Supported metal catalysts modified with hydrophobic surface ligands, methods of making and use
By preparing a supported metal catalyst modified with hydrophobic surface ligands, the problems of low conversion and low selectivity in the fixed-bed hydrogenation reaction of halonitrobenzenes were solved, and rapid product desorption and catalyst stability were achieved, making it suitable for the continuous catalytic hydrogenation of halonitrobenzenes.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- 浙江友联化学工业有限公司
- Filing Date
- 2023-11-10
- Publication Date
- 2026-06-02
Smart Images
Figure BDA0004542650680000081 
Figure BDA0004542650680000091 
Figure BDA0004542650680000092
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalysts, specifically to a supported metal catalyst modified with hydrophobic surface ligands, its preparation method, and its application. Background Technology
[0002] Selective hydrogenation of halonitrobenzenes is a simple, economical, and effective method for synthesizing haloanilines. Currently, most domestic production methods are batch processes, which have low equipment requirements and simple operation, but suffer from drawbacks such as unsafe production processes, low production efficiency, and large amounts of waste. Continuous hydrogenation processes are safer, greener, and more efficient, representing the next generation of hydrogenation technology. However, when benzene ring molecules contain groups other than nitro (such as -Cl), most noble metal catalysts exhibit low chemoselectivity. (Applied Catalysis A, General 649(2023)118955) Excessive hydrogenation and dehalogenation can lead to the formation of acidic compounds that corrode the reactor, posing a significant challenge to large-scale industrial production. Therefore, the rational design of heterogeneous catalysts is a crucial step in achieving high selectivity. Especially in fixed-bed reactors, there are severe mass transfer problems on the catalyst particles, resulting in poor heterogeneous catalytic reaction performance and more serious dehalogenation issues.
[0003] Patent ZL108623476A achieves hydrogenation through a continuous reaction system consisting of a stirred tank reactor and a fixed bed reactor. The system includes two reaction stages: (1) the raw material undergoes a hydrogenation reaction in the stirred tank reactor; (2) the gas phase output from the stirred tank reactor enters the fixed bed reactor to continue the hydrogenation reaction, while a small amount of liquid phase is collected from the bottom of the stirred tank reactor, filtered to remove the catalyst, and also enters the fixed bed reactor to continue the hydrogenation reaction. However, this method still uses a reactor, does not fully realize continuous hydrogenation, and the process is relatively cumbersome.
[0004] Patent 112958114A employs a fixed-bed reactor, targeting the selective hydrogenation of aromatic nitro compounds. It leverages the high unsaturation of the active metal surface and the adsorption selectivity of substrate functional groups on the catalyst surface to address the control of azo condensation byproducts, thereby improving the selectivity of the target aromatic amine product and the catalyst's lifespan. However, this process uses a large amount of alkali to activate the catalyst, which easily leads to sodium ion contamination in the product, causing difficulties in subsequent separation.
[0005] Patent 109796346A uses nitro-substituted aromatic compounds as raw materials, nanoporous metal catalysts, and hydrogen as a hydrogen source to continuously hydrogenate aromatic amine products under the catalytic conditions of nanoporous palladium catalysts. Although the method is simple and the reaction conditions are mild (low temperature and low pressure), the liquid flow rate is low and the conversion rate is not high.
[0006] It is evident that the hydrogenation of fixed-bed halonitrobenzenes still suffers from problems such as low conversion rate, low product selectivity, and cumbersome hydrogenation process. Summary of the Invention
[0007] In view of this, the present disclosure provides a supported metal catalyst modified with hydrophobic surface ligands, a preparation method and an application, which at least partially solves the problems existing in the prior art.
[0008] This invention discloses a supported metal catalyst modified with hydrophobic surface ligands. The supported metal catalyst comprises a metal active component and a support. The support is a composite support consisting of molecular sieves attached to the pores of columnar activated carbon. The molecular sieves are TS-1, MCM-41, and ZSM-5, and the silica-to-alumina ratio of the molecular sieves is 20–100. The metal active component is one of platinum, palladium, ruthenium, and rhodium, and the metal loading is 0.2–5.0 wt%.
[0009] The activated carbon is made of coconut shell, walnut shell, apricot shell, or wood, and has a specific surface area of 800–2000 m². 2 / g.
