Hydrotalcite-loaded trimetal catalyst, preparation method and application thereof, and method for catalyzing hydrogenation of aldehyde compounds

Abstract

The invention provides a hydrotalcite-loaded trimetal catalyst, a preparation method and application thereof, and a method for catalyzing hydrogenation of aldehyde compounds, and particularly relates to the technical field of catalytic synthesis. The hydrotalcite supported trimetal catalyst comprises a CuAB-LDHs (layered double hydroxides) type hydrotalcite carrier and an active component which is supported on the CuAB-LDHs type hydrotalcite carrier, wherein the active component comprises metal elements Cu, A and B; a and B are cheap metal elements. According to the catalyst, active components are uniformly anchored on a hydrotalcite carrier, so that the advantages of high specific surface area, rich surface hydroxyl and strong metal-carrier interaction of hydrotalcite are fully played, and the synergistic catalytic effect among three metals is also realized. According to the catalyst structure, the active site exposure degree and the electron transmission capacity of the catalyst are remarkably improved, and the adsorption and activation efficiency of reactant molecules on the surface of the catalyst is enhanced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of catalytic synthesis, in particular to a hydrotalcite-supported trimetallic catalyst, a preparation method and application thereof, and a method for catalyzing hydrogenation of aldehyde compounds. BACKGROUND

[0002] At present, the preparation of furfuryl alcohol by liquid-phase hydrogenation of furfural mainly adopts copper-based catalysts, and the catalytic reaction is carried out in a high-pressure reaction kettle. Although the traditional copper-chromium (Cu-Cr) catalyst has high catalytic activity and selectivity (the selectivity of furfuryl alcohol can reach more than 98%), it has the problems of high toxicity of chromium element, difficult treatment of waste catalyst, easy environmental pollution, and the like, and the chromium resource is scarce and the cost is high, which does not meet the requirements of green and sustainable development. In addition, part of copper-silicon catalysts are prone to copper species loss or sintering during use, resulting in poor stability and difficult recycling of the catalyst.

[0003] In recent years, researchers have been committed to developing non-noble metal, non-toxic and high-efficiency alternative catalyst systems. Although it has been reported that nickel, cobalt or noble metal palladium is used as an active component, the former often accompanies excessive hydrogenation or ring-opening side reactions, resulting in a decrease in selectivity; and the latter is limited in industrial application due to high cost. At the same time, many catalytic systems still rely on harsh reaction conditions such as high temperature (> 170°C) and high pressure (> 4 MPa), which not only puts higher requirements on equipment safety, but also significantly increases energy consumption and production cost.

[0004] More importantly, the existing catalysts generally have the problems of low dispersion of metal active centers, easy agglomeration and deactivation, lack of acid-base synergistic site regulation, and the like, which leads to easy adsorption and poisoning of the catalyst by oxygen-containing products (such as alcohols) in the catalytic process, affecting the catalytic efficiency and service life. Therefore, how to construct a non-noble metal catalyst with high activity, high selectivity, good stability and excellent substrate adaptability has become a key challenge to realize efficient and green hydrogenation conversion of furfural.

[0005] In view of this, the present application is proposed. SUMMARY

[0006] The present application aims to provide a hydrotalcite-supported trimetallic catalyst, a preparation method and application thereof, and a method for catalyzing hydrogenation of aldehyde compounds, to provide a catalyst and a method with higher selectivity and conversion rate for hydrogenation of aldehyde compounds.

[0007] In order to achieve the above-mentioned purpose of the present application, the following technical solutions are adopted: The first aspect of the present application provides a hydrotalcite-supported trimetallic catalyst, comprising a CuAB-LDHs type hydrotalcite carrier and an active component supported on the CuAB-LDHs type hydrotalcite carrier; wherein the active component comprises metal elements Cu, A and B; the A and the B are inexpensive metal elements.

[0008] Further, the inexpensive metal elements comprise one of iron, cobalt, nickel, magnesium, aluminum and chromium.

[0009] Further, the copper content in the catalyst is 1-15 wt%.

[0010] Preferably, the molar ratio of the copper, the A and the B is 1:(1-50):1.

[0011] The second aspect of the present application provides a preparation method of the hydrotalcite-supported trimetallic catalyst, comprising the following steps: titrating an alkali solution into a mixed metal salt solution to perform co-precipitation to obtain a mixed solution, and then crystallizing, filtering, drying and reduction roasting the mixed solution to obtain the hydrotalcite-supported trimetallic catalyst; wherein the metals in the mixed metal salt solution comprise Cu, A and B.

[0012] Further, the alkali in the alkali solution comprises sodium hydroxide and sodium carbonate.

[0013] Preferably, the mixed metal salt solution comprises copper salt, metal A salt and metal B salt.

[0014] Preferably, the copper salt comprises at least one of copper nitrate, copper chloride and organic copper salt.

[0015] Preferably, the organic copper salt comprises copper acetate and / or copper oxalate.

[0016] Preferably, the metal A salt and the metal B salt are each independently at least one of nitrate, chloride or organic salt of iron, cobalt, nickel, magnesium, aluminum and chromium.

[0017] Further, the pH of the mixed solution is 9-11.

