Ni-Cu bimetallic catalyst and preparation method and application thereof

Abstract

The invention relates to the technical field of catalysts, in particular to a Ni-Cu bimetallic catalyst and a preparation method and application thereof. The preparation method of the Ni-Cu bimetallic catalyst is characterized by comprising the following steps: S1, dissolving Ni (NO3) 2.6 H2O and Cu (NO3) 2.3 H2O in water to obtain a solution A; s2, NaOH and Na2CO3 are dissolved in water, and a solution B is obtained; s3, slowly adding the solution B into the solution A, and stirring to obtain a solution C; s4, carrying out a hydrothermal reaction on the solution C, after the reaction is finished, cooling, taking a precipitate, carrying out suction filtration, washing to be neutral, removing surface moisture, and then drying and grinding to obtain a first precursor; s5, roasting the first precursor to obtain a second precursor; and S6, the second precursor is reduced, and the Ni-Cu bimetallic catalyst is obtained. The Ni-Cu bimetallic catalyst prepared according to the molar ratio of Ni to Cu of 4: 1 catalyzes 3-hydroxybutyraldehyde hydrogenation reaction to synthesize 1, 3-BDO, the conversion rate of 3-HBA is 98.85%, and the selectivity and yield of 1, 3-BDO are 93.28% and 92.20% respectively.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalysts, more particularly to a Ni-Cu bimetallic catalyst and a preparation method and application thereof. BACKGROUND

[0002] 1,3-Butanediol (1,3-BDO) is a colorless transparent viscous liquid, with high boiling point, low volatility, excellent water solubility, mild moisturizing property, strong organic component solubility and low biological toxicity, etc. It has multiple characteristics, making it irreplaceable in many fields. In the chemical industry, it can be used as a core monomer to participate in the synthesis of alkyd resin and polyurethane coating, and also as a plasticizer and modifier to optimize the comprehensive performance of polymer materials. In the pharmaceutical industry, it can be used as a key pharmaceutical intermediate to synthesize R,S-1,3-butanediol acetyl acetic acid diester and important products such as beta-lactam antibiotics. In the daily chemical field, about 35% of 1,3-butanediol is used in cosmetics and daily necessities such as moisturizing cream, skin toner, emulsion, shampoo and toothpaste. With the advantages of low irritation and refreshing skin feel, it has become the preferred raw material. With the breakthrough of green synthesis technology and the continuous expansion of downstream application fields, the research and development of 1,3-butanediol not only has important academic value, but also shows broad prospects in promoting the upgrading and sustainable development of related industries.

[0003] Currently, there are three processes for producing 1,3-butanediol, namely acetaldehyde condensation hydrogenation, formaldehyde propylene condensation hydrolysis and biosynthesis. As the mainstream route, acetaldehyde condensation hydrogenation uses acetaldehyde as the raw material, which is condensed to form 3-hydroxybutyraldehyde in the presence of an alkaline catalyst, and then catalytically hydrogenated to obtain 1,3-butanediol. The traditional batch process is generally used in the acetaldehyde condensation stage, and the core bottleneck is the dependence on liquid alkali catalysts. Such catalysts are highly corrosive and cannot be recycled. After the reaction, they need to be quenched with acid, which generates a large amount of salt-containing wastewater, increasing the environmental pressure. Currently, research mainly focuses on replacing liquid alkali catalysts with new solid alkali catalysts to effectively solve the above-mentioned bottlenecks. In the hydrogenation stage, traditional processes often use Raney nickel catalysts to react in a high-pressure reaction kettle. Although the catalyst has stable activity and can be partially recycled, it is prone to particle size refinement due to its low strength, which increases the difficulty of separation. At the same time, high-pressure reaction conditions require high equipment requirements and high energy consumption, and the catalyst itself is prone to spontaneous combustion, which significantly increases the production cost and operation risk. SUMMARY

[0004] The present application provides a Ni-Cu bimetallic catalyst and a preparation method and application thereof to solve the above problems.

[0005] The present application aims to provide an efficient and environmentally friendly process for synthesizing 1,3-butanediol by hydrogenation of 3-hydroxybutyraldehyde under atmospheric pressure.