[0010] This invention also discloses a method for preparing the supported metal catalyst as described above, comprising:
[0011] S1. Weigh a certain amount of activated carbon, crush and grind it appropriately, and pass it through a 10-20 mesh sieve. Add deionized water and stir to initially remove ash and other impurities from the surface of the activated carbon. After stirring, filter and dry.
[0012] S2, add a certain concentration of oxidant solution to the filtered and dried activated carbon, stir and reflux in an oil bath to remove ash and impurities from the micropores of the activated carbon, filter, wash until neutral, and dry for later use.
[0013] S3, a certain amount of molecular sieve is weighed and mixed with methanol to obtain a first mixture. Oxidized activated carbon is added to the first mixture, ultrasonicated and stirred at room temperature, filtered and dried to obtain the composite carrier.
[0014] S4. Add appropriate amounts of polyvinylpyrrolidone and ethanol to a noble metal solution of a certain concentration, and sonicate to form a uniform dispersion solution. Add the composite carrier to the metal-containing dispersion solution to obtain a second mixture. Transfer the second mixture to a hydrothermal reactor for hydrothermal treatment for several hours. After the solution cools to room temperature, filter and collect the product. Wash it several times with ethanol and water respectively, and dry it for later use.
[0015] S5, take an appropriate amount of anhydrous ethanol, slowly add the surface ligand while stirring, and then perform ultrasonic treatment; add the product generated in S4 to the solution containing the surface ligand, heat and reflux, filter, wash with ethanol several times and dry to obtain the metal catalyst.
[0016] S6, the metal catalyst is calcined in an inert gas atmosphere to obtain the final supported metal catalyst.
[0017] In step S1, the stirring temperature is 70–85°C; the stirring time is 0.5–1 h; and the solid-liquid ratio of activated carbon to deionized water is 1:5–1:10.
[0018] In step S2, the oxidant is selected from hydrogen peroxide, nitric acid, sulfuric acid and peracetic acid, preferably nitric acid or hydrogen peroxide; the concentration of the oxidant solution is 2-8 wt%; the oxidation temperature is 60-80℃; the reflux time is 1-2 h; and the solid-liquid ratio of activated carbon to oxidant is 1:5-1:15.
[0019] In step S3, the stirring time is 4-6 hours; the molecular sieve particle size is 60-100 mesh; the solid-liquid ratio of the molecular sieve to methanol is 1:10-1:50; the ultrasonic treatment is performed at room temperature for 15-30 minutes; and the mass ratio of the molecular sieve to activated carbon is preferably 5%-10%.
[0020] In step S4, the concentration of the noble metal is 10 mg / mL; the ratio of polyvinylpyrrolidone to ethanol is 1:20 to 1:50 g / mL; the ultrasonic time is 15 to 30 min; the hydrothermal temperature is 80 to 120℃, preferably 80 to 100℃; and the hydrothermal time is 4 to 8 h, preferably 4 to 6 h.
[0021] In step S5, the surface ligand is octyltrimethoxysilane, hexadecyltrimethoxysilane, or dodecanethiol; the ratio of anhydrous ethanol to the surface ligand is 5:1 to 20:1, preferably 5:1 to 10:1; the stirring time at room temperature is 10 to 30 min; the ultrasonic treatment is 30 to 60 min; the reflux temperature is 80 to 120 °C; and the reflux time is 4 to 8 h.
[0022] In step S6, the inert gas is nitrogen, argon, or helium, preferably nitrogen; the calcination temperature range under the inert gas atmosphere is 300–500°C, and the calcination time is 3–6 hours.
[0023] This invention also provides an application of the supported metal catalyst described above in a fixed-bed catalytic selective hydrogenation reaction of halonitrobenzenes to haloanilines. This reaction is a gas-liquid-solid three-phase reaction, wherein the halonitrobenzene is o-chloronitrobenzene, p-chloronitrobenzene, m-chloronitrobenzene, m-bromonitrobenzene, or p-bromonitrobenzene; it includes the following steps:
[0024] A suitable amount of quartz wool is packed into the reaction tube, a certain amount of supported metal catalyst is weighed, the supported metal catalyst is packed into the reaction tube, and a small amount of quartz sand is poured in; the ratio of the inner diameter of the reaction tube to the particle size of the supported metal catalyst is 60 to 10.
