A method for preparing a NiZr alloy catalyst and its application

Abstract

This invention discloses a method for preparing a NiZr alloy catalyst and its application, specifically a catalyst for the selective hydrogenation of succinic anhydride to γ-butyrolactone in a fixed-bed reactor. The catalyst preparation method includes: using Ni(NO3)2·6H2O, Zr(NO3)4·5H2O, and NH4ReO4 as catalyst precursors, preparing a mixture of these nitrate solutions, adding ammonia dropwise to adjust the pH to 11-12, adding a basic silica sol support to the solution, thoroughly stirring and mixing, and then removing ammonia in a water bath to adjust the pH to 6-7. Finally, the prepared NiZr alloy catalyst is dried, calcined, and reduced, then pressed into tablets and sieved to obtain the catalyst. In a fixed-bed reactor, the catalyst of this invention exhibits a succinic anhydride conversion rate greater than 99% and a γ-butyrolactone selectivity greater than 97%. Furthermore, this invention improves the stability of the catalyst and shows promising prospects for industrial applications.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a method for preparing a NiZr alloy catalyst and its application. Background Technology

[0002] Supported metal catalysts are generally composed of active metal nanoparticles and metal oxide supports, typically using noble metals such as gold, platinum, palladium, and ruthenium, or transition metals such as copper and nickel, with two or more as active components. They are nanomaterials with strong catalytic performance. Metal catalysts are widely used in energy, petroleum, chemical, catalysis, and environmental fields. Among them, nickel catalysts can catalyze various coupling reactions, and recent research on nickel-catalyzed reactions has become a hot topic. Nickel is cheaper and more readily available than other noble metals, making it more economical and practical. Due to its low price, lack of toxicity, and high selectivity in activating various chemical substances, metallic Ni is the most promising catalyst to replace noble metals. Therefore, nickel catalysts have many advantages over other catalysts in catalytic reactions and have excellent development prospects. Nickel catalysts can also catalyze cyclic hydrogenation reactions, addition reactions, oxidation reactions, and reduction reactions.

[0003] Gamma-butyrolactone (GBL) is an important fine chemical intermediate that can participate in a variety of chemical reactions due to its unique physicochemical properties. It has significant industrial and socio-economic importance, playing a crucial role in the chemical industry as a versatile chemical. It is not only a highly efficient solvent but also serves as an intermediate in various chemical reactions, used in the synthesis of plastics, fibers, pharmaceuticals, and pesticides. Gamma-butyrolactone can be used to prepare polybutyrolactone (PBL), a biodegradable polymer material that can serve as an environmentally friendly alternative to traditional plastics, helping to reduce plastic pollution and aligning with current trends in sustainable development and green chemistry. Due to its excellent biocompatibility and biodegradability, PBL also has wide applications in the biomedical field, such as in the manufacture of drug delivery systems and tissue engineering scaffolds, contributing to advancements in medical technology. With the increasing global demand for environmentally friendly and sustainable materials, the market demand for gamma-butyrolactone and its derivatives is constantly rising. Producing gamma-butyrolactone helps meet international market demands and enhances international trade competitiveness.

[0004] Therefore, the production of γ-butyrolactone has broad application prospects and significant economic value, while also meeting the requirements of environmental protection and sustainable development. Thus, developing highly active γ-butyrolactone catalysts has considerable economic benefits and promising prospects for industrial application. Summary of the Invention

[0005] This invention provides a method for preparing a NiZr alloy catalyst and its application. The catalyst provided has the characteristics of high reactivity, catalyst stability, and suitability for fixed-bed reactors.

[0006] The technical solution of the present invention: A method for preparing a NiZr alloy catalyst, the method comprising the following steps: (1) Mix the nickel source, zirconium source, rhenium source and solvent, and dissolve them to obtain a clear nitrate liquid mixture; (2) Add ammonia to the nitrate liquid mixture obtained in step (1) to adjust its pH value accordingly; (3) Add the catalyst support alkaline silica sol to the solution, stir thoroughly, and then perform ammonia stripping treatment in a water bath. (4) Drying, calcination and reduction reactions are carried out in sequence, and after pressing and sieving, the NiZr alloy catalyst with rare earth element Re as an additive is obtained.

