A raney nickel catalyst, its preparation method and application
Patent Information
- Application Number
- CN202610618444.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-05-07
- Publication Date
- 2026-08-21
AI Technical Summary
[0005]为了克服现有雷尼镍催化剂存在的堆重比高、氢化选择性较差、高温稳定性不佳等问题，本申请提供一种雷尼镍催化剂及其制备方法与应用
1. 本申请提供一种雷尼镍催化剂，其通过引入Cu、Co作为电子促进剂改善活性及氢化选择性，引入Mo与稀土元素改善热稳定性与氢化选择性，并调整Al/(Ni+Cu+Co)用量关系至特定范围，从而获得了一种堆重比低、高温稳定性好、催化性能优异的雷尼镍催化剂。
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Abstract
Description
Technical Field
[0001] This application relates to the field of catalyst technology, specifically to a Raney nickel catalyst, its preparation method, and its application. Background Technology
[0002] Raney nickel, as a classic solid heterogeneous catalyst, is widely used in the catalytic hydrogenation reactions of various unsaturated compounds such as olefins, alkynes, nitriles, and carbonyl compounds due to its high specific surface area and strong hydrogen adsorption capacity.
[0003] In recent years, to further improve the performance of Raney nickel, the industry has mainly focused on adjusting the alloy composition ratio or adding metals such as copper and cobalt as promoters to enhance initial activity. For example, relevant literature reports that introducing copper and cobalt components has increased catalyst activity by approximately 30%. Additionally, some technologies have improved the alkaline leaching process to create a porous structure. However, catalysts obtained through these methods still face several challenges in use: First, the high bulk density of the catalyst leads to high packing density, high bed pressure drop, insufficient exposure of active sites per unit volume in industrial fixed-bed reactors, and poor powder flowability, affecting reaction efficiency and operational convenience. Second, under harsh reaction conditions of high temperature (especially above 100°C) and long-term operation, the catalyst is prone to rapid activity decay due to sintering of active components and collapse of the pore structure, resulting in insufficient high-temperature stability. Third, existing catalysts exhibit poor hydrogenation selectivity, leading to numerous side reactions. These problems collectively restrict the further application of Raney nickel catalysts in efficient and continuous industrial production.
[0004] Therefore, there is an urgent need to develop a Raney nickel catalyst with a low bulk density, good high-temperature stability, and excellent catalytic performance to meet the pressing demand of modern chemical industry for high-performance hydrogenation catalysts. Summary of the Invention
[0005] To overcome the problems of high bulk density, poor hydrogenation selectivity, and poor high-temperature stability of existing Raney nickel catalysts, this application provides a Raney nickel catalyst, its preparation method, and its application.
[0006] In a first aspect, this application provides a Raney nickel catalyst, which adopts the following technical solution: A Raney nickel catalyst comprises the following components in the following proportions: Ni: 45-65%, Al: 30-50%, Cu: 1-5%, Co: 0.5-3%, Mg: 0.1-0.2%, Ca: 0.1-0.2%, Mo: 0.1-1.5%, and rare earth element RE: 0.05%-0.5%; Furthermore, each component satisfies the following relationship: 0.6≤Al / (Ni+Cu+Co)≤0.9.
