Bimetal MOF (Metal Organic Framework) material catalyst as well as preparation method and application thereof in catalyzing cyclohexanone oxidation to prepare epsilon-caprolactone

Abstract

The invention belongs to the technical field of chemical materials, and particularly discloses a bimetallic MOF material catalyst, a preparation method thereof and application of the bimetallic MOF material catalyst in catalysis of cyclohexanone oxidation for preparation of epsilon-caprolactone. The preparation method comprises the following steps: mixing a copper source, a cerium source, trimesic acid and a solvent, and carrying out crystallization treatment to prepare the copper-cerium bimetallic MOF material catalyst. Research is carried out on preparation of epsilon-caprolactone through catalytic oxidation of cyclohexanone in an O2 / aldehyde system, the copper-cerium bimetallic MOF material catalyst with high catalytic performance is prepared by applying a simple hydrothermal / solvothermal method, high-selectivity preparation of epsilon-caprolactone through catalytic oxidation of cyclohexanone is realized, the dosage of a pro-oxidant benzaldehyde is reduced, and the utilization rate of the pro-oxidant benzaldehyde is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical materials, and in particular to a bimetallic MOF material catalyst, a preparation method thereof, and application thereof in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone. Background Art

[0002] As a new polyester monomer with a wide range of uses, ε-caprolactone is mainly used to produce high-performance polymers, such as thermoplastic polycaprolactone (PCL), polycaprolactone polyols and their derivatives. These polymers have shown broad application prospects in many fields such as medicine, packaging, textiles, and automobiles due to their good biodegradability, biocompatibility, and mechanical properties. In recent years, with the increase in global demand for environmentally friendly materials, the market for ε-caprolactone as a monomer for synthesizing biodegradable plastic PCL has shown a rapid growth trend.

[0003] There are four main synthetic processes reported for the synthesis of ε-caprolactone: 1,6-hexanediol dehydrogenation, 6-hydroxycaproic acid intramolecular condensation, adipic acid acidification, and cyclohexanone oxidation. Among them, the Baeyer-Villiger (BV) oxidation rearrangement reaction of cyclohexanone is the mainstream process for industrial production. According to the different raw materials, it can be divided into peroxyacid oxidation, H 2 O 2 Oxidation method, O 2 Oxidation method and biological oxidation method. The process of preparing ε-caprolactone by oxidation of cyclohexanone with peroxy acid BV is the most mature and is the method for industrial production of ε-caprolactone at home and abroad. However, the high concentration of hydrogen peroxide required for the preparation of peroxy acid in the production process and the peroxy acid itself in storage, transportation and reaction all pose great safety hazards, and a certain amount of waste acid is produced as a by-product.

[0004] In recent years, O 2 The method of preparing ε-caprolactone by oxidizing cyclohexanone with aldehydes as oxidants and co-oxidants has attracted more and more attention. The method has mild reaction conditions, safe raw materials, and can be used with O 2 Using metal phthalocyanine as an oxidant is in line with the concept of "green chemistry". The catalysts currently reported in research mainly include metal organic ligand catalysts, composite metal oxide catalysts, molecular sieve supported catalysts and non-metallic catalysts. Limited by the weak oxidizing ability of molecular oxygen, most of the catalysts currently reported require a higher molar ratio of benzaldehyde to cyclohexanone to obtain a higher ε-caprolactone yield, and the utilization efficiency of benzaldehyde is low. Patent CN104003971B uses metal phthalocyanine as a catalyst, and the ε-caprolactone yield can reach up to 92.6%. However, the reaction time of this system is as long as 12 hours. Patent CN115445601B invented a supported SiO 2 @M x O y —TiO2 (M x O y For CuO, SnO 2 or Fe 2 O 3 One or more) catalysts, wherein SiO 2 @Fe 2 O 3 / CuO—TiO 2 When used as a catalyst, the highest yield of ε-caprolactone is 99.2%. The preparation process of this type of catalyst is relatively complicated.

[0005] Therefore, the development of 2 The development of an efficient catalyst for the oxidative rearrangement of cyclohexanone BV to prepare ε-caprolactone in a cyclohexanone / aldehyde system, while obtaining a high yield of ε-caprolactone and reducing the amount of the co-oxidant benzaldehyde and improving the utilization rate of aldehyde, is a difficult problem to be solved in this field. Summary of the invention

[0006] In view of this, the present invention provides a bimetallic MOF material catalyst, a preparation method thereof and application in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone, so as to solve the problems of complex preparation of existing catalysts, high aldehyde-ketone feed ratio required for the reaction to obtain a high ε-caprolactone yield and low aldehyde utilization rate.

