A supported nanocubic nickel-gallium alloy catalyst for the selective hydrogenation of alpha, beta-unsaturated aldehydes and ketones to saturated aldehydes and ketones

Abstract

The application discloses a supported nanocubic nickel-gallium alloy catalyst, a preparation method thereof and a method for preparing saturated aldehyde / ketone by selectively hydrogenating alpha, beta-unsaturated aldehyde / ketone. The catalyst comprises a nitrogen-doped porous carbon material as a carrier and metal nickel-gallium alloy nanocubic particles as an active component, the size of the nanocubic structure is 5-100 nm, the content of nickel is 0.1wt%-10wt% and the content of gallium is 0.1wt%-8wt% based on the total weight of the catalyst, and the molar ratio of gallium to nickel is 0.01:1-3:1. The catalyst has a regular nanocubic structure and a core-shell structure with the metal nickel-gallium alloy nanocubic particles as the core and the nitrogen-doped porous carbon material as the shell. The catalyst can be used for catalyzing the selective hydrogenation of various alpha, beta-unsaturated aldehyde / ketone to prepare saturated aldehyde / ketone, and exhibits excellent catalytic activity, chemical selectivity, stereoselectivity and cycle stability.

Description

Technical fields:

[0001] This application belongs to the field of selective hydrogenation catalyst technology, specifically relating to a supported nano-cubic nickel-gallium alloy catalyst, its preparation method, and its method for catalyzing the selective hydrogenation of α,β-unsaturated aldehydes / ketones to prepare saturated aldehydes / ketones. Background technology:

[0002] Selective hydrogenation of α,β-unsaturated aldehydes / ketones is an important industrial production process with significant applications in fine chemical products such as chemicals, pharmaceuticals, food, fragrances, resins, and pesticides. Thermodynamically, the bond energy of the C=O bond is 715 kJ / mol, while that of the C=C bond is 615 kJ / mol. Compared to the C=O bond, the C=C bond is more prone to hydrogenation reactions. However, because the C=C and C=O bonds in α,β-unsaturated aldehydes / ketones form a conjugated system, obtaining specific unsaturated alcohols or saturated aldehydes / ketones through selective hydrogenation is quite difficult. Regardless of whether it is C=C or C=O hydrogenation, researchers are committed to selectively hydrogenating to generate a single product to achieve controllable preparation of the target product, improve atom utilization, and align with the current research concepts of green chemistry. This has always been one of the challenging reactions in the field of catalysis.

[0003] Among various α,β-unsaturated aldehydes / ketones, cinnamaldehyde (CAL) is a representative model reactant. Its C=O hydrogenation product, cinnamic alcohol (COL), and C=C hydrogenation product, hydrocinnamaldehyde (HCAL), are also used in various fields. COL is reportedly often used as a fixative and modifier, and has wide applications in the biopharmaceutical field. HCAL, another product, can be used as an intermediate reagent in the synthesis of antiviral drugs, especially HIV protease inhibitors. Currently, the main route for synthesizing HCAL is the toluene chlorination hydrolysis method. Although the yield is high, the waste liquid (acidic) is difficult to treat, and the generated HCl easily corrodes equipment. However, using hydrogen as a reducing agent, the selective hydrogenation of CAL to HCAL does not produce any corrosive byproducts or waste. Furthermore, this method also suffers from relatively high catalyst preparation costs, complex synthetic routes, and high reaction temperatures (T>150℃).

[0004] To address the problems existing in the above-mentioned technologies, the development of novel, highly active, and highly selective α,β-unsaturated aldehyde / ketone selective hydrogenation catalysts has significant theoretical importance and broad prospects for industrial application. Summary of the Invention:

[0005] To address the shortcomings of the existing technology, one objective of this application is to provide a supported nanocubic nickel-gallium alloy catalyst. The supported nanocubic nickel-gallium alloy catalyst has a core-shell structure, wherein a nitrogen-doped porous carbon material serving as a support coats the nickel-gallium alloy as the active component. The catalyst possesses a regular nanocubic structure, enabling it to selectively perform C=C bond hydrogenation in catalyzing various α,β-unsaturated aldehyde / ketone reactions, thereby preparing saturated aldehydes / ketones. Furthermore, the catalyst can reduce reaction temperature, pressure, and time, thereby reducing investment costs and energy consumption. Simultaneously, it uses water as a solvent, making it environmentally friendly and pollution-free, minimizing adverse environmental impacts. Moreover, the catalyst exhibits good cycle stability, allowing for repeated use; after six cycles, it still maintains good activity and selectivity.

[0006] Another objective of this application is to provide a method for preparing the above-mentioned supported nano-cubic nickel-gallium catalyst. The method uses inexpensive, renewable biomass as the raw material for preparing the carbon precursor, making it green, environmentally friendly, and convenient. Furthermore, the nano-cubic nickel-gallium alloy catalyst with a carbon layer can be synthesized in situ through secondary calcination and carbothermic reduction.

[0007] Another objective of this application is to provide a method for preparing saturated aldehydes / ketones using the above-mentioned supported nanocubic nickel-gallium alloy catalyst. The method uses hydrogen as a reducing agent to improve atom utilization, and the special nanocubic structure of the catalyst alters the adsorption mode of α,β-unsaturated aldehyde / ketone molecules, enabling the controllable preparation of saturated aldehyde / ketone products.

