An acrylonitrile catalyst based on MOF / SiO2 composite support and its preparation method

Abstract

This invention relates to the field of catalysts, and provides an acrylonitrile catalyst based on a MOF / SiO2 composite support and its preparation method. The acrylonitrile catalyst comprises, by weight, the following raw materials: 50-70 parts of active ingredient, 5-15 parts of rare earth precursor, 15-25 parts of MOF / SiO2 composite support, 20-40 parts of co-solvent, and 180-220 parts of deionized water. The acrylonitrile catalyst provided by this invention exhibits high activity, selectivity, and stability, and its application in acrylonitrile preparation results in high acrylonitrile yields.

Description

Technical Field

[0001] This invention relates to the field of catalysts, and in particular to an acrylonitrile catalyst based on a MOF / SiO2 composite support and its preparation method. Background Technology

[0002] Acrylonitrile, with the chemical formula C3H3N, is a core chemical raw material and a key polymer monomer. Its applications are wide-ranging and profound, primarily including, but not limited to, the production of synthetic fibers (such as acrylic fibers), as well as the manufacture of various polymer materials. Furthermore, acrylonitrile is a crucial raw material for the production of the surfactant polyacrylamide. In recent years, with the acceleration of global industrialization and the surge in demand for high-performance materials from emerging industries, the market demand for acrylonitrile has shown a year-on-year upward trend, further driving the continuous innovation and optimization of large-scale acrylonitrile production technology.

[0003] Currently, the mature and large-scale industrial production process for acrylonitrile uses propane or propylene as raw material, and carries out an ammonia oxidation reaction in a fixed fluidized bed reactor in the presence of ammonia, air, and a catalyst to produce acrylonitrile. Among these processes, the catalyst is one of the core technologies, and its research and improvement have always been emphasized. There are two main types: Mo-Bi based and Sb based catalysts, with Mo-Bi based catalysts dominating, accounting for 95% of the olefin oxidation market. Furthermore, the selectivity and activity of the catalyst are improved by introducing variable-valence metal components such as Fe, Ce, and rare earth elements.

[0004] However, in practical industrial applications, it has been found that after long-term operation, the selectivity and stability of acrylonitrile catalysts often decrease significantly due to various reasons such as low specific surface area, structural damage, and loss of active components. Therefore, researchers have also conducted extensive research on support technology. Materials with supporting functions, such as silica, have become commonly used support materials in acrylonitrile catalysts, which have improved the stability of the catalyst to a certain extent. However, silica alone as a support still needs to be improved in terms of specific surface area, porosity, and pore size uniformity. There is room for improvement in the uniformity and effect of active component adhesion on the support, as well as the activity and stability of the catalyst.

[0005] Patent CN 103691447A discloses a catalyst for producing acrylonitrile and its preparation method. The catalyst disclosed in this application consists of SiO2 as a support, a modifier, and an active component. The active component is bismuth nitrate and ammonium molybdate, and the modifier is at least one or more of ferric nitrate, manganese nitrate, nickel nitrate, magnesium nitrate, potassium nitrate, cesium nitrate, and chromium nitrate. The multi-component nature of the catalyst improves the yield of acrylonitrile. However, the support in this application is only SiO2, and its specific surface area, porosity, and pore size uniformity still need to be improved.

[0006] Therefore, there is an urgent need in the market for an acrylonitrile catalyst that incorporates a MOF / SiO2 composite support to enable the acrylonitrile catalyst to have high efficiency, selectivity and stability. Summary of the Invention

[0007] To address the problems existing in the prior art, this invention selects an active component composed of mixed salts, multi-metal compounds, and transition metal oxides as the main components, and combines it with rare earth precursors and co-solvents to design and incorporate a MOF / SiO2 composite support to prepare and synthesize an acrylonitrile catalyst based on the MOF / SiO2 composite support, which has the characteristics of high efficiency, selectivity, and stability.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0009] The present invention provides an acrylonitrile catalyst based on a MOF / SiO2 composite support. The acrylonitrile catalyst comprises the following raw materials by weight: 50-70 parts of active ingredient, 5-15 parts of rare earth precursor, 15-25 parts of MOF / SiO2 composite support, 20-40 parts of co-solvent, and 180-220 parts of deionized water.

