Preparation method and application of Co-MOF-supported copper catalyst

Abstract

The present invention relates to a preparation method and application of a copper-loaded Co-MOF catalyst; a metal-organic framework material with a structural unit chemical formula of {[Co2(L)(μ3-F)(H2O)3]·H2O}; in the Co-MOF structure, L is the organic ligand 1,3-bis(3,5-dicarboxyphenyl)imidazole, and the framework is formed by connecting four metal ions Co(II) and two coordination anions μ3-F to form a [Co4] cluster. With this cluster as the core, it coordinates with the carboxyl oxygen and water of eight ligands respectively. Each divalent cobalt has a six-coordinate coordination mode, ultimately constituting a three-dimensional long-range ordered framework structure. The Cu@Co-MOF catalyst has two catalytic active centers, namely copper nanoparticles and Co(II). During the catalytic oxidation of tetrahydroisoquinoline, the yield of 3,4-dihydroisoquinoline generated is as high as 95%. This catalyst also avoids the use of precious metals and saves costs.

Description

Technical Field

[0001] The present invention belongs to the field of derivative catalysis of MOF materials, and specifically relates to a preparation method of a three-dimensional Co-MOF constructed based on 1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride and loaded with copper catalyst material, and its application in catalyzing the efficient and selective oxidation of tetrahydroisoquinoline to generate 3,4-dihydroisoquinoline. Background Art

[0002] 3,4-Dihydroisoquinoline compounds are very important alkaloids and are used as building blocks of pharmaceutical molecules to treat various diseases. For example, Corylucinine, Famotine, and Nelumstemine are used to treat Alzheimer's disease, influenza, and HIV, respectively. There are many methods for the synthesis of 3,4-dihydroisoquinoline. Among them, the direct one-step oxidation synthesis of 3,4-dihydroisoquinoline using tetrahydroisoquinoline as a raw material is a very green and efficient method. Precious metal catalysts and homogeneous catalysts have been reported to catalyze this type of reaction. However, the high cost of precious metal catalysts is not conducive to widespread application, and the selectivity of the target product 3,4-dihydroisoquinoline is not high. For example, Angelici et al. [1] The research team used gold powder as a catalyst, and the yield of 3,4-dihydroisoquinoline was only 87%. The use of homogeneous catalysts brings great difficulties to product separation, and the catalyst cannot be reused. For example, Xu et al. [2] The research team used monovalent copper to catalyze the oxidation of tetrahydroisoquinoline to generate 3,4-dihydroisoquinoline. The system used a homogeneous catalytic reaction, and the catalyst could not be reused after the reaction. In addition, adding alkaline additives to some catalytic systems is corrosive to the reaction equipment, and the separation is difficult, costly, and economical. For example, Gong et al. [3] The research team used graphene oxide as a catalyst to catalyze the oxidation of tetrahydroisoquinoline to 3,4-dihydroisoquinoline. Sodium carbonate was used as an alkaline co-catalyst in this catalytic system and the yield of 3,4-dihydroisoquinoline was only 89%. Therefore, constructing an efficient non-precious metal catalyst and catalyzing the oxidation of tetrahydroisoquinoline to 3,4-dihydroisoquinoline under relatively mild conditions without the presence of a co-catalyst has very important industrial value and research significance.

[0003] Metal organic framework (MOFs) materials are a new type of multifunctional materials. Due to their unique metal active sites, easy modification of the framework structure, and adjustable pore size, they are specifically used in catalysis, gas adsorption and separation, fluorescence sensing, magnetic materials and other fields. MOFs materials loaded with metals are also very excellent catalysts, and have achieved very good catalytic effects in photocatalysis, thermal catalysis, and electrocatalysis. At present, the use of MOFs materials in the field of photocatalysis to catalyze the oxidation of tetrahydroisoquinoline to 3,4-dihydroisoquinoline has been reported, such as Li et al. [4]The research group and Wang et al. [5] The research team used MOF-253-Ru and PMo-1 as catalysts for the catalytic oxidation of tetrahydroisoquinoline, and the corresponding 3,4-dihydroisoquinoline yields were 78.3% and 99.6%, respectively. Although the photocatalytic effect is good, it is impossible to produce continuously under sunlight in industrial production, and the cost of artificial light sources is high, and it is not as convenient as thermal catalysis. Therefore, it is very meaningful to synthesize highly stable MOFs materials for the catalytic oxidation of tetrahydroisoquinoline in thermal catalysis. Summary of the invention

