CN116510761A - Method for preparing nitrogen-doped mesoporous carbon nano alloy catalyst by double-ligand MOFs and application - Google Patents

Abstract

The invention belongs to the technical field of catalysts, in particular to a method for preparing a porphyrin-based MOFs nano-mesoporous carbon-supported alloy nanocatalyst with hierarchical pores, and the use of the catalyst in the synthesis of cyclopentanone compounds from furfural as a biomass-based raw material application. In the present invention, porphyrin and trimesic acid are used as double ligands to coordinate with the transition metal ion M1 to prepare the M1-MOFs material, and then another M2 metal ion is coordinated with the center of the porphyrin ring or impregnated and adsorbed. The M1‑M2‑MOFs precursor was prepared. M1‑M2‑MOFs were annealed at high temperature to prepare a nitrogen-doped mesoporous carbon-supported transition metal alloy nanocatalyst (hereinafter referred to as M1‑M2‑NPC). The obtained M1‑M2‑NPC pair can be used to catalyze the conversion of furfural into cyclopentanone.

Description

Method and application of nitrogen-doped mesoporous carbon nanoalloy catalyst prepared by double-ligand MOFs

technical field

The invention belongs to the technical field of catalysts, and specifically relates to a method for preparing a porphyrin-based MOFs nano-mesoporous carbon-supported alloy nanocatalyst with hierarchical pores, and the use of the catalyst in the synthesis of cyclopentanone compounds from furfural as a biomass-based raw material application.

Background technique

Utilizing biomass to produce valuable chemicals is an effective way to reduce dependence on fossil resources and increase the supply of organic fine chemicals. Furfural (FFA), a lignocellulose-derived furan aldehyde, is an important biobased platform compound positioned as a stable and renewable source of organic non-fossil carbon for the production of value-added chemicals and fuels. Furfural is a multifunctional compound (having a furan ring and a carbonyl group). Various fine chemicals can be prepared through various reactions such as catalytic reduction and ring opening, such as the efficient synthesis of cyclopentanone (CPO) through catalytic hydrogenation and isomerization reactions And cyclopentanol (CPL), etc. Among them, cyclopentanone (CPO) is an important fine chemical raw material for the production of medicines, pesticides, dyes and spices.

In the process of converting furfural into cyclopentanone, in order to improve the conversion rate of raw materials and product selectivity, and reduce production costs, researchers research and develop various catalysts. "Biomass-derived furfural conversion over Ni/CNTcatalysts at the interface of water-oil emulsion droplets", HERRERA C et al. used Ni nanoparticles at the liquid-liquid interface and distributed them on the interface of emulsion droplets to form a stable Pickering emulsion, and then The catalyst (Ni/CNTox for short) was prepared by loading carbon nanotubes. Ni/CNTox is an effective catalyst for converting furfural to cyclopentanone. Under the optimized conditions (using water as solvent, 200°C, 2MPa H ₂ , 1h), the conversion rate of furfural is 35%, and the yield of cyclopentanone is 25%. . The catalyst has low selectivity for converting furfural into cyclopentanone, and after three cycles, the yield of CPO drops significantly, making it difficult to catalyze continuously and effectively, and is not suitable for industrial production and application.

"Pd/Cu-MOF as a highly efficient catalyst for synthesis of cyclopentanone compounds from biomass-derived furanic aldehydes", DENG Q et al. used Cu-MOFs with different chemical structures (such as Cu ₃ (BTC) ₂ ) supports to prepare Pd/Cu-MOFs precursor, and then annealed to obtain a Pd/Cu-C bifunctional catalyst. Since Cu-BTC (metal ions bridged by trimer acid) has strong acidity, it can effectively fix Cu and Pd metal ions, making them dispersed uniformly and orderly. In the catalytic conversion of furfural to cyclopentanone, the activity of the catalyst decreased after the catalyst was circulated for 5 times. TEM analysis showed that, compared with the high dispersion of Pd nanoparticles on the unreacted catalyst, the aggregation of Pd nanoparticles on the catalyst was serious after 5 cycles. The N ₂ adsorption-desorption process after the catalyst was cycled 5 times also showed that the specific surface area of the catalyst decreased significantly, which was the reason for the decrease of the catalyst activity.

Therefore, it will be of great significance to prepare a catalyst for promoting the conversion of furfural to cyclopentanone with good selectivity and high stability, and realize its industrial application.

Contents of the invention

One of the purposes of the present invention is to provide a method for preparing nitrogen-doped mesoporous carbon nano-alloy catalyst by double-ligand MOFs. ₃ ) PP), Trimellitic acid (BTC) as a double-ligand MOFs material (referred to as M-TCOPP-BTC-MOF), as a precursor to prepare a nitrogen-doped mesoporous carbon-supported transition metal alloy nanocatalyst, the The catalyst can be used to catalyze the conversion of furfural into cyclopentanone, has the characteristics of good selectivity and high stability, and can realize industrial application.