[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: In a first aspect, the present invention provides a method for preparing a Ni-Cu bimetallic catalyst, comprising the following steps: S1. Dissolve Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in water to obtain solution A; S2. Dissolve NaOH and Na2CO3 in water to obtain solution B; S3. Slowly add solution B to solution A and stir to obtain solution C; S4. Solution C is subjected to a hydrothermal reaction. After the reaction is completed, it is cooled, the precipitate is filtered and washed until neutral, the surface moisture is removed, and then dried and ground to obtain the first precursor. S5. The first precursor is calcined to obtain the second precursor; S6. The second precursor is reduced to obtain a Ni-Cu bimetallic catalyst; The molar ratio of Ni(NO3)2·6H2O to Cu(NO3)2·3H2O is (3~8):1 (e.g., 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, 6.5:1, 7:1, 7.5:1, 8:1, etc.).

[0007] In the preferred embodiment, in step S1, the molar ratio of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O is 4:1.

[0008] In the preferred embodiment, the molar ratio of NaOH to Na2CO3 in step S2 is 2:1.

[0009] In the preferred embodiment, the molar ratio of Ni(NO3)2·6H2O to NaOH is 1:2.

[0010] In the preferred embodiment, in step S3, the stirring conditions are stirring at 25°C and 50~1500rpm for 2 hours; in step S4, the hydrothermal reaction conditions are hydrothermal reaction at 120°C for 12 hours, and the drying conditions are drying at 80°C for 12 hours.

[0011] In the preferred embodiment, the calcination conditions are: heating to 500℃ at a heating rate of 5℃ / min and calcining for 4 hours.

[0012] In the preferred embodiment, in step S6, the second precursor is placed in a reactor, H2 is introduced into the reactor under a nitrogen atmosphere, and the temperature is raised to 380℃ for a reduction reaction for 2 hours to obtain a Ni-Cu bimetallic catalyst.

[0013] In a second aspect, the present invention provides a Ni-Cu bimetallic catalyst prepared by any of the above methods.

[0014] In a third aspect, the present invention provides the application of the above-mentioned Ni-Cu bimetallic catalyst in the catalytic hydrogenation of 3-hydroxybutyraldehyde to prepare 1,3-butanediol.

[0015] In a preferred embodiment, the method for preparing 1,3-butanediol by hydrogenation of 3-hydroxybutyraldehyde using a Ni-Cu bimetallic catalyst involves adding the Ni-Cu bimetallic catalyst and 3-hydroxybutyraldehyde to an organic solvent at a mass-to-volume ratio of (0.4~1.2):20 (g / mL), and reacting the mixture at 35~75℃ for 4~12 h under a hydrogen atmosphere; the organic solvent is methanol and / or ethanol.

[0016] Beneficial effects of the present invention This invention utilizes Ni(NO3)2·6H2O and Cu(NO3)2·3H2O as raw materials, and NaOH and Na2CO3 as precipitants. A Ni-Cu catalyst prepared by hydrothermal reduction at 380℃ exhibits excellent activity in the catalytic hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol under ambient pressure. The optimal Ni:Cu ratio is 4:1, and the optimal reaction conditions are: 1g catalyst in 20mL of 3-hydroxybutyraldehyde solution, 100mL of ethanol as solvent, a reaction time of 12h, and a reaction temperature of 75℃. Under these conditions, the conversion rate of 3-HBA is 98.85%, and the selectivity and yield of 1,3-BDO are 93.28% and 92.20%, respectively. The Ni-Cu bimetallic catalyst provided by this invention can catalyze the synthesis of 1,3-BDO from 3-HBA under ambient pressure. The catalytic reaction conditions have low equipment requirements and low energy consumption, reducing production costs and operational risks. Attached Figure Description

[0017] Figure 1 The effect of the catalysts prepared in Examples 1-5 and Comparative Examples 1-2 on the hydrogenation of 3-hydroxybutyraldehyde; Figure 2 The effect of different reaction solvents on the hydrogenation of 3-hydroxybutyraldehyde; Figure 3 The effect of different reaction times on the hydrogenation of 3-hydroxybutyraldehyde; Figure 4 The effect of different reaction temperatures on the hydrogenation of 3-hydroxybutyraldehyde; Figure 5 The effect of different catalyst dosages on the hydrogenation of 3-hydroxybutyraldehyde; Figure 6 The XRD characterization spectra of the catalysts prepared in Examples 1, 3-4 and Comparative Examples 1-2 are shown. Detailed Implementation