[0010] In some embodiments of the present invention, the active ingredient comprises mixed salts, multi-metal compounds, and transition metal oxides.

[0011] In some embodiments of the present invention, the mixed salt is a mixture of ferric nitrate and nickel nitrate; the multi-metal compound is a mixture of bismuth molybdate and bismuth ferrite; and the transition metal oxide includes at least one of cobalt oxide, nickel oxide, and manganese oxide.

[0012] In some embodiments of the present invention, the rare earth precursor is cerium nitrate and / or lanthanum nitrate.

[0013] In some embodiments of the present invention, the preparation method of the MOF / SiO2 composite support includes the following steps:

[0014] (1) Add FeCl3·6H2O and 1,3,5-benzenetricarboxylic acid to DMF, heat the mixture with microwave, centrifuge, wash, and dry to obtain the product for later use;

[0015] (2) The product of step (1) and 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol were added to a mixed solution of DMF and anhydrous ethanol, ultrasonically dispersed, heated to reflux at 90-105℃ for 10-13h, cooled to room temperature, washed, and dried to obtain MOF material for later use;

[0016] (3) Mix the MOF material from step (2) with SiO2 and ball mill to obtain the MOF / SiO2 composite carrier.

[0017] In some embodiments of the present invention, in step (1), the molar ratio of FeCl3·6H2O and 1,3,5-benzenetricarboxylic acid is (2.5-3.5):1.

[0018] Preferably, in step (1), the molar ratio of FeCl3·6H2O to 1,3,5-benzenetricarboxylic acid is 3:1.

[0019] In some embodiments of the present invention, in step (2), the mass ratio of the product to 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol is 1:(0.3-0.5).

[0020] Preferably, in step (2), the mass ratio of the product to 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol is 1:0.4.

[0021] In some embodiments of the present invention, in step (2), the low-temperature resistant filler is a mixture of silica powder and nano-calcium carbonate.

[0022] In some embodiments of the present invention, in step (3), the mass ratio of SiO2 to MOF material is 1:(0.01-0.05).

[0023] Preferably, in step (3), the mass ratio of SiO2 to MOF material is 1:0.03.

[0024] To improve the dispersion performance and effectiveness of active components in acrylonitrile catalysts, active components and supports are often used in combination. Currently, the conventional support components on the market are composed of porous materials such as silica or montmorillonite. However, silica alone as a support has limited specific surface area and porosity, so its loading effect still needs to be improved.

[0025] To address the aforementioned issues, the applicant chose to synthesize a MOF material for use in conjunction with silica. MOF materials possess high porosity and ultra-large specific surface area; when combined with silica as a composite carrier, this allows for more uniform attachment of active ingredients and better loading performance. Firstly, the applicant synthesized iron-based MOF materials (products) using a microwave hydrothermal method, replacing the high-temperature, high-pressure reaction in traditional MOF material synthesis, making the process safer and more economical. Furthermore, by controlling microwave conditions such as time, temperature, and power, the applicant ensured that the synthesized iron-based MOF material exhibited greater porosity, more active sites, and good thermal stability, allowing for better loading of active ingredients. The iron-based components also function as active ingredients. Further, the applicant introduced 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol to react with the iron-based... MOF materials are modified by introducing pyridine and phenylethylene skeletons into the iron-based MOF material structure through coordination and hydrogen bonding, thereby improving the stability of the iron-based MOF material. Finally, the applicant mixes MOF materials and SiO2 in a specific ratio to obtain a MOF / SiO2 composite support, which has the advantages of multiple active sites, high specific surface area and high thermal stability, improving the loading effect of active components. In addition, the organic components in the MOF material disappear after the catalyst calcination stage, which can achieve the "pore-forming + nitrogen and carbon doping" effect, further improving the activity, selectivity and stability of the catalyst.

[0026] In some embodiments of the present invention, the co-solvent is any one of ethylene glycol, glycerol, and polyethylene glycol.

