Preparation method and application of a cobalt-based catalyst derived from post-synthetic modification of MOFs

Abstract

This invention discloses a method for preparing cobalt-based catalysts derived from MOFs and their application in the hydrogenation-alkylation tandem reaction of aromatic nitro compounds. The preparation conditions of this invention are mild, and the resulting catalysts can not only significantly improve the catalytic activity and selectivity of MOFs-derived transition metal catalysts in the hydrogenation-alkylation tandem reaction of aromatic nitro compounds, but also help to reveal the development of new methods for preparing catalysts by MOFs post-synthesis and their performance improvement mechanisms. This will lay the foundation for the industrialization of hydrogenation reactions of aromatic nitro compounds and is of great significance for the wide application of aromatic nitro compounds.

Description

Technical Field

[0001] This invention belongs to the fields of functional materials and catalysis, specifically relating to a method for preparing a cobalt-based catalyst derived from MOFs and its application in the hydrogenation-alkylation tandem reaction of aromatic nitro compounds. Background Technology

[0002] The hydrogenation-alkylation tandem reaction of aromatic compounds is an important organic synthetic method. It is commonly used to introduce alkyl groups into aromatic compound molecules, thereby generating new functionalized aromatic compounds. In this reaction, the aromatic compound is first hydrogenated. Hydrogenation converts the double bond on the aromatic ring into a saturated single bond, typically using hydrogen gas and a catalyst. This step can convert the aromatic compound into the corresponding cycloalkanes. The subsequent alkylation reaction introduces an alkyl group onto the aromatic ring. This reaction can be achieved using an alkylating agent and a catalyst. Commonly used alkylating agents include haloalkanes, alcohols, and ethers. By tandemly reacting these two reactions, an alkyl group can be introduced onto the aromatic ring, generating alkylated aromatic compounds. This reaction has wide applications in organic synthesis, playing a vital role in drug synthesis, fragrance synthesis, and materials science. In summary, the hydrogenation-alkylation tandem reaction of aromatic compounds is an important organic synthetic method for preparing aromatic compounds with novel functions. This reaction has great application potential and contributes to the development of new drugs, fragrances, and materials.

[0003] Cobalt (Co) is a transition metal whose catalytic activity and selectivity make it an ideal choice for many hydrogenation reactions. Cobalt-based catalysts can catalyze a variety of elementary reactions in hydrogenation, such as aromatic ring hydrogenation, olefin hydrogenation, and carbonyl compound hydrogenation. Cobalt-based catalysts can also be used in reactions such as hydrodeammoniation, hydrodesulfurization, and hydrocracking. The advantages of cobalt-based catalysts include their relatively low cost, abundant resources, and tunable catalytic activity. Furthermore, cobalt exhibits good catalytic activity and selectivity in some hydrogenation reactions, achieving high conversion and high yield under mild reaction conditions. However, the design and optimization of cobalt-based catalysts remains an active research area. Researchers are constantly striving to improve the activity, selectivity, and stability of cobalt-based catalysts to advance the development of hydrogenation reactions. Therefore, cobalt-based catalysts play an important role in hydrogenation reactions and have broad application potential. With further research on cobalt-based catalysts, we can expect the development and application of more new hydrogenation reaction methods.

[0004] Metal-organic frameworks (MOFs) are a class of porous materials composed of metal ions and organic ligands linked by coordination bonds. Due to their high specific surface area, porous structure, and tunable chemical composition, MOFs have been extensively studied and applied in various fields, including catalysis. MOFs can be transformed into MOF-derived catalysts through methods such as pyrolysis, solvothermal treatment, or chemical conversion. In these processes, the structure of MOFs is transformed into catalytically active sites with different functions in the gas or liquid phase. MOF-derived catalysts typically possess high specific surface area and highly controllable pore structures, enabling them to provide more active sites and increase reactivity. Furthermore, MOF-derived catalysts exhibit good chemical and thermal stability, maintaining catalytic performance under high temperature and high pressure conditions. In catalytic reactions, MOF-derived catalysts can serve as active components or catalytic substrates. For example, MOF-derived metal nanoparticles exhibit good catalytic activity and can be used in applications such as oxygen reduction reactions, electrocatalysis, and catalyst regeneration. The application potential of MOF-derived catalysts in many fields continues to be developed and explored. MOFs with specific chemical functional groups can have their properties and functions controlled by introducing different types of functional groups into their structure. These functionalized functional groups can include acidity, basicity, catalytic activity, and adsorption properties. This approach not only enhances the specific properties of MOFs but also broadens their applicability and functionality in various applications. Summary of the Invention

