A modified zeolite material, its preparation method and its application in benzene oxidation

Abstract

The present invention relates to a method for preparing a modified zeolite material, which method comprises: S1. placing a first conductive object and a second conductive object respectively connected to the positive electrode and the negative electrode of a DC power supply in an aqueous solution of an organic base, and electrolyzing for 1 - 10 days at a voltage of 10 - 100 V to obtain a carbon dot solution; wherein, the first conductive object is a graphite formed body; S2. stirring and mixing titanium silicalite, an iron source and the carbon dot solution at 20 - 90 °C for 1 - 12 h to obtain a mixture; S3. subjecting the mixture to a hydrothermal reaction, and then taking out the solid to obtain the modified zeolite material. The method of the present invention can prepare a modified zeolite material with excellent catalytic performance. When it is used in benzene oxidation, the conversion rate of raw materials and the selectivity of target products can be improved.

Description

Technical Field

[0001] The present invention relates to a modified zeolite material, a preparation method thereof, and an application thereof in benzene oxidation. Background Art

[0002] Nanocarbon materials refer to fine carbon particles with sizes in the nanometer range (1 - 100 nm). Similar to ordinary nanomaterials, they also have special properties such as quantum size effect, small size effect, and macroscopic quantum tunneling effect in aspects such as optics, electricity, and magnetism. In 2004, fine carbon nanoparticles with sizes less than 10 nm were first named carbon dots when purifying single-walled carbon nanotubes by electrophoresis. It is a new type of small-sized nanocarbon material. Based on this, carbon dots are expected to be applied in related fields such as energy issues, environmental protection, and photovoltaic devices.

[0003] In fields such as the selective catalytic application of hydrocarbons, molecular sieve-based porous materials are an important type of catalytic material. However, existing molecular sieve-based porous materials still need to be improved and optimized in terms of material properties, etc. Nanocarbon materials such as carbon dots also have great potential in the preparation and modification of porous materials, and it is worthy and necessary for the majority of scientific and technological workers to conduct in-depth research and industrial development to promote the technological development in fields such as the selective catalytic application of hydrocarbons. Summary of the Invention

[0004] The object of the present invention is to provide a modified zeolite material, a preparation method thereof, and an application thereof in benzene oxidation. The method of the present invention can prepare a modified zeolite material with excellent catalytic performance, and when it is used in benzene oxidation, it can improve the conversion rate of raw materials and the selectivity of target products.

[0005] To achieve the above object, in the first aspect of the present invention, a method for preparing a modified zeolite material is provided, and the method includes:

[0006] S1. A first conductive object and a second conductive object respectively connected to the positive electrode and the negative electrode of a DC power supply are placed in an aqueous solution of an organic base, and electrolyzed at a voltage of 10 - 100 V for 1 - 10 days to obtain a carbon dot solution; wherein, the first conductive object is a graphite formed body;

[0007] S2. Titanium silicalite, an iron source, and the carbon dot solution are stirred and mixed at 20 - 90 °C for 1 - 12 h to obtain a mixture;

[0008] S3. After the mixture is subjected to a hydrothermal reaction, the solid is taken out to obtain the modified zeolite material.

[0009] Optionally, in step S1, a first conductive object and a second conductive object respectively connected to the positive electrode and the negative electrode of a DC power supply are placed in an aqueous solution of an organic base, and electrolyzed at a voltage of 20 - 80 V for 2 - 8 days;

[0010] The concentration of the carbon dot solution is 1-1000 mg / L, preferably 10-500 mg / L; the concentration of the organic base in the aqueous solution of the organic base is 10-2500 mmol / L, preferably 50-1500 mmol / L.

[0011] Optionally, in step S2, the weight ratio of the titanium silicalite, the iron source and the carbon dot solution is 100:(0.5-50):(50-5000);

[0012] Preferably, the weight ratio of the titanium silicalite, the iron source and the carbon dot solution is 100:(5-25):(100-2000).

[0013] Optionally, in step S3, the conditions of the hydrothermal reaction include: the temperature is 100-200 °C and the time is 3-360 hours; preferably, the temperature is 100-180 °C and the time is 6-96 hours.

