Nitro hydrogenation catalyst, preparation method thereof and catalytic hydrogenation preparation method of aniline compound

Abstract

The invention provides a nitro hydrogenation catalyst, a preparation method thereof and a catalytic hydrogenation preparation method of aniline compounds. The preparation method comprises the following steps: preparing a zirconium source solution from a zirconium source, a first acid agent and water, and adding a first precipitator into the zirconium source solution to obtain a mixed solution A; preparing a cerium source, a second acid agent and water into a mixed solution B, and adding the mixed solution B and a second precipitator into the mixed solution A to obtain a mixed solution C; carrying out hydrothermal reaction on the mixed solution C to obtain a carrier precursor; calcining the carrier precursor to obtain a composite carrier; preparing the composite carrier and water into first slurry, adding a nickel source into the first slurry, and mixing to obtain second slurry; and adding a boron source and a phosphorus source into the second slurry, and stirring for reaction to obtain the nitro hydrogenation catalyst. The preparation method comprises the following steps: preparing the composite zirconium-cerium carrier, reducing the nickel source through the boron source and the phosphorus source, and depositing on the obtained composite zirconium-cerium carrier to obtain the nitro hydrogenation catalyst with excellent performance.

Description

Technical Field

[0001] The present invention relates to the field of organic synthesis, and in particular, to a nitro-hydrogenation catalyst, a preparation method thereof, and a catalytic hydrogenation method for preparing aniline compounds. Background Art

[0002] Aniline derivatives are an important class of fine chemical intermediates and are widely used as raw materials in the production of chemicals such as pharmaceuticals, pesticides, rubber, and dyes. Industrially, aniline compounds are often prepared by the reduction of nitroarenes, generally including iron powder reduction method, sulfide reduction method, electrochemical reduction method, transfer hydrogenation method, and catalytic hydrogenation method, etc. Among them, the catalytic hydrogenation method uses hydrogen as a reducing agent and has excellent economy and environmental friendliness, and is a commonly used means for preparing aniline industrially. Common catalysts for nitro-hydrogenation are mainly Raney nickel, noble metals such as palladium, platinum, ruthenium, and nickel-based catalysts with zirconium silicate or alumina as carriers, etc.

[0003] In recent years, with the development of catalytic science, various catalysts for the hydrogenation reaction of nitro compounds have emerged. The invention with patent number CN117983210 A provides a catalyst for synthesizing o-phenylenediamine from o-nitroaniline. By modifying activated carbon and loading palladium and platinum metals, the catalytic performance is improved. However, this method still uses noble metals, has a high cost, and the modification process of the carrier is relatively complex, making it difficult to carry out large-scale industrial production. The invention with patent number CN115709102 A proposes a bimetallic nickel ruthenium catalyst, which is prepared by impregnation and calcination based on a silica / alumina composite carrier. This catalyst shows excellent stability in the nitro-hydrogenation reaction, but its preparation process is complex, and the use of ruthenium metal also increases the cost. In the invention with patent number CN115414940 A, a carbon-based metal catalyst is synthesized through a hydrothermal method and a heat treatment process. Although the catalyst prepared by this method has certain catalytic activity, the preparation of its carrier and the metal loading process involve multiple chemical reactions, and the operating conditions are harsh, which is not conducive to continuous production. The invention with patent number CN112569943A describes a nickel-based benzene hydrogenation catalyst, which uses alumina and silica as a two-component carrier and is prepared by a co-precipitation-impregnation method. Although this catalyst shows good performance in the nitro-hydrogenation reaction, the acidity of the carrier is single, and the interaction force between the active component and the carrier is weak, which limits the performance and service life of the catalyst to a certain extent.

[0004] Generally speaking, current catalytic technologies, especially non-noble metal catalytic materials for the hydrogenation reaction of nitro compounds, although progress has been made in some aspects, there are still some key problems to be solved:

[0005] First, precious metals are expensive and are mostly used in batch autoclave nitrohydrogenation reactions. They are prone to poisoning and do not have the conditions for continuous operation.

[0006] Second, nickel-based catalysts with alumina and zirconium silicate as carriers have certain limitations in the depth of hydrogenation. Moreover, the acidity of their carriers is single, and the interaction between the active component and the carrier is relatively weak, resulting in poor catalytic effects.

[0007] Third, although some crystalline catalytic materials with unique structures and properties have emerged, most of them have fewer surface active sites and poor stability, resulting in poor catalyst performance and being not conducive to long-term use and industrialization.

[0008] Based on this, how to develop a new catalyst system for the hydrogenation of nitroaromatic compounds, which can not only significantly reduce production costs and simplify the production process, but also be applicable to the continuous production process while maintaining the high efficiency and selectivity of the reaction, is one of the important technical problems to be solved in this field. Summary of the Invention

[0009] The main object of the present invention is to provide a nitrohydrogenation catalyst, a preparation method thereof, and a catalytic hydrogenation preparation method of aniline compounds, so as to solve the problem that the existing catalyst system cannot achieve the catalytic hydrogenation of nitroaromatic compounds to prepare aniline compounds with high conversion rate and high selectivity.

[0010] To achieve the above object, the first aspect of the present invention provides a preparation method of a nitrohydrogenation catalyst, including: Step S1, preparing a zirconium source solution by mixing a zirconium source, a first acid agent, and water, and adding a first precipitating agent to the zirconium source solution to obtain a mixed solution A with a pH of 8.5 - 9.0; Step S2, preparing a mixed solution B by mixing a cerium source, a second acid agent, and water, and adding the mixed solution B and a second precipitating agent to the mixed solution A to obtain a mixed solution C with a pH of 6.8 - 7.2; Step S3, subjecting the mixed solution C to a hydrothermal reaction to obtain a carrier precursor; the carrier precursor is subjected to a calcination treatment to obtain a composite carrier; Step S4, preparing a first slurry by mixing the composite carrier and water, and adding a nickel source to the first slurry, and obtaining a second slurry after mixing; Step S5, adding a boron source and a phosphorus source to the second slurry and stirring and reacting under the condition of 0 ± 5 °C, so that the boron source, the phosphorus source, and the nickel source are deposited on the composite carrier to form an amorphous alloy, thereby obtaining a nitrohydrogenation catalyst.

[0011] Further, the molar ratio of the zirconium source to the cerium source is 1:(0.2 - 0.5); and / or, the zirconium source is selected from one or more of zirconium nitrate, zirconium oxychloride, zirconium acetate, zirconium sulfate, zirconium carbonate, and zirconium chloride; and / or, the cerium source is selected from one or more of cerium nitrate, cerium chloride, and cerium acetate.