[0008] To achieve the above objectives, in a first aspect, this application provides a supported nanocubic nickel-gallium alloy catalyst, comprising a nitrogen-doped porous carbon material as a support and metallic nickel-gallium alloy nanocubic particles as an active component. The catalyst has a regular nanocubic structure and a core-shell structure with the metallic nickel-gallium alloy nanocubic particles as the core and the nitrogen-doped porous carbon material as the shell. The size of the nanocubic structure is 5 to 100 nm. Based on the total weight of the catalyst, the nickel content is 0.1 wt% to 10 wt%, and the gallium content is 0.1 wt% to 8 wt%. The molar ratio of gallium to nickel is 0.01:1 to 3:1, preferably 0.25:1 to 3:1, and more preferably 1:1.

[0009] Preferably, the size of the nanocubic structure is 10 to 50 nm.

[0010] Preferably, the nickel content is 2 wt% to 8 wt%, and more preferably, the nickel content in the supported nano-cubic nickel-gallium alloy catalyst is 4 wt% to 7 wt%.

[0011] Preferably, the gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 2 wt% to 6 wt%, and more preferably, the gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 3 wt% to 5 wt%. In conjunction with the first aspect, in a feasible embodiment, the nitrogen-doped porous carbon material has a density of 50 μm. 2 / g~1000m 2 The specific surface area is 1 / g and the nitrogen content is 1wt% to 20wt%. Preferably, the nitrogen-doped porous carbon material has a specific surface area of ​​100m² / g and a nitrogen content of 1wt% to 20wt%. 2 / g~500m 2 Specific surface area per g and nitrogen content of 1wt% to 10wt%.

[0012] Secondly, this application provides a method for preparing the above-mentioned supported nano-cubic nickel-gallium alloy catalyst, which includes the following steps:

[0013] (1) Peel and wash fresh bamboo shoots, slice them, dry them and grind them into powder. Mix them with water and carry out a hydrothermal reaction at 100-230°C, preferably 180°C, for 2-10 hours, preferably 4-6 hours. Then filter, wash and dry to obtain nitrogen-doped porous carbon material precursor.

[0014] (2) The nitrogen-doped porous carbon material precursor obtained in step (1) is impregnated with an aqueous solution of adsorbent nickel salt, dried, and ground to obtain adsorbent particles; and

[0015] (3) The adsorption particles obtained in step (2) are calcined in an inert atmosphere at a temperature of 500-1000°C, preferably 800°C, for 1-5 hours, preferably 2-3 hours, then cooled and ground to obtain a supported nickel-containing nanoparticle catalyst.

[0016] (4) The supported nickel-containing nanoparticle catalyst obtained in step (3) is impregnated with an aqueous solution of gallium salt, dried, and ground to obtain adsorbed particles; and

[0017] (5) The adsorption particles obtained in step (4) are calcined for 1 to 5 hours, preferably 2 to 3 hours, at 500 to 1000°C, preferably 800°C, in an inert atmosphere to reconstruct the structure in situ and generate a nano cubic structure. The particles are then cooled and ground to obtain the supported nano cubic nickel-gallium alloy catalyst.

[0018] In conjunction with step (1) of the second aspect, the bamboo shoots are seedlings of the plant Bambusoideae, aged 0 to 3 months.

[0019] In conjunction with step (2) of the second aspect, the immersion temperature is 40-80°C, preferably 60°C; the immersion time is 1-4 hours, preferably 2 hours.

[0020] In conjunction with step (2) of the second aspect, the concentration of nickel in the nickel salt aqueous solution is 0.004 to 0.04 mol / L, preferably 0.01 mol / L.

[0021] In conjunction with step (2) of the second aspect, the nickel salt in the nickel salt aqueous solution can be at least one selected from nickel acetate hydrate, nickel nitrate, nickel chloride, nickel carbonate and nickel sulfate, preferably nickel acetate hydrate.

[0022] In conjunction with step (2) of the second aspect, the weight ratio of the nitrogen-doped porous carbon material precursor to the nickel salt is 50:1 to 150:1, preferably 100:1.

[0023] In conjunction with step (4) of the second aspect, the immersion temperature is 80-120°C, preferably 100°C; the immersion time is 4-24 hours, preferably 12-18 hours.

[0024] In conjunction with step (4) of the second aspect, the concentration of gallium in the gallium salt aqueous solution is 0.004 to 0.04 mol / L, preferably 0.01 mol / L.

[0025] In conjunction with step (4) of the second aspect, the gallium salt in the gallium salt aqueous solution can be at least one selected from gallium nitrate hydrate, gallium chloride, gallium ethoxide, gallium isopropoxide, gallium acetylacetonate and gallium triethylidene, preferably gallium nitrate hydrate.

[0026] In conjunction with step (4) of the second aspect, the molar ratio of the gallium salt to the nickel salt in step (2) is 0.01:1 to 3:1, preferably 0.25:1 to 3:1, and more preferably 1:1.

[0027] Thirdly, this application provides a method for preparing saturated aldehydes / ketones by catalyzing α,β-unsaturated aldehydes / ketones using the above-mentioned supported nano-cubic nickel-gallium alloy catalyst, which includes the following steps: mixing the supported nano-cubic nickel-gallium alloy catalyst, the α,β-unsaturated aldehyde / ketone substrate and the solvent, and reacting under a hydrogen atmosphere at a pressure of 1 MPa to 5 MPa, preferably 1 MPa, at a temperature of 80 to 150 °C, preferably 100 °C, for a reaction time of 0.5 h to 6 h, preferably 3 h, to obtain the corresponding saturated aldehyde / ketone compound.