[0004] The purpose of the present invention is to overcome the problems of over-oxidation and addition and repeated use of alkaline additives in the current process of oxidizing tetrahydroisoquinoline to generate 3,4-dihydroisoquinoline, and to provide a novel preparation method of a multifunctional catalyst and its application in catalyzing the oxidation of tetrahydroisoquinoline to 3,4-dihydroisoquinoline by using a three-dimensional Co-MOF constructed with 1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride and loaded with copper.

[0005] The three-dimensional Co-MOF structure of the present invention has the simplest structural unit chemical formula of {[Co2(L)(μ3-F)(H2O)3]·H2O}, which is a new metal organic framework material synthesized for the first time. Ammonium fluoride is added during the synthesis of this material, and fluoride ions are used to participate in the coordination to form a [Co4] cluster such as Figure 1 (a) There are relatively few transition metal organic framework materials synthesized using the ligands mentioned in the present invention, mainly due to the difficulty of synthesis. There are also some transition metal organic framework materials similar to the present material reported in the past. [6,7] In the Co-MOF structure of the present invention, L is an organic ligand 1,3-bis(3,5-dicarboxylic acid phenyl)imidazole, and the framework is composed of four metal ions Co(II) and two coordinated anions μ3-F such as Figure 1 (a) They are connected to form a [Co4] cluster, with the cluster as the core, coordinated with the carboxyl oxygen and water of eight ligands respectively. Each divalent cobalt has a six-coordinated coordination mode, and finally forms a three-dimensional long-range ordered framework structure. Figure 1 (b) It can be seen that the framework has The nitrogen on the imidazole ring around the pores provides basic sites for the reaction, so the reaction does not require the addition of additional alkaline additives.

[0006] The three-dimensional Co-MOF-loaded copper catalyst of the present invention adopts an impregnation reduction method to place the Co-MOF in a copper nitrate solution and stir it, then add the reducing agent glucose and continue stirring for two hours, filter it with filter paper and wash it with water, then place it in the air to dry, and then calcine it at a high temperature in a tubular furnace under an inert atmosphere for two hours to obtain the desired catalyst.

[0007] The technical solution of the present invention is as follows:

[0008] A Co-MOF-loaded copper catalyst; a metal organic framework material with a structural unit chemical formula of {[Co2(L)(μ3-F)(H2O)3]·H2O}; in the Co-MOF structure, L is an organic ligand 1,3-bis(3,5-dicarboxylic acid phenyl)imidazole, and the framework is connected by four metal ions Co(II) and two coordinated anions μ3-F to form a [Co4] cluster, with the cluster as the core and coordinated with the carboxyl oxygen and water of eight ligands respectively, and each divalent cobalt has a six-coordinated coordination mode, ultimately forming a three-dimensional long-range ordered framework structure.

[0009] The preparation method of the Co-MOF supported copper catalyst of the present invention comprises the following steps:

[0010] (1) Synthesis of Co-MOF: Add organic ligand L (1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride) and cobalt nitrate hexahydrate into a mixed solution of H2O and N,N-diethylformamide, stir evenly, place in an autoclave lined with polytetrafluoroethylene, and place in an oven at 100°C-150°C for reaction; then filter, wash with water and air-dry at room temperature to obtain a three-dimensional Co-MOF;

[0011] (2) Preparation of Cu@Co-MOF: The crystals obtained in step (1) are calcined at 200-400°C in an inert atmosphere to remove free water and coordinated water in the pores, and then copper nitrate trihydrate and water are weighed and stirred after calcination. Glucose is then added and stirred for 2-4 hours. The mixture is washed with filtered water and dried, and then calcined in an inert atmosphere in a tubular furnace to obtain the catalyst Cu@Co-MOF.