[0007] In order to achieve the above object, the present invention adopts the following technical solution:

[0008] A method for preparing a bimetallic MOF material catalyst comprises the following steps:

[0009] A copper source, a cerium source, trimesic acid and a solvent are mixed and crystallized to obtain a bimetallic MOF material catalyst.

[0010] Preferably, the molar ratio of the copper source to the cerium source is 1:10 to 80;

[0011] The copper source includes one or more of copper nitrate, copper chloride and copper sulfate;

[0012] The cerium source includes one or more of cerium nitrate, cerium chloride and cerium sulfate.

[0013] Preferably, the molar ratio of the cerium source to trimesic acid is 1:1-3.

[0014] Preferably, the solvent comprises N,N-dimethylformamide and / or water;

[0015] The volume ratio of N,N-dimethylformamide and water is 0-4:4-0.

[0016] Preferably, the molar volume ratio of the cerium source to the solvent is 1 mmol:4-16 mL.

[0017] Preferably, the temperature of the crystallization treatment is 70 to 150° C., and the time of the crystallization treatment is 3 to 24 hours.

[0018] Another object of the present invention is to provide a method for preparing a bimetallic MOF material catalyst and obtain a bimetallic MOF material catalyst.

[0019] Another object of the present invention is to provide an application of the bimetallic MOF material catalyst in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone.

[0020] Preferably, the application method comprises the following steps:

[0021] Cyclohexanone, benzaldehyde, a bimetallic MOF material catalyst and a reaction solvent are mixed, oxygen is introduced, and an oxidation reaction is carried out to obtain ε-caprolactone.

[0022] Preferably, the molar ratio of cyclohexanone to benzaldehyde is 1:0.5-2.5; the mass volume ratio of cyclohexanone, bimetallic MOF material catalyst and reaction solvent is 2g:0.05-1g:10-40mL;

[0023] The reaction solvent includes one or more of 1,2-dichloroethane, ethyl acetate, acetonitrile, methanol and ethanol;

[0024] The temperature of the oxidation reaction is 30-80° C., and the time of the oxidation reaction is 1-12 hours.

[0025] It can be seen from the above technical solution that compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention utilizes the special structure of MOF materials and uses a simple hydrothermal / solvothermal method to prepare a bimetallic MOF material catalyst with uniformly dispersed cerium and copper metals in one step. Since the copper species and cerium species of different valence states in the catalyst have a synergistic effect, cyclohexanone can be effectively activated and benzaldehyde can be oxidized to generate peroxyacid intermediates, thereby increasing the catalytic reaction rate; and it is conducive to the selective generation of ε-caprolactone. Finally, O 2 The catalytic oxidation of cyclohexanone BV in a catalytic / aldehyde auxiliary system to efficiently prepare ε-caprolactone reduces the amount of co-oxidant benzaldehyde and improves the utilization rate of benzaldehyde. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0028] Figure 1 XRD characterization diagrams of the catalysts prepared in Example 1 of the present invention and Comparative Example 1 (Intensity, degree);

[0029] Figure 2 Infrared (FT-IR) characterization diagram (Transmittance - transmittance, Wavenumber - wavenumber) of the catalyst prepared in Example 1 of the present invention and Comparative Example 1;

[0030] Figure 3 The transmission electron microscope images of the catalysts prepared in Example 1 and Comparative Example 1 of the present invention are shown in FIG. Figure 3 (a) is a TEM lattice image of the catalyst prepared in Comparative Example 1 of the present invention; Figure 3 (b) is a TEM lattice image of the catalyst prepared in Example 1 of the present invention;

[0031] Figure 4 This is an EDS electron image of the catalyst prepared in Example 1 of the present invention;

[0032] Figure 5 This is the EDS element distribution diagram of the bimetallic MOF material catalyst prepared in Example 1 of the present invention. DETAILED DESCRIPTION

[0033] The present invention provides a method for preparing a bimetallic MOF material catalyst, comprising the following steps:

[0034] A copper source, a cerium source, trimesic acid and a solvent are mixed and crystallized to obtain a bimetallic MOF material catalyst.

