A nickel porphyrin carbon-based catalyst, a preparation method and application thereof

Abstract

The application provides a nickel porphyrin carbon-based catalyst and a preparation method and application thereof, and the preparation method comprises the following steps: (1) mixing a metal salt, a first metal organic ligand, a second organic ligand and an organic solvent, and then performing a crystallization reaction to obtain a three-dimensional nickel porphyrin-based catalyst precursor; the first metal organic ligand comprises a nickel tetracarboxyphenyl porphyrin; (2) performing calcination on the three-dimensional nickel porphyrin-based catalyst precursor in step (1) to obtain the nickel porphyrin carbon-based catalyst. The nickel porphyrin carbon-based catalyst with a three-dimensional MOF as a precursor is prepared through coordination bonds between NiTCPP and metal nodes and the introduction of a second organic ligand, the catalyst pore size is adjustable and controllable, and the activity and stability of the catalyst are improved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of coordination polymer derived carbon materials, and particularly relates to a nickel porphyrin carbon-based catalyst and a preparation method and application thereof. BACKGROUND

[0002] At present, nickel-based carbon material catalysts are widely used in various hydrogenation reactions, such as phenol hydrogenation to prepare cyclohexanone, unsaturated dimer acid hydrogenation to prepare hydrogenated dimer acid, isooctene aldehyde hydrogenation to prepare 2-ethylhexyl aldehyde, etc. Succinic anhydride (SAA) is an important chemical intermediate, which can be prepared by hydrogenation of maleic anhydride. Catalyzing maleic anhydride to prepare succinic anhydride under mild reaction conditions with high stability and high activity has high development potential in the field of green, low-carbon and sustainable chemistry. For a long time, scientific researchers have been committed to developing heterogeneous catalysts with high activity, high selectivity and high stability. Due to different strategies and methods used, the effects achieved are not the same.

[0003] M. Krebsz et al. used styrene-based cation exchange resin as a carrier, bonded nickel ions with imino diacetate functional groups therein, carbonized the resin material in a nitrogen atmosphere at 500-1000℃ to obtain nickel nanoparticles and carbon microsphere materials, and catalyzed the reduction of 4-nitrophenol to 4-aminophenol in the presence of sodium borohydride, which showed good activity and stability.

[0004] Q.C. Zhang et al. used commercial Cu-MOFs as a substrate, after carbonization and etching, loaded ultrafine platinum nanoparticles and amorphous nickel on the three-dimensional mesoporous framework thereof; compared with commercial Pt / C catalyst, the catalyst showed excellent performance in methanol oxidation and nitrophenol reduction, and exhibited different selectivity to 2 / 3 / 4-nitrophenol.

[0005] CN111036214A discloses a preparation method and application of a Ni-CNT catalyst for hydrogenated dimer acid production. Organic nickel, carbon source and additive are mixed in proportion to obtain a nickel-carbon-based catalyst precursor, which is passivated by inert gas and reduced by reducing gas, and shows good dimer acid conversion rate and service life in the reaction of hydrogenating unsaturated dimer acid to produce hydrogenated dimer acid.

[0006] Although various strategies have been proposed in the prior art, the nickel-based carbon material prepared by traditional carbon material impregnation of nickel still has the following problems to be solved: (1) the problem of easy falling off of the loaded active metal, resulting in poor stability of the catalyst; (2) part of the active metal elements is wrapped inside the carbon material and single metal is used as the active center, resulting in low raw material conversion rate and product selectivity; (3) the pore size of the catalyst carrier is too small, the diffusion of the substrate in the pore is limited, resulting in low raw material conversion rate.

[0007] Coordination Polymers, abbreviated as CPs, are coordination entities with intramolecular porosity and repeating 1, 2 and 3 dimensional extensions formed by self-assembly of organic ligands and metal ions or clusters through coordination bonds. In recent years, three-dimensional coordination polymers, metal-organic frameworks (MOFs), an important member of the CPs family, have become self-sacrificial templates and precursors for the preparation of carbon-based nanomaterials due to their rich metal / organic components, adjustable structure and pore size, high specific surface area (BET), large pore volume and customizable morphology. Through effective post-processing, especially high-temperature calcination, the organic ligands can be converted into heteroatom-doped carbon, and the metal ions or clusters can be converted into metal single atoms or nanoparticles (NPs) uniformly dispersed in the carbon matrix. In addition, the cavities on the MOFs pre-anchored with metals can prevent the formed metal single atoms or nanoparticles from aggregating. Based on the rapid development of MOFs materials, MOFs-derived carbon-based materials (metal / metal oxide-modified carbon-based materials, doped carbon materials) have a wide range of applications in heterogeneous catalysis, such as oxidation, hydrogenation, dehydrogenation, bio-oil refining, Fischer-Tropsch synthesis, electrocatalysis (hydrogen evolution, oxygen evolution), etc.

[0008] Therefore, it is an urgent problem for those skilled in the art to develop a new type of MOFs-derived carbon-based material with adjustable pore size, high stability and excellent catalytic performance. SUMMARY

[0009] The purpose of the present application is to provide a nickel porphyrin carbon-based catalyst and its preparation method and application. By the coordination bond between nickel tetracarboxyphenyl porphyrin (NiTCPP) and metal nodes and the introduction of a second organic ligand, a nickel porphyrin carbon-based catalyst with three-dimensional MOFs as a precursor is prepared, which realizes the adjustable and controllable pore size of the catalyst and improves the activity and stability of the catalyst.