[0005] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0006] In view of the problems existing in the above and / or prior art, the present invention is proposed.

[0007] Therefore, the purpose of this invention is to overcome the shortcomings of the prior art and provide a method for preparing a cobalt-based catalyst derived from MOFs.

[0008] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for preparing a cobalt-based catalyst derived from MOFs, comprising,

[0009] Preparation of 1,2-cyclohexanediamine salicylaldehyde ligand;

[0010] Formulate one-dimensional functionalized lanthanide MOFs and hexamethylene-cobalt MOFs;

[0011] One-dimensional functionalized lanthanum-based MOFs were mixed with methanol and stirred until completely dissolved to obtain a methanol solution of one-dimensional functionalized lanthanum-based MOFs.

[0012] Mix hexamethylenetetramine-cobalt MOFs with methanol and stir until completely dissolved to obtain a hexamethylenetetramine-cobalt MOFs solution;

[0013] A methanol solution of one-dimensional functionalized lanthanum-based MOFs was mixed with a hexamethylenetetramine-cobalt MOFs solution, stirred, dried, and thermally decomposed under an argon atmosphere to obtain MOFs, from which a derived cobalt-based catalyst was synthesized.

[0014] In a preferred embodiment of the preparation method described in this invention, the preparation of the 1,2-cyclohexanediamine salicylaldehyde ligand comprises the following steps: mixing and stirring 20 mL of methanol with 20.0 mmol of salicylaldehyde to dissolve, obtaining solution A; mixing and dissolving 20 mL of methanol with 10.0 mmol of 1,2-cyclohexanediamine to obtain solution B; adding solution B dropwise to solution A, and continuing to add solution B until precipitation ceases; filtering, washing the precipitate with methanol, drying, and recrystallizing to obtain the 1,2-cyclohexanediamine salicylaldehyde ligand; the volume ratio of salicylaldehyde, 1,2-cyclohexanediamine, and methanol is 2.2 mL: 1.23 mL: 20 mL.

[0015] As a preferred embodiment of the preparation method described in this invention, the preparation of one-dimensional functionalized lanthanum-based MOFs and hexamethylenetetramine-cobalt MOFs is as follows: the preparation process of one-dimensional functionalized lanthanum-based MOFs is as follows: dichloromethane and methanol are mixed, 0.30 mmol of 1,2-cyclohexanediamine salicylaldehyde ligand is added, the mixture is stirred, and La(NO3)3·6H2O is added dropwise. One-dimensional functionalized lanthanum-based MOFs are obtained after 7 days; the ratio of dichloromethane to 1,2-cyclohexanediamine salicylaldehyde ligand is 8 mL: 105.0 mg.

[0016] As a preferred embodiment of the preparation method described in this invention, the preparation of one-dimensional functionalized lanthanum-based MOFs and hexamethylenetetramine-cobalt MOFs involves the following steps: dissolving 0.02 mol of Co(NO3)3·5H2O in distilled water, adding hexamethylenetetramine aqueous solution, and stirring for 12 h to obtain hexamethylenetetramine-cobalt MOFs; the ratio of Co(NO3)3·5H2O, distilled water, and hexamethylenetetramine aqueous solution is 5.8 g: 25 mL: 25 mL.

[0017] As a preferred embodiment of the preparation method described in this invention, the one-dimensional functionalized lanthanum-based MOFs are mixed with methanol and stirred until completely dissolved to obtain a one-dimensional functionalized lanthanum-based MOFs methanol solution, wherein the ratio of the one-dimensional functionalized lanthanum-based MOFs to methanol is 0.25 g: 50 mL.