[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0019] Unless otherwise stated, scientific and technical terms used herein have the meanings commonly understood by those skilled in the art. Unless otherwise specified, the experimental methods used in the examples are conventional methods. Where specific conditions are not specified in the examples, they should be performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0020] Materials and Instrumentation Ni(NO3)2·6H2O, Cu(NO3)2·3H2O, Ca(NO3)2·4H2O, Al(NO3)3·9H2O, ZnCl2, urea, anhydrous ethanol: analytical grade, Tianjin Damao Chemical Reagent Factory; analytical grade, Sinopharm Group Chemical Reagent Factory; acetaldehyde in the experiment was an aqueous solution of acetaldehyde; the water in the experiment was deionized water.

[0021] The preparation process of Zn-Ca-Al solid base catalyst includes the following steps: ZnCl2, Ca(NO3)2·4H2O, and Al(NO3)3·9H2O were mixed and dissolved in deionized water according to a molar ratio of Zn-Ca-Al = 1:3:1. The solution was prepared according to the ratio of (urea):n(NO3) - +Cl - A certain amount of urea was weighed out using a ratio of 1.5:1. The urea and the mixed solution were poured together into a hydrothermal synthesis reactor. After stirring at room temperature for 2 hours, the mixture was placed in an electric heating drying oven and hydrothermally reacted at 120°C for 12 hours. After naturally cooling to room temperature, the precipitate was filtered and repeatedly washed with deionized water until the pH of the filtrate was 7. Then, the surface moisture of the catalyst was removed with anhydrous ethanol. The resulting filter cake was dried at 85°C for 10 hours and then ground into powder. This solid powder was designated as the Zn-Ca-Al-LDH precursor sample. The precursor was placed in a crucible and calcined in a muffle furnace at a heating rate of 5°C / min to 700°C for 3 hours to obtain the Zn-Ca-Al solid base catalyst.

[0022] This invention utilizes 3-hydroxybutyraldehyde prepared by the condensation of acetaldehyde solution using a Zn-Ca-Al solid base catalyst. The specific steps are as follows: Based on an acetaldehyde solution:catalyst ratio of 25:1, a certain amount of catalyst and acetaldehyde solution are placed in an experimental flask. The reaction temperature is controlled at 20°C, and the condensation time is at least 2 hours to prepare 3-hydroxybutyraldehyde. The solution is then analyzed using a gas chromatograph equipped with a flame ionization detector (GC9790H OV-1701 capillary column 30m). The yield of 3-hydroxybutyraldehyde in the solution is recorded. Subsequently, the solid base catalyst in the system is separated by filtration, and the resulting filtrate is the 3-hydroxybutyraldehyde mixed solution.

[0023] Glassware such as glass rods, beakers, and separatory funnels: Tianjin Glass Instruments Co., Ltd.; ME2002E electronic balance: Mettler Toledo Instruments (Shanghai) Co., Ltd.; Standard ground glassware: Tianjin Tianbo Glass Instruments Co., Ltd.; ZRD-7230 electric drying oven: Shanghai Yiheng Scientific Instruments Co., Ltd.; DF-101S constant temperature magnetic stirrer: Shanghai Yukang Science and Education Instrument Equipment Co., Ltd.; 200ml hydrothermal reactor; SHZ-0 circulating water vacuum pump: Gongyi Yuhua Instruments Co., Ltd.; XL-100 rapid intelligent muffle furnace: Hebi Yixin Instruments Co., Ltd.; KQ3200E ultrasonic cleaner: Kunshan Ultrasonic Instruments Co., Ltd.; TH-500 hydrogen generator: Beijing Zhonghuipu Analytical Technology Research Institute.

[0024] Example 1

[0025] A method for preparing a Ni-Cu bimetallic catalyst includes the following steps: S1. Dissolve Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in an appropriate amount of deionized water at a molar ratio of 4:1 (solid-liquid ratio g / L is 7:20) to obtain solution A.

[0026] S2. Calculate the required OH groups for the complete precipitation of metal hydroxides based on the stoichiometric ratio. - The amount of matter, and according to n(OH) - ):n(CO3 2- Given a molar ratio of 2:1, calculate the amounts of NaOH and Na₂CO₃. Dissolve NaOH and Na₂CO₃ in deionized water (solid-liquid ratio g / L is 9.3:40) to obtain solution B.