[0010] To achieve the purpose of the present application, the following technical solutions are adopted:

[0011] In a first aspect, the present application provides a preparation method of a nickel porphyrin carbon-based catalyst, which comprises:

[0012] (1) mixing metal salt, first metal organic ligand, second organic ligand and organic solvent, and then performing crystallization reaction to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0013] The first metal organic ligand comprises nickel tetracarboxyphenyl porphyrin;

[0014] (2) calcining the three-dimensional nickel porphyrin-based catalyst precursor of step (1) to obtain the nickel porphyrin carbon-based catalyst.

[0015] The preparation method of the application selects NiTCPP and adds metal salt and a second organic ligand to prepare a three-dimensional MOFs skeleton precursor, and then a calcination step is performed to obtain a nickel porphyrin carbon-based catalyst with high catalytic activity and excellent catalytic stability.

[0016] In the application, NiTCPP is used as an active metal organic ligand, and after carbonization and reduction, the Ni-N bond enhances the chelation of the active metal on the carrier, reduces the loss of the active metal, and improves the stability of the catalyst.

[0017] In the application, the coordination bond between NiTCPP and the metal salt node is based on the porphyrin central metal nickel and the metal node, which not only gives the catalyst two active centers to improve the activity of the catalyst, but also inhibits the problem of easy shedding of the loaded active metal, strengthens the stability of the catalyst, and through reasonable regulation of the distance between the active metals, the product selectivity and raw material conversion rate of the catalyst are improved by using the synergistic effect.

[0018] In the application, the second organic ligand is introduced to change the distance between the layers, realize the adjustable and controllable catalyst pore size, improve the internal diffusion rate of the substrate, and improve the catalytic activity of the catalyst.

[0019] As a preferred technical solution of the application, the molar ratio of the metal salt and the first metal organic ligand in step (1) is (1-1.2):(2-5), for example, it can be 1:2.5, 1:3, 1.05:3, 1.1:3.5, 1.15:4 or 1.15:4.5, etc., but it is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0020] It is worth noting that by controlling the molar ratio of the metal salt and the first metal organic ligand in the range of (1-1.2):(2-5), the crystallinity of the MOFs material can be reasonably regulated, which is beneficial to improve the raw material conversion rate and product selectivity.

[0021] Preferably, the molar ratio of the first metal organic ligand and the second organic ligand in step (1) is (2-5):(1-3), for example, it can be 2.5:1.5, 3:1.5, 3.5:2, 3.5:3 or 4:3, etc., but it is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0022] It is worth noting that by controlling the molar ratio of the first metal organic ligand and the second organic ligand in the range of (2-5):(1-3), the required MOFs structure can be synthesized directionally, the generation of other structure MOFs is reduced, which is beneficial to improve the raw material conversion rate and product selectivity.

[0023] Preferably, the molar ratio of the metal salt to the organic solvent in step (1) is (1-1.2):(10-85), for example, it can be 1:30, 1:60, 1.05:35, 1.1:45, 1.15:70 or 1.15:80, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable.

[0024] As a preferred technical solution of the present application, the metal salt in step (1) includes any one of zinc nitrate, cobalt nitrate, copper nitrate, nickel nitrate, magnesium nitrate or calcium nitrate or a combination of at least two thereof, wherein a typical but non-limiting combination is a combination of zinc nitrate and cobalt nitrate, a combination of copper nitrate and nickel nitrate or a combination of magnesium nitrate and calcium nitrate, etc., and preferably nickel nitrate or copper nitrate.

[0025] In the present application, when zinc nitrate is selected as the raw material of the metal salt, metal zinc is beneficial to the hydrogenation of C=O, resulting in a lower product selectivity than metal nickel or metal copper.

[0026] Preferably, the second organic ligand in step (1) includes any one of pyrazine (pz), 2,2'-bipyridine (2-bpy), 4,4'-bipyridine (4-bpy), 2,2'-dimethyl-4,4'-bipyridine (dmbpy), 1,2-bis(4-pyridyl)ethylene (bpee), trans-1,2-bis(4-pyridyl)diazene (bpza) or 3,6-di-4-pyridyl-1,2,4,5-tetrazine (bpt) or a combination of at least two thereof, wherein a typical but non-limiting combination is a combination of pz and 2-bpy, a combination of 4-bpy and dmbpy or a combination of bpee and bpza, etc., and preferably pyrazine or 4,4'-bipyridine.

[0027] Preferably, the organic solvent in step (1) includes any one of N,N-diethylformamide (DEF), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA) or ethanol or a combination of at least two thereof, and preferably N,N-dimethylformamide.

[0028] In the present application, if the organic solvent is selected as DMF, DEF or DMA, the molar ratio of the metal salt to the organic solvent is preferably (1-1.2):(10-67); if the organic solvent contains ethanol, the molar ratio of the metal salt to the organic solvent is preferably (1-1.2):(10-85).

[0029] As a preferred technical solution of the present application, the mixed solution after mixing in step (1) is placed in a reaction kettle.

[0030] In the present application, the inner lining material of the reaction kettle is polytetrafluoroethylene.

[0031] Preferably, the volume ratio of the mixed solution to the reactor is (0.1-0.75):1, for example, it can be 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1 or 0.7:1, etc., but not limited to the listed values, other values not listed in the above value range are also applicable, preferably (0.3-0.6):1.

[0032] As a preferred technical solution of the present application, the temperature of the crystallization reaction in step (1) is 70-200℃, for example, it can be 80℃, 90℃, 100℃, 110℃, 120℃, 130℃, 140℃, 150℃, 160℃, 170℃, 180℃ or 190℃, etc., but not limited to the listed values, other values not listed in the above value range are also applicable, preferably 90-140℃.

[0033] In the present application, by controlling the crystallization reaction temperature in the range of 70-200℃, if the crystallization reaction temperature is too low, the reaction of organic ligand and metal node is not complete, the catalyst structure has defects, resulting in the decline of the catalytic performance of the catalyst; if the crystallization reaction temperature is too high, the reaction of organic ligand and metal node is too fast, the catalyst has poor crystallinity, resulting in the decline of the catalytic performance of the catalyst.