In order to achieve the above object, the present invention adopts the following technical scheme: a method for preparing a nitrogen-doped mesoporous carbon nano-alloy catalyst by double-ligand MOFs, comprising the following steps:

S1. Dissolve the soluble metal salt M1 in an organic solvent, and then add tetrakis(4-methoxycarbonylphenyl)porphyrin with a molar ratio of 1:(0.1-10), namely T(4-COOCH ₃ )PP and Trimellitic acid is BTC, to obtain a mixed solution, stir until the material is completely dissolved, adjust the pH value of the solution to 2-4, transfer the mixed solution into a polytetrafluoroethylene reactor, and continue at a temperature of 50-140°C After reacting for 2-48 hours, the precipitate was separated after cooling to room temperature, and after drying, the MOFs material with T(4-COOCH ₃ )PP and BTC as double ligands was prepared, referred to as M ₁ -TCOPP-BTC-MOFs;

S2. Dissolving the soluble metal salt M2 in the ethanol solution, adding the M ₁ -TCOPP-BTC-MOFs prepared in step S1, the metal in the M ₁ -TCOPP-BTC-MOFs and the metal in the soluble metal salt M2 The molar ratio of the metal is 10:1-1:10, stirring and mixing uniformly at room temperature, and vacuum drying to obtain the solid catalyst precursor M1-M2-TCOPP-BTC-MOFs;

S3. Take M1-M2-TCOPP-BTC-MOFs and pulverize them evenly, place them in a tube furnace, anneal at 200-800°C for 2-8 hours in an atmosphere of air, hydrogen or inert gas, cool to room temperature and grind , to obtain a nitrogen-doped mesoporous carbon nanoalloy catalyst, that is, M1-M2-NPC.

Further improvements in the preparation of nitrogen-doped mesoporous carbon nanoalloy catalysts as dual-ligand MOFs:

Preferably, the molar ratio of porphyrin (T(4-COOCH ₃ )PP) to trimesic acid (BTC) in step S1 is 1:(1-3).

Preferably, the soluble metal salt M1 is a single metal salt formed from one of Cu, Co, Ni, Zn, Al, Mn, and Pd.

Preferably, the soluble metal salt M2 is a single metal salt formed by one of Cu, Co, Ni, Zn, Al, Mn, Pd or a composite metal salt formed by two or more, or a single metal salt and a composite metal salt. Any combination of two or more metal salts.

Preferably, the organic solvent is one or two or more of N,N-dimethylformamide (DMF), N,N-diethylformamide (DEF), acetonitrile, dimethyl sulfoxide, and triethanolamine The combination.

Preferably, the organic solvent is a mixed solution of DMF and DEF, and the volume ratio of DMF and DEF is 1:1-1:10, preferably 1:7.

Preferably, the inert gas described in step S3 is one or a combination of two or more of nitrogen, argon, carbon dioxide, and helium.

Preferably, in step S1, the pH value of the solution is adjusted with hydrochloric acid solution, nitric acid solution or sulfuric acid solution; the concentration of the sulfuric acid solution is 1-10 mol/L, preferably 3.3 mol/L.

Preferably, in step S1, the reaction temperature of the mixed solution in the polytetrafluoroethylene reactor is 120-140°C, and the reaction time is 20-24h.

Preferably, the annealing temperature in step S3 is 400-500° C., and the annealing time is 2.5-4 hours.

The second object of the present invention is to provide a use of the nitrogen-doped mesoporous carbon nano-alloy catalyst prepared by any one of the above-mentioned preparation methods in catalyzing the hydrogenation of furfural in aqueous phase to prepare cyclopentanone.

As a further improvement in the use of nitrogen-doped mesoporous carbon nano-alloy catalysts:

Preferably, the catalyst M1-M2-NPC and furfural solution are mixed and added to the autoclave, the air in the autoclave is replaced with _N2 and _H2 in turn, the autoclave is sealed, and then _H2 is introduced until the pressure reaches 1- 20Mpa, start stirring, heat the reactor to 80-200°C for 0.5-8h.

Preferably, the ratio of the mass of the added catalyst to the mass of furfural in the furfural solution is (10-30):100, preferably the ratio is (15-20):100.

Preferably, hydrogen gas is introduced until the pressure reaches 1.5-3Mpa.

Preferably, the reactor is heated to 140-180° C. for 4-6 hours.

Preferably, the solvent of the furfural solution is one or both of water and methanol, and the mass concentration of the furfural solution is 1%-30%.

