Modified copper-based metal organic framework material, preparation method thereof and application of modified copper-based metal organic framework material in catalysis of cyclohexanone oxidation rearrangement to prepare epsilon-caprolactone

Abstract

The invention provides a modified copper-based metal organic framework material, a preparation method thereof and application of the modified copper-based metal organic framework material in catalyzing cyclohexanone oxidation rearrangement to prepare epsilon-caprolactone, and belongs to the technical field of material preparation and chemical engineering. A crystallization method and a post-synthesis modification method are combined, a halogen atom (Cl, Br or I) is used for replacing a hydrogen atom of a meta-position carbon-hydrogen bond of a benzene ring in a trimesic acid ligand, and the halogen modified copper-based metal organic framework material is prepared and applied to catalysis of a Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone under an oxygen-benzaldehyde system to prepare epsilon-caprolactone. The catalyst is simple in preparation condition, high in catalytic activity, excellent in cycling stability, high in caprolactone selectivity in reaction and high in utilization rate of sacrificial agent benzaldehyde.

Description

Technical Field

[0001] The invention relates to the technical field of material preparation and chemical engineering, and in particular to a modified copper-based metal organic framework material and a preparation method thereof, and application thereof in catalyzing the oxidative rearrangement of cyclohexanone to prepare epsilon-caprolactone. Background Art

[0002] As an important chemical intermediate, ε-caprolactone is mainly used to synthesize polycaprolactone, polycaprolactone polyol, and polycaprolactone polyurethane. At present, the industry mainly adopts the Baeyer-Villiger (BV) oxidation rearrangement process of cyclohexanone to prepare ε-caprolactone, and the oxidant used is peroxy acid (usually peracetic acid or peroxypropionic acid). The high concentration of hydrogen peroxide required for the preparation of peroxy acid in the industrial production process, as well as the peroxy acid itself, have great safety hazards in storage, transportation and reaction, and a certain amount of waste acid is produced as a by-product.

[0003] Compared with peroxyacid, the cyclohexanone BV oxidative rearrangement process using oxygen or air as oxidant and aldehydes (usually benzaldehyde) as sacrificial agent has the advantages of safe and easy-to-obtain raw materials, mild reaction conditions, and high reaction selectivity. Patents CN102391238A, CN103467434A, CN103450144A, and CN104003971A use metal phthalocyanine and metal porphyrin as catalysts respectively. The reaction conditions are mild, but they are limited by the high cost of catalyst use, and the catalyst also has the defects of poor stability and difficulty in recycling. Patent CN105237507A uses divalent copper magnetic nanoparticles Fe 3 O 4 Balls and TiO 2 -P25 is coated on MCM-41 as a catalyst. Patent CN104592192A uses cupric chloride or supported cupric chloride as a catalyst. Both can completely convert cyclohexanones in the catalytic reaction. However, the preparation process of the high-performance catalyst involved is relatively complicated and is limited by the weak oxidizing ability of molecular oxygen. Most catalysts require a larger molar ratio of benzaldehyde to cyclohexanone to obtain a higher ε-caprolactone yield. The utilization efficiency of the sacrificial agent benzaldehyde is low. Summary of the invention

[0004] The purpose of the present invention is to provide a modified copper-based metal organic framework material and a preparation method thereof and application thereof in catalyzing the oxidative rearrangement of cyclohexanone to prepare epsilon-caprolactone.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions: The present invention provides a method for preparing a modified copper-based metal organic framework material, comprising the following steps: Mixing copper metal salt, mesitylene-3-benzoic acid and a first solvent to perform a crystallization reaction to obtain a copper-based metal organic framework material; Calcination activation of the copper-based metal organic framework material to obtain an activated copper-based metal organic framework material; The activated copper-based metal organic framework material, the modifier and the second solvent are mixed to carry out a modification reaction to obtain a modified copper-based metal organic framework material; The modifier includes tetrabutylammonium chloride, ammonium chloride, tetrabutylammonium bromide, ammonium bromide, tetrabutylammonium iodide or ammonium iodide, and the mass ratio of the copper-based metal organic framework material to the modifier is 1:0.6~1; the temperature of the modification reaction is 25~60°C, and the time is 20~28 h.

[0006] Preferably, the copper metal salt comprises one or more of copper nitrate trihydrate, copper sulfate, copper acetate and copper chloride; the molar ratio of the copper metal salt to trimesic acid is 1:1 to 3:1; The first solvent includes one or more of N,N-dimethylformamide, methanol, ethanol and water.

[0007] Preferably, the crystallization reaction temperature is 80-120° C. and the time is 12-24 h.

[0008] Preferably, the calcination activation temperature is 150-200° C. and the time is 8-16 h.

[0009] Preferably, the second solvent includes methanol, ethanol or water.

[0010] The invention provides a modified copper-based metal organic framework material prepared by the above preparation method.

[0011] The present invention provides an application of the modified copper-based metal organic framework material in catalyzing the oxidative rearrangement of cyclohexanone to prepare ε-caprolactone. The application method comprises the following steps: mixing benzaldehyde, cyclohexanone, the modified copper-based metal organic framework material and an organic solvent, introducing oxygen or air, and performing an oxidation reaction to obtain ε-caprolactone.

[0012] Preferably, the molar ratio of benzaldehyde to cyclohexanone is 0.5-2.5:1; and the organic solvent includes 1,2-dichloroethane, 1,4-dioxane, acetonitrile or ethyl acetate.

[0013] Preferably, the pressure of the oxygen or air is 0.2-0.6 MPa; the temperature of the oxidation reaction is 40-70° C., and the time is 4-9 h.

[0014] Beneficial effects of the present invention: The present invention mixes copper metal salt, mesitylene tribenzoic acid and a first solvent, obtains a copper-based metal organic framework material through a crystallization reaction, and then continues to roast and activate it, mixes the activated copper-based metal organic framework material, a halogen-containing modifier and a second solvent, and performs a modification reaction to obtain a modified copper-based metal organic framework material.

[0015] The present invention replaces the hydrogen atom on the meta-carbon of the benzene ring in the trimesic acid ligand with halogen (Cl, Br, I), so that the ligand undergoes local charge delocalization, changes the charge distribution of the active center Cu in the copper-based metal organic framework material, and improves the Cu content in the material. + / Cu 2+ The ratio of 2-H-2O-1 is 0.1:1, thereby enhancing the strength and quantity of its Lewis acid sites, which is beneficial to the activation of cyclohexanone and the high-selective generation of ε-caprolactone in the catalytic reaction. Compared with the prior art, the modified copper-based metal organic framework material prepared by the present invention has excellent catalytic activity and cyclic stability as a catalyst, significantly improves the utilization efficiency of the sacrificial agent benzaldehyde in the catalytic reaction, and the catalyst preparation