[0012] In the step (1), the molar ratio of the mixed solution of the organic ligand L (1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride), cobalt nitrate hexahydrate, ammonium fluoride, H2O and N,N-diethylformamide is preferably (1-4):4:(5-15):440:(20-50).

[0013] In the step (1), preferably, the reaction is carried out in an oven at 120° C.-150° C. for 50-200 hours, and the temperature is cooled to room temperature at a rate of 0-10° C. / h.

[0014] In the step (1), preferably in the step (2), calcination is carried out in an inert atmosphere at 200-400° C. for 1-4 hours.

[0015] In the step (1), the molar ratio of the calcined crystals, copper nitrate trihydrate, water and glucose in the step (2) is preferably (1:5):1:(3000-9300):(4-10).

[0016] In the step (1), preferably in the step (2), the calcination is carried out in an inert atmosphere in a tubular furnace for 1 h to 4 h.

[0017] The percentage of the catalyst Cu@Co-MOF is 2.0wt% to 6.0wt% Cu@Co-MOF, calculated based on the amount of added Co-MOF.

[0018] The Co-MOF-supported copper catalyst of the invention is used for catalyzing the oxidation of tetrahydroisoquinoline to generate 3,4-dihydroisoquinoline.

[0019] The Co-MOF crystal structure of the present invention belongs to the triclinic system, the P-1 space group, and the unit cell parameters are: a=7.5302(4), b=10.7759(7), c=13.7913(5), α=73.258(5)°, β=76.676(4)°, γ=74.755(5)°. The framework is connected by four Co(II) and two μ3-F- to form a [Co4] cluster, with the cluster as the core, respectively coordinating with the carboxyl oxygen and water of eight ligands, and each divalent cobalt is a six-coordinated coordination mode, which finally forms a three-dimensional long-range ordered framework structure. From the a-axis, the framework has The hole.

[0020] Further preferred conditions are as follows:

[0021] The preferred conditions in step (1) are as follows: 0.1 mmol of organic ligand L (1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride) and 0.4 mmol of cobalt nitrate hexahydrate and 0.86 mmol of ammonium fluoride are added to a mixture of 8 mL of H2O and 2 mL of N,N-diethylformamide, then stirred evenly and placed in an autoclave containing a polytetrafluoroethylene liner, and placed in an oven at 120°C for constant temperature reaction for 72 hours.

[0022] The preferred conditions in step (2) are: the crystals obtained in step (1) are calcined at 300°C in an inert atmosphere for 2 hours to remove free water and coordinated water in the pores, then 0.2 g of the calcined crystals are weighed and added to 10 mL of water containing 0.0308 g of copper nitrate trihydrate and stirred for 0.5 hours, then 0.1263 g of glucose is added and stirred for 4 hours, filtered water is washed three times, and dried, and finally placed in a tubular furnace in an inert atmosphere and calcined for 2 hours to obtain a catalyst 4.0 wt% Cu@Co-MOF

[0023] The above-synthesized heterogeneous 4.0wt% Cu@Co-MOF catalyst was used to catalyze the oxidation of tetrahydroisoquinoline to produce 3,4-dihydroisoquinoline with a yield of 95%. After the reaction was completed, the 4.0wt% Cu@Co-MOF catalyst was filtered, washed and dried for next use. The cycle experiment showed that the catalytic activity of the catalyst did not decrease significantly after repeated use.