Preferably, after the reaction finishes, the reaction mixture is analyzed by the gas chromatograph internal standard method wherein the contents of furfural, furfuryl alcohol and cyclopentanone, etc., calculate the conversion rate of furfural and the yield of cyclopentanone, and the M1-M2-NPC catalyst of recovery can be directly or Recycled application after washing treatment.

The beneficial effect of the present invention compared with prior art is:

1) The present invention provides a method for preparing nitrogen-doped mesoporous carbon nano-alloy catalysts from double-ligand MOFs. Tetrakis (4-methoxycarbonylphenyl) porphyrin and trimesic acid are designed as double ligands to prepare double Metal MOFs are used as precursors, and then annealed to prepare M1-M2-NPC carbon-based catalysts. This catalyst can be used to catalyze the conversion of furfural to cyclopentanone, and develop a new technology for the green production of cyclopentanone.

The preparation method uses trimesic acid and tetrakis(4-methoxycarbonylphenyl)porphyrin as double ligands to prepare bimetallic MOFs as precursors, which can provide abundant metal active sites for coordination with metal ions, and prepare The obtained solid catalyst precursor has a hierarchical porous structure, and the M1-M2-NPC obtained by annealing has a high specific surface area and a good pore structure, which is beneficial to the mass transfer process in the catalytic reaction and improves the catalyst activity. Trimellitic acid and tetrakis(4-methoxycarbonylphenyl)porphyrin double ligands form M1-M2-TCOPP-BTC-MOFs, the metal atoms are more uniformly distributed through coordination, and under pyrolysis conditions, the highly dispersed The M1 and M2 metals were transformed into metal nanoparticles in situ, and the M1-M2-NPC catalyst thus obtained had more active sites and was uniformly dispersed, and had better stability.

By changing the ratio of tetrakis(4-methoxycarbonylphenyl)porphyrin and trimesic acid, the N content in M1-M2-NPC can be adjusted conveniently, and the acidity, alkalinity, site and balance of the catalyst support can be controlled. In the process of catalyzing the conversion of furfural into cyclopentanone, it can effectively prevent the self-polymerization of furfural and the polycondensation of intermediate furfuryl alcohol at high temperature in the aqueous phase system, and improve the conversion rate and selectivity of the catalytic reaction.

2) The M1-M2@NPC catalyst prepared by the present invention is applied to catalyze the conversion of furfural into cyclopentanone. The reaction process is as follows. The catalyst can be recycled many times without significant reduction in catalytic efficiency, and the cycle performance is good, which meets the needs of industrial production. The catalyst is safe, non-toxic, green and efficient, environmentally friendly and harmless to the human body, meets the requirements of industrial green production, and has good application prospects.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail below in conjunction with the examples. All other embodiments of all belong to the protection scope of the present invention.

In an embodiment, the definition of furfural conversion rate and cyclopentanone selectivity is:

Furfural conversion rate = (initial furfural amount - reaction residual furfural amount) / initial furfural amount × 100%,

Cyclopentanone selectivity = amount of furfural converted into cyclopentanone/furfural consumed by reaction×100%.

Example 1

This embodiment provides a method for preparing Cu-Co-NPC catalyst 1, and is applied to catalyze furfural to prepare cyclopentanone, as follows:

S1. Preparation of Cu-Co-NPC catalyst 1:

Weigh 1.0473g Cu(NO ₃ ) ₂ ·6H ₂ O and dissolve in 80mL organic solvent, the organic solvent is a mixed solvent with a volume ratio of DMF and DEF of 1:7, and then add 0.5012g of tetrakis (4-methoxy Cylcarbonylphenyl) porphyrin (i.e. T (4-COOCH ₃ ) PP) and 0.1243 g of trimesic acid (i.e. BTC), wherein the molar ratio of T (4-COOCH ₃ ) PP and BTC is 1:1, stirring After Cu(NO ₃ ) ₂ ·6H ₂ O and other materials are completely dissolved, adjust the solution to pH=3 with 3.3 mol/L sulfuric acid solution. Then the mixed solution was transferred to a polytetrafluoroethylene liner, sealed in a stainless steel autoclave, and continued to react at 120°C for 24h. After cooling to room temperature, the reaction mixed solution was separated to obtain a precipitate, and the obtained precipitate was dried overnight at 60°C to obtain Porphyrin (T(4-COOCH ₃ )PP) and trimesic acid (BTC) as double-ligand MOFs material 0.6543g, referred to as Cu-TCOPP-BTC-MOFs;

Weigh 0.1054g of Co(NO ₃ ) ₂ ·6H ₂ O and dissolve it in 20mL ethanol solution, add 0.1054g of the above Cu-TCOPP-BTC-MOFs, the metal Cu and Co in the added Cu-TCOPP-BTC-MOFs( The molar ratio of metal Co in NO ₃ ) ₂ ·6H ₂ O was 1:4, stirred at room temperature for 16 hours, and the mixed solution was vacuum-dried at 80°C to obtain solid catalyst precursor Cu-Co-TCOPP-BTC-MOFs;