[0018] Preferably, the crystallization time is 8-24 h.

[0019] Preferably, the reduction roasting is performed in a reducing gas atmosphere.

[0020] Preferably, the reducing gas is selected from hydrogen or hydrogen-argon mixed gas.

[0021] Preferably, the hydrogen content in the hydrogen-argon mixed gas is 1-50 vol%.

[0022] Preferably, the temperature of the reduction is 400-800℃, and the time of the reduction is 1-5 h.

[0023] The third aspect of the present application provides the use of the hydrotalcite-supported trimetallic catalyst in catalyzing hydrogenation of aldehyde compounds.

[0024] The fourth aspect of the present application provides a method for catalyzing hydrogenation of aldehyde compounds, which comprises mixing the catalyst, the aldehyde compound and a solvent under a hydrogen atmosphere to obtain an alcohol compound. The catalyst is selected from the catalyst of the first aspect or the catalyst prepared according to the preparation method of the second aspect. The aldehyde compound is selected from at least one of furfural, benzaldehyde, 5-hydroxymethylfurfural, 5-methyl-2-furfuraldehyde, 4-chloro-2-furfuraldehyde, 5-ethyl-2-furfuraldehyde, 3-chloro-2-furfuraldehyde, 5-tert-butyl-2-furfuraldehyde, 5-(trifluoromethyl)-2-furfuraldehyde, 3-methylfurfural, 3-fluoro-2-furfuraldehyde and 4-ethyl-2-furfuraldehyde.

[0025] Further, the reaction is carried out in a high-pressure reaction kettle, and the reaction conditions are as follows: the reaction temperature is 80-130℃, the reaction time is 1-6 h, and the reaction pressure is 1-5 MPa.

[0026] Further, the mass ratio of the aldehyde compound to the catalyst is 1:(0.05-0.5).

[0027] Compared with the prior art, the present application has at least the following beneficial effects: The catalyst provided by the present application uniformly anchors the active component in the form of atomic dispersion or nanoparticles on the hydrotalcite (LDH) carrier with a layered structure, which not only fully utilizes the advantages of high specific surface area, rich surface hydroxyl groups and strong metal-support interaction of hydrotalcite, but also realizes the synergistic catalytic effect among the three metals. The catalyst structure significantly improves the exposure degree of active sites and the electronic transmission capacity of the catalyst, and enhances the adsorption and activation efficiency of reactant molecules on the catalyst surface.

[0028] The preparation method provided by the application is characterized in that metal ions not only participate in the construction of the layered main structure of the hydrotalcite (LDH), but also are converted into highly dispersed three-metal active components in the subsequent reduction process, realizing the integrated design of "structure-function". This dual-action mechanism makes the active metal species and the hydrotalcite carrier have stronger interaction force, effectively inhibits the migration and sintering of metal particles in the reaction process, and significantly improves the thermal stability and cycle durability of the catalyst; at the same time, since the active metal is derived from the uniformly distributed ions in the LDH skeleton, the dispersion degree of the active metal on the carrier is high, the particle size is small, and the composition is controllable, which is beneficial to expose more accessible active sites and enhance the catalytic activity. The preparation method avoids the problems of uneven loading and easy falling off of the active components in the traditional impregnation method, realizes the in-situ anchoring and efficient utilization of the active components, and greatly improves the overall performance and practicability of the catalyst.

[0029] The application provided by the application is characterized in that the active components in the catalyst are highly dispersed on the hydrotalcite carrier and have a synergistic effect, which can effectively activate H2 molecules and promote their dissociation and transfer in the reaction system, and at the same time, the adsorption configuration of the C=O bond in the aldehyde compound molecule is optimized, the carbonyl hydrogenation is preferentially catalyzed, and the side reactions such as furan ring hydrogenation or excessive hydrogenation are inhibited, so as to realize the high selectivity of furfuryl alcohol. The basic sites provided by the hydrotalcite carrier and its derived structure can also synergistically promote the stability and conversion of the reaction intermediates, further improving the reaction efficiency. In addition, the strong interaction between the metal and the carrier in the catalyst significantly enhances the anti-carbon deposition capacity and cycle stability, and can still maintain a high conversion rate and product yield in continuous reaction.

[0030] The aldehyde compound hydrogenation method provided by the application has the advantages of the above-mentioned application, so that the aldehyde compound hydrogenation method can be operated under relatively mild reaction conditions, has the advantages of low energy consumption, environmental friendliness, easy separation and reuse, and is suitable for green and efficient synthesis of furfuryl alcohol, and has good industrial application prospect. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the following specific embodiments or prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creating any inventive labor.

[0032] Figure 1 is the powder X-ray diffraction spectrum of the CuMg3Al1 catalyst prepared in Example 1.

[0033] Figure 2 is the N2O-TPR of the catalyst CuMg3Al1 prepared in Example 1.

[0034] Figure 3 Transmission electron microscope images of catalyst CuMg3Al1 prepared for example 1 at different angles.

[0035] Figure 4 Cycle number test chart of catalyst CuMg3Al1 prepared for example 1 for furfural hydrodeoxygenation to prepare furfuryl alcohol.