[0035] In the present invention, the molar ratio of the copper source to the cerium source is 1:10 to 80, preferably 1:20 to 60, more preferably 1:30 to 50, and most preferably 1:40;

[0036] In the present invention, the copper source includes one or more of copper nitrate, copper chloride and copper sulfate.

[0037] In the present invention, the cerium source includes one or more of cerium nitrate, cerium chloride and cerium sulfate.

[0038] In the present invention, the copper source and the cerium source also include hydrates corresponding to the disclosed compounds.

[0039] In the present invention, the molar ratio of the cerium source to trimesic acid is 1:1-3, preferably 1:1-2.5, more preferably 1:1-2, and most preferably 1:1.

[0040] In the present invention, the solvent includes N,N-dimethylformamide and / or water;

[0041] The volume ratio of N,N-dimethylformamide to water is 0-4:4-0 (not 0 at the same time), preferably 1-3:3-1, more preferably 2-3:2-1, and most preferably 3:1.

[0042] In the present invention, when N,N-dimethylformamide and water exist in the solvent at the same time, the preparation method of the bimetallic MOF material catalyst is preferably: first, the copper source, the cerium source, trimesic acid and N,N-dimethylformamide are mixed, and then water is added to mix, and after mixing evenly, crystallization treatment is performed to obtain the bimetallic MOF material catalyst; when the solvent is only water, the addition of N,N-dimethylformamide is omitted in the preparation process; when the solvent is only N,N-dimethylformamide, the addition of water is omitted in the preparation process, and the mixing operation after adding water is also omitted.

[0043] In the present invention, N, N-dimethylformamide has good solubility and dispersibility for metal salts and trimesic acid ligands. When the content of DMF (N, N-dimethylformamide) is high, the reaction generally proceeds at a relatively mild and slow rate, which helps to control the growth direction and rate of the crystal, accurately control the reaction process and synthesize high-quality products, so that the MOF material tends to form a specific morphology (such as regular octahedron, cube, etc.), which helps to form a more regular and orderly pore structure with a relatively large specific surface area; the addition of polar molecular water can enhance the activity of the reactant ions, accelerate diffusion, and accelerate the reaction rate, but it can also make the reaction environment relatively unstable, which is easy to cause irregular growth, crystal surface defects, low crystallinity and other problems in the crystal growth process. Excessive water may destroy the originally orderly pore structure formation process, resulting in collapse and blockage of the pores, thereby reducing the specific surface area of ​​the product. By rationally regulating the ratio of the two, many properties such as the crystallinity, morphology, specific surface area and reaction rate of the product can be optimized in a targeted manner.

[0044] In the present invention, the molar volume ratio of the cerium source to the solvent is 1 mmol:4-16 mL, preferably 1 mmol:5-15 mL, more preferably 1 mmol:8-12 mL, and further preferably 1 mmol:10 mL.

[0045] In the present invention, the temperature of the crystallization treatment is 70-150°C, specifically 80°C, 90°C, 100°C, 120°C, and 140°C; the time of the crystallization treatment is 3-24h, specifically 5h, 6h, 8h, 10h, 12h, 15h, 18h, and 20h.

[0046] The present invention also provides a bimetallic MOF material catalyst prepared by a method for preparing a bimetallic MOF material catalyst.

[0047] The present invention also provides an application of the bimetallic MOF material catalyst in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone.

[0048] In the present invention, the application method comprises the following steps:

[0049] Cyclohexanone, benzaldehyde, a bimetallic MOF material catalyst and a reaction solvent are mixed, oxygen is introduced, and an oxidation reaction is carried out to obtain ε-caprolactone.

[0050] In the present invention, the molar ratio of cyclohexanone to benzaldehyde is 1:0.5-2.5, preferably 1:1.5-2; the mass volume ratio of cyclohexanone, bimetallic MOF material catalyst and reaction solvent is 2g:0.05-1g:10-40mL, preferably 2g:0.1-0.8g:15-35mL, further preferably 2g:0.4-0.6g:20-30mL, and further preferably 2g:0.5g:25mL.

[0051] In the present invention, the reaction solvent includes one or more of 1,2-dichloroethane, ethyl acetate, acetonitrile, methanol and ethanol.

[0052] In the present invention, the temperature of the oxidation reaction is 30-80°C, specifically 40°C, 50°C, 60°C, 70°C; the time of the oxidation reaction is 1-12h, specifically 2h, 4h, 5h, 6h, 8h, 10h.