[0012] Further, denote the total molar amount of the zirconium source and the cerium source as M1, and denote the total molar amount of the first acid agent and the second acid agent as M2, where M2:M1 = 1:(75 - 95); and / or, the first acid agent and the second acid agent are each independently selected from one or more of citric acid, oxalic acid, acetic acid, and nitric acid, and both the first acid agent and the second acid agent are added in the form of an acid solution with a molar concentration of 0.08 M to 0.1 M; and / or, the first precipitating agent and the second precipitating agent are each independently selected from one or more of sodium hydroxide, sodium carbonate, and ammonia water.

[0013] Further, in step S3, the reaction temperature of the hydrothermal reaction is 120°C to 150°C, and the time is 8 h to 12 h; and / or, the calcination temperature of the calcination treatment is 300°C to 400°C, and the calcination treatment is carried out in an inert atmosphere.

[0014] Further, in step S4, the weight ratio of the nickel source to the composite support is (0.6 - 1.12):1; and / or, the mixing is stirring mixing, and the stirring mixing time is 0.5 h to 1 h; and / or, the nickel source is selected from one or more of nickel nitrate, nickel sulfate hexahydrate, and nickel chloride.

[0015] Further, in step S5, the molar ratio of the boron source to the phosphorus source is 1:(1.5 - 2); and / or, the molar amount of the nickel source to the total molar amount of the boron source and the phosphorus source is 1:(2.8 - 4.0); the boron source is selected from one or more of KBH4, NaBH4, and (CH3COO)3BHNa; and / or, the phosphorus source is selected from one or more of NaH2PO2, H3PO2, and H6NO3P; and / or, the addition method of the boron source and the phosphorus source is dropwise addition, and during the dropwise addition process, step S5 further includes adding an alkali solution to the second slurry to keep the pH of the second slurry at 12 ± 0.2; the alkali solution is selected from one or more of sodium hydroxide solution, sodium carbonate solution, and ammonia water.

[0016] The second aspect of the present invention provides a nitro-hydrogenation catalyst, which is prepared by the preparation method of the above nitro-hydrogenation catalyst.

[0017] The third aspect of the present invention provides a catalytic hydrogenation preparation method of an aniline compound. The nitroaromatic compound and hydrogen are subjected to a hydrogenation reaction under the action of the above nitro-hydrogenation catalyst to obtain an aniline compound.

[0018] Further, before the hydrogenation reaction, the catalytic hydrogenation preparation method of the aniline compound further includes loading the nitro-hydrogenation catalyst into a fixed bed and performing an activation treatment. The activation treatment includes: under a hydrogen atmosphere, heating at a heating rate of 10 ± 2°C / min to 100°C to 150°C, and holding for 2 h to 3 h.

[0019] Further, in the hydrogenation reaction, the feeding rate of the nitroaromatic compound is 1.0 ± 0.2 g / min; the feeding rate of hydrogen is 20 mL / min to 30 mL / min; and the reaction temperature is 50°C to 60°C.

[0020] By applying the technical solution of the present invention, a composite zirconium-cerium support is prepared by a precipitation method in a specific order. Then, through a boron source and a phosphorus source, a nickel source is reduced and deposited on the obtained composite zirconium-cerium support, and a nitro-hydrogenation catalyst with excellent performance is obtained. In the structure of the obtained catalyst, an interaction can occur between the support and the active component, avoiding the shedding of the active component, improving the adhesion of the active component, thereby causing an increase in its catalytic activity and selectivity, and prolonging its service life. Finally, the catalyst prepared by the present invention and having a nano-amorphous Ni-B / P component can continuously catalyze the hydrogenation of nitroaromatic compounds in a fixed bed under relatively mild conditions, improving its production conditions, and showing a high conversion rate and aniline product selectivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings forming a part of this application are used to provide a further understanding of the present invention. The schematic embodiments and descriptions thereof of the present invention are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0022] Figure 1 It is a liquid-phase test result diagram obtained from Application Example 3. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] It should be noted that, without conflict, the embodiments in this application and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the embodiments.

[0024] As described in the background art, the catalyst system in the prior art has the problem that the catalytic hydrogenation of nitroaromatic compounds to prepare aniline compounds cannot be achieved with high conversion and high selectivity. To solve the above technical problems, a first aspect of the present invention provides a method for preparing a nitro-hydrogenation catalyst, including: Step S1, formulating a zirconium source solution by mixing a zirconium source, a first acid agent, and water, and adding a first precipitating agent to the zirconium source solution to obtain a mixed solution A with a pH of 8.5-9.0; Step S2, formulating a mixed solution B by mixing a cerium source, a second acid agent, and water, and adding the mixed solution B and a second precipitating agent to the mixed solution A to obtain a mixed solution C with a pH of 6.8-7.2; Step S3, subjecting the mixed solution C to a hydrothermal reaction to obtain a support precursor; the support precursor is calcined to obtain a composite support; Step S4, formulating a first slurry by mixing the composite support and water, and adding a nickel source to the first slurry, and obtaining a second slurry after mixing; Step S5, under the condition of 0±5°C, adding a boron source and a phosphorus source to the second slurry and stirring and reacting to deposit the boron source, the phosphorus source, and the nickel source on the composite support to form an amorphous alloy, thereby obtaining a nitro-hydrogenation catalyst.

[0025] The present invention prepares a composite zirconium-cerium support by a precipitation method. Then, through a boron source and a phosphorus source, the nickel source is reduced and deposited on the obtained composite zirconium-cerium support, and a nitro-hydrogenation catalyst with excellent performance is obtained. Specifically, in Step S1, a zirconium source solution is formulated by mixing a zirconium source, a first acid agent, and water. Then, zirconium ions react with a first precipitating agent to form a zirconium-based precursor with a specific morphology and pore size. Subsequently, a cerium source, a second acid agent, and water are mixed to form a mixed solution B. When the mixed solution B and the cerium source are added to the mixed solution A with the pH value adjusted together, the deposition of cerium ions on the surface of the zirconium-based precursor is uniform and gradually transitions from a low cerium content region to a high cerium content region, finally forming a cerium-rich surface layer. This process not only increases the electronic activity of the composite support but also promotes the formation of oxygen vacancies, providing abundant active sites for the deposition of subsequent active components. Subjecting the mixed solution C to a hydrothermal reaction promotes the fusion of zirconium-cerium oxide particles, enhances the stability of the material, and at the same time retains the gradient characteristics of the transition layer, further optimizing the structure of the zirconium-cerium composite support to be formed, making it form a more compact ZrO2 / CeO2 composite material under high temperature and high pressure conditions, creating a stable support with abundant active sites for the deposition of subsequent amorphous alloys.

