A method for continuous preparation of supported nickel-based catalysts and use thereof

Abstract

This invention discloses a continuous preparation method for supported nickel-based catalysts and their applications. This method utilizes the precise microporous structure of a membrane-dispersed microreactor to achieve efficient and uniform mixing of the active component (Ni metal) and the promoter (Ce) with the support precursor. By precisely controlling key parameters such as pH and flow rate, the nucleation and growth processes are controlled, enabling the continuous preparation of nanoscale bimetallic catalysts. This shortens the preparation time and makes the process more environmentally friendly and efficient. The catalyst prepared by this invention fully leverages the synergistic catalytic effect between the nickel and cerium components. Under mild reaction conditions, it exhibits excellent catalytic activity and stability in the debenzylation reaction of N-benzylaniline, achieving a conversion rate of up to 95% and a selectivity greater than 99%, demonstrating promising prospects for industrial application.

Description

Technical Field

[0001] This invention belongs to the field of catalytic material preparation and fine chemical technology, specifically relating to a method for the continuous preparation of supported nano-nickel-based catalysts using a membrane dispersion microreactor, and the application of the catalyst in the catalytic hydrogenolysis reaction to remove N-benzyl protecting groups. Background Technology

[0002] In pharmaceutical synthesis and fine chemical engineering, benzyl, as one of the most classic and widely used amino and hydroxyl protecting groups, possesses excellent chemical stability and is easy to introduce, playing a crucial role in the targeted synthesis of complex target molecules. However, the targeted and efficient removal of protecting groups is a key step in multi-step organic synthesis routes. Traditional debenzylation processes often involve the use of strong acids, strong bases, or strong oxidants, which not only leads to difficult separation and purification and lengthy steps but also damages other sensitive functional groups in the molecule, accompanied by environmental pollution problems. In contrast, catalytic hydrogenolysis of benzyl is recognized as the most economical and environmentally friendly deprotection technology due to its mild reaction conditions, few byproducts, high atom economy, and compliance with the principles of green chemistry. However, with the increasing demands for production efficiency and cost control in the pharmaceutical industry, developing high-performance catalytic systems that can achieve high yields, high selectivity, and are suitable for large-scale continuous production has become a highly challenging and valuable research topic in this field.

[0003] Currently, industry mainly relies on palladium-based noble metal catalysts. These catalysts possess excellent hydrogen activation capabilities, but their scarcity leads to high acquisition costs, and their extremely strong intrinsic hydrogenation activity easily induces side reactions such as over-hydrogenation or dehalogenation. For example, Hwang et al. (Chemical Engineering Journal, 2016, 288: 758-769.) found that although Pd / C exhibits excellent hydrogenolysis activity for N-benzyl-4-fluoroaniline under mild conditions (40 °C, 5 atm H2), it readily induces CF bond cleavage during the reaction, generating the defluorination byproduct aniline, making precise control of chemoselectivity difficult. To address these issues, researchers are committed to developing low-cost, non-noble metal nickel-based alternatives. Beller's team (ACSSustainable Chemistry & Engineering, 2019, 7(20): 17107-17113.) prepared a Ni-NC@Al2O3 catalyst via pyrolysis. Although this protected the active core, it still required a high temperature of 140 °C when dealing with N-benzylaniline, resulting in a low aniline yield. Liu Shuang's team (Catalysis Letters, 2023, 153(10): 3031-3043.) prepared a Ni / Al2O3 catalyst via co-precipitation. Although this enhanced the anti-sintering ability, it also relied on harsh conditions of 150 °C and 30 bar H2, and the preparation process was complex, with problems such as high equipment requirements and long preparation time.

[0004] In summary, developing a non-precious metal nickel-based catalytic system with simple preparation process, mild reaction conditions, and high hydrogenation activity is of great application value and engineering significance for reducing production costs, promoting the large-scale application of green catalytic technology, and sustainable development. Summary of the Invention

[0005] The purpose of this invention is to address the limitations of current technologies by providing a continuous preparation method for supported nickel-based catalysts and their application in the hydrodebenzylation of N-benzylaniline. This method utilizes the precise microporous structure of a membrane-dispersed microreactor to achieve efficient and uniform mixing of the active component (Ni) and the auxiliary agent (Ce) with the supported precursor. By precisely controlling key parameters such as pH and flow rate, the nucleation and growth processes are precisely regulated, enabling the continuous preparation of nanoscale bimetallic catalysts, shortening the preparation time, and making the process more environmentally friendly and efficient. The catalyst prepared by this invention fully leverages the synergistic catalytic effect between the nickel and cerium components. Under mild reaction conditions, it exhibits excellent catalytic activity and stability in the hydrodebenzylation of N-benzylaniline, achieving a conversion rate of up to 95% and a selectivity greater than 99%, demonstrating promising prospects for industrial application.

