A method for preparing a catalyst for the hydrogenation of quinoline to decahydroquinoline and its application method.

Abstract

This invention discloses a catalyst for the hydrogenation of quinoline to decahydroquinoline, its preparation method, and its application. Nickel and copper salts are loaded onto a support via impregnation. After drying, sodium borohydride is used as a strong reducing agent in the impregnation process to ensure uniform distribution of the reducing agent within the support pores. A multi-step heat treatment sequence, including nitrogen calcination, air calcination, and hydrogen reduction, is then performed to optimize the catalyst structure. The innovations of this invention are: the use of a mesoporous silica support with the template agent not removed, simplifying the preparation process and enhancing pore stability; the impregnation reduction method ensuring uniform distribution of the reducing agent and avoiding localized over-reduction; and the multi-step heat treatment sequence effectively controlling the metal valence state and support structure. This catalyst can efficiently catalyze the hydrogenation of quinoline to decahydroquinoline in a fixed-bed reactor, exhibiting high conversion, high selectivity, and good stability.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a non-noble metal catalyst for the selective hydrogenation of quinoline to decahydroquinoline, its preparation method, and its application. More specifically, this invention relates to a method for preparing a nickel-copper alloy nanoparticle catalyst with a nitrogen-doped carbon layer coating using mesoporous silica as a support through a specific sequence of impregnation and heat treatment steps, and the application of this catalyst in catalyzing the hydrogenation reaction of quinoline in a fixed-bed reactor. Background Technology

[0002] Hydrogenation products of quinolines and their derivatives, especially decahydroquinolines (also known as perhydroquinolines), are a class of high-value-added fine chemicals. Decahydroquinolines, as an important saturated nitrogen-containing heterocyclic compound, are widely used as stabilizers for high-performance fuels, intermediates in pharmaceutical synthesis, pesticides, and solvents and catalysts in organic synthesis. Therefore, developing efficient and stable processes for the hydrogenation of quinolines to prepare decahydroquinolines has significant industrial application value.

[0003] The hydrogenation of quinoline to decahydroquinoline is a multi-step and complex reaction process, typically involving intermediates such as 1,2,3,4-tetrahydroquinoline and 5,6,7,8-tetrahydroquinoline, ultimately resulting in complete saturation of the benzene and pyridine rings. Thermodynamically, this reaction tends towards deep hydrogenation, but achieving high reaction rates, high selectivity, and long-term catalyst stability remains a key technical challenge.

[0004] Currently, catalysts for quinoline hydrogenation are mainly based on noble metals (such as Pt, Pd, and Ru) and non-noble metals (such as Ni and Co). For example, Farahanaz M. Bagwan et al. (International Journal of Hydrogen Energy, 2024, 92: 102-112) used Pd-based catalysts, and Guang-Yin Fan et al. (Catalysis Communications, 2013, 31: 81–85) used Rh-based catalysts in their research. Although noble metal catalysts have high activity, their high cost and resource scarcity limit their large-scale industrial application. In contrast, non-noble metal nickel (Ni)-based catalysts have attracted much attention due to their low cost and intrinsically high hydrogenation activity. However, traditional nickel-based catalysts have obvious limitations in practical applications: (1) Under reaction conditions, especially at high temperatures, nickel nanoparticles tend to migrate and aggregate, leading to a reduction in active sites and rapid catalyst deactivation; (2) During the hydrogenation of quinoline, intermediate products of partial hydrogenation are easily generated, making it difficult to obtain fully hydrogenated decahydroquinoline efficiently and selectively; (3) The activity of pure nickel catalysts decreases rapidly during long-term operation, failing to meet the requirements for long-term stable operation of industrial fixed-bed reactors. As reported by Anton P. Koskin et al. (Journal of Magnesium and Alloys, 2024, 12: 3245-3263), although nickel-based non-precious metal catalysts are cost-effective and have a moderate service life, their hydrogenation activity is low, with a yield of only 88-92% of decahydroquinoline at 200℃. To overcome these problems, various improvement methods have been tried in the prior art. For example, by introducing a second metal (such as copper, iron, etc.) to form an alloy with nickel, the electronic structure can be adjusted, thereby improving selectivity and anti-sintering ability. In addition, using mesoporous materials (such as mesoporous silica SBA-15, MCM-41, and HMS) as carriers, and utilizing their high specific surface area and ordered pore structure to disperse and stabilize metal nanoparticles is also an effective approach.