[0036] Figure 5 CuMg3Al1 prepared for example 1 is a furfural hydrodeoxygenation performance chart. DETAILED DESCRIPTION

[0037] In order to make the objects, technical solutions and advantages of the present application clearer, the following will combine the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments.

[0038] Hereinafter, the terms “include”, “have”, and their conjugations, which can be used in various embodiments of the present application, are only intended to denote that specific features, numbers, steps, operations, elements, components, or combinations thereof are present or are added, and should not be understood as excluding the existence or possibility of one or more other features, numbers, steps, operations, elements, components, or combinations thereof in advance.

[0039] The first aspect of the present application provides a water-sliding-layers supported trimetallic catalyst, comprising a CuAB-LDHs type water-sliding-layers carrier and an active component supported on the CuAB-LDHs type water-sliding-layers carrier; wherein the active component comprises metal elements Cu, A and B; the A and the B are inexpensive metal elements.

[0040] The catalyst provided by the present application uniformly anchors the active component in the form of atomic dispersion or nanoparticles on the water-sliding-layers (LDH) carrier with a layered structure, not only fully plays the advantages of high specific surface area, rich surface hydroxyl groups and strong metal-support interaction of water-sliding-layers, but also realizes the synergistic catalytic effect among the three metals. The catalyst structure significantly improves the exposure degree of active sites and the electronic transmission capacity of the catalyst, and enhances the adsorption and activation efficiency of reactant molecules on the catalyst surface.

[0041] Further, the inexpensive metal elements include one of iron, cobalt, nickel, magnesium, aluminum and chromium.

[0042] First, inexpensive metal elements not only participate in the construction of the layered main structure of hydrotalcite (LDH), providing high specific surface area and abundant surface hydroxyl groups to enhance metal-support interactions, but also achieve highly uniform dispersion with copper species through co-precipitation, thus forming small-particle-size, highly stable ternary metal active centers after reduction. Second, these inexpensive metals can regulate the acid-base properties of the support: for example, the combination of magnesium and nickel can form basic sites, promoting the stability and transformation of reaction intermediates; while the introduction of metals such as iron, cobalt, aluminum, or chromium may introduce appropriate acidic or redox sites, synergistically with the hydrogenation function of copper, optimizing the adsorption and activation of C=O bonds in aldehyde molecules, inhibiting side reactions (such as furan ring hydrogenation or excessive hydrogenation), and significantly improving the selectivity of target alcohols. All of the above inexpensive metals can effectively construct high-performance catalytic systems, ensuring high activity while reducing costs and avoiding the environmental problems caused by toxic elements (such as hexavalent chromium in traditional Cr-based catalysts), demonstrating excellent economic efficiency, versatility, and green sustainability advantages.

[0043] Furthermore, the copper content in the catalyst is 1~15wt%.

[0044] Typically, but not limitingly, the copper content in the catalyst can be, for example, 1 wt%, 3 wt%, 5 wt%, 7 wt%, 9 wt%, 11 wt%, 13 wt%, or 15 wt%, or any value in the range of 1 to 15 wt%.

[0045] Preferably, the molar ratio of copper, A and B is 1:(1~50):1.

[0046] Typically, but not limitingly, the molar ratio of copper, A, and B can be, for example, 1:1:1, 1:5:1, 1:10:1, 1:20:1, 1:30:1, 1:40:1, or 1:50:1, or any value within the range of 1:(1~50):1.

[0047] The second aspect of the present invention provides a method for preparing the hydrotalcite-supported trimetallic catalyst, wherein an alkaline solution is titrated into a mixed solution of metal salts for co-precipitation to obtain a mixed solution, and then the mixed solution is crystallized, filtered, dried, and reduced-calcined to obtain the hydrotalcite-supported trimetallic catalyst; wherein the metals in the mixed solution of metal salts include Cu, A, and B.

[0048] The preparation method provided by this invention allows metal ions to both participate in the construction of the layered main structure of hydrotalcite (LDH) and be transformed into highly dispersed trimetallic active components during the subsequent reduction process, achieving an integrated "structure-function" design. This dual-action mechanism strengthens the interaction between the active metal species and the LDH support, effectively inhibiting the migration and sintering of metal particles during the reaction process, and significantly improving the thermal stability and cycle durability of the catalyst. Simultaneously, since the active metals originate from uniformly distributed ions in the LDH framework, their high dispersion, small particle size, and controllable composition on the support facilitate the exposure of more accessible active sites, enhancing catalytic activity. This preparation method avoids the problems of uneven loading and easy detachment of active components in traditional impregnation methods, achieving in-situ anchoring and efficient utilization of active components, and significantly improving the overall performance and practicality of the catalyst.

[0049] Furthermore, the alkali in the alkaline solution includes sodium hydroxide and sodium carbonate.

[0050] Preferably, the metal salt mixture solution includes copper salt, metal A salt, and metal B salt.

[0051] Preferably, the copper salt includes at least one of copper nitrate, copper chloride, and organic copper salts.

[0052] Preferably, the organic copper salt comprises copper acetate and / or copper oxalate.

[0053] Preferably, the metal A salt and the metal B salt are each independently at least one of the following: nitrates, chlorides, or organic salts of iron, cobalt, nickel, magnesium, aluminum, and chromium.