[0006] The technical solution of this invention is as follows: A continuous preparation method for a supported nickel-based catalyst, comprising the following steps: Na₂SiO₃ solution and sulfuric acid were separately fed into feed pumps and then mixed in the first membrane dispersion microreactor A at 50–70 °C. The pH of the effluent was adjusted to 5.5–8.5. After residence in the pipeline for 10–20 min, a silica gel was formed. The resulting gel was introduced through the left port of a tee, and a metal salt solution was fed into the feed pump and then introduced through the right port of the tee. The two solutions were mixed and then introduced into the continuous phase end of the second membrane dispersion microreactor B. At the same time, Na₂CO₃ solution was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump and mixed. After residence in the pipeline for 1–5 min, a catalyst suspension was obtained. The collected suspension was centrifuged, washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. Finally, it was calcined in air at 300–500 °C for 3–5 hours and reduced in a hydrogen atmosphere at 300–500 °C for 3–5 hours to obtain the target catalyst Ni-Ce / SiO₂. Among them, Na2SiO3 solution, metal salt solution and Na2CO3 solution are introduced into the membrane dispersion microreactor at a flow rate ratio of 1:1:1; The flow rate of sulfuric acid is adjusted to control the pH value of the system; The flow rate of the Na2SiO3 solution was 2.5~7.5 mL / min; In the membrane dispersion microreactor, the stainless steel microfiltration membrane has a pore size of 0.5~5μm and a diameter of 6.5~100 mm; the residence tube is made of polytetrafluoroethylene, with an inner diameter of 1.5~2.5 mm and a length of 2.5~60 m. The concentration of the Na2SiO3 solution is 0.03~0.15 mol / L; the concentration of the sulfuric acid is 0.03~0.15 mol / L. In the metal salt solution, the metal salts are Ni(NO3)2 and Ce(NO3)3, with a molar ratio of Ni:Ce = 19~3:1; the total metal salt concentration is 0.05~0.25 mol / L; the molar ratio of the total metal in the metal salt solution to SiO2 in the Na2SiO3 solution is 1:0.3~1.5. The concentration of the Na2CO3 solution is 0.05~0.25 mol / L.

[0007] Among them, Na2SiO3·9H2O is preferably 0.09 mol / L, H2SO4 is preferably 0.09 mol / L, Ni(NO3)2·6H2O is preferably 0.1275 mol / L, Ce(NO3)3·6H2O is preferably 0.0225 mol / L, and Na2CO3 is preferably 0.30 mol / L; The supported catalyst comprises an active component and a support, wherein the support is silica, and the active component is a main metal M1 or a main metal M1 and a co-metal M2; the molar ratio of the active component to the support is 1:0.3~1.5; the molar ratio of the main metal M1 to the co-metal M2 is 19~3:1. The main metal M1 of the catalyst is Ni; The catalyst's promoter M2 is Ce; The application of the catalyst prepared by the method in the hydrogenolysis of N-benzylaniline includes the following steps: N-Benzylaniline, isopropanol-water mixed solvent, and supported catalyst were added to a batch high-pressure reactor; the reactor was sealed, and high-purity N2 was introduced to replace the air in the reactor 3 to 7 times, followed by high-purity H2 to replace it 3 to 7 times; H2 at 0.05 to 0.20 MPa was introduced, and the reaction was carried out at 70 to 100 °C for 4 to 9 h to debenzylate.

[0008] The mass ratio of N-benzylaniline to catalyst is 100~20:1; 3 mL of isopropanol-water mixed solvent, wherein the volume ratio of alcohol to water is 1:1; 0.5~2.0 mmol of N-benzylaniline is added to every 3 mL of mixed solvent.

[0009] The essential features of this invention are: This invention proposes a continuous preparation method for non-noble metal nano-nickel-based catalysts based on a membrane dispersion microreactor. This process not only utilizes the unique microfluidic characteristics of the membrane dispersion microreactor, but also achieves efficient and uniform mixing of materials in a microscale space through the cross-flow shearing effect of the microporous membrane on the dispersed phase, effectively shortening the catalyst preparation time and simplifying subsequent processing steps. Simultaneously, through synergistic optimization of key process parameters such as pH and flow rate, the condensation process of the support precursor is effectively controlled, providing a controllable environment for the nucleation and growth of nanoparticles. This constructs a stable mesoporous framework with excellent physical confinement effects, facilitating the high dispersion of metal components on the silica support surface and inhibiting the nucleation, growth, and aggregation of active components.