[0025] Nitrogen gas was introduced to replace the air under normal pressure, followed by hydrogen gas. After the gas flow stabilized, the supported metal catalyst was reduced. The reduction temperature was 200–350℃ and the reduction time was 2–4 hours.
[0026] After the reduction is complete, the nitrogen gas is turned off, and the hydrogen flow rate and pressure are adjusted. When the temperature drops to the reaction temperature, the raw materials are pumped into the reaction tube by a high-pressure peristaltic pump. The gas and liquid flow direction is from top to bottom and in parallel. The reaction temperature is 100-220℃, the gas-liquid ratio is 20-200, and the hydrogen pressure is 0.1-4MPa.
[0027] Compared with existing technologies, the catalyst used in this invention has the following advantages in fixed-bed continuous catalytic hydrogenation reactions:
[0028] 1) It can effectively solve the problem of rapid desorption of products (halogenated aromatic amines and water) from the catalyst surface, and avoid dehalogenation caused by excessive hydrogenation of products.
[0029] 2) Furthermore, the steric hindrance effect of the long chain of the ligand effectively prevents the accumulation of hydroxylamine intermediates.
[0030] 3) The catalyst is applicable to different halonitro compounds and has stable catalytic performance. Attached Figure Description
[0031] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0032] Figure 1 This is a TEM image of the supported metal catalyst prepared in Example 1 of the present invention. Detailed Implementation
[0033] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings.
[0034] The following specific examples illustrate the implementation of this disclosure. Those skilled in the art can easily understand other advantages and effects of this disclosure from the content disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of this disclosure, and not all of them. This disclosure can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this disclosure. It should be noted that, in the absence of conflict, the following embodiments and features in the embodiments can be combined with each other. Based on the embodiments in this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.
[0035] It should be noted that various aspects of embodiments within the scope of the appended claims are described below. It will be apparent that the aspects described herein can be embodied in a wide variety of forms, and any particular structure and / or function described herein is merely illustrative. Based on this disclosure, those skilled in the art will understand that one aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement the device and / or practice the method. Additionally, this device and / or method can be implemented using structures and / or functionalities other than one or more of the aspects set forth herein.
[0036] Furthermore, specific details are provided in the following description to facilitate a thorough understanding of the examples. However, those skilled in the art will understand that the described aspects can be practiced without these specific details. Detailed Implementation
[0038] The present invention will be described below using Examples 1 to 10 as examples. The preparation conditions of the catalysts in each example are shown in Table 1, the test results are shown in Table 2, and the specific steps of preparation and evaluation in each example are shown in Example 1. Other examples will not be described in detail.
[0039] Example 1: Pt-ZSM / AC-C8
[0040] (1) Preparation of Pt-ZSM / AC-C8 catalyst: Weigh 3.0g of coconut shell activated carbon into a 50mL beaker, add 30mL of deionized water (solid-liquid ratio 1:10), and stir in a water bath at 70℃ for 1h. After stopping stirring, filter and dry in an oven at 60℃.
[0041] After washing and drying, AC was refluxed with 15 mL of 3% nitric acid solution (solid-liquid ratio 1:5) at 80 °C with slow stirring for 1 h. It was then washed with deionized water until neutral and filtered, and dried in an oven at 60 °C.
[0042] 0.2 g of ZSM-5 molecular sieve was mixed with 10 mL of methanol and stirred. The mixture was then poured into the dried activated carbon and sonicated at room temperature for 15 min, followed by stirring at room temperature for 4 h. After filtration, the mixture was dried in an oven at 60 °C. This yielded the ZSM / AC composite support.
[0043] Weigh 0.5 g of PVP into 10 mL of ethanol and 1.5 mL of a 10 mg / mL Pt noble metal solution, sonicate for 15 min, weigh 3.0 g of composite carrier and add it to the above solution, stir at room temperature for 2 h, hydrothermally treat at 110 °C for 4 h, wash several times with ethanol and water respectively, filter and dry in an oven at 60 °C.
