CN116273100A - Preparation method of aromatic hydrocarbon ammoxidation catalyst - Google Patents

Abstract

The invention provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, belongs to the technical field of catalyst preparation, and can solve the technical problems of poor selectivity, poor stability and unsatisfactory catalyst activity of the existing ammoxidation catalyst. The technical scheme mainly comprises the following steps: magnesium-substituted mesoporous aluminum phosphate prepared by a gel sol method is taken as a carrier, and then mixed with an effective active component, an auxiliary component and an abrasion-resistant auxiliary, and then subjected to granulation and roasting treatment in sequence to prepare the aromatic hydrocarbon ammoxidation catalyst. The ammonia oxidation catalyst prepared by the invention has better wear resistance and stability while ensuring better catalytic activity and selectivity, effectively reduces the addition and replacement of the catalyst in the production process, reduces the production cost and ensures the stable operation of the ammonia oxidation reaction of aromatic hydrocarbon. The invention can be applied to the preparation of aromatic nitrile.

Description

Preparation method of aromatic hydrocarbon ammoxidation catalyst

Technical Field

The invention belongs to the technical field of catalyst preparation, and particularly relates to a preparation method of an aromatic hydrocarbon ammoxidation catalyst.

Background

Aromatic nitrile is an important organic intermediate, can synthesize a series of fine chemicals, and is widely applied to industries such as dyes, fragrances, special materials, pesticides, medicines and the like. For example, the chlorination reaction of terephthalonitrile and terephthalonitrile can prepare tetrachloro terephthalonitrile, which can be used for synthesizing herbicides chlorophthalic acid, pyrethrin insecticide and cerebral thrombosis medicine, and the hydrogenated product p-xylylenediamine is an important raw material of polyamide and is also a good epoxy resin curing agent.

At present, the preparation method of the aromatic nitrile mainly comprises a chemical synthesis method and a gas-phase ammoxidation method; wherein, the chemical synthesis method for preparing the aromatic nitrile has the defects of complex process, high cost, low yield, serious pollution and the like, and is eliminated. In industry, the one-step synthesis of aromatic nitrile by gas phase ammoxidation has short process and less pollution, and has become a mature technology for producing aromatic nitrile at present. There are still many technical problems to be solved in industrial production, wherein the research of efficient catalysts is the key of gas phase ammoxidation.

The ammoxidation of aromatic hydrocarbon is a complex reaction process, and has more side reactions besides the main reaction. The difficulty with the ammoxidation of aromatic hydrocarbons is that the performance of the ammoxidation catalyst is required to be not only high in activity but also good in selectivity. First, many oxidation catalysts are too active for aromatic ammoxidation reactions, which tend to cause excessive oxidation, and the decomposition rate of ammonia is also high, resulting in poor selectivity of the catalyst. Second, its smaller specific surface area, smaller number of active sites, results in lower catalytic activity. Therefore, in practical application, the active components are often supported 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 components, so that the degree of excessive oxidation is reduced, and the activity, selectivity and stability of the catalyst are improved. For example, the existing ammoxidation catalyst adopts silicon dioxide, alumina, molecular sieve and the like as carriers, but has small pore diameter and specific surface area, poor stability and low strength, so the catalyst activity is not ideal.

Therefore, how to select an ideal ammonia oxidation catalyst carrier, while ensuring that the catalyst has high catalytic activity, improving the stability of the catalyst and prolonging the service life of the catalyst is a key to solving the problems.

Disclosure of Invention

Aiming at the technical problems of poor selectivity, poor stability and unsatisfactory catalyst activity of the existing ammonia oxidation catalyst, the invention provides a preparation method of an aromatic hydrocarbon ammonia oxidation catalyst.

In order to achieve the above purpose, the invention adopts the following technical scheme:

the preparation method of the aromatic hydrocarbon ammoxidation catalyst comprises the steps of preparing magnesium-substituted mesoporous aluminum phosphate by a gel sol method, taking the magnesium-substituted mesoporous aluminum phosphate as a carrier, mixing with an effective active component, an auxiliary component and an abrasion-resistant auxiliary component, and sequentially granulating and roasting to obtain the aromatic hydrocarbon ammoxidation catalyst.