[0010] Furthermore, the supported catalyst constructed in this invention achieves synergistic catalytic effects between bimetallic components through the rational combination of nickel and cerium components. The introduction of the cerium component improves the electronic environment of the nickel active species and induces the generation of interfacial oxygen vacancies, thereby enhancing the catalyst's adsorption and activation capabilities for substrate molecules. This preparation method has good process economy, and the prepared catalyst exhibits good reactivity and stability under mild hydrogenobenzyl dehydrogenation reaction conditions, providing a reliable technical solution for the continuous and green production of non-precious metal catalysts.

[0011] The beneficial effects of this invention are as follows: This invention provides a non-precious metal nickel-based catalytic system for the hydrogenolysis of N-benzylaniline, achieving highly efficient conversion under mild reaction conditions (preferably a reaction temperature of 90 °C and a hydrogen pressure of 0.1 MPa). This method exhibits extremely high chemoselectivity, with an N-benzylaniline conversion rate of up to 94.89% and a product aniline conversion rate of up to 94.62%. The reaction system generates virtually no byproducts, reducing the requirements for explosion-proof equipment and high-pressure operation, significantly improving the economic feasibility of production, and simplifying post-processing.

[0012] This invention relates to the preparation of supported nickel-based catalysts via membrane dispersion microreactors, using non-precious metals as the active component. This method enables the continuous preparation of supported catalysts, and the preparation process is green, simple, and has good potential for industrial scale-up. The active metal component in this catalyst is highly uniformly dispersed on the support surface, exhibiting good catalytic performance and stability in the catalytic debenzylation reaction of N-benzylaniline, and shows promising application prospects. Attached Figure Description

[0013] Figure 1 XRD patterns of the catalysts prepared in Examples 1 and 11 Figure 2 TEM image of the catalyst prepared in Example 11 Figure 3 The N2- adsorption-desorption isotherms of the catalysts prepared in Examples 11, 20, and 21 Figure 4 Pore ​​size distribution diagrams of the catalysts prepared in Examples 11, 20, and 21. Detailed Implementation

[0014] The present invention will be further described in detail below with reference to specific embodiments, but the scope of protection of the present invention is not limited to the content described.

[0015] The membrane dispersion microreactor A and membrane dispersion microreactor B involved in this invention have identical structures (excluding the residence tube). Specifically, they are stainless steel microfiltration membranes with a pore size of 1 μm, a diameter of 1.6 mm, and a thickness of 6 mm. Both microreactors are connected to a residence tube made of polytetrafluoroethylene (PTFE) with an inner diameter of 2 mm. The tube length can be adjusted according to the required residence time (for example, when the residence time is 15 min, the tube length is set to 15 m). It should be noted that the residence tube and the membrane dispersion microreactor are independent components; if the residence time differs in different embodiments, only the length of the residence tube needs to be changed, and the two membrane dispersion microreactors themselves remain identical.

[0016] Example 1: Preparation of 20-Ni / 0.6SiO2-8.5-400-500 0.096 mol Na₂SiO₃·9H₂O was dissolved in 800 mL of deionized water to form solution A; 0.096 mol concentrated H₂SO₄ was diluted in 800 mL of deionized water to form solution B; 0.16 mol Ni(NO₃)₂·6H₂O was dissolved in 800 mL of deionized water to form solution C; and 0.32 mol Na₂CO₃ was dissolved in 800 mL of deionized water to form solution D. Solution A was introduced into the first membrane dispersion microreactor A at a flow rate of 5 mL / min, while the feed flow rate of solution B was adjusted to maintain the pH of the mixture at 8.5; the resulting mixture was then held in a residence tube for 15 min to form a silica gel. The obtained gel was introduced through the left port of a tee, and solution C was introduced through the right port of the tee at a flow rate of 5 mL / min. After mixing, the mixture was introduced into the continuous phase end of the second membrane dispersion microreactor B. Simultaneously, solution D was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump at a flow rate of 5 mL / min for mixing. The resulting suspension was collected through a residence pipe. The collected suspension was centrifuged and washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. The precursor was calcined in a muffle furnace at 400 °C for 4 h, and then reduced in a tube furnace at 500 °C under H2 atmosphere for 3 h to obtain the catalyst 20-Ni / 0.6SiO2-8.5-400-500.