The solid catalyst precursor Cu-Co-TCOPP-BTC-MOFs was pulverized evenly, placed in a quartz crucible and then placed in a tube furnace, annealed at a temperature of 500°C in an atmosphere with a flow ratio of nitrogen to hydrogen of 2:1 After 3 hours, after cooling to room temperature, 0.1028 g of nitrogen-doped mesoporous carbon nanoalloy catalyst, ie Cu-Co-NPC catalyst 1, was collected by grinding.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare 20 mg of Cu-Co-NPC catalyst 1 according to the above method, and add 0.1 g of furfural to 5 mL of deionized water (the mass concentration of furfural solution is 2%), and then add them to the autoclave respectively. The mass ratio of furfural in the medium is 20%. Replace the air in the autoclave with _N2 and _H2 in turn, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C Reaction 4h.

After the reaction, cool the reaction mixture to room temperature, add 10 mL of absolute ethanol, mix well, separate and recover the catalyst by centrifugal filtration, and the catalyst can be recycled directly.

The obtained filtrate uses cyclohexanone as an internal standard, and is detected by the internal standard method of gas chromatography, and the conversion rate of furfural is calculated to be 99.9%, and the selectivity of cyclopentanone is 72%.

Example 2:

This embodiment provides a method for preparing Cu-Co-NPC catalyst 2, and is applied to catalyzing furfural to prepare cyclopentanone, as follows:

S1. Preparation of Cu-Co-NPC catalyst 2:

Weigh 1.0324g Cu(NO ₃ ) ₂ ·6H ₂ O and dissolve in 80mL organic solvent, the organic solvent is a mixed solvent with a volume ratio of DMF and DEF of 1:7, and then add 0.5012g of tetrakis (4-methoxy Cylcarbonylphenyl) porphyrin (i.e. T (4-COOCH ₃ ) PP) and 0.2486g trimesic acid (i.e. BTC), wherein the molar ratio of T (4-COOCH ₃ ) PP and BTC is 1:2, stirring Make Cu(NO ₃ ) ₂ ·6H ₂ O and other materials completely dissolved, and adjust the solution to pH=3 with 3.3 mol/L sulfuric acid solution. Then the mixed solution was transferred to a polytetrafluoroethylene liner, sealed in a stainless steel autoclave, and continued to react at 120°C for 24h. After cooling to room temperature, the reaction mixed solution was separated to obtain a precipitate, and the obtained precipitate was dried overnight at 60°C to obtain Porphyrin (T(4-COOCH ₃ )PP) and trimesic acid (BTC) are double-ligand MOFs material 0.5756g, referred to as Cu-TCOPP-BTC-MOFs.

Weigh 0.2012g of Co(NO ₃ ) ₂ ·6H ₂ O and dissolve it in 20mL ethanol solution, add 0.1076g of the above Cu-TCOPP-BTC-MOFs, the metal Cu and Co in the added Cu-TCOPP-BTC-MOFs( The molar ratio of metal Co in NO ₃ ) ₂ ·6H ₂ O was 1:4, stirred at room temperature for 16 h, and the mixed solution was vacuum-dried at 80°C to obtain solid catalyst precursor Cu-Co-TCOPP-BTC-MOFs.

The solid catalyst precursor Cu-Co-TCOPP-BTC-MOFs was pulverized evenly, placed in a quartz crucible and then placed in a tube furnace, annealed at a temperature of 500°C in an atmosphere with a flow ratio of nitrogen to hydrogen of 2:1 After 3 hours, after cooling to room temperature, 0.1423 g of nitrogen-doped mesoporous carbon nanoalloy catalyst, ie Cu-Co-NPC catalyst 2, was collected by grinding.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare 20 mg of Cu-Co-NPC catalyst 2 with reference to the above method, and add 0.1 g of furfural to 5 mL of deionized water (the mass concentration of furfural solution is 2%), and then add them to the autoclave respectively. The mass ratio of furfural in the medium is 20%. Replace the air in the autoclave with _N2 and _H2 in turn, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C Reaction 4h.

After the reaction, cool the reaction mixture to room temperature, add 10 mL of absolute ethanol, mix well, separate and recover the catalyst by centrifugal filtration, and the catalyst can be recycled directly.

Compared with Example 1, due to the increase of the second ligand, the metal content in M1 increases after the reaction, and the addition of M2 is adjusted so that the ratio of the two metals is the same as in Example 1. In this embodiment, the nitrogen content in the catalyst is reduced by adjusting the molar ratio of the two ligands in the catalyst to reach a more suitable range of nitrogen content, thereby improving the selectivity of cyclopentanone. The obtained filtrate uses cyclohexanone as an internal standard, and is detected by the gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 99.9%, and the selectivity of cyclopentanone is 86%.