[0014] Optionally, the silicon-titanium molar ratio of the titanium silicalite is 15-150, and the titanium silicalite is microporous titanium silicalite and / or mesoporous titanium silicalite;

[0015] The microporous titanium silicalite is one or more of MFI, BEA, MOR and FAU; the mesoporous titanium silicalite is SBA-15 and / or MCM-41;

[0016] The iron source is selected from one or more of iron nitrate, iron chloride, iron sulfate, iron phosphate and iron acetate, preferably iron nitrate;

[0017] The organic base is selected from urea, quaternary ammonium base compounds, fatty amine compounds or alkanolamine compounds, or a combination of two or three of them; wherein,

[0018] The quaternary ammonium base compounds are tetraethylammonium hydroxide, tetrapropylammonium hydroxide or tetrabutylammonium hydroxide, or a combination of two or three of them;

[0019] The fatty amine compounds are ethylamine, n-butylamine, butanediamine or hexanediamine, or a combination of two or three of them;

[0020] The alkanolamine compounds are selected from monoethanolamine, diethanolamine or triethanolamine, or a combination of two or three of them.

[0021] The second aspect of the present invention provides a modified zeolite material prepared by the method provided in the first aspect of the present invention.

[0022] Optionally, the average particle size of the modified zeolite material is 20 - 600 nm, preferably 50 - 500 nm, and more preferably 100 - 300 nm; the external specific surface area accounts for 20 - 80% of the total specific surface area, preferably 30 - 60%; the mesoporous pore volume accounts for 30 - 85% of the total pore volume, preferably 40 - 70%.

[0023] Optionally, when the nitrogen constant temperature adsorption and desorption test is performed on the modified zeolite material, when P / P0 is 0.8, the desorption amount of the modified zeolite material accounts for 70 - 95% of the total desorption amount to be desorbed, preferably 80 - 90%.

[0024] Optionally, based on the dry basis weight of the modified zeolite material, the iron content in terms of iron oxide is 0.1 - 5% by weight, preferably 0.5 - 3% by weight; the titanium content in terms of titanium oxide is 0.5 - 6% by weight, preferably 1 - 3% by weight.

[0025] The third aspect of the present invention provides an application of the modified zeolite material provided in the second aspect of the present invention in the preparation of hydroquinone by benzene oxidation.

[0026] Through the above technical solution, the method of the present invention can prepare a modified zeolite material with two active centers, which is beneficial to improving the catalytic reaction performance of the modified zeolite material. When it is used in the oxidation reaction of benzene, the conversion rate of benzene and the selectivity to the target product hydroquinone can be improved.

[0027] Other features and advantages of the present invention will be described in detail in the subsequent specific implementation section. Specific Embodiments

[0028] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0029] The first aspect of the present invention provides a method for preparing a modified zeolite material, and the method includes:

[0030] S1. Place a first conductive object and a second conductive object respectively connected to the positive and negative electrodes of a DC power supply in an aqueous solution of an organic base, and electrolyze for 1 - 10 days at a voltage of 10 - 100 V to obtain a carbon dot solution; wherein, the first conductive object is a graphite formed body;

[0031] S2. Stir and mix titanium silicalite, an iron source, and the carbon dot solution at 20 - 90 °C for 1 - 12 h to obtain a mixture;

[0032] S3. After performing a hydrothermal reaction on the mixture, take out the solid to obtain the modified zeolite material.

[0033] The method of the present invention uses titanium silicalite, an iron source, and a carbon dot solution as raw materials to prepare a modified zeolite material. By adding the carbon dot solution prepared by electrolyzing graphite using an electrolyte containing an organic base during the material mixing stage of preparing the modified zeolite material, the preparation process of the modified zeolite material can be effectively regulated. The surface and / or internal defect distribution of the modified zeolite material prepared by the method of the present invention is more uniform, which is beneficial to the diffusion of reactants and products, can improve the reaction activity of the modified zeolite material, and is particularly beneficial to improving the selectivity of the target product.

