A method for preparing an aromatic hydrocarbon ammoxidation catalyst

Abstract

The present invention proposes a method for preparing an aromatic hydrocarbon ammonia oxidation catalyst, which belongs to the technical field of catalyst preparation and can solve the technical problems of poor selectivity, poor stability and unsatisfactory catalyst activity of existing ammonia oxidation catalysts. The technical scheme mainly includes: first preparing magnesium-substituted mesoporous aluminum phosphate by a gel sol method, and then using the magnesium-substituted mesoporous aluminum phosphate as a carrier, mixing with effective active components, auxiliary components and wear-resistant auxiliary agents, and then sequentially granulating and calcining to prepare an aromatic hydrocarbon ammonia oxidation catalyst. The ammonia oxidation catalyst prepared by the present invention can ensure good catalytic activity and selectivity while also having good wear resistance and stability, effectively reducing the addition and replacement of catalysts in the production process, reducing production costs, and ensuring the smooth operation of aromatic hydrocarbon ammonia oxidation reactions. The present invention can be applied to the preparation of aromatic nitriles.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst preparation, and in particular relates to a method for preparing an aromatic hydrocarbon ammoxidation catalyst. Background Art

[0002] Aromatic nitriles are important organic intermediates that can be used to synthesize a series of fine chemicals. They are widely used in dyes, fragrances, special materials, pesticides, and pharmaceuticals. For example, the chlorination of terephthalonitrile can produce tetrachloroterephthalonitrile, which can be used to synthesize herbicides such as chlorphthalic acid, pyrethroid insecticides, and cerebral thrombosis drugs. Its hydrogenation product, p-phenylenediamine, is an important raw material for polyamides and a good epoxy resin curing agent.

[0003] At present, the preparation methods of aromatic nitrile mainly include chemical synthesis and gas phase ammoxidation. Among them, the preparation of aromatic nitrile by chemical synthesis has the disadvantages of complex process, high cost, low yield and serious pollution, and has now been eliminated. In industry, the one-step synthesis of aromatic nitrile by gas phase ammoxidation has a short process and less pollution, and has become a relatively mature technology for producing aromatic nitrile. However, there are still many technical problems to be solved in industrial production, among which the research on efficient catalysts is the key to gas phase ammoxidation reaction.

[0004] The ammoxidation of aromatic hydrocarbons is a complex reaction process. In addition to the main reaction, there are many side reactions. The difficulty of the ammoxidation of aromatic hydrocarbons lies in the performance of the catalyst for the ammoxidation reaction, which requires not only high activity but also good selectivity. First of all, many oxidative catalysts are too active for the ammoxidation of aromatic hydrocarbons, which easily causes over-oxidation, and the decomposition rate of ammonia is also high, resulting in poor selectivity of the catalyst. Secondly, its specific surface area is small and the number of active sites is also small, resulting in low catalytic activity. Therefore, in practical applications, the active component is often loaded on a carrier to improve the selectivity and catalytic activity of the catalyst. Although the carrier itself has no catalytic activity, the carrier can interact with the active component to reduce the degree of over-oxidation and improve the activity, selectivity and stability of the catalyst. For example, existing ammoxidation catalysts use silica, alumina, molecular sieves, etc. as carriers, but the pore size and specific surface area are small, the stability is poor, and the strength is low, so the catalyst activity is not ideal.

[0005] Therefore, how to select an ideal ammonia oxidation catalyst carrier to improve catalyst stability and extend catalyst service life while ensuring that the catalyst has high catalytic activity is the key to solving the above problems. Summary of the invention

[0006] The present invention aims to solve the technical problems of poor selectivity, poor stability and unsatisfactory catalytic activity of existing ammonia oxidation catalysts, and proposes a method for preparing an aromatic hydrocarbon ammonia oxidation catalyst. The method uses magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier to prepare the catalyst, which can improve the catalyst stability and extend the catalyst service life while ensuring that the catalyst has high catalytic activity, effectively reduce the catalyst consumption in the production process, and maintain stable aromatic hydrocarbon ammonia oxidation production.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] A method for preparing an aromatic hydrocarbon ammoxidation catalyst comprises the following steps: firstly preparing magnesium-substituted mesoporous aluminum phosphate by a gel sol method, then using the magnesium-substituted mesoporous aluminum phosphate as a carrier, mixing it with an effective active component, an auxiliary component and a wear-resistant auxiliary agent, and then sequentially subjecting the mixture to granulation and calcination treatment to prepare the aromatic hydrocarbon ammoxidation catalyst.