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

dissolving the weighed magnesium precursor, aluminum precursor and template agent in distilled water, and stirring at room temperature to obtain a mixed solution A;

the mixed solution A is vigorously stirred, meanwhile, an acidic solution is firstly added dropwise, then an alkaline solution is added dropwise, and continuous stirring is carried out until the pH value of the mixed solution A is 5.0, so that a mixed solution B is obtained;

and (3) sequentially carrying out vacuum drying and roasting treatment on the mixed solution B to obtain the magnesium-substituted mesoporous aluminum phosphate.

In an 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 agent 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 beta-cyclodextrin; the acid 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.

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

in one embodiment, the firing treatment temperature is 200-800 ℃, preferably 300-700 ℃, more preferably 550-650 ℃ when preparing the magnesium-substituted mesoporous aluminum phosphate.

In one embodiment, the stirring means comprises any one or more of double planetary stirring, high speed shearing, high speed emulsification, vacuum stirring or homogenizing shearing.

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;

the auxiliary component is selected from any one or more of molybdenum-containing element compounds, sodium-containing element compounds, potassium-containing element compounds, boron-containing element compounds, phosphorus-containing element compounds, copper-containing element compounds, nickel-containing element compounds, cobalt-containing element compounds, manganese-containing element compounds or iron-containing element compounds;

the wear-resistant auxiliary agent is selected from corundum, polyvinyl alcohol, graphite or ethylcellulose.

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

the copper-containing element compound, the nickel-containing element compound, the cobalt-containing element compound, the manganese-containing element compound and the iron-containing element compound are nitrate, chloride, sulfate or acetate containing copper element, nickel element, cobalt element, manganese element and iron element respectively.

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

the granulating 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 baking treatment temperature is 100 to 1000 ℃, preferably 300 to 800 ℃, more preferably 400 to 600 ℃.

In one embodiment, in a fluidized bed, the aromatic hydrocarbon ammoxidation catalyst according to any one of the above embodiments is used as a reaction catalyst, and air, ammonia gas and gasified aromatic hydrocarbon are mixed and enter the fluidized bed layer to perform subsequent ammoxidation reaction;

wherein the treatment temperature of the fluidized bed is 300-800 ℃, preferably 350-500 ℃, more preferably 380-430 ℃; the aromatic hydrocarbon is a compound having at least one aromatic ring selected from meta-xylene, para-xylene, ortho-xylene or 2, 6-dichlorotoluene.

Compared with the prior art, the invention has the advantages and positive effects that:

1. the invention provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, the catalyst takes magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, the carrier adopts small organic molecules as a template agent, magnesium, aluminum precursors and phosphoric acid (phosphorus source) as reaction raw materials, the catalyst is prepared by a gel sol method, the carrier is mixed with effective active components, auxiliary components and wear-resistant auxiliary (corundum powder, polyvinyl alcohol, graphite or ethylcellulose), and the catalyst is prepared by granulating and roasting, and the aromatic hydrocarbon ammoxidation catalyst prepared by the method has the characteristics of good catalytic activity, high catalytic selectivity and good stability;

2. the invention provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which adopts magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, wherein Metal Aluminum Phosphate (MAPOs) has the characteristics of flexible structural property, surface acidity and thermal stability, and aluminum phosphate oxide doped with Mg neutralizes the acidity of AlPO, has larger aperture, higher specific surface area and good stability, and is suitable for being used as an ammoxidation catalyst carrier;

3. the ammonia oxidation catalyst prepared by the preparation method provided by the invention has better wear resistance and stability while ensuring better catalytic activity and selectivity, so that the supplement and replacement of the catalyst in the production process are effectively reduced, the production cost is reduced, and the stable operation of the ammonia oxidation reaction of the aromatic hydrocarbon is ensured.

Detailed Description

The following description of the technical solutions in the embodiments of the present invention will be clear and complete, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

The embodiment of the invention provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which comprises the steps of preparing magnesium-substituted mesoporous aluminum phosphate by a gel sol method, taking the magnesium-substituted mesoporous aluminum phosphate as a carrier, mixing with an effective active component, an auxiliary component and an abrasion-resistant auxiliary component, and then sequentially granulating and roasting to obtain the aromatic hydrocarbon ammoxidation catalyst.