[0024] Advantages and beneficial effects of the present invention:

[0025] The present invention synthesizes a new three-dimensional MOFs material, which has high chemical stability and thermal stability, and its thermal stability can reach 400°C. Figure 2 As shown in Figure 2, the chemical stability is reflected in the fact that after being soaked in a variety of common solvents, its powder diffraction peaks remain consistent with the original powder diffraction peaks. Figure 3 As shown, the powder diffraction peaks after being immersed in water (H2O), methanol (MeOH), ethanol (EtOH), acetonitrile (ACN), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP), 1,4-dioxane (Do), and dichloromethane (DCM) respectively. The catalyst prepared by the MOFs material loaded with copper nanoparticles has good cycle performance. After being reused five times, the powder diffraction peaks can still maintain the structure as shown in FIG. Figure 5 As shown, the yields of 3,4-dihydroisoquinoline after five uses were 95%, 97%, 94%, 92%, and 85%, respectively. Figure 4 We first used 4.0wt% Cu@Co-MOF catalyst to catalyze the oxidation of tetrahydroisoquinoline to 3,4-dihydroisoquinoline in thermal catalysis. The three-dimensional Co-MOF material has The large pores Figure 1 As shown in (b), it can adsorb reactants well and anchor copper nanoparticles. The nitrogen on the imidazole ring in the pore provides alkaline sites, so the reaction does not require the addition of alkaline additives, which is green and environmentally friendly and does not damage the equipment. The 4.0wt% Cu@Co-MOF catalyst has two catalytic active centers, copper nanoparticles and Co(II). The yield of 3,4-dihydroisoquinoline generated during the catalytic oxidation of tetrahydroisoquinoline is as high as 95%. The catalyst also avoids the use of precious metals and saves costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is the coordination mode diagram and three-dimensional structure diagram of the three-dimensional Co-MOF structure.

[0027] Figure 2 Thermogravimetric diagrams of Co-MOF and 4.0wt%Cu@Co-MOF catalysts.

[0028] Figure 3 X-ray powder diffraction (XRD) patterns of Co-MOF immersed in different solvents.

[0029] Figure 4 The cyclic result of the oxidation of tetrahydroisoquinoline to 3,4-dihydroisoquinoline catalyzed by 4.0wt% Cu@Co-MOF catalyst.

[0030] Figure 5XRD pattern of 4.0wt% Cu@Co-MOF catalyst after being reused for 5 times DETAILED DESCRIPTION

[0031] The present invention is further described below in conjunction with the accompanying drawings and embodiments. Typical embodiments are provided as references when providing specific implementations, but are not intended to limit the scope of protection of the present invention.

[0032] [Example 1]

[0033] (1) Synthesis of Co-MOF: Add organic ligand L (1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride), cobalt nitrate hexahydrate, ammonium fluoride, H2O and N,N-diethylformamide in the following amounts of 1 mmol, 4 mmol, 5 mmol, 440 mmol and 20 mmol into a polytetrafluoroethylene-lined autoclave and stir evenly. Place the autoclave in an oven at 120°C for 50 hours and then cool to room temperature at a rate of 0°C per hour. Filter directly, wash with water and air dry to obtain a three-dimensional Co-MOF.

[0034] (2) Preparation of Cu@Co-MOF: The crystals obtained in step (1) were calcined at 200°C in an inert atmosphere for 1 h to remove free water and coordinated water in the pores, and then copper nitrate trihydrate and water in the calcined crystals were weighed in amounts of 5 mmol, 1 mmol, and 9300 mmol, respectively, and stirred for 0.5 h. Then, 10 mmol of glucose was added and stirred for 2 h. The mixture was washed three times with filtered water and air-dried, and finally calcined in an inert atmosphere in a tubular furnace for 1 h to obtain a catalyst of 2.0 wt% Cu@Co-MOF (the percentage was calculated based on the amount of Co-MOF added).

[0035] (3) 10 mg of the synthesized 2.0 wt% Cu@Co-MOF heterogeneous catalyst was placed in a 20 ml branched reaction tube, 1 mmol of tetrahydroisoquinoline, 1 ml of N,N-dimethylformamide and a magnet were added thereto, and a balloon filled with O2 was connected to the mouth of the branched test tube. The filled test tube was placed in an 80°C oil bath and stirred for 100 hours. After the reaction was completed, a small amount of the reaction solution was weighed and 120 mg of the internal standard m-dichlorobenzene was added to the fixed volume. After mixing evenly, a trace amount of the solution was filtered and fed into a gas chromatograph for analysis. The yield of the target product was 91%.

