A method for preparing a bimetallic supported catalyst

Abstract

This invention discloses a method for preparing a bimetallic supported catalyst, belonging to the field of catalyst preparation technology. The invention involves synthesizing a copolymer with terminal active Br, followed by a nucleophilic substitution reaction of the terminal Br with sodium acetylacetonate to introduce an acetylacetonate chelating group at the copolymer end, obtaining a template agent with both structure-directing and metal-chelating functions. This template agent is then compounded with P123 and reacted with a sodium silicate solution and a Cu-containing... 2+ Ni 2+ A metal solution is co-assembled in a single pot, utilizing the chelating and anchoring effect of the terminal acetylacetone group of the template agent on the metal ions, thereby pre-anchoring the metal ions at the micelle interface. The catalyst is then prepared through hydrothermal reaction, calcination, and reduction. The catalyst prepared by this invention has the advantages of good metal dispersibility, strong anti-sintering ability, and high mass transfer efficiency, and can be applied to the reaction of furfural hydrogenation to furfuryl alcohol.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically a method for preparing a bimetallic supported catalyst. Background Technology

[0002] Furfural is an important biomass platform compound, and its catalytic hydrogenation to furfuryl alcohol is a key reaction for the high-value utilization of biomass resources. Currently, the industrial hydrogenation of furfural to furfuryl alcohol mainly uses copper-chromium catalysts. However, chromium in these catalysts is highly toxic, and spent catalysts cause serious environmental pollution. Furthermore, traditional copper-chromium catalysts also face problems such as loss of active components and difficulty in separation and regeneration during the reaction. Therefore, developing environmentally friendly chromium-free copper-based catalysts has become an important research direction in this field.

[0003] Impregnation is one of the most widely used methods for preparing chromium-free copper-based catalysts. However, catalysts prepared by impregnation have significant technical drawbacks: 1. The metal particles are uneven in size and poorly dispersed, and the interaction force between them and the support is weak, making it easy for the active components to agglomerate and sinter during the reaction; 2. The catalysts synthesized by impregnation have low metal atom utilization and the active components are easily lost, which seriously affects the catalyst's cycle life and industrial application prospects.

[0004] In summary, to address the aforementioned problems, this invention proposes a method for preparing a bimetallic supported catalyst. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a bimetallic supported catalyst to solve the related technical problems existing in the prior art.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by the present invention is as follows: A method for preparing a bimetallic supported catalyst includes the following steps: (1) Add bromopolyethylene glycol (PEG-Br), styrene, N,N,N',N',N''-pentamethyldiethylenetriamine (PMDETA) to a solvent, add cuprous bromide under a nitrogen atmosphere, react at 50-60℃ for 6-8h, precipitate, wash and dry to obtain copolymer; (2) Add the copolymer to the solvent, then add sodium acetylacetonate and phase transfer catalyst, react at 60-70℃ for 10-15h, precipitate, wash and dry to obtain template agent; (3) Add the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (P123) and template agent to hydrochloric acid solution and stir for 15-30 min; add sodium silicate solution, then adjust the pH to 6.5-7.5 and stir for 15-30 min to obtain gel; add metal solution dropwise, stir for 15-30 min, then adjust the pH to 9-10 and continue stirring for 2-3 h, carry out hydrothermal reaction, filter, wash, dry, calcinate and reduce to obtain catalyst.

[0007] In a more optimized manner, in step (1), the molar ratio of PEG-Br, styrene, PMDETA, and cuprous bromide is 1:(30-40):(1-1.5):(1-1.5). The volume ratio of styrene to solvent is 1:(1-3); The solvent used is tetrahydrofuran (THF).

[0008] In a more optimized manner, in step (2), the mass ratio of copolymer to sodium acetylacetonate is 1:(0.03-0.05). The mass ratio of copolymer to phase transfer catalyst is 1:(0.03-0.05); The phase transfer catalyst used is tetrabutylammonium bromide; The ratio of copolymer to solvent is 1g:(10-20)mL; The solvent used is N,N-dimethylformamide or dimethyl sulfoxide.

[0009] In a more optimized manner, in step (3), the mass ratio of P123 to the template agent is (2-3):1; P123, the ratio of hydrochloric acid solution is 1g: (30-40)mL; The concentration of the hydrochloric acid solution is 8-12 mmol / L.