[0053] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] Example 1

[0055] Weigh 0.024 g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 )3 6H 2 O and 0.84g of trimesic acid were placed in a beaker, 24mL of N,N-dimethylformamide (DMF) was added thereto, and the mixture was stirred at room temperature for 10min to fully dissolve, and then 8mL of deionized water was added thereto. After mixing evenly, the mixture was transferred to a 100mL hydrothermal kettle and crystallized at 100°C for 12h. After crystallization, the solid was separated and washed with DMF and ethanol several times, and the precipitate was dried in an oven at 60°C to obtain Cu-Ce-MOF (bimetallic MOF material catalyst), in which the molar ratio of Cu to Ce was 1:40.

[0056] The above MOF material was applied to the preparation of ε-caprolactone by oxidation of cyclohexanone BV. The steps were as follows: 2 g cyclohexanone, 3.244 g benzaldehyde, 0.2 g of the above catalyst, and 20 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 50 °C under stirring, and then O was blown into the reactor. 2 , react for 6 hours. After the reaction is completed, the content of each component in the reaction product is quantitatively analyzed by gas chromatography internal standard method and used to calculate the cyclohexanone conversion rate, benzaldehyde conversion rate, and ε-caprolactone yield; the utilization rate of benzaldehyde is the ratio of the molar amount of ε-caprolactone generated by the reaction to the molar amount of converted benzaldehyde. It is calculated that the cyclohexanone conversion rate of this embodiment is 86.7%, the ε-caprolactone yield is 84.8%, and the benzaldehyde utilization rate is 0.67.

[0057] Comparative Example 1

[0058] Omit the Cu(NO 3 ) 2 ·3H 2 O was added, and the other preparation conditions were the same as those in Example 1 to obtain a Ce-MOF material catalyst. The catalyst was applied to cyclohexanone BV oxidation to prepare ε-caprolactone according to the method and reaction conditions of Example 1. The conversion rate of cyclohexanone was 85.0%, the yield of ε-caprolactone was 75.3%, and the utilization rate of benzaldehyde was 0.55.

[0059] Comparative Example 2

[0060] Omit Ce(NO in Example 1 3 ) 3 6H 2 O was added, and the other preparation conditions were the same as those in Example 1 to obtain a Cu-MOF material catalyst. The catalyst was applied to cyclohexanone BV oxidation to prepare ε-caprolactone according to the method and reaction conditions of Example 1. The conversion rate of cyclohexanone was 90.9%, the yield of ε-caprolactone was 76.7%, and the utilization rate of benzaldehyde was 0.54.

[0061] Experimental Example 1

[0062] The MOF materials prepared in Example 1 and Comparative Example 1 were subjected to relevant tests (the MOF material obtained in Example 1 was recorded as Cu-Ce-MOF, and the MOF material obtained in Comparative Example 1 was recorded as Ce-MOF). The XRD characterization diagrams of the MOF materials prepared in Example 1 and Comparative Example 1 are shown in FIG. Figure 1 As shown, through Figure 1 It can be seen that the two materials have characteristic diffraction peaks belonging to Ce-MOF at 2θ=8.6°, 10.7°, 13.7° and 18.2°, which confirms the successful preparation of Ce-MOF materials. After the introduction of a small amount of Cu element, the position and relative intensity of these characteristic peaks did not change significantly, indicating that the doping of Cu did not significantly change the original crystal framework structure of Ce-MOF, and Cu-Ce-MOF maintained the basic skeleton characteristics of the material.

[0063] Infrared characterization pictures Figure 2 As shown, through Figure 2 It can be seen that the FT-IR spectra of Ce-MOF and Cu-Ce-MOF have a peak at 523.0 cm -1 The characteristic absorption peaks corresponding to the stretching vibration of Ce-O bonds appeared at 725.1 cm -1 A new characteristic peak appeared at 1368.8cm -1 and 1543.5cm -1 The characteristic peaks at 1631.3 cm-1 are attributed to the symmetric stretching vibration and asymmetric stretching vibration of the OCO bond in the ligand trimesic acid. -1 The characteristic peaks appearing at are attributed to the vibration of the C=O bond in the ligand trimesic acid, and the appearance of these characteristic peaks further verifies the integrity of the metal organic framework structure. Therefore, Example 1 of the present invention successfully constructs the Ce-MOF skeleton structure and realizes the effective doping of Cu species in MOF, forming a bimetallic Ce-Cu-MOF material.