[0009] In one embodiment, the magnesium-substituted mesoporous aluminum phosphate is prepared by the following method:

[0010] Dissolve the weighed magnesium precursor, aluminum precursor and template in distilled water and stir at room temperature to obtain a mixed solution A;

[0011] While vigorously stirring the mixed solution A, firstly dropwise add the acidic solution thereto, then dropwise add the alkaline solution, and continue stirring until the pH of the mixed solution A is 5.0, to obtain a mixed solution B;

[0012] The mixed solution B is subjected to vacuum drying and calcination treatments in sequence to prepare the magnesium-substituted mesoporous aluminum phosphate.

[0013] In one embodiment, the magnesium precursor is selected from any one or more of magnesium nitrate, magnesium acetate, magnesium chloride, magnesium sulfate, magnesium chromate, magnesium iodide, magnesium fluoride, magnesium phosphate or magnesium oxalate; the aluminum precursor is selected from any one or more of aluminum nitrate, aluminum acetate, aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite; the template is an organic small molecule, and the organic small molecule is selected from any one or more of citric acid, tartaric acid, malic acid, lactic acid, carboxyacetic acid, 2-carboxyisobutyric acid, urea, ascorbic acid or β-cyclodextrin; the acidic solution is phosphoric acid; the alkaline solution is selected from any one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate.

[0014] In one embodiment, the molar ratio between the magnesium precursor and the aluminum precursor is (0.02-1):1, preferably (0.05-0.5):1, and more preferably (0.1-0.3):1.

[0015] In one embodiment, when preparing the magnesium-substituted mesoporous aluminum phosphate, the calcination temperature is 200-800°C, preferably 300-700°C, and more preferably 550-650°C.

[0016] In one embodiment, the stirring method includes any one or more of double planetary stirring, high-speed shearing, high-speed emulsification, vacuum stirring or homogenous shearing.

[0017] In one embodiment, the effective active component is selected from any one or more of a vanadium-containing compound, an antimony-containing compound, a chromium-containing compound, a phosphorus-containing compound, a palladium-containing compound, a rhodium-containing compound, a titanium-containing compound or a cerium-containing compound;

[0018] The auxiliary agent component is selected from any one or more of a molybdenum-containing compound, a sodium-containing compound, a potassium-containing compound, a boron-containing compound, a phosphorus-containing compound, a copper-containing compound, a nickel-containing compound, a cobalt-containing compound, a manganese-containing compound or an iron-containing compound;

[0019] The wear-resistant additive is selected from corundum, polyvinyl alcohol, graphite or ethyl cellulose.

[0020] In one embodiment, the vanadium-containing compound is selected from vanadium pentoxide, sodium vanadate, ammonium vanadate, ammonium metavanadate, vanadium sulfate or vanadium oxalate; the antimony-containing compound is selected from antimony chloride, antimony oxalate, ammonium antimony oxalate or potassium antimony tartrate; the molybdenum-containing compound is selected from molybdenum trioxide, phosphomolybdic acid or ammonium molybdate; the sodium-containing compound is selected from sodium nitrate, sodium acetate, sodium chloride, sodium carbonate, sodium sulfate or sodium oxalate; the potassium-containing compound is selected from potassium nitrate, potassium acetate, potassium chloride, potassium carbonate, potassium sulfate or potassium oxalate; the boron-containing compound is selected from boric acid, methyl borate or boron trichloride; the phosphorus-containing compound is selected from phosphoric acid, phosphomolybdic acid, sodium phosphate or sodium hydrogen phosphate;

[0021] The copper-containing compound, nickel-containing compound, cobalt-containing compound, manganese-containing compound and iron-containing compound are nitrates, chlorides, sulfates or acetates containing copper, nickel, cobalt, manganese and iron respectively.

