Supported catalyst and application thereof in synthesis of 1, 3-cyclohexanedione

Abstract

The invention provides a supported catalyst and application thereof in synthesis of 1, 3-cyclohexanedione, and belongs to the technical field of chemical synthesis. The preparation method comprises the following steps: sequentially adding Zr salt, Ni salt, Ce salt and Cu salt into a citric acid aqueous solution in a stirring state to obtain a clear mixed solution; stirring the mixed solution in a water bath until the mixed solution is gel-like, and drying to obtain dry gel; calcining the xerogel to obtain a precursor, and reducing the precursor in H2 / Ar airflow to obtain the supported catalyst. The supported catalyst is used for synthesis of 1, 3-cyclohexanedione, and has the advantages of high selectivity, few byproducts and the like.

Description

Technical Field

[0001] This application relates to a supported catalyst and its application in the synthesis of 1,3-cyclohexanedione, belonging to the field of chemical synthesis technology. Background Technology

[0002] 1,3-Cyclohexanedione is an important chemical intermediate with various applications in the synthesis of valuable compounds, widely used in the synthesis of pharmaceuticals, pesticides, cosmetics, and polymer additives. Depending on the availability of raw materials, it is generally manufactured in two ways: The first method is the aldol condensation method, which uses γ-acylcarboxylic acid or α,β-unsaturated carboxylic acid esters and ketones as raw materials. The 1,3-cyclohexanedione is generated by reacting with a strong basic condensing agent through intramolecular or intermolecular condensation (US 4695673 A1; 1987).

[0003] The second catalytic hydrogenation method, such as the selective hydrogenation of resorcinol using a Pd / C catalyst to synthesize 1,3-cyclohexanedione, is also the main method for producing 1,3-cyclohexanedione. However, due to over-hydrogenation, this process usually produces byproducts such as 3-hydroxycyclohexanone and 1,3-cyclohexanediol (Chem. Commun, 2008, 8, 999). Alternatively, Raney nickel catalysts can be used for the selective hydrogenation of resorcinol to synthesize 1,3-cyclohexanedione, but the number of cycles is only 2-3. Although the cost is low, catalyst recovery and storage are problems, and Raney nickel is flammable in air.

[0004] Therefore, achieving high selectivity for 1,3-cyclohexanedione, especially with increased resorcinol conversion, remains a significant challenge. Summary of the Invention

[0005] In view of this, this application first provides a novel catalyst for hydrogenation reactions, which not only reduces the formation of byproducts, but also has the advantages of low cost, high cycle life, and stable catalytic performance.

[0006] Specifically, this application is implemented through the following scheme: A supported catalyst is prepared by the following steps: Step 1: While stirring, add Zr salt, Ni salt, Ce salt, and Cu salt sequentially to the citric acid aqueous solution to obtain a clear mixed solution; Step 2: Stir the mixed solution in a water bath until it becomes gel-like, then dry it to obtain a dry gel; Step 3: The dry gel is calcined to obtain the precursor, which is then reduced in an H2 / Ar gas stream to obtain the supported catalyst.

[0007] Furthermore, as a preferred option: The concentration of the citric acid aqueous solution is 5~10g / ml.

[0008] The Zr salt, Ni salt, Ce salt, and Cu salt mentioned are all nitrates.

[0009] The addition ratio of Zr salt, Ni salt, Ce salt, and Cu salt is 10:0.8~1.2:0.4~0.6:0.4~0.6, preferably 10:1:0.5:0.5.

[0010] The calcination is divided into two stages. The first stage is calcination at 300~360℃ for 1~2 hours. After the first stage of calcination is completed, the temperature is cooled to room temperature and then calcined at 480~550℃ for 3~6 hours.

[0011] The reduction temperature is 300~500℃.

[0012] The above-mentioned supported catalyst, with nickel as the main component, can significantly reduce the cost of the catalyst. The catalyst exhibits extremely high selectivity, conversion rate and high reusability in the catalytic hydrogenation of resorcinol, reduces by-products generated due to excessive hydrogenation, has a simple process, is easy to store, and has a much higher number of cycles than Raney nickel.

[0013] Meanwhile, this application also provides the application of the above-mentioned supported catalyst in the synthesis of 1,3-cyclohexanedione: resorcinol, organic base, water and supported catalyst are added to a high-pressure reactor, argon and hydrogen are introduced for replacement, catalytic hydrogenation reaction is carried out, the supported catalyst is removed, protic acid is added and stirred to react, the resulting solution is rotary evaporated and vacuum dried to obtain 1,3-cyclohexanedione.