[0034] Preferably, the crystallization reaction in step (1) is carried out for 6-72h, for example, it can be 10h, 15h, 20h, 25h, 30h, 35h, 40h, 45h, 50h, 55h, 60h, 65h or 70h, etc., but not limited to the listed values, other values not listed in the above value range are also applicable, preferably 12-36h.

[0035] Preferably, after the crystallization reaction in step (1), the reaction solution is cooled to room temperature, and then filtration, washing and drying are sequentially carried out.

[0036] In the present application, the cooling time is 5-24h, for example, it can be 7h, 9h, 10h, 12h, 14h, 15h, 16h, 18h, 20h or 22h, etc., but not limited to the listed values, other values not listed in the above value range are also applicable, preferably 8-12h.

[0037] In the present application, the temperature of the room temperature is 20-30℃, for example, it can be 21℃, 22℃, 23℃, 24℃, 25℃, 26℃, 27℃, 28℃ or 29℃, etc., but not limited to the listed values, other values not listed in the above value range are also applicable.

[0038] Preferably, the washing includes washing with an organic solvent until the filtrate is colorless, and then washing with ethanol for 3-5 times.

[0039] In the present application, the total amount of the ethanol washing is 30-50 mL.

[0040] Preferably, the drying comprises vacuum drying, and the temperature of the drying is 25-90℃, such as 30℃, 40℃, 50℃, 60℃, 70℃ or 80℃, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable, preferably 40-70℃.

[0041] In the present application, the drying time is 10-14h, such as 10.5h, 11h, 11.5h, 12h, 12.5h, 13h or 13.5h, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable.

[0042] As a preferred technical solution of the present application, before the calcination of step (2), the inert gas is introduced into the tube furnace, and the air is discharged.

[0043] Preferably, the calcination of step (2) is carried out in a tube furnace with an inert gas atmosphere.

[0044] Preferably, the inert gas comprises any one or a combination of at least two of nitrogen, argon or helium, and a typical but non-limiting combination is a combination of nitrogen and argon, a combination of argon and helium, or a combination of nitrogen, argon and helium, etc.

[0045] Preferably, the flow rate of the introduced inert gas is 10-100 mL / min, such as 20 mL / min, 30 mL / min, 40 mL / min, 50 mL / min, 60 mL / min, 70 mL / min, 80 mL / min or 90 mL / min, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable, preferably 30-60 mL / min.

[0046] As a preferred technical solution of the present application, the heating time of the calcination of step (2) is 2-11h, such as 3h, 4h, 5h, 6h, 7h, 8h, 9h or 10h, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable, preferably 3-5h.

[0047] Preferably, the final temperature of the calcination of step (2) is 300-1100℃, such as 400℃, 500℃, 600℃, 700℃, 800℃, 900℃ or 1000℃, etc., but not only limited to the listed values, other values not listed in the above value range are also applicable, preferably 500-800℃.

[0048] Preferably, the holding time of the roasting in step (2) is 2-12 h, for example, it can be 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h or 11 h, etc., but is not limited to the listed values, and other values not listed in the above value range are also applicable, and preferably 6-8 h.

[0049] Preferably, the roasting in step (2) is followed by furnace cooling to room temperature.

[0050] As a preferred technical solution of the present application, the preparation method comprises:

[0051] (1) mixing metal salts, a first metal organic ligand, a second organic ligand and an organic solvent in a molar ratio of (1-1.2):(2-5):(1-3):(10-85), then placing the mixture in a reaction kettle, and then performing a crystallization reaction at 70-200℃ for 6-72 h, cooling the reaction liquid to room temperature, and then sequentially performing suction filtration, washing and drying to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0052] The metal salt comprises any one or a combination of at least two of zinc nitrate, cobalt nitrate, copper nitrate, nickel nitrate, magnesium nitrate or calcium nitrate; the first metal organic ligand comprises nickel tetracarboxyphenyl porphyrin; and the second organic ligand comprises any one or a combination of at least two of pyrazine, 2,2'-bipyridine, 4,4'-bipyridine, 2,2'-dimethyl-4,4'-bipyridine, 1,2-di(4-pyridyl)ethylene, trans-1,2-di(4-pyridyl)diazene or 3,6-di-4-pyridyl-1,2,4,5-tetrazine;

[0053] (2) placing the three-dimensional nickel porphyrin-based catalyst precursor in step (1) in a tube furnace, then introducing an inert gas with a flow rate of 10-100 mL / min into the tube furnace to discharge air, and then performing roasting in an inert gas atmosphere by heating to 300-1100℃ for 2-11 h and holding for 2-12 h, and then furnace cooling to room temperature to obtain the nickel porphyrin carbon-based catalyst.

[0054] In a second aspect, the present application provides a nickel porphyrin carbon-based catalyst prepared by the preparation method of the first aspect.

[0055] The nickel porphyrin carbon-based catalyst has a three-dimensional pore structure.

[0056] The specific surface area of the nickel porphyrin carbon-based catalyst is ≥330 m 2 / g, for example, it can be 340 m 2 / g, 350 m 2 / g, 370 m 2 / g, 400 m 2 / g, 450 m2 / g, 500 m 2 / g or 600 m 2 / g, etc., but not limited to the listed values, and other values not listed within the above-mentioned value range are also applicable.

[0057] The pore size of the nickel porphyrin carbon-based catalyst is regulated by changing the type of the second organic ligand.