[0036] [Example 2]

[0037] (1) Synthesis of Co-MOF: The organic ligand L (1,3-bis(3,5-dicarboxylic acid phenyl) imidazolium chloride), cobalt nitrate hexahydrate, ammonium fluoride, H2O and N,N-diethylformamide were added into a polytetrafluoroethylene-lined autoclave at the following ratios of 2 mmol, 4 mmol, 9 mmol, 440 mmol and 30 mmol, stirred evenly, and placed in an oven at 130°C for 72 hours, then cooled to room temperature at a rate of 5°C per hour, filtered directly, washed with water and dried. The three-dimensional Co-MOF was obtained by drying; the Co-MOF was immersed in water (H2O), methanol (MeOH), ethanol (EtOH), acetonitrile (ACN), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMA), N-methylpyrrolidone (NMP), 1,4-dioxane (Do), and dichloromethane (DCM), and then the powder diffraction peak after immersion was found to be consistent with the theoretical fitting diffraction peak, indicating that the material has good solvent stability. Figure 3 As shown,

[0038] (2) Preparation of Cu@Co-MOF: The crystals obtained in step (1) were calcined at 300°C in an inert atmosphere for 2 hours to remove free water and coordinated water in the pores. Subsequently, 2 mmol, 1 mmol, and 4300 mmol of copper nitrate trihydrate and water were weighed and stirred for 0.5 hours. Then 5 mmol of glucose was added and stirred for 2.5 hours. The mixture was washed three times with filtered water and dried. Finally, the mixture was calcined in an inert atmosphere in a tubular furnace for 2 hours to obtain a catalyst of 4.0 wt% Cu@Co-MOF (the percentage was calculated based on the amount of Co-MOF added). Co-MOF and 4.0 wt% Cu@Co-MOF were calcined to 800 degrees in a nitrogen atmosphere at a heating rate of 10 degrees per minute. It can be seen that they can both stably exist at 400 degrees. Figure 2 shown.

[0039] (3) Place 25 mg of the synthesized 4.0 wt% Cu@Co-MOF heterogeneous catalyst in a 20 ml branched reaction tube, add 1 mmol of tetrahydroisoquinoline, 1 ml of N,N-dimethylformamide and a magnet, and connect a balloon filled with O2 to the mouth of the branched test tube. Place the assembled test tube in a 90°C oil bath and stir for 4 hours. After the reaction is complete, weigh a small amount of the reaction solution and add 120 mg of the internal standard m-dichlorobenzene to the fixed volume. Mix well and filter to take a trace amount of the solution for gas chromatography and analysis. The yield of the target product is 95%. The used catalyst is centrifuged and washed with ethanol and dried for reuse. The powder diffraction peaks of the catalyst after five reuses are consistent with the theoretical fitting diffraction peaks. Figure 5 As shown, the yields of 3,4-dihydroisoquinoline after five cycles were 95%, 97%, 94%, 92%, and 85%, respectively. Figure 4 shown.

[0040] [Example 3]

[0041] (1) Synthesis of Co-MOF: The organic ligand L (1,3-bis(3,5-dicarboxylic acid phenyl) imidazolium chloride), cobalt nitrate hexahydrate, ammonium fluoride, H2O and N,N-diethylformamide were added into a polytetrafluoroethylene-lined autoclave at the following ratios of 2 mmol, 4 mmol, 9 mmol, 440 mmol and 50 mmol, stirred evenly, and placed in an oven at 150°C for 200 hours, then cooled to room temperature at a rate of 10°C per hour, filtered directly, washed with water and air-dried to obtain a three-dimensional Co-MOF;

[0042] (2) Preparation of Cu@Co-MOF: The crystals obtained in step (1) were calcined at 400°C in an inert atmosphere for 4 h to remove free water and coordinated water in the pores. Subsequently, the calcined crystals were weighed with 1 mmol, 1 mmol, and 3000 mmol of copper nitrate trihydrate and water, respectively, and stirred for 0.5 h. Then, 4 mmol of glucose was added and stirred for 4 h. The mixture was washed three times with filtered water and dried. Finally, the mixture was calcined in an inert atmosphere in a tubular furnace for 4 h to obtain a catalyst of 6.0 wt% Cu@Co-MOF (the percentage was calculated based on the amount of Co-MOF added).