[0034] In a specific embodiment of the present invention, the dosage of the aqueous solution of the organic base is not specifically limited and can be selected according to actual needs, for example, selected according to the sizes of the first conductive object and the second conductive object and the electrolysis conditions. The present invention does not limit the specific form of graphite forming, for example, it can be a graphite rod, a graphite plate, etc. In a preferred specific embodiment, the size of the first conductive object matches the size of the second conductive object. The size of the first conductive object can vary within a relatively large range. Preferably, the first conductive object is a graphite rod, the diameter of the graphite rod can be 1-50 mm, and the length can be 5-100 cm, where the length refers to the axial length of the graphite rod. The type and shape of the second conductive object are not specifically limited and can be composed of any conductive material, for example, it can be iron, copper, graphite, etc., preferably iron and graphite, and the shape can be rod-shaped, plate-shaped, etc., preferably rod-shaped. When electrolyzing, a certain distance can be maintained between the first conductive object and the second conductive object, for example, it can be 10-50 cm.

[0035] According to the present invention, in step S3, the method of taking out the solid is not specifically limited as long as the solid and the liquid can be separated, for example, centrifugal separation or filtration can be used. Preferably, step S3 further includes: washing, drying, and calcining the taken-out solid. The solution used for washing is not specifically limited, for example, deionized water can be used for washing; drying can be carried out in a vacuum drying oven. Preferably, vacuum drying is carried out at a temperature of 100-200 °C and a pressure of 0-0.1 MPa for 2-24 hours; calcining can be carried out in a muffle furnace or a tube furnace, the temperature can be 350-800 °C, the pressure is 0-0.2 MPa, and calcining can be carried out in an air atmosphere or an inert atmosphere. The inert gas that can be contained in the inert atmosphere can be nitrogen, argon, helium, carbon dioxide, etc.

[0036] In a specific embodiment of the present invention, in step S1, the first conductive object and the second conductive object respectively connected to the positive and negative electrodes of a DC power supply are placed in an aqueous solution of an organic base, and electrolyzed at a voltage of 20-80 V for 2-8 days.

[0037] According to the present invention, in step S1, the concentration of the carbon dot solution can vary within a relatively wide range. In a specific embodiment of the present invention, in step S1, the concentration of the carbon dot solution is 1-1000 mg / L, preferably 10-500 mg / L; the concentration of the organic base in the aqueous solution of the organic base is 10-2500 mmol / L, preferably 50-1500 mmol / L.

[0038] In one embodiment, in step S2, the temperature of the stirring and mixing is 20-80 °C, and the time is 2-18 hours. The present invention does not specifically limit the mixing method. For example, mechanical stirring can be used, and the conditions of mechanical stirring can be selected according to the actual situation. The mixing time refers to the time for mixing the titanium silicalite, the iron source, and the carbon dot solution together to obtain a slurry and then mixing the slurry.

[0039] According to the present invention, in step S2, the weight ratio of the amounts of the titanium silicalite, the iron source, and the carbon dot solution can vary within a relatively wide range, for example, 100:(0.5-50):(50-5000), preferably 100:(5-25):(100-2000). According to the present invention, the titanium silicalite is well-known to those skilled in the art. In one embodiment, the silicon-titanium molar ratio of the titanium silicalite is 15-150, preferably 20-100, and the titanium silicalite is microporous titanium silicalite and / or mesoporous titanium silicalite. Among them, the microporous titanium silicalite can be one or more of MFI, BEA, MOR, and FAU; the mesoporous titanium silicalite can be SBA-15 and / or MCM-41.

[0040] In a preferred specific embodiment, step S2 may include: mixing the titanium silicalite with the iron source and then mixing with the carbon dot solution to obtain an implementation mixture. The modified zeolite material prepared by the above method has better catalytic performance. The present invention does not specifically limit the temperature and time for mixing the titanium silicalite, the iron source, and the carbon dot solution, as long as the titanium silicalite, the iron source, and the carbon dot solution can be mixed evenly.

[0041] According to the present invention, the hydrothermal reaction is well-known to those skilled in the art. In a specific embodiment of the present invention, in step S3, the conditions of the hydrothermal reaction include: the temperature is 100-200 °C, and the time is 3-360 hours; preferably, the temperature is 100-180 °C, and the time is 6-96 hours. The present invention does not specifically limit the pressure of the hydrothermal reaction, and it can be carried out under autogenous pressure or external pressure, preferably under autogenous pressure. The hydrothermal reaction can be carried out in a heat-resistant and pressure-resistant closed container. The specific type of the heat-resistant and pressure-resistant closed container is not limited and is commonly used by those skilled in the art. For example, it can be a high-pressure reaction kettle, etc.