[0007] This application achieves a Raney nickel catalyst with low bulk density, good high-temperature stability, and excellent catalytic performance by selecting the composition of the nickel-aluminum alloy and controlling the dosage relationship between the components. Specifically, by introducing Cu and Co as electron promoters, this application can form a specific electronic synergistic effect with the main active component Ni, adjusting the adsorption and activation capacity of different unsaturated functional groups on the catalyst surface. In particular, the addition of Cu helps to suppress side reactions such as deep hydrogenation and significantly improves hydrogenation selectivity. The incorporation of Mo and rare earth elements (RE) can improve the thermal stability of the catalyst, effectively suppress the collapse of the pore structure during high-temperature long-term operation, enhance structural integrity, and ensure the continuous and efficient reaction. On the other hand, it can further optimize the electron density of the active center, making the catalyst more selective for the hydrogenation of target unsaturated bonds, and greatly improving the selectivity for converting complex substrates into target products. This application adjusts the Al / (Ni+Cu+Co) ratio to 0.6~0.9, enabling the alloy to contain a sufficient amount of soluble aluminum phase. This ensures that the aluminum is selectively removed during subsequent alkaline leaching activation, thereby forming a rich and interconnected porous nickel framework. In addition, the added trace amounts of Mg and Ca are more readily dissolved during alkaline leaching, which helps to create additional micropores. This significantly reduces the catalyst's bulk density, increases the specific surface area per unit mass of catalyst, and exposes the active sites more fully, making the catalytic reaction more efficient and specific.
[0008] Optionally, the rare earth element is selected from one or more of La, Ce, and Y.
[0009] Optionally, the rare earth element is a mixture of La and Ce.
[0010] Secondly, this application provides a method for preparing a Raney nickel catalyst, comprising the following steps: alloy smelting, crushing and screening, and alkaline leaching activation; The alloy smelting adopts a three-stage smelting process: the first stage temperature is 800-1000℃, and the holding temperature is 20-40 min; the second stage temperature is 1300-1500℃, and the holding temperature is 60-90 min; the third stage temperature is 1100-1200℃, and the holding temperature is 15-25 min. The alkaline leaching activation adopts a two-stage process: the first stage uses a 5-7 wt% NaOH solution at a temperature of 50-70℃ for 2-4 hours; the second stage uses a 10-15 wt% NaOH solution at a temperature of 80-95℃ for 1-2 hours.
[0011] This application provides a method for preparing Raney nickel catalyst. In its three-stage smelting process, firstly, low-melting-point components such as Al and Cu are initially melted and premixed at 800-1000℃; then, high-melting-point metals such as Ni, Co, and Mo are completely melted and uniformly dispersed at 1300-1500℃; finally, the temperature is slowly maintained at 1100-1200℃, so that promoter elements such as Cu and Co, as well as stabilizer elements such as Mo and RE, are uniformly distributed in the nickel-aluminum matrix, forming a specific active center structure, thereby ensuring the high selective hydrogenation of the catalyst. In the two-stage alkaline leaching activation process, a mild treatment is first performed using a low-concentration and low-temperature alkaline solution, which can gently and selectively dissolve the aluminum on the surface and shallow layers of the alloy particles, forming a preliminary pore network and avoiding pore wall collapse caused by excessively vigorous reaction. Then, a high-concentration and high-temperature alkaline solution is used for deep etching, which aims to completely remove the aluminum in the core area and significantly increase the pore size and pore volume. The above-mentioned two-stage alkaline leaching activation process adopts a gradual pore-forming method from the surface to the interior, which can form a three-dimensional porous nickel skeleton with good permeability and high strength, thereby significantly reducing the bulk density of the catalyst and increasing its specific surface area and packing fluidity, thus improving the reaction efficiency and selectivity.
[0012] Optionally, after the third stage of alloy melting is completed, the cooling rate of the system is controlled to be 100-150℃ / h.
[0013] Optionally, the feeding sequence in the alloy smelting step is as follows: first, the alloy components other than aluminum are mixed and smelted in the first stage, then aluminum is added to the system, and then the second and third stages of smelting are carried out in sequence.
[0014] In the alloy smelting step of this application, by further optimizing and adjusting the feeding sequence, the metal components other than aluminum are melted first, and then aluminum is added and melted. This can significantly improve the dispersion uniformity of aluminum in the nickel-aluminum alloy and the structural stability of the nickel-aluminum alloy, so that the aluminum dissolution rate is more consistent during subsequent alkaline leaching. This can effectively avoid local excessive corrosion or insufficient activation, significantly improve the pore structure regularity and catalytic activity of the Raney nickel catalyst, and greatly improve the performance stability and service life of the Raney nickel catalyst.