[0014] Preferred: The amount of the supported catalyst added is 5-10% of the mass of resorcinol, with 6% being preferred.

[0015] The molar ratio of resorcinol to organic base is 1:0.5~2, with 1:1 being preferred.

[0016] The organic base is sodium hydroxide, potassium hydroxide, or lithium hydroxide, with sodium hydroxide being preferred.

[0017] The catalytic hydrogenation reaction temperature is 60~100℃, and the reaction pressure is 1~3MPa. The reaction effect is best at 80℃ and 1.5MPa.

[0018] The protic acid is hydrochloric acid, nitric acid, or sulfuric acid, with hydrochloric acid being preferred.

[0019] The catalyst of this application reduces costs while exhibiting high activity for the reduction of 1,3-cyclohexanedione, enabling the synthesis of 1,3-cyclohexanedione with high yield and high purity, thus demonstrating the best economic advantages. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application.

[0021] Figure 1 This is the XRD pattern of catalyst A in this application.

[0022] Figure 2 The figure shows the XPS spectrum of catalyst A in this application. Part (a) is the full XPS spectrum of catalyst A, part (b) is the XPS spectrum of Zr, part (c) is the XPS spectrum of Ce, part (d) is the XPS spectrum of Cu, part (e) is the XPS spectrum of Ni, and part (f) is the XPS spectrum of O.

[0023] Figure 3 The image shows the SEM spectra of catalyst A in this application. Part (a) is the SEM spectra of catalyst A at a scale bar of 20 μm, part (b) is the SEM spectra of catalyst A at a scale bar of 10 μm, part (c) is the SEM spectra of catalyst A at a scale bar of 2 μm, and part (d) is the SEM spectra of catalyst A at a scale bar of 1 μm.

[0024] Figure 4 The image shows the EDS spectrum of catalyst A in this application. Part (a) is the Zr element distribution of catalyst A, part (b) is the O element distribution of catalyst A, part (c) is the Ni element distribution of catalyst A, part (d) is the Cu element distribution of catalyst A, part (e) is the Ce element distribution of catalyst A, and part (f) is the total number of distributions of catalyst A.

[0025] Figure 5 The liquid chromatogram of 1,3-cyclohexanedione synthesized in Application Example 1 is shown.

[0026] Figure 6 This is a high-resolution spectrum of 1,3-cyclohexanedione synthesized in Application Example 1. Detailed Implementation

[0027] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the technical solutions in the embodiments of this application will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit the technical solutions of this application. All other embodiments obtained by those skilled in the art based on the embodiments in this application without creative effort are within the scope of protection of this application.

[0028] Example 1

[0029] This embodiment provides a supported catalyst. Taking the preparation of 1g of catalyst as an example, the preparation process and ingredients are as follows: S1. Add 1.814g of citric acid and 30mL of deionized water to the reaction vessel. The citric acid dissolves in the deionized water to obtain an aqueous solution of citric acid.

[0030] S2, under stirring, add 1.307g Zr(NO3)4·5H2O, 0.195g Ni(NO3)2·6H2O, 0.126g Ce(NO3)3·6H2O, and 0.076g Cu(NO3)2·3H2O one by one in the order of Zr→Ni→Ce→Cu, ensuring that the previous one is completely dissolved before adding the next one, to obtain a clear mixed solution.

[0031] S3. Place the mixed solution in an 80°C water bath, heat with the oven open and stir continuously. Water gradually evaporates, and the solution viscosity increases. As water decreases and citric acid condenses, the system transforms from solution → sol → gel. Continue heating and evaporation until a viscous, non-flowing gel, i.e., a wet gel, is formed.

[0032] S4. Transfer the wet gel to an oven and dry it at 110°C for 12 hours. The wet gel further loses water and shrinks in volume, becoming a porous, loose, and brittle solid, called a dry gel.

[0033] S5 involves pre-calcining the dry gel in a muffle furnace at 350°C for 2 hours to slowly and thoroughly remove organic matter such as citric acid, thus preventing material structure damage caused by instantaneous combustion under high temperature conditions.

[0034] S6. After the furnace temperature cools down, the pre-calcined powder is calcined again at 500℃ for 4 hours to form a stable tetragonal phase of ZrO2 and convert the metal into its corresponding oxides (NiO, CuO, CeO2), which are catalyst precursors.