[0042] According to the present invention, the iron source may be an inorganic iron source and / or an organic iron source containing iron, and may be selected from one or more of iron nitrate, iron chloride, iron sulfate, iron phosphate, and iron acetate, preferably iron nitrate.

[0043] According to the present invention, the organic base is selected from urea, quaternary ammonium base compounds, aliphatic amine compounds, or alkanolamine compounds, or a combination of two or three of them.

[0044] According to the present invention, the general formula of the quaternary ammonium base compound is (R 1 )4NOH, where R 1 may be at least one of a straight-chain alkyl group with 1-4 carbon atoms and a branched-chain alkyl group with 3-4 carbon atoms. For example, R 1 may be methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, or methallyl, preferably n-propyl, that is, the quaternary ammonium base compound is tetrapropylammonium hydroxide. Preferably, the quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, or a combination of two or three of them.

[0045] According to the present invention, the general formula of the aliphatic amine compound is R 2 (NH2) n , where R 2 may be an alkyl group with 1-6 carbon atoms or an alkylene group with 1-6 carbon atoms. For example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, n-hexyl, methylene, ethylene, n-propylene, n-butylene, or n-hexylene, and n is an integer of 1 or 2. Preferably, the aliphatic amine compound is ethylamine, n-butylamine, butanediamine, or hexanediamine, or a combination of two or three of them.

[0046] According to the present invention, the general formula of the alkanolamine compound is (HOR 3 ) m NH (3-m) , where R 3 may be at least one of an alkyl group with 1-4 carbon atoms and an alkylene group with 3-4 carbon atoms, and m is 1, 2, or 3. Preferably, the alkanolamine compound is selected from monoethanolamine, diethanolamine, or triethanolamine, or a combination of two or three of them.

[0047] The second aspect of the present invention provides a modified zeolite material prepared by using the method provided in the first aspect of the present invention.

[0048] According to the present invention, the average particle size of the zeolite material can vary within a relatively wide range. In a specific embodiment of the present invention, the average particle size of the modified zeolite material is 20 - 600 nm, preferably 50 - 500 nm, and more preferably 100 - 300 nm. In a specific embodiment of the present invention, the external specific surface area accounts for 20 - 80% of the total specific surface area, preferably 30 - 60%; the ratio of the mesoporous pore volume to the total pore volume is 30 - 85%, preferably 40 - 70%. The average particle size of the modified zeolite material can be obtained by randomly selecting ten particles from the SEM photograph after performing SEM analysis on the modified zeolite material and calculating the average value of their maximum particle sizes.

[0049] In a specific embodiment of the present invention, when the modified zeolite material is subjected to a nitrogen constant temperature adsorption - desorption test, the desorption amount of the modified zeolite material accounts for 70 - 95% of the total desorption amount when P / P0 is 0.8, preferably 80 - 90%. In the nitrogen constant temperature adsorption - desorption characterization test of the modified zeolite material of the present invention, there is a lower desorption pressure difference; while for the zeolite material obtained by traditional synthesis, the relative desorption pressure difference is higher, and its desorption capacity at P / P0 = 0.8 accounts for 5 - 60% of the total desorption capacity required, generally 10 - 50%. The modified zeolite material of the present invention is more easily adsorbed and desorbed, more conducive to the diffusion of reactant and product molecules, and has a higher selectivity for the target product.

[0050] In a specific embodiment of the present invention, based on the dry - basis weight of the modified zeolite material, the iron content calculated as iron oxide is 0.1 - 5% by weight, preferably 0.5 - 3% by weight; the titanium content calculated as titanium oxide is 0.5 - 6% by weight, preferably 1 - 3% by weight; the balance is silicon oxide.

[0051] The third aspect of the present invention provides an application of the zeolite material provided in the second aspect of the present invention in benzene oxidation. In a preferred specific embodiment, the present invention provides an application of the zeolite material in the preparation of hydroquinone by benzene oxidation.