[0018] As a preferred embodiment of the preparation method described in this invention, the hexamethylenetetramine-cobalt MOFs are mixed with methanol and stirred until completely dissolved to obtain a hexamethylenetetramine-cobalt MOFs solution, wherein the ratio of hexamethylenetetramine-cobalt MOFs to methanol is 67.4 mg: 10 mL.

[0019] As a preferred embodiment of the preparation method described in this invention, the following steps are performed: mixing a one-dimensional functionalized lanthanum-based MOF methanol solution with a hexamethylenetetramine-cobalt MOF solution, stirring, drying, and thermally decomposing under an argon atmosphere, wherein the stirring time is 24 h, the drying temperature is 105 °C, the pyrolysis temperature is 800 °C, the heating rate is 2 °C / min, and the pyrolysis time is 5 h.

[0020] Another objective of this invention is to overcome the shortcomings of the prior art and provide a cobalt-based catalyst derived from MOFs.

[0021] Another objective of this invention is to overcome the shortcomings of the prior art and provide an application of MOFs-derived cobalt-based catalysts in the hydrogenation-alkylation tandem reaction of nitroaromatic compounds.

[0022] Beneficial effects of this invention:

[0023] This invention attempts to synthesize one-dimensional lanthanum-based MOFs materials with unsaturated amino functional groups. Using these materials as catalyst support precursors, a one-dimensional lanthanum-based MOFs-supported hexamethylenetetramine-cobalt polymer is synthesized through the interaction of unsaturated amino functional groups with cobalt ions. This polymer is then used as a catalyst precursor in a one-step pyrolysis process to develop a method for post-synthesizing lanthanum-based MOFs-derived lanthanum hydroxide-supported cobalt catalysts for the hydrogenation-alkylation tandem reaction of aromatic nitro compounds, thereby improving the catalytic performance of cobalt-based catalysts.

[0024] This invention provides a highly efficient method for synthesizing derivatized cobalt-based catalysts after the preparation of MOFs. This method is carried out after the synthesis of one-dimensional functionalized lanthanum-based MOFs. The preparation conditions for the derivatized cobalt-based catalysts are mild, but they can significantly improve the catalytic activity and selectivity of the hydrogenation-alkylation tandem reaction. It also helps to reveal the promoting mechanism of the preparation of highly efficient transition metal catalysts by lanthanum-based MOF post-synthesis methods for hydrogenation-alkylation heterogeneous catalysis. This will lay the foundation for the application of highly efficient MOF-derived catalysts in organic industrial reactions, and is of great significance for the development and widespread application of novel supported catalysts. Attached Figure Description

[0025] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0026] Figure 1 This invention describes the entire preparation process of the catalyst Co-La(OH)3 / CN and its application in a hydrogenation-alkylation tandem reaction.

[0027] Figure 2 The XRD pattern of the catalyst Co-La(OH)3 / CN prepared in this invention is shown.

[0028] Figure 3 This is a scanning electron microscope image of the Co-La(OH)3 / CN catalyst prepared in this invention.

[0029] Figure 4 This is a transmission electron microscope (TEM) image of the Co-La(OH)3 / CN catalyst prepared in this invention.

[0030] Figure 5 This is a comparison chart of the results of Embodiment 2, Comparative Example 1, and Comparative Example 2 of the present invention.

[0031] Figure 6 To compare the results of applying the Co-La(OH)3 / CN catalyst in the hydrogenation-alkylation tandem reaction with the alkylation reaction. Detailed Implementation

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification.

[0033] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0034] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0035] Unless otherwise specified, all raw materials and reagents used in the embodiments of this invention were purchased from Aladdin Reagents.