[0035] S7, the catalyst precursor was reduced in an H2 / Ar (volume ratio 5:95) gas stream. The reduction procedure was as follows: the temperature was increased from room temperature to 400°C at a rate of 3°C / min, held at that temperature for 3 hours, and then cooled to 25°C. The resulting product was designated as catalyst A and denoted as Cu-Ce-NiO / ZrO2.

[0036] The XRD pattern of catalyst A is shown below. Figure 1As shown, obvious diffraction peaks were found around 30°, 35°, 37°, 43°, 50°, 60°, 63°, and 64°, corresponding to the (111), (200), (220), (311), and (222) planes of tetragonal zirconium oxide and the (111), (200), and (220) planes of nickel oxide, respectively. This confirms the presence of the support zirconium oxide and nickel oxide. The peaks of Cu and Ce were not observed because the particles are small and well dispersed, and most of them are nanoparticles, so their diffraction peaks were not detected.

[0037] XPS plot of catalyst A as shown Figure 2 As shown: Most of the oxygen is lattice oxygen, which is the oxygen ion that constitutes the crystal structure of metal oxide catalysts. Its core role is to adjust the surface acidity and basicity, thereby controlling the reaction selectivity. Lattice oxygen (O 2- A proton (H) can be extracted from the hydroxyl group (-OH) of the enol intermediate. + It transforms itself into a surface hydroxyl group (OH). 2- Simultaneously, it enables the carbon atoms of the intermediate to form C=O double bonds, completing the transformation from the enol form to the ketone form. Defect oxygen and adsorbed oxygen are also present, their content second only to lattice oxygen. Defect oxygen usually coexists with oxygen vacancies and serves as active sites on the catalyst surface, its main function being to activate hydrogen. It facilitates the polarization and adsorption of the benzene ring of resorcinol, especially the electron-rich phenolic hydroxyl group, making it more susceptible to attack. Adsorbed oxygen can increase the interaction strength between the metal and the oxide support (such as ZrO2). Zirconium only has one peak, indicating that the zirconium species on the sample surface is mainly ZrO2, primarily existing as a support. In this catalyst, the theoretical Ni loading is 10 wt%, with almost all Ni existing in the form of nickel oxide. Cu and Ce metals are first loaded onto NiO, then onto tetragonal zirconium oxide, resulting in almost no visible Ni in the spectrum. 0 It may be better dispersed and used for efficient activation of H2 and catalytic hydrogenation, while Cu is used as Cu 0 It exists in the form of nanoparticles and is also used to activate hydrogen gas; it can be obtained from Cu. 0 Surface overflow to adjacent Cu 2+ At the site or on the support, Cu participates in the hydrogenation step. 2+ It selectively adsorbs and activates resorcinol. Furthermore, Ce exists primarily in the trivalent and tetravalent states. The magic of cerium dioxide lies in the ease with which oxygen vacancies are formed in its crystal structure, accompanied by the generation of Ce. 3+ To maintain electroneutrality Ce 3+ and Ce 4+ It does not exist in isolation, but rather dynamically cycles within the reaction. Ce 3+ As an "electronic reservoir": Ce 3+Electrons can be donated to the supported metal nanoparticles Ni and Cu. The inter-valence of Ce is relatively easy, which can both modulate the electronic structure of Ni, weakening its strong adsorption to carbonyl groups and fundamentally improving selectivity, and also donate electrons to Cu, helping to maintain Cu's valence. 0 The active metallic state.

[0038] SEM images of catalyst A are shown below. Figure 3 As shown in the SEM image at a 20 μm scale, catalyst A exhibits predominantly plate-like and blocky structures, displaying a uniform and dense particle packing structure without obvious macroscopic pores or large-sized agglomerates. The catalyst particles are relatively uniformly distributed on the substrate, indicating good precursor dispersion during preparation and the absence of localized excessive aggregation. The dense structure at low magnification indicates that the material possesses good overall formability, providing a continuous distribution basis for the catalytic reaction. The interaction between active components such as Cu, Ce, and NiO and the ZrO2 support, as well as the surface energy driven during calcination, promotes the spontaneous aggregation of nanoparticles into clusters. At high magnification, minute depressions and protrusions are visible on the surface; these structural defects can serve as active centers for the catalytic reaction, enhancing the adsorption and activation capabilities of the reactants.