[0064] The transmission electron microscopy spectra of the catalysts prepared in Example 1 and Comparative Example 1 of the present invention are as follows: Figure 3 As shown, Figure 3 (a) is a TEM lattice image of the Ce-MOF catalyst prepared in Comparative Example 1 of the present invention; Figure 3 (b) is a TEM lattice image of the Ce-Cu-MOF catalyst prepared in Example 1 of the present invention. It can be seen from the lattice image that the lattice spacing is significantly increased after the incorporation of Cu, indicating the successful introduction of Cu species.

[0065] The EDS electron image of the catalyst prepared in Example 1 of the present invention is as follows: Figure 4 As shown, through Figure 4 It can be seen that the synthesized Cu-Ce-MOF sample presents a typical rod-like morphology, and the EDS electron image shows that the four elements C, O, Ce, and Cu in the sample all have a uniform spatial distribution.

[0066] The EDS element distribution diagram of the Cu-Ce-MOF catalyst prepared in Example 1 of the present invention is as follows: Figure 5 As shown, through Figure 5 It can be further seen that C, O, Ce, and Cu are uniformly distributed in the bimetallic MOF material catalyst prepared in the present invention.

[0067] Example 2

[0068] Weigh 0.097g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 ) 3 6H 2 O and 0.84 g of trimesic acid were placed in a beaker, and the subsequent preparation steps were the same as the catalyst preparation conditions in Example 1 to obtain Cu-Ce-MOF, wherein the molar ratio of Cu to Ce was 1:10.

[0069] The above MOF material was applied to the preparation of ε-caprolactone by oxidation of cyclohexanone BV. The steps were as follows: 2 g cyclohexanone, 3.244 g benzaldehyde, 0.15 g catalyst, and 15 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 45 °C under stirring, and then O was blown into the reactor. 2 , react for 7h. The conversion rate of cyclohexanone was calculated to be 91.9%, the yield of ε-caprolactone was 85.5%, and the utilization rate of benzaldehyde was 0.60.

[0070] Example 3

[0071] Weigh 0.012g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 ) 3 6H 2 O and 0.84 g of trimesic acid were placed in a beaker, and the subsequent preparation steps were the same as the catalyst preparation conditions in Example 1 to obtain Cu-Ce-MOF, wherein the molar ratio of Cu to Ce was 1:80.

[0072] The Cu-Ce-MOF material was applied to the preparation of ε-caprolactone by BV oxidation of cyclohexanone. The steps were as follows: 2 g cyclohexanone, 4.325 g benzaldehyde, 0.2 g catalyst, and 20 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 60 °C under stirring, and then O was blown into the reactor.2 , react for 6 hours. The conversion rate of cyclohexanone, the yield of ε-caprolactone, and the utilization rate of benzaldehyde were calculated to be 96.2%, 90.9%, and 0.49, respectively.

[0073] Example 4

[0074] Weigh 0.024 g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 ) 3 6H 2 O and 0.84g of trimesic acid were placed in a beaker, 32mL of deionized water was added thereto, stirred at room temperature for 10min, and after being fully dissolved, transferred to a 100mL hydrothermal kettle and crystallized at 100°C for 12h. After crystallization, the solid was separated and washed with DMF and ethanol several times, and the precipitate was placed in an oven at 60°C to dry to obtain Cu-Ce-MOF, in which the molar ratio of Cu to Ce was 1:40, and the ratio of DMF to deionized water was 0:4.

[0075] The Cu-Ce-MOF material was applied to the preparation of ε-caprolactone by BV oxidation of cyclohexanone. The steps were as follows: 2 g cyclohexanone, 4.325 g benzaldehyde, 0.3 g catalyst, and 20 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 60 °C under stirring, and then O was blown into the reactor. 2 , react for 5 hours. The conversion rate of cyclohexanone, the yield of ε-caprolactone, and the utilization rate of benzaldehyde were calculated to be 98.4%, 94.6%, and 0.51, respectively.

[0076] Example 5

[0077] Weigh 0.024 g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 ) 3 6H 2 O and 0.84g trimesic acid were placed in a beaker, 32mL DMF was added thereto, stirred at room temperature for 10min, and after being fully dissolved, transferred to a 100mL hydrothermal kettle and crystallized at 100°C for 12h. After crystallization, the solid was separated and washed with DMF and ethanol several times, and the precipitate was placed in an oven at 60°C to dry to obtain Cu-Ce-MOF, in which the molar ratio of Cu to Ce was 1:40, and the ratio of DMF to deionized water was 4:0.