[0054] Furthermore, the pH of the mixed solution is 9-11. Within this alkaline range, metal ions can co-precipitate with hydroxide and carbonate ions, promoting the directional growth of layered double hydroxide crystals, thereby forming a CuAB-LDHs precursor with a regular structure, high crystallinity, and large specific surface area. If the pH is too low (<9), metal ions are difficult to fully hydrolyze, easily generating amorphous precipitates or impurities, leading to uneven dispersion of active components. If the pH is too high (>11), some metals (such as aluminum) may dissolve to form aluminates, disrupting the charge balance of the layers and affecting the integrity and stability of the LDH structure. Therefore, maintaining the pH at 9-11 not only facilitates the atomic-level uniform distribution of various metal ions in the support, laying the foundation for obtaining highly dispersed, small-particle-size trimetallic active centers in subsequent reduction, but also enhances the interaction between the metal and the support, improves the thermal stability and anti-sintering ability of the catalyst, and ultimately achieves high catalytic activity and long cycle life.

[0055] Typically, but not limitingly, the pH of the mixed solution can be, for example, 9.0, 9.5, 10.0, 10.5 or 11.0, or any value in the range of 9 to 11.

[0056] Preferably, the crystallization time is 8 to 24 hours.

[0057] Typically, but not limitingly, the crystallization time can be, for example, 8 h, 10 h, 12 h, 14 h, 16 h, 18 h, 20 h, 22 h or 24 h, or any value in the range of 8 to 24 h.

[0058] Preferably, the reduction calcination is carried out in a reducing gas atmosphere.

[0059] Preferably, the reducing gas is selected from hydrogen or a hydrogen-argon mixture.

[0060] Preferably, the hydrogen content in the hydrogen-argon mixture is 1-50 vol.

[0061] Typically, but not limitingly, the hydrogen content in the hydrogen-argon mixture can be, for example, 1 vol%, 5 vol%, 10 vol%, 15 vol%, 20 vol%, 25 vol%, 30 vol%, 35 vol%, 40 vol%, 45 vol%, or 50 vol%, or any value in the range of 1 to 50 vol%.

[0062] Preferably, the reduction temperature is 400~800℃, and the reduction time is 1~5 h.

[0063] Typically, but not limitingly, the reduction temperature can be, for example, 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C, or 800°C, or any value within the range of 400°C to 800°C; the reduction time can be, for example, 1 h, 2 h, 3 h, 4 h, or 5 h, or any value within the range of 1 to 5 h.

[0064] The third aspect of this invention provides the application of the hydrotalcite-supported trimetallic catalyst in the catalytic hydrogenation of aldehyde compounds.

[0065] The application provided by this invention, given the high dispersion and synergistic effect of the active components in the catalyst on the hydrotalcite support, effectively activates H2 molecules and promotes their dissociation and transfer in the reaction system. Simultaneously, it optimizes the adsorption configuration of C=O bonds in aldehyde compounds, preferentially catalyzing carbonyl hydrogenation while suppressing side reactions such as furan ring hydrogenation or excessive hydrogenation, thereby achieving highly selective production of furfuryl alcohol. The basic sites provided by the hydrotalcite support and its derived structures can also synergistically promote the stability and transformation of reaction intermediates, further improving reaction efficiency. Furthermore, the strong interaction between the metal and the support in the catalyst significantly enhances its resistance to carbon deposition and cycling stability, maintaining high conversion and product yield even in continuous reactions.

[0066] The fourth aspect of this invention provides a method for catalytic hydrogenation of aldehyde compounds, wherein a catalyst, an aldehyde compound, and a solvent are mixed and reacted under a hydrogen atmosphere to obtain an alcohol compound; The catalyst is selected from the catalyst described in the first aspect or the catalyst prepared according to the preparation method described in the second aspect.

[0067] The aldehyde compound is selected from at least one of furfural, benzaldehyde, 5-hydroxymethylfurfural, 5-methyl-2-furanaldehyde, 4-chloro-2-furanaldehyde, 5-ethyl-2-furanaldehyde, 3-chloro-2-furanaldehyde, 5-tert-butyl-2-furanaldehyde, 5-(trifluoromethyl)-2-furanaldehyde, 3-methylfurfural, 3-fluoro-2-furanaldehyde, and 4-ethyl-2-furanmethylamine.

[0068] The method for hydrogenating aldehydes provided by this invention, given the advantages of the above-mentioned applications, allows the hydrogenation of aldehydes to operate under relatively mild reaction conditions, and has advantages such as low energy consumption, environmental friendliness, easy separation and reuse. It is suitable for the green and efficient synthesis of furfuryl alcohol and has good prospects for industrial application.

[0069] Furthermore, the reaction is carried out in a high-pressure reactor under the following conditions: reaction temperature 80~130℃, reaction time 1~6 h, and reaction pressure 1~5 MPa.

