. The principle analysis is: (NH4)6Mo7O 24 The diffraction peak of 4H2O is consistent with the standard (NH4)6Mo7O 24 4H2O (JCPDS: 27-1013). In addition, [C 12 Py]3(NH4)3Mo7O 24 and (NH4)6Mo7O 24 The 4H2O monoclinic phase also has a large consistency, proving that the introduction of ionic liquids has no effect on the crystallization of the sample. The strong diffraction peaks of tBu-PCN-777 appear at 5.4°, 5.6°, and 6.4°, which correspond well to the peak positions of the simulated PCN-777. In addition, [C 12 Py]3(NH4)3Mo7O 24 The peak positions of the catalyst at 9.14°, 10° and 11.86° for / tBu-PCN-777-35% are consistent with those of [C 12 Py]3(NH4)3Mo7O 24 Same, similar to [C 12 Py]3(NH4)3Mo7O 24 The diffraction peak also appears in the range of 17.26 to 33.52°.

[0094] Figure 3 The XPS spectrum of the catalyst shows the elemental composition and chemical state of the catalyst.12 Py]3(NH4)3Mo7O 24 The measured spectrum of / tBu-PCN-777-35% shows the signals of C, N, O, Zr and Mo, which is consistent with the expected results. 2 ), CN / C=N and C=O bonds represent three peaks in the C1s spectrum, located at 284.80eV, 286.20eV and 288.81eV respectively. The two peaks at 398.31eV and 401.90eV are attributed to C=NC and CN bonds. The peaks at 530.52eV, 531.94eV and 533.67eV are attributed to Zr-O, C=O and CO bonds. The binding energies of 182.75eV and 185.10eV are respectively for Zr 4+ Oxidized Zr 3d 5 / 2 and Zr 3d 3 / 2 The peaks at 232.56eV and 235.72eV in the Mo 3d spectrum are Mo 6+ 3d 5 / 2 and Mo 6+ 3d 3 / 2 .

[0095] In summary, the present invention first functionalizes the carrier PCN-777 to achieve its transformation from hydrophilic to hydrophobic, and then combines organic cations and polyoxometalate anions to prepare active components, and then loads the active components onto the carrier to obtain a supported catalyst. Using acetonitrile as an extractant and hydrogen peroxide as an oxidant, thiophene-type sulfur-containing compounds in oil products are oxidized and removed. PCN-777 is a zirconium-based metal organic framework with a large specific surface area, a large pore volume and good stability. In addition, the Zr-O clusters in PCN-777 show catalytic activity, which is beneficial to the ODS reaction. The catalyst prepared by the present invention can achieve a 100% removal rate of dibenzothiophene within 50 minutes, and its activity does not decrease significantly after 29 cycles of regeneration and its stability is still maintained.

[0096] Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if such changes and modifications fall within the scope of the claims and their equivalents, the present invention is intended to include such changes and modifications.

Claims

1. A method for preparing a zirconium-based molybdate oxidative desulfurization catalyst, characterized in that: The following steps are involved: (1) Zirconium oxychloride octahydrate, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, N,N-diethylformamide and trifluoroacetic acid were mixed and subjected to hydrothermal reaction to obtain PCN-777; the mass volume ratio of zirconium oxychloride octahydrate, 2,4,6-tris(4-carboxyphenyl)-1,3,5-triazine, N,N-diethylformamide and trifluoroacetic acid was 1.3-1.5 g:0.3-0.4 g:45-50 mL:2-3 mL, and the mixture was reacted at 120-130 °C for 12-13 h in a polytetrafluoroethylene reactor; (2) PCN-777 obtained in step (1), tetra-tert-butylbenzoic acid and N,N-dimethylformamide are mixed and reacted to obtain tBu-PCN-777; PCN-777, tetra-tert-butylbenzoic acid and N,N-dimethylformamide are mixed in a three-necked flask in a mass volume ratio of 0.55-0.65 g:2.2-2.6 g:45-50 mL, and ultrasonic dispersion is performed, and stirring is carried out at 100-110° C. for 14-16 h; (3) Add dodecylpyridinium chloride and ammonium molybdate tetrahydrate into water and mix them to obtain [C 12 Py]3(NH4)3Mo7O 24 The molar ratio of dodecylpyridinium chloride and ammonium molybdate tetrahydrate was 1:3, and the mixture was stirred in deionized water at room temperature for 22 to 26 hours; (4) The [C 12 Py]3(NH4)3Mo7O 24 The supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

2. The method for preparing a zirconium-based molybdate oxidative desulfurization catalyst according to claim 1, wherein: In step (1), the obtained sample is filtered, washed three times with DMF and acetone respectively, and then dried to obtain white powder PCN-777.

3. The method for preparing a zirconium-based molybdate oxidative desulfurization catalyst according to claim 1, characterized in that: In step (2), the obtained sample is filtered, washed three times with DMF and acetone respectively, and then dried to obtain white powder tBu-PCN-777.

4. The method for preparing a zirconium-based molybdate oxidative desulfurization catalyst according to claim 1, characterized in that: The raw materials in step (3) were mixed and stirred, filtered, washed with deionized water three times and dried to obtain a white powder [C 12 Py]3(NH4)3Mo7O 24 .

5. The method for preparing a zirconium-based molybdate oxidative desulfurization catalyst according to claim 1, characterized in that: The [C 12 Py]3(NH4)3Mo7O 24 Dissolved in dimethyl sulfoxide solution, then impregnated in tBu-PCN-777 by wet impregnation method, and dried to obtain supported catalyst [C 12 Py]3(NH4)3Mo7O 24 / tBu-PCN-777.

6. A zirconium-based molybdate oxidative desulfurization catalyst prepared by the preparation method according to any one of claims 1 to 5, characterized in that: The catalyst has the molecular formula shown in formula (1): （1）。 7. Use of the zirconium-based molybdate oxidative desulfurization catalyst according to claim 6 in the oxidative desulfurization of oil products.

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