[0058] The present application realizes adjustable and controllable catalyst pore size by changing the type of the second organic ligand, and the stability of the carbon-based material catalyst surface and framework can be adjusted by using different metal nodes, further improving the stability and product selectivity of the catalyst; using three-dimensional MOFs as the precursor of the carbon-based material catalyst, the carbon-based material catalyst has a high specific surface area, a uniform and adjustable porous structure, easily accessible single-atom active metal centers, and excellent catalytic activity.

[0059] In a third aspect, the present application provides an application of the nickel porphyrin carbon-based catalyst of the second aspect, wherein the nickel porphyrin carbon-based catalyst is used for hydrogenation reaction, preferably maleic anhydride hydrogenation reaction.

[0060] The nickel porphyrin carbon-based catalyst of the present application can be well applied to hydrogenation reaction, and is especially suitable for maleic anhydride hydrogenation reaction.

[0061] The numerical range of the present application includes not only the listed point values, but also any point values between the above-mentioned numerical range that are not listed, and the specific point values included in the range are not listed due to the length and for the sake of simplicity.

[0062] Compared with the prior art, the present application has the following beneficial effects:

[0063] (1) The preparation method provided by the present application uses the coordination bond between NiTCPP and metal nodes and introduces a second organic ligand to prepare a three-dimensional MOF precursor, and then calcines to prepare a catalyst, solving the problem of easy falling off of the loaded active metal, improving the internal diffusion rate of the substrate, and at the same time inhibiting the agglomeration of the active metal in the calcination process, realizing single-atom catalysis;

[0064] (2) The nickel porphyrin carbon-based catalyst provided by the present application regulates the pore size of the nickel porphyrin carbon-based catalyst by changing the type of the metal salt or the second organic ligand, and uses the synergistic effect of different layers of active metal to improve the catalytic performance and stability;

[0065] (3) The nickel porphyrin carbon-based catalyst provided by the application has a conversion rate of maleic anhydride of 96.24% or higher and a selectivity of succinic anhydride product of 95.27% or higher when used in the hydrogenation reaction of maleic anhydride; meanwhile, the nickel porphyrin carbon-based catalyst has excellent stability and cycle performance, and the conversion rate of maleic anhydride is still 95.12% or higher and the selectivity of succinic anhydride product is still 93.28% or higher after 30 cycles. BRIEF DESCRIPTION OF DRAWINGS

[0066] Figure 1 The nitrogen adsorption curve of the nickel porphyrin carbon-based catalyst prepared for Example 1, Example 2 and Comparative Example 1 of the application;

[0067] In the figure, the solid line represents the nitrogen adsorption process, and the dashed line represents the nitrogen desorption process.

[0068] Figure 2 The pore size distribution curve of the nickel porphyrin carbon-based catalyst prepared for Example 1, Example 2 of the application;

[0069] Figure 3 The pore size distribution curve of the nickel porphyrin carbon-based catalyst prepared for Example 1, Example 3 of the application;

[0070] Figure 4 The pore size distribution curve of the nickel porphyrin carbon-based catalyst prepared for Example 1, Example 7 of the application. DETAILED DESCRIPTION

[0071] The technical solutions of the application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the application and should not be regarded as specific limitations on the application.

[0072] Example 1

[0073] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0074] (1) 2.9 g of nickel nitrate, 18.6 g of NiTCPP, 1.8 g of pz and 50 mL of DMF are mixed and uniformly stirred, then the mixed solution is placed in a 100 mL reaction kettle with a polytetrafluoroethylene liner, and then static crystallization reaction is carried out at 120℃ for 36 h, the reaction liquid is cooled to room temperature within 12 h, then suction filtration is carried out, DMF is used for washing until the filtrate is colorless, then ethanol is used for washing for 3 times (10 mL each time), and finally the product is placed in a vacuum drying box and dried at 70℃ for 12 h to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0075] (2) The three-dimensional nickel porphyrin-based catalyst precursor of step (1) is placed in a tube furnace, then nitrogen gas with a flow rate of 50 mL / min is continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature is raised to 800°C in a nitrogen atmosphere for 8h and kept for 8h, and then the furnace is cooled to room temperature, to obtain a Ni-Ni-1 carbon-based catalyst (the Ni content is 9.8% tested based on the catalyst), denoted as catalyst A.

[0076] Example 2

[0077] The present embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, which comprises:

[0078] (1) 3.5 g of nickel nitrate, 46.5 g of NiTCPP, 1.7 g of 4-bpy and 40 mL of DEF are mixed and stirred uniformly, then the mixture is placed in a 100 mL reaction kettle with a polytetrafluoroethylene liner, then static crystallization reaction is carried out at 200°C for 36h, the reaction liquid is cooled to room temperature within 24h, then suction filtration is carried out, washed with DEF until the filtrate is colorless, then washed with ethanol for 5 times (10 mL each time), and finally placed in a vacuum drying oven for drying at 90°C for 12h, to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0079] (2) The three-dimensional nickel porphyrin-based catalyst precursor of step (1) is placed in a tube furnace, then nitrogen gas with a flow rate of 100 mL / min is continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature is raised to 800°C in a nitrogen atmosphere for 8h and kept for 8h, and then the furnace is cooled to room temperature, to obtain a Ni-Ni-2 carbon-based catalyst (the Ni content is 8.2% tested based on the catalyst), denoted as catalyst B.