[0043] (3) Place 250 mg of the synthesized 6.0 wt% Cu@Co-MOF heterogeneous catalyst in a 20 ml branched reaction tube, add 10 mmol of tetrahydroisoquinoline, 1 ml of N,N-dimethylformamide and a magnet, and connect a balloon filled with O2 to the mouth of the branched test tube. Place the filled test tube in a 110°C oil bath and stir to react at a constant temperature for 50 hours. After the reaction is completed, weigh a small amount of the reaction solution and add 120 mg of the internal standard m-dichlorobenzene to make up the volume. After mixing evenly, filter and take a trace amount of the solution for gas chromatography and analysis. The yield of the target product is 99%.

[0044] The equation for the oxidation of tetrahydroisoquinoline is as follows:

[0045]

[0046] In the above oxidation reaction, the yield of 3,4-dihydroisoquinoline is as high as 95%.

[0047] Table 1 shows that 4.0wt% Cu@Co-MOF catalyst can catalyze the oxidation of a series of tetrahydroisoquinolines to produce the corresponding 3,4-dihydroisoquinolines. It can be found that the catalyst has good universality, and the position of the substituent on the substrate molecule has no effect on the product yield, but the strong electron-withdrawing group nitro and the electron-donating groups methyl and methoxy have a certain negative effect on the product yield.

[0048] Table 1

[0049]

[0050] The optimal reaction conditions were: 1 mmol substrate, 25 mg 4.0 wt% Cu@Co-MOF catalyst, 1 atm O2, 4 h, and the yield was calculated using Shimadzu meteorological analyzer with m-dichlorobenzene as the internal standard.

[0051] The above contents are some preferred embodiments of the present invention, but the present invention should not be limited to the contents disclosed in the examples. Therefore, any equivalent or modification completed without departing from the spirit disclosed in the present invention shall fall within the scope of protection of the present invention. A small number of necessary terms are used in the description and explanation, which do not constitute a limitation of the invention.

[0052] References

[0053] [1]Angelici,RJ,Organometallic chemistry and catalysis on gold metalsurfaces.Journal of OrganometallicChemistry.2008,693(5),847-856.

[0054] [2] Huang, B., Tian, ​​H., Lin, S., Xie M., Yu,

[0055] [3] Zhang, J., Chen, S., Chen, F., Xu, W., Deng, G.-J., Gong, H., Dehydrogenation of Nitrogen Heterocycles Using Graphene Oxide as a Versatile Metal-FreeCatalyst under Air. Advanced Synthesis&Catalysis. 2017, 359(14), 2358-2363.

[0056] [4]Deng,X.,Qin,Y.,Hao,M.,Li,Z.,MOF-253-Supported Ru Complex forPhotocatalytic CO2 Reduction byCoupling with Semidehydrogenation of 1,2,3,4-Tetrahydroisoquinoline(THIQ).Inorganic Chemistry 2019,58(24),16574-16580.

[0057] [5]Liu,Y.,Ji,K.,Wang,J.,Li,H.,Zhu,X.,Ma,P.,Niu,J.,Wang,J.,EnhancedCarrier Separation inVisible-Light-Responsive Polyoxometalate-Based Metal–Organic Frameworks for Highly Efficient OxidativeCoupling of Amines.ACSApplied Materials&Interfaces 2022,14(24),27882-27890.

[0058] [6]Sen,S.,Neogi,S.,Aijaz,A.,Xu,Q.,Bharadwaj,P.K.,Construction of Non-Interpenetrated ChargedMetal–Organic Frameworks with Doubly Pillared Layers:Pore Modification and Selective Gas Adsorption.

[0059] Inorganic Chemistry 2014,53(14),7591-7598.