[0028] In conjunction with the third aspect, in one feasible implementation, the α,β-unsaturated aldehyde / ketone substrate is selected from...

[0029] At least one of them.

[0030] In conjunction with the third aspect, in one feasible embodiment, the mass ratio of the supported nanocubic nickel-gallium alloy catalyst to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is from 60 mg:1 mmol to 300 mg:1 mmol, preferably from 100 mg:1 mmol to 200 mg:1 mmol, and more preferably from 150 mg:1 mmol.

[0031] In conjunction with the third aspect, in one feasible embodiment, the volume ratio of the solvent to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is from 20 mL:1 mmol to 3 mL:1 mmol, preferably from 15 mL:1 mmol to 7 mL:1 mmol, and more preferably from 10 mL:1 mmol.

[0032] In conjunction with the third aspect, in one feasible embodiment, the solvent is at least one selected from deionized water, tetrahydrofuran, ethanol, isopropanol, acetonitrile, and 2-methyltetrahydrofuran, preferably deionized water. Deionized water is cheaper in both reagent and post-treatment costs, and it is environmentally friendly, making it a green reagent.

[0033] In conjunction with the third aspect, in one feasible embodiment, the catalyst can be reused after being washed with ethanol and ethyl acetate respectively after the catalytic reaction, and then vacuum dried at 50℃~70℃ for 12h~24h.

[0034] The technical solution provided in this application has at least the following advantages compared to the prior art:

[0035] 1. The supported nanocubic nickel-gallium alloy catalyst of this application possesses a regular nanocubic structure and exhibits excellent catalytic activity, chemoselectivity, stereoselectivity, and stability in the selective hydrogenation of α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones. This is due, on the one hand, to the significant alteration of the morphology and electronic structure of the original nickel nanoparticles by introducing gallium as a second functional component, thus significantly changing the adsorption configuration of the α,β-unsaturated aldehyde / ketone substrate molecules and exhibiting excellent C=C bond hydrogenation selectivity, thereby improving the selectivity of the selective hydrogenation of α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones. On the other hand, the core-shell structure synthesized in situ through carbothermal reduction and nitrogen doping effectively increase the active sites on the catalyst surface and enhance the interaction between the nickel-gallium alloy nanoparticles and the carbon support, increasing the dispersion of the nickel-gallium alloy nanocubic particles on the carbon support surface and effectively suppressing the loss and aggregation of the nickel-gallium alloy active components during the reaction process, allowing the catalyst to maintain its activity even after six cycles.

[0036] Furthermore, the supported nano-cubic nickel-gallium alloy catalyst according to this application is a non-noble metal heterogeneous catalyst. Compared with the noble metal catalysts commonly used for α,β-unsaturated aldehydes / ketones, it is inexpensive, abundant, easy to separate and recover, and highly selective in generating saturated aldehyde / ketone compounds.

[0037] 2. The method for preparing the supported nano-cubic nickel-gallium alloy catalyst according to this application uses water as a solvent and renewable biomass bamboo shoots as raw material. A hydrothermal-pyrolysis method is employed to prepare nitrogen-doped porous carbon materials. The preparation process does not involve the addition of any chemicals or chemical activation; it is simple, green, and scalable. Furthermore, since bamboo shoots themselves contain approximately 8 wt% nitrogen-containing compounds (such as proteins, amino acids, and vitamins), nitrogen doping can be achieved without the addition of additional nitrogen source materials, further reducing costs.

[0038] Furthermore, by adding a second functional component, gallium, and undergoing secondary calcination, in-situ structural reconstruction can be performed to generate a nanocubic structure, thus obtaining the supported nanocubic nickel-gallium alloy catalyst. This preparation method has advantages such as wide availability of resources, low cost, and simple operation of each step, and has broad application prospects.

[0039] 3. The method for preparing saturated aldehydes / ketones by catalytic hydrogenation of α,β-unsaturated aldehydes / ketones using the above-mentioned supported nano-cubic nickel-gallium alloy catalyst, according to this application, employs hydrogen as a reducing agent, which is convenient, effective, and has high atom utilization. Furthermore, this method exhibits good substrate versatility for the selective hydrogenation of various α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones. In addition, this method uses deionized water as a solvent, resulting in lower reagent and post-processing costs, and is environmentally friendly, making it a green solvent. This method provides a feasible solution for improving the selective hydrogenation of α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones and has practical application value. Attached Figure Description

[0040] Figure 1 This is a high-resolution transmission electron microscope (HR-TEM) image of a supported nano-cubic nickel-gallium alloy catalyst prepared according to Example 1 of an embodiment of this application.

[0041] Figure 2 X-ray diffraction (XRD) data of a supported nano-cubic nickel-gallium alloy catalyst prepared according to Example 1 of an embodiment of this application. Detailed Implementation

[0042] To enable those skilled in the art to more clearly understand this application, the following detailed description, in conjunction with embodiments, is provided. Before proceeding with the description, it should be understood that the terminology used in this specification and the appended claims should not be construed as limited to its general or dictionary meaning, but rather should be interpreted according to the meaning and concept corresponding to the technical aspects of this application, based on the principle that the inventor is allowed to appropriately define the terminology for the best interpretation. Therefore, the description presented herein is merely illustrative of preferred examples and is not intended to limit the scope of this application. It should be understood that other equivalent or improved methods can be obtained from it without departing from the spirit and scope of this application, and the scope of protection claimed in this application shall be determined by the scope defined in the claims. Unless otherwise specified, the reagents and instruments used in the following embodiments are commercially available products.