[0027] Another aspect of the present invention provides a method for preparing the acrylonitrile catalyst based on the MOF / SiO2 composite support described in the above technical solution, comprising the following steps:

[0028] S1. Add the mixed salts in the active ingredients to deionized water, heat and stir, add the multi-metal compound and transition metal oxide, rare earth precursor, MOF / SiO2 composite support and co-solvent in the active ingredients, stir, and obtain a slurry for later use.

[0029] S2. The slurry from step S1 is shaped by spray drying and calcined to obtain an acrylonitrile catalyst based on a MOF / SiO2 composite support.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The present invention selects active components composed of mixed salts, multi-metal compounds and transition metal oxides as the main components, and combines them with rare earth precursors and co-solvents. A MOF / SiO2 composite support is designed and added to prepare and synthesize an acrylonitrile catalyst based on MOF / SiO2 composite support. Through the synergistic effect between the components, it has the characteristics of high efficiency, selectivity and stability. Moreover, when applied to the preparation of acrylonitrile, it can make acrylonitrile have a high yield.

[0032] (2) In this invention, iron-based MOF materials are first synthesized by microwave hydrothermal method. The synthesized iron-based MOF materials have greater porosity, more active sites and good thermal stability, which allows the active components to be better loaded in them. In addition, the iron-based components can also play a certain role as active components. Then, 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol is introduced to modify the iron-based MOF materials, which improves the stability of the iron-based MOF materials. Finally, the MOF materials and SiO2 are mixed in a specific ratio to obtain MOF / SiO2 composite support, which has the advantages of high active sites, high specific surface area and high thermal stability, which improves the loading effect of active components in them, thereby making the acrylonitrile catalyst have the characteristics of high efficiency, selectivity and stability. Detailed Implementation

[0033] The present invention will be described below with reference to specific embodiments. It should be noted that the following embodiments are examples of the present invention and are used only to illustrate the invention, not to limit it. Other combinations and various modifications within the scope of the present invention can be made without departing from its spirit or scope.

[0034] In the following examples and comparative examples, except for the MOF / SiO2 composite support, all the other compound monomers and related reagents used were commercially available.

[0035] Preparation Example 1

[0036] The synthesis method of MOF / SiO2 composite support A includes the following steps:

[0037] (1) Add 0.03 mol FeCl3·6H2O and 0.01 mol 1,3,5-benzenetricarboxylic acid to 100 ml DMF, microwave at 200 W and 150 °C for 30 min, centrifuge, wash three times alternately with anhydrous ethanol and deionized water, dry, and obtain the product for later use.

[0038] (2) Add 10g of the product from step (1) and 4g of 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol to 100ml of a mixed solution of DMF and anhydrous ethanol (mass ratio 1:1), sonicate for 30min, heat under reflux at 100℃ for 12h, cool to room temperature, wash three times alternately with anhydrous ethanol and deionized water, and dry to obtain MOF material for later use;

[0039] (3) Mix 1.5g of MOF material from step (2) with 50g of SiO2 and ball mill to obtain MOF / SiO2 composite carrier A;

[0040] The synthesis method of SiO2 includes the following steps:

[0041] 1) Dissolve 15ml of tetraethyl orthosilicate in 50ml of ethanol, add 1.5ml of water and 2ml of 25wt% ammonia, stir well to form a silicon source solution;

[0042] 2) Add 1g of polyvinylpyrrolidone and 0.2g of sodium chloride to the silicon source solution in step 1), stir and react at 60°C for 30h, centrifuge, filter, wash with deionized water and anhydrous ethanol, and dry at 60°C to obtain SiO2.

[0043] Preparation Example 2

[0044] The synthesis method of MOF / SiO2 composite support B is the same as that of MOF / SiO2 composite support A, except that the number of moles of FeCl3·6H2O in step (1) is replaced with 0.02 mol.

[0045] Preparation Example 3

[0046] The synthesis method of MOF / SiO2 composite support C is the same as that of MOF / SiO2 composite support A, except that the mass of 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diol in step (2) is replaced with 2.5g.