[0027] S3. Slowly add solution B dropwise into solution A and stir for 2 hours to obtain solution C.

[0028] S4. Place solution C in an electric heating drying oven and hydrothermally react at 120℃ for 12 hours. After it cools naturally to room temperature, take the precipitate and filter it. Wash it repeatedly with deionized water until the pH of the filtrate is 7. Then remove the surface moisture with anhydrous ethanol. Finally, place the filter cake in an oven and dry it at 80℃ for 12 hours. After grinding, a blue-green powder is obtained, which is the first precursor.

[0029] S5. The first precursor is placed in a muffle furnace and calcined at 500°C for 4 hours at a heating rate of 5°C / min to obtain the second precursor powder.

[0030] S6. Place the second precursor powder in a high borosilicate flask. Before reduction, purge the air in the flask with nitrogen gas. Then, continuously purge the flask with H2 generated by a hydrogen generator as the reducing gas. Heat the system from room temperature to 380°C and reduce it at a constant temperature for 2 hours to obtain the Ni-Cu bimetallic catalyst, denoted as T1.

[0031] Example 2

[0032] The Ni-Cu bimetallic catalyst was prepared according to the process provided in Example 1, except that the molar ratio of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in step S1 was 2:1, and the resulting Ni-Cu bimetallic catalyst was denoted as T2.

[0033] Example 3

[0034] The Ni-Cu bimetallic catalyst was prepared according to the process provided in Example 1, except that the molar ratio of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in step S1 was 1:1, and the resulting Ni-Cu bimetallic catalyst was denoted as T3.

[0035] Example 4

[0036] The Ni-Cu bimetallic catalyst was prepared according to the process provided in Example 1, except that the molar ratio of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in step S1 was 1:2, and the resulting Ni-Cu bimetallic catalyst was denoted as T4.

[0037] Example 5

[0038] The Ni-Cu bimetallic catalyst was prepared according to the process provided in Example 1, except that the molar ratio of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in step S1 was 1:4, and the resulting Ni-Cu bimetallic catalyst was denoted as T5.

[0039] Comparative Example 1 The Ni single-metal catalyst was prepared according to the process provided in Example 1, except that Cu(NO3)2·3H2O was not added in step S1. The resulting Ni single-metal catalyst is denoted as D1.

[0040] Comparative Example 2 The Cu single-metal catalyst was prepared according to the process provided in Example 1, except that Ni(NO3)2·6H2O was not added in step S1. The resulting Cu single-metal catalyst was denoted as D2.

[0041] Experimental Example 1: Catalyst Activity Test The atmospheric pressure catalytic hydrogenation reaction of 3-HBA was carried out in a rotor-equipped experimental flask. A spherical condenser was installed at the main neck of the flask to achieve reflux. Cooling water was connected to the lower end of the condenser and discharged from the upper end. The effects of the catalysts prepared in Examples 1-4 and Comparative Examples 1-2 on the atmospheric pressure hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol were investigated. The experimental procedures are as follows: Add 100 mL of ethanol, 1 g of catalyst, and 20 mL of a 3-hydroxybutyraldehyde mixed solution sequentially to the flask. After assembly, perform an airtightness check to ensure the reaction system is leak-free. Then, connect a high-purity hydrogen generator to the flask through a conduit on one side of the neck, with the end of the conduit inserted below the surface of the reaction liquid to ensure sufficient contact between the hydrogen and the reaction system. Connect the end of the conduit to the exhaust gas treatment system. Then, start the condensate circulation system and the hydrogen generator. Next, turn on the heating device to raise the temperature to the set reaction temperature and simultaneously start the magnetic stirrer and adjust the speed. After reacting for a period of time, take a sample of the reaction solution for gas chromatography analysis. Specific reaction conditions: hydrogen flow rate 500 mL / min, reaction temperature 65℃, reaction time 12 h, stirring speed 400 r / min.

[0042] GC analysis conditions: Nitrogen was used as the carrier gas; FID detection was performed; the chromatographic column was a 30 mm × 0.32 mm × 0.50 μm capillary column; detector temperature 250 °C; vaporizer temperature 250 °C; initial column temperature 60 °C, held for 2 min; then increased to 130 °C at a rate of 10 °C / min, held for 5 min; finally increased to 220 °C at a rate of 15 °C / min, held for 5 min. The conversion of 3-HBA and the selectivity of 1,3-BDO were calculated using the area normalization method.