[0043] In a first aspect, this application provides a supported nanocubic nickel-gallium alloy catalyst, which includes a nitrogen-doped porous carbon material as a support and metallic nickel-gallium alloy nanocubic particles as an active component, wherein the catalyst has a regular nanocubic structure and a core-shell structure with the metallic nickel-gallium alloy nanocubic particles as the core and the nitrogen-doped porous carbon material as the shell.

[0044] In conjunction with the first aspect, in one feasible embodiment, the nickel content in the supported nano-cubic nickel-gallium alloy catalyst is 0.1 wt% to 10 wt% (e.g., it can be 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.7 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, 8.0 wt%, 8.5 wt%, 9.0 wt%, 9.5 wt%, or 10 wt%, or any value within the range), preferably, the nickel content in the supported nano-cubic nickel-gallium alloy catalyst is 2 wt% to 8 wt%, and more preferably, the nickel content in the supported nano-cubic nickel-gallium alloy catalyst is 4 wt% to 7 wt%.

[0045] In conjunction with the first aspect, in one feasible embodiment, the gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 0.1 wt% to 8 wt% (for example, it can be 0.1 wt%, 0.2 wt%, 0.5 wt%, 0.7 wt%, 1.0 wt%, 1.5 wt%, 2.0 wt%, 2.5 wt%, 3.0 wt%, 3.5 wt%, 4.0 wt%, 4.5 wt%, 5.0 wt%, 5.5 wt%, 6.0 wt%, 6.5 wt%, 7.0 wt%, 7.5 wt%, or 8.0 wt%, or any value within the range), preferably, the gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 2 wt% to 6 wt%, and more preferably, the gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 3 wt% to 5 wt%. Within the above-mentioned content range, the supported nano-cubic nickel-gallium alloy catalyst can effectively utilize its ability to selectively hydrogenate α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones.

[0046] In conjunction with the first aspect, in one feasible embodiment, the nitrogen-doped porous carbon material has a density of 50 μm. 2 / g~1000m 2 / g (for example, 50m) 2 / g、70m 2 / g, 100m 2 / g, 150m 2 / g、200m 2 / g、250m 2 / g、300m 2 / g, 350m 2 / g、400m 2 / g、450m 2 / g, 50m 2 / g、550m 2 / g、600m 2 / g、650m 2 / g、700m 2 / g、750m 2 / g、800m 2 / g、850m 2 / g、900m 2 / g、950m 2 / g or 1000m 2The specific surface area ( / g, or any value within the range) and 1wt% to 20wt% (e.g., can be 1wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt%, 5.5wt%, 6wt%, 6.5wt%, 7wt%, 7.5wt%, 8wt%, 8.5wt%, 9wt%, 9.5wt%, 10wt%) The nitrogen content is 11 wt%, 11.5 wt%, 12 wt%, 12.5 wt%, 13 wt%, 13.5 wt%, 14 wt%, 14.5 wt%, 15 wt%, 15.5 wt%, 16 wt%, 16.5 wt%, 17 wt%, 17.5 wt%, 18 wt%, 18.5 wt%, 19 wt%, 19.5 wt%, or 20 wt%, or any value within the range stated. Preferably, the nitrogen-doped porous carbon material has a nitrogen content of 100 μm. 2 / g~500m 2 The nitrogen-doped porous carbon material has a specific surface area of ​​ / g and a nitrogen content of 1wt% to 10wt%. By giving the nitrogen-doped porous carbon material a suitable specific surface area and nitrogen content, nickel-gallium alloy nanocubic particles as active components can be effectively loaded and encapsulated.

[0047] Secondly, this application provides a method for preparing the above-mentioned supported nano-cubic nickel-gallium alloy catalyst, which includes the following steps:

[0048] (1) Peel and wash fresh bamboo shoots, slice them, dry them and grind them into powder. Mix them with water and carry out a hydrothermal reaction at 100-230°C, preferably 180°C, for 2-10 hours, preferably 4-6 hours. Then filter, wash and dry to obtain nitrogen-doped porous carbon material precursor.

[0049] (2) The nitrogen-doped porous carbon material precursor obtained in step (1) is impregnated with an aqueous solution of adsorbent nickel salt, dried, and ground to obtain adsorbent particles; and

[0050] (3) The adsorbent particles obtained in step (2) are calcined in an inert atmosphere (such as nitrogen or argon) at a temperature of 500-1000°C, preferably 800°C, for 1-5 hours, preferably 2-3 hours, then cooled and ground to obtain a supported nickel-containing nanoparticle catalyst.

[0051] (4) The supported nickel-containing nanoparticle catalyst obtained in step (3) is impregnated with an aqueous solution of gallium salt, dried, and ground to obtain adsorbed particles; and

[0052] (5) The adsorption particles obtained in step (4) are calcined for 1 to 5 hours, preferably 2 to 3 hours, in an inert atmosphere (such as nitrogen or argon) at 500 to 1000°C, preferably 800°C, to generate a nano cubic structure. The particles are then cooled and ground to obtain the supported nano cubic nickel-gallium alloy catalyst.

[0053] The preparation method of the supported nano-cubic nickel-gallium alloy catalyst according to this application uses water as a solvent and renewable biomass bamboo shoots as raw materials. It adopts a hydrothermal-pyrolysis method to prepare nitrogen-doped porous carbon materials. No chemicals are added during the preparation process, and no chemical activation is required. The process is simple, green, and can be prepared on a large scale.