[0060] [7]Burgun,A.,Crees,R.S,Cole,M.L.,Doonan,C.J.,Sumby,C.J.,A 3-Ddiamondoid MOF catalyst based on insitu generated[Cu(L)2]N-heterocycliccarbene(NHC)linkers:hydroboration of CO2.ChemicalCommunications 2014,50(79),11760-11763。

Claims

1. A Co-MOF-supported copper catalyst; characterized in that: A metal organic framework material having a structural unit chemical formula of {[Co2(L)(μ3-F)(H2O)3]·H2O}; in the Co-MOF structure, L is an organic ligand 1,3-bis(3,5-dicarboxylic acid phenyl)imidazole, and the framework is connected by four divalent metal cobalt ions and two coordinated anions μ3-F to form a [Co4] cluster, which is coordinated with the carboxyl oxygen and water of eight ligands respectively with the cluster as the core, and each divalent cobalt has a six-coordinated coordination mode, and finally forms a three-dimensional long-range ordered framework structure; the preparation method comprises the following steps: (1) Synthesis of Co-MOF: Add organic ligand 1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride, cobalt nitrate hexahydrate and ammonium fluoride to a mixed solution of H2O and N,N-diethylformamide, stir evenly, place in an autoclave lined with polytetrafluoroethylene, and place in an oven at 100°C-150°C for reaction; then cool to room temperature, filter, wash with water and air-dry to obtain a three-dimensional Co-MOF; (2) Preparation of Cu@Co-MOF: The crystals obtained in step (1) are calcined at 200-400°C in an inert atmosphere to remove free water and coordinated water in the pores. The calcined crystals, copper nitrate trihydrate and water are then weighed and stirred. Glucose is then added and stirred for 2-4 hours. The mixture is washed with filtered water and dried. The mixture is then calcined in an inert atmosphere in a tubular furnace to obtain the catalyst Cu@Co-MOF.

2. The method for preparing the Co-MOF-supported copper catalyst according to claim 1, characterized in that: The following steps are involved: (1) Synthesis of Co-MOF: Add organic ligand 1,3-bis(3,5-dicarboxylic acid phenyl)imidazolium chloride, cobalt nitrate hexahydrate and ammonium fluoride to a mixed solution of H2O and N,N-diethylformamide, stir evenly, place in an autoclave lined with polytetrafluoroethylene, and place in an oven at 100°C-150°C for reaction; then cool to room temperature, filter, wash with water and air-dry to obtain a three-dimensional Co-MOF; (2) Preparation of Cu@Co-MOF: The crystals obtained in step (1) are calcined at 200-400°C in an inert atmosphere to remove free water and coordinated water in the pores. The calcined crystals, copper nitrate trihydrate and water are then weighed and stirred. Glucose is then added and stirred for 2-4 hours. The mixture is washed with filtered water and dried. The mixture is then calcined in an inert atmosphere in a tubular furnace to obtain the catalyst Cu@Co-MOF.

3. The preparation method according to claim 2, characterized in that: In step (1), the molar ratio of the organic ligand 1,3-bis(3,5-dicarboxylic acid phenylimidazolium chloride), cobalt nitrate hexahydrate, ammonium fluoride, H2O and N,N-diethylformamide is (1-4):4:(5-15):440:(20-50).

4. The preparation method according to claim 2, characterized in that: In step (1), the reaction is carried out in an oven at 120° C.-150° C. for 50-200 hours; and the temperature is cooled to room temperature at a rate of 5-10° C. / h.

5. The preparation method according to claim 2, characterized in that: In step (2), calcination is carried out at 200-400° C. in an inert atmosphere for 1-4 h.

6. The preparation method according to claim 2, characterized in that: The molar ratio of the calcined crystals, copper nitrate trihydrate, water and glucose in step (2) is (1:5):1:(3000-9300):(4-10).

7. The preparation method according to claim 2, characterized in that: In step (2), the mixture is placed in a tubular furnace and calcined under an inert atmosphere for 1 h to 4 h.

8. The Co-MOF-supported copper catalyst of claim 1 is used to catalyze the oxidation of tetrahydroisoquinoline to produce 3,4-dihydroisoquinoline.

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