[0022] In one embodiment, the particle size distribution range of the aromatic hydrocarbon ammoxidation catalyst is 30-90 microns, and the specific surface area of ​​the aromatic hydrocarbon ammoxidation catalyst is 100-150 m 2 / g, and the pore size distribution is 3.0-4.0nm; the content of magnesium-substituted mesoporous aluminum phosphate in the aromatic hydrocarbon ammoxidation catalyst is 30-70wt%, preferably 40-60wt%;

[0023] The granulation process is selected from any one or more of an impregnation method, a deposition precipitation method, a spray drying method or a gel sol method; the calcination treatment temperature is 100 to 1000°C, preferably 300 to 800°C, and more preferably 400 to 600°C.

[0024] In one embodiment, in a fluidized bed, the aromatic hydrocarbon ammoxidation catalyst as described in any of the above embodiments is used as a reaction catalyst, and air, ammonia and gasified aromatic hydrocarbons are mixed and introduced into the fluidized bed layer for subsequent ammoxidation reaction;

[0025] The treatment temperature of the fluidized bed is 300-800°C, preferably 350-500°C, and more preferably 380-430°C; the aromatic hydrocarbon is a compound having at least one aromatic ring, and the compound having at least one aromatic ring is selected from m-xylene, p-xylene, o-xylene or 2,6-dichlorotoluene.

[0026] Compared with the prior art, the advantages and positive effects of the present invention are:

[0027] 1. The present invention provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, wherein the catalyst uses magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, and the carrier uses an organic small molecule as a template, and uses magnesium, aluminum precursors and phosphoric acid (phosphorus source) as reaction raw materials, and is prepared by a gel sol method. The carrier is then mixed with an effective active component, an auxiliary component and a wear-resistant auxiliary (corundum powder, polyvinyl alcohol, graphite or ethyl cellulose), and is prepared by granulation and roasting. The aromatic hydrocarbon ammoxidation catalyst prepared by the method has the characteristics of good catalytic activity, high catalytic selectivity and good stability;

[0028] 2. The present invention provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, wherein the catalyst uses magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, wherein metal aluminum phosphates (MAPOs) have the characteristics of flexible structural properties, surface acidity and thermal stability, and the aluminum phosphate oxide doped with Mg element neutralizes the acidity of AlPO, and has a larger pore size, a higher specific surface area, and good stability, and is suitable for use as an ammoxidation catalyst carrier;

[0029] 3. The present invention provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst. The prepared ammoxidation catalyst can ensure good catalytic activity and selectivity while also having good wear resistance and stability, effectively reducing the addition and replacement of the catalyst in the production process, reducing production costs, and ensuring the smooth operation of the aromatic hydrocarbon ammoxidation reaction. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] The embodiment of the present invention provides a method for preparing an aromatic hydrocarbon ammonia oxidation catalyst, wherein magnesium-substituted mesoporous aluminum phosphate is first prepared by a gel sol method, and then the magnesium-substituted mesoporous aluminum phosphate is used as a carrier, mixed with an effective active component, an auxiliary component and a wear-resistant auxiliary agent, and then granulated and calcined in sequence to prepare the aromatic hydrocarbon ammonia oxidation catalyst.

[0032] The above embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, which uses magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, wherein metal aluminum phosphates (MAPOs) have flexible structural properties, surface acidity and thermal stability. The aluminum phosphate oxide doped with Mg element neutralizes the acidity of AlPO and has a larger pore size, a higher specific surface area and good stability, and is suitable for use as an ammoxidation catalyst carrier. The ammoxidation catalyst prepared by the preparation method provided by the embodiment of the present invention can ensure good catalytic activity and selectivity while also having good wear resistance and stability, effectively reducing the addition and replacement of the catalyst in the production process, reducing production costs, and ensuring the smooth operation of the aromatic hydrocarbon ammoxidation reaction.

[0033] However, many traditional oxidation catalysts are too active for aromatic ammoxidation reactions, which can easily cause over-oxidation, and the decomposition rate of ammonia is also high, resulting in poor selectivity of the catalyst. Secondly, its specific surface area is small and the number of active sites is also small, resulting in low catalytic activity. Therefore, in practical applications, the active component is often loaded on a carrier to improve the selectivity and catalytic activity of the catalyst. Although the carrier itself has no catalytic activity, the carrier can interact with the active component to reduce the degree of over-oxidation and improve the activity, selectivity and stability of the catalyst. For example, existing ammonia oxidation catalysts use silica, alumina, molecular sieves, etc. as carriers, but the pore size and specific surface area are small, the stability is poor, the strength is low, and the catalyst activity is not ideal. It can be seen that traditional ammonia oxidation catalysts still have many drawbacks, and it is urgent to develop a new type of ammonia oxidation catalyst with good stability, high strength, high catalytic activity and long service life. Among them, selecting a more suitable carrier is an effective way to improve the catalytic activity, strength, stability and other characteristics of ammonia oxidation catalysts.