[0070] Typically, but not limitingly, the reaction is carried out in a high-pressure reactor, and the reaction conditions are as follows: the reaction temperature can be, for example, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, or 130 °C, or any value within the range of 80 to 130 °C; the reaction time can be, for example, 1 h, 2 h, 3 h, 4 h, 5 h, or 6 h, or any value within the range of 1 to 6 h; the reaction pressure can be, for example, 1 MPa, 2 MPa, 3 MPa, 4 MPa, or 5 MPa, or any value within the range of 1 to 5 MPa.

[0071] Furthermore, the mass ratio of the aldehyde compound to the catalyst is 1:(0.05-0.5).

[0072] Typically, but not limitingly, the mass ratio of the aldehyde compound to the catalyst can be, for example, 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45 or 1:0.5, or any value in the range of 1:(0.05~0.5).

[0073] The present invention is further illustrated below with specific embodiments and comparative examples. However, it should be understood that these embodiments are merely for illustrative purposes and should not be construed as limiting the invention in any way. Unless otherwise specified, the raw materials used in the embodiments and comparative examples of the present invention were carried out under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0074] Example 1 This embodiment provides a catalyst prepared by the following steps: 1. Disperse 189 mg of copper salt in 200 mL of water, and then add 40 mL of aqueous solution containing 4.567 g of magnesium salt and 1.75 g of aluminum salt while stirring to obtain a mixed solution of metal salts.

[0075] 2. Slowly add an alkaline solution containing sodium hydroxide and sodium carbonate to a mixed solution of metal salts while stirring continuously to crystallize. Then, centrifuge the solid and dry it in a 100°C oven for 24 hours to obtain a solid phase.

[0076] 3. The solid material was placed in a ceramic boat and placed in a tube furnace. The heating rate was set to 3°C / min, and the temperature was raised to 450°C. The solid material was calcined for 2 h in an atmosphere of hydrogen-argon mixture with 5 vol% hydrogen. Then it was naturally cooled to room temperature and the gas was turned off to obtain CuMg3Al1-LDHs solid powder with a copper metal loading of 5 wt%.

[0077] The catalyst prepared above was characterized as follows: Figure 1 The image shows the powder X-ray diffraction pattern of the 5% CuMg3Al1 catalyst prepared in Example 1. Comparison with the standard card indicates that the catalyst with the CuMgAl hydrotalcite structure was successfully synthesized.

[0078] Figure 2 The image shows a transmission electron microscope image of the 5% CuMg3Al1 catalyst, indicating that the Cu NPs are uniformly dispersed and of uniform size.

[0079] Figure 3Transmission electron microscope images of the catalyst CuMg3Al1 prepared in Example 1 from different angles.

[0080] Example 2 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 94.5 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 2.5 wt% CuMg3Al1 catalyst is prepared.

[0081] Example 3 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 283.5 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 7.5 wt% CuMg3Al1 catalyst is prepared.

[0082] Example 4 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 378 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 10 wt% CuMg3Al1 catalyst is prepared.

[0083] Example 5 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 472.5 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 12.5 wt% CuMg3Al1 catalyst is prepared.

[0084] Example 6 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 567 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 15 wt% CuMg3Al1 catalyst is prepared.

[0085] Example 7 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 661.5 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 17.5 wt% CuMg3Al1 catalyst is prepared.

[0086] Example 8 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 756 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 20 wt% CuMg3Al1 catalyst is prepared.

[0087] Example 9 This embodiment provides a catalyst, which differs from Example 1 only in that the amount of copper salt used is 945 mg. The remaining preparation steps and material selection are the same as in Example 1, and a 25 wt% CuMg3Al1 catalyst is prepared.

[0088] Test Example 1: Investigation of the effect of copper salt dosage on catalyst activity Test samples: Catalysts provided in Examples 1-9; Test method: 87 mg of catalyst and 10 mmol of furfural were dissolved in 30 mL of methanol solution and added to a high-pressure reactor. Hydrogen gas at 2 MPa was introduced, the temperature was raised to 110 °C, the rotation speed was set to 800 rpm, and the reaction was carried out for 2 h. 50 μL of the reaction solution was taken and the yield of furfural was detected by gas chromatography.

[0089] The test results are shown in Table 1 below: Table 1

[0090] As shown in Table 1, the catalyst activity increases significantly with the increase of copper salt content. When the copper salt content increases to over 5%, the yield of furfuryl alcohol exceeds 95%. When the copper salt content is further increased to 17.5%, the yield of furfuryl alcohol exceeds 99%, indicating that the increase of copper salt content increases the number of catalytically active sites, which is beneficial to promoting the catalytic hydrogenation of furfural to furfuryl alcohol. Therefore, the co-precipitation method for synthesizing copper-based catalysts provided by this invention can effectively improve the catalytic efficiency of the furfural hydrogenation deoxygenation reaction.

[0091] Furthermore, 87 mg of the CuMg3Al1 catalyst prepared in Example 1 was cycled 5 times using the above-described method for selectively catalyzing furfural, with each reaction lasting 2.5 h. The conversion rate and selectivity of furfuryl alcohol were measured for each reaction, and the results are as follows: Figure 4 As shown, the catalyst did not exhibit significant deactivation in 5 cycle tests, further confirming its high stability. Figure 4 The catalyst provided by this invention can maintain at least 5 cycles of 2.5 hours per reaction, demonstrating significant stability. This is because the CuMg3Al1 catalyst prepared by the co-precipitation method is a hydrotalcite-like catalyst with a layered structure, high crystallinity, and large specific surface area. The catalyst of this invention can selectively hydrogenate furfural to furfuryl alcohol, with a furfuryl alcohol yield >99%, exhibiting excellent catalytic activity and selectivity.