[0015] Optionally, the two-stage alkaline immersion activation process may include an intermediate treatment: washing with hot water and ultrasonic treatment for 5-10 minutes.
[0016] In the alkaline leaching activation step of this application, after the first stage of alkaline leaching, the alloy particles are first washed with hot water and then subjected to brief ultrasonic treatment, which can effectively loosen and remove aluminum hydroxide in the surface and shallow pores, prevent pore blockage, and facilitate the removal of internal aluminum in the subsequent alkaline leaching process.
[0017] Thirdly, this application provides the application of Raney nickel catalyst in the hydrogenation of unsaturated alcohols or esters to produce the corresponding alcohols or amines.
[0018] In summary, this application has the following beneficial effects: 1. This application provides a Raney nickel catalyst, which improves activity and hydrogenation selectivity by introducing Cu and Co as electron promoters, improves thermal stability and hydrogenation selectivity by introducing Mo and rare earth elements, and adjusts the Al / (Ni+Cu+Co) ratio to a specific range, thereby obtaining a Raney nickel catalyst with low bulk density, good high-temperature stability and excellent catalytic performance.
[0019] 2. The preparation method of the Raney nickel catalyst provided in this application adopts a three-stage smelting process and a two-stage alkaline leaching activation process. The above processes can effectively reduce the bulk density of the catalyst, improve the reaction activity and hydrogenation selectivity of the catalyst, thereby meeting the requirements of modern chemical industry for high-performance hydrogenation catalysts. Detailed Implementation
[0020] This application provides a Raney nickel catalyst comprising the following components in the following proportions: Ni: 45-65%, Al: 30-50%, Cu: 1-5%, Co: 0.5-3%, Mg: 0.1-0.2%, Ca: 0.1-0.2%, Mo: 0.1-1.5%, and rare earth element RE: 0.05%-0.5%; and each component satisfies the following relationship: 0.6 ≤ Al / ( Ni + Cu + Co) ≤ 0.9. The rare earth element is selected from one or more of La, Ce, and Y; further, the rare earth element is a mixture of La and Ce.
[0021] This application also provides a Raney nickel catalyst, the preparation method of which includes the following steps: (1) Alloy smelting: Mix the components of the nickel-aluminum alloy Raney nickel catalyst according to the proportion and add them to a vacuum induction furnace. First, heat the furnace to 800-1000℃ and hold for 20-40 min; then heat the furnace to 1300-1500℃ and hold for 60-90 min; then cool the furnace to 1100-1200℃ and hold for 15-25 min; finally, cool the furnace slowly at a rate of 100-150℃ / h to room temperature to obtain the nickel-aluminum alloy. Furthermore, the feeding sequence is as follows: first, the alloy components other than aluminum are mixed and smelted in the first stage, then aluminum is added to the system, and then the second and third stages of smelting are carried out in sequence.
[0022] (2) Crushing and screening: The smelted nickel-aluminum alloy is crushed and screened to separate nickel-aluminum alloy particles with a particle size of 1-2 mm.
[0023] (3) Alkali leaching activation: Add nickel-aluminum alloy particles to a 50-70℃, 5-7wt% NaOH solution, stir and soak for 2-4 hours, then wash the nickel-aluminum alloy particles with water until neutral, and sonicate for 5-10 minutes; then add the nickel-aluminum alloy particles back to a 10-15wt% NaOH solution at 80-95℃, continue stirring and soaking for 1-2 hours, and after soaking, wash with water until neutral to obtain Raney nickel catalyst.
[0024] The raw materials, reagents, solvents, etc. used in this application can all be obtained commercially.
[0025] The present application will be further described in detail below with reference to embodiments and performance testing. Examples 1-12
[0026] Examples 1-12 each provide a Raney nickel catalyst.