[0047] Preparation Example 4

[0048] The synthesis method of MOF / SiO2 composite support D is the same as the synthesis method of MOF / SiO2 composite support A, except that the mass of MOF material in step (3) is replaced with 0.3g.

[0049] Preparation Example 5

[0050] The synthesis method of MOF / SiO2 composite support E is the same as the synthesis method of MOF / SiO2 composite support A, except that the mass of MOF material in step (3) is replaced with 3g.

[0051] Example 1

[0052] An acrylonitrile catalyst based on a MOF / SiO2 composite support, comprising the following raw materials by weight: 60 parts of active ingredient, 10 parts of rare earth precursor, 20 parts of MOF / SiO2 composite support A, 30 parts of polyethylene glycol 200, and 200 parts of deionized water.

[0053] The active ingredients include mixed salts, multi-metal compounds, and transition metal oxides;

[0054] The mixed salt is a mixture of ferric nitrate and nickel nitrate in a mass ratio of 1:0.8;

[0055] The multimetallic compound is a mixture of bismuth molybdate and bismuth ferrite in a mass ratio of 1:1;

[0056] The transition metal oxide is a mixture of cobalt oxide, nickel oxide, and manganese oxide in a mass ratio of 1:1:1.

[0057] The rare earth precursor is a mixture of cerium nitrate and lanthanum nitrate in a mass ratio of 1:1.

[0058] The preparation method of the acrylonitrile catalyst based on the MOF / SiO2 composite support in this embodiment includes the following steps:

[0059] S1. Add the mixed salts in the active ingredients to deionized water, heat to 90°C, stir for 30 min, add the multi-metal compound and transition metal oxide, rare earth precursor, MOF / SiO2 composite carrier A and polyethylene glycol in the active ingredients, stir for 2 h, and obtain the slurry for later use.

[0060] S2. The slurry from step S1 is shaped using a spray dryer (inlet temperature 180℃, outlet temperature 90℃, atomizer speed 20000rpm, tower pressure -200Pa) and calcined (at 250℃ for 3h) to obtain an acrylonitrile catalyst based on a MOF / SiO2 composite support. The specific surface area of ​​this catalyst is measured to be 45m² / g.

[0061] Example 2

[0062] An acrylonitrile catalyst based on a MOF / SiO2 composite support, comprising the following raw materials by weight: 50 parts of active ingredient, 5 parts of cerium nitrate, 15 parts of MOF / SiO2 composite support A, 20 parts of ethylene glycol, and 180 parts of deionized water.

[0063] The active ingredients include mixed salts, multi-metal compounds, and transition metal oxides;

[0064] The mixed salt is a mixture of ferric nitrate and nickel nitrate in a mass ratio of 1:0.8;

[0065] The multimetallic compound is a mixture of bismuth molybdate and bismuth ferrite in a mass ratio of 1:1;

[0066] The transition metal oxide is a mixture of cobalt oxide and nickel oxide in a mass ratio of 1:1.

[0067] The preparation method of the acrylonitrile catalyst based on the MOF / SiO2 composite support in this embodiment includes the following steps:

[0068] S1. Add the mixed salts from the active ingredients to deionized water, heat to 90°C, stir for 30 min, add the multi-metal compound and transition metal oxide, cerium nitrate, MOF / SiO2 composite carrier A and ethylene glycol from the active ingredients, stir for 2 h, and obtain the slurry for later use.

[0069] S2. The slurry from step S1 is shaped using a spray dryer (inlet temperature 180℃, outlet temperature 90℃, atomizer speed 20000rpm, tower pressure -200Pa) and calcined (at 250℃ for 3h) to obtain an acrylonitrile catalyst based on a MOF / SiO2 composite support. The specific surface area of ​​this catalyst is measured to be 42m² / g.

[0070] Example 3

[0071] An acrylonitrile catalyst based on a MOF / SiO2 composite support, comprising the following raw materials by weight: 70 parts of active ingredient, 15 parts of lanthanum nitrate, 25 parts of MOF / SiO2 composite support A, 40 parts of glycerol, and 220 parts of deionized water.