[0078] The Cu-Ce-MOF material was applied to the preparation of ε-caprolactone by BV oxidation of cyclohexanone. The steps were as follows: 2 g cyclohexanone, 3.460 g benzaldehyde, 0.2 g catalyst, and 25 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 45 °C under stirring, and then O was blown into the reactor. 2 , react for 6 hours. The conversion rate of cyclohexanone, the yield of ε-caprolactone, and the utilization rate of benzaldehyde were calculated to be 93.2%, 90.7%, and 0.60, respectively.

[0079] Example 6

[0080] Weigh 0.024 g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 ) 3 6H 2 O and 0.84g of trimesic acid were placed in a beaker, 24mL of N,N-dimethylformamide (DMF) was added thereto, and the mixture was stirred at room temperature for 10min to fully dissolve, and then 8mL of deionized water was added thereto. After mixing evenly, the mixture was transferred to a 100mL hydrothermal kettle and crystallized at 100°C for 6h. After crystallization, the solid was separated and washed several times with DMF and ethanol, and the precipitate was dried in an oven at 60°C to obtain Cu-Ce-MOF, in which the molar ratio of Cu to Ce was 1:40, the crystallization temperature was 100°C, and the crystallization time was 6h.

[0081] The MOF material was applied to cyclohexanone BV oxidation to prepare ε-caprolactone according to the method and reaction conditions of Example 1. It was calculated that the cyclohexanone conversion rate was 92.5%, the ε-caprolactone yield was 92.4%, and the benzaldehyde utilization rate was 0.67.

[0082] Example 7

[0083] Weigh 0.024 g Cu(NO 3 ) 2 ·3H 2 O, 1.72 g Ce(NO 3 ) 3 6H 2 O and 0.84g of trimesic acid were placed in a beaker, 24mL of N,N-dimethylformamide (DMF) was added thereto, and the mixture was stirred at room temperature for 10min to fully dissolve, and then 8mL of deionized water was added thereto. After mixing evenly, the mixture was transferred to a 100mL hydrothermal kettle and crystallized at 70°C for 18h. After crystallization, the solid was separated and washed with DMF and ethanol several times, and the precipitate was dried in an oven at 60°C to obtain Cu-Ce-MOF, in which the molar ratio of Cu to Ce was 1:40, the crystallization temperature was 70°C, and the crystallization time was 18h.

[0084] The above MOF material was applied to the preparation of ε-caprolactone by oxidation of cyclohexanone BV. The steps were as follows: 2 g cyclohexanone, 4.325 g benzaldehyde, 0.2 g catalyst, and 30 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 40 °C under stirring, and then O was blown into the reactor. 2 , react for 8 hours. The conversion rate of cyclohexanone, the yield of ε-caprolactone, and the utilization rate of benzaldehyde were calculated to be 98.5%, 95.6%, and 0.51, respectively.

[0085] Example 8

[0086] The MOF material prepared in Example 6 was used to oxidize cyclohexanone BV to prepare ε-caprolactone. The steps were as follows: 2 g cyclohexanone, 4.325 g benzaldehyde, 0.2 g catalyst, and 20 mL acetonitrile were added to the reactor in sequence. The temperature was raised to 50 °C under stirring, and then O was blown into the reactor. 2 , react for 8 hours. The conversion rate of cyclohexanone, the yield of ε-caprolactone, and the utilization rate of benzaldehyde were calculated to be 98.1%, 91.3%, and 0.48, respectively.

[0087] Example 9

[0088] Weigh 0.025g CuSO 4 ·5H 2 O, 2.27 g Ce 2 (SO 4 ) 3 8H 2 O and 0.42g of trimesic acid were placed in a beaker, 24mL of N,N-dimethylformamide (DMF) was added thereto, and the mixture was stirred at room temperature for 10min to fully dissolve, and then 8mL of deionized water was added thereto. After mixing evenly, the mixture was transferred to a 100mL hydrothermal kettle and crystallized at 100°C for 6h. After crystallization, the solid was separated and washed with DMF and ethanol several times. The precipitate was dried in an oven at 60°C to obtain Cu-Ce-MOF, in which the copper source and cerium source were: CuSO 4 ·5H 2 O.Ce 2 (SO 4 ) 3 8H 2 O.