[0034] Furthermore, in order to overcome the above-mentioned problems existing in traditional ammonia oxidation catalysts, the present invention selects magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier for the first time, and the carrier adopts organic small molecules as templates, magnesium, aluminum precursors and phosphoric acid (phosphorus source) as reaction raw materials, and is prepared by a gel sol method. The carrier is then mixed with effective active components, auxiliary components and wear-resistant additives (for example, corundum powder, polyvinyl alcohol, graphite or ethyl cellulose), and prepared by granulation and calcination.

[0035] Furthermore, the present invention uses "magnesium-substituted mesoporous aluminum phosphate (MgAPO)" as a carrier, wherein the structure of the aluminum phosphate material (APO) is an electrically neutral open framework formed by strictly alternating AlO4 tetrahedrons and PO4 tetrahedrons, with flexible structural characteristics, surface acidity and strong thermal stability. After introducing other metals (e.g., Fe, Ni, V, Ti, Cu, Zn, Mg, etc.) on the basis of this material, the Al or P atoms in the lattice can be partially replaced by other metal atoms to form additional acid-base centers or redox centers. Therefore, metal-substituted APO is a better choice as an ammonia oxidation catalyst carrier. However, different preparation conditions of the APO carrier lead to different physical and chemical properties of the catalyst, thereby affecting the activity and stability of the catalyst. In addition, the present invention also defines the content of magnesium-substituted mesoporous aluminum phosphate in the aromatic hydrocarbon ammonia oxidation catalyst as 30-70wt%, preferably 40-60wt%, and specifically 30wt%, 40wt%, 50wt%, 60wt%, 70wt% or any value within the above-defined range can be selected to fall within the protection scope of the present invention.

[0036] It should be noted that the present invention cannot achieve the expected effect by only using magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, and many details need to be taken into consideration at the same time. In detail, the present invention further defines the effective active components and auxiliary components used in the preparation of the ammonia oxidation catalyst.

[0037] Among them, the effective active component is selected from any one or more of vanadium-containing compounds, antimony-containing compounds, chromium-containing compounds, phosphorus-containing compounds, palladium-containing compounds, rhodium-containing compounds, titanium-containing compounds or cerium-containing compounds; the auxiliary agent component is selected from any one or more of molybdenum-containing compounds, sodium-containing compounds, potassium-containing compounds, boron-containing compounds, phosphorus-containing compounds, copper-containing compounds, nickel-containing compounds, cobalt-containing compounds, manganese-containing compounds or iron-containing compounds; the wear-resistant auxiliary agent is selected from corundum, polyvinyl alcohol, graphite or ethyl cellulose. The present invention uses vanadium and antimony as the effective active components of the catalyst, copper, nickel, cobalt and manganese can also improve the activity and increase the single yield, molybdenum can assist desorption and protect the catalyst, boron can disperse the active sites of the catalyst, sodium and phosphorus are used to enhance the wear resistance of the catalyst, and potassium is used to adjust the pH of the catalyst.

[0038] Further, the vanadium-containing compound is selected from vanadium pentoxide, sodium vanadate, ammonium vanadate, ammonium metavanadate, vanadium sulfate or vanadium oxalate; the antimony-containing compound is selected from antimony chloride, antimony oxalate, ammonium antimony oxalate or potassium antimony tartrate; the molybdenum-containing compound is selected from molybdenum trioxide, phosphomolybdic acid or ammonium molybdate; the sodium-containing compound is selected from sodium nitrate, sodium acetate, sodium chloride, sodium carbonate, sodium sulfate or sodium oxalate; the potassium-containing compound is selected from potassium nitrate, potassium acetate, potassium chloride, potassium carbonate, potassium sulfate or potassium oxalate; the boron-containing compound is selected from boric acid, methyl borate or boron trichloride; the phosphorus-containing compound is selected from phosphoric acid, phosphomolybdic acid, sodium phosphate or sodium hydrogen phosphate; the copper-containing compound, nickel-containing compound, cobalt-containing compound, manganese-containing compound and iron-containing compound are nitrates, chlorides, sulfates or acetates containing copper, nickel, cobalt, manganese and iron, respectively.