[0036] Preparation of La(NO3)3·6H2O: Measure 20 mL of concentrated HNO3 and add it to an evaporating dish. Accurately weigh 10 g of La2O3 and add it to the evaporating dish in small, repeated additions. Heat and stir magnetically until the La2O3 is completely dissolved. Continue heating and stirring until the reaction solution slowly evaporates to dryness. Add distilled water to dissolve the precipitated solids, and continue heating and stirring until the reaction solution evaporates to dryness. Add distilled water to dissolve the solids. Repeat the above steps several times, testing the pH of the reaction solution with pH paper until the solution is nearly neutral. Stop heating, transfer the solution to a beaker, and allow it to cool and precipitate at room temperature. After several days, crystalline particles are obtained, filtered, dried, and bottled for later use.

[0037] Gas chromatograph analysis parameters:

[0038] Column box temperature control range and accuracy: 5℃ above room temperature to 450℃, with an accuracy of ±0.1℃;

[0039] Gas circuit control mode and accuracy: Electronic gas circuit control, EPC, accuracy is 0.1 kPa;

[0040] Maximum heating rate of the column oven: 120℃ / min;

[0041] Column box cooling rate: dual-duct cooling;

[0042] Maximum split ratio of splitless / splitless inlet: 4500:1;

[0043] Column oven program heating stages: Infinite.

[0044] Example 1

[0045] A method for preparing a cobalt-based catalyst derived from MOFs includes the following steps:

[0046] (1) Preparation of 1,2-cyclohexanediamine salicylaldehyde ligand:

[0047] Accurately add 20.0 mmol of salicylaldehyde (2.2 mL) to a three-necked round-bottom flask containing 20 mL of methanol, and stir thoroughly with a magnetic stirrer until completely dissolved;

[0048] Accurately transfer 10.0 mmol of 1,2-cyclohexanediamine (1.23 mL) using a pipette, dissolve it in 20 mL of methanol solution, and slowly add it dropwise to a round-bottom flask. Use a constant pressure dropping funnel and stir at room temperature for about 10 min. At this time, a light yellow precipitate will appear. Continue to add dropwise and a large amount of light yellow precipitate will be produced. Continue the reaction for about 5 h. Stop the reaction when the yellow precipitate no longer increases.

[0049] The reaction solution was filtered, and the precipitate was washed three times with methanol. The washed precipitate was then dried, and the product was recrystallized with methanol.

[0050] The 1,2-cyclohexanediamine salicylaldehyde ligand is obtained by cooling the resulting yellow solution to allow fluorescent yellow needle-like crystals to precipitate.

[0051] (2) Preparation of one-dimensional functionalized lanthanide MOFs:

[0052] One-dimensional functionalized lanthanum-based MOFs were synthesized using a solvent diffusion method. The ligand cyclohexanediamine-salicylaldehyde (0.30 mmol, 105.0 mg) was dissolved in a mixed solution containing 8 mL of dichloromethane and methanol, and the solvent diffusion rate was controlled at 20 drops / min while stirring at room temperature.

[0053] Lanthanum nitrate hexahydrate (La(NO3)3·6H2O) was added dropwise to the above solution;

[0054] One-dimensional lanthanide complexes can be obtained after 7 days.

[0055] (3) Preparation of hexamethylenetetramine-cobalt MOFs:

[0056] Cobalt nitrate pentahydrate (Co(NO3)3·5H2O) (5.8g, 0.02mol) was dissolved in distilled water (25mL), and then hexamethylenetetramine aqueous solution (25mL, 14g, 0.1mol) was added.

[0057] Stirring the resulting solution for 12 hours yields hexamethylenetetramine-cobalt MOFs.

[0058] (4) Preparation of products after the coordination reaction of one-dimensional functionalized lanthanide MOFs with hexamethylenetetramine-cobalt:

[0059] Accurately weigh 0.25 g of one-dimensional functionalized lanthanide MOFs and add them to a 100 mL round-bottom flask;

[0060] Add 50 mL of methanol and stir with a magnetic stirrer until completely dissolved;

[0061] Accurately weigh hexamethylenetetramine-cobalt (67.4 mg) and dissolve it in a beaker containing 10 mL of methanol;

[0062] The above hexamethylenetetramine-cobalt MOFs solution was slowly added dropwise to a methanol solution of one-dimensional functionalized lanthanide MOFs. The resulting mixed solution was stirred and reacted at room temperature for 24 h, and then dried at 105 °C to obtain the product of the coordination reaction between one-dimensional functionalized lanthanide MOFs and hexamethylenetetramine-cobalt.