[0043] Table 1 Effect of Ni-Cu ratio on hydrogenation of 3-hydroxybutyraldehyde Catalyst Ni-Cu (molar ratio) 3-HBA conversion (%) 1,3-BDO selectivity (%) Yield (%) T1 4:1 97.88 93.78 91.79 T2 2:1 95.17 70.91 67.48 T3 1:1 57.24 16.85 9.64 T4 1:2 50.08 20.55 10.29 T5 1:4 41.97 18.99 7.97 D1 1:0 97.34 79.04 76.94 D2 0:1 2.55 0 0 Figure 1 Table 1 shows the performance test results of the catalysts prepared in Examples 1-5 and Comparative Examples 1-2. Figure 1As shown, the effect of different Ni / Cu ratios on the reaction was investigated. When no copper was introduced, i.e., the catalyst was Ni-Cu = 1:0, the conversion of 3-HBA was 97.34%, and the selectivity of 1,3-BDO was 79.04%. After introducing an appropriate amount of copper, the conversion of 3-HBA and the selectivity of 1,3-BDO increased significantly. This is because Cu improves the hydrogenation performance of Ni. When Ni-Cu = 4:1, the reaction effect was the best, with a 3-HBA conversion of 97.88% and a 1,3-BDO selectivity of 93.78%. However, with the increase of copper content, the reaction activity gradually became insufficient. When only copper was used as a catalyst in the system, the yield of 1,3-BDO was zero. This is mainly because the dominant role of the active centers in the catalytic system underwent directional migration, and the dominant role of Ni species was gradually replaced by Cu and Cu oxide species. Furthermore, copper's hydrogenation performance at atmospheric pressure is insufficient and it is no longer suitable for this reaction system.

[0044] Experimental Example 2: Effect of Reaction Solvent on Hydrogenation of 3-HBA Using the Ni-Cu bimetallic catalyst T1 prepared in Example 1 as the catalyst, and following the process provided in Experimental Example 1, except that water, ethanol, and methanol were used as the reaction solvents respectively, the effects of different reaction solvents on the hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol were investigated. The results are as follows: Figure 2 As shown in Table 2.

[0045] Table 2 Effect of solvent on hydrogenation of 3-hydroxybutyraldehyde Solvent 3-HBA conversion (%) 1,3-BDO selectivity (%) Yield (%) Water 99.8 35.34 35.27 Ethanol 97.88 93.78 91.79 Methanol 98.63 92.07 90.80 like Figure 2 As shown in Table 2, the effect of the reaction solvent on the hydrogenation of 3-HBA was investigated. The results show that the solvent has a significant impact on the hydrogenation reaction. When water is used as the solvent, although the conversion of 3-HBA is high, the selectivity for 1,3-BDO is very low. This is mainly due to the low solubility of hydrogen in water and the low catalyst activity. Furthermore, the solid base particles dispersed in the solution will further condense 3-hydroxybutyraldehyde into byproducts. Compared to water, methanol and ethanol are more advantageous as solvents for the hydrogenation reaction, with both achieving conversions and selectivities exceeding 90%. This is because hydrogen has high solubility in these two solvents, which reduces mass transfer resistance and allows for the regulation of the interaction between the substrate and the active sites of the catalyst through hydrogen bonding. Simultaneously, their chemical properties are stable, making them less prone to initiating side reactions.

[0046] Experimental Example 3: Effect of Reaction Time on the Hydrogenation of 3-HBA Using the Ni-Cu bimetallic catalyst T1 prepared in Example 1 as the catalyst, and following the process provided in Experimental Example 1, except that the reaction times were 4 h, 6 h, 8 h, 10 h, and 12 h respectively, while the other processes and conditions remained unchanged, the effect of different reaction times on the hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol was investigated. The results are as follows:Figure 3 As shown in Table 3.

[0047] Table 3 Effect of reaction time on hydrogenation of 3-hydroxybutyraldehyde Reaction time (h) 3-HBA conversion (%) 1,3-BDO selectivity (%) Yield (%) 4 84.94 72.65 61.71 6 95.93 90.12 86.45 8 97.37 92.20 89.78 10 97.84 93.69 91.67 12 97.88 93.78 91.79 Performance of Ni-Cu catalysts with different reaction times in the hydrogenation reaction of 3-HBA: Figure 3 As shown in Table 3, the conversion rate of 3-HBA and the selectivity of 1,3-BDO gradually increased with the increase of reaction time. After 10 hours, the growth of both slowed down, and finally at 12 hours, the conversion rate of 3-HBA reached 97.88% and the selectivity of 1,3-BDO reached 93.78%.