[0026] Then, in Step S4, through physical mixing, nickel ions are uniformly distributed on the surface of the obtained composite support. Finally, in Step S5, based on the low temperature (0±5°C) condition, a boron source and a phosphorus source are added and stirred and reacted. Boron and phosphorus react with nickel ions as reducing agents to form an amorphous Ni-B / P alloy.

[0027] Moreover, in this step, low-temperature conditions are selected for the deposition of the alloy, which avoids the formation of crystalline phases and makes the alloy exhibit a state of short-range order and long-range disorder. On the one hand, this structural characteristic increases the surface free energy of the material and generates more active sites; on the other hand, the electron interaction between B / P atoms and metal Ni atoms makes Ni in a rich electron state, while B / P atoms are in an electron-deficient state. This difference in electron structure contributes to the different adsorption abilities of the catalyst for N and O atoms in nitro compounds, enhancing the selectivity and activity of the catalyst for the nitro hydrogenation reaction.

[0028] In summary, the above preparation method provided by the present invention precisely controls the structure of the zirconium-cerium composite support through sequential precipitation reactions, and combined with the low-temperature deposition of the amorphous alloy, a nitro hydrogenation catalyst with a unique microstructure is constructed. In the structure of the obtained catalyst, the Zr-Ce oxide composite support and the gradually changing transition layer structure of cerium content thereon enable the catalyst to have a gradient distribution of electronic properties and active sites from the core to the surface. This structural characteristic is beneficial to improving the adaptability of the catalyst to different reactants and the catalytic efficiency, while avoiding the problem of shedding of active components caused by uneven distribution of cerium and zirconium in the traditional co-precipitation method.

[0029] In particular, the cerium-rich surface in the composite support is rich in oxygen vacancies, which can significantly enhance the adsorption ability of the catalyst for nitro compounds, facilitate the stable adsorption and activation of reactants on the catalyst surface, and improve the selectivity and efficiency of the hydrogenation reaction. At the same time, the redox characteristics of cerium combined with the stable framework of the inner core ZrO2 provide a good electronic environment for the catalyst. The electron-rich characteristics of CeO2 can promote the transfer of electrons from reactants to the catalyst, enhancing the activation of reactants, while the stable framework of ZrO2 supports this process, ensuring the long-term stability of the catalyst.

[0030] Moreover, in the above preparation method, the amorphous Ni-B / P alloy is essentially nanoscale, and can be controlled as low as 3 to 5 nm. Its deposition on the cerium-rich surface significantly increases the density of active sites of the catalyst, and at the same time, through the synergistic effect of B / P elements and Ni, improves the dissociation adsorption ability of the catalyst for hydrogen and the deep hydrogenation ability for nitro compounds. That is to say, the catalyst with the above amorphous structure has rich active sites and strong electron mobility, can effectively accelerate the nitro hydrogenation reaction, and at the same time maintain high selectivity and long-term stability.

[0031] Furthermore, the molar ratio of the zirconium source to the cerium source is 1:(0.2 - 0.5). Under such molar amount conditions, it is more conducive to the preferential deposition of cerium ions on the surface of ZrO2 particles. Due to the reduction properties of cerium ions and their easy conversion characteristics between different valence states, they will form a more stable transition layer with gradually increasing cerium content on the surface of the zirconium-based material, thereby more significantly enhancing the adsorption capacity of the catalyst for nitro compounds.

[0032] In several typical embodiments, the zirconium source is selected from one or more of zirconium nitrate, zirconyl chloride, zirconium acetate, zirconium sulfate, zirconium carbonate, and zirconium chloride; and / or, the cerium source is selected from one or more of cerium nitrate, cerium chloride, and cerium acetate. The above zirconium-cerium sources can more effectively optimize the reaction conditions, improve the reaction efficiency, and the finally formed composite support has a better pore structure and a higher density of active sites.

[0033] In order to further improve the uniformity and stability of the obtained composite support, let the total molar amount of the zirconium source and the cerium source be M1, and let the total molar amount of the first acid agent and the second acid agent be M2, M2:M1 = 1:(75 - 95). Specifically, a more suitable amount of the acid agent can promote the formation of a material with a highly stable and uniform structure during the hydrothermal treatment of the composite support precursor. At the same time, the above amount of the acid agent can provide a better buffering effect, enabling the deposition rate and depth of cerium ions on the ZrO2 surface to be more precisely controlled, forming a special structure of a cerium content gradient transition layer from the core to the surface, and finally optimizing the activity of the obtained catalyst.

[0034] Moreover, during the specific use process, the first acid agent and the second acid agent are each independently selected from one or more of citric acid, oxalic acid, acetic acid, and nitric acid, and both the first acid agent and the second acid agent are added in the form of an acid solution with a molar concentration of 0.08M - 0.1M.

[0035] Moreover, preferably, the first precipitating agent and the second precipitating agent are each independently selected from one or more of sodium hydroxide, sodium carbonate, and ammonia water. More preferably, in a dropping manner, the mixed solution B and the second precipitating agent are added to the mixed solution A under the condition of 40°C - 50°C. Mixing the solution containing the zirconium source and the cerium source within a suitable temperature range while carrying out the precipitation reaction can further optimize the porosity and surface area of the obtained support, providing more active sites for the subsequent deposition of the amorphous alloy.

[0036] In step S3, the reaction temperature of the hydrothermal reaction is 120°C to 150°C, and the time is 8h to 12h. The temperature and time of the above hydrothermal reaction promote the uniform growth of zirconium cerium oxide grains, thereby further enhancing the bonding strength between the amorphous alloy and the support. Subsequently, the calcination temperature of the preferred calcination treatment is 300°C to 400°C, and the calcination treatment is carried out in an inert atmosphere, thereby further enhancing the thermal stability of the obtained composite support, promoting the formation of oxygen vacancies on the support surface, and enhancing the activity and stability of the obtained catalyst.

[0037] Furthermore, in step S4, the weight ratio of the nickel source to the composite support is preferably (0.6 to 1.12):1. This preferred weight ratio more significantly promotes the strong interaction between the metal active component nickel and the support. Especially when the support contains oxygen vacancies, the oxygen vacancies at the interface of nickel nanoparticles can significantly enhance the adsorption capacity of the catalyst for reactants, accelerate the charge transfer and activation process, and ultimately improve the efficiency of the catalytic hydrogenolysis reaction, especially for the cleavage of the N-O bond, thereby realizing the more efficient progress of the nitro-hydrogenation reaction. In order to make the nickel source and the composite support contact and disperse more fully, stirring and mixing are preferably used, and the stirring and mixing time is 0.5h to 1h. In practical applications, the nickel source can be selected from one or more of nickel nitrate, nickel sulfate hexahydrate, and nickel chloride.