[0072] The active ingredients include mixed salts, multi-metal compounds, and transition metal oxides;

[0073] The mixed salt is a mixture of ferric nitrate and nickel nitrate in a mass ratio of 1:0.8;

[0074] The multimetallic compound is a mixture of bismuth molybdate and bismuth ferrite in a mass ratio of 1:1;

[0075] The transition metal oxide is cobalt oxide.

[0076] The preparation method of the acrylonitrile catalyst based on the MOF / SiO2 composite support in this embodiment includes the following steps:

[0077] S1. Add the mixed salts from the active ingredients to deionized water, heat to 90°C, stir for 30 min, add the multi-metal compound and transition metal oxide, lanthanum nitrate, MOF / SiO2 composite carrier A and glycerol from the active ingredients, stir for 2 h, and obtain the slurry for later use.

[0078] S2. The slurry from step S1 is shaped using a spray dryer (inlet temperature 180℃, outlet temperature 90℃, atomizer speed 20000rpm, tower pressure -200Pa) and calcined (at 250℃ for 3h) to obtain an acrylonitrile catalyst based on a MOF / SiO2 composite support. The specific surface area of ​​this catalyst is measured to be 44 m² / g.

[0079] Example 4

[0080] This embodiment provides an acrylonitrile catalyst based on a MOF / SiO2 composite support and its preparation method. The specific implementation method is the same as in Example 1, except that MOF / SiO2 composite support A is replaced by an equal amount of MOF / SiO2 composite support B.

[0081] Example 5

[0082] This embodiment provides an acrylonitrile catalyst based on MOF / SiO2 composite support and its preparation method. The specific implementation method is the same as in Example 1, except that MOF / SiO2 composite support A is replaced by MOF / SiO2 composite support C in an equal amount.

[0083] Example 6

[0084] This embodiment provides an acrylonitrile catalyst based on a MOF / SiO2 composite support and its preparation method. The specific implementation method is the same as in Example 1, except that the MOF / SiO2 composite support A is replaced by an equal amount of MOF / SiO2 composite support D.

[0085] Example 7

[0086] This embodiment provides an acrylonitrile catalyst based on a MOF / SiO2 composite support and its preparation method. The specific implementation method is the same as in Example 1, except that MOF / SiO2 composite support A is replaced by MOF / SiO2 composite support E in an equal amount.

[0087] Comparative Example 1

[0088] This comparative example provides an acrylonitrile catalyst based on a MOF / SiO2 composite support and its preparation method. The specific implementation method is the same as in Example 1, except that SiO2 is used to replace the MOF / SiO2 composite support A in equal amounts.

[0089] The preparation method for SiO2 is the same as in Example 1.

[0090] Performance testing

[0091] The acrylonitrile catalysts of Examples 1-7 and Comparative Example 1 were applied to acrylonitrile production, and the yield of acrylonitrile was tested. The wear rate of the acrylonitrile catalysts of Examples 1-7 and Comparative Example 1 was also tested. The test results are shown in Table 1.

[0092] Production of acrylonitrile:

[0093] Ⅰ: Preheat propylene, ammonia and air to 300℃ respectively, control the volume ratio of air to propylene to be 9:1 and the volume ratio of ammonia to air to be 1:9, accurately adjust the ratio of propylene, ammonia and air through a flow meter, and mix them thoroughly through a static mixer;

[0094] II: Add 50% acrylonitrile catalyst (by volume of the fluidized bed reactor) to the fluidized bed reactor, raise the temperature to 450℃ and the reaction pressure to 0.09MPa, introduce the mixed gas from step I, and control the contact time between the gas and the catalyst to 8s;

[0095] III: The reactant gas enters the quench tower, where the temperature drops rapidly to 100°C. Unreacted ammonia is neutralized by spraying with 5% dilute sulfuric acid. Then, organic compounds such as acrylonitrile, HCN, and ACN in the gas are absorbed by 10°C warm water. The absorbent is sent to the distillation section, where acrylonitrile, acrolein, and acrylic acid are obtained through azeotropic distillation and vacuum distillation.

[0096] The yield of acrylonitrile was determined by gas chromatography.

[0097] The wear rate of acrylonitrile catalysts is referenced to standard ASTM D5757.