[0039] Furthermore, when preparing the aromatic ammoxidation catalyst of the present invention, the granulation process is selected from any one or more of the impregnation method, the deposition precipitation method, the spray drying method or the gel sol method; the calcination treatment temperature is 100 to 1000°C, preferably 300 to 800°C, and more preferably 400 to 600°C.

[0040] In summary, the particle size distribution range of the aromatic hydrocarbon ammoxidation catalyst prepared based on the above preparation process is 30-90 microns, and the specific surface area of ​​the aromatic hydrocarbon ammoxidation catalyst is 100-150m 2 / g, pore size distribution is 3.0-4.0nm; wherein the particle size distribution range can be specifically selected from 30 microns, 40 microns, 50 microns, 60 microns, 70 microns, 80 microns, 90 microns or any value within the above-defined range falls within the protection scope of the present invention; the specific surface area can be specifically selected from 100m 2 / g, 110m 2 / g, 120m 2 / g, 130m 2 / g, 140m 2 / g, 150m 2 / g micrometer or any numerical value within the above-defined range falls within the protection scope of the present invention; the pore size distribution can be specifically selected from 3.0nm, 3.1nm, 3.2nm, 3.3nm, 3.4nm, 3.5nm, 3.6nm, 3.7nm, 3.8nm, 3.9nm, 4.0nm or any numerical value within the above-defined range falls within the protection scope of the present invention.

[0041] In one specific embodiment, in a fluidized bed, the aromatic hydrocarbon ammoxidation catalyst as described in any of the above embodiments is used as a reaction catalyst, and air, ammonia and gasified aromatic hydrocarbons are mixed and introduced into the fluidized bed layer for subsequent ammoxidation reaction;

[0042] The treatment temperature of the fluidized bed is 300-800°C, preferably 350-500°C, and more preferably 380-430°C; the aromatic hydrocarbon is a compound having at least one aromatic ring, and the compound having at least one aromatic ring is selected from m-xylene, p-xylene, o-xylene or 2,6-dichlorotoluene.

[0043] In one specific embodiment, the magnesium-substituted mesoporous aluminum phosphate is prepared by the following method:

[0044] S1. Dissolve the weighed magnesium precursor, aluminum precursor and template in distilled water and stir at room temperature to obtain a mixed solution A;

[0045] In the above step S1, the magnesium precursor is selected from any one or more of magnesium nitrate, magnesium acetate, magnesium chloride, magnesium sulfate, magnesium chromate, magnesium iodide, magnesium fluoride, magnesium phosphate or magnesium oxalate; the aluminum precursor is selected from any one or more of aluminum nitrate, aluminum acetate, aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite; the template is an organic small molecule, and the organic small molecule is selected from any one or more of citric acid, tartaric acid, malic acid, lactic acid, carboxyacetic acid, 2-carboxyisobutyric acid, urea, ascorbic acid or β-cyclodextrin.

[0046] Furthermore, in order to ensure that the performance of the magnesium-substituted mesoporous aluminum phosphate reaches the expected level, the present invention further defines the ratio of different raw materials in step S1, that is, the molar ratio between the magnesium precursor and the aluminum precursor is (0.02-1): 1, preferably (0.05-0.5): 1, and more preferably (0.1-0.3): 1. At the same time, the stirring method is selected from any one or more of double planetary stirring, high-speed shearing, high-speed emulsification, vacuum stirring or homogenous shearing.

[0047] S2, vigorously stirring the mixed solution A, while first dropping an acidic solution therein, then dropping an alkaline solution therein, and continuously stirring until the pH of the mixed solution A is 5.0, to obtain a mixed solution B;

[0048] In the above step S2, the acidic solution is phosphoric acid; the alkaline solution is selected from any one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate.

[0049] S3. The mixed solution B is vacuum dried and calcined in sequence to prepare the magnesium-substituted mesoporous aluminum phosphate.

[0050] In the above step S3, the calcination treatment temperature is 200-800°C, preferably 300-700°C, and more preferably 550-650°C.