[0010] Ideally, the concentration of the sodium silicate solution is 1-1.5 mol / L, and the solvent is deionized water. The metal solution comprises the following components: 100-150 g / L copper nitrate trihydrate and 100-150 g / L nickel nitrate hexahydrate; The mass ratio of polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer, sodium silicate, copper nitrate trihydrate, and nickel nitrate hexahydrate is 1:(2-3):(0.5-1). The mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate is 1:1.

[0011] In a more optimized manner, the hydrothermal reaction conditions in step (3) are: hydrothermal reaction for 18-24 hours in a closed environment at 120-130°C; The calcination process conditions are as follows: heat to 540-560℃ at a heating rate of 1-2℃ / min, and calcin for 4-6 hours; The reduction process conditions are: reduction at 600-650℃ in a hydrogen atmosphere for 2-3 hours.

[0012] In a more optimized manner, in step (3), a sulfuric acid solution with a concentration of 1-1.5 mol / L and a concentrated ammonia solution with a concentration of 25-28 wt% are used to adjust the pH.

[0013] The application of a bimetallic supported catalyst prepared by a method for preparing a catalyst in the hydrogenation of furfural to furfuryl alcohol.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention synthesizes a PEG-PS-Br copolymer with active Br at the ends through atom transfer radical polymerization (ATRP), and then introduces an acetylacetone chelating group at the ends of the copolymer by utilizing the nucleophilic substitution reaction of the terminal Br with sodium acetylacetone, thus obtaining a template agent with both structure-directing and metal-chelating functions; the acetylacetone group at the ends of this template agent can chelate Cu in the sol-gel stage. 2+ Ni 2+ Loading is achieved through subsequent metal-support interactions and the physical confinement of mesoporous channels; the acetylacetone group at the end of the template agent interacts with Cu. 2+ The chelation effect helps to achieve pre-dispersion of metals at the micelle interface. Combined with the confinement effect of mesoporous channels, highly dispersed copper oxide and nickel oxide mixed oxides are generated in the channels during calcination. During reduction, metal NiCu is formed. The dual effects of chelation pre-dispersion and channel confinement can significantly reduce the grain size of oxide precursors, limit the size of metal particles after reduction, effectively inhibit metal sintering and agglomeration, and significantly improve the utilization rate of metal atoms and hydrogenation catalytic activity.

[0015] 2. This invention uses P123 and a template agent as a composite template agent to prepare a catalyst via a self-assembly method. P123 induces phase separation in the sol-gel process, forming interconnected macroporous channels, and also self-assembles into micelles, which, after calcination removal, form mesopores. The addition of the template agent further enriches the size distribution of the micelles, forming a mixed micelle system with P123. By adjusting the ratio of P123 to the template agent, the pore size of the mesopores can be flexibly controlled. The macropores provide low-resistance diffusion paths for reactant and product molecules, effectively eliminating internal diffusion limitations in liquid-phase reactions, while the mesopores provide high-density anchoring sites and physical confinement spaces for the metal active components. The synergistic effect of these two mechanisms enables reactant molecules to quickly reach active sites and product molecules to diffuse away promptly, effectively suppressing side reactions caused by material backmixing and significantly improving catalytic selectivity and production efficiency.

[0016] 3. This invention employs a one-pot co-assembly strategy of composite template agent, sodium silicate solution, and metal solution. The composite template agent plays a dual role in structure guidance and metal pre-anchoring during the sol stage. After hydrothermal reaction, calcination, and reduction, the metal is directly generated in situ on the inner wall of the pores, forming highly dispersed NiCu metal. Compared with the traditional two-step method of first preparing the carrier and then impregnating the metal, this invention simplifies the preparation process and avoids metal agglomeration caused by capillary forces in the impregnation method. At the same time, through the combination of P123 and the template agent, a multi-level pore structure of macropores and mesopores is achieved, which has the dual advantages of mass transfer efficiency and confined stability. Detailed Implementation

[0017] The technical solutions in the embodiments of the present invention are clearly and completely described below. Obviously, the embodiments described are only some, not all, implementations of the present invention. Other implementations that can be obtained by those skilled in the art based on the embodiments of the present invention without creative effort all fall within the protection scope of the present invention.