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which adopts magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, wherein Metal Aluminum Phosphate (MAPOs) has the characteristics of flexible structural property, surface acidity and thermal stability, aluminum phosphate oxide doped with Mg neutralizes the acidity of AlPO, has larger pore diameter and higher specific surface area, has good stability, is suitable for being used as an ammoxidation catalyst carrier, and has better wear resistance and stability while ensuring better catalytic activity and selectivity, thereby effectively reducing the supplement and replacement of the catalyst in the production process, reducing the production cost and ensuring the stable operation of an aromatic hydrocarbon ammoxidation reaction.

However, many conventional oxidation catalysts are too active for the ammoxidation of aromatic hydrocarbons, which tends to cause excessive oxidation, and the decomposition rate of ammonia is high, resulting in poor selectivity of the catalyst. Second, its smaller specific surface area, smaller number of active sites, results in lower catalytic activity. Therefore, in practical application, the active components are 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 components, so that the degree of excessive oxidation is reduced, and the activity, selectivity and stability of the catalyst are improved. For example, conventional ammoxidation catalysts use silica, alumina, molecular sieves and the like as carriers, but have small pore diameters and specific surface areas, poor stability and low strength, and thus the catalyst activity is not ideal. Therefore, the conventional ammonia oxidation catalyst still has a plurality of defects, and there is a need to develop a novel 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, etc. characteristics of the ammoxidation catalyst.

Further, in order to overcome the problems of the traditional ammoxidation catalyst, the invention firstly selects mesoporous aluminum phosphate (MgAPO) substituted by magnesium as a carrier, the carrier adopts small organic molecules as a template agent, magnesium and aluminum precursors and phosphoric acid (phosphorus source) as reaction raw materials, the carrier is prepared by a gel sol method, and the carrier is mixed with effective active components, auxiliary components and wear-resistant auxiliary (such as corundum powder, polyvinyl alcohol, graphite or ethylcellulose), and is prepared by granulating and roasting.

Furthermore, the invention takes magnesium-substituted mesoporous aluminum phosphate (MgAPO) as a carrier, wherein the structure of the aluminum phosphate material (APO) is formed by AlO ₄ Tetrahedra and PO ₄ The open framework with electric neutrality is formed by strictly and alternately connecting tetrahedrons, has flexible structural characteristics, and has surface acidity and stronger thermal stability. After the introduction of 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 may be partially replaced by other metal atoms to form additional acid-base centers or redox centers. Metal-substituted APO is therefore a preferred choice as an ammoxidation catalyst support. However, the differences in APO carrier preparation conditions lead to differences in the physicochemical properties of the catalyst, thereby affecting the activity and stability of the catalyst. In addition, the invention also defines that the content of the magnesium-substituted mesoporous aluminum phosphate in the aromatic hydrocarbon ammoxidation catalyst is 30 to 70 weight percent, preferably 40 to 60 weight percent, and particularly 30 weight percent, 40 weight percent, 50 weight percent, 60 weight percent and 70 weight percent or any value within the defined range falls within the protection scope of the invention.

It should be further noted that the invention only adopts magnesium-substituted mesoporous aluminum phosphate (MgAPO) as the carrier, and the expected effect still cannot be achieved, and also needs to consider a plurality of details. In its broadest aspect, the present invention further defines the effective active and auxiliary components used in the preparation of the ammoxidation catalyst.

Wherein the effective active component is selected from any one or more of vanadium-containing element compound, antimony-containing element compound, chromium-containing element compound, phosphorus-containing element compound, palladium-containing element compound, rhodium-containing element compound, titanium-containing element compound or cerium-containing element compound; the auxiliary component is selected from any one or more of molybdenum-containing element compound, sodium-containing element compound, potassium-containing element compound, boron-containing element compound, phosphorus-containing element compound, copper-containing element compound, nickel-containing element compound, cobalt-containing element compound, manganese-containing element compound or iron-containing element compound; the wear-resistant auxiliary agent is selected from corundum, polyvinyl alcohol, graphite or ethylcellulose. According to the invention, vanadium and antimony are used as effective active ingredients of the catalyst, copper, nickel, cobalt and manganese can also improve activity and increase single yield, molybdenum can assist desorption, the catalyst is protected, boron can disperse active sites of the catalyst, sodium and phosphorus are used for enhancing the wear resistance of the catalyst, and potassium is used for regulating the pH value of the catalyst.