[0005] However, these improvements still have shortcomings. For example, supported nickel-based catalysts prepared by conventional impregnation-calcination-reduction methods often exhibit insufficient interaction between the metal particles and the support, leading to sintering under harsh reduction or reaction conditions. Furthermore, metal nanoparticles are prone to detachment or loss from the support during the reaction, affecting catalyst lifetime. In addition, precisely controlling alloy formation and constructing a coating structure on the metal particle surface that both stabilizes the particles and does not severely impede reactant diffusion are crucial for further improving catalyst performance.

[0006] Therefore, there is an urgent need in this field to develop a novel, simple, low-cost, highly active, highly selective, and excellent stable non-precious metal catalyst for the efficient hydrogenation of quinoline to decahydroquinoline, in order to meet the needs of industrial production. Summary of the Invention

[0007] The purpose of this invention is to overcome the shortcomings of non-precious metal catalysts in the hydrogenation reaction of quinoline in the prior art, such as insufficient activity, selectivity and stability, and to provide a catalyst for the hydrogenation of quinoline to prepare decahydroquinoline, its preparation method and application.

[0008] Specifically, the present invention aims to solve the following technical problems: improve the activity and selectivity of nickel-based catalysts for decahydroquinoline; enhance the anti-sintering ability and structural stability of nickel-based catalysts and extend their service life; and provide a simple and controllable preparation method to achieve precise structural control of the active center of the catalyst.

[0009] To achieve the above objectives, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a catalyst for the hydrogenation of quinoline to prepare decahydroquinoline, characterized by comprising the following steps: Step 1: Use organic amine as a template agent to synthesize mesoporous silica material, wash until neutral, dry and grind to obtain carrier sample A containing template agent; Step 2: Immerse sample A in an alcoholic solution containing nickel and copper salts, and dry to obtain sample B; the nickel salt is selected from one or more of nickel nitrate, nickel sulfate, and nickel chloride; the copper salt is selected from one or more of copper nitrate, copper sulfate, and copper chloride; the mass content of nickel is 1-15% of the carrier mass, and the mass content of copper is 1-30% of the nickel mass; Step 3: Immerse sample B in a solution containing sodium borohydride or potassium borohydride, and dry at 90-120℃ to obtain sample C; the amount of sodium borohydride or potassium borohydride used is 2-10 times the theoretical stoichiometric ratio required to reduce all metal ions; Step 4: Place sample C in a flowing inert atmosphere and treat it at 450-600℃ for 1-3 hours; then switch the atmosphere to flowing air and heat treat it at 300-400℃ for 1-3 hours; then switch the atmosphere to flowing hydrogen and reduce it at 400-500℃ for at least 1 hour; finally, cool it down in a flowing inert atmosphere to obtain the catalyst.

[0010] Preferably, the organic amine in step one is selected from dodecylamine, hexadecyltrimethylammonium bromide, or hexadecyltrimethylammonium chloride.

[0011] Preferably, the alcohol solution in step two is a methanol solution or an ethanol solution.

[0012] Preferably, in step four, the volume hourly space velocity (VHSV) of the inert atmosphere is 5-30 min. -1 The volumetric space velocity of air is 15-30 min. -1 The volume hourly space velocity (VHSV) of hydrogen is 15-30 min. -1 .

[0013] Preferably, in step four, the inert atmosphere is selected from nitrogen or argon.