[0027] The difference in the above embodiments is that the alloy composition ratio of the Raney nickel catalyst is shown in Table 1 below.
[0028] The preparation method of the Raney nickel catalyst provided in Examples 1-12 includes the following steps: (1) Alloy smelting: Mix the components according to the alloy content shown in Table 1 and add them to a vacuum induction furnace. First, heat the furnace to 920°C and hold for 30 min; then heat the furnace to 1450°C and hold for 75 min; then cool the furnace to 1150°C and hold for 20 min; finally, cool the furnace slowly at a rate of 120°C / h to room temperature to obtain a nickel-aluminum alloy.
[0029] (2) Crushing and screening: The smelted nickel-aluminum alloy is crushed and screened to separate nickel-aluminum alloy particles with a particle size of 1-2 mm.
[0030] (3) Alkali leaching activation: Add nickel-aluminum alloy particles to a 60℃, 6wt% NaOH solution, stir and soak for 3h, then wash the nickel-aluminum alloy particles with water until neutral, and sonicate for 7min; then add the nickel-aluminum alloy particles back to a 90℃, 13wt% NaOH solution, continue stirring and soaking for 1.5h, after soaking, wash the nickel-aluminum alloy particles with water until neutral to obtain granular Raney nickel catalyst.
[0031] Table 1. Alloy composition ratios of the Raney nickel catalysts provided in Examples 1-12 Example 13
[0032] Example 13 provides a Raney nickel catalyst.
[0033] The difference between the above embodiments and Embodiment 10 is that: (3) the alkaline leaching activation step is as follows: (3) Alkali leaching activation: Add nickel-aluminum alloy particles to a 50℃, 7wt% NaOH solution, stir and soak for 4h, then wash the nickel-aluminum alloy particles with water until neutral, and then sonicate for 10min; then add the nickel-aluminum alloy particles back to an 80℃, 15wt% NaOH solution, continue stirring and soaking for 2h, after soaking, wash the nickel-aluminum alloy particles with water until neutral to obtain granular Raney nickel catalyst. Example 14
[0034] Example 14 provides a Raney nickel catalyst.
[0035] The difference between the above embodiments and Embodiment 10 is that: (3) the alkaline leaching activation step is as follows: (3) Alkali leaching activation: Add nickel-aluminum alloy particles to a 70℃, 5wt% NaOH solution, stir and soak for 2h, then wash the nickel-aluminum alloy particles with water until neutral, and then sonicate for 5min; then add the nickel-aluminum alloy particles back to a 95℃, 10wt% NaOH solution, continue stirring and soaking for 1h, after soaking, wash the nickel-aluminum alloy particles with water until neutral to obtain granular Raney nickel catalyst. Example 15
[0036] Example 15 provides a Raney nickel catalyst.
[0037] The difference between the above embodiments and Embodiment 10 is that: (3) no ultrasonic treatment was performed in the alkaline leaching activation step, as follows: (3) Alkali leaching activation: Add nickel-aluminum alloy particles to a 60℃, 6wt% NaOH solution, stir and soak for 3h, then wash the nickel-aluminum alloy particles with water until neutral; then add the nickel-aluminum alloy particles back to a 90℃, 13wt% NaOH solution, continue stirring and soaking for 1.5h, after soaking, wash the nickel-aluminum alloy particles with water until neutral to obtain granular Raney nickel catalyst. Example 16
[0038] Example 16 provides a Raney nickel catalyst.
[0039] The difference between the above embodiments and Embodiment 10 is that: (1) the cooling rate in the alloy smelting step is 100℃ / h. Example 17
[0040] Example 17 provides a Raney nickel catalyst.
[0041] The difference between the above embodiment and embodiment 10 is that: (1) the cooling rate in the alloy melting step is 150℃ / h. Example 18
[0042] Example 18 provides a Raney nickel catalyst.