[0018] In the following examples, the average molecular weight of PEG-Br was 1000, and the degree of Br substitution was 95%; the average molecular weight of P123 was 5800, and the block ratio was EO. 20 PO 70 EO 20 The silica is of type GCL20, with a particle size of 15nm and a specific surface area of ​​200m². 2 / g; all other raw materials are commercially available.

[0019] The pH was adjusted using a 1.2 mol / L sulfuric acid solution and a 26 wt% concentrated ammonia solution.

[0020] Example 1: A method for preparing a bimetallic supported catalyst, comprising the following steps: (1) PEG-Br, styrene, and PMDETA were added to tetrahydrofuran. Cuprous bromide was added under nitrogen atmosphere protection. The reaction was carried out at 55°C for 7 h. After precipitation, washing, and drying, a copolymer was obtained. The molar ratio of PEG-Br, styrene, PMDETA, and cuprous bromide was 1:35:1.2:1.2. The volume ratio of styrene to tetrahydrofuran was 1:2. (2) The copolymer was added to N,N-dimethylformamide, and then sodium acetylacetonate and tetrabutylammonium bromide were added. The mixture was reacted at 65°C for 12 h, and the product was precipitated, washed and dried to obtain the template agent. The mass ratio of copolymer, sodium acetylacetonate and tetrabutylammonium bromide was 1:0.04:0.04; the ratio of copolymer to N,N-dimethylformamide was 1 g:15 mL. (3) Add P123 and template agent to a 10 mmol / L hydrochloric acid solution and stir for 20 min; add sodium silicate solution, then adjust the pH to 7 and stir for 20 min; add metal solution dropwise and stir for 20 min; then adjust the pH to 9.5 and continue stirring for 2.5 h; then perform hydrothermal reaction at 125 °C in a closed environment for 20 h; filter, wash, and dry; then heat to 550 °C at a heating rate of 1.5 °C / min and calcine for 5 h; then calcine in a hydrogen atmosphere at 62 °C. The catalyst was obtained by reduction at 0℃ for 2.5 h; the mass ratio of P123 to template agent was 2.5:1; the ratio of P123 to hydrochloric acid solution was 1 g: 35 mL; the mass ratio of P123, sodium silicate, and copper nitrate trihydrate was 1:2.5:0.4; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate was 1:1; the concentration of sodium silicate solution was 1.2 mol / L, and the solvent was deionized water; the metal solution included the following components: 130 g / L copper nitrate trihydrate and 130 g / L nickel nitrate hexahydrate.

[0021] Example 2: A method for preparing a bimetallic supported catalyst, comprising the following steps: (1) PEG-Br, styrene, and PMDETA were added to tetrahydrofuran. Cuprous bromide was added under nitrogen atmosphere protection. The reaction was carried out at 50°C for 8 hours. After precipitation, washing, and drying, a copolymer was obtained. The molar ratio of PEG-Br, styrene, PMDETA, and cuprous bromide was 1:30:1:1. The volume ratio of styrene to tetrahydrofuran was 1:1. (2) The copolymer was added to N,N-dimethylformamide, and then sodium acetylacetonate and tetrabutylammonium bromide were added. The mixture was reacted at 60°C for 15 h, and the product was precipitated, washed and dried to obtain the template agent. The mass ratio of copolymer, sodium acetylacetonate and tetrabutylammonium bromide was 1:0.03:0.03; the ratio of copolymer to N,N-dimethylformamide was 1 g:10 mL. (3) Add P123 and template agent to an 8 mmol / L hydrochloric acid solution and stir for 15 min; add sodium silicate solution, then adjust the pH to 6.5 and stir for 15 min; add metal solution dropwise, stir for 15 min, then adjust the pH to 9 and continue stirring for 2 h; then perform hydrothermal reaction in a closed environment at 120 °C for 24 h; filter, wash, and dry; heat to 540 °C at a heating rate of 1 °C / min and calcine for 6 h; then calcine in a hydrogen atmosphere at 60 °C. The catalyst was obtained by reduction at 0℃ for 3 hours; the mass ratio of P123 to template agent was 2:1; the ratio of P123 to hydrochloric acid solution was 1g:30mL; the mass ratio of P123, sodium silicate, and copper nitrate trihydrate was 1:2:0.3; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate was 1:1; the concentration of sodium silicate solution was 1mol / L, and the solvent was deionized water; the metal solution included the following components: 100g / L copper nitrate trihydrate and 100g / L nickel nitrate hexahydrate.