[0014] In a second aspect, the present invention provides a catalyst for the hydrogenation of quinoline to prepare decahydroquinoline, characterized in that it is prepared by any one of the preparation methods described in the first aspect above.

[0015] Preferably, the catalyst comprises a mesoporous silica support and nickel-copper alloy nanoparticles coated with a nitrogen-doped carbon layer supported on the support.

[0016] Thirdly, the present invention provides the application of the above-mentioned catalyst, characterized in that the catalyst is applied in a fixed-bed reactor to catalyze the hydrogenation reaction of quinoline to prepare decahydroquinoline in the presence of hydrogen.

[0017] Preferably, the catalytic reaction is carried out at a temperature of 80-180°C, a hydrogen pressure of 0.1-4.0 MPa, and a liquid hourly space velocity (LHSV) of quinoline of 0.01-0.5 h⁻¹. -1 The molar ratio of hydrogen to quinoline is 20-50:1.

[0018] Compared with the prior art, the present invention has the following innovations: 1. Innovative Template Agent Utilization Strategy: In existing technologies, after synthesizing mesoporous supports (such as HMS and MCM-41), organic template agents are typically removed completely through high-temperature calcination or solvent extraction to obtain pure pores for metal loading. This invention intentionally retains some template agent within the mesoporous pores, creating a hydrophobic microenvironment. This design not only solves the problem of matching the hydrophilicity / hydrophobicity of the support during subsequent impregnation (using alcohol solutions), but more importantly, these residual long-chain organic amine molecules act as spatial confinement molecules within the pores, physically restricting the migration and aggregation of metal precursors or nascent nanoparticles during impregnation and subsequent reduction steps. This lays the structural foundation for achieving ultra-small sizes and high dispersion of metal nanoparticles. 2. Innovative Coupling of Low-Temperature Chemical Reduction and Atmosphere-Programmed Heat Treatment: In existing technologies, the preparation of supported metal catalysts often employs the traditional "impregnation-drying-high-temperature calcination-high-temperature hydrogen reduction" route. High-temperature processes easily lead to metal particle migration and sintering growth, reducing dispersion and the number of active sites. In this invention, step three uses a sodium / potassium borohydride solution for in-situ low-temperature chemical reduction. This method can reduce metal ions to zero valence under mild conditions, greatly suppressing particle sintering caused by high temperatures. Combined with the confinement effect of the template agent, it can form uniformly sized and highly dispersed initial metal nanoparticles. Step four employs a precision atmosphere-programmed heat treatment: "inert atmosphere pyrolysis → low-temperature air etching → hydrogen re-reduction." First, in an inert atmosphere, the residual template agent (organic amine) thermally decomposes, forming a nitrogen-doped carbon layer in situ on the surface of the metal nanoparticles. This carbon layer acts like "armor," providing protection for subsequent high-temperature processing. Subsequently, air is switched for low-temperature (300-400℃) controlled etching. This step does not completely burn off the carbon layer, but rather creates more channels and defects on the nitrogen-doped carbon layer, forming a "fragmented" or "porous" coating structure. This not only increases the specific surface area and mass transfer channels of the material, but more importantly, the metal nanoparticles coated with this type of defect-rich carbon layer have been shown in the literature to significantly enhance their dissociation and activation capabilities for hydrogen. Finally, reduction in hydrogen restores the slightly oxidized metal surface to a zero-valent active state. The entire process effectively avoids the severe sintering and loss of activity of metal particles caused by traditional high-temperature calcination. 3. Innovation in catalyst structure: This invention constructs a composite catalyst with a "nitrogen-doped carbon layer-coated ultrafine bimetallic alloy" structure. In the prior art, conventional catalysts are mostly metal particles directly exposed on the surface of the support, or only have a simple carbon layer coating, and the structure is relatively simple. They are prone to deactivation under harsh reaction conditions. This invention successfully constructs a unique composite nanostructure: ultrafine nickel-copper (Ni-Cu) alloy nanoparticles coated with porous / fragmented nitrogen-doped carbon layers are formed in the confined channels of mesoporous silica. The metal core is an ultrafine Ni-Cu alloy particle. The introduction of copper can regulate the electronic properties of nickel and weaken its strong adsorption to nitrogen-containing compounds, which may be beneficial to improving hydrogenation selectivity and preventing over-hydrogenation or cracking. The porous / fragmented nitrogen-doped carbon layer has a dual function: (1) preventing the metal core from migrating, agglomerating or directly contacting poisons in the reactants during the reaction process, significantly improving the thermal stability and anti-sintering ability of the catalyst; (2) the metal nanoparticles coated with the defect-rich carbon layer have been confirmed in the literature to significantly improve the dissociation activation ability of hydrogen. Attached Figure Description