[0044] Take 10 ml of anhydrous ethanol and slowly add 1 mL of octyltrimethoxysilane (the ratio of anhydrous ethanol to ligand is 10:1). Sonicate for 30 min. Add the above activated carbon to the mixture and heat under reflux at 80-120℃ for 4-6 h. After filtration, wash several times with ethanol and dry in an oven at 60℃ to obtain the Pt-ZSM / AC-C8 catalyst.
[0045] (2) Evaluation of Pt-ZSM / AC-C8 catalyst: A reaction tube with an inner diameter of 1.0 cm was used. An appropriate amount of quartz wool was packed into the reaction tube. 1.5 g of catalyst with a particle size of 10–20 mesh was weighed (the ratio of the inner diameter of the reaction tube to the particle size of the catalyst was 10–20). The weighed catalyst was then packed into the reaction tube, and a small amount of quartz sand was added. Nitrogen gas was introduced to displace the air under normal pressure, followed by hydrogen gas. After the gas flow stabilized, the temperature was increased to 200 °C at a rate of 5 °C / min, and reduction was carried out for 3 hours. After the reduction was completed, the nitrogen gas was turned off, and the hydrogen pressure was adjusted to 1.0 MPa. When the temperature dropped to 160 °C and the gas-liquid ratio was 100, the raw material reaction was started.
[0046] (3) The stability results of the continuous catalytic hydrogenation of o-chloronitrobenzene by the Pt-ZSM / AC-C8 catalyst are shown in Table 3, and the TEM images are shown in Table 3. Figure 1 The pores of the molecular sieve are visible, containing Pt metal particles.
[0047] Comparative Example 1: Pt-ZSM / AC
[0048] Preparation of Pt-ZSM / AC catalyst: Weigh 3.0 g of coconut shell activated carbon into a 50 mL beaker, add 30 mL of deionized water (solid-liquid ratio 1:10), and stir in a water bath at 70 °C for 1 h. After stopping stirring, filter and dry in an oven at 60 °C.
[0049] After washing and drying, AC was refluxed with 15 mL of 3% nitric acid solution (solid-liquid ratio 1:5) at 80 °C with slow stirring for 1 h. It was then washed with deionized water until neutral and filtered, and dried in an oven at 60 °C.
[0050] 0.2 g of ZSM-5 molecular sieve was mixed with 10 mL of methanol and stirred. The mixture was then poured into the dried activated carbon and sonicated at room temperature for 15 min, followed by stirring at room temperature for 4 h. After filtration, the mixture was dried in an oven at 60 °C. This yielded the ZSM / AC composite support.
[0051] 0.5 g of PVP was weighed into 10 mL of ethanol and 1.5 mL of a 10 mg / mL Pt noble metal solution, and sonicated for 15 min. 3.0 g of composite support was weighed and added to the above solution. The mixture was stirred at room temperature for 2 h, and then hydrothermally treated at 110 °C for 4 h. The mixture was washed several times with ethanol and water, filtered, and dried in an oven at 60 °C to obtain the Pt-ZSM / AC catalyst.
[0052] (2) Evaluation of Pt-ZSM / AC catalyst: A reaction tube with an inner diameter of 1.0 cm was used. An appropriate amount of quartz wool was packed into the reaction tube. 1.5 g of catalyst with a particle size of 10–20 mesh was weighed (the ratio of the inner diameter of the reaction tube to the particle size of the catalyst was 10–20). The weighed catalyst was then packed into the reaction tube, and a small amount of quartz sand was added. Nitrogen gas was introduced to displace the air under normal pressure, followed by hydrogen gas. After the gas flow stabilized, the temperature was increased to 200 °C at a rate of 5 °C / min, and reduction was carried out for 3 hours. After the reduction was completed, the nitrogen gas was turned off, and the hydrogen pressure was adjusted to 1.0 MPa. When the temperature dropped to 160 °C and the gas-liquid ratio was 100, the raw material reaction was started.
[0053] Comparative Example 2: Pt-AC-C8
[0054] (1) Preparation of Pt-AC-C8 catalyst: Weigh 3.0 g of coconut shell activated carbon into a 50 mL beaker, add 30 mL of deionized water (solid-liquid ratio 1:10), and stir in a water bath at 70 °C for 1 h. After stopping stirring, filter and dry in an oven at 60 °C.