[0052] The following further illustrates the present invention through examples, but the present invention is not limited thereby.

[0053] The nitrogen constant temperature adsorption - desorption test of the sample was measured using a Quantachrome AS - 6B type analyzer at liquid nitrogen temperature.

[0054] The pore structure properties such as the specific surface area and pore volume of the sample were tested by the nitrogen adsorption volumetric method, using the BET and BJH calculation methods (see Petrochemical Analysis Methods (RIPP Experimental Methods), RIPP151 - 90, published by Science Press in 1990).

[0055] The iron and titanium contents of the sample were measured by the XRF method.

[0056] The average particle size of the sample was measured by a Mastersizer 3000 laser particle size analyzer according to the specified method.

[0057] The preparation examples are used to illustrate the modified zeolite materials of the present invention and their preparation methods, and the preparation comparative examples are used to illustrate zeolite materials different from those of the present invention and their preparation methods.

[0058] Example 1

[0059] S1. Add tetrapropylammonium hydroxide and distilled water into a 1000 mL beaker to form a 500 mL aqueous solution of organic base as the electrolyte. Place an anode graphite rod (diameter 8 mm, length 30 cm) and a cathode graphite rod (diameter 8 mm, length 30 cm) therein, and keep the distance between the anode graphite rod and the cathode rod at 10 cm. Connect the anode graphite rod to the positive pole of a DC power supply and the cathode rod to the negative pole of the DC power supply, and apply a voltage of 65 V for electrolysis for 3 days to obtain a carbon dot solution; the concentration of the carbon dot solution is 160 mg / L, and the content of tetrapropylammonium hydroxide in the aqueous solution of the organic base is 150 mmol / L.

[0060] S2. First, mix 25 g of titanium silicalite and 2 g of iron nitrate evenly, and then add 60 mL of the carbon dot solution obtained in step S1 and mix evenly. Stir at 75 °C for 3 hours to obtain a mixture; among them, the weight ratio of the amounts of titanium silicalite, iron nitrate, and carbon dot solution is 100:8:240.

[0061] S3. Put the mixture into a stainless steel autoclave, keep it at a constant temperature of 170 °C for 3 days, filter to obtain the solid of the hydrothermal reaction, wash this solid with deionized water, dry it at 110 °C for 1 hour, and calcine it in an air atmosphere at 550 °C for 3 hours to obtain the modified zeolite material A1. The data of its average particle size, the ratio of the external specific surface area to the total, the ratio of the mesopore volume to the total pore volume, the contents of iron and titanium, and the desorption capacity at P / P0 = 0.8 accounting for the total amount to be desorbed are shown in Table 1.

[0062] Example 2

[0063] The modified zeolite material A2 was prepared by the same method as in Example 1, except that in step S2, first mix 25 g of titanium silicalite and 5 g of iron nitrate, and then add 60 mL of the carbon dot solution and mix evenly. Stir at 75 °C for 3 hours to obtain a mixture; among them, the weight ratio of the amounts of titanium silicalite, iron nitrate, and carbon dot solution is 100:20:240.

[0064] Example 3

[0065] The modified zeolite material A3 was prepared by the same method as in Example 1, except that in step S2, instead of mixing step by step, 25 g of titanium silicalite zeolite, 2 g of iron nitrate and 60 mL of carbon dot solution were directly mixed evenly, and stirred at 75 °C for 3 hours to obtain a mixture.

[0066] Example 4

[0067] The modified zeolite material A4 was prepared by the same method as in Example 1, except that in step S2, after 25 g of titanium silicalite zeolite and 2 g of iron acetate were mixed evenly, 60 mL of the carbon dot solution obtained in step S1 was added and mixed evenly, and stirred at 75 °C for 3 hours to obtain a mixture.

[0068] Example 5

[0069] The modified zeolite material A5 was prepared by the same method as in Example 1, except that in step S1, electrolysis was carried out at a voltage of 15 V for 4 days to obtain a carbon dot solution; the concentration of the carbon dot solution was 100 mg / L, and the content of tetrapropylammonium hydroxide in the aqueous solution of the organic base was 200 mmol / L.