[0051] In order to more clearly and in detail introduce the preparation method of an aromatic hydrocarbon ammoxidation catalyst provided by an embodiment of the present invention, it will be described below in conjunction with specific embodiments.

[0052] Example 1

[0053] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0054] (1) Preparation of MgAPO carrier:

[0055] MgAPOs with different Mg / Al molar ratios were prepared by the gel sol method: 16.4 g of Mg(NO3)2·6H2O, 240 g of Al(NO3)3·9H2O and 147.9 g of citric acid (CA) were dissolved in 1 L of distilled water and stirred at room temperature for 30 min; then 45.2 mL of phosphoric acid (85 wt%) was added dropwise under vigorous stirring; Mg(NO3)2·6H2O / Al(NO3)3·9H2O / CA / H3PO4 / H2O=0.1:1.0:1.1:1.2:80; then, an ammonia solution (10 wt%) was added dropwise and stirred continuously until the pH was 5.0; after aging at 25°C for 5 h, the mixture was placed in a vacuum drying oven and dried at 60°C for 12 h; the dried solid was placed in a muffle furnace and calcined in an air atmosphere at 600°C for 3 h to prepare a MgAPO carrier.

[0056] (2) Preparation of Aromatic Hydrocarbon Ammoxidation Catalyst:

[0057] 288.8g of oxalic acid hydrate was weighed and dissolved in 250ml of distilled water. Under magnetic stirring at 80°C, 45.7g of vanadium pentoxide, 102.8g of ammonium antimony oxalate hydrate, 28.0g of ammonium molybdate, 26.2g of phosphomolybdic acid, 15.2g of potassium nitrate, 6.0g of sodium nitrate and 10.57g of boric acid were added respectively. 132.5g of MgAPO powder was ultrasonically dispersed in 250ml of deionized water to form a uniform suspension. After a homogeneous solution was formed, it was slowly added to the above slurry, stirred and aged at 80°C for 2h, and then evaporated and concentrated to 60% of the original weight. Then 5wt% of corundum solid powder was weighed and added to the obtained slurry. After mixing evenly and aging for 5h, it was spray granulated with a spray dryer and placed in an oven at 120°C for 12h. The product was placed in a muffle furnace, pre-baked at 300°C for 2 hours, and then calcined at 580°C for 10 hours to obtain an aromatic ammoxidation catalyst.

[0058] The obtained aromatic ammoxidation catalyst is used in the aromatic ammoxidation reaction. A quartz tubular reactor was used, and the loading amount of the aromatic ammoxidation catalyst was 30 ml; ammonia, air and vaporized aromatics were mixed (n(NH3:air:MX)=1:15:40) and fed into the fluidized bed reactor from the bottom at a certain feed rate. The reaction pressure was 0.01-0.4 MPa, the reaction temperature was 370-460°C, the liquid flow rate was 50 μl / min, and the reaction was evaluated for 50 hours. The results are shown in Table 1.

[0059] Example 2

[0060] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0061] The preparation method of this embodiment is the same as that of embodiment 1, except that the amount of Mg(NO3)2 used in the MgAPO carrier preparation step is different, that is, Mg(NO3)2·6H2O / Al(NO3)3·9H2O / CA / H3PO4 / H2O=0.2:1.0:1.1:1.2:80. The finally prepared aromatic ammoxidation catalyst was evaluated using the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0062] Example 3

[0063] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0064] The preparation method of this embodiment is the same as that of embodiment 1, except that the amount of Mg(NO3)2 used in the MgAPO carrier preparation step is different, namely, Mg(NO3)2·6H2O / Al(NO3)3·9H2O / CA / H3PO4 / H2O=0.3:1.0:1.1:1.2:80. The finally prepared aromatic ammoxidation catalyst was evaluated under the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0065] Example 4

[0066] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0067] The preparation method of this embodiment is the same as that of embodiment 1, except that the amount of Mg(NO3)2 used in the MgAPO carrier preparation step is different, namely, Mg(NO3)2·6H2O / Al(NO3)3·9H2O / CA / H3PO4 / H2O=0:1.0:1.1:1.2:80. The finally prepared aromatic ammoxidation catalyst was evaluated under the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0068] Example 5