[0054] Furthermore, by adding a second functional component, gallium, and undergoing secondary calcination, in-situ structural reconstruction can be performed to generate a nanocubic structure, thus obtaining the supported nanocubic nickel-gallium alloy catalyst. This preparation method has advantages such as wide availability of resources, low cost, and simple operation of each step, and has broad application prospects.

[0055] In conjunction with step (1) of the second aspect, the bamboo shoots are seedlings of the plant Bambusoideae, aged 0-3 months. Furthermore, since bamboo shoots themselves contain approximately 8 wt% nitrogen-containing compounds (such as proteins, amino acids, and vitamins), nitrogen doping can be achieved through processing without the need for additional nitrogen source materials, further reducing costs.

[0056] In conjunction with step (1) of the second aspect, it can be further described as follows: fresh bamboo shoots that have been peeled and washed are sliced ​​and dried at 20-120°C, preferably 70°C, for 5-48 hours, preferably 24 hours, to obtain a brown solid. The solid is then ground into powder, and the powder is mixed evenly with water and transferred to a hydrothermal reactor lined with polytetrafluoroethylene. The mixture is then subjected to a hydrothermal reaction at 100-230°C for 2-10 hours, preferably 4-6 hours. After filtration and washing, the mixture is dried at 20-120°C, preferably 70°C, for 5-48 hours, preferably 24 hours, to obtain a nitrogen-doped porous carbon material precursor.

[0057] In conjunction with step (2) of the second aspect, the immersion temperature is 40-80°C, preferably 60°C; the immersion time is 1-4 hours, preferably 2 hours.

[0058] In conjunction with step (2) of the second aspect, the concentration of nickel in the nickel salt aqueous solution is 0.004 to 0.04 mol / L, preferably 0.01 mol / L.

[0059] In conjunction with step (2) of the second aspect, the nickel salt in the nickel salt aqueous solution can be at least one selected from nickel acetate hydrate, nickel nitrate, nickel chloride, nickel carbonate, and nickel sulfate, preferably nickel acetate hydrate. The nickel salt is one of several commonly used inorganic nickel acid salts, with a wide range of choices.

[0060] In conjunction with step (2) of the second aspect, the weight ratio of the nitrogen-doped porous carbon material precursor to the nickel salt is 50:1 to 150:1 (for example, it can be 50:1, 60:1, 70:1, 80:1, 90:1, 100:1, 110:1, 120:1, 130:1, 140:1 or 150:1, or any value within the range), preferably 100:1.

[0061] In conjunction with step (4) of the second aspect, the immersion temperature is 80-120°C, preferably 100°C; the immersion time is 4-24 hours, preferably 12-18 hours.

[0062] In conjunction with step (4) of the second aspect, the concentration of gallium in the gallium salt aqueous solution is 0.004 to 0.04 mol / L, preferably 0.01 mol / L.

[0063] In conjunction with step (4) of the second aspect, the gallium salt in the gallium salt aqueous solution can be at least one selected from gallium nitrate hydrate, gallium chloride, gallium ethoxide, gallium isopropoxide, gallium acetylacetonate, and gallium triethylidene, preferably gallium nitrate hydrate. The gallium salt is a common inorganic acid gallium salt, widely available, and with low impurity content, thereby improving the catalytic performance of the catalyst.

[0064] In conjunction with step (4) of the second aspect, the molar ratio of the gallium salt to the nickel salt in step (2) is 0:1 (but not 0) to 3:1 (for example, it can be 0.25:1, 0.5:1, 0.75:1, 1:1, 1.25:1, 1.5:1, 1.75:1, 2:1, 2.25:1, 2.5:1, 2.75:1 or 3:1, or any value within the range), preferably 1:1.

[0065] Thirdly, this application provides a method for preparing saturated aldehydes / ketones by catalyzing α,β-unsaturated aldehydes / ketones using the above-mentioned supported nano-cubic nickel-gallium alloy catalyst, which includes the following steps: mixing the supported nano-cubic nickel-gallium alloy catalyst, the α,β-unsaturated aldehyde / ketone substrate and the solvent, and reacting under a hydrogen atmosphere at a pressure of 1 MPa to 5 MPa, preferably 1 MPa, at a temperature of 80 to 150 °C, preferably 100 °C, for a reaction time of 0.5 h to 6 h, preferably 3 h, to obtain the corresponding saturated aldehyde / ketone compound.

[0066] In conjunction with the third aspect, in one feasible embodiment, the reaction pressure of the hydrogenation reaction can be 1 MPa to 5 MPa (for example, it can be 1 MPa, 1.5 MPa, 2 MPa, 2.5 MPa, 3 MPa, 3.5 MPa, 4 MPa, 4.5 MPa, or 5 MPa, or any value within the range), preferably 1 MPa. The reaction temperature can be 80°C to 150°C (for example, it can be 80°C, 90°C, 100°C, 110°C, 120°C, 130°C, 140°C, or 150°C, or any value within the range), preferably 100°C. The reaction time can be 0.5h to 6h (for example, it can be 0.5h, 1h, 2h, 3h, 4h, 5h or 6h, or any value within the range), preferably 3h; within this pressure, temperature and time range, the supported nano-cubic nickel-gallium alloy catalyst can effectively promote the catalytic preparation of saturated aldehydes / ketones from α,β-unsaturated aldehydes / ketones.