[0080] Example 3

[0081] The present embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, which comprises:

[0082] (1) 1.8 g of cobalt nitrate, 27.9 g of NiTCPP, 1.6 g of bpt and 50 mL of DEF are mixed and stirred uniformly, then the mixture is placed in a 100 mL reaction kettle with a polytetrafluoroethylene liner, then static crystallization reaction is carried out at 180°C for 72h, the reaction liquid is cooled to room temperature within 18h, then suction filtration is carried out, washed with DEF until the filtrate is colorless, then washed with ethanol for 5 times (10 mL each time), and finally placed in a vacuum drying oven for drying at 80°C for 12h, to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0083] (2) The three-dimensional nickel porphyrin-based catalyst precursor prepared in step (1) was placed in a tube furnace, then nitrogen gas with a flow rate of 60 mL / min was continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature was raised to 1100°C in a nitrogen atmosphere for 11 h and kept for 2 h, and then the furnace was cooled to room temperature, to obtain a Co-Ni carbon-based catalyst (the content of Ni was 6.6% and the content of Co was 1.2% as tested based on the catalyst), which was recorded as catalyst C.

[0084] Example 4

[0085] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0086] (1) 2.4 g of copper nitrate, 18.6 g of NiTCPP, 1.7 g of 4-bpy and 50 mL of ethanol were mixed and stirred uniformly, then the mixture was placed in a 100 mL reaction kettle with a polytetrafluoroethylene lining, and then static crystallization reaction was carried out at 70°C for 6 h, the reaction liquid was cooled to room temperature within 5 h, then suction filtration was performed, washing with DMF until the filtrate was colorless, washing with ethanol for 5 times (10 mL each time), and finally drying in a vacuum drying box at 25°C for 12 h, to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0087] (2) The three-dimensional nickel porphyrin-based catalyst precursor prepared in step (1) was placed in a tube furnace, then nitrogen gas with a flow rate of 50 mL / min was continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature was raised to 300°C in a nitrogen atmosphere for 2 h and kept for 12 h, and then the furnace was cooled to room temperature, to obtain a Cu-Ni-1 carbon-based catalyst (the content of Ni was 6.4% and the content of Cu was 3.1% as tested based on the catalyst), which was recorded as catalyst D.

[0088] Example 5

[0089] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0090] (1) 2.4 g of copper nitrate, 18.6 g of NiTCPP, 1.7 g of 4-bpy and 50 mL of ethanol were mixed and stirred uniformly, then the mixture was placed in a 100 mL reaction kettle with a polytetrafluoroethylene lining, and then static crystallization reaction was carried out at 70°C for 6 h, the reaction liquid was cooled to room temperature within 5 h, then suction filtration was performed, washing with DMF until the filtrate was colorless, washing with ethanol for 5 times (10 mL each time), and finally drying in a vacuum drying box at 25°C for 12 h, to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0091] (2) The three-dimensional nickel porphyrin-based catalyst precursor of step (1) is placed in a tube furnace, then nitrogen gas with a flow rate of 50 mL / min is continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature is raised to 600°C in a nitrogen atmosphere for 6h and kept for 8h, and then the furnace is cooled to room temperature, to obtain a Cu-Ni-2 carbon-based catalyst (the content of Ni is 6.3% and the content of Cu is 3.0% tested based on the catalyst), which is recorded as catalyst E.

[0092] Example 6

[0093] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0094] (1) 2.9 g of zinc nitrate, 18.6 g of NiTCPP, 1.7 g of 4-bpy, 20 mL of DEF and 40 mL of ethanol are mixed and uniformly stirred, then the mixed solution is placed in a 100 mL reaction kettle with a polytetrafluoroethylene lining, and then static crystallization reaction is carried out at 90°C for 24h, the reaction solution is cooled to room temperature within 5h, then filtration is carried out, the filter liquid is washed with DEF until no color is observed, then the filter liquid is washed with ethanol for 3 times (10 mL each time), and finally the filter liquid is placed in a vacuum drying box and dried at 70°C for 12h to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0095] (2) The three-dimensional nickel porphyrin-based catalyst precursor of step (1) is placed in a tube furnace, then nitrogen gas with a flow rate of 60 mL / min is continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature is raised to 700°C in a nitrogen atmosphere for 7h and kept for 8h, and then the furnace is cooled to room temperature, to obtain a Zn-Ni carbon-based catalyst (the content of Ni is 6.4% and the content of Zn is 3.1% tested based on the catalyst), which is recorded as catalyst F.

[0096] Example 7

[0097] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0098] (1) 2.6 g of magnesium nitrate, 18.6 g of NiTCPP, 5.1 g of 4-bpy and 50 mL of DEF are mixed and uniformly stirred, then the mixed solution is placed in a 100 mL reaction kettle with a polytetrafluoroethylene lining, and then static crystallization reaction is carried out at 200°C for 48h, the reaction solution is cooled to room temperature within 12h, then filtration is carried out, the filter liquid is washed with DEF until no color is observed, then the filter liquid is washed with ethanol for 5 times (10 mL each time), and finally the filter liquid is placed in a vacuum drying box and dried at 90°C for 12h to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0099] (2) The three-dimensional nickel porphyrin-based catalyst precursor of step (1) is placed in a tube furnace, then nitrogen gas with a flow rate of 100 mL / min is continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature is raised to 800°C in a nitrogen atmosphere for 8h and kept for 10h, and then the furnace is cooled to room temperature, to obtain a Mg-Ni-1 carbon-based catalyst (the Ni content is 5.4% and the Mg content is 1.0% based on the catalyst), which is recorded as catalyst G.

[0100] Example 8

[0101] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0102] (1) 2.6 g of magnesium nitrate, 18.6 g of NiTCPP, 2.0 g of bpee, 5 mL of DMF and 5 mL of ethanol are mixed and uniformly stirred, then the mixture is placed in a 100 mL reaction kettle with a polytetrafluoroethylene lining, and then static crystallization reaction is carried out at 80°C for 24h, the reaction liquid is cooled to room temperature within 6h, then suction filtration is carried out, DMF is used for washing until the filtrate is colorless, then ethanol is used for washing 5 times (10 mL each time), and finally the mixture is placed in a vacuum drying box and dried at 70°C for 12h to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0103] (2) The three-dimensional nickel porphyrin-based catalyst precursor of step (1) is placed in a tube furnace, then nitrogen gas with a flow rate of 50 mL / min is continuously introduced into the tube furnace to discharge the air in the tube furnace, then the temperature is raised to 800°C in a nitrogen atmosphere for 8h and kept for 10h, and then the furnace is cooled to room temperature, to obtain a Mg-Ni-2 carbon-based catalyst (the Ni content is 6.4% and the Mg content is 1.2% based on the catalyst), which is recorded as catalyst H.