[0055] After washing and drying, the AC was refluxed with 15 mL of 3% nitric acid solution (solid-liquid ratio 1:5) at 80°C with slow stirring for 1 hour. It was then washed with deionized water until neutral and filtered, and dried in an oven at 60°C. This completes the pretreatment of the activated carbon.
[0056] Weigh 0.5 g of PVP into 10 mL of ethanol and 1.5 mL of 10 mg / mL Pt noble metal solution, sonicate for 15 min, weigh 3.0 g of pretreated activated carbon carrier and add it to the above solution, stir at room temperature for 2 h, hydrothermally treat at 110 °C for 4 h, wash several times with ethanol and water respectively, filter and dry in an oven at 60 °C.
[0057] Take 10 ml of anhydrous ethanol and slowly add 1 mL of octyltrimethoxysilane (the ratio of anhydrous ethanol to ligand is 10:1). Sonicate for 30 min, add the above activated carbon to the mixture, heat and reflux at 80-120℃ for 4-6 h, filter, wash several times with ethanol, and dry in an oven at 60℃ to obtain the Pt-AC-C8 catalyst.
[0058] (2) Evaluation of Pt-AC-C8 catalyst: A reaction tube with an inner diameter of 1.0 cm was used. An appropriate amount of quartz wool was packed into the reaction tube. 1.5 g of catalyst with a particle size of 10–20 mesh was weighed (the ratio of the inner diameter of the reaction tube to the particle size of the catalyst was 10–20). The weighed catalyst was then packed into the reaction tube, and a small amount of quartz sand was added. Nitrogen gas was introduced to displace the air under normal pressure, followed by hydrogen gas. After the gas flow stabilized, the temperature was increased to 200 °C at a rate of 5 °C / min, and reduction was carried out for 3 hours. After the reduction was completed, the nitrogen gas was turned off, and the hydrogen pressure was adjusted to 1.0 MPa. When the temperature dropped to 160 °C and the gas-liquid ratio was 100, the raw material reaction was started.
[0059] Table 1 Catalyst preparation conditions for Examples 1-10 and Comparative Examples 1-2
[0060]
[0061]
[0062] Table 2 Test results of Examples 1-10 and Comparative Examples 1-2
[0063]
[0064] Table 3 shows the stability results of the Pt-ZSM / AC-C8 catalyst prepared in Example 1 for the continuous catalytic hydrogenation of o-chloronitrobenzene.
[0065]
[0066]
[0067] The above description is merely a specific embodiment of this disclosure, but the scope of protection of this disclosure is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this disclosure should be included within the scope of protection of this disclosure. Therefore, the scope of protection of this disclosure should be determined by the scope of the claims.
Claims
1. A supported metal catalyst modified with hydrophobic surface ligands, characterized in that, The supported metal catalyst comprises a metal active component and a support. The support is a composite support in which molecular sieves are attached to the pores of columnar activated carbon. The molecular sieves are TS-1, MCM-41, and ZSM-5, and the silica-to-alumina ratio of the molecular sieves is 20–100. The metal active component is one of platinum, palladium, ruthenium, and rhodium, and the metal loading is 0.2–5.0 wt%. The preparation method of the supported metal catalyst is as follows: S1. Weigh a certain amount of activated carbon, crush and grind it appropriately, and pass it through a 10-20 mesh sieve. Add deionized water and stir to initially remove ash and other impurities from the surface of the activated carbon. After stirring, filter and dry. S2, add a certain concentration of oxidant solution to the filtered and dried activated carbon, stir and reflux in an oil bath to remove ash and impurities from the micropores of the activated carbon, filter, wash until neutral, and dry for later use. S3, a certain amount of molecular sieve is weighed and mixed with methanol to obtain a first mixture. Oxidized activated carbon is added to the first mixture, ultrasonicated and stirred at room temperature, filtered and dried to obtain the composite carrier. S4. Add appropriate amounts of polyvinylpyrrolidone and ethanol to a noble metal solution of a certain concentration, and sonicate to form a uniform dispersion solution. Add the composite carrier to the metal-containing dispersion solution to obtain a second mixture. Transfer the second mixture to a hydrothermal reactor for hydrothermal treatment for several hours. After the solution cools to room temperature, filter and collect the product. Wash it several times with ethanol and water respectively, and dry it for later use. S5, take an appropriate amount of anhydrous ethanol, slowly drip it into the surface ligand while stirring, and then perform ultrasonic treatment; The product generated in S4 is added to a solution containing a surface ligand, heated under reflux, filtered, washed several times with ethanol, and dried to obtain a metal catalyst; wherein the surface ligand is octyltrimethoxysilane, hexadecyltrimethoxysilane, or dodecanethiol; S6, the metal catalyst is calcined in an inert gas atmosphere to obtain the final supported metal catalyst.