Further, the vanadium-containing compound is selected from vanadium pentoxide, sodium 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 element-containing compound is selected from sodium nitrate, sodium acetate, sodium chloride, sodium carbonate, sodium sulfate or sodium oxalate; the compound containing potassium element is selected from potassium nitrate, potassium acetate, potassium chloride, potassium carbonate, potassium sulfate or potassium oxalate; the boron-containing element compound is selected from boric acid, methyl borate or boron trichloride; the phosphorus-containing element compound is selected from phosphoric acid, phosphomolybdic acid, sodium phosphate or sodium hydrogen phosphate; the copper-containing element compound, the nickel-containing element compound, the cobalt-containing element compound, the manganese-containing element compound and the iron-containing element compound are nitrate, chloride, sulfate or acetate containing copper element, nickel element, cobalt element, manganese element and iron element respectively.

Further, when the aromatic hydrocarbon ammoxidation catalyst is prepared, 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 baking treatment temperature is 100 to 1000 ℃, preferably 300 to 800 ℃, more preferably 400 to 600 ℃.

In conclusion, the particle size distribution range of the aromatic hydrocarbon ammoxidation catalyst prepared based on the preparation process is 30-90 microns, and the specific surface area of the aromatic hydrocarbon ammoxidation catalyst is 100-150 m ² /g, wherein the pore size distribution is 3.0-4.0 nm; wherein the particle size distribution range can be selected from 30 micrometers, 40 micrometers, 50 micrometers, 60 micrometers, 70 micrometers, 80 micrometers, 90 micrometers or the limit thereofAny numerical value within the fixed range falls within the protection scope of the invention; specific surface area can be selected to be 100m ² /g、110m ² /g、120m ² /g、130m ² /g、140m ² /g、150m ² Each micron or any number within the above-defined range falls within the scope of the present invention; the pore size distribution may 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 value within the above-defined ranges, which falls within the scope of the present invention.

In a specific embodiment, in a fluidized bed, the aromatic hydrocarbon ammoxidation catalyst according to any one of the above embodiments is used as a reaction catalyst, and air, ammonia gas and gasified aromatic hydrocarbon are mixed and enter the fluidized bed layer to perform subsequent ammoxidation reaction;

wherein the treatment temperature of the fluidized bed is 300-800 ℃, preferably 350-500 ℃, more preferably 380-430 ℃; the aromatic hydrocarbon is a compound having at least one aromatic ring selected from meta-xylene, para-xylene, ortho-xylene or 2, 6-dichlorotoluene.

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

s1, dissolving a weighed magnesium precursor, an weighed aluminum precursor and a weighed template agent in distilled water, and stirring at room temperature to obtain a mixed solution A;

in the 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 and 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 agent 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 beta-cyclodextrin.

Furthermore, in order to ensure that the performance of the magnesium-substituted mesoporous aluminum phosphate reaches the expected performance, the invention also defines the proportioning relation of different raw materials in the step S1, namely the molar ratio of the magnesium precursor to the aluminum precursor is (0.02-1): 1, preferably (0.05 to 0.5): 1, more preferably (0.1 to 0.3): 1. meanwhile, the stirring mode is selected from any one or more of double planetary stirring, high-speed shearing, high-speed emulsification, vacuum stirring or homogenizing shearing.

S2, vigorously stirring the mixed solution A, firstly dropwise adding an acidic solution into the mixed solution A, then dropwise adding an alkaline solution into the mixed solution A, and continuously stirring until the pH value of the mixed solution A is 5.0 to obtain a mixed solution B;

in the 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.