[0063] (5) Preparation of cobalt-based catalysts derived from the product of coordination reaction between one-dimensional functionalized lanthanum-based MOFs and hexamethylenetetramine-cobalt MOFs:

[0064] The product obtained by the coordination reaction of the one-dimensional functionalized lanthanum-based MOFs with hexamethylenetetramine-cobalt MOFs was thermally decomposed under an argon atmosphere at a heating rate of 2 °C / min and a pyrolysis temperature of 800 °C for 5 h to obtain the derived cobalt-based catalyst.

[0065] Example 2

[0066] The application of MOFs-derived cobalt-based catalysts in the hydrogenation-alkylation tandem reaction of nitroaromatic compounds includes the following steps:

[0067] In a 100 mL reactor, add 100 mg of nitro aromatic compound, 50 mL of ethanol solvent, and 100 mg of derived cobalt-based catalyst;

[0068] Prior to the hydrogenation-alkylation tandem experiment, the reactor was flushed three times with N2 to remove air and with H2 to remove N2.

[0069] The reaction mixture was separated by magnetic force, and the conversion of the hydrogenation-alkylation tandem reaction catalyzed by the derived Co-based catalyst was 98% by gas chromatography analysis, with a selectivity of 99% for the product N-benzylaniline.

[0070] For the entire preparation process of the catalyst Co-La(OH)3 / CN and its application in the hydrogenation-alkylation tandem reaction, please refer to [link to relevant documentation]. Figure 1 .

[0071] like Figure 1 As shown, a one-step self-assembly of a salon-type cyclohexanediamine-salicylaldehyde organic ligand and La(NO3)3·6H2O successfully synthesized a one-dimensional lanthanide salon-type MOF containing abundant uncoordinated imine groups (-CH=N-). (Named La-H2salen) Figure 1 a).

[0072] Meanwhile, a cobalt-based (Co) MOF (named Co-hmta) was also synthesized by reacting a low-cost hexamethylenetetramine (hmta) organic ligand with Co(NO3)2·5H2O. Figure 1 a). Further, one-dimensional La-H2salen MOFs were used as supports to coordinate with Co-hmta MOFs to form a Co-hmta@La-H2salen complex ( Figure 1 b).

[0073] The obtained Co-hmta@La-H2salen complex was further pyrolyzed under an argon atmosphere to yield a Co-La(OH)3 / CN catalyst, which was used for the tandem reaction of aromatic compounds with alcohols. Figure 1 c). Catalysts derived from this unique composite structure can further improve the dispersion of active metal Co contained in Co-hmtaMOFs and enhance metal-metal interactions, thereby improving the performance of catalyzing nitroaromatics with various alcohols.

[0074] The XRD pattern of the catalyst Co-La(OH)3 / CN is shown in [reference]. Figure 2 The XRD pattern shows that the Co-La(OH)3 / CN catalyst exhibits metallic Co diffraction peaks at 2θ of 44.3°, 51.6°, and 75.9°, while the other diffraction peaks are attributed to La(OH)3, thus confirming the successful synthesis of the Co-La(OH)3 / CN catalyst.

[0075] See the scanning electron microscope image of the catalyst Co-La(OH)3 / CN. Figure 3 The scanning images show that the Co-La(OH)3 / CN catalyst has a honeycomb-like morphology with a large number of dispersed nanoparticles on its surface. This porous structure facilitates mass transfer in the tandem reaction of aromatic compounds and alcohols, thus accelerating the reaction rate.

[0076] See transmission electron microscopy image of the catalyst Co-La(OH)3 / CN. Figure 4 The transmission images show that metallic Co has a large dispersion on the surface area of ​​the Co-La(OH)3 / CN catalyst and no agglomeration occurs. This indicates that the MOF template method can effectively improve the dispersion of the active components in the catalyst.