[0048] Experimental Example 4: Effect of Reaction Temperature on the Hydrogenation of 3-HBA Using the Ni-Cu bimetallic catalyst T1 prepared in Example 1 as the catalyst, and following the process provided in Experimental Example 1, except that the reaction temperatures were 35℃, 45℃, 55℃, 65℃, and 75℃ respectively, while the other processes and conditions remained unchanged, the effect of different reaction temperatures on the hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol was investigated. The results are as follows: Figure 4 As shown in Table 4.

[0049] Table 4 Effect of temperature on hydrogenation of 3-hydroxybutyraldehyde Reaction temperature (°C) 3-HBA conversion (%) 1,3-BDO selectivity (%) Yield (%) 35 98.09 92.83 91.06 45 98.22 92.60 90.95 55 98.45 93.21 91.77 65 97.88 93.78 91.79 75 98.85 93.28 92.20 The performance of Ni-Cu catalysts in the hydrogenation reaction of 3-HBA at different reaction temperatures is as follows: Figure 4 As shown in Table 4, under mild reaction conditions at 35℃, the conversion rate of 3-HBA reached 98.09%, and the selectivity of the target product 1,3-BDO was 92.83%, indicating that the reaction system possesses excellent catalytic activity and product selectivity even at low temperatures. As the reaction temperature gradually increased from 35℃ to 75℃, the selectivity of 1,3-BDO showed a mild increasing trend, with the yield increasing slowly in tandem. The optimal values ​​were finally achieved at 75℃, where the 3-HBA conversion reached 98.85% and the 1,3-BDO selectivity reached 93.28%, both being the highest values ​​within this temperature range. It is worth noting that when the temperature exceeds 80℃, 3-HBA is prone to dehydration due to thermal instability, leading to the formation of crotonaldehyde, which reduces the effective utilization rate of the raw materials and interferes with the formation of the target product. Therefore, temperatures above 80℃ are not within the suitable process conditions for this study.

[0050] Experimental Example 5: Effect of Catalyst Dosage on Hydrogenation of 3-HBA Using the Ni-Cu bimetallic catalyst T1 prepared in Example 1 as the catalyst, the process provided in Experimental Example 1 was followed, except that the catalyst dosage was 0.4 g, 0.6 g, 0.8 g, 1 g, and 1.2 g, while the other processes and conditions remained unchanged. The effect of different catalyst dosages on the hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol was investigated, and the results are as follows: Figure 5 As shown in Table 5.

[0051] Table 5 Effect of catalyst dosage on hydrogenation of 3-hydroxybutyraldehyde Catalyst loading (g) 3-HBA conversion (%) 1,3-BDO selectivity (%) Yield (%) 0.4 66.74 93.57 62.45 0.6 83.79 91.76 76.89 0.8 91.99 92.89 85.45 1.0 97.88 93.78 91.79 1.2 97.9 93.78 91.81 The performance of Ni-Cu catalysts of different masses on the hydrogenation reaction of 3-HBA is as follows: Figure 5 As shown in Table 5, when the catalyst dosage increased from 0.4 g to 1.0 g, the 3-HBA conversion rapidly increased from 66.74% to 97.88%, and the reaction yield simultaneously increased from 62.45% to 91.79%. However, the selectivity of the target product, 1,3-BDO, showed a characteristic of initially decreasing slightly, then gradually recovering and stabilizing. When the catalyst dosage was further increased to 1.2 g, the 3-HBA conversion (97.9%), the 1,3-BDO selectivity (93.78%), and the reaction yield (91.81%) did not show significant improvement, remaining essentially at levels comparable to those achieved with the 1.0 g dosage. This result indicates that the optimal reaction activity can be achieved with a nickel-copper catalyst dosage of around 1.0 g. Further increasing the catalyst dosage tends to saturate the promoting effect on reaction performance and may also lead to ineffective catalyst consumption.