[0067] In conjunction with the third aspect, in one feasible embodiment, the molar ratio of the supported nanocubic nickel-gallium alloy catalyst to the α,β-unsaturated aldehyde / ketone substrate is from 60 mg:1 mmol to 300 mg:1 mmol (e.g., 60 mg:1 mmol, 70 mg:1 mmol, 80 mg:1 mmol, 0 mg:1 mmol, 100 mg:1 mmol, 110 mg:1 mmol, 120 mg:1 mmol, 130 mg:1 mmol, 140 mg:1 mmol, 150 mg:1 mmol, 160 mg:1 mmol, etc.). The recommended ratios are 150 mg:1 mmol, 170 mg:1 mmol, 180 mg:1 mmol, 190 mg:1 mmol, 200 mg:1 mmol, 210 mg:1 mmol, 220 mg:1 mmol, 230 mg:1 mmol, 240 mg:1 mmol, 250 mg:1 mmol, 260 mg:1 mmol, 270 mg:1 mmol, 280 mg:1 mmol, 290 mg:1 mmol, or 300 mg:1 mmol (or any value within the range), preferably 150 mg:1 mmol. Within this ratio range, the supported nanocubic nickel-gallium alloy catalyst can effectively promote the selective hydrogenation of α,β-unsaturated aldehydes / ketones to prepare saturated aldehydes / ketones.

[0068] In conjunction with the third aspect, in one feasible embodiment, the volume ratio of the solvent to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is from 20 mL:1 mmol to 3 mL:1 mmol (e.g., 20 mL:1 mmol, 19 mL:1 mmol, 18 mL:1 mmol, 17 mL:1 mmol, 16 mL:1 mmol, 15 mL:1 mmol, 14 mL:1 mmol, 13 mL:1 mmol, 12 mL:1 mmol, 11 mL:1 mmol, 10 mL:1 mmol, 9 mL:1 mmol, 8 mL:1 mmol, 7 mL:1 mmol, 6 mL:1 mmol, 5 mL:1 mmol, 4 mL:1 mmol, or 3 mL:1 mmol, or any value within the range), preferably from 15 mL:1 mmol to 7 mL:1 mmol, and more preferably 10 mL:1 mmol. Within this ratio range, the supported nanocubic nickel-gallium alloy catalyst can effectively promote the selective hydrogenation of α,β-unsaturated aldehydes / ketones to prepare saturated aldehydes / ketones.

[0069] In conjunction with the third aspect, in one feasible implementation, the α,β-unsaturated aldehyde / ketone substrate is selected from... At least one of them.

[0070] In conjunction with the third aspect, in one feasible embodiment, the solvent is at least one selected from deionized water, tetrahydrofuran, ethanol, isopropanol, acetonitrile, and 2-methyltetrahydrofuran, preferably deionized water. Deionized water is cheaper in both reagent and post-treatment costs, and it is environmentally friendly, making it a green reagent.

[0071] In conjunction with the third aspect, in one feasible embodiment, the catalyst can be reused after being washed with ethanol and ethyl acetate respectively after the catalytic reaction, and then vacuum dried at 50℃~70℃ for 12h~24h.

[0072] The method for preparing saturated aldehydes / ketones by catalytic hydrogenation of α,β-unsaturated aldehydes / ketones using the aforementioned supported nano-cubic nickel-gallium alloy catalyst, as described in this application, employs hydrogen as a reducing agent. This method is convenient, effective, and has high atom utilization. Furthermore, it exhibits good substrate versatility for the selective hydrogenation of various α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones. In addition, the method uses deionized water as a solvent, resulting in lower reagent and post-processing costs, and is environmentally friendly, making it a green solvent. This method provides a feasible solution for improving the selective hydrogenation of α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones and has practical application value.

[0073] Example

[0074] Instruments used for material characterization:

[0075] Transmission electron microscope: Model H-7650, manufactured by Hitachi, Japan.

[0076] Physical adsorption instrument: Model ASAP2020, manufactured by Micrometritics, Inc., USA.

[0077] ICP-AES: Model 5300DV, manufactured by PerkinElmer Optima, USA.

[0078] XRD: Model number D8 Advance, manufactured by Bruker GmbH, Germany.

[0079] Example 1

[0080] The supported nanocubic nickel-gallium alloy catalyst according to this application is prepared using the following method.

[0081] (1) Peel and wash the fresh bamboo shoots and slice them. Dry them at 70℃ for 24h. Grind the resulting brown solid into powder. Take 4g of powder and add it to 40mL of deionized water. Stir and mix evenly and transfer it to a hydrothermal reactor with a polytetrafluoroethylene liner. React at 180℃ for 5.5h. Filter, wash, and dry at 70℃ for 24h to obtain a brown solid nitrogen-doped porous carbon material precursor.

[0082] (2) Dissolve 0.4 mmol Ni(OAc)₂·4H₂O in 40 mL of deionized water. After it is completely dissolved, add 1 g of the nitrogen-doped porous carbon material precursor prepared in step (1). Stir at 60 °C for 2 h, dry at 100 °C for 10 h, and grind to obtain adsorption particles; and

[0083] (3) The adsorption particles obtained in step (2) are placed in a tube furnace and calcined at 800°C for 2 hours in a nitrogen atmosphere. After the tube furnace is cooled to room temperature, the sample is taken out and ground to obtain the in-situ synthesized supported nickel nanoparticle catalyst with core-shell structure.