[0039] EDS of catalyst A as follows Figure 4 As shown, Zr, O, Ni, Cu, and Ce all exhibit uniform signal distribution within the observation region, with no obvious elemental segregation or local enrichment. This indicates that during catalyst preparation, the active components and the support achieved good mixing and dispersion, providing uniform active sites for the catalytic reaction. Zr and O showed the highest peak intensities, consistent with the positioning of ZrO2 as the main support; Ni, Cu, and Ce showed moderate peak intensities and stable proportions, consistent with the designed multi-component composite catalyst composition. This uniform elemental distribution effectively promotes the synergistic effect among Cu, Ce, and NiO, further demonstrating the catalyst's excellent catalytic performance.

[0040] Application Example 1

[0041] Catalyst A was applied to the synthesis of 1,3-cyclohexanedione, as follows: In a high-pressure reactor, 0.4 g of resorcinol, 0.04 g of catalyst A, 0.1454 g of sodium hydroxide, and 2 mL of water were added sequentially. The air in the reactor was first replaced with argon, and then the argon was replaced with hydrogen. The catalytic hydrogenation reaction was carried out at 80 °C and 1.5 MPa for 3 h, and then the reaction was stopped. Catalyst A was removed by centrifugation to obtain a 1,3-cyclohexanedione solution. After rotary evaporation, the solution was dried in a vacuum drying oven at 50 °C for 8 h to obtain the product 1,3-cyclohexanedione, with a product yield of 99.9%.

[0042] The synthesis of 1,3-cyclohexanedione was carried out using catalyst A. Through the synergistic effect of the metal oxide support, the combination of Ce and Cu, and the reducing power of Ni and Cu, resorcinol was reduced to 1,3-cyclohexanedione. At the same time, the mutual inhibition prevented it from being excessively hydrogenated to an alcohol.

[0043] The 1H NMR spectrum shows peak positions and hydrogen counts consistent with those in the literature, with no excess or deficiency of hydrogens, indicating no excessive hydrogenation products and the absence of alcohols and starting phenols, thus confirming that this is the desired product. (Including liquid chromatography) Figure 3 The peak position in the sample (6.234 min) was exactly the same as that in the standard sample. In addition, we also measured the high-resolution spectrum of the product. Figure 4 The main product peak was measured to be as high as approximately 99%, proving the product is very pure. Furthermore, [M+H]... + The amount was 113.0600, consistent with 1,3-cyclohexanedione. The above spectrum proves that the 1,3-cyclohexanedione product obtained using catalyst A has very ideal purity.

[0044] Example 2

[0045] This embodiment has the same setup as Embodiment 1, except that in S7, the reduction reaction temperature is replaced by 300℃ and 500℃ respectively, and the resulting catalysts are denoted as catalyst B and catalyst C respectively.

[0046] Example 3

[0047] The setup in this embodiment is the same as in embodiment 1, except that in S2, only 1.307g Zr(NO3)4·5H2O and 0.195g Ni(NO3)2·6H2O are added, and no other metal precursors are added. The resulting catalyst is denoted as catalyst D.

[0048] Catalysts A, B, C, and D, along with commercial catalysts Pd / C, Rh / C, Raney nickel, and PtO2, were applied to the synthesis of 1,3-cyclohexanedione, and their catalytic effects were tested. The results are shown in Table 1.

[0049] Table 1: Comparison of catalytic performance of different types of catalysts .

[0050] The amount of metal loaded on the catalyst, the type of metal loaded, and the support all have a significant impact on the catalyst's performance. Table 1 shows that: 1) Changing the calcination temperature has little effect on the conversion rate and selectivity, with 350℃ being optimal. Changing the reduction temperature will alter both substrate conversion and product selectivity, but under the same conditions, within the reduction temperature range of 300-500℃, the substrate conversion and product selectivity of catalysts A, B, and C can all remain above 90%. The preferred reduction reaction temperature is 400-500℃, at which point the substrate conversion remains above 65.6% and the product selectivity above 94.6%, with the catalyst obtained at 400℃ showing the best synthesis effect. Catalysts prepared under different process conditions can all effectively catalyze the synthesis of 1,3-cyclohexanedione, with catalyst A showing the best catalytic effect.