And S3, sequentially carrying out vacuum drying and roasting treatment on the mixed solution B to obtain the magnesium-substituted mesoporous aluminum phosphate.

In the step S3, the baking treatment temperature is 200 to 800 ℃, preferably 300 to 700 ℃, more preferably 550 to 650 ℃.

In order to more clearly and in detail describe the preparation method of the aromatic hydrocarbon ammoxidation catalyst provided by the embodiment of the present invention, the following description will be made with reference to specific examples.

Example 1

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

(1) Preparation of MgAPO carrier:

MgAPOs with different Mg/Al molar ratios are prepared by adopting a gel sol method: 16.4g of Mg (NO ₃ ) ₂ ·6H ₂ O,240g of Al (NO) ₃ ) ₃ ·9H ₂ O and 147.9g of Citric Acid (CA) were dissolved in 1L of distilled water and stirred at room temperature for 30min; 45.2mL of phosphoric acid (85 wt%) were then added dropwise with vigorous stirring; mg (NO) ₃ ) ₂ ·6H ₂ O/Al(NO ₃ ) ₃ ·9H ₂ O/CA/H ₃ PO ₄ /H ₂ O=0.1: 1.0:1.1:1.2:80; then, an aqueous ammonia solution (10 wt%) was added dropwise and continuously stirred to a pH of 5.0; aging at 25deg.C for 5 hr, vacuum dryingDrying in a box at 60 ℃ for 12 hours; and (3) placing the dried solid in a muffle furnace, and roasting for 3 hours in an air atmosphere at 600 ℃ to prepare the MgAPO carrier.

(2) Preparation of aromatic hydrocarbon ammoxidation catalyst:

288.8g of oxalic acid hydrate is weighed and dissolved in 250ml of distilled water, and 45.7g of vanadium pentoxide, 102.8g of ammonium antimonate 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 are respectively added under the condition of magnetic stirring at 80 ℃; dispersing 132.5g of MgAPO powder in 250ml of deionized water by ultrasonic to form uniform suspension; slowly adding the solution into the slurry after forming a uniform phase solution, stirring and curing for 2 hours at 80 ℃, evaporating and concentrating to 60% of the original weight, weighing 5wt% of corundum solid powder, adding the corundum solid powder into the obtained slurry, uniformly mixing and aging for 5 hours, carrying out spray granulation by a spray dryer, and drying for 12 hours at 120 ℃ in an oven. Placing the catalyst into a muffle furnace, pre-roasting the catalyst at 300 ℃ for 2 hours, and calcining the catalyst at 580 ℃ for 10 hours to obtain the aromatic hydrocarbon ammoxidation catalyst.

The obtained aromatic hydrocarbon ammoxidation catalyst is used in an aromatic hydrocarbon ammoxidation reaction. Wherein, the number of the ammoxidation reactors is 1

The loading of the aromatic hydrocarbon ammoxidation catalyst is 30ml; mixing ammonia gas, air and gasified aromatic hydrocarbon (n (NH 3: air: MX) =1:15:40), feeding into a fluidized bed reactor from the bottom at a certain feeding speed, reacting at a reaction pressure of 0.01-0.4MPa, a reaction temperature of 370-460 ℃ and a liquid flow rate of 50 mu l/min, and performing reaction evaluation for 50h, wherein the result is shown in table 1.

Example 2

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: mg (NO) in MgAPO carrier preparation step ₃ ) ₂ Is used in different amounts, i.e. Mg (NO ₃ ) ₂ ·6H ₂ O/Al(NO ₃ ) ₃ ·9H ₂ O/CA/H ₃ PO ₄ /H ₂ O=0.2: 1.0:1.1:1.2:80. the finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 3

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: mg (NO) in MgAPO carrier preparation step ₃ ) ₂ Different amounts of Mg (NO) ₃ ) ₂ ·6H ₂ O/Al(NO ₃ ) ₃ ·9H ₂ O/CA/H ₃ PO ₄ /H ₂ O=0.3: 1.0:1.1:1.2:80. the finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 4