[0092] Example 10 This embodiment provides a catalyst, which differs from Example 1 only in that the ratio of magnesium salt and aluminum salt is adjusted to 1:1. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg1Al1 catalyst is prepared.

[0093] Example 11 This embodiment provides a catalyst, differing from Example 1 only in that the ratio of magnesium salt and aluminum salt is adjusted to 1.5:1. The remaining preparation steps and material selection are the same as in Example 1, yielding a 5 wt% CuMg catalyst. 1.5 Al1 catalyst.

[0094] Example 12 This embodiment provides a catalyst, which differs from Example 1 only in that the ratio of magnesium salt and aluminum salt is adjusted to 2:1. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg2Al1 catalyst is prepared.

[0095] Example 13 This embodiment provides a catalyst, differing from Example 1 only in that the ratio of magnesium salt and aluminum salt is adjusted to 2.5:1. The remaining preparation steps and material selection are the same as in Example 1, yielding a 5 wt% CuMg catalyst. 2.5 Al1 catalyst.

[0096] Example 14 This embodiment provides a catalyst, which differs from Example 1 only in that the ratio of magnesium salt and aluminum salt is adjusted to 4:1. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg4Al1 catalyst is prepared.

[0097] Example 15 This embodiment provides a catalyst, which differs from Example 1 only in that the ratio of magnesium salt and aluminum salt is adjusted to 5:1. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg5Al1 catalyst is prepared.

[0098] Test Example 2: Investigation of the catalytic activity of the catalyst by the metal precursor Test samples: the catalyst provided in Example 1, and the catalysts provided in Examples 10-15; Test method: Same as test example 1.

[0099] The test results are shown in Table 2 below: Table 2

[0100] As shown in Table 2, the yield of furfuryl alcohol first increases and then decreases with the increase of the Mg:Al mass ratio, indicating that appropriately increasing the proportion of Mg can provide basic sites for the catalyst, which is beneficial to improving catalytic activity. Therefore, the co-precipitation method provided by this invention to control the Mg:Al ratio can effectively improve the catalytic efficiency of the catalyst in the hydrogenation of furfural to furfuryl alcohol.

[0101] Example 16 This embodiment provides a catalyst, which differs from Example 1 only in that the aluminum metal salt is replaced with an equal mass of iron metal salt, the reducing atmosphere is hydrogen, and the reducing temperature is 450°C. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Fe1 catalyst is prepared.

[0102] Example 17 This embodiment provides a catalyst, which differs from Example 1 only in that the aluminum metal salt is replaced with an equal mass of cobalt metal salt, the reducing atmosphere is hydrogen, and the reducing temperature is 450°C. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Co1 catalyst is prepared.

[0103] Example 18 This embodiment provides a catalyst, which differs from Example 1 only in that the aluminum metal salt is replaced with an equal mass of nickel metal salt, the reducing atmosphere is hydrogen, and the reducing temperature is 450°C. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Ni1 catalyst is prepared.

[0104] Example 19 This embodiment provides a catalyst, which differs from Example 1 only in that the aluminum metal salt is replaced with an equal mass of the chromium metal salt, the reducing atmosphere is hydrogen, and the reducing temperature is 550°C. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Cr1 catalyst is prepared.

[0105] Test Example 3: Investigation of the effect of different metal complexes on the catalytic activity of catalysts Test samples: the catalyst provided in Example 1, and the catalysts provided in Examples 16-19; Test method: Same as test example 1.

[0106] The test results are shown in Table 3 below: Table 3

[0107] As shown in Table 3, the CuAB-LDHs catalysts obtained by the co-precipitation method using different metal salts B all achieved good results, with furfuryl alcohol yields all exceeding 95%. Therefore, the co-precipitation method for synthesizing copper-based catalysts provided by this invention is applicable to metal salt solutions of various copper-based catalysts, effectively improving the catalytic efficiency of the catalytic hydrogenation of furfural to furfuryl alcohol using copper-based catalysts.

[0108] Example 20 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 400℃, while the remaining preparation steps and material selection are the same as in Example 1, resulting in the preparation of a 5 wt% CuMg3Al1-400 catalyst.

[0109] Example 21 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 500℃, while the remaining preparation steps and material selection are the same as in Example 1, resulting in the preparation of a 5 wt% CuMg3Al1-500 catalyst.

[0110] Example 22 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 550°C. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-550 catalyst is prepared.

[0111] Example 23 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 600℃, while the remaining preparation steps and material selection are the same as in Example 1, resulting in the preparation of a 5 wt% CuMg3Al1-600 catalyst.

[0112] Example 24 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 650°C. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-650 catalyst is prepared.

[0113] Example 25 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 700℃, while the remaining preparation steps and material selection are the same as in Example 1, resulting in the preparation of a 5 wt% CuMg3Al1-700 catalyst.