[0017] Examples 2-5: Preparation of 20-Ni / 0.3SiO2-8.5-400-500, 20-Ni / 0.9SiO2-8.5-400-500, 20-Ni / 1.2SiO2-8.5-400-500, and 20-Ni / 1.5SiO2-8.5-400-500 The other steps are the same as in Example 1, except that the amount of Na2SiO3·9H2O is changed to 0.048 mol, 0.144 mol, 0.192 mol, and 0.24 mol, respectively. Finally, four materials with different Ni / Si molar ratios were obtained: 20-Ni / 0.3SiO2-400-500, 20-Ni / 0.9SiO2-400-500, 20-Ni / 1.2SiO2-400-500, and 20-Ni / 1.5SiO2-400-500 catalysts.

[0018] The catalyst is represented by L-xM1-yM2 / zSiO2-Pab, where L represents the sum of the total flow rates of the four solutions (solutions A / B / C / D), M1 represents the main metal, M2 represents the auxiliary metal, x and y represent the proportions of M1 and M2 in the total molar amount of the catalyst, z represents the molar ratio of the total metal to silicon dioxide, P represents the pH value of the mixture flowing out of the membrane dispersion microreactor A, a represents the calcination temperature of the catalyst, and b represents the reduction temperature of the catalyst.

[0019] Example 6: Preparation of 20-9Ni-1Ce / 0.6SiO2-8.5-400-500 0.072 mol Na₂SiO₃·9H₂O was dissolved in 800 mL of deionized water to form solution A; 0.072 mol concentrated H₂SO₄ was diluted in 800 mL of deionized water to form solution B; 0.108 mol Ni(NO₃)₂·6H₂O and 0.012 mol Ce(NO₃)₃·6H₂O were dissolved in 800 mL of deionized water to form solution C; 0.24 mol Na₂CO₃ was dissolved in 800 mL of deionized water to form solution D. Solution A was introduced into the first membrane dispersion microreactor A at a flow rate of 5 mL / min, while the feed flow rate of solution B was adjusted to maintain the pH of the mixture at 8.5; the resulting mixture was then held in a residence tube for 15 min to form a silica gel. The obtained gel was introduced through the left port of a tee, and solution C was introduced through the right port of the tee at a flow rate of 5 mL / min. After mixing, the mixture was introduced into the continuous phase end of the second membrane dispersion microreactor B. Simultaneously, solution D was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump at a flow rate of 5 mL / min for mixing. The resulting suspension was collected after a 2-min residence time. The collected suspension was centrifuged and washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. The precursor was calcined in a muffle furnace at 400 °C for 4 h, and then reduced in a tube furnace at 500 °C under H2 atmosphere for 3 h to obtain the catalyst 20-9Ni-1Ce / 0.6SiO2-8.5-400-500.

[0020] Examples 7-10: Preparation of 20-9Ni-1Zr / 0.6SiO2-8.5-400-500, 20-9Ni-1La / 0.6SiO2-8.5-400-500, 20-9Ni-1Co / 0.6SiO2-8.5-400-500, and 20-9Ni-1Fe / 0.6SiO2-8.5-400-500 The other steps are the same as in Example 6, except that 0.012 mol Ce(NO3)3·6H2O is replaced with 0.012 mol Zr(NO3)4·5H2O, 0.012 mol La(NO3)3·6H2O, 0.012 mol Co(NO3)2·6H2O, and 0.012 mol Fe(NO3)3·9H2O, respectively. Four different materials were finally obtained: 20-9Ni-1Zr / 0.6SiO2-8.5-400-500, 20-9Ni-1La / 0.6SiO2-8.5-400-500, 20-9Ni-1Co / 0.6SiO2-8.5-400-500, and 20-9Ni-1Fe / 0.6SiO2-8.5-400-500.

[0021] Examples 11-14: Preparation of 20-7.5Ni-2.5Ce / 0.6SiO2-8.5-400-500, 20-8Ni-2Ce / 0.6SiO2-8.5-400-500, 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500, and 20-9.5Ni-0.5Ce / 0.6SiO2-8.5-400-500 The other steps are the same as in Example 6, except that the molar ratios of Ni(NO3)2·6H2O and Ce(NO3)3·6H2O are 0.75:0.25, 0.80:0.20, 0.85:0.15, and 0.95:0.05, respectively, with the total molar amounts of nickel and cerium being consistent. Four different materials were ultimately obtained: 20-7.5Ni-2.5Ce / 0.6SiO2-8.5-400-500, 20-8Ni-2Ce / 0.6SiO2-8.5-400-500, 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500, and 20-9.5Ni-0.5Ce / 0.6SiO2-8.5-400-500.