[0019] Figure 1 TEM image of catalyst CAT-1 prepared in Example 1. Figure 2TEM image of catalyst CAT-30 prepared in Comparative Example 1. Figure 3 TEM image of catalyst CAT-31 prepared in Comparative Example 2. Figure 4 TEM image of catalyst CAT-32 prepared in Comparative Example 3. Figure 5 TEM image of catalyst CAT-33 prepared in Comparative Example 4. Detailed Implementation

[0020] To better illustrate this patent, the following embodiments are provided. These embodiments are intended to enable those skilled in the art to understand the invention in more detail, or to allow for non-essential improvements and adjustments based on the content of the invention. However, the scope of the invention is not limited to these embodiments.

[0021] Example 1 (1) Mesoporous silica (HMS) material was synthesized using dodecylamine as a template agent. After washing to neutrality, it was dried and ground to obtain a carrier sample A containing the template agent. (2) The sample A was immersed in an ethanol solution containing nickel nitrate and copper nitrate, and then dried to obtain sample B; the mass content of nickel was 5% of the mass of the carrier, and the mass content of copper was 10% of the mass of nickel. (3) Immerse the sample B in a solution containing sodium borohydride and dry it at 90°C to obtain sample C; the amount of sodium borohydride used is 5 times the theoretical stoichiometric ratio required to reduce all metal ions; (4) Sample C was placed in a flowing nitrogen atmosphere and treated at 500°C for 2 hours; then the atmosphere was switched to flowing air and heat-treated at 350°C for 2 hours; then the atmosphere was switched to flowing hydrogen and reduced at 450°C for 1 hour; finally, the sample was cooled in a flowing nitrogen atmosphere to obtain the catalyst, which was designated CAT-1; wherein the volume hourly space velocity of the nitrogen atmosphere was 10 min. –1 The volume hourly space velocity (VHSV) of the air atmosphere is 20 min. –1 The volume hourly space velocity (VHSV) of the hydrogen atmosphere was 20 min. –1 . Example 2

[0022] The preparation steps of Example 2 are the same as those of Example 1, except that the nickel content in step (2) is changed from 5% of the carrier mass to 1%, and the copper content is changed from 10% of the nickel mass. The resulting catalyst is numbered CAT-2. Example 3

[0023] The preparation steps of Example 3 are the same as those of Example 1, except that the nickel content in step (2) is changed from 5% of the carrier mass to 15%, and the copper content is changed from 10% of the nickel mass. The resulting catalyst is numbered CAT-3. Example 4

[0024] The preparation steps of Example 4 are the same as those of Example 1. The nickel content in step (2) remains unchanged at 5% of the carrier mass, and the copper content is changed from 10% of the nickel mass to 1%. The resulting catalyst is numbered CAT-4. Example 5

[0025] The preparation steps of Example 5 are the same as those of Example 1. The nickel content in step (2) remains unchanged at 5% of the carrier mass, and the copper content is changed from 10% of the nickel mass to 30%. The resulting catalyst is numbered CAT-5. Example 6