[0051] 2) Regarding catalyst composition: When nickel is used as the precursor alone, such as in the synthesis of 1,3-cyclohexanediol using catalyst D, the product is more likely to be directly converted to 1,3-cyclohexanediol, with a substrate conversion rate reaching 99.3%. However, the product selectivity is only 38.6%. Adding Co metal as an inhibitor of excessive reaction yields exceptionally significant results, increasing the product selectivity from 38.6% with catalyst D to 98.8% with catalyst A, and maintaining a high conversion rate above 99%. Especially for preventing excessive hydrogenation to 1,3-cyclohexanediol or ring-opening reactions, the catalytic system of this application with added Co metal greatly suppresses this situation.

[0052] 3) Compared with commercially available catalysts such as Pd / C and Raney nickel, it can be seen that while some commercial catalysts show good conversion effects, their product selectivity is far lower than that of the catalyst prepared in this application. Furthermore, the use of expensive metals not only increases the preparation cost but also makes pure palladium catalysis prone to over-hydrogenation, directly generating alcohols or ring-opening products, and making catalytic activity difficult to control. Raney nickel catalysts present storage challenges, are unstable, and have lower catalytic activity than our catalyst. In contrast, the catalyst in this application utilizes the synergistic effect of nickel and cobalt to hydrogenate the double bond, while cobalt metal antagonizes nickel metal, limiting over-hydrogenation to prevent the formation of ring-opening products and alcohols.

[0053] Application Example 2

[0054] The settings in this application example are the same as those in application example 1, except that the amount of catalyst A added is replaced with 0.01g, 0.02g, and 0.03g, respectively. The results are shown in Table 2.

[0055] Table 2: Effect of different catalyst dosages on the synthesis efficiency of 1,3-cyclohexanedione .

[0056] As can be seen from Table 2, under the same experimental conditions, the reaction yield is the highest when the amount of catalyst A is 0.04 g. Reducing the amount of catalyst decreases the yield, but the catalysis will not be over-hydrogenated and the selectivity is still relatively high. When the catalyst is insufficient, the catalytic ability decreases by 7.5%-10.0% and the catalytic effect is the best.

[0057] Application Example 3

[0058] This application example mainly investigates the effect of the ratio of resorcinol to sodium hydroxide on the synthesis of 1,3-cyclohexanedione. The settings are the same as in application example 1, except that the molar ratio of resorcinol to sodium hydroxide is replaced by 1:0.5, 1:1.5, and 1:2 respectively. The results are shown in Table 3.

[0059] Table 3: Effect of different molar ratios of resorcinol and sodium hydroxide on the reaction .

[0060] As can be seen from Table 3, under the same process conditions, the substrate conversion and product selectivity are the highest when the molar ratio of resorcinol to sodium hydroxide is 1:1.

[0061] Application Example 4

[0062] This application example examines the effect of reaction temperature on the synthesis of 1,3-cyclohexanedione. The settings are the same as in application example 1, except that the reaction temperature for catalytic hydrogenation is replaced by 60°C, 70°C, 90°C, and 100°C, respectively. The results are shown in Table 4.

[0063] Table 4: Effect of different temperatures on the reaction

[0064] .

[0065] As shown in Table 4, the conversion rate reaches its peak at a reaction temperature of 80℃. Above 80℃, the conversion rate no longer increases, but the amount of byproducts gradually increases, including alcohol byproducts and ring-opening products. The product selectivity decreases from 98.8% at 80℃ to 85.3% at 90℃ and 80.4% at 100℃. Therefore, the catalytic environment is optimal at 80℃.

[0066] Application Example 5

[0067] This application example mainly investigates the effect of reaction pressure on the synthesis of 1,3-cyclohexanedione. The settings are the same as in application example 1, except that the reaction pressure of catalytic hydrogenation is replaced by 1 MPa, 2 MPa and 3 MPa respectively. The results are shown in Table 5.

[0068] Table 5: Effect of different pressures on the reaction

[0069] .

[0070] As shown in Table 5, the conversion rate reaches a maximum of 99.9% at a reaction pressure of 1.5 MPa. Further increasing the pressure does not increase the conversion rate, but the amount of byproducts gradually increases, with the formation of alcohol byproducts or ring-opening products. The product selectivity decreases from 98.8% at 1.5 MPa to 90.8% at 2 MPa and 60.3% at 3 MPa. At pressures below 1.5 MPa, the conversion is incomplete, with some raw materials remaining unreacted. At 1 MPa, the substrate conversion rate is only 80.3%, while the product selectivity remains at 99.3%.

[0071] Therefore, the catalytic environment is optimal at 1.5 MPa.