[0104] Example 9

[0105] The embodiment provides a preparation method of a nickel porphyrin carbon-based catalyst, and the preparation method comprises the following steps:

[0106] (1) 1.6 g of calcium nitrate, 18.6 g of NiTCPP, 1.9 g of bpza, 50 mL of DEF and 25 mL of DMF are mixed and uniformly stirred, then the mixture is placed in a 100 mL reaction kettle with a polytetrafluoroethylene lining, and then static crystallization reaction is carried out at 180°C for 48h, the reaction liquid is cooled to room temperature within 12h, then suction filtration is carried out, DEF is used for washing until the filtrate is colorless, then ethanol is used for washing 5 times (10 mL each time), and finally the mixture is placed in a vacuum drying box and dried at 90°C for 12h to obtain a three-dimensional nickel porphyrin-based catalyst precursor;

[0107] (2) The three-dimensional nickel porphyrin-based catalyst precursor prepared in step (1) was placed in a tube furnace, and then nitrogen gas with a flow rate of 50 mL / min was continuously introduced into the tube furnace to discharge the air in the tube furnace, followed by heating to 800°C for 8 h and holding for 10 h under a nitrogen atmosphere, and then the furnace was cooled to room temperature, to obtain a Ca-Ni carbon-based catalyst (the content of Ni was 6.3% and the content of Ca was 1.3% based on the catalyst), which was recorded as catalyst I.

[0108] Example 10

[0109] This example provides a preparation method of a nickel porphyrin carbon-based catalyst, except that 1.1 g of nickel nitrate was added in step (1), and other conditions were the same as in Example 1.

[0110] This example obtained a Ni-Ni-3 carbon-based catalyst (the content of Ni was 9.45% based on the catalyst), which was recorded as catalyst J.

[0111] Example 11

[0112] This example provides a preparation method of a nickel porphyrin carbon-based catalyst, except that 5.1 g of nickel nitrate was added in step (1), and other conditions were the same as in Example 1.

[0113] This example obtained a Ni-Ni-4 carbon-based catalyst (the content of Ni was 10.16% based on the catalyst), which was recorded as catalyst K.

[0114] Example 12

[0115] This example provides a preparation method of a nickel porphyrin carbon-based catalyst, except that 14.6 g of NiTCPP was added in step (1), and other conditions were the same as in Example 1.

[0116] This example obtained a Ni-Ni-5 carbon-based catalyst (the content of Ni was 9.32% based on the catalyst), which was recorded as catalyst L.

[0117] Example 13

[0118] This example provides a preparation method of a nickel porphyrin carbon-based catalyst, except that 48.6 g of NiTCPP was added in step (1), and other conditions were the same as in Example 1.

[0119] This example obtained a Ni-Ni-6 carbon-based catalyst (the content of Ni was 10.36% based on the catalyst), which was recorded as catalyst M.

[0120] Example 14

[0121] This embodiment provides a method for preparing a nickel porphyrin carbon-based catalyst. Except for the addition of 0.32g of pz in step (1), all other conditions are the same as in Example 1.

[0122] The Ni-Ni-7 carbon-based catalyst obtained in this embodiment (based on the catalyst, the Ni content was measured to be 10.13%), denoted as catalyst N.

[0123] Example 15

[0124] This embodiment provides a method for preparing a nickel porphyrin carbon-based catalyst. Except for the addition of 3g of pz in step (1), all other conditions are the same as in Example 1.

[0125] The Ni-Ni-8 carbon-based catalyst obtained in this embodiment (based on the catalyst, the Ni content was measured to be 9.12%) is denoted as catalyst O.

[0126] Comparative Example 1

[0127] This comparative example provides a method for preparing a nickel porphyrin carbon-based catalyst. Except for step (1), where pz was not added and NiTCPP was added to adjust the amount to 57.6g, all other conditions are the same as in Example 1.

[0128] The Ni-Ni-9 carbon-based catalyst obtained in this comparative example (based on the catalyst, the Ni content was measured to be 9.8%), denoted as catalyst P.

[0129] Figure 1 The nitrogen adsorption curves of the nickel porphyrin carbon-based catalysts prepared in Examples 1-2 and Comparative Example 1 are shown below. Figure 1 It can be seen that the specific surface area of ​​the catalysts prepared in Examples 1-2 and Comparative Example 1 is 450 m². 2 / g、570m 2 / g、135m 2 / g. This indicates that the specific surface area of ​​the catalyst was increased by the addition of the second organic ligand.

[0130] Figures 2-4 The pore size distribution curves of the nickel porphyrin carbon-based catalysts prepared in Examples 1-3 and Example 7 are shown below. Figures 2-4 It can be seen that the pore sizes of the catalysts prepared in Examples 1-3 and Example 7 are 0.56 nm, 0.95 nm, 0.98 nm and 0.83 nm, respectively; this shows that the pore size of the nickel porphyrin carbon-based catalyst can be controlled by changing the type of metal salt or the second organic ligand.