[0089] The Cu-Ce-MOF material was applied to the BV oxidation of cyclohexanone to prepare ε-caprolactone. The steps were as follows: 2 g cyclohexanone, 4.325 g benzaldehyde, 0.2 g catalyst, and 15 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 50 °C under stirring, and then O was blown into the reactor. 2 , react for 7h. The conversion rate of cyclohexanone, the yield of ε-caprolactone and the utilization rate of benzaldehyde were calculated to be 93.6%, 90.6% and 0.50, respectively.

[0090] Example 10

[0091] Weigh 0.024Cu(NO 3 ) 2 ·3H 2 O, 1.49gCeCl 3 7H 2 O and 1.26g of trimesic acid were placed in a beaker, 24mL of N,N-dimethylformamide (DMF) was added, and it was stirred at room temperature for 10min to fully dissolve. Then 8mL of deionized water was added, and after mixing evenly, it was transferred to a 100mL hydrothermal kettle and crystallized at 100℃ for 6h. After crystallization, the solid was separated and washed with DMF and ethanol several times. The precipitate was placed in an oven at 60℃ and dried to obtain Cu-Ce-MOF, in which the cerium source was CeCl 3 7H 2 O.

[0092] The Cu-Ce-MOF material was applied to the preparation of ε-caprolactone by BV oxidation of cyclohexanone. The steps were as follows: 2 g cyclohexanone, 4.325 g benzaldehyde, 0.1 g catalyst, and 20 mL 1,2-dichloroethane were added to the reactor in sequence. The temperature was raised to 40 °C under stirring, and then O was blown into the reactor. 2 , react for 8 hours. The conversion rate of cyclohexanone, the yield of ε-caprolactone, and the utilization rate of benzaldehyde were calculated to be 97.6%, 94.8%, and 0.51, respectively.

[0093] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0094] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a bimetallic MOF material catalyst, characterized in that: The steps include: A copper source, a cerium source, trimesic acid and a solvent are mixed and crystallized to obtain a bimetallic MOF material catalyst.

2. The method for preparing a bimetallic MOF material catalyst according to claim 1, characterized in that: The molar ratio of the copper source to the cerium source is 1:10 to 80; The copper source includes one or more of copper nitrate, copper chloride and copper sulfate; The cerium source includes one or more of cerium nitrate, cerium chloride and cerium sulfate.

3. The method for preparing a bimetallic MOF material catalyst according to claim 2, characterized in that: The molar ratio of the cerium source to trimesic acid is 1:1-3.

4. A method for preparing a bimetallic MOF material catalyst according to any one of claims 1 to 3, characterized in that: The solvent includes N,N-dimethylformamide and / or water; The volume ratio of N,N-dimethylformamide and water is 0-4:4-0.

5. The method for preparing a bimetallic MOF material catalyst according to claim 4, characterized in that: The molar volume ratio of the cerium source to the solvent is 1 mmol:4-16 mL.

6. The method for preparing a bimetallic MOF material catalyst according to claim 5, characterized in that: The temperature of the crystallization treatment is 70 to 150° C., and the time of the crystallization treatment is 3 to 24 hours.

7. A bimetallic MOF material catalyst prepared by the method for preparing a bimetallic MOF material catalyst according to any one of claims 1 to 6.

8. Use of the bimetallic MOF material catalyst according to claim 7 in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone.

9. Use of the bimetallic MOF material catalyst according to claim 8 in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone, characterized in that: The method of application comprises the following steps: Cyclohexanone, benzaldehyde, a bimetallic MOF material catalyst and a reaction solvent are mixed, oxygen is introduced, and an oxidation reaction is carried out to obtain ε-caprolactone.

10. Use of the bimetallic MOF material catalyst according to claim 9 in catalyzing the oxidation of cyclohexanone to prepare ε-caprolactone, characterized in that: The molar ratio of cyclohexanone to benzaldehyde is 1:0.5-2.5; the mass volume ratio of cyclohexanone, bimetallic MOF material catalyst and reaction solvent is 2g:0.05-1g:10-40mL; The reaction solvent includes one or more of 1,2-dichloroethane, ethyl acetate, acetonitrile, methanol and ethanol; The temperature of the oxidation reaction is 30-80° C., and the time of the oxidation reaction is 1-12 hours.

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