[0072] Application Example 6

[0073] This application example primarily explores the impact of catalyst recycling on the reaction, as detailed below: The catalyst A obtained by centrifugation in Application Example 1 (washed several times with deionized water and ethanol, dried in an oven, and activated for 1 hour) was used in the next reaction: In a high-pressure reactor, 0.4 g of resorcinol, approximately 0.04 g of catalyst A recovered in Example 1, and 0.1454 g of sodium hydroxide were added sequentially, followed by 2 mL of water. After purging with argon and hydrogen, catalytic hydrogenation was carried out at 80 °C and 2 MPa. The reaction was stopped after 3 h, and catalyst A was recovered by centrifugation to obtain a 1,3-cyclohexanedione solution. After rotary evaporation, the solution was dried in a vacuum drying oven at 50 °C for 8 h to obtain the product 1,3-cyclohexanedione.

[0074] The recovered catalyst A was washed three times with deionized water and ethanol, dried in an oven, and then reduced in a tube furnace for 1 hour before being added back into the reaction. The performance of the catalyst for reuse was investigated, and the results are shown in Table 6.

[0075] Table 6: Reuse Performance of Catalyst A .

[0076] As can be seen from Table 6, the catalyst still exhibits high activity after being reused 20 times, indicating that the Cu-Ce-NiO / ZrO2 catalyst synthesized in this application has good reproducibility.

[0077] In summary: This application not only provides a novel supported catalyst, but also presents a highly selective and high-conversion synthetic route for 1,3-cyclohexanedione. This synthetic route reduces production costs and solves the problems of excessive by-products and excessive hydrogenation of the benzene ring in existing processes. It ensures complete hydrogenation of the reaction substrate and safety of the reaction conditions. Furthermore, the post-processing is simple, the catalyst is easy to prepare, reusable, and inexpensive.

[0078] The embodiments described above are merely examples of several feasible implementations of this application. While the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. Furthermore, the embodiments are not intended to limit the scope of protection outlined in the claims. Those skilled in the art can make various modifications and improvements without departing from the concept of this application. All equivalent implementations or changes that do not depart from the scope of this application should be included in the technology of this application.

Claims

1. A supported catalyst characterized in that, The preparation steps are as follows: Step 1: While stirring, add Zr salt, Ni salt, Ce salt, and Cu salt sequentially to the citric acid aqueous solution to obtain a clear mixed solution; Step 2: Stir the mixed solution in a water bath until it becomes gel-like, then dry it to obtain a dry gel; Step 3: The dry gel is calcined to obtain the precursor, which is then reduced in an H2 / Ar gas stream to obtain the supported catalyst.

2. The supported catalyst according to claim 1, characterized in that: The concentration of the citric acid aqueous solution is 5~10g / ml.

3. The supported catalyst according to claim 1, characterized in that: The Zr salt, Ni salt, Ce salt, and Cu salt mentioned are all nitrates.

4. The supported catalyst according to claim 1, characterized in that: The addition ratio of Zr salt, Ni salt, Ce salt, and Cu salt is 10:0.8~1.2:0.4~0.6:0.4~0.

6.

5. The supported catalyst according to claim 1, characterized in that: The calcination is divided into two stages. The first stage is calcination at 300~360℃ for 1~2 hours. After the first stage of calcination is completed, the temperature is cooled to room temperature and then calcined at 480~550℃ for 3~6 hours.

6. The supported catalyst according to claim 1, characterized in that: The reduction temperature is 300~500℃.

7. The application of the supported catalyst according to claim 1 in the synthesis of 1,3-cyclohexanedione, characterized in that: Resorcinol, an organic base, water, and a supported catalyst were added to a high-pressure reactor. After purging with argon and then hydrogen, a catalytic hydrogenation reaction was carried out. The supported catalyst was removed, and a protic acid was added to stir the reaction. The resulting solution was then rotary evaporated and vacuum dried to obtain 1,3-cyclohexanedione.

8. The application according to claim 7, characterized in that: The amount of the supported catalyst added is 5-10% of the mass of resorcinol, and the molar ratio of resorcinol to organic base is 1:0.5-2.

9. The application according to claim 7, characterized in that: The catalytic hydrogenation reaction is carried out at a temperature of 60~100℃ and a pressure of 1~3MPa.

10. The application according to claim 7, characterized in that: The protic acid is hydrochloric acid, nitric acid, or sulfuric acid.

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