[0026] The preparation steps of Example 6 are the same as those of Example 1, except that the calcination in step (4) at 500°C under a flowing nitrogen atmosphere is changed to 450°C, and the resulting catalyst is numbered CAT-6. Example 7

[0027] The preparation steps of Example 7 are the same as those of Example 1, except that the calcination in step (4) at 500°C under a flowing nitrogen atmosphere is changed to 600°C, and the resulting catalyst is numbered CAT-7. Example 8

[0028] The preparation steps of Example 8 are the same as those of Example 1, except that the calcination of flowing air at 350°C in step (4) is changed to 300°C, and the resulting catalyst is numbered CAT-8. Example 9

[0029] The preparation steps of Example 9 are the same as those of Example 1, except that the calcination with flowing air at 350°C in step (4) is changed to 400°C, and the resulting catalyst is numbered CAT-9. Example 10

[0030] The preparation steps of Example 10 are the same as those of Example 1, except that the flow of hydrogen at 450°C in step (4) is changed to 400°C, and the resulting catalyst is numbered CAT-10. Example 11

[0031] The preparation steps of Example 11 are the same as those of Example 1, except that the flow hydrogen reduction at 450°C in step (4) is changed to 500°C, and the resulting catalyst is numbered CAT-11. Example 12

[0032] The preparation steps of Example 12 are the same as those of Example 1, except that the treatment at 500°C for 2 h in step (4) is changed to 1 h. The resulting catalyst is numbered CAT-12. Example 13

[0033] The preparation steps of Example 13 are the same as those of Example 1, except that the treatment at 500°C for 2 hours in step (4) is changed to 3 hours. The resulting catalyst is numbered CAT-13. Example 14

[0034] The preparation steps of Example 14 are the same as those of Example 1, except that the treatment at 350°C for 2 hours in step (4) is changed to 1 hour. The resulting catalyst is numbered CAT-14. Example 15

[0035] The preparation steps of Example 15 are the same as those of Example 1, except that the treatment at 350°C for 2 hours in step (4) is changed to 3 hours. The resulting catalyst is numbered CAT-15. Example 16

[0036] The preparation steps of Example 16 are the same as those of Example 1, except that the dodecylamine in step (1) is replaced with hexadecyltrimethylammonium bromide to synthesize mesoporous silica (MCM-41) material, and the resulting catalyst is numbered CAT-16. Example 17

[0037] The preparation steps of Example 17 are the same as those of Example 1, except that the dodecylamine in step (1) is replaced with hexadecyltrimethylammonium chloride to synthesize mesoporous silica (MCM-48) material, and the resulting catalyst is numbered CAT-17. Example 18

[0038] The preparation steps of Example 18 are the same as those of Example 1, except that nickel nitrate and copper nitrate in step (2) are replaced with nickel sulfate and copper sulfate, and the resulting catalyst is numbered CAT-18. Example 19

[0039] The preparation steps of Example 19 are the same as those of Example 1, except that nickel nitrate and copper nitrate in step (2) are replaced with nickel chloride and copper chloride, and the resulting catalyst is numbered CAT-19. Example 20

[0040] The preparation steps of Example 20 are the same as those of Example 1, except that the volume hourly space velocity of the nitrogen atmosphere in step (4) is 10 min. -1 Change to 5min -1 The catalyst obtained was designated CAT-20. Example 21

[0041] The preparation steps of Example 21 are the same as those of Example 1, except that the volume hourly space velocity of the nitrogen atmosphere in step (4) is 10 min. -1 Change to 30min -1 The catalyst obtained was designated CAT-21. Example 22

[0042] The preparation steps of Example 22 are the same as those of Example 1, except that the volume hourly space velocity of the air atmosphere in step (4) is 20 min. -1 Change to 15min -1 The resulting catalyst was designated CAT-22. Example 23

[0043] The preparation steps of Example 23 are the same as those of Example 1, except that the volume hourly space velocity of the air atmosphere in step (4) is 20 min. -1 Change to 30min -1 The catalyst obtained was designated CAT-23. Example 24