[0038] In step S5, the molar ratio of the boron source to the phosphorus source is preferably 1:(1.5 to 2); and / or, the molar amount of the nickel source to the total molar amount of the boron source and the phosphorus source is 1:(2.8 to 4.0). By optimizing the molar ratios of boron, phosphorus, and nickel, the structure of the catalyst can be further optimized. The B and P elements are evenly distributed in the amorphous alloy, forming an electronic environment with a synergistic effect, enabling the obtained catalyst to have a more stable electronic state and spatial configuration, achieving efficient cleavage of the N-O bond in the nitro-hydrogenation reaction, while reducing the occurrence of over-hydrogenation side reactions and improving the production purity and selectivity of aniline derivatives.

[0039] In several typical embodiments, the boron source is selected from one or more of KBH4, NaBH4, and (CH3COO)3BHNa; and / or, the phosphorus source is selected from one or more of NaH2PO2, H3PO2, and H6NO3P. Among them, especially when the boron source is KBH4 and the phosphorus source is NaH2PO2, KBH4, as a strong reducing agent, can more quickly reduce nickel salts to metallic nickel, while introducing boron elements into the catalyst structure; NaH2PO2 can adjust the electronic environment of the catalyst by introducing phosphorus elements, further improving its activity and selectivity.

[0040] Furthermore, it is preferred that the boron source and the phosphorus source are added dropwise. During the dropping process, step S5 further includes adding an alkali solution to the second slurry to keep the pH of the second slurry at 12 ± 0.2. This preferred pH regulation, combined with the dropping method, can minimize the agglomeration during the precipitation of each element to a greater extent, promote the uniform distribution of the active components, and finally form a catalyst with higher activity and high selectivity, improving the yield and purity of aniline derivative products. In practical applications, the alkali solution can be selected from one or more of sodium hydroxide solution, sodium carbonate solution, and ammonia water. Preferably, the molar concentrations of the sodium hydroxide solution and the sodium carbonate solution are each independently 2 ± 0.2 M; the mass concentration of ammonia water is 30 ± 5%.

[0041] The second aspect of the present invention provides a nitro-hydrogenation catalyst, which is prepared by the preparation method of the above nitro-hydrogenation catalyst. The catalyst prepared by the present invention has a unique structure with short-range order and long-range disorder, so it has more active sites and stronger electron transfer ability than traditional crystalline catalysts. At the same time, the existence of oxygen vacancies not only enhances the adsorption of reactants by the catalyst, but also promotes charge transfer and the activation of reactants. Especially in the hydrogenation reaction of nitro compounds, it plays a decisive role in promoting the cleavage of the N-O bond.

[0042] It should be particularly noted that due to the particularity of the material field and the limitations of existing testing and characterization methods, it is difficult to comprehensively and quantitatively characterize the complex crystal structure and microstructure of the above-obtained catalyst. However, the performance test results show that the catalyst obtained in this application has more excellent catalytic hydrogenation performance, especially suitable for the reaction process of catalytic hydrogenation of nitroaromatic compounds to prepare aniline compounds.

[0043] The third aspect of the present invention provides a method for catalytic hydrogenation preparation of aniline compounds. The nitroaromatic compounds and hydrogen are subjected to a hydrogenation reaction under the action of the above nitro-hydrogenation catalyst to obtain aniline compounds. The above catalyst obtained by the present invention can achieve effective adsorption and activation of reactants through the synergistic effect of oxygen vacancies and basic sites on the surface of the composite support and the amorphous Ni-B / P alloy in the hydrogenation reaction of nitroaromatics. In particular, the active sites on the catalyst surface can efficiently promote the electron transfer between the nitro group and hydrogen, accelerate the cleavage of the N−O bond, and at the same time inhibit possible side reactions such as over-hydrogenation and alkylation, ensuring the high-selectivity generation of the final aniline compounds.

[0044] Further, before the hydrogenation reaction, the catalytic hydrogenation preparation method of aniline compounds further includes loading a nitro-hydrogenation catalyst into a fixed bed and performing an activation treatment, and the activation treatment includes: under a hydrogen atmosphere, heating to 100°C to 150°C at a heating rate of 10±2°C / min, and maintaining the temperature for 2h to 3h. During this process, the oxygen vacancies on the surface of the nitro-hydrogenation catalyst can react with hydrogen in advance to form more active hydrogen species, so as to more effectively participate in the subsequent hydrogenation reaction and promote the conversion of nitro compounds.

[0045] In several typical embodiments, in the hydrogenation reaction, the feeding rate of the nitroaromatic compound is 1.0±0.2g / min; the feeding rate of hydrogen is 20mL / min to 30mL / min; the reaction temperature is 50°C to 60°C. Under the preferably selected conditions, the active sites of the catalyst can fully contact the fed nitroaromatic and hydrogen, and its activity and stability can be more fully exerted, so as to achieve a more efficient and highly selective hydrogenation reaction of nitroaromatic.

[0046] The following further describes the present application in detail with specific embodiments, and these embodiments should not be construed as limiting the scope claimed by the present application.

[0047] Unless otherwise defined, all the technical terms used hereinafter have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are only for the purpose of describing specific embodiments, and are not intended to limit the protection scope of the present invention.

[0048] Example 1

[0049] A preparation method of a nitro-hydrogenation catalyst:

[0050] (1) Add 33.9g (0.1mol) of zirconium nitrate to 10mL of a citric acid solution with a concentration of 0.08M (where the molar amount of citric acid is 0.0008mol) and 100mL of purified water, and dissolve to obtain a zirconium source solution; at 40°C, add a sodium hydroxide precipitant with a concentration of 1M to the zirconium source solution until the pH reaches 8.7 to obtain a mixed solution A.

[0051] (2) Dissolve 6.5 g (0.02 mol) of cerium nitrate (i.e., the molar ratio of zirconium source to cerium source is 1:0.2) in 150 mL of purified water, and then add 10 mL of a citric acid solution with a concentration of 0.08 M (where the molar amount of citric acid is 0.0008 mol) to obtain a mixed solution B. Flow the prepared sodium hydroxide precipitant solution with a concentration of 1 M and the mixed solution B in parallel, and add them dropwise to the mixed solution A. Under the condition of 40 °C, control the dropping time to be 0.5 h and keep the pH at 6.8 to obtain a mixed solution C. Among them, the ratio of the total molar amount of citric acid to the total molar amount of zirconium source and cerium source is 1:75.

[0052] (3) Transfer the mixed solution C to a hydrothermal reactor, and carry out hydrothermal reaction at 120 °C for 12 h to obtain a composite catalyst support after filtration, and then dry it at 90 °C for 24 h. The dried solid is calcined under the protection of nitrogen inert gas at 300 °C to obtain a composite support.