[0022] Depend on Figure 1 XRD patterns of the catalysts obtained in Examples 1 and 11 show that the intensity of the characteristic diffraction peak of Ni at 2θ 44.4° is significantly reduced and the full width at half maximum (FWHM) is significantly increased after the introduction of the rare earth element Ce into the catalyst, indicating that the incorporation of Ce effectively inhibits the growth process of Ni grains. TEM characterization analysis of the catalyst in Example 11 (…) Figure 2 As can be seen, the Ni and Ce components are highly uniformly dispersed on the surface of the SiO2 support, and the average particle size of the Ni nanoparticles is only 4.27 nm.

[0023] Example 15: Preparation of 20-8.5Ni-1.5Ce / 0.6SiO2-9.5-400-500 0.072 mol Na₂SiO₃·9H₂O was dissolved in 800 mL of deionized water to form solution A; 0.072 mol concentrated H₂SO₄ was diluted in 800 mL of deionized water to form solution B; 0.102 mol Ni(NO₃)₂·6H₂O and 0.018 mol Ce(NO₃)₃·6H₂O were dissolved in 800 mL of deionized water to form solution C; 0.24 mol Na₂CO₃ was dissolved in 800 mL of deionized water to form solution D. Solution A was introduced into the first membrane dispersion microreactor A at a flow rate of 5 mL / min, while the feed flow rate of solution B was adjusted to maintain the pH of the mixture at 9.5; the resulting mixture was then held in a residence tube for 15 min to form a silica gel. The obtained gel was introduced through the left port of a tee, and solution C was introduced through the right port of the tee at a flow rate of 5 mL / min. After mixing, the mixture was introduced into the continuous phase end of the second membrane dispersion microreactor B. Simultaneously, solution D was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump at a flow rate of 5 mL / min for mixing. The resulting suspension was collected through a residence pipe. The collected suspension was centrifuged and washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. The precursor was calcined in a muffle furnace at 400 °C for 4 h. Then, it was reduced in a tube furnace at 500 °C under H2 atmosphere for 3 h to obtain the catalyst 20-8.5Ni-1.5Ce / 0.6SiO2-9.5-400-500.

[0024] Examples 16-18: Preparation of 20-8.5Ni-1.5Ce / 0.6SiO2-5.5-400-500, 20-8.5Ni-1.5Ce / 0.6SiO2-6.5-400-500, and 20-8.5Ni-1.5Ce / 0.6SiO2-7.5-400-500 The other steps are the same as in Example 15, except that the pH of the mixture flowing out of the first membrane dispersion microreactor A is adjusted to 5.5, 6.5, and 7.5, respectively. Ultimately, three different materials are obtained: 20-8.5Ni-1.5Ce / 0.6SiO2-5.5-400-500, 20-8.5Ni-1.5Ce / 0.6SiO2-6.5-400-500, and 20-8.5Ni-1.5Ce / 0.6SiO2-7.5-400-500.

[0025] Example 19: Preparation of 10-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500 0.072 mol Na₂SiO₃·9H₂O was dissolved in 800 mL of deionized water to form solution A; 0.072 mol concentrated H₂SO₄ was diluted in 800 mL of deionized water to form solution B; 0.102 mol Ni(NO₃)₂·6H₂O and 0.018 mol Ce(NO₃)₃·6H₂O were dissolved in 800 mL of deionized water to form solution C; 0.24 mol Na₂CO₃ was dissolved in 800 mL of deionized water to form solution D. Solution A was introduced into the first membrane dispersion microreactor A at a flow rate of 2.5 mL / min, while the feed flow rate of solution B was adjusted to maintain the pH of the mixture at 8.5; the resulting mixture was then held in a residence tube for 15 min to form a silica gel. The obtained gel was introduced through the left port of a tee, and solution C was introduced through the right port of the tee at a flow rate of 2.5 mL / min. After mixing, the mixture was introduced into the continuous phase end of the second membrane dispersion microreactor B. Simultaneously, solution D was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump at a flow rate of 2.5 mL / min for mixing. The resulting suspension was collected through a residence pipe. The collected suspension was centrifuged and washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. The precursor was calcined in a muffle furnace at 400 °C for 4 h, and then reduced in a tube furnace at 500 °C under H2 atmosphere for 3 h to obtain the catalyst 10-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500.