2. The supported metal catalyst according to claim 1, characterized in that, The activated carbon is made of coconut shell, walnut shell, apricot shell, or wood, and has a specific surface area of 800–2000 m². 2 / g.
3. The supported metal catalyst according to claim 1, characterized in that, In step S1, the stirring temperature is 70-85℃; the stirring time is 0.5-1h; and the solid-liquid ratio of activated carbon to deionized water is 1:5-1:
10.
4. The supported metal catalyst according to claim 1, characterized in that, In step S2, the oxidant is selected from hydrogen peroxide, nitric acid, sulfuric acid and peracetic acid; the concentration of the oxidant solution is 2-8 wt%; the oxidation temperature is 60-80℃; the reflux time is 1-2 h; and the solid-liquid ratio of activated carbon to oxidant is 1:5-1:
15.
5. The supported metal catalyst according to claim 1, characterized in that, In step S3, the stirring time is 4-6 hours; the molecular sieve particle size is 60-100 mesh; the solid-liquid ratio of the molecular sieve to methanol is 1:10-1:50; the ultrasonic treatment is performed at room temperature for 15-30 minutes; and the mass ratio of the molecular sieve to activated carbon is 5%-10%.
6. The supported metal catalyst according to claim 1, characterized in that, In step S4, the concentration of the precious metal is 10 mg / mL; the ratio of polyvinylpyrrolidone to ethanol is 1:20 to 1:50 g / mL; the ultrasonic time is 15 to 30 min; the hydrothermal temperature is 80 to 120 °C; and the hydrothermal time is 4 to 8 h.
7. The supported metal catalyst according to claim 1, characterized in that, In step S5, the ratio of anhydrous ethanol to surface ligand is 5:1 to 20:1; the stirring time at room temperature is 10 to 30 min; the ultrasonic treatment is 30 to 60 min; the reflux temperature is 80 to 120 °C; and the reflux time is 4 to 8 h.
8. The supported metal catalyst according to claim 1, characterized in that, In step S6, the inert gas is nitrogen, argon, or helium; the calcination temperature range under the inert gas atmosphere is 300–500°C, and the calcination time is 3–6 hours.
9. The application of the supported metal catalyst as described in claim 1 in the fixed-bed catalytic selective hydrogenation of halonitrobenzenes to haloanilines, wherein the reaction is a gas-liquid-solid three-phase reaction, and the halonitrobenzene is o-chloronitrobenzene, p-chloronitrobenzene, m-chloronitrobenzene, m-bromonitrobenzene, or p-bromonitrobenzene; characterized in that, Includes the following steps: A suitable amount of quartz wool is packed into the reaction tube, a certain amount of supported metal catalyst is weighed, the supported metal catalyst is packed into the reaction tube, and a small amount of quartz sand is poured in; the ratio of the inner diameter of the reaction tube to the particle size of the supported metal catalyst is 60 to 10. Nitrogen gas was introduced to replace the air under normal pressure, followed by hydrogen gas. After the gas flow stabilized, the supported metal catalyst was reduced. The reduction temperature was 200–350℃ and the reduction time was 2–4 hours. After the reduction is complete, turn off the nitrogen gas and adjust the hydrogen flow rate and pressure. When the temperature drops to the reaction temperature, use a high-pressure peristaltic pump to pump the raw materials into the reaction tube. The gas and liquid flow direction is from top to bottom in parallel. The reaction temperature is 100–220℃, the gas-liquid ratio is 20–200, and the hydrogen pressure is 0.1–4 MPa.