[0070] Example 6

[0071] The modified zeolite material A6 was prepared by the same method as in Example 1, except that in step S3, the hydrothermal reaction temperature was 200 °C and the time was 96 hours.

[0072] Comparative Example 1

[0073] Titanium silicalite zeolite, iron nitrate and 60 mL of water were mixed and placed in a stainless steel autoclave, kept at a constant temperature of 170 °C for 3 days, filtered to obtain the solid of the hydrothermal reaction, this solid was washed with deionized water, dried at 110 °C for 1 hour, and calcined in air atmosphere at 550 °C for 3 hours to obtain the modified zeolite material DB1.

[0074] Comparative Example 2

[0075] The modified zeolite material DB2 was prepared by the same method as in Example 1, except that in step S2, iron nitrate was not added, titanium silicalite zeolite and carbon dot solution were mixed, and stirred at 75 °C for 3 hours to obtain a mixture; wherein, the weight ratio of the amounts of titanium silicalite zeolite and carbon dot solution used was 100:240.

[0076] Comparative Example 3

[0077] The modified zeolite material DB3 was prepared in the same manner as in Example 1, except that in step S1, no organic base was added to the electrolyte; in step S2, 2 g of ferric nitrate and 25 g of titanium silicalite were mixed, and then 60 mL of the carbon dot solution prepared in step S1 was added and mixed evenly. Finally, the same mass of tetrapropylammonium hydroxide as that contained in the carbon dot solution in step S2 of Example 1 was added to obtain a mixture.

[0078] Test example

[0079] 2.5 g of the zeolite materials synthesized in the above examples and comparative examples were sequentially placed into a slurry bed reactor as catalysts. According to the molar ratio of benzene: hydrogen peroxide: acetone (solvent) = 1:5:8, 25 g of benzene was added to the reactor. The reaction temperature was 80 °C, and the reaction was carried out at this temperature for 6 hours. The oxidation products were analyzed by gas chromatography (GC: Agilent, 7890A) and gas chromatography - mass spectrometry (GC - MS: Thermo Fisher Trace ISQ). The results are shown in Table 1.

[0080] The following formulas were used to calculate the raw material conversion rate and the target product selectivity:

[0081] Benzene conversion rate = (the amount of benzene added before the reaction - the amount of benzene remaining after the reaction) / the amount of benzene added before the reaction × 100%;

[0082] Hydroquinone selectivity = the amount of hydroquinone produced after the reaction / (the amount of benzene added before the reaction - the amount of benzene remaining after the reaction) × 100%;

[0083] Table 1

[0084]

[0085] As can be seen from the data in Table 1, the zeolite material prepared by the method of the present invention has good catalytic reaction performance. When it is used for the oxidation of benzene to prepare hydroquinone, it can improve the conversion rate of the raw material and the selectivity to the target product hydroquinone.

[0086] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0087] In addition, it should be noted that, in the case of no contradiction, the various specific technical features described in the above specific embodiments can be combined in any suitable manner. To avoid unnecessary repetition, the present invention will not separately describe various possible combination methods.

[0088] In addition, any combination can be made among various different embodiments of the present invention, as long as it does not violate the idea of the present invention, and it should equally be regarded as the content disclosed by the present invention.

Claims

1. A method for preparing a modified zeolite material, the method comprising: S1. Placing a first conductive object and a second conductive object respectively connected to the positive electrode and the negative electrode of a DC power supply in an aqueous solution of an organic base, and electrolyzing for 1 - 10 days at a voltage of 10 - 100 V to obtain a carbon dot solution; wherein, the first conductive object is a graphite formed body; the concentration of the carbon dot solution is 10 - 500 mg / L; the concentration of the organic base in the aqueous solution of the organic base is 50 - 1500 mmol / L; The organic base is selected from urea, quaternary ammonium base compounds, aliphatic amine compounds or alkanolamine compounds, or a combination of two or three of them; the general formula of the quaternary ammonium base compounds is (R 1 )4NOH, where R 1 is at least one of a straight-chain alkyl group with 1-4 carbon atoms and a branched-chain alkyl group with 3-4 carbon atoms; the general formula of the aliphatic amine compounds is R 2 (NH2) n , where R 2 is an alkyl group with 1-6 carbon atoms or an alkylene group with 1-6 carbon atoms; the general formula of the alkanolamine compounds is (HOR 3 ) m NH (3-m) , where R 3 is at least one of an alkyl group with 1-4 carbon atoms and an alkylene group with 3-4 carbon atoms, and m is 1, 2 or 3; S2. Mixing titanium silicalite and iron nitrate uniformly and then stirring and mixing with the carbon dot solution at 20 - 90 °C for 1 - 12 h to obtain a mixture; the weight ratio of the amounts of the titanium silicalite, the iron nitrate, and the carbon dot solution is 100:(5 - 25):(100 - 2000); the silicon - titanium molar ratio of the titanium silicalite is 15 - 150, and the titanium silicalite is microporous titanium silicalite and / or mesoporous titanium silicalite; S3. After subjecting the mixture to a hydrothermal reaction, taking out the solid, washing, drying, and calcining to obtain the modified zeolite material.