[0044] The preparation steps of Example 24 are the same as those of Example 1, except that the volume hourly space velocity of the hydrogen atmosphere in step (4) is 20 min. -1 Change to 15min -1 The catalyst obtained was designated CAT-24. Example 25

[0045] The preparation steps of Example 25 are the same as those of Example 1, except that the volume hourly space velocity of the hydrogen atmosphere in step (4) is 20 min. -1 Change to 30min -1 The catalyst obtained was designated CAT-25. Example 26

[0046] The preparation steps of Example 26 are the same as those of Example 1, except that the amount of sodium borohydride used in step (3) is changed from 5 times the theoretical stoichiometric ratio required to reduce all metal ions to 2 times, and the resulting catalyst is numbered CAT-26. Example 27

[0047] The preparation steps of Example 27 are the same as those of Example 1, except that the amount of sodium borohydride used in step (3) is changed from 5 times the theoretical stoichiometric ratio required to reduce all metal ions to 10 times, and the resulting catalyst is numbered CAT-27. Example 28

[0048] The preparation steps of Example 28 are the same as those of Example 1, except that the ethanol solution in step (2) is changed to a methanol solution, and the resulting catalyst is numbered CAT-28. Example 29

[0049] The preparation steps of Example 29 are the same as those of Example 1, except that the sodium borohydride solution in step (3) is replaced with potassium borohydride solution, and the resulting catalyst is numbered CAT-29. Comparative Example 1

[0050] Proving the necessity of "template retention agents" The preparation steps of Comparative Example 1 are similar to those of Example 1, except that the carrier sample A containing the template agent synthesized in step (1) is further placed in a flowing air atmosphere and treated at 600°C for 2 hours to completely remove the template agent. The resulting catalyst is numbered CAT-30. Comparative Example 2

[0051] Proving the necessity of "alcohol solution impregnation" The preparation steps of Comparative Example 2 are similar to those of Example 1, except that the ethanol solution in step (2) is replaced with deionized water, and the resulting catalyst is numbered CAT-31. Comparative Example 3

[0052] Proving the advantages of "low-temperature chemical reduction" The preparation steps of Comparative Example 3 are similar to those of Example 1, except that step (3) is removed, and the resulting catalyst is numbered CAT-32. Comparative Example 4

[0053] Demonstrating the necessity of precise design for "atmosphere-processed heat treatment" The preparation steps of Comparative Example 4 are similar to those of Example 1, except that after treating with nitrogen atmosphere at 500°C for 2 hours in step (4), the process is directly switched to hydrogen at 450°C for 1 hour, skipping the air etching step. The resulting catalyst is numbered CAT-33. Example 30: Catalyst Activity Test

[0054] The evaluation process and conditions for catalysts are as follows: (1) 6 mL of catalyst was placed in the isothermal zone of the high-pressure fixed-bed reactor and pretreated to 450 °C for 1 h under a flowing hydrogen atmosphere; wherein the volume hourly space velocity of hydrogen was 20 min. -1 ; (2) The temperature is lowered to the reaction temperature of 120°C, and the hydrogen pressure is increased to the reaction pressure of 3.0 MPa; (3) The reactants are pumped into the reactor using a pressure pump; the reactants are a 2 wt.% quinoline-cyclohexane solution; the liquid hourly space velocity of quinoline is 0.2 h⁻¹. –1 The molar ratio of hydrogen to quinoline is 50:1. (4) Use gas chromatography to perform qualitative and quantitative analysis on the products after the reaction.