[0114] Example 26 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination temperature in this embodiment is 800℃, while the remaining preparation steps and material selection are the same as in Example 1, resulting in the preparation of a 5 wt% CuMg3Al1-800 catalyst.

[0115] Test Example 4: Investigation of the effect of different calcination temperatures on the catalytic activity of the catalyst Test samples: the catalyst provided in Example 1, and the catalysts provided in Examples 20-26; Test method: Same as test example 1.

[0116] The test results are shown in Table 4 below: Table 4

[0117] As can be seen from Table 4, when the calcination temperature is increased from 400℃ to 800℃, the activity of the copper-based catalyst in the catalytic hydrogenation of furfural is significantly improved, and the yield of furfuryl alcohol reaches about 95%.

[0118] Example 27 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination time in this embodiment is 1 h, while the remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-1 h catalyst is prepared.

[0119] Example 28 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination time in this embodiment is 1.5 h. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-1.5 h catalyst is prepared.

[0120] Example 29 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination time in this embodiment is 2.5 h. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-2.5 h catalyst is prepared.

[0121] Example 30 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination time in this embodiment is 3 h. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-3 h catalyst is prepared.

[0122] Example 31 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination time in this embodiment is 4 h. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-4 h catalyst is prepared.

[0123] Example 32 This embodiment provides a catalyst, which differs from Example 1 only in that the calcination time in this embodiment is 5 h. The remaining preparation steps and material selection are the same as in Example 1, and a 5 wt% CuMg3Al1-5 h catalyst is prepared.

[0124] Test Example 5: Investigation of the effect of different modification times on the catalytic activity of the catalyst Test samples: the catalyst provided in Example 1, and the catalysts provided in Examples 27-32; Test method: Same as test example 1.

[0125] The test results are shown in Table 5 below: Table 5

[0126] As shown in Table 5, increasing the calcination time from 1 h to 5 h significantly improved the activity of the copper-based catalyst synthesized by the co-precipitation method for the catalytic hydrogenation of furfural. In particular, the yield of furfuryl alcohol reached about 95% when the calcination time was within 2-3 h. However, when the calcination time was further extended to 4 h and 5 h, the yield of furfuryl alcohol decreased significantly. This is because the long calcination time caused the copper nanoparticles to agglomerate, resulting in a reduction of active sites for catalytic hydrogenation and thus a slight decrease in activity.

[0127] Application Example 1 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol. The method includes the following steps: dissolving 87 mg of the catalyst provided in Example 1 and 10 mmol of benzaldehyde in 30 mL of methanol solution, adding the solution to a high-pressure reactor, introducing 2 MPa of hydrogen gas, heating to 110 °C, setting the rotation speed to 800 rpm, and reacting for 2.5 h. Then, taking 50 μL of the reaction solution and detecting the yield of benzyl alcohol by gas chromatography.

[0128] Application Example 2 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 5-hydroxymethylfurfural, the reaction time is 2.5 h, and the yield of the product 5-hydroxymethylfurfural is detected by gas chromatography.

[0129] Application Example 3 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 5-methyl-2-furanaldehyde, the reaction time is 5 h, and the yield of the product 5-methyl-2-furanmethanol is detected by gas chromatography.

[0130] Application Example 4 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 4-chloro-2-furanaldehyde, the reaction time is 3 h, and the yield of the product 4-chloro-2-furanmethanol is detected by gas chromatography.

[0131] Application Example 5 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 5-ethyl-2-furan carbaldehyde, the reaction time is 3 h, and the yield of the product 5-ethyl-2-furan methanol is detected by gas chromatography.

[0132] Application Example 6 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 3-chloro-2-furanaldehyde, the reaction time is 2 h, and the yield of the product 3-chloro-2-furanmethanol is detected by gas chromatography.

[0133] Application Example 7 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 5-tert-butyl-2-furan carbaldehyde, the reaction time is 2 h, and the yield of the product 5-tert-butyl-2-furan methanol is detected by gas chromatography.

[0134] Application Example 8 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol. The only difference from Application Example 1 is that benzaldehyde is replaced with 5-(trifluoromethyl)-2-furan carbaldehyde, the reaction time is 4 h, and the yield of the product 5-(trifluoromethyl)-2-furan methanol is detected by gas chromatography.

[0135] Application Example 9 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 3-methylfurfural, the reaction time is 2 h, and the yield of the product 3-methylfurfural is detected by gas chromatography.

[0136] Application Example 10 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with 3-fluoro-2-furanaldehyde, the reaction time is 2.5 h, and the yield of the product 3-fluoro-2-furan methanol is detected by gas chromatography.

[0137] Application Example 11 This application example provides a method for the catalytic hydrogenation of aldehyde compounds to prepare furfuryl alcohol, which differs from Application Example 1 only in that benzaldehyde is replaced with p-4-ethyl-2-furan carbaldehyde, the reaction time is 5 h, and the yield of the product 4-ethyl-2-furan methanol is detected by gas chromatography.