Example 3:

This embodiment provides a method in which Cu-Co-NPC catalyst 2 is applied to catalyze furfural to prepare cyclopentanone, specifically as follows:

S1. Preparation of Cu-Co-NPC catalyst 2: refer to the specific steps in Example 2.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare 10 mg of Cu-Co-NPC catalyst 2 with reference to the above method, and add 0.1 g of furfural to 5 mL of deionized water (the mass concentration of furfural solution is 2%), and then add them to the autoclave respectively. The mass ratio of furfural in the medium is 10%. Replace the air in the autoclave with _N2 and _H2 in sequence, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C Reaction 4h.

Compared with Example 2, this embodiment adjusted the ratio of the mass of the added catalyst to the mass of furfural in the furfural solution. The obtained filtrate uses cyclohexanone as an internal standard, and is detected by the gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 70%, and the selectivity of cyclopentanone is 68%.

Example 4:

This embodiment provides a method in which Cu-Co-NPC catalyst 2 is applied to catalyze furfural to prepare cyclopentanone, specifically as follows:

S1. Preparation of Cu-Co-NPC catalyst 2: refer to the specific steps in Example 2.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare 30 mg of Cu-Co-NPC catalyst 2 with reference to the above method, and add 0.1 g of furfural to 5 mL of deionized water (the mass concentration of furfural solution is 2%), and then add them to the autoclave respectively. The mass ratio of furfural in the medium is 30%. Replace the air in the autoclave with _N2 and _H2 in turn, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C Reaction 4h.

Compared with Example 2, this embodiment adjusted the ratio of the mass of the added catalyst to the mass of furfural in the furfural solution. The obtained filtrate uses cyclohexanone as an internal standard, and is detected by gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 99.9%, and the selectivity of cyclopentanone is 84%.

Example 5:

This embodiment provides a kind of method for preparing Cu-Ni-NPC catalyst, and is applied to catalyzing furfural to prepare cyclopentanone, specifically as follows:

S1, prepare Cu-Ni-NPC catalyst:

Weigh 1.0324g Cu(NO ₃ ) ₂ ·6H ₂ O and dissolve in 80mL organic solvent, the organic solvent is a mixed solvent with a volume ratio of DMF and DEF of 1:7, and then add 0.5012g of tetrakis (4-methoxy Cylcarbonylphenyl) porphyrin (i.e. T (4-COOCH ₃ ) PP) and 0.2486g trimesic acid (i.e. BTC), wherein the molar ratio of T (4-COOCH ₃ ) PP and BTC is 1:2, stirring Make Cu(NO ₃ ) ₂ ·6H ₂ O and other materials completely dissolved, and adjust the solution to pH=3 with 3.3 mol/L sulfuric acid solution. Then the mixed solution was transferred to a polytetrafluoroethylene liner, sealed in a stainless steel autoclave, and continued to react at 120°C for 24h. After cooling to room temperature, the reaction mixed solution was separated to obtain a precipitate, and the obtained precipitate was dried overnight at 60°C to obtain Porphyrin (T(4-COOCH ₃ )PP) and trimesic acid (BTC) are double-ligand MOFs material 0.5756g, referred to as Cu-TCOPP-BTC-MOFs.

Weigh 0.1011g of Ni(NO ₃ ) ₂ ·6H ₂ O and dissolve it in 20mL ethanol solution, add 0.1076g of the above Cu-TCOPP-BTC-MOFs, the metal Cu and Ni in the added Cu-TCOPP-BTC-MOFs ( The molar ratio of metal Ni in NO ₃ ) ₂ ·6H ₂ O was 1:2, stirred at room temperature for 16 h, and the mixed solution was vacuum-dried at 80°C to obtain solid catalyst precursor Cu-Ni-TCOPP-BTC-MOFs.

The solid catalyst precursor Cu-Ni-TCOPP-BTC-MOFs was pulverized evenly, placed in a quartz crucible and then placed in a tube furnace, annealed at a temperature of 500°C in an atmosphere with a flow ratio of nitrogen to hydrogen of 2:1 After 3 hours, after cooling to room temperature, 0.1002 g of nitrogen-doped mesoporous carbon nanoalloy catalyst, ie Cu-Ni-NPC catalyst, was obtained by grinding and collecting.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare a total of 20 mg of Cu-Ni-NPC catalyst with reference to the above method, and another 0.1 g of furfural is added to 5 mL of deionized water (the mass concentration of the furfural solution is 2%), and then respectively added to the autoclave. The mass ratio of furfural was 20%, and the air in the autoclave was replaced with _N2 in turn, the autoclave was sealed, and _H2 was introduced until the pressure reached 3.0MPa, the autoclave was started to stir, and the autoclave was heated to 180°C for 4h.