[0084] (4) Dissolve 0.4 mmol Ga(NO3)·xH2O in 40 mL of deionized water. After complete dissolution, add the core-shell structured supported nickel nanoparticle catalyst prepared in step (3), stir at 100 °C, dry for 12 h, and grind to obtain adsorbent particles; and

[0085] (5) The adsorption particles obtained in step (4) are placed in a tube furnace and calcined for 2 hours at 800°C in a nitrogen atmosphere to reconstruct the structure in situ and generate a nano cubic structure. After the tube furnace is cooled to room temperature, the sample is taken out and ground to obtain a supported nano cubic nickel-gallium alloy catalyst with a core-shell structure.

[0086] In this supported nano-cubic nickel-gallium alloy catalyst, the nickel loading was determined to be 4.94 wt% and the gallium loading to be 3.54 wt% by ICP-AES; the nitrogen content was determined to be 4.20 wt% by elemental analysis; and the specific surface area was determined to be 281.1 m² / s² by N₂ adsorption-desorption method. 2 g -1 .

[0087] Figure 1 High-resolution transmission electron microscopy (HR-TEM) image of the supported nano-cubic nickel-gallium alloy catalyst prepared according to this embodiment. Figure 1 As shown, the nickel-gallium alloy nanocubic particles in this material are encapsulated by a carbon layer and are uniformly dispersed. The size of the nickel-gallium alloy nanocubic particles is approximately 22 nm.

[0088] Figure 2 The image shows X-ray diffraction (XRD) data of the supported nano-cubic nickel-gallium alloy catalyst prepared according to this embodiment. Figure 2 As shown, a NiGa alloy is formed by adding a second functional component, gallium.

[0089] Example 2-11: Effects of different substrates

[0090] The method for preparing saturated aldehydes / ketones by catalyzing α,β-unsaturated aldehydes / ketones using a supported nano-cubic nickel-gallium alloy catalyst according to this application includes:

[0091] In a high-pressure reactor equipped with a stirrer, 30 mg of the supported nano-cubic nickel-gallium alloy catalyst prepared in Example 1 was added, followed by 0.2 mmol of cinnamaldehyde. Then, 2 ml of deionized water was added for dispersion and dissolution. The reactor was purged three times with H2 to replace the air. Subsequently, 1 MPa of H2 was introduced into the reactor to provide a hydrogen source for the reaction. The reaction was stirred at 100 °C for 3 h, cooled to room temperature, and the products were analyzed by gas chromatography. The results showed that the conversion rate of cinnamaldehyde was >99%, and the selectivity of the product phenylpropionaldehyde (a C=C bond hydrogenation product) was >99%.

[0092] Similar to the above steps, by changing the type of α,β-unsaturated aldehyde / ketone substrate, catalytic hydrogenation was performed using the supported nano-cubic nickel-gallium alloy catalyst according to Example 1 of this application to obtain the corresponding saturated aldehyde / ketone compounds. Specific substrate conversions and selectivity of the saturated aldehyde / ketone derivatives are shown in Table 1.

[0093] Table 1

[0094]

[0095] As can be seen from Table 1 above, the method for preparing saturated aldehydes / ketones using a supported nano-cubic nickel-gallium alloy catalyst according to this application has good selectivity and conversion rate for various α,β-unsaturated aldehydes / ketones.

[0096] Examples 12-17: Effects of Different Solvents

[0097] Following the same operating steps as in Example 2, cinnamaldehyde was selectively hydrogenated to phenylpropionaldehyde using different solvents in the presence of the supported nano-cubic nickel-gallium alloy catalyst prepared in Example 1. The results are shown in Table 2.

[0098] Table 2

[0099]

[0100] As shown in Table 2, the choice of solvent has a significant impact on the selective hydrogenation of α,β-unsaturated aldehydes / ketones to saturated aldehydes / ketones. In particular, the conversion rate and selectivity are both excellent when deionized water is used as the solvent. This indicates that aqueous solvents enhance hydrogenation via C=C bonds and inhibit hydrogenation via C=O bonds. This is because the interaction of water with electrons and hydrogen bonds at C=C bonds and catalyst surface sites makes selective adsorption via C=C bonds the preferred hydrogenation step, thereby accelerating reaction kinetics and improving catalytic selectivity.

[0101] Examples 18-23: Effect of different nickel-gallium ratios (keeping nickel content constant)

[0102] Following the same operating steps as in Example 1, only the gallium salt concentration was changed to prepare catalysts with different nickel-gallium ratios;

[0103] Following the same operating steps as in Example 2, only the reaction temperature was changed to 90°C, allowing for a comparison of the effects of different nickel-gallium ratio catalysts on the selective hydrogenation of cinnamaldehyde to phenylpropionaldehyde. The results are shown in Table 3.

[0104] Table 3

[0105]

[0106] The number before Ga in the catalyst product name indicates the molar ratio of Ga to Ni. For example, 0.5Ga-Ni@NC-800 means that the molar ratio of Ga to Ni is 0.5:1, and the catalyst undergoes two calcination steps at 800℃.