[0026] Examples 20-22: Preparation of 15-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500, 25-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500, and 30-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500 The other steps are the same as in Example 20, except that the solution flow rate is adjusted to 3.75 mL / min, 6.25 mL / min, and 7.5 mL / min respectively (while changing the tube length to keep the residence time of the suspension in the tube constant). Finally, three different materials were obtained: 15-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500, 25-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500, and 30-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500.

[0027] Depend on Figure 3 Analysis of the N2- adsorption-desorption isotherms of the catalysts obtained in Examples 11, 20, and 21 shows that the curves conform to the typical characteristics of type IV isothermal adsorption curves, indicating that the catalysts have a mesoporous structure. Figure 4 In Example 11, the 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500 catalyst sample exhibited the narrowest and strongest pore size distribution peak, with pore sizes concentrated between 3-5 nm. This indicates that the silica framework formed at this flow rate is not only stable but also has highly regular pore spaces. When Ni and Ce precursors are subsequently introduced, the active components can be uniformly dispersed on the well-developed mesoporous channels and inner pore walls.

[0028] Table 1. Specific surface area and average pore size of catalyst L-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-500

[0029] Depend on Figure 4 The catalyst pore size distribution diagram and the data in Table 1 show that, within the total flow rate range of 15-25 mL / min, the specific surface area of ​​the catalyst first increases and then decreases as the flow rate increases, while the average pore size gradually increases. The maximum specific surface area of ​​397.37 m² is reached when the total flow rate is 20 mL / min. 2 / g, with a moderate average pore size of 4.64 nm.

[0030] Example 23: Preparation of 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-300-500 0.072 mol Na₂SiO₃·9H₂O was dissolved in 800 mL of deionized water to form solution A; 0.072 mol concentrated H₂SO₄ was diluted in 800 mL of deionized water to form solution B; 0.102 mol Ni(NO₃)₂·6H₂O and 0.018 mol Ce(NO₃)₃·6H₂O were dissolved in 800 mL of deionized water to form solution C; 0.24 mol Na₂CO₃ was dissolved in 800 mL of deionized water to form solution D. Solution A was introduced into the first membrane dispersion microreactor A at a flow rate of 5 mL / min, while the feed flow rate of solution B was adjusted to maintain the pH of the mixture at 8.5; the resulting mixture was then held in a residence tube for 15 min to form a silica gel. The obtained gel was introduced through the left port of a tee, and solution C was introduced through the right port of the tee at a flow rate of 5 mL / min. After mixing, the mixture was introduced into the continuous phase end of the second membrane dispersion microreactor B. Simultaneously, solution D was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump at a flow rate of 5 mL / min for mixing. The resulting suspension was collected through a residence pipe. The collected suspension was centrifuged and washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. The precursor was calcined in a muffle furnace at 300 °C for 4 h. Then, it was reduced in a tube furnace at 500 °C under H2 atmosphere for 3 h to obtain the catalyst 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-300 -500.

[0031] Examples 24-26: Preparation of 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-350-500, 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-450-500, and 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-500-500 The other steps are the same as in Example 23, except that the calcination temperatures in the muffle furnace are 350 ℃, 450 ℃, and 500 ℃, respectively. Ultimately, three different materials were obtained: 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-350-500, 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-450-500, and 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-500-500.

[0032] Example 27: Preparation of 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-400 0.072 mol Na₂SiO₃·9H₂O was dissolved in 800 mL of deionized water to form solution A; 0.072 mol concentrated H₂SO₄ was diluted in 800 mL of deionized water to form solution B; 0.102 mol Ni(NO₃)₂·6H₂O and 0.018 mol Ce(NO₃)₃·6H₂O were dissolved in 800 mL of deionized water to form solution C; 0.24 mol Na₂CO₃ was dissolved in 800 mL of deionized water to form solution D. Solution A was introduced into the first membrane dispersion microreactor A at a flow rate of 5 mL / min, while the feed flow rate of solution B was adjusted to maintain the pH of the mixture at 8.5; the resulting mixture was then held in a residence tube for 15 min to form a silica gel. The obtained gel was introduced through the left port of a tee, and solution C was introduced through the right port of the tee at a flow rate of 5 mL / min. After mixing, the mixture was introduced into the continuous phase end of the second membrane dispersion microreactor B. Simultaneously, solution D was introduced into the dispersed phase end of the second membrane dispersion microreactor B through a feed pump at a flow rate of 5 mL / min for mixing. The resulting suspension was collected through a residence pipe. The collected suspension was centrifuged and washed until the pH was neutral, dried, and ground to obtain the catalyst precursor. The precursor was calcined in a muffle furnace at 400 °C for 4 h. Then, it was reduced in a tube furnace at 400 °C under H2 atmosphere for 3 h to obtain the catalyst 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-300 -500.