[0098] Table 1

[0099]

[0100] The acrylonitrile catalysts in Examples 1-3 have a specific surface area of ​​about 45 m² / g, which is characterized by a high specific surface area.

[0101] As shown in Table 1, the acrylonitrile catalysts in Examples 1-3 of this invention exhibit high acrylonitrile yields in acrylonitrile synthesis, and the catalyst attenuation rates are all low, indicating that the acrylonitrile catalysts possess high activity, selectivity, and stability. Examples 4-7 involved altering the synthesis and modification of the MOF material, as well as the mixing ratio between the MOF material and SiO2, during the preparation of the MOF / SiO2 composite support. This resulted in a decrease in the stability, specific surface area, and porosity of the MOF / SiO2 composite support, consequently reducing the attenuation rate of the acrylonitrile catalyst and the acrylonitrile yield. Comparative Example 1, which used an equal amount of SiO2 to replace MOF / SiO2 composite support A, showed poor results in terms of acrylonitrile catalyst activity, selectivity, stability, and acrylonitrile yield.

[0102] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it. They should not be used to limit the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A MOF / SiO2 composite support based acrylonitrile catalyst, characterized in that, The acrylonitrile catalyst comprises the following raw materials in parts by weight: active ingredient 50-70 parts, rare earth precursor 5-15 parts, MOF / SiO2 composite carrier 15-25 parts, cosolvent 20-40 parts, and deionized water 180-220 parts; The active ingredient comprises a mixed salt, a multi-metal compound, and a transition metal oxide; The mixed salt is a mixture of iron nitrate and nickel nitrate; the multi-metal compound is a mixture of bismuth molybdate and bismuth ferrite; and the transition metal oxide comprises at least one of cobalt oxide, nickel oxide, and manganese oxide; The preparation method of the MOF / SiO2 composite carrier comprises the following steps: (1) FeCl3·6H2O and 1,3,5-benzenetricarboxylic acid are added to DMF, microwave heating is performed, centrifugation, washing, and drying are performed to obtain a product for standby use; (2) The product of step (1) and 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diphenol are added to a mixed solution of DMF and anhydrous ethanol, ultrasonic dispersion is performed, heating reflux is performed at 90-105°C for 10-13h, cooling to room temperature is performed, washing is performed, and drying is performed to obtain an MOF material for standby use; (3) The MOF material of step (2) and SiO2 are mixed, and ball milling is performed to obtain the MOF / SiO2 composite carrier.

2. The MOF / SiO2 composite support based acrylonitrile catalyst according to claim 1, characterized in that, The rare earth precursor is cerium nitrate and / or lanthanum nitrate.

3. The MOF / SiO2 composite support based acrylonitrile catalyst according to claim 1, characterized in that, In step (1), the molar ratio of FeCl3·6H2O to 1,3,5-benzenetricarboxylic acid is (2.5-3.5):

1.

4. The MOF / SiO2 composite support based acrylonitrile catalyst according to claim 1, characterized in that, In step (2), the mass ratio of the product to 4,4'-(2,2-bis(4-(pyridin-4-yl)phenyl)vinyl-1,1-diyl)diphenol is 1:(0.3-0.5).

5. The MOF / SiO2 composite support based acrylonitrile catalyst according to claim 1, characterized in that, In step (3), the mass ratio of SiO2 to the MOF material is 1:(0.01-0.05).

6. The MOF / SiO2 composite support based acrylonitrile catalyst according to claim 1, characterized in that, The cosolvent is any one of ethylene glycol, glycerol, and polyethylene glycol.

7. A process for the preparation of a MOF / SiO2 composite support based acrylonitrile catalyst according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: S1, the mixed salt in the active ingredient is added to deionized water, heated, stirred, and the multi-metal compound and the transition metal oxide in the active ingredient, the rare earth precursor, the MOF / SiO2 composite carrier, and the cosolvent are added, stirred, to obtain a slurry for standby use; S2, the slurry of step S1 is shaped by a spray dryer, and calcination is performed to obtain the MOF / SiO2 composite carrier-based acrylonitrile catalyst.

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