[0077] Comparative Example 1

[0078] The difference between this comparative example and Example 2 is that the catalyst used is lanthanum oxide supported on Co catalyst, Co / La2O3.

[0079] Preparation of La2O3: The one-dimensional functionalized lanthanide MOFs (La-H2salen) (200mg) obtained above were calcined in air at a heating rate of 2℃ / min and a pyrolysis temperature of 550℃ for 6 hours to obtain the La2O3 support.

[0080] Accurately weigh Co(NO3)2·5H2O (20.4 mg) and dissolve it in a beaker containing 10 mL of methanol;

[0081] The Co(NO3)2·5H2O solution was slowly added dropwise to the La2O3 support, and the resulting complex was dried at 105℃ to obtain the La2O3-supported Co(NO3)2·5H2O product.

[0082] The obtained La2O3-supported Co(NO3)2·5H2O complex was further calcined in air to obtain a Co / La2O3 catalyst, which was used for the tandem reaction of aromatic compounds with alcohols.

[0083] In a 100 mL reactor, a nitro aromatic compound (100 mg), ethanol solvent (50 mL), and lanthanum oxide-supported Co catalyst, Co / La2O3 (100 mg), were added.

[0084] Prior to the hydrogenation-alkylation tandem experiment, the reactor was flushed three times with N2 to remove air and with H2 to remove N2.

[0085] The reaction mixture was separated by magnetic force, and the conversion of the hydrogenation-alkylation tandem reaction catalyzed by the catalyst was determined by gas chromatography to be 90%, with 54% aniline selectivity and 46% N-benzylaniline selectivity.

[0086] Comparative Example 2

[0087] The difference between this comparative example and Example 2 is that no catalyst was used.

[0088] Add 100 mg of nitro aromatic compound and 50 mL of ethanol solvent to a 100 mL reactor;

[0089] Prior to the hydrogenation-alkylation tandem experiment, the reactor was flushed three times with N2 to remove air and with H2 to remove N2.

[0090] The reaction mixture was separated by magnetic force, and the conversion and yield of the hydrogenation-alkylation tandem reaction were both found to be 0 by gas chromatography.

[0091] For a comparison of the reaction results of Example 2 with Comparative Examples 1 and 2, please refer to [link / reference]. Figure 5 The comparison results show that the reaction did not occur without the catalyst, indicating that the catalyst is crucial for the entire tandem reaction. The Co-La(OH)3 / CN catalyst prepared in Example 1 achieved a catalytic conversion rate of 98% in the hydrogenation-alkylation tandem reaction, with a selectivity of 99% for the product N-benzylaniline. Its performance is significantly higher than that of the conventional Co / La2O3 catalyst, which achieved a 90% nitrobenzene conversion, a 54% aniline selectivity, and a 46% N-benzylaniline selectivity.

[0092] For a comparison of the results of applying the Co-La(OH)3 / CN catalyst in the hydrogenation-alkylation tandem reaction of nitrobenzene and benzyl alcohol, and the alkylation reaction of aniline and benzyl alcohol, see [link to relevant documentation]. Figure 6 .from Figure 6 The comparative results show that, under the same reaction conditions, the developed Co-La(OH)3 / CN catalyst achieves a 99% conversion of nitrobenzene and a 99% selectivity for N-benzylaniline in the hydrogenation-alkylation tandem reaction of nitrobenzene and benzyl alcohol. In the alkylation of aniline and benzyl alcohol, the Co-La(OH)3 / CN catalyst achieves an 89% conversion of aniline and a 89% selectivity for N-benzylaniline. These results indicate that the alkylation of aniline and benzyl alcohol is the rate-determining step in the entire hydrogenation-alkylation tandem reaction.

[0093] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the present invention.