[0022] Example 3: A method for preparing a bimetallic supported catalyst, comprising the following steps: (1) PEG-Br, styrene, and PMDETA were added to tetrahydrofuran. Cuprous bromide was added under nitrogen atmosphere protection. The reaction was carried out at 60°C for 6 hours. After precipitation, washing, and drying, a copolymer was obtained. The molar ratio of PEG-Br, styrene, PMDETA, and cuprous bromide was 1:40:1.5:1.5. The volume ratio of styrene to tetrahydrofuran was 1:3. (2) The copolymer was added to N,N-dimethylformamide, and then sodium acetylacetonate and tetrabutylammonium bromide were added. The mixture was reacted at 70°C for 10 h, and the product was precipitated, washed and dried to obtain the template agent. The mass ratio of copolymer, sodium acetylacetonate and tetrabutylammonium bromide was 1:0.05:0.05; the ratio of copolymer to N,N-dimethylformamide was 1 g:20 mL. (3) Add P123 and template agent to a 12 mmol / L hydrochloric acid solution and stir for 30 min; add sodium silicate solution, then adjust the pH to 7.5 and stir for 30 min; add metal solution dropwise, stir for 30 min, then adjust the pH to 10 and continue stirring for 3 h; then perform hydrothermal reaction in a closed environment at 120 °C for 18 h; filter, wash, and dry; heat to 560 °C at a heating rate of 2 °C / min and calcine for 4 h; then calcine in a hydrogen atmosphere at 65 °C. The catalyst was obtained by reduction at 0℃ for 2 hours; the mass ratio of P123 to template agent was 3:1; the ratio of P123 to hydrochloric acid solution was 1g:40mL; the mass ratio of P123, sodium silicate, and copper nitrate trihydrate was 1:3:0.5; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate was 1:1; the concentration of sodium silicate solution was 1.5mol / L, and the solvent was deionized water; the metal solution included the following components: 150g / L copper nitrate trihydrate and 150g / L nickel nitrate hexahydrate.

[0023] Comparative Example 1: Based on Example 2, the template agent was replaced with an equal mass of P123, including the following steps: P123 was added to an 8 mmol / L hydrochloric acid solution and stirred for 15 min; sodium silicate solution was added, and the pH was adjusted to 6.5, and stirred for 15 min; metal solution was added dropwise, and stirred for 15 min; then the pH was adjusted to 9, and stirring was continued for 2 h; then the reaction was carried out hydrothermally at 120 °C in a closed environment for 24 h; the mixture was filtered, washed, and dried, and then calcined at 540 °C at a heating rate of 1 °C / min for 6 h; finally, the mixture was reduced at 600 °C for 3 h in a hydrogen atmosphere to obtain the catalyst. The ratio of P123 to hydrochloric acid solution is 1.5g:30mL; the mass ratio of P123, sodium silicate, and copper nitrate trihydrate is 1.5:2:0.3; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate is 1:1; the concentration of sodium silicate solution is 1mol / L, and the solvent is deionized water; the metal solution includes the following components: 100g / L copper nitrate trihydrate and 100g / L nickel nitrate hexahydrate.

[0024] Comparative Example 2: Based on Example 2, P123 was replaced with an equal mass of template agent, including the following steps: (1) PEG-Br, styrene, and PMDETA were added to tetrahydrofuran. Cuprous bromide was added under nitrogen atmosphere protection. The reaction was carried out at 50°C for 8 hours. After precipitation, washing, and drying, a copolymer was obtained. The molar ratio of PEG-Br, styrene, PMDETA, and cuprous bromide was 1:30:1:1. The volume ratio of styrene to tetrahydrofuran was 1:1. (2) The copolymer was added to N,N-dimethylformamide, and then sodium acetylacetonate and tetrabutylammonium bromide were added. The mixture was reacted at 60°C for 15 h, and the product was precipitated, washed and dried to obtain the template agent. The mass ratio of copolymer, sodium acetylacetonate and tetrabutylammonium bromide was 1:0.03:0.03; the ratio of copolymer to N,N-dimethylformamide was 1 g:10 mL. (3) Add the template agent to a 10 mmol / L hydrochloric acid solution and stir for 15 min; add sodium silicate solution, then adjust the pH to 6.5 and stir for 15 min; add metal solution dropwise, stir for 15 min, then adjust the pH to 9 and continue stirring for 2 h; then perform hydrothermal reaction at 120 °C in a closed environment for 24 h; filter, wash, and dry; heat to 540 °C at a heating rate of 1 °C / min and calcine for 6 h; reduce at 600 °C in a hydrogen atmosphere for 3 h to obtain the catalyst; the ratio of template agent to hydrochloric acid solution is 1.5 g: 30 mL; the mass ratio of template agent, sodium silicate, and copper nitrate trihydrate is 1.5: 2: 0.3; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate is 1: 1; the concentration of sodium silicate solution is 1 mol / L, and the solvent is deionized water; the metal solution includes the following components: 100 g / L copper nitrate trihydrate and 100 g / L nickel nitrate hexahydrate.