[0043] The difference between the above embodiments and Embodiment 10 is that: (1) the cooling rate in the alloy smelting step is 200℃ / h. Example 19
[0044] Example 19 provides a Raney nickel catalyst.
[0045] The difference between the above embodiment and Embodiment 10 lies in the order of material feeding in the alloy smelting step, as follows: (1) Alloy smelting: Mix all components except aluminum according to the alloy content shown in Example 10 in Table 1, and add them to a vacuum induction furnace. First, heat to 920°C and hold for 30 min. Then, add aluminum to the system and heat to 1450°C and hold for 75 min. Then, cool to 1150°C and hold for 20 min. Finally, slowly cool down at a rate of 120°C / h to room temperature to obtain a nickel-aluminum alloy. Comparative Examples 1-4
[0046] Comparative Examples 1-4 each provide a Raney nickel catalyst.
[0047] The difference in the above comparisons lies in the alloy composition ratio of the Raney nickel catalyst, as shown in Table 1. Comparative Example 5
[0048] Comparative Example 5 provides a Raney nickel catalyst.
[0049] The difference between the above comparative example and Example 2 is that: (1) the alloy smelting steps are as follows: (1) Alloy smelting: Mix the components of the nickel-aluminum alloy according to the proportion and add them into a vacuum induction furnace. Heat the furnace to 1450℃ and hold for 105 min. Then cool the furnace to 1150℃ and hold for 20 min. Finally, cool the furnace slowly at a rate of 120℃ / h to room temperature to obtain the nickel-aluminum alloy. Comparative Example 6
[0050] Comparative Example 6 provides a Raney nickel catalyst.
[0051] The difference between the above comparative example and Example 2 is that: (3) the alkaline leaching activation step is as follows: (3) Alkali leaching activation: Add nickel-aluminum alloy particles to a 90℃, 10wt% NaOH solution, stir and soak for 4h. After soaking, wash the nickel-aluminum alloy particles with water until neutral to obtain granular Raney nickel catalyst. Performance testing
[0052] 1. The bulk density of the Raney nickel catalysts obtained in Examples 1-19 and Comparative Examples 1-6 was tested, and the results are shown in Table 2 below.
[0053] 2. Based on the Raney nickel catalysts obtained in Examples 1-19 and Comparative Examples 1-6, a fixed-bed reactor was used to carry out the hydrogenation of 1,4-butynediol (BYD) to prepare 1,4-butanediol (BDO); wherein the mass fraction of BYD in the BYD aqueous solution was 35 wt%, the pH of the 1,4-butynediol aqueous solution was 5.5, and the weight hourly space velocity of the 1,4-butynediol aqueous solution was 1.0 h⁻¹. -1 The molar ratio of hydrogen to 1,4-butynediol in the aqueous solution was 3:1. The hydrogenation reaction temperature was 125°C, the reaction pressure was 28 MPa, and the catalyst loading was 100 g. The results of the catalytic hydrogenation reactions of the Raney nickel catalysts in Examples 1-18 and Comparative Examples 1-6 are shown in Table 2 below.
[0054] Table 2. Bulk density ratio and catalytic effect of Raney nickel catalysts obtained in Examples 1-19 and Comparative Examples 1-6
[0055] According to the test results in Table 2 above, the Raney nickel catalysts obtained in Examples 1-19 have a bulk density of 1.28-1.39 g / mL, a BYD conversion rate of 99.3-100%, and a BDO selectivity of 97.3-99.8%. This indicates that the cost ratio of the nickel-aluminum alloy provided in this application is reasonable, and it can be used to prepare Raney nickel catalysts with low bulk density, good hydrogenation selectivity, good high-temperature stability, and excellent catalytic performance.
[0056] The Raney nickel catalyst obtained by the nickel-aluminum alloy of Comparative Example 1 had a bulk density as high as 1.61 g / mL. After catalytic hydrogenation, the BYD conversion rate was only 90.2% and the BDO selectivity was only 87.3%.