After the reaction, cool the reaction mixture to room temperature, add 10 mL of absolute ethanol, mix well, separate and recover the catalyst by centrifugal filtration, and the catalyst can be recycled directly.

The obtained filtrate uses cyclohexanone as an internal standard, and is detected by gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 99.9%, and the selectivity of cyclopentanone is 80%.

Embodiment 6:

This embodiment provides a method for preparing Co-Ni-NPC catalyst, and is applied to catalyze furfural to prepare cyclopentanone, as follows:

Preparation of S1, Co-Ni-NPC catalyst:

Weigh 1.0241g Co(NO ₃ ) ₂ ·6H ₂ O and dissolve it in 80mL of organic solvent, the organic solvent is a mixed solvent with a volume ratio of DMF and DEF of 1:7, and then add 0.5012g of tetrakis(4-methoxy Cylcarbonylphenyl) porphyrin (i.e. T (4-COOCH ₃ ) PP) and 0.2486g trimesic acid (i.e. BTC), wherein the molar ratio of T (4-COOCH ₃ ) PP and BTC is 1:2, stirring Co(NO ₃ ) ₂ ·6H ₂ O and other materials are completely dissolved, and the solution is adjusted to pH=3 with 3.3 mol/L sulfuric acid solution. Then the mixed solution was transferred to a polytetrafluoroethylene liner, sealed in a stainless steel autoclave, and continued to react at 120°C for 24h, and after cooling to room temperature, the reaction mixed solution was separated to obtain a precipitate, and the obtained precipitate was dried overnight at 60°C to obtain Porphyrin (T(4-COOCH ₃ )PP) and trimesic acid (BTC) are double-ligand MOFs material 0.4687g, referred to as Co-TCOPP-BTC-MOFs.

Weigh 0.1123g of Ni(NO ₃ ) ₂ ·6H ₂ O and dissolve it in 20mL ethanol solution, add 0.1025g of the above-mentioned Co-TCOPP-BTC-MOFs, the metal Cu and Co in the added Cu-TCOPP-BTC-MOFs( The molar ratio of metal Co in NO ₃ ) ₂ ·6H ₂ O was 1:2, stirred at room temperature for 16 h, and the mixed solution was vacuum-dried at 80°C to obtain solid catalyst precursor Co-Ni-TCOPP-BTC-MOFs.

The solid catalyst precursor Co-Ni-TCOPP-BTC-MOFs was pulverized evenly, placed in a quartz crucible and placed in a tube furnace, annealed at a temperature of 500°C in an atmosphere with a flow ratio of nitrogen to hydrogen of 2:1 After 3 hours, after cooling to room temperature, 0.1002 g of nitrogen-doped mesoporous carbon nanoalloy catalyst, namely Co-Ni-NPC catalyst 2, was collected by grinding.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare a total of 20 mg of Co-Ni-NPC catalyst with reference to the above method, and add 0.1 g of furfural to 5 mL of deionized water (the mass concentration of the furfural solution is 2%), and then add it to the autoclave respectively. The mass ratio of furfural is 20%. Replace the air in the autoclave with _N2 and _H2 in turn, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C for reaction 4h.

After the reaction, cool the reaction mixture to room temperature, add 10 mL of absolute ethanol, mix well, separate and recover the catalyst by centrifugal filtration, and the catalyst can be recycled directly.

The obtained filtrate uses cyclohexanone as an internal standard, and is detected by the gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 99.9%, and the selectivity of cyclopentanone is 83%.

Embodiment 7:

This embodiment provides a method in which Cu-Co-NPC catalyst 2 is applied to catalyze furfural to prepare cyclopentanone, specifically as follows:

S1. Preparation of Cu-Co-NPC catalyst 2: refer to the specific steps in Example 2.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare 50 mg of Cu-Co-NPC catalyst 2 with reference to the above method, get another 0.25 g of furfural and add it to 5 mL of deionized water (the mass concentration of furfural solution is 5%), then add it to the autoclave respectively, and add the mass of catalyst to account for the amount of furfural solution The mass ratio of furfural in the medium is 20%. Replace the air in the autoclave with _N2 and _H2 in turn, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C Reaction 4h.

After the reaction, cool the reaction mixture to room temperature, add 10 mL of absolute ethanol, mix well, separate and recover the catalyst by centrifugal filtration, and the catalyst can be recycled directly.

Compared with Example 2, this example increases the concentration of the reactant furfural in the preparation of cyclopentanone from furfural, and the side reaction of polycondensation is obvious during the reaction process, resulting in a decrease in the conversion rate of furfural and the selectivity of cyclopentanone. The obtained filtrate uses cyclohexanone as an internal standard, and is detected by gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 90%, and the selectivity of cyclopentanone is 40%.