[0052] Experimental Example 6: Catalyst Characterization Powder X-ray diffraction (XRD) analysis Catalyst physical property and structure analysis was performed using a D8 X-ray diffractometer (XRD) manufactured by Bruker GmbH, Germany, using CuKa rays, with an operating voltage of 40 kV, an operating current of 40 mA, a scanning range of 10–80°, and a scanning speed of 0.2 sec / step.

[0053] The powder X-ray diffraction analysis results of the catalysts prepared in Examples 1, 3-4 and Comparative Example 1 are as follows: Figure 6As shown in the figure, when the Ni-Cu ratio is 1:0, only the characteristic diffraction peaks of Ni appear, with sharp peak shapes and high intensity, indicating that pure Ni has good crystallinity. With the introduction of Ni-Cu, the characteristic diffraction peaks of Cu gradually appear, while the intensity of the Ni diffraction peaks decreases and the peak shape broadens. When the Ni-Cu ratio is 1:2, 1:1, and 4:1, the characteristic diffraction peaks of Ni and Cu coexist, and the relative intensity of the diffraction peaks changes with the ratio of the two, indicating that an interaction occurs between Ni and Cu, forming a Ni-Cu composite structure. Experiments have shown that this interaction affects the hydrogenation performance of 3-HBA, and can improve the selectivity of 1,3-butanediol during the atmospheric pressure hydrogenation of 3-hydroxybutyraldehyde.

[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for preparing a Ni-Cu bimetallic catalyst, characterized in that, Includes the following steps: S1. Dissolve Ni(NO3)2·6H2O and Cu(NO3)2·3H2O in water to obtain solution A; S2. Dissolve NaOH and Na2CO3 in water to obtain solution B; S3. Slowly add solution B to solution A and stir to obtain solution C; S4. Solution C is subjected to a hydrothermal reaction. After the reaction is completed, it is cooled, the precipitate is filtered and washed until neutral, the surface moisture is removed, and then dried and ground to obtain the first precursor. S5. The first precursor is calcined to obtain the second precursor; S6. The second precursor is reduced to obtain a Ni-Cu bimetallic catalyst; The molar ratio of Ni(NO3)2·6H2O to Cu(NO3)2·3H2O is (3~5):

1.

2. The method for preparing the Ni-Cu bimetallic catalyst according to claim 1, characterized in that, In step S1, the molar ratio of Ni(NO3)2·6H2O and Cu(NO3)2·3H2O is 4:

1.

3. The method for preparing the Ni-Cu bimetallic catalyst according to claim 1, characterized in that, In step S2, the molar ratio of NaOH to Na2CO3 is 2:

1.

4. The method for preparing the Ni-Cu bimetallic catalyst according to claim 1, characterized in that, The molar ratio of Ni(NO3)2·6H2O to NaOH is 1:

2.

5. The method for preparing the Ni-Cu bimetallic catalyst according to claim 1, characterized in that, In step S3, the stirring conditions are 25℃ and 50~1500rpm for 2h; in step S4, the hydrothermal reaction conditions are 120℃ for 12h, and the drying conditions are 80℃ for 12h.

6. The method for preparing the Ni-Cu bimetallic catalyst according to claim 1, characterized in that, The calcination conditions were as follows: heating to 500℃ at a rate of 5℃ / min and calcining for 4 hours.

7. The method for preparing the Ni-Cu bimetallic catalyst according to claim 1, characterized in that, In step S6, the second precursor is placed in a reactor, and under a nitrogen atmosphere, H2 is introduced into the reactor and the temperature is raised to 380℃ for a reduction reaction for 2 hours to obtain a Ni-Cu bimetallic catalyst.

8. A Ni-Cu bimetallic catalyst prepared by the method according to any one of claims 1 to 7.

9. The application of the Ni-Cu bimetallic catalyst of claim 8 in the catalytic hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol.

10. The application of the Ni-Cu bimetallic catalyst according to claim 9 in the catalytic hydrogenation of 3-hydroxybutyraldehyde to 1,3-butanediol, characterized in that, The method for preparing 1,3-butanediol by hydrogenation of 3-hydroxybutyraldehyde using a Ni-Cu bimetallic catalyst involves adding the Ni-Cu bimetallic catalyst and 3-hydroxybutyraldehyde in a mass-to-volume ratio (0.4~1.2):20 (g / mL) to an organic solvent and reacting at 35~75℃ for 4~12h under a hydrogen atmosphere; the organic solvent is methanol and / or ethanol.

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