[0069] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0070] The preparation method of this embodiment is the same as that of embodiment 1, except that the calcination temperature in the MgAPO carrier preparation step is 550° C. The aromatic ammoxidation catalyst finally prepared was evaluated using the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0071] Example 6

[0072] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0073] The preparation method of this embodiment is the same as that of embodiment 1, except that the calcination temperature in the MgAPO carrier preparation step is 650° C. The finally prepared aromatic ammoxidation catalyst was evaluated using the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0074] Example 7

[0075] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0076] The preparation method of this embodiment is the same as that of embodiment 1, except that corundum is replaced by polyvinyl alcohol in the preparation step of the aromatic hydrocarbon ammoxidation catalyst. The aromatic hydrocarbon ammoxidation catalyst finally prepared was evaluated using the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0077] Example 8

[0078] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0079] The preparation method of this embodiment is the same as that of embodiment 1, except that the corundum is replaced by graphite in the preparation step of the aromatic hydrocarbon ammoxidation catalyst. The aromatic hydrocarbon ammoxidation catalyst finally prepared was evaluated using the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0080] Example 9

[0081] This embodiment provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0082] The preparation method of this embodiment is the same as that of embodiment 1, except that corundum is replaced by ethyl cellulose in the preparation step of the aromatic hydrocarbon ammoxidation catalyst. The aromatic hydrocarbon ammoxidation catalyst finally prepared was evaluated using the evaluation conditions described in embodiment 1, and the results are shown in Table 1.

[0083] Comparative Example 1

[0084] This comparative example provides a method for preparing an aromatic hydrocarbon ammoxidation catalyst, specifically:

[0085] The preparation method of this comparative example is the same as that of Example 1, except that the MgAPO carrier is replaced by commercial silica sol (catalyst-specific, 30 wt%), and the rest is the same as Example 1. The finally prepared aromatic ammoxidation catalyst is evaluated under the above evaluation conditions, and the results are shown in Table 1.

[0086] Evaluation results:

[0087] Table 1 Evaluation results of aromatic ammoxidation reaction with different catalysts

[0088]

[0089]

[0090] Based on the data in the above table, it can be seen that Examples 1-9 are aromatic ammoxidation catalysts prepared by the preparation method of the aromatic ammoxidation catalyst provided by the present invention. When these catalysts are subjected to aromatic ammoxidation reaction, it is found that the aromatic ammoxidation catalyst has high catalytic activity and low wear, and can effectively reduce the catalyst consumption in the production process and maintain stable aromatic ammoxidation production.

[0091] Stability evaluation of aromatic ammoxidation catalysts:

[0092] In this test, the aromatic ammoxidation catalyst prepared in Example 1 was used. Ammonia, air and gasified meta-xylene were mixed (n(NH3:air:MX)=1:15:40) and fed into the fluidized bed reactor from the bottom at a certain feed rate. The reaction pressure was 0.01-0.4MPa, the reaction temperature was 380°C, the liquid flow rate was 50μl / min, the reaction was evaluated for 500h, and the test results are shown in Table 2.

[0093] Table 2 Catalyst stability experimental data

[0094]

[0095]

[0096] The above stability evaluation test, by tracking the yield and wear index at different time stages (50h, 100h, 200h, 300h, 400h, 500h), found that in a normal catalytic reaction, the aromatic ammoxidation catalyst prepared by the present invention has good resistance to high-temperature sintering, and has strong mechanical strength and wear resistance.