[0138] Test Example 6: Investigation of Hydrogenated Substrates Test sample: Use the reaction solution provided in Examples 1-11; The test results are shown in Table 6 below: Table 6

[0139] As can be seen from Table 6, the CuMg3Al1 catalyst synthesized by the coprecipitation method has excellent catalytic hydrogenation performance for different aldehyde substrates, and the yield of the corresponding products reaches about 95%.

[0140] More specifically, by tracking the product yield curves of the catalytic hydrogenation of 5-hydroxymethylfurfural to 5-hydroxymethylfurfural before and after modification of the CuMg3Al1 catalyst, it can be seen that the unmodified CuMg3Al1 catalyst exhibits poor activity in the catalytic hydrogenation of 5-hydroxymethylfurfural and is also poisoned. This is because the product alcohol has a strong interaction with metallic copper, which adsorbs on the surface and blocks the active sites, thus poisoning the catalyst. In contrast, the modified CuMg3Al1 catalyst, by introducing aluminum salts, forms a certain number of acidic sites on its surface. Under the synergistic catalysis of metallic copper sites, acidic sites, and basic sites, the catalytic hydrogenation performance is significantly improved. At the same time, the layered structure design ensures that the catalyst is not poisoned during the hydrogenation process, ensuring that the target product is obtained with a yield of 96.1% of 5-hydroxymethylfurfural after 2.5 hours of reaction. Figure 5 ).

[0141] Therefore, the co-precipitation method for synthesizing copper-based catalysts provided by this invention is not only applicable to the modification of various copper-based catalysts, but also to the catalytic hydrogenation of aldehyde-based substrates with different functional groups. It has broad substrate applicability and can effectively improve the catalytic efficiency of copper-based catalysts in the catalytic hydrogenation reaction of aldehyde compounds.

[0142] Finally, it should be noted that the above-described embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A hydrotalcite-supported trimetallic catalyst, characterized in that, Includes CuAB-LDHs type hydrotalcite carrier and active components loaded on the CuAB-LDHs type hydrotalcite carrier; The active components include the metal elements Cu, A, and B; A and B are inexpensive metal elements.

2. The hydrotalcite-supported trimetallic catalyst according to claim 1, characterized in that, The inexpensive metal elements include one of the following: iron, cobalt, nickel, magnesium, aluminum, and chromium.

3. The hydrotalcite-supported trimetallic catalyst according to claim 1, characterized in that, The catalyst contains 1-15 wt% copper. Preferably, the molar ratio of copper, A and B is 1:(1~50):

1.

4. A method for preparing a hydrotalcite-supported trimetallic catalyst according to any one of claims 1 to 3, characterized in that, An alkaline solution was titrated into a mixed solution of metal salts to co-precipitate and obtain a mixed solution. The mixed solution was then crystallized, filtered, dried, and reduced-calcined to obtain the hydrotalcite-supported trimetallic catalyst. The metals in the metal salt mixture solution include Cu, A, and B.

5. The preparation method according to claim 4, characterized in that, The alkali in the alkaline solution includes sodium hydroxide and sodium carbonate; Preferably, the metal salt mixed solution includes copper salt, metal A salt, and metal B salt; Preferably, the copper salt includes at least one of copper nitrate, copper chloride, and organic copper salts; Preferably, the organic copper salt comprises copper acetate and / or copper oxalate; Preferably, the metal A salt and the metal B salt are each independently at least one of the following: nitrates, chlorides, or organic salts of iron, cobalt, nickel, magnesium, aluminum, and chromium.

6. The preparation method according to claim 4, characterized in that, The pH of the mixed solution is 9-11; Preferably, the crystallization time is 8~24 hours; Preferably, the reduction calcination is carried out in a reducing gas atmosphere; Preferably, the reducing gas is selected from hydrogen or a hydrogen-argon mixture; Preferably, the hydrogen content in the hydrogen-argon mixture is 1-50 vol%. Preferably, the reduction temperature is 400~800℃, and the reduction time is 1~5 h.

7. The application of a hydrotalcite-supported trimetallic catalyst according to any one of claims 1 to 3 in the catalytic hydrogenation of aldehyde compounds.

8. A method for catalytic hydrogenation of aldehyde compounds, characterized in that, The catalyst, aldehyde compound, and solvent are mixed and reacted under a hydrogen atmosphere to obtain alcohol compound; The catalyst is selected from the catalyst according to any one of claims 1 to 3 or the catalyst prepared according to the preparation method according to any one of claims 4 to 6; The aldehyde compound is selected from at least one of furfural, benzaldehyde, 5-hydroxymethylfurfural, 5-methyl-2-furanaldehyde, 4-chloro-2-furanaldehyde, 5-ethyl-2-furanaldehyde, 3-chloro-2-furanaldehyde, 5-tert-butyl-2-furanaldehyde, 5-(trifluoromethyl)-2-furanaldehyde, 3-methylfurfural, 3-fluoro-2-furanaldehyde, and 4-ethyl-2-furanmethylamine.

9. The method according to claim 8, characterized in that, The reaction is carried out in a high-pressure reactor under the following conditions: reaction temperature 80~130℃, reaction time 1~6 h, and reaction pressure 1~5 MPa.

10. The method according to claim 8, characterized in that, The mass ratio of the aldehyde compound to the catalyst is 1:(0.05-0.5).

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