[0057] The Raney nickel catalyst obtained by the component ratio of nickel-aluminum alloy in Comparative Example 2 has a low bulk density but poor catalytic performance. After catalytic hydrogenation, the BYD conversion rate is only 84.7% and the BDO selectivity is only 76.5%.
[0058] The nickel-aluminum alloy of Comparative Example 3, without the addition of Mo and rare earth elements, resulted in a Raney nickel catalyst with slightly lower catalytic efficiency and hydrogenation selectivity. After catalytic hydrogenation, the BYD conversion rate was only 95.9% and the BDO selectivity was only 92.6%.
[0059] In Comparative Example 4, the nickel-aluminum alloy without the addition of Mg and Ca had a Raney nickel catalyst with a bulk density as high as 1.48 g / mL. After catalytic hydrogenation, the BYD conversion rate was only 97.2% and the BDO selectivity was only 94.8%.
[0060] The alloy smelting step of Comparative Example 5 adopted a two-stage smelting process. The catalytic efficiency and hydrogenation selectivity of the obtained Raney nickel catalyst were slightly worse. After catalytic hydrogenation reaction, the BYD conversion rate was 98.2% and the BDO selectivity was 96.7%.
[0061] Comparative Example 6 uses a one-stage alkaline leaching process, and the resulting Raney nickel catalyst has a bulk density as high as 1.54 g / mL. After catalytic hydrogenation, the BYD conversion rate is only 91.4% and the BDO selectivity is only 90.3%.
[0062] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.
Claims
1. A Raney nickel catalyst, characterized in that, The components include the following content: Ni: 45-65%, Al: 30-50%, Cu: 1-5%, Co: 0.5-3%, Mg: 0.1-0.2%, Ca: 0.1-0.2%, Mo: 0.1-1.5%, and rare earth elements (RE): 0.05%-0.5%. Furthermore, each component satisfies the following relationship: 0.6≤Al / (Ni+Cu+Co)≤0.
9.
2. The Raney nickel catalyst according to claim 1, characterized in that, The rare earth element is selected from one or more of La, Ce and Y.
3. The Raney nickel catalyst according to claim 1, characterized in that, The rare earth element is a mixture of La and Ce.
4. The method for preparing the Raney nickel catalyst according to any one of claims 1-3, characterized in that, Includes the following steps: Alloy smelting, crushing and screening, and alkaline leaching activation; The alloy smelting adopts a three-stage smelting process: the first stage temperature is 800-1000℃, and the holding temperature is 20-40 min; the second stage temperature is 1300-1500℃, and the holding temperature is 60-90 min; the third stage temperature is 1100-1200℃, and the holding temperature is 15-25 min. The alkaline leaching activation adopts a two-stage process: the first stage uses a 5-7 wt% NaOH solution at a temperature of 50-70℃ for 2-4 hours; the second stage uses a 10-15 wt% NaOH solution at a temperature of 80-95℃ for 1-2 hours.
5. The method for preparing the Raney nickel catalyst according to claim 4, characterized in that, After the third stage of alloy melting is completed, the cooling rate of the system is controlled at 100-150℃ / h.
6. The method for preparing the Raney nickel catalyst according to claim 4, characterized in that, The feeding sequence in the alloy smelting step is as follows: first, the alloy components other than aluminum are mixed and smelted in the first stage; then, aluminum is added to the system, and then the second and third stages of smelting are carried out in sequence.
7. The method for preparing the Raney nickel catalyst according to claim 4, characterized in that, The two-stage alkaline leaching activation process includes an intermediate treatment: washing with hot water and ultrasonic treatment for 5-10 minutes.
8. The application of the Raney nickel catalyst as described in claim 4 in the hydrogenation of unsaturated alcohols or esters to produce the corresponding alcohols or amines.