Claims

1. A method for preparing an aromatic hydrocarbon ammoxidation catalyst, characterized in that: The magnesium-substituted mesoporous aluminum phosphate is first prepared by a gel sol method, and then the magnesium-substituted mesoporous aluminum phosphate is used as a carrier, mixed with an effective active component, an auxiliary component and a wear-resistant auxiliary agent, and then granulated and calcined at 400-600° C. to prepare the aromatic ammoxidation catalyst. The aromatic ammoxidation catalyst has a particle size distribution range of 30-90 microns and a specific surface area of ​​100-150 m 2 / g, pore size distribution is 3.0~4.0nm; among them, The effective active components include vanadium-containing compounds and antimony-containing compounds, and the auxiliary agent components include molybdenum-containing compounds, phosphorus-containing compounds, potassium-containing compounds, sodium-containing compounds and boron-containing compounds; The content of magnesium-substituted mesoporous aluminum phosphate in the aromatic hydrocarbon ammoxidation catalyst is 30-70wt%, and the magnesium-substituted mesoporous aluminum phosphate is prepared by the following method: Dissolve the weighed magnesium precursor, aluminum precursor and template in distilled water and stir at room temperature to obtain a mixed solution A; While vigorously stirring the mixed solution A, firstly dropwise add a phosphoric acid solution thereto, then dropwise add an alkaline solution, and continue stirring until the pH of the mixed solution A is 5.0, to obtain a mixed solution B; The mixed solution B is subjected to vacuum drying and calcination in sequence to prepare the magnesium-substituted mesoporous aluminum phosphate; When preparing the magnesium-substituted mesoporous aluminum phosphate, the molar ratio between the magnesium precursor and the aluminum precursor is (0.1-0.3):1, and the calcination treatment temperature is 550-650°C.

2. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, characterized in that: The magnesium precursor is selected from any one or more of magnesium nitrate, magnesium acetate, magnesium chloride, magnesium sulfate, magnesium chromate, magnesium iodide, magnesium fluoride, magnesium phosphate or magnesium oxalate; the aluminum precursor is selected from any one or more of aluminum nitrate, aluminum acetate, aluminum chloride, aluminum sulfate, aluminum isopropoxide or pseudo-boehmite; the template is an organic small molecule, and the organic small molecule is selected from any one or more of citric acid, tartaric acid, malic acid, lactic acid, carboxyacetic acid, 2-carboxyisobutyric acid, urea, ascorbic acid or β-cyclodextrin; the alkaline solution is selected from any one or more of ammonia water, sodium hydroxide, potassium hydroxide, sodium carbonate or sodium bicarbonate.

3. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, characterized in that: The stirring method includes any one or more of double planetary stirring, high-speed shearing, high-speed emulsification, vacuum stirring or homogenizing shearing.

4. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, characterized in that: The wear-resistant additive is selected from corundum, polyvinyl alcohol, graphite or ethyl cellulose.

5. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, characterized in that: The vanadium-containing compound is selected from vanadium pentoxide, sodium vanadate, ammonium vanadate, ammonium metavanadate, vanadium sulfate or vanadium oxalate; the antimony-containing compound is selected from antimony chloride, antimony oxalate, ammonium antimony oxalate or potassium antimony tartrate; the molybdenum-containing compound is selected from molybdenum trioxide, phosphomolybdic acid or ammonium molybdate; the sodium-containing compound is selected from sodium nitrate, sodium acetate, sodium chloride, sodium carbonate, sodium sulfate or sodium oxalate; the potassium-containing compound is selected from potassium nitrate, potassium acetate, potassium chloride, potassium carbonate, potassium sulfate or potassium oxalate; the boron-containing compound is selected from boric acid, methyl borate or boron trichloride; the phosphorus-containing compound is selected from phosphoric acid, phosphomolybdic acid, sodium phosphate or sodium hydrogen phosphate.

6. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, characterized in that: The content of magnesium-substituted mesoporous aluminum phosphate in the aromatic hydrocarbon ammoxidation catalyst is 40-60wt%; The granulation process is selected from any one or more of a deposition precipitation method, a spray drying method or a gel sol method.

7. Use of the aromatic hydrocarbon ammoxidation catalyst obtained by the method for preparing the aromatic hydrocarbon ammoxidation catalyst according to any one of claims 1 to 6, characterized in that: In a fluidized bed, the aromatic hydrocarbon ammoxidation catalyst is used as a reaction catalyst, and air, ammonia and gasified aromatic hydrocarbons are mixed and introduced into the fluidized bed layer for subsequent ammoxidation reaction; The treatment temperature of the fluidized bed is 300-800° C.; the aromatic hydrocarbon is a compound having at least one aromatic ring, and the compound having at least one aromatic ring is selected from m-xylene, p-xylene, o-xylene or 2,6-dichlorotoluene.

8. The use of the aromatic hydrocarbon ammoxidation catalyst according to claim 7, characterized in that: The processing temperature of the fluidized bed is 350~500℃.

9. The use of the aromatic hydrocarbon ammoxidation catalyst according to claim 7, characterized in that: The processing temperature of the fluidized bed is 380~430℃.

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