[0131] The nickel porphyrin carbon-based catalysts prepared in the above embodiments and comparative examples were all subjected to reduction treatment before use. The reduction treatment methods included:

[0132] The nickel porphyrin carbon-based catalyst 10 g was added into a 100 mL high-pressure reactor, the reactor was replaced with hydrogen for 3 times, and then the hydrogen pressure in the reactor was maintained at 3 MPa. The temperature was increased to 400 ℃ at a rate of 5 ℃ / min and maintained for 6 h. After the reduction of the nickel porphyrin carbon-based catalyst, the temperature was decreased to 25 ℃ within 2 h, and then the catalyst was passivated by introducing 20 mL / min of oxygen-poor air containing 0.5 wt% of O2 for 2 h, to obtain the reduced nickel porphyrin carbon-based catalyst.

[0133] The nickel porphyrin carbon-based catalysts obtained by the reduction of the examples and comparative examples were used for the preparation of succinic anhydride by the hydrogenation of maleic anhydride. The application method comprises:

[0134] The evaluation was carried out in a 100 mL high-pressure reactor, using tetrahydrofuran as the solvent, a maleic anhydride concentration of 30 wt%, a hydrogen pressure of 5 MPa, a reaction temperature of 120 ℃, a reaction time of 2 h, a catalyst / maleic anhydride mass ratio of 0.1, and a cycle number of 0, 10 and 30, respectively. After the reaction, the reaction liquid was analyzed by gas chromatography to determine the contents of maleic anhydride (MA), succinic anhydride (SAA), γ-butyrolactone (GBL) and 1,2,3,4-butanetetracarboxylic acid dianhydride (BDA), and the conversion rate and yield were calculated.

[0135] The performance indicators of the nickel porphyrin carbon-based catalyst were calculated as follows:

[0136] MA conversion rate = number of moles of converted MA / number of moles of input MA × 100%

[0137] SAA yield = number of moles of generated SAA / number of moles of converted MA × 100%

[0138] Catalytic performance of the nickel porphyrin carbon-based catalyst:

[0139] After the hydrogenation reaction of maleic anhydride was completed, the nickel porphyrin carbon-based catalyst obtained by filtration was washed with tetrahydrofuran, dried, and then reduced again, and then the hydrogenation reaction of maleic anhydride was repeated.

[0140] The catalytic results of the nickel porphyrin carbon-based catalysts prepared in the above examples and comparative examples are shown in Table 1.

[0141] Table 1

[0142]

[0143]

[0144]

[0145] From Table 1, the following points can be obtained:

[0146] (1) the nickel porphyrin carbon-based catalyst prepared by the preparation method provided in embodiments 1-9 has excellent catalytic performance in the maleic anhydride hydrogenation reaction process, the raw material conversion rate and product selectivity of the catalyst can be effectively adjusted by adjusting the types of the second organic ligand and the metal salt, the conversion rate of maleic anhydride is above 96.24%, and the highest can reach 100%, the selectivity of succinic anhydride is above 95.27%, and the highest can reach 99.83%; meanwhile, the catalyst shows excellent stability and cycle performance, after 30 cycles, the conversion rate of maleic anhydride is above 95.12%, the selectivity of succinic anhydride is above 93.28%, and the catalyst still has relatively high raw material conversion rate and product selectivity;

[0147] (2) it can be known from the comparison of embodiment 1 and embodiments 10-11 that when the addition amount of the second metal ligand is too small, the difficulty of the substrate approaching the active metal in the porphyrin center is increased, and the conversion rate of maleic anhydride and the selectivity of succinic anhydride are both decreased; when the addition amount of the second metal ligand is too large, the proportion of NiTCPP in the framework is low, and the coordination mode of the framework is changed, so that the conversion rate of maleic anhydride and the selectivity of succinic anhydride are both decreased;

[0148] (3) it can be known from the comparison of embodiment 1 and embodiments 12-13 that when the addition amount of NiTCPP is too small, the coordination mode of the metal node is changed, the proportion of the active metal is reduced, and the conversion rate of maleic anhydride and the selectivity of succinic anhydride are both decreased; when the addition amount of NiTCPP is too large, the specific surface area of the catalyst is reduced, and the conversion rate of maleic anhydride and the selectivity of succinic anhydride are both decreased;

[0149] (4) it can be known from the comparison of embodiment 1 and embodiments 14-15 and comparative example 1 that when no second organic ligand is added or the addition amount of the second organic ligand is reduced, the specific surface area of the catalyst is reduced, and the conversion rate of maleic anhydride and the selectivity of succinic anhydride are both decreased; when the addition amount of the second organic ligand is too large, the proportion of the active metal in the framework is low, and the coordination mode of the framework is changed, so that the conversion rate of maleic anhydride and the selectivity of succinic anhydride are both decreased.

[0150] The applicant declares that the above embodiments are used to illustrate the detailed structural features of the present application, but the present application is not limited to the above detailed structural features, that is, the present application does not mean that the present application must rely on the above detailed structural features to be implemented. It should be understood by those skilled in the art that any improvement of the present application, equivalent replacement of the components selected by the present application and addition of auxiliary components, selection of specific modes, etc. fall within the protection scope and disclosure scope of the present application.

Claims

1. Use of a nickel porphyrin carbon-based catalyst in the hydrogenation reaction of maleic anhydride, characterized in that, The nickel porphyrin carbon-based catalyst is prepared by the following preparation method: (1) mixing a metal salt, a first metal organic ligand, a second organic ligand and an organic solvent, and then performing a crystallization reaction to obtain a three-dimensional nickel porphyrin-based catalyst precursor; The metal salt includes any one or a combination of at least two of zinc nitrate, cobalt nitrate, copper nitrate, nickel nitrate, magnesium nitrate or calcium nitrate; the first metal organic ligand includes nickel tetracarboxyphenyl porphyrin; and the second organic ligand includes any one or a combination of at least two of pyrazine, 2,2'-bipyridine, 4,4'-bipyridine, 2,2'-dimethyl-4,4'-bipyridine, 1,2-bis(4-pyridyl)ethylene, trans-1,2-bis(4-pyridyl)diazene or 3,6-di-4-pyridyl-1,2,4,5-tetrazine; (2) calcining the three-dimensional nickel porphyrin-based catalyst precursor of step (1) to obtain the nickel porphyrin carbon-based catalyst.