[0055] The activity evaluation results of CAT-1 to CAT-33 catalysts are shown in the table below: Catalyst number Quinoline conversion rate (%) Selectivity of decahydroquinoline (%) CAT-1 100 99.9 CAT-2 67.3 10.2 CAT-3 100 74.2 CAT-4 100 98.9 CAT-5 100 96.5 CAT-6 100 50.0 CAT-7 100 84.8 CAT-8 100 87.1 CAT-9 100 91.9 CAT-10 100 99.0 CAT-11 100 97.9 CAT-12 100 89.0 CAT-13 100 94.3 CAT-14 100 94.9 CAT-15 100 91.5 CAT-16 73.6 88.3 CAT-17 82.1 90.4 CAT-18 96.2 95.6 CAT-19 98.1 93.9 CAT-20 100 91.9 CAT-21 100 99.3 CAT-22 98.4 95.6 CAT-23 98.1 98.8 CAT-24 100 98.5 CAT-25 100 99.3 CAT-26 89.4 90.3 CAT-27 97.5 96.2 CAT-28 100 83.3 CAT-29 100 87.7 CAT-30 74.6 78.3 CAT-31 63.1 83.5 CAT-32 70.3 88.4 CAT-33 100 78.9

Claims

1. A method for preparing a catalyst for the hydrogenation of quinoline to prepare decahydroquinoline, characterized in that, Includes the following steps: Step 1: Use organic amine as a template agent to synthesize mesoporous silica material, wash until neutral, dry and grind to obtain carrier sample A containing template agent; Step 2: Immerse sample A in an alcoholic solution containing nickel and copper salts, and dry to obtain sample B; the nickel salt is selected from one or more of nickel nitrate, nickel sulfate, and nickel chloride; the copper salt is selected from one or more of copper nitrate, copper sulfate, and copper chloride; the mass content of nickel is 1-15% of the carrier mass, and the mass content of copper is 1-30% of the nickel mass; Step 3: Immerse sample B in a solution containing sodium borohydride or potassium borohydride, and dry at 90-120℃ to obtain sample C; the amount of sodium borohydride or potassium borohydride used is 2-10 times the theoretical stoichiometric ratio required to reduce all metal ions; Step 4: Place sample C in a flowing inert atmosphere and treat it at 450-600℃ for 1-3 hours; then switch the atmosphere to flowing air and heat treat it at 300-400℃ for 1-3 hours; then switch the atmosphere to flowing hydrogen and reduce it at 400-500℃ for at least 1 hour; finally, cool it down in a flowing inert atmosphere to obtain the catalyst.

2. The preparation method according to claim 1, characterized in that, The organic amine in step one is selected from dodecylamine, hexadecyltrimethylammonium bromide, or hexadecyltrimethylammonium chloride.

3. The preparation method according to claim 1, characterized in that, The alcohol solution in step two is a methanol solution or an ethanol solution.

4. The preparation method according to claim 1, characterized in that, In step four, the volume hourly space velocity (VHSV) of the inert atmosphere is 5-30 min. –1 The volumetric space velocity of air is 15-30 min. –1 The volume hourly space velocity (VHSV) of hydrogen is 15-30 min. –1 .

5. The preparation method according to any one of claims 1 to 4, characterized in that, In step four, the inert atmosphere is selected from nitrogen or argon.

6. A catalyst for the hydrogenation of quinoline to prepare decahydroquinoline, characterized in that, It is prepared by any one of claims 1 to 5.

7. The catalyst according to claim 6, characterized in that, The catalyst comprises a mesoporous silica support and nickel-copper alloy nanoparticles loaded on the support and coated with a nitrogen-doped carbon layer.

8. The application of the catalyst according to any one of claims 6 and 7, characterized in that, The catalyst was applied in a fixed-bed reactor to catalyze the hydrogenation reaction of quinoline in the presence of hydrogen to prepare decahydroquinoline.

9. The application according to claim 8, characterized in that, The catalytic reaction is carried out at a temperature of 80-180℃, a hydrogen pressure of 0.1-4.0 MPa, and a liquid hourly space velocity (LHSV) of quinoline of 0.01-0.5 h⁻¹. –1 The molar ratio of hydrogen to quinoline is 20-50:1.

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