[0107] As can be seen from the data in Table 3, different nickel-gallium ratios have a certain impact on the selective hydrogenation of α,β-unsaturated aldehydes / ketones to prepare saturated aldehydes / ketones. As shown in Example 18, when the second functional component gallium is not added, i.e., the supported nickel-containing nanoparticle catalyst prepared in step (3) of Example 1, is inert for the selective hydrogenation of α,β-unsaturated aldehydes / ketones to prepare saturated aldehydes / ketones. However, with the addition of the second functional component gallium, the reaction conversion rate gradually increases. As shown in Examples 19-23, there is a volcano-shaped curve between gallium content and reaction conversion rate, and the supported nanocubic nickel-gallium alloy catalyst prepared in Example 1 has the best catalytic activity (Example 21). However, as the gallium content further increases, the Ni3Ga crystal structure is destroyed, resulting in a gradual decrease in reaction activity. In addition, as shown in Example 24, Ga@NC-800 prepared by adding only Ga salt has no reaction activity because Ga is an inert metal in the hydrogenation reaction.

[0108] Example 25: Selective addition of cinnamaldehyde using the supported nano-cubic nickel-gallium alloy catalyst according to this application Gram-scale scale-up experiment of hydrogen-produced phenylpropionaldehyde

[0109] In a high-pressure reactor equipped with a stirrer, 300 mg of the supported nano-cubic nickel-gallium alloy catalyst prepared in Example 1 was added, followed by 2 mmol of cinnamaldehyde, and then 20 ml of deionized water solvent for dispersion and dissolution. The reactor was then purged with H2 three times to replace the air. Afterward, 1 MPa of H2 was introduced into the reactor to provide a hydrogen source for the reaction. The reaction was stirred at 100 °C for 3 h, cooled to room temperature, and the products were analyzed by gas chromatography. The results showed that the conversion rate of cinnamaldehyde was 94%, and the selectivity of the product phenylpropionaldehyde was >99%.

[0110] The specific embodiments described above are merely preferred embodiments for explaining this application and are not intended to limit this application. Those skilled in the art can make modifications without creative contribution as needed after reading this specification. However, any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method for preparing saturated aldehydes / ketones using a supported nano-cubic nickel-gallium alloy catalyst, characterized in that, Includes the following steps: The supported nano-cubic nickel-gallium alloy catalyst, α,β-unsaturated aldehyde / ketone substrate, and solvent were mixed and reacted under a hydrogen atmosphere at a pressure of 1 MPa to 5 MPa, a temperature of 80 to 150 °C, and a reaction time of 0.5 h to 6 h to obtain the corresponding saturated aldehyde / ketone compound. The solvent was deionized water. The supported nanocubic nickel-gallium alloy catalyst is characterized by comprising a nitrogen-doped porous carbon material as a support and metallic nickel-gallium alloy nanocubic particles as an active component. The catalyst has a regular nanocubic structure and a core-shell structure with the metallic nickel-gallium alloy nanocubic particles as the core and the nitrogen-doped porous carbon material as the shell. The size of the nanocubic structure is 5 to 100 nm. Based on the total weight of the catalyst, the nickel content is 0.1 wt% to 10 wt%, and the gallium content is 0.1 wt% to 8 wt%, with a gallium to nickel molar ratio of 0.25:1 to 3:

1.

2. The method according to claim 1, characterized in that, In the method described, the hydrogen pressure is 1 MPa, the temperature is 100°C, and the reaction time is 3 h.

3. The method according to claim 1, characterized in that, The molar ratio of gallium to nickel in the supported nano-cubic nickel-gallium alloy catalyst is 1:

1.

4. The method according to claim 1, characterized in that, The nickel content in the supported nano-cubic nickel-gallium alloy catalyst is 2 wt% to 8 wt%.

5. The method according to claim 1, characterized in that, The nickel content in the supported nano-cubic nickel-gallium alloy catalyst is 4 wt% to 7 wt%.

6. The method according to claim 1, characterized in that, The gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 2 wt% to 6 wt%.

7. The method according to claim 1, characterized in that, The gallium content in the supported nano-cubic nickel-gallium alloy catalyst is 3 wt% to 5 wt%.

8. The method according to claim 1, characterized in that, In the supported nano-cubic nickel-gallium alloy catalyst, the nitrogen-doped porous carbon material has a density of 50 μm. 2 / g~1000 m 2 Specific surface area per g and nitrogen content of 1 wt% to 20 wt%.

9. The method according to claim 1, characterized in that, In the supported nano-cubic nickel-gallium alloy catalyst, the nitrogen-doped porous carbon material has a density of 100 μm. 2 / g~500 m 2 Specific surface area per g and nitrogen content of 1 wt% to 10 wt%.

10. The method according to claim 1, characterized in that, The mass ratio of the supported nanocubic nickel-gallium alloy catalyst to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is from 60 mg:1 mmol to 300 mg:1 mmol.

11. The method according to claim 1, characterized in that, The mass ratio of the supported nanocubic nickel-gallium alloy catalyst to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is 150 mg: 1 mmol.

12. The method according to claim 1, characterized in that, The volume ratio of the solvent to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is from 20 mL:1 mmol to 3 mL:1 mmol.

13. The method according to claim 1, characterized in that, The volume ratio of the solvent to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is from 15 mL:1 mmol to 7 mL:1 mmol.

14. The method according to claim 1, characterized in that, The volume ratio of the solvent to the molar amount of the α,β-unsaturated aldehyde / ketone substrate is 10 mL:1 mmol.

15. The method according to claim 1, characterized in that, The α,β-unsaturated aldehyde / ketone is selected from... , , , , , , , , , At least one of them.

16. The method according to claim 1, characterized in that, The catalyst was washed with ethanol and ethyl acetate after the catalytic reaction, and then dried under vacuum at 50 °C to 70 °C for 12 h to 24 h before being reused.

Images