Claims

1. A method for preparing a cobalt-based catalyst derived from MOFs, characterized in that: include, Preparation of 1,2-cyclohexanediamine salicylaldehyde ligand; Formulate one-dimensional functionalized lanthanide MOFs and hexamethylene-cobalt MOFs; One-dimensional functionalized lanthanum-based MOFs were mixed with methanol and stirred until completely dissolved to obtain a methanol solution of one-dimensional functionalized lanthanum-based MOFs. Mix hexamethylenetetramine-cobalt MOFs with methanol and stir until completely dissolved to obtain a hexamethylenetetramine-cobalt MOFs solution; A methanol solution of one-dimensional functionalized lanthanum-based MOFs was mixed with a hexamethylenetetramine-cobalt MOFs solution, stirred, dried, and thermally decomposed under an argon atmosphere to obtain MOFs, which were then used to synthesize a derived cobalt-based catalyst. The preparation process of the one-dimensional functionalized lanthanum-based MOFs is as follows: dichloromethane and methanol are mixed, 0.30 mmol of 1,2-cyclohexanediamine salicylaldehyde ligand is added, the solvent diffusion rate is controlled at 20 drops / min, the mixture is stirred, and La(NO3)3·6H2O is added dropwise. One-dimensional functionalized lanthanum-based MOFs are obtained after 7 days. The ratio of dichloromethane to 1,2-cyclohexanediamine salicylaldehyde ligand is 8 mL: 105.0 mg. The process involves mixing a one-dimensional functionalized lanthanum-based MOF methanol solution with a hexamethylenetetramine-cobalt MOF solution, stirring, drying, and then thermally decomposing the mixture under an argon atmosphere. The stirring time is 24 h, the drying temperature is 105 °C, the pyrolysis temperature is 800 °C, the heating rate is 2 °C / min, and the pyrolysis time is 5 h. The hydrogenation-alkylation tandem reaction catalyzed by the derived cobalt-based catalyst can achieve a conversion rate of up to 98%.

2. The preparation method according to claim 1, characterized in that: The preparation process for the 1,2-cyclohexanediamine salicylaldehyde ligand is as follows: 20 mL of methanol and 20.0 mmol of salicylaldehyde are mixed and stirred to dissolve, yielding solution A; 20 mL of methanol and 10.0 mmol of 1,2-cyclohexanediamine are mixed and dissolved to obtain solution B; solution B is added dropwise to solution A, and the addition continues until no further precipitation occurs; the mixture is filtered, the precipitate is washed with methanol, dried, and recrystallized to obtain the 1,2-cyclohexanediamine salicylaldehyde ligand; the volume ratio of salicylaldehyde, 1,2-cyclohexanediamine, and methanol is 2.2 mL: 1.23 mL: 20 mL.

3. The preparation method according to claim 1, characterized in that: The preparation of one-dimensional functionalized lanthanum-based MOFs and hexamethylenetetramine-cobalt MOFs is as follows: 0.02 mol of Co(NO3)3·5H2O is dissolved in distilled water, hexamethylenetetramine aqueous solution is added, and the mixture is stirred for 12 h to obtain hexamethylenetetramine-cobalt MOFs; the ratio of Co(NO3)3·5H2O, distilled water and hexamethylenetetramine aqueous solution is 5.8 g: 25 mL: 25 mL.

4. The preparation method according to claim 1, characterized in that: The one-dimensional functionalized lanthanum-based MOFs are mixed with methanol and stirred until completely dissolved to obtain a one-dimensional functionalized lanthanum-based MOFs methanol solution, wherein the ratio of the one-dimensional functionalized lanthanum-based MOFs to methanol is 0.25 g: 50 mL.

5. The preparation method according to claim 1, characterized in that: The hexamethylenetetramine-cobalt MOFs are mixed with methanol and stirred until completely dissolved to obtain a hexamethylenetetramine-cobalt MOFs solution, wherein the ratio of hexamethylenetetramine-cobalt MOFs to methanol is 67.4 mg: 10 mL.

6. The MOFs prepared by any one of the preparation methods described in claims 1 to 5 are then used to synthesize a derived cobalt-based catalyst.

7. The application of the MOFs-derived cobalt-based catalyst as described in claim 6 in the hydrogenation-alkylation tandem reaction of nitroaromatic compounds.

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