Embodiment 8:

This embodiment provides a method in which Cu-Co-NPC catalyst 2 is applied to catalyze furfural to prepare cyclopentanone, specifically as follows:

S1. Preparation of Cu-Co-NPC catalyst 2: refer to the specific steps in Example 2.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare 50 mg of Cu-Co-NPC catalyst 2 with reference to the above method, and add 0.50 g of furfural to 5 mL of deionized water (the mass concentration of furfural solution is 10%), and then add them to the high-pressure reactor respectively. The mass ratio of furfural in the medium is 20%. Replace the air in the autoclave with _N2 and _H2 in turn, seal the autoclave, and then feed _H2 until the pressure reaches 3.0MPa, start the autoclave to stir, and heat the autoclave to 180°C Reaction 4h.

Compared with Examples 2 and 5, after the concentration of the reactant furfural was continuously increased in this example, the side reaction of polycondensation was obvious during the reaction process, resulting in a decrease in the conversion rate of furfural and the selectivity of cyclopentanone. The obtained filtrate uses cyclohexanone as the internal standard substance, and is detected by the internal standard method of gas chromatography, and the conversion rate of furfural is calculated to be 65%, and the selectivity of cyclopentanone is 16%.

Embodiment 9:

This embodiment provides a method for preparing Cu-Co-Ni-NPC catalyst, and is applied to catalyzing furfural to prepare cyclopentanone, specifically as follows:

S1, prepare Cu-Co-Ni-NPC catalyst:

Weigh 1.0324g Cu(NO ₃ ) ₂ ·6H ₂ O and dissolve in 80mL organic solvent, the organic solvent is a mixed solvent with a volume ratio of DMF and DEF of 1:7, and then add 0.5012g of tetrakis (4-methoxy Cylcarbonylphenyl) porphyrin (i.e. T (4-COOCH ₃ ) PP) and 0.2486g trimesic acid (i.e. BTC), wherein the molar ratio of T (4-COOCH ₃ ) PP and BTC is 1:2, stirring Make Cu(NO ₃ ) ₂ ·6H ₂ O and other materials completely dissolved, and adjust the solution to pH=3 with 3.3 mol/L sulfuric acid solution. Then the mixed solution was transferred to a polytetrafluoroethylene liner, sealed in a stainless steel autoclave, and continued to react at 120°C for 24h. After cooling to room temperature, the reaction mixed solution was separated to obtain a precipitate, and the obtained precipitate was dried overnight at 60°C to obtain Porphyrin (T(4-COOCH ₃ )PP) and trimesic acid (BTC) are double-ligand MOFs material 0.5756g, referred to as Cu-TCOPP-BTC-MOFs.

Weigh 0.2012g of Co(NO ₃ ) ₂ ·6H ₂ O and 0.2012g of Ni(NO ₃ ) ₂ ·6H ₂ O and dissolve them in 20mL of ethanol solution, add 0.1076g of the above Cu-TCOPP-BTC-MOFs, at room temperature After stirring for 16 h, the mixed solution was vacuum-dried at 80 °C to obtain solid catalyst precursor Cu-Co-Ni-TCOPP-BTC-MOFs.

The solid catalyst precursor Cu-Co-Ni-TCOPP-BTC-MOFs was pulverized evenly, placed in a quartz crucible and then placed in a tube furnace. After temperature annealing for 3 h, after cooling to room temperature, 0.1924 g of nitrogen-doped mesoporous carbon nanoalloy catalyst, ie, Cu-Co-Ni-NPC catalyst, was collected by grinding.

S2, Catalyzing furfural to prepare cyclopentanone:

Prepare Cu-Co-Ni-NPC catalyst with reference to above-mentioned method 20mg altogether, add (the mass concentration of furfural solution is 2%) in 5mL deionized water, then add in the autoclave respectively, the quality of adding catalyzer accounts for the furfural quality in the furfural solution The ratio is 20%. Replace the air in the autoclave with N ₂ and H ₂ in turn, seal the autoclave, and then feed H ₂ until the pressure reaches 3.0 MPa, start the autoclave to stir, and heat the autoclave to 180°C for 4 hours.

After the reaction, cool the reaction mixture to room temperature, add 10 mL of absolute ethanol, mix well, separate and recover the catalyst by centrifugal filtration, and the catalyst can be recycled directly.

Compared with Example 2, the soluble metal salt M2 in this example uses a combination of two single metal salts to prepare a three-component nano-alloy catalyst. The obtained filtrate uses cyclohexanone as an internal standard, and is detected by gas chromatography internal standard method, and the conversion rate of furfural is calculated to be 99.9%, and the selectivity of cyclopentanone is 80%.