2. The method according to claim 1, wherein, In step S1, the first conductive object and the second conductive object respectively connected to the positive electrode and the negative electrode of the DC power supply are placed in an aqueous solution of the organic base, and electrolyzed at a voltage of 20 - 80 V for 2 - 8 days.

3. The method according to claim 1, wherein, In step S3, the conditions of the hydrothermal reaction include: temperature is 100 - 200 °C, and time is 3 - 360 hours.

4. The method according to claim 3, wherein, In step S3, the conditions of the hydrothermal reaction include: temperature is 100 - 180 °C, and time is 6 - 96 hours.

5. The method according to claim 1, wherein The microporous titanium silicalite is one or more of MFI, BEA, MOR, and FAU; the mesoporous titanium silicalite is SBA - 15 and / or MCM - 41; The quaternary ammonium base compound is tetraethylammonium hydroxide, tetrapropylammonium hydroxide, or tetrabutylammonium hydroxide, or a combination of two or three of them; The fatty amine compound is ethylamine, n - butylamine, butanediamine, or hexanediamine, or a combination of two or three of them; The alkanolamine compound is selected from monoethanolamine, diethanolamine, or triethanolamine, or a combination of two or three of them.

6. The modified zeolite material prepared by the method according to any one of claims 1 - 5.

7. The modified zeolite material according to claim 6, wherein The average particle size of the modified zeolite material is 20 - 600 nm.

8. The modified zeolite material according to claim 7, wherein The average particle size of the modified zeolite material is 50 - 500 nm.

9. The modified zeolite material according to claim 7, wherein The average particle size of the modified zeolite material is 100 - 300 nm.

10. The modified zeolite material according to claim 7, wherein, The external specific surface area of the modified zeolite material accounts for 20 - 80% of the total specific surface area.

11. The modified zeolite material according to claim 7, wherein, The external specific surface area of the modified zeolite material accounts for 30 - 60% of the total specific surface area.

12. The modified zeolite material according to claim 7, wherein, The ratio of the mesoporous pore volume of the modified zeolite material to the total pore volume is 30 - 85%.

13. The modified zeolite material according to claim 7, wherein The ratio of the mesoporous pore volume of the modified zeolite material to the total pore volume is 40 - 70%.

14. The modified zeolite material according to claim 6, wherein, When the modified zeolite material is subjected to a nitrogen constant - temperature adsorption - desorption test, when P / P0 is 0.8, the desorption amount of the modified zeolite material accounts for 70 - 95% of the total desorption amount to be desorbed.

15. The modified zeolite material according to claim 14, wherein, When P / P0 is 0.8, the desorption amount of the modified zeolite material accounts for 80 - 90% of the total desorption amount to be desorbed.

16. The modified zeolite material according to claim 6, wherein Based on the dry basis weight of the modified zeolite material, the iron content in terms of iron oxide is 0.1-5% by weight; the titanium content in terms of titanium oxide is 0.5-6% by weight.

17. The modified zeolite material according to claim 16, wherein, Based on the dry basis weight of the modified zeolite material, the iron content in terms of iron oxide is 0.5-3% by weight, and the titanium content in terms of titanium oxide is 1-3% by weight.

18. Use of the modified zeolite material according to any one of claims 6-17 in the preparation of benzenediol by oxidation of benzene.

Images