[0033] Examples 28-30: Preparation of 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-300, 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-350, and 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-450 The other steps are the same as in Example 23, except that the calcination temperatures in the muffle furnace are 350 ℃, 450 ℃, and 500 ℃, respectively. Ultimately, three different materials were obtained: 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-300, 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-350, and 20-8.5Ni-1.5Ce / 0.6SiO2-8.5-400-450.

[0034] Example 31: Hydrogenation of N-benzylaniline to remove benzyl 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 1-5 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80 °C for 7 h under H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 2.

[0035] Table 2 Effect of nickel-silicon molar ratio on the reaction

[0036] As can be seen from the data in Table 2, the hydrogenolysis performance of the catalyst gradually improves as the nickel-silicon molar ratio increases from 1:0.3 to 1:0.6; however, the hydrogenolysis performance of the catalyst decreases as the nickel-silicon molar ratio further increases, and the preferred nickel-silicon molar ratio is 1:0.6.

[0037] Example 32: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 6-10 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80 °C for 7 h under H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 3.

[0038] Table 3. Effect of co-active metals on the reaction

[0039] As shown in Table 3, the introduction of metals Zr, La, Co, and Fe did not improve catalyst performance; instead, it weakened hydrogenolysis activity. However, the hydrogenolysis activity of the catalyst was improved upon the addition of the co-activating metal Ce. Ce is the preferred co-activating metal.

[0040] Example 33: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 6, 11-14 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80°C for 4 h under an H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 4.

[0041] Table 4 Effect of nickel-cerium molar ratio on the reaction

[0042] As shown in Table 4, the synergistic effect between nickel and cerium metals gradually increases as the nickel-cerium molar ratio increases from 7.5:2.5 to 8.5:1.5, and the catalyst's hydrogenolysis activity gradually improves. However, when the nickel-cerium molar ratio is further increased to 9.5:0.5, the catalyst activity decreases, and the preferred nickel-cerium molar ratio is 8.5:1.5.

[0043] Example 34: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 6, 15-18 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80°C for 4 h under an H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 5.

[0044] Table 5 Effect of pH on the reaction

[0045] As shown in Table 5, the hydrogenolysis activity of the catalyst increases as the pH increases from 5.5 to 8.5. However, the catalyst activity decreases when the pH is further adjusted to 9.5, so a pH of 8.5 is preferred for preparation.

[0046] Example 35: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 6.19-22 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80°C for 4 h under an H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 6.

[0047] Table 6 Effect of flow rate on reaction

[0048] As shown in Table 6, the hydrogenolysis performance of the catalyst gradually improves as the flow rate increases from 2.5 mL / min to 5 mL / min; however, a significant decrease in hydrogenolysis performance occurs when the flow rate is further increased to 7.5 mL / min. The preferred feed flow rate is 5 mL / min.

[0049] Example 36: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 6, 23-26 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80°C for 4 h under an H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 7.

[0050] Table 7 Effect of calcination temperature on the reaction

[0051] As shown in Table 7, the hydrogenolysis performance of the catalyst increases with increasing calcination temperature to 400 °C; however, the catalytic performance decreases when the calcination temperature is increased to 500 °C. The preferred calcination temperature is 400 °C.

[0052] Example 37: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 14.7 mg of the catalyst obtained in Examples 6, 27-30 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 80°C for 4 h under an H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography using external standard method. The reaction results are shown in Table 8.

[0053] Table 8 Effect of reduction temperature on the reaction

[0054] As shown in Table 8, the hydrogenolysis performance of the catalyst gradually improves with increasing reduction temperature; however, when the reduction temperature is further increased to 500 °C, the catalytic performance of the catalyst decreases significantly. The preferred reduction temperature is 400 °C.

[0055] Example 38: Hydrogen debenzylamine of N-benzylaniline 1.6 mmol (0.2932 g) of N-benzylaniline was added to a batch high-pressure reactor, along with 3 mL of isopropanol-water mixed solvent (volume ratio 1:1). 8.8 mg of the catalyst obtained in Example 27 was added to the reactor, which was then sealed. High-purity N2 was first purged through the reactor five times to replace the air, followed by high-purity H2 purging five times. The reaction was carried out at 90 °C for 9 h under H2 pressure of 0.1 MPa. After the reaction was complete, the mixture was cooled to room temperature, and the filtered supernatant was analyzed by high-performance liquid chromatography (HPLC) using external standard method. The conversion rate of N-benzylaniline was 94.89%, and the conversion rate of aniline was 94.62%.