Those skilled in the art should understand that the above descriptions are only some specific implementation manners of the present invention, rather than all examples. It should be pointed out that many variations and improvements can be made by those skilled in the art, and all variations or improvements that do not exceed the scope of the claims should be regarded as the protection scope of the present invention.

Claims (10)

1. The method for preparing the nitrogen-doped mesoporous carbon nano alloy catalyst by using the double-ligand MOFs is characterized by comprising the following steps of:

s1, dissolving soluble metal salt M1 in an organic solvent, and adding tetra (4-methoxy carbonyl phenyl) porphyrin (T (4-COOCH) with the mol ratio of 1 (0.1-10) ₃ ) PP and trimesic acid (BTC) are mixed to obtain mixed solution, and the mixed solution is stirred until the materials are completely dissolved, and the dissolution is regulatedThe pH value of the solution is 2-4, the mixed solution is transferred into a polytetrafluoroethylene reaction kettle to continuously react for 2-48 hours at the temperature of 50-140 ℃, the solution is cooled to room temperature and separated to obtain a precipitate, and the precipitate is dried to obtain the T (4-COOCH) ₃ ) MOFs material with PP and BTC as double ligands, abbreviated as M ₁ -TCOPP-BTC-MOFs；

S2, dissolving soluble metal salt M2 in ethanol solution, and adding M prepared in the step S1 ₁ -TCOPP-BTC-MOFs, said M ₁ The molar ratio of the metal in the TCOPP-BTC-MOFs to the metal in the soluble metal salt M2 is 10:1-1:10, the mixture is stirred and mixed uniformly at normal temperature, and the solid catalyst precursor M1-M2-TCOPP-BTC-MOFs is obtained by vacuum drying;

s3, taking M1-M2-TCOPP-BTC-MOFs, crushing uniformly, placing in a tube furnace, annealing for 2-8 hours at 200-800 ℃ in the atmosphere of air, hydrogen or inert gas, cooling to room temperature, and grinding to obtain the nitrogen-doped mesoporous carbon nano alloy catalyst, namely M1-M2-NPC.

2. The method of preparing nitrogen-doped mesoporous carbon nano alloy catalysts according to claim 1, wherein said soluble metal salt M1 is a single metal salt of Cu, co, ni, zn, al, mn, pd.

3. The method for preparing the nitrogen-doped mesoporous carbon nano alloy catalyst according to claim 1, wherein the soluble metal salt M2 is a single metal salt formed by one of Cu, co, ni, zn, al, mn, pd or a composite metal salt formed by two or more of Cu, co, ni, zn, al, mn, pd, or a combination of any two or more of the single metal salt and the composite metal salt.

4. The method for preparing the nitrogen-doped mesoporous carbon nano alloy catalyst according to claim 1, wherein the organic solvent is one or more of N, N-Dimethylformamide (DMF), N-Diethylformamide (DEF), acetonitrile, dimethyl sulfoxide and triethanolamine.

5. The method for preparing nitrogen-doped mesoporous carbon nano alloy catalysts according to claim 1, wherein the inert gas in step S3 is one or a combination of more than two of nitrogen, argon, carbon dioxide and helium.

6. Use of the nitrogen-doped mesoporous carbon nano alloy catalyst prepared by the preparation method of any one of claims 1-5 in catalyzing water phase hydrogenation of furfural to prepare cyclopentanone.

7. The method for preparing the nitrogen-doped mesoporous carbon nano alloy catalyst according to claim 6, wherein the catalyst M1-M2-NPC and the furfural solution are mixed and then added into a high-pressure reaction kettle, and N is used sequentially ₂ And H ₂ Air in the high-pressure reaction kettle is replaced, the reaction kettle is sealed, and then H is introduced ₂ And (3) starting stirring until the pressure reaches 1-20Mpa, and heating the reaction kettle to 80-200 ℃ for reaction for 0.5-8h.

8. The use of the nitrogen-doped mesoporous carbon nano alloy catalyst according to claim 7, wherein the ratio of the mass of the catalyst added to the mass of furfural in the furfural solution is (10-30): 100.

9. The use of the nitrogen-doped mesoporous carbon nano alloy catalyst according to claim 7, wherein the solvent of the furfural solution is one or two of water and methanol, and the mass concentration of the furfural solution is 1% -30%.

10. The use of the nitrogen-doped mesoporous carbon nano alloy catalyst according to claim 7, wherein after the reaction is finished, the content of furfural, furfuryl alcohol, cyclopentanone and the like in the reaction mixture is analyzed by a gas chromatograph internal standard method, the conversion rate of furfural and the yield of cyclopentanone are calculated, and the recovered M1-M2-NPC catalyst can be directly recycled or recycled after washing treatment.