[0025] Comparative Example 3: Based on Example 2, the template agent was adjusted to use a copolymer as the template agent, including the following steps: (1) PEG-Br, styrene, and PMDETA were added to tetrahydrofuran. Cuprous bromide was added under nitrogen atmosphere protection. The reaction was carried out at 50°C for 8 hours. After precipitation, washing, and drying, a copolymer was obtained. The molar ratio of PEG-Br, styrene, PMDETA, and cuprous bromide was 1:30:1:1. The volume ratio of styrene to tetrahydrofuran was 1:1. (2) P123 and the copolymer were added to an 8 mmol / L hydrochloric acid solution and stirred for 15 min; sodium silicate solution was added, and the pH was adjusted to 6.5 and stirred for 15 min; metal solution was added dropwise and stirred for 15 min, and the pH was adjusted to 9 and stirred for 2 h. Then, the mixture was hydrothermally reacted at 120 °C in a closed environment for 24 h; the mixture was filtered, washed, and dried, and then heated to 540 °C at a heating rate of 1 °C / min and calcined for 6 h; the mixture was then calcined in a hydrogen atmosphere at 60 °C. The catalyst was obtained by reduction at 0℃ for 3 hours; the mass ratio of P123 to copolymer was 2:1; the ratio of P123 to hydrochloric acid solution was 1g:30mL; the mass ratio of P123, sodium silicate, and copper nitrate trihydrate was 1:2:0.3; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate was 1:1; the concentration of sodium silicate solution was 1mol / L, and the solvent was deionized water; the metal solution included the following components: 100g / L copper nitrate trihydrate and 100g / L nickel nitrate hexahydrate.

[0026] Comparative Example 4: Based on Example 2, a catalyst was prepared using an impregnation method, comprising the following steps: (1) PEG-Br, styrene, and PMDETA were added to tetrahydrofuran. Cuprous bromide was added under nitrogen atmosphere protection. The reaction was carried out at 50°C for 8 hours. After precipitation, washing, and drying, a copolymer was obtained. The mass ratio of PEG-Br, styrene, PMDETA, and cuprous bromide was 1:30:1:1. The volume ratio of styrene to tetrahydrofuran was 1:1. (2) The copolymer was added to N,N-dimethylformamide, and then sodium acetylacetonate and tetrabutylammonium bromide were added. The mixture was reacted at 60°C for 15 h, and the product was precipitated, washed and dried to obtain the template agent. The mass ratio of copolymer, sodium acetylacetonate and tetrabutylammonium bromide was 1:0.03:0.03; the ratio of copolymer to N,N-dimethylformamide was 1 g:10 mL. (3) Add P123 and template agent to hydrochloric acid solution with a concentration of 8 mmol / L and stir for 15 min; add sodium silicate solution, then adjust pH to 6.5, stir for 15 min, and then hydrothermally react for 24 h in a closed environment at 120 °C; filter, wash, dry, heat to 540 °C at a heating rate of 1 °C / min, and calcine for 6 h to obtain silica support; the mass ratio of P123 to template agent is 2:1; the ratio of P123 to hydrochloric acid solution is 1 g: 30 mL; the mass ratio of P123 to sodium silicate is 1:2; the concentration of sodium silicate solution is 1 mol / L, and the solvent is deionized water; (4) The metal solution was added to the silica support, stirred and mixed, and then allowed to stand for 8 hours. It was then dried and heated to 540°C at a heating rate of 1°C / min and calcined for 6 hours. The catalyst was obtained by reducing it for 3 hours under a hydrogen atmosphere at 600°C. The mass ratio of silica support, copper nitrate trihydrate and nickel nitrate hexahydrate was 3:0.3. The mass ratio of copper nitrate trihydrate and nickel nitrate hexahydrate was 1:1. The metal solution included the following components: 100 g / L copper nitrate trihydrate and 100 g / L nickel nitrate hexahydrate.