[0007] Preferably, in step (1), Ni accounts for 5wt%-30wt% of the catalyst.

[0008] Preferably, in step (1), Zr accounts for 2wt%-20wt% of the catalyst.

[0009] Preferably, in step (1), Re accounts for 1wt%-10wt% of the catalyst.

[0010] Preferably, in step (1), the solvent includes one or more of deionized water, ethanol, and acetone.

[0011] Preferably, in step (1), the sieve is a 20-60 mesh sieve.

[0012] Preferably, in step (3), the catalyst support is an alkaline silica sol.

[0013] Preferably, in step (3), ammonia is evaporated in a water bath until the pH reaches 6-7.

[0014] Preferably, in step (4), the calcination temperature is 450-800℃ and the calcination time is 4-12h.

[0015] Preferably, in step (4), the reduction reaction is carried out in a tubular furnace or a fixed bed under an atmosphere of high-purity hydrogen or a hydrogen-nitrogen mixture.

[0016] The Re-modified NiZr alloy catalyst obtained by the catalyst preparation method is used in the selective hydrogenation of succinic anhydride to prepare γ-butyrolactone in a catalytic fixed-bed reactor.

[0017] The present invention has the following beneficial effects: The NiZr bimetallic alloy catalyst described in this invention exhibits interatomic electronic effects due to alloy interactions. These interactions significantly alter the catalyst's properties. Modification with the rare earth element Re further regulates the acid-base properties of the catalyst surface, influencing its surface electronic structure and improving its thermal stability and anti-poisoning performance. It also significantly promotes reaction selectivity and stability. Furthermore, this invention differs from traditional batch autoclave reactors, as it can be conducted in a more efficient fixed-bed reactor with continuous reaction characteristics, showing promising prospects for industrial applications. In this invention, a fixed-bed reactor is used to test the activity of the Re-modified NiZr alloy catalyst. Accurately weighed catalyst is pre-placed in the reactor's isothermal zone and supported with quartz wool. The catalyst bed temperature is measured using a K-type thermocouple. In the fixed-bed reactor, the succinic anhydride conversion is greater than 99%, and the γ-butyrolactone selectivity is greater than 97%. This invention also improves catalyst stability, demonstrating promising prospects for industrial applications. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments. 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 are within the scope of protection of the present invention.

[0019] This invention provides a method for preparing a NiZr alloy catalyst and its application, comprising the following steps: (1) Mix the nickel source, zirconium source, rhenium source and solvent, dissolve them with the corresponding solvent, and stir thoroughly to obtain a clear nitrate liquid mixture; (2) Add an appropriate amount of ammonia to the liquid obtained in step (1) and adjust the pH value to 11-12; (3) Add the catalyst support to the solution, and after thorough stirring, the active metal is fully loaded on the surface of the support. Then, evaporate ammonia in a water bath until the pH reaches 6-7 and then stop. (4) The NiZr alloy catalyst is obtained by sequentially drying, calcining and reducing the active metal, and then pressing and sieving.

[0020] In this invention, the Ni source is one or more of nickel nitrate, nickel sulfate, and nickel chloride. In this invention, the molar concentration of the solution is preferably 0.05–0.9 mol / L, more preferably 0.06–0.5 mol / L, and most preferably 0.15–0.35 mol / L.

[0021] In this invention, the Zr source solution is preferably one or more of zirconium nitrate and zirconium chloride.

[0022] In this invention, the molar concentration of the zirconium source solution is preferably 0.01 to 0.5 mol / L, more preferably 0.03 to 0.3 mol / L, and most preferably 0.05 to 0.2 mol / L.

[0023] After obtaining the mixed solution, the present invention subjectes the solution to drying, calcination, and reduction reactions to obtain the catalyst. The present invention does not impose any particular limitation on the drying method; any drying technique well-known to those skilled in the art can be used. In the present invention, the drying is preferably performed under normal pressure or under vacuum.

[0024] Preferably, the oxide of the catalyst is ground before the reduction reaction. In this invention, after tableting and sieving, the particle size of the catalyst after sieving is preferably 40-60 mesh.