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: mg (NO) in MgAPO carrier preparation step ₃ ) ₂ Different amounts of Mg (NO) ₃ ) ₂ ·6H ₂ O/Al(NO ₃ ) ₃ ·9H ₂ O/CA/H ₃ PO ₄ /H ₂ O=0: 1.0:1.1:1.2:80. the finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 5

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: the calcination temperature in the MgAPO carrier preparation step was 550 ℃. The finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 6

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: the calcination temperature in the MgAPO carrier preparation step was 650 ℃. The finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 7

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: corundum is replaced by polyvinyl alcohol in the preparation step of the aromatic hydrocarbon ammoxidation catalyst. The finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 8

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: corundum is replaced by graphite in the preparation step of the aromatic hydrocarbon ammoxidation catalyst. The finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Example 9

The embodiment provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which specifically comprises the following steps:

the preparation method of this example is the same as that of example 1, except that: corundum is replaced by ethyl cellulose in the preparation step of the aromatic hydrocarbon ammoxidation catalyst. The finally produced aromatic hydrocarbon ammoxidation catalyst was evaluated under the evaluation conditions as described in example 1, and the results are shown in Table 1.

Comparative example 1

The comparative example provides a preparation method of an aromatic hydrocarbon ammoxidation catalyst, which comprises the following specific steps:

the preparation method of this comparative example is the same as in example 1, except that: the MgAPO carrier was replaced with a commercial silica sol (catalyst specific, 30 wt%) with the remainder of example 1. The finally prepared aromatic hydrocarbon ammoxidation catalyst was evaluated under the above-mentioned evaluation conditions, and the results are shown in Table 1.

Evaluation results:

TABLE 1 evaluation results of ammoxidation of aromatic hydrocarbons by different catalysts

Based on the data in the table, examples 1 to 9 are aromatic hydrocarbon ammoxidation catalysts prepared by the preparation method of the aromatic hydrocarbon ammoxidation catalyst provided by the invention, and the aromatic hydrocarbon ammoxidation reaction of the catalysts is found that the aromatic hydrocarbon ammoxidation catalyst has high catalytic activity and low abrasion loss, can effectively reduce the catalyst consumption in the production process, and keeps the stable production of aromatic hydrocarbon ammoxidation.

Evaluation of stability of aromatic hydrocarbon ammoxidation catalyst:

the test adopts the aromatic hydrocarbon ammoxidation catalyst prepared in the embodiment 1, ammonia gas, air and gasified meta-xylene are mixed (n (NH 3: air: MX) =1:15:40), and are sent into a fluidized bed reactor from the bottom at a certain feeding speed, the reaction pressure is 0.01-0.4MPa, the reaction temperature is 380 ℃, the liquid flow rate is 50 mu l/min, the reaction evaluation is 500h, and the test result is shown in Table 2.

TABLE 2 catalyst stability test data

According to the stability evaluation test, the yields and the wear indexes of different time periods (50 h, 100h, 200h, 300h, 400h and 500 h) are tracked, so that in a normal catalytic reaction, the aromatic hydrocarbon ammoxidation catalyst prepared by the invention has good high-temperature sintering resistance and strong mechanical strength and wear resistance.

Claims (10)

1. The preparation method of the aromatic hydrocarbon ammoxidation catalyst is characterized in that magnesium-substituted mesoporous aluminum phosphate prepared by a gel sol method is used as a carrier, and the magnesium-substituted mesoporous aluminum phosphate is mixed with an effective active component, an auxiliary component and an abrasion-resistant auxiliary component and then subjected to granulation and roasting treatment in sequence to prepare the aromatic hydrocarbon ammoxidation catalyst.

2. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, wherein the magnesium-substituted mesoporous aluminum phosphate is prepared by the following method:

dissolving the weighed magnesium precursor, aluminum precursor and template agent in distilled water, and stirring at room temperature to obtain a mixed solution A;

the mixed solution A is vigorously stirred, meanwhile, an acidic solution is firstly added dropwise, then an alkaline solution is added dropwise, and continuous stirring is carried out until the pH value of the mixed solution A is 5.0, so that a mixed solution B is obtained;

and (3) sequentially carrying out vacuum drying and roasting treatment on the mixed solution B to obtain the magnesium-substituted mesoporous aluminum phosphate.

3. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 2, wherein 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 and 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 agent 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 beta-cyclodextrin; the acid 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.

4. The method for producing an aromatic hydrocarbon ammoxidation catalyst according to claim 2, wherein the molar ratio between the magnesium precursor and the aluminum precursor is (0.02 to 1): 1, preferably (0.05 to 0.5): 1, more preferably (0.1 to 0.3): 1.

5. the method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 2, wherein the baking treatment temperature is 200-800 ℃, preferably 300-700 ℃, more preferably 550-650 ℃ when preparing the magnesium-substituted mesoporous aluminum phosphate.

6. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 2, wherein the stirring means comprises any one or more of double planetary stirring, high-speed shearing, high-speed emulsification, vacuum stirring or homogenizing shearing.

7. The method for producing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, wherein the effective active ingredient is selected from any one or more of a vanadium-containing element compound, an antimony-containing element compound, a chromium-containing element compound, a phosphorus-containing element compound, a palladium-containing element compound, a rhodium-containing element compound, a titanium-containing element compound, and a cerium-containing element compound;

the auxiliary component is selected from any one or more of molybdenum-containing element compounds, sodium-containing element compounds, potassium-containing element compounds, boron-containing element compounds, phosphorus-containing element compounds, copper-containing element compounds, nickel-containing element compounds, cobalt-containing element compounds, manganese-containing element compounds or iron-containing element compounds;

the wear-resistant auxiliary agent is selected from corundum, polyvinyl alcohol, graphite or ethylcellulose.

8. The method for producing an aromatic hydrocarbon ammoxidation catalyst according to claim 7, wherein the vanadium-containing element compound is selected from the group consisting of vanadium pentoxide, sodium vanadate, ammonium metavanadate, vanadium sulfate and vanadium oxalate; the antimony-containing element compound is selected from antimony chloride, antimony oxalate, antimony ammonium oxalate or antimony potassium tartrate; the molybdenum-containing element compound is selected from molybdenum trioxide, phosphomolybdic acid or ammonium molybdate; the sodium element-containing compound is selected from sodium nitrate, sodium acetate, sodium chloride, sodium carbonate, sodium sulfate or sodium oxalate; the compound containing potassium element is selected from potassium nitrate, potassium acetate, potassium chloride, potassium carbonate, potassium sulfate or potassium oxalate; the boron-containing element compound is selected from boric acid, methyl borate or boron trichloride; the phosphorus-containing element compound is selected from phosphoric acid, phosphomolybdic acid, sodium phosphate or sodium hydrogen phosphate;

the copper-containing element compound, the nickel-containing element compound, the cobalt-containing element compound, the manganese-containing element compound and the iron-containing element compound are nitrate, chloride, sulfate or acetate containing copper element, nickel element, cobalt element, manganese element and iron element respectively.

9. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, wherein the particle size distribution of the aromatic hydrocarbon ammoxidation catalyst is in the range of 30 to 90 μm, and the specific surface area of the aromatic hydrocarbon ammoxidation catalyst is in the range of 100 to 150m ² /g, wherein the pore size distribution is 3.0-4.0 nm; the content of the magnesium-substituted mesoporous aluminum phosphate in the aromatic hydrocarbon ammoxidation catalyst is 30-70wt%, preferably 40-60wt%;

the granulating 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 baking treatment temperature is 100 to 1000 ℃, preferably 300 to 800 ℃, more preferably 400 to 600 ℃.

10. The method for preparing an aromatic hydrocarbon ammoxidation catalyst according to claim 1, wherein the aromatic hydrocarbon ammoxidation catalyst according to any one of claims 1 to 9 is used as a reaction catalyst in a fluidized bed, and air, ammonia gas and gasified aromatic hydrocarbon are mixed into the fluidized bed layer to carry out subsequent ammoxidation reaction;

wherein the treatment temperature of the fluidized bed is 300-800 ℃, preferably 350-500 ℃, more preferably 380-430 ℃; the aromatic hydrocarbon is a compound having at least one aromatic ring selected from meta-xylene, para-xylene, ortho-xylene or 2, 6-dichlorotoluene.