[0056] Matters not covered in this invention are common knowledge.

Claims

1. A continuous preparation method for a supported nickel-based catalyst, characterized in that, The method includes the following steps: Na2SiO3 solution and sulfuric acid were fed separately into the feed pumps, and then mixed in the first membrane dispersion microreactor A at 50~70 °C. The pH of the effluent was adjusted to 5.5~8.

5. After being held in the pipeline for 10-20 minutes, a silica gel is formed. The resulting gel is then introduced through the left port of a tee, and a metal salt solution is introduced through the right port of the tee after being fed into the feed pump. The two solutions are mixed and then introduced into the continuous phase end of the second membrane dispersion microreactor B. At the same time, a Na2CO3 solution is introduced into the dispersed phase end of the second membrane dispersion microreactor B through the feed pump for mixing. After being held in the pipeline for 1-5 minutes, a catalyst suspension is obtained. The collected suspension was centrifuged, washed until the pH was neutral, dried and ground to obtain the catalyst precursor; finally, it was calcined in air at 300-500℃ for 3-5 hours and reduced in hydrogen atmosphere at 300-500℃ for 3-5 hours to obtain the target catalyst Ni-Ce / SiO2. Among them, Na2SiO3 solution, metal salt solution and Na2CO3 solution are introduced into the membrane dispersion microreactor at a flow rate ratio of 1:1:1; The flow rate of sulfuric acid is adjusted to control the pH value of the system; The flow rate of the Na2SiO3 solution was 2.5~7.5 mL / min; The concentration of the Na₂SiO₃ solution is 0.03~0.15 mol / L; the concentration of the sulfuric acid is 0.03~0.15 mol / L. In the metal salt solution, the metal salts are Ni(NO3)2 and Ce(NO3)3, with a molar ratio of Ni:Ce = 19~3:1; the total metal salt concentration is 0.05~0.25 mol / L; the molar ratio of the total metal in the metal salt solution to SiO2 in the Na2SiO3 solution is 1:0.3~1.

5. The concentration of the Na2CO3 solution is 0.10~0.50 mol / L.

2. The continuous preparation method of the supported nickel-based catalyst as described in claim 1, characterized in that, In the membrane dispersion microreactor, the stainless steel microfiltration membrane has a pore size of 0.5~5μm and a diameter of 6.5~100 mm; the residence tube is made of polytetrafluoroethylene, with an inner diameter of 1.5~2.5 mm and a length of 2.5~60 m.

3. The continuous preparation method of the supported nickel-based catalyst as described in claim 1, characterized in that, in, The concentrations of Na2SiO3·9H2O are 0.09 mol / L, H2SO4 is 0.09 mol / L, Ni(NO3)2·6H2O is 0.1275 mol / L, Ce(NO3)3·6H2O is 0.0225 mol / L, and Na2CO3 is 0.30 mol / L.

4. The continuous preparation method of the supported nickel-based catalyst as described in claim 1, characterized in that, The supported catalyst comprises an active component and a support, wherein the support is silica, and the active component is a main metal M1 or a main metal M1 and a co-metal M2; the molar ratio of the active component to the support is 1:0.3~1.5; the molar ratio of the main metal M1 to the co-metal M2 is 19~3:

1. The main metal M1 of the catalyst is Ni; the auxiliary metal M2 of the catalyst is Ce.

5. The application of the supported nickel-based catalyst prepared by the method according to claim 1, characterized in that, Used to catalyze the hydrogen debenzylation of N-benzylaniline.

6. The application as described in claim 5, characterized in that, Includes the following steps: N-Benzylaniline, isopropanol-water mixed solvent, and supported catalyst were added to a batch high-pressure reactor; the reactor was sealed, and high-purity N2 was introduced into a displacement reactor, followed by high-purity H2; H2 was introduced at 0.05~0.20 MPa, and the reaction was carried out at 70~100 °C for 4~9 h to dehydrobenzylamine; The mass ratio of N-benzylaniline to catalyst is 100~20:1; in the isopropanol-water mixed solvent, the volume ratio of the two is 1:1, and 0.5~2.0 mmol of N-benzylaniline is added for every 3 mL of mixed solvent.

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