2. Use according to claim 1, characterized in that, The molar ratio of the metal salt and the first metal organic ligand in step (1) is (1-1.2):(2-5).

3. Use according to claim 1, characterized in that, The molar ratio of the first metal organic ligand and the second organic ligand in step (1) is (2-5):(1-3).

4. Use according to claim 1, characterized in that, The molar ratio of the metal salt and the organic solvent in step (1) is (1-1.2):(10-85).

5. The use according to claim 1, characterized in that, The metal salt in step (1) is nickel nitrate or copper nitrate.

6. Use according to claim 1, characterized in that, The second organic ligand in step (1) is pyrazine or 4,4'-bipyridine.

7. Use according to claim 1, characterized in that, The organic solvent in step (1) includes any one or a combination of at least two of N,N-diethylformamide, N,N-dimethylformamide, N,N-dimethylacetamide or ethanol.

8. Use according to claim 7, characterized in that, The organic solvent in step (1) is N,N-dimethylformamide.

9. The use according to claim 1, characterized in that, The mixed solution after mixing in step (1) is placed in a reaction kettle.

10. Use according to claim 9, characterized in that, The volume ratio of the mixed solution to the reaction kettle is (0.1-0.75):

1.

11. Use according to claim 10, characterized in that, The volume ratio of the mixed solution to the reaction kettle is (0.3-0.6):

1.

12. The use according to claim 1, characterized in that, The temperature of the crystallization reaction in step (1) is 70-200°C.

13. Use according to claim 12, characterized in that, The temperature of the crystallization reaction in step (1) is 90-140°C.

14. The use according to claim 1, characterized in that, The time of the crystallization reaction in step (1) is 6-72 h.

15. Use according to claim 14, characterized in that, The time of the crystallization reaction in step (1) is 12-36 h.

16. The use according to claim 1, characterized in that, After the crystallization reaction in step (1), the reaction solution is further cooled to room temperature, and then sequentially subjected to suction filtration, washing and drying.

17. Use according to claim 16, characterized in that, The washing includes washing with an organic solvent until the filtrate is colorless, and then washing with ethanol for 3-5 times.

18. The use according to claim 16, characterized in that, The drying includes vacuum drying, and the temperature of the drying is 25-90°C.

19. The use according to claim 1, characterized in that, Before the calcination in step (2), nitrogen gas is introduced into the tube furnace to discharge air.

20. The use according to claim 1, characterized in that, The calcination in step (2) is performed in a tube furnace in a nitrogen atmosphere.

21. The use according to claim 19, characterized in that, The flow rate of the introduced nitrogen gas is 10-100 mL / min.

22. The use according to claim 21, characterized in that, The flow rate of the introduced nitrogen gas is 30-60 mL / min.

23. The use according to claim 1, characterized in that, The temperature rising time of the calcination in step (2) is 2-11 h.

24. The use according to claim 23, characterized in that, The temperature rising time of the calcination in step (2) is 3-5 h.

25. The use according to claim 1, characterized in that, The temperature rising end point of the calcination in step (2) is 300-1100°C.

26. The use according to claim 25, characterized in that, The temperature rising end point of the calcination in step (2) is 500-800°C.

27. The use according to claim 1, characterized in that, The holding time of the roasting in step (2) is 2-12 h.

28. The use according to claim 27, characterized in that, The holding time of the roasting in step (2) is 6-8 h.

29. The use according to claim 1, characterized in that, The roasting in step (2) is followed by furnace cooling to room temperature.

30. The use of claim 1, wherein, The preparation method comprises: (1) mixing metal salts, a first metal organic ligand, a second organic ligand and an organic solvent according to a molar ratio of (1-1.2):(2-5):(1-3):(10-85), then placing the mixture in a reaction kettle, and then performing a crystallization reaction at 70-200℃ for 6-72 h, cooling the reaction liquid to room temperature, and then sequentially performing suction filtration, washing and drying to obtain a three-dimensional nickel porphyrin-based catalyst precursor; The metal salts comprise any one or a combination of at least two of zinc nitrate, cobalt nitrate, copper nitrate, nickel nitrate, magnesium nitrate or calcium nitrate; the first metal organic ligand comprises nickel tetracarboxyphenyl porphyrin; and the second organic ligand comprises any one or a combination of at least two of pyrazine, 2,2'-bipyridine, 4,4'-bipyridine, 2,2'-dimethyl-4,4'-bipyridine, 1,2-di(4-pyridyl)ethylene, trans-1,2-di(4-pyridyl)diazene or 3,6-di-4-pyridyl-1,2,4,5-tetrazine; (2) placing the three-dimensional nickel porphyrin-based catalyst precursor in step (1) in a tube furnace, then introducing nitrogen gas into the tube furnace at a flow rate of 10-100 mL / min to discharge air, then performing roasting in a nitrogen atmosphere by increasing the temperature to 300-1100℃ for 2-11 h and holding for 2-12 h, and then furnace cooling to room temperature to obtain the nickel porphyrin carbon-based catalyst.

31. The use according to claim 1, characterized in that, The nickel porphyrin carbon-based catalyst has a three-dimensional pore structure. The specific surface area of the nickel porphyrin carbon-based catalyst is ≥300 m² / g. The pore size of the nickel porphyrin carbon-based catalyst is adjusted by changing the type of metal salt or second organic ligand.

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