[0025] In this invention, the reduction reaction is preferably carried out under the atmosphere of high-purity hydrogen or a hydrogen-nitrogen mixture. This invention does not impose any particular limitations on the reactor used for the reduction reaction; any reactor well-known to those skilled in the art for carrying out reduction reactions may be used.

[0026] The NiZr bimetallic alloy catalyst of this invention incorporates rare earth metal Re as a modifying agent. This allows for electronic and structural interactions between the atoms of the different metals, which can significantly alter the catalyst's properties, such as activity, selectivity, and stability. In this invention, a fixed-bed reactor is used to test the activity of the Re-modified NiZr alloy catalyst. Accurately weighed catalyst is pre-placed in the isothermal zone of the reactor and supported by silica wool. The catalyst bed temperature is measured using a type K thermocouple.

[0027] The present invention will be further illustrated below through embodiments, but is not limited to these embodiments.

[0028] Example 1 This embodiment relates to a highly efficient NiZr alloy catalyst, its preparation method, and its application in hydrogenation reactions, comprising the following steps: (1) Take two 200mL beakers and weigh out 9.92g Ni(NO3)2·6H2O, 6.35g Zr(NO3)4·5H2O, and 4.25g NH4ReO4 respectively. Mix them with 100mL of ethanol to obtain an ethanol solution of nitrate. After the two solutions are fully dissolved, pour them into the same beaker and stir thoroughly.

[0029] (2) Add 12.35g of alkaline silica sol to the nitrate solution in step (1) and stir at 800 rpm for 1h at room temperature.

[0030] (3) Slowly add ammonia water to the mixed solution in step (2) and use a pH meter to detect the pH value of the solution in real time until 11~12 o'clock to stop adding.

[0031] (4) Place the solution prepared by adjusting with ammonia in step (3) into a water bath and heat it at 50°C until the ammonia evaporates and the pH is about 7. Stop heating the water bath.

[0032] (5) The NiZrReSi mixture obtained in step (4) was dried overnight at 100°C in a vacuum drying oven. Then it was placed in a muffle furnace and calcined at 600°C for 4 hours with a programmed temperature increase of 5°C / min. After calcination, the catalyst was pressed into tablets and sieved to 40~60 mesh.

[0033] (6) The catalyst in oxide state obtained after tableting is placed in a tube furnace and reduced with metallic NiZr at 400°C under pure hydrogen conditions for 4 hours. The final Ni-Zr-Re / SiO2 catalyst is obtained and sealed and stored in a dry environment at 20°C.

[0034] Example 2 The Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that acetone was used as the solvent in the preparation of the catalyst in this example.

[0035] Example 3 A Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that pure water was used as the solvent in the preparation of the catalyst in this example.

[0036] Example 4 A Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that the support used in the preparation of the catalyst in this example is silica aerogel.

[0037] Example 5 The Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that the temperature of ammonia stripping in the water bath during catalyst preparation in this example is 40°C.

[0038] Example 6 The Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that the temperature of ammonia stripping in the water bath during catalyst preparation in this example is 60°C.

[0039] Example 7 A Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that the calcination temperature in the catalyst preparation in this example is 500°C.

[0040] Example 8 A Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that the calcination temperature in the catalyst preparation in this example is 800°C.

[0041] Example 9 The Re-modified Ni-Zr bimetallic alloy catalyst was prepared according to Example 1. The difference from Example 1 is that the reduction of the catalyst in this example was carried out in an atmosphere of 10% hydrogen-nitrogen mixture.

[0042] Example 10 10 g of succinic anhydride was weighed and dissolved in 90 g of 1,4-dioxane solution to prepare a 10% succinic anhydride solution. This solution was used for the hydrogenation reaction. 2 mL of the NiZr-Re / SiO2 catalyst prepared in Example 1 and the reaction substrate were subjected to selective hydrogenation in a fixed bed to obtain the target product γ-butyrolactone.

[0043] The conversion of the reactants was carried out in a fixed-bed reactor at atmospheric pressure. The apparatus was equipped with a heater, temperature-controlled thermocouples, and an online gas chromatograph. The operation was as follows: the catalyst was placed between two layers of silica wool, and the reactants were injected via an injection pump (KDS100, KD Scientific), vaporizing at 200°C before reaching the catalyst bed. The catalyst was reacted in the fixed-bed reactor at a succinic anhydride space velocity of 0.1 h⁻¹. -1 The reaction pressure was at atmospheric pressure, and the reaction temperature was adjusted to 220℃. A 10% succinic anhydride / 1,4-dioxane solution was used as the reaction raw material, and the hydrogenation reaction was carried out with a hydrogen-to-anhydride ratio of 100:1.

[0044] The product was monitored online by gas chromatography (GC-7890, Agilent). Fresh catalyst was used for each experiment. The mass percentage of each component was calculated using the corrected area normalization method. Conversion and product yield were calculated as Molcarbon%. The experimental results are shown in Table 1.

[0045] Comparative Example 1 (1) Take a 200mL beaker, weigh 9.92g Ni(NO3)2·6H2O, 6.35g Zr(NO3)4·5H2O and mix with 100ml ethanol to obtain an ethanol solution of nitrate. (2) Add 12.35g of alkaline silica sol to the nitrate solution in step (1) and stir at 800 rpm for 1h at room temperature.

[0046] (3) Slowly add ammonia water to the mixed solution in step (2) and use a pH meter to detect the pH value of the solution in real time until 11~12 o'clock to stop adding.

[0047] (4) Place the solution prepared by adjusting with ammonia in step (3) into a water bath and heat it at 50°C until the ammonia evaporates and the pH is about 7. Stop heating the water bath.

[0048] (5) The mixture obtained in step (4) was dried overnight at 100°C in a vacuum drying oven. Then it was placed in a muffle furnace and calcined at 600°C for 4 hours with a programmed temperature increase of 5°C / min. After calcination, the catalyst was tableted and sieved to 40-60 mesh.

[0049] (6) The catalyst in oxide state obtained after tableting is placed in a tube furnace and reduced with metallic Ni and Zr at 400°C under pure hydrogen conditions for 4 hours. The final Ni-Zr / SiO2 catalyst without rare earth metal Re modification is obtained. The catalyst is sealed and stored in a dry environment at 20°C.

[0050] Comparative Example 2 (1) Take a 200mL beaker, weigh 9.92g Ni(NO3)2·6H2O and mix it with 100ml ethanol to obtain an ethanol solution of nitrate.

[0051] (2) Add 12.35g of alkaline silica sol to the nitrate solution in step (1) and stir at 800 rpm for 1h at room temperature.

[0052] (3) Slowly add ammonia water to the mixed solution in step (2) and use a pH meter to detect the pH value of the solution in real time until 11~12 o'clock to stop adding.

[0053] (4) Place the solution prepared by adjusting with ammonia in step (3) into a water bath and heat it at 50°C until the ammonia evaporates and the pH is about 7. Stop heating the water bath.

[0054] (5) The NiSi mixture obtained in step (4) was dried overnight at 100°C in a vacuum drying oven. Then it was placed in a muffle furnace and calcined at 600°C for 4 hours with a programmed temperature increase of 5°C / min. After calcination, the catalyst was pressed into tablets and sieved to 40~60 mesh.

[0055] (6) The catalyst in oxide state obtained after tableting is placed in a tube furnace and reduced with metallic Ni at 400°C under pure hydrogen conditions for 4 hours. The final Ni / SiO2 catalyst without Re modification and without Zr is obtained. The catalyst is then sealed and stored in a dry environment at 20°C.

[0056] The catalyst evaluation scheme is shown in Example 10, and the experimental results are shown in Table 1.

[0057] Comparative Example 3 (1) Take a 200mL beaker, weigh 6.35g Zr(NO3)4·5H2O and mix it with 100ml ethanol to obtain an ethanol solution of nitrate. (2) Add 12.35g of alkaline silica sol to the nitrate solution in step (1) and stir at 800 rpm for 1h at room temperature.

[0058] (3) Slowly add ammonia water to the mixed solution in step (2) and use a pH meter to detect the pH value of the solution in real time until 11~12 o'clock to stop adding.

[0059] (4) Place the solution prepared by adjusting with ammonia in step (3) into a water bath and heat it at 50°C until the ammonia evaporates and the pH is about 7. Stop heating the water bath.

[0060] (5) The ZrSi mixture obtained in step (4) was dried overnight at 100°C in a vacuum drying oven. Then it was placed in a muffle furnace and calcined at 600°C for 4 hours with a programmed temperature increase of 5°C / min. After calcination, the catalyst was pressed into tablets and sieved to a mesh size of 40-60.

[0061] (6) The catalyst in oxide state obtained after tableting is placed in a tube furnace and reduced with metallic Zr at 400°C under pure hydrogen conditions for 4 hours. The final Zr / SiO2 catalyst without Re modification and without Ni is obtained. The catalyst is then sealed and stored in a dry environment at 20°C.

[0062] The catalyst evaluation scheme is shown in Example 10, and the experimental results are shown in Table 1. Table 1 Results of the catalyst's performance in the selective hydrogenation of succinic anhydride .

[0063] As shown in Table 1, the Re-modified NiZr bimetallic alloy catalyst of this invention exhibits significantly higher catalytic performance than the unmodified alloy and the Ni-Si or Zr-Si catalysts alone. The modified NiZr bimetallic alloy catalyst achieves a maximum γ-butyrolactone yield of 97%, which is attributed to the electronic and structural interactions between Ni and Zr atoms. During the preparation process, the NiZr catalyst alloys, altering the atomic arrangement and geometry of the catalyst surface. The rare earth element Re can also regulate the acid-base properties of the catalyst surface, affecting its surface electronic structure. When these elements form an alloy, new lattice structures or lattice distortions occur. These changes may introduce new active sites or alter the properties of existing active sites, thereby affecting the catalytic activity and selectivity of the catalyst. As shown in Table 2, in the examples, the Re-modified NiZr bimetallic alloy catalyst did not show a significant decrease in the yield of γ-butyrolactone after 50 h of reaction, indicating that the catalyst has strong stability and the active sites are still maintained after a long reaction time. In contrast, the single metal catalyst is unstable and its activity decreases after a long reaction time. This is due to the fact that the Re-modified NiZr alloy catalyst has better thermal stability and corrosion resistance than the single metal catalyst. This is because alloying can enhance the bonding force between metal atoms, reduce the aggregation or sintering of metal particles under high temperature or harsh environments, and Re improves the thermal stability and anti-poisoning performance of the catalyst, thereby extending the catalyst's service life. The unique properties of the modified alloy catalyst make the catalyst of this invention more valuable for the selective hydrogenation of succinic anhydride to γ-butyrolactone.

[0064] Table 2. Stability of the catalyst in the hydrogenation of succinic anhydride .

[0065] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. The application of a NiZr alloy catalyst in the selective hydrogenation of succinic anhydride to prepare γ-butyrolactone in a catalytic fixed-bed reactor, characterized in that: The preparation method of the NiZr alloy catalyst includes the following steps: (1) The nickel source, zirconium source, rhenium source and solvent are mixed and dissolved to obtain a clear nitrate liquid mixture, wherein Ni accounts for 5wt%~30wt% of the catalyst; Zr accounts for 2wt%~20wt% of the catalyst; and Re accounts for 1wt%~10wt% of the catalyst. (2) Add ammonia to the nitrate liquid mixture obtained in step (1) to adjust the pH value; (3) Add the catalyst support alkaline silica sol to the solution, stir thoroughly, and then perform ammonia stripping treatment in a water bath. (4) The NiZr alloy catalyst is obtained by sequentially drying, calcining and reducing the catalyst, pressing it into tablets and sieving it.

2. The application according to claim 1, characterized in that: In step (1), the solvent includes one or more of deionized water, ethanol, and acetone.

3. The application according to claim 1, characterized in that: In step (2), the pH value is adjusted to 11-12.

4. The application according to claim 1, characterized in that: In step (3), ammonia is evaporated in a water bath until the pH reaches 6-7.

5. The application according to claim 1, characterized in that: In step (4), the calcination temperature is 450~800℃ and the calcination time is 4~12h.

6. The application according to claim 1, characterized in that: In step (4), the reduction reaction is carried out in a tubular furnace or fixed bed under an atmosphere of high-purity hydrogen or a hydrogen-nitrogen mixture.