[0027] Comparative Example 5: Based on Example 2, a catalyst was prepared using silica as a support via an impregnation method, comprising the following steps: The metal solution was added to silica, stirred and mixed, then allowed to stand for 8 hours and dried. The temperature was increased to 540℃ at a rate of 1℃ / min and calcined for 6 hours. The catalyst was then reduced at 600℃ for 3 hours under a hydrogen atmosphere to obtain the catalyst. The mass ratio of silica, copper nitrate trihydrate, and nickel nitrate hexahydrate was 3:0.3; the mass ratio of copper nitrate trihydrate to nickel nitrate hexahydrate was 1:1. The metal solution consisted of the following components: 100 g / L copper nitrate trihydrate and 100 g / L nickel nitrate hexahydrate.

[0028] Performance testing: Furfural conversion rate and furfuryl alcohol selectivity test: The catalysts prepared in the examples and comparative examples were used as samples. 0.05 g of sample, 10 mL of isopropanol and 1 mmol of furfural were added to the reaction vessel in sequence. After sealing, the air in the vessel was replaced with nitrogen. After reacting for 1 h at a pressure of 0.5 MPa, a temperature of 140 °C and a rotation speed of 600 r / min, the reaction solution was taken and the furfural conversion rate and furfuryl alcohol selectivity were analyzed by gas chromatography. Stability and cycle life test: 0.05 g sample, 10 mL isopropanol and 1 mmol furfural were added to the reaction vessel in sequence. After sealing, the air inside the vessel was replaced with nitrogen. The reaction was carried out for 1 h at a pressure of 0.5 MPa, a temperature of 140 °C and a rotation speed of 600 r / min. After the reaction, the sample was collected by magnetic separation. After washing with isopropanol, it was directly used for the next furfural hydrogenation reaction. The furfural conversion rate and furfural alcohol selectivity of the sample used for furfural hydrogenation reaction were tested after 10 uses.

[0029]

[0030] The catalysts prepared in Examples 1-3 exhibit excellent catalytic performance. First, through a nucleophilic substitution reaction, an acetylacetone chelating group is introduced into the end of the template agent molecule, endowing the template agent with the chemical ability to capture metal ions. Through the synergistic combination of P123 and the functionalized template agent, a dual-channel structure with both macropores and mesopores is constructed. This effectively solves the technical problems of poor metal dispersion, easy agglomeration and sintering, low mass transfer efficiency, and insufficient cycle stability in the prior art, and significantly improves the activity, selectivity, and industrial application prospects of the catalyst.

[0031] Comparative Example 1, based on Example 2, replaced the template agent with an equal mass of P123. Its initial furfural conversion rate and furfuryl alcohol selectivity were significantly lower than those of Example 2, and its activity decreased significantly after repeated use. This indicates that P123 cannot anchor metal ions in the sol-gel stage, resulting in poor metal dispersibility and easy aggregation and inactivation. This verifies the important role of the acetylacetone chelating group at the end of the template agent in the chelation and anchoring of metal ions.

[0032] Comparative Example 2, based on Example 2, replaced P123 with an equal mass of template agent. Its initial furfural conversion rate and furfuryl alcohol selectivity were significantly lower than those of Example 2, and its activity decreased significantly after recycling. This indicates that a single template agent cannot form a carrier with a regular mesoporous structure, resulting in insufficient specific surface area and pore structure, and poor dispersion of active sites. This verifies the synergistic effect of the combination of P123 and the template agent as a composite template agent in this invention.

[0033] Comparative Example 3, based on Example 2, adjusted the template agent by using a copolymer instead of an acetylacetone group. The initial furfural conversion rate and furfuryl alcohol selectivity were significantly lower than those of Example 2, and the activity decreased significantly after recycling. This indicates that when the template agent does not contain an acetylacetone chelating group at the end, metal ions are only physically adsorbed and loaded onto the carrier surface, and cannot form a stable chemical anchor. This verifies the importance of introducing an acetylacetone group in this invention.

[0034] Comparative Example 4, based on Example 2, uses an impregnation method to prepare a catalyst. Its initial furfural conversion rate and furfuryl alcohol selectivity are significantly lower than those of Example 2, and its activity decreases significantly after recycling. This indicates that the traditional impregnation method causes severe metal agglomeration due to capillary forces, weak metal-support interaction, and easy sintering and loss of active components, thus verifying the superiority of the preparation method of the present invention over the traditional impregnation method.

[0035] Comparative Example 5, based on Example 2, uses silica as a support and prepares the catalyst by impregnation. Its initial furfural conversion rate and furfuryl alcohol selectivity are significantly lower than those of Example 2, and its activity decreases significantly after recycling. This indicates that ordinary silica support lacks a dual-channel structure of macropores and mesopores, resulting in low mass transfer efficiency and weak anchoring ability of active sites. This verifies the advantages of the support of the present invention in improving metal dispersion and mass transfer efficiency.

[0036] It will be apparent to those skilled in the art that the present invention is not limited to the specific details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit and core features of the invention. Therefore, the above embodiments should be considered exemplary rather than restrictive in any respect. The scope of protection of the present invention is defined by the appended claims, not by the foregoing description, and is therefore intended to encompass all variations in the meaning and scope of the equivalents of the claims within the scope of the present invention.

Claims

1. A method for preparing a bimetallic supported catalyst, characterized in that: Includes the following steps: (1) Brominated polyethylene glycol, styrene, N,N,N',N',N''-pentamethyldiethylenetriamine were added to a solvent, and cuprous bromide was added under a nitrogen atmosphere to carry out an atom transfer radical polymerization reaction to obtain a copolymer; (2) The copolymer is added to a solvent, and then sodium acetylacetonate and a phase transfer catalyst are added to carry out a nucleophilic substitution reaction to obtain a template agent; (3) Add the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer and the template agent to the hydrochloric acid solution and stir; Add sodium silicate solution to carry out hydrolysis-condensation reaction to obtain gel; A metal solution is added dropwise, followed by chelation, hydrothermal reaction, calcination, and reduction to obtain a catalyst.

2. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: In step (1), the molar ratio of brominated polyethylene glycol, styrene, N,N,N',N',N''-pentamethyldiethylenetriamine and cuprous bromide is 1:(30-40):(1-1.5):(1-1.5).

3. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: In step (2), the mass ratio of the copolymer to sodium acetylacetonate is 1:(0.03-0.05). The mass ratio of the copolymer to the phase transfer catalyst is 1:(0.03-0.05).

4. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: In step (3), the mass ratio of the polyethylene oxide-polypropylene oxide-polyethylene oxide triblock copolymer to the template agent is (2-3):1; The concentration of the hydrochloric acid solution is 8-12 mmol / L; The ratio of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer to hydrochloric acid solution is 1g:(30-40)mL.

5. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: The metal solution comprises the following components: 100-150 g / L copper nitrate trihydrate and 100-150 g / L nickel nitrate hexahydrate.

6. The method for preparing a bimetallic supported catalyst according to claim 4, characterized in that: The mass ratio of the poly(ethylene oxide-poly(propylene oxide-poly(ethylene oxide)) triblock copolymer, sodium silicate, and copper nitrate trihydrate is 1:(2-3):(0.5-1).

7. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: In step (1), the process conditions for the atom transfer radical polymerization reaction are: reaction temperature 50-60℃ and reaction time 6-8h.

8. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: In step (2), the process conditions for the nucleophilic substitution reaction are: reaction temperature 60-70℃ and reaction time 10-15h.

9. The method for preparing a bimetallic supported catalyst according to claim 1, characterized in that: In step (3), the process conditions for the chelation reaction are: stirring for 15-30 min, then adjusting the pH to 9-10, and continuing to stir for 2-3 h; The hydrothermal reaction process conditions are: hydrothermal reaction for 18-24 hours in a closed environment at 120-130℃; The calcination process conditions are as follows: heating to 540-560℃ at a heating rate of 1-2℃ / min, and calcining for 4-6 hours; The reduction process conditions are: reduction at 600-650℃ in a hydrogen atmosphere for 2-3 hours.

10. The application of the catalyst prepared by the method according to any one of claims 1-9 in the reaction of furfural hydrogenation to furfuryl alcohol.

Images