[0053] (4) In a four-necked flask, add 500 mL of purified water, and add 30 g of the composite support at room temperature. After stirring evenly, obtain the first slurry. Then add 18.6 g (0.102 mol) of nickel nitrate (i.e., the weight ratio of nickel source to composite support is 0.62:1) to it, and stir for 0.5 h to obtain the second slurry.

[0054] (5) Cool the second slurry to 0 °C by circulating water bath, and dropwise add a solution of 5.5 g (0.1 mol) KBH4 and a solution of 17.6 g (0.2 mol) NaH2PO2 under stirring. During this process, adjust the pH = 12 with 2 M sodium hydroxide solution. Among them, the molar ratio of boron source to phosphorus source is 1:2; the molar amount of nickel source to the total molar amount of boron source and phosphorus source is 1:2.9. After the dropping is completed, stop the reaction when no gas is released, filter, collect the black precipitate by suction filtration, wash the black precipitate repeatedly with deionized water until the pH = 7, then wash it twice with absolute ethanol, and dry the obtained product in a vacuum drying oven at 60 °C for 8 h to obtain a nitro-hydrogenation catalyst.

[0055] Example 2

[0056] A preparation method of a nitro-hydrogenation catalyst:

[0057] (1) Add 32.2 g (0.1 mol) of zirconyl chloride to 5 mL of an oxalic acid solution with a concentration of 0.08 M (the molar amount of oxalic acid is 0.0004 mol) and 100 mL of purified water, and dissolve to obtain a zirconium source solution; at 40 °C, dropwise add a sodium hydroxide precipitant solution with a concentration of 1 M to this zirconium source solution until the pH is 9.0 to obtain a mixed solution A.

[0058] (2) Dissolve 12.3 g (0.05 mol) of cerium chloride (i.e., zirconium source: cerium source = 1:0.5, molar ratio) in 150 mL of purified water, then add 15 mL of oxalic acid solution with a concentration of 0.08 M (the molar amount of oxalic acid is 0.0012 mol) to obtain mixture B. At the same time, flow the prepared sodium hydroxide precipitant solution with a concentration of 1 M and mixture B in parallel, and add them dropwise to mixture A. Under the condition of 50 °C, control the dropping time to be 1 h and keep the pH at 7.2 to obtain mixture C. Among them, the molar ratio of oxalic acid to the total molar amount of zirconium source and cerium source is 1:94.

[0059] (3) Transfer mixture C to a hydrothermal reactor, react and keep warm at 150 °C for 8 h to carry out hydrothermal reaction, filter to obtain a composite catalyst support, dry it at 100 °C for 12 h, and calcine the dried solid under the protection of nitrogen inert gas at 400 °C to obtain a composite support.

[0060] (4) In a four-necked flask, add 500 mL of purified water, and add 30 g of the composite support at room temperature. After stirring evenly, obtain the first slurry. Then add 33.6 g (0.1279 mol) of nickel sulfate hexahydrate (i.e., nickel source: composite support = 1.12:1, weight ratio) to it, and stir for 1 h to obtain the second slurry.

[0061] (5) Cool the second slurry to 0 °C by circulating water bath, and dropwise add a solution of 8.6 g (0.16 mol) of KBH4 and a solution of 21.11 g (0.24 mol) of NaH2PO2 dropwise under stirring. During this process, adjust the pH = 12 with 2 M sodium carbonate solution. Among them, the molar ratio of boron source and phosphorus source is 1:1.5; the molar amount of nickel source to the total molar amount of boron source and phosphorus source is 1:3.13. After the dropping is completed, stop the reaction when no gas is released, filter, collect the black precipitate by suction filtration, wash the black precipitate repeatedly with deionized water until the pH = 6.8, then wash it twice with absolute ethanol, and dry the obtained product in a vacuum drying oven at 80 °C for 6 h to obtain a nitro-hydrogenation catalyst.

[0062] Example 3

[0063] A preparation method of a nitro-hydrogenation catalyst:

[0064] (1) Add 32.2 g (0.1 mol) of zirconyl chloride to 10 mL of citric acid solution with a concentration of 0.08 M (the molar amount of citric acid is 0.0008 mol) and 100 mL of purified water, and dissolve to obtain a zirconium source solution; dropwise add a 30% ammonia precipitant solution to the zirconium source solution at 50 °C until the pH is 8.5 to obtain mixture A.

[0065] (2) Dissolve 12.3 g (0.05 mol) of cerium chloride (i.e., zirconium source: cerium source = 1:0.5, molar ratio) in 150 mL of purified water, then add 10 mL of oxalic acid solution with a concentration of 0.08 M (the molar amount of oxalic acid is 0.0008 mol) to obtain a mixed solution B. At the same time, flow the prepared 30% ammonia precipitant and the mixed solution B in parallel and add them dropwise to the mixed solution A. Under the condition of 50 °C, control the dropping time to be 0.8 h and keep the pH at 7.0 to obtain a mixed solution C. Among them, the molar ratio of oxalic acid to the total molar amount of zirconium source and cerium source is 1:94.

[0066] (3) Transfer the mixed solution C to a hydrothermal reactor, carry out hydrothermal reaction at 130 °C for 10 h, filter to obtain a composite catalyst support, dry it at 100 °C for 15 h, and calcine the dried solid under the protection of nitrogen inert gas at 350 °C to obtain a composite support.

[0067] (4) Add 500 mL of purified water to a four-necked flask, add 30 g of the composite support at room temperature, stir evenly to obtain a first slurry. Then add 30.4 g (0.1277 mol) of nickel chloride hexahydrate (i.e., nickel source: composite support = 1.01:1, weight ratio) to it, and stir for 0.6 h to obtain a second slurry.

[0068] (5) Cool the second slurry to 0 °C by circulating water bath, and dropwise add a solution of 28.15 g (0.32 mol) of NaH2PO2 and a solution of 9.7 g (0.18 mol) of KBH4 dropwise under stirring. During this process, adjust the pH = 12 with 30% ammonia water. Among them, the molar ratio of boron source to phosphorus source is 1:1.8; the molar amount of nickel source to the total molar amount of boron source and phosphorus source is 1:3.92. After the dropping is completed, stop the reaction when no gas is released, filter, collect the black precipitate by suction filtration, wash the black precipitate repeatedly with deionized water until the pH = 7.2, then wash it twice with anhydrous ethanol, and dry the obtained product in a vacuum drying oven at 80 °C for 7 h to obtain a nitro-hydrogenation catalyst.

[0069] Example 4

[0070] A preparation method of a nitro-hydrogenation catalyst:

[0071] The difference between this example and Example 1 is only that: in step (2), the molar ratio of zirconium source to cerium source is changed to 1:0.1.

[0072] Example 5

[0073] A preparation method of a nitro-hydrogenation catalyst:

[0074] The difference between this example and Example 1 is only that: in step (2), the molar ratio of the zirconium source to the cerium source is changed to 1:1.

[0075] Example 6

[0076] A method for preparing a nitro-hydrogenation catalyst:

[0077] The difference between this example and Example 1 is only that: in step (2), the molar ratio of citric acid to the total molar amount of the zirconium source and the cerium source is changed to 1:70.

[0078] Example 7

[0079] A method for preparing a nitro-hydrogenation catalyst:

[0080] The difference between this example and Example 1 is only that: in step (2), the molar ratio of citric acid to the total molar amount of the zirconium source and the cerium source is changed to 1:100.

[0081] Example 8

[0082] A method for preparing a nitro-hydrogenation catalyst:

[0083] The difference between this example and Example 1 is only that: in step (2), when the precipitant solution and the mixture B are added dropwise to the mixture A in parallel flow, heating is not carried out, but the addition is directly carried out at room temperature (25±5°C).

[0084] Example 9

[0085] A method for preparing a nitro-hydrogenation catalyst:

[0086] The difference between this example and Example 1 is only that: in step (3), the reaction temperature of the hydrothermal reaction is changed to 110°C, and the holding time is changed to 15 h.

[0087] Example 10

[0088] A method for preparing a nitro-hydrogenation catalyst:

[0089] The difference between this example and Example 1 is only that: in step (3), the reaction temperature of the hydrothermal reaction is changed to 160°C, and the holding time is changed to 6 h.

[0090] Example 11

[0091] A method for preparing a nitro-hydrogenation catalyst:

[0092] The difference between this example and Example 1 is only that: in step (3), the calcination temperature of the calcination treatment is changed to 250°C.

[0093] Example 12

[0094] A preparation method of a nitro-hydrogenation catalyst:

[0095] The difference between this example and Example 1 is only that: in step (3), the calcination temperature of the calcination treatment is changed to 450 °C.

[0096] Example 13

[0097] A preparation method of a nitro-hydrogenation catalyst:

[0098] The difference between this example and Example 1 is only that: in step (4), the weight ratio of the nickel source to the composite support is changed to 0.5:1.

[0099] Example 14

[0100] A preparation method of a nitro-hydrogenation catalyst:

[0101] The difference between this example and Example 1 is only that: in step (4), the weight ratio of the nickel source to the composite support is changed to 1.2:1.

[0102] Example 15

[0103] A preparation method of a nitro-hydrogenation catalyst:

[0104] The difference between this example and Example 1 is only that: in step (5), the molar ratio of the boron source to the phosphorus source is changed to 1:1; the molar amount ratio of the nickel source to the total molar amount of the boron source and the phosphorus source is then changed to 1:2.5.

[0105] Example 16

[0106] A preparation method of a nitro-hydrogenation catalyst:

[0107] The difference between this example and Example 1 is only that: in step (5), the molar ratio of the boron source to the phosphorus source is changed to 1:1.2; the molar amount ratio of the nickel source to the total molar amount of the boron source and the phosphorus source is then changed to 1:4.5.

[0108] Comparative Example 1

[0109] A preparation method of a nitro-hydrogenation catalyst:

[0110] The difference between this comparative example and Example 1 is only that: steps (1), (4) and (5) are not carried out, but instead the cerium source is directly formulated into a solution and subjected to precipitation, hydrothermal reaction and calcination steps.

[0111] Comparative Example 2

[0112] A preparation method of a nitro-hydrogenation catalyst:

[0113] The difference between this comparative example and Example 1 is only that steps (2), (4), and (5) were not carried out, but instead, the mixed A obtained in step (1) was directly subjected to a hydrothermal reaction and a calcination step.

[0114] Comparative Example 3

[0115] A method for preparing a nitro-hydrogenation catalyst:

[0116] The difference between this comparative example and Example 1 is only that no boron source was added in step (4).

[0117] Comparative Example 4

[0118] A method for preparing a nitro-hydrogenation catalyst:

[0119] The difference between this comparative example and Example 1 is only that no phosphorus source was added in step (5).

[0120] Application Example 1

[0121] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0122] The nitro-hydrogenation catalyst obtained in Example 1 was used as the catalyst.

[0123] After putting 40 g of the catalyst into a fixed bed, it was activated for 3 h under a hydrogen atmosphere at a heating rate of 10 °C / min up to 100 °C.

[0124] After that, the temperature was lowered to the reaction temperature of 50 °C, and a 0.5 M methanol solution of 2-nitro-N,3-dimethylbenzamide was fed at a rate of 1 g / min, and hydrogen was fed at a rate of 20 mL / min, and a hydrogenation catalytic reaction was carried out. After the reaction, it was tested by liquid phase, and the results are shown in Table 1.

[0125] Application Example 2

[0126] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0127] The nitro-hydrogenation catalyst obtained in Example 1 was used as the catalyst.

[0128] After putting 40 g of the catalyst into a fixed bed, it was activated for 2 h under a hydrogen atmosphere at a heating rate of 10 °C / min up to 140 °C.

[0129] After that, the temperature was lowered to the reaction temperature of 60 °C, and a 0.5 M methanol solution of 2-nitro-N,3-dimethylbenzamide was fed at a rate of 1 g / min, and hydrogen was fed at a rate of 25 mL / min, and a hydrogenation catalytic reaction was carried out. After the reaction, it was tested by liquid phase, and the results are shown in Table 1.

[0130] Application Example 3

[0131] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0132] Use the nitro hydrogenation catalyst obtained in Example 1 as the catalyst used.

[0133] After putting 40 g of the catalyst into the fixed bed, heat it up to 150 °C at a heating rate of 10 °C / min under a hydrogen atmosphere and activate it for 3 h.

[0134] After that, cool it down to the reaction temperature of 55 °C, and feed a methanol solution of 0.5 M 2-nitro-N,3-dimethylbenzamide at a feeding rate of 1 g / min and feed hydrogen at a feeding rate of 30 mL / min, and carry out the hydrogenation catalytic reaction. After the reaction, perform liquid-phase testing, and the results are shown in Table 1. The liquid-phase test result diagram is shown in Figure 1 .

[0135] Application Example 4

[0136] Use the nitro hydrogenation catalyst obtained in Example 4 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid-phase testing on the reaction results, and the results are shown in Table 1.

[0137] Application Example 5

[0138] Use the nitro hydrogenation catalyst obtained in Example 5 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid-phase testing on the reaction results, and the results are shown in Table 1.

[0139] Application Example 6

[0140] Use the nitro hydrogenation catalyst obtained in Example 6 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid-phase testing on the reaction results, and the results are shown in Table 1.

[0141] Application Example 7

[0142] Use the nitro hydrogenation catalyst obtained in Example 7 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid-phase testing on the reaction results, and the results are shown in Table 1.

[0143] Application Example 8

[0144] Use the nitro hydrogenation catalyst obtained in Example 8 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid-phase testing on the reaction results, and the results are shown in Table 1.

[0145] Application Example 9

[0146] Use the nitro hydrogenation catalyst obtained in Example 9 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0147] Application Example 10

[0148] Use the nitro hydrogenation catalyst obtained in Example 10 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0149] Application Example 11

[0150] Use the nitro hydrogenation catalyst obtained in Example 11 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0151] Application Example 12

[0152] Use the nitro hydrogenation catalyst obtained in Example 12 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0153] Application Example 13

[0154] Use the nitro hydrogenation catalyst obtained in Example 13 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0155] Application Example 14

[0156] Use the nitro hydrogenation catalyst obtained in Example 14 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0157] Application Example 15

[0158] Use the nitro hydrogenation catalyst obtained in Example 15 as the catalyst used, activate it according to the conditions in Application Example 1, and achieve the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. The reaction results were tested by liquid phase, as shown in Table 1.

[0159] Application Example 16

[0160] Use the nitro-hydrogenation catalyst obtained in Example 16 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Test the reaction results by liquid phase, as shown in Table 1.

[0161] Application Example 17

[0162] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0163] Use the nitro-hydrogenation catalyst obtained in Example 1 as the catalyst used.

[0164] After putting 40 g of the catalyst into the fixed bed, activate it for 4 h under the condition of heating up at a rate of 5 °C / min to 80 °C in a hydrogen atmosphere.

[0165] After that, carry out the hydrogenation catalytic reaction according to the conditions in Application Example 1. Test by liquid phase after the reaction, and the results are shown in Table 1.

[0166] Application Example 18

[0167] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0168] Use the nitro-hydrogenation catalyst obtained in Example 1 as the catalyst used.

[0169] After putting 40 g of the catalyst into the fixed bed, activate it for 1 h under the condition of heating up at a rate of 15 °C / min to 160 °C in a hydrogen atmosphere.

[0170] After that, carry out the hydrogenation catalytic reaction according to the conditions in Application Example 1. Test by liquid phase after the reaction, and the results are shown in Table 1.

[0171] Application Example 19

[0172] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0173] Use the nitro-hydrogenation catalyst obtained in Example 1 as the catalyst used, and carry out the activation treatment according to the conditions in Application Example 1.

[0174] After that, cool down to the reaction temperature of 45 °C, and feed a methanol solution of 0.5 M 2-nitro-N,3-dimethylbenzamide at a feed rate of 0.5 g / min and hydrogen at a feed rate of 10 mL / min, and carry out the hydrogenation catalytic reaction. Test by liquid phase after the reaction, and the results are shown in Table 1.

[0175] Application Example 20

[0176] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0177] Use the nitro hydrogenation catalyst obtained in Example 1 as the catalyst used, and perform activation treatment according to the conditions in Application Example 1.

[0178] After that, cool down to the reaction temperature of 65 °C, and feed a methanol solution of 0.5 M 2-nitro-N,3-dimethylbenzamide at a feed rate of 1.5 g / min and hydrogen at a feed rate of 40 mL / min, and carry out the hydrogenation catalytic reaction. After the reaction, perform liquid phase testing, and the results are shown in Table 1.

[0179] Application Example 21

[0180] Hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide:

[0181] Use the nitro hydrogenation catalyst obtained in Example 1 as the catalyst used, activate it according to the conditions in Application Example 1, set the test time to 2600 h, and under long-term use conditions, realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide according to the conditions in Application Example 1. Perform liquid phase testing on the reaction results, and the results are shown in Table 1.

[0182] Application Comparative Example 1

[0183] Use the nitro hydrogenation catalyst obtained in Comparative Example 1 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid phase testing on the reaction results, and the results are shown in Table 1.

[0184] Application Comparative Example 2

[0185] Use the nitro hydrogenation catalyst obtained in Comparative Example 2 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid phase testing on the reaction results, and the results are shown in Table 1.

[0186] Application Comparative Example 3

[0187] Use the nitro hydrogenation catalyst obtained in Comparative Example 3 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid phase testing on the reaction results, and the results are shown in Table 1.

[0188] Application Comparative Example 4

[0189] Use the nitro hydrogenation catalyst obtained in Comparative Example 4 as the catalyst used, activate it according to the conditions in Application Example 1, and realize the hydrogenation reaction of 2-nitro-N,3-dimethylbenzamide. Perform liquid phase testing on the reaction results, and the results are shown in Table 1.

[0190] Table 1

[0191]

[0192]

[0193] From the above description, it can be seen that compared with each comparative example, the above-mentioned embodiments of the present invention achieve the preparation of a nitro-hydrogenation catalyst with superior performance. The obtained catalyst with nano-amorphous Ni-B / P components can continuously catalyze the hydrogenation of nitro-aromatic compounds in a fixed bed under mild conditions, improve its production conditions, and has a high conversion rate and aniline product selectivity.

[0194] Specifically, in each embodiment, by comparing Example 4, 5 with Examples 1 to 3, it can be known that by optimizing the molar ratio of the zirconium source to the cerium source, it is more conducive to the preferential deposition of cerium ions on the surface of ZrO2 particles, forming a more stable transition layer with gradually increasing cerium content, thereby more significantly enhancing the adsorption capacity of the catalyst for nitro compounds.

[0195] By comparing Example 6, 7 with Examples 1 to 3, it can be known that an acid agent with a more appropriate dosage can promote the formation of a material with a highly stable and uniform structure during the hydrothermal treatment of the composite carrier precursor, and finally optimize the activity of the obtained catalyst.

[0196] By comparing Example 8 with Examples 1 to 3, it can be known that by mixing the solution containing the zirconium source and the cerium source within a suitable temperature range and simultaneously carrying out the precipitation reaction, the porosity and surface area of the obtained carrier can be further optimized, providing more active sites for the subsequent deposition of the amorphous alloy.

[0197] By comparing Example 9, 10 with Examples 1 to 3, it can be known that by optimizing the temperature and time of the hydrothermal reaction, the uniform growth of zirconium-cerium oxide grains can be promoted, thereby further enhancing the binding strength between the amorphous alloy and the carrier, and finally making it exhibit higher catalytic activity.

[0198] By comparing Example 11, 12 with Examples 1 to 3, it can be known that by optimizing the calcination temperature and conditions of the calcination treatment, the thermal stability of the obtained composite carrier can be further improved, promoting the formation of oxygen vacancies on the surface of the carrier, and enhancing the activity and stability of the obtained catalyst.

[0199] By comparing Example 13, 14 with Examples 1 to 3, it can be known that by optimizing the weight ratio of the nickel source to the composite carrier, the strong interaction between the metal active component nickel and the carrier can be more significantly promoted, and finally the efficiency of the catalytic hydrogenolysis reaction can be improved, especially for the cleavage of the N-O bond, thereby realizing the more efficient progress of the nitro-hydrogenation reaction.

[0200] Comparing Example 15 and 16 with Examples 1 to 3, it can be seen that by optimizing the molar ratios of boron, phosphorus, and nickel, the resulting catalyst can have a more stable electronic state and spatial configuration, enabling efficient cleavage of the N-O bond in the nitro-hydrogenation reaction, while reducing the occurrence of over-hydrogenation side reactions and improving the production purity and selectivity of aniline derivatives.

[0201] During the application of the nitro-hydrogenation catalysts obtained in each example as hydrogenation reaction catalysts, comparing Application Example 17 and 18 with Application Example 1, it can be seen that by optimizing the activation treatment conditions of the nitro-hydrogenation catalyst, the oxygen vacancies on the surface of the nitro-hydrogenation catalyst can be pre-reacted with hydrogen more effectively to form more active hydrogen species, which can then participate more effectively in the subsequent hydrogenation reaction and promote the conversion of nitro compounds. Comparing Application Example 19 and 20 with Application Example 1, it can be seen that for the catalysts obtained in the embodiments of the present invention, by optimizing their application conditions, the activity and stability of the catalyst can be more fully exerted, thereby achieving a more efficient and highly selective hydrogenation reaction of nitroarenes.

[0202] It should be noted that the terms "first", "second", etc. in the specification and claims of this application are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances so that the embodiments of the present application described herein can be implemented in an order other than those described herein.

[0203] The above are only the preferred embodiments of the present invention and are not used to limit the present invention. For those skilled in the art, the present invention can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a nitro-hydrogenation catalyst, characterized in that, Including: Step S1: Prepare a zirconium source solution by mixing a zirconium source, a first acid agent and water, and add a first precipitant to the zirconium source solution to obtain a mixed solution A with a pH of 8.5 - 9.0; Step S2: Prepare a mixed solution B by mixing a cerium source, a second acid agent and water, and add the mixed solution B and a second precipitant to the mixed solution A to obtain a mixed solution C with a pH of 6.8 - 7.2; Step S3: Subject the mixed solution C to a hydrothermal reaction to obtain a support precursor; The support precursor is calcined to obtain a composite support; Step S4: Prepare a first slurry by mixing the composite support and water, and add a nickel source to the first slurry. After mixing, a second slurry is obtained; Step S5: Under the condition of 0 ± 5°C, add a boron source and a phosphorus source to the second slurry and stir to react, so that the boron source, the phosphorus source and the nickel source are deposited on the composite support to form an amorphous alloy, thereby obtaining the nitro-hydrogenation catalyst.

2. The method for preparing a nitro-hydrogenation catalyst according to claim 1, wherein the molar ratio of the zirconium source to the cerium source is 1:(0.2 - 0.5); and / or, the zirconium source is selected from one or more of zirconium nitrate, zirconyl chloride, zirconium acetate, zirconium sulfate, zirconium carbonate and zirconium chloride; and / or, the cerium source is selected from one or more of cerium nitrate, cerium chloride and cerium acetate.

3. The method for preparing a nitro-hydrogenation catalyst according to claim 1, wherein denote the total molar amount of the zirconium source and the cerium source as M1, and denote the total molar amount of the first acid agent and the second acid agent as M2, M2:M1 = 1:(75 - 95); and / or, the first acid agent and the second acid agent are each independently selected from one or more of citric acid, oxalic acid, acetic acid and nitric acid, and the first acid agent and the second acid agent are both added in the form of an acid solution with a molar concentration of 0.08M - 0.1M; and / or, the first precipitant and the second precipitant are each independently selected from one or more of sodium hydroxide, sodium carbonate and ammonia water.

4. The preparation method of the nitro hydrogenation catalyst according to any one of claims 1 to 3, characterized in that, In the step S3, the reaction temperature of the hydrothermal reaction is 120°C - 150°C, and the time is 8h - 12h; and / or, the calcination temperature of the calcination treatment is 300°C - 400°C, and the calcination treatment is carried out in an inert atmosphere.

5. The preparation method of the nitro hydrogenation catalyst according to any one of claims 1 to 3, characterized in that, In the step S4, the weight ratio of the nickel source to the composite support is (0.6 - 1.12):1; and / or, the mixing is stirring mixing, and the stirring mixing time is 0.5h - 1h; and / or, the nickel source is selected from one or more of nickel nitrate, nickel sulfate hexahydrate and nickel chloride.

6. The preparation method of the nitro hydrogenation catalyst according to any one of claims 1 to 3, characterized in that, In the step S5, the molar ratio of the boron source to the phosphorus source is 1:(1.5 - 2); and / or, the molar amount ratio of the nickel source to the total molar amount of the boron source and the phosphorus source is 1:(2.8 - 4.0); the boron source is selected from one or more of KBH4, NaBH4 and (CH3COO)3BHNa; and / or, the phosphorus source is selected from one or more of NaH2PO2, H3PO2 and H6NO3P; and / or, The boron source and the phosphorus source are added by dropping, and during the dropping process, step S5 further includes adding an alkali solution to the second slurry to keep the pH of the second slurry at 12 ± 0.2; The alkali solution is selected from one or more of sodium hydroxide solution, sodium carbonate solution, and ammonia water.

7. A nitro-hydrogenation catalyst, characterized in that, The nitro-hydrogenation catalyst is prepared by the preparation method of the nitro-hydrogenation catalyst according to any one of claims 1 to 6.

8. A method for preparing an aniline compound by catalytic hydrogenation, characterized in that, The nitroaromatic compound and hydrogen are subjected to a hydrogenation reaction under the action of the nitro-hydrogenation catalyst according to claim 7 to obtain the aniline compound.

9. The method for preparing an aniline compound by catalytic hydrogenation according to claim 8, wherein Before the hydrogenation reaction, the catalytic hydrogenation preparation method of the aniline compound further includes loading the nitro-hydrogenation catalyst into a fixed bed and performing an activation treatment, and the activation treatment includes: Under a hydrogen atmosphere, heating to 100°C to 150°C at a heating rate of 10 ± 2°C / min and holding for 2 h to 3 h.

10. The method for preparing an aniline compound by catalytic hydrogenation according to claim 8 or 9, characterized in that, During the hydrogenation reaction, The feeding rate of the nitroaromatic compound is 1.0 ± 0.2 g / min; The feeding rate of the hydrogen is 20 mL / min to 30 mL / min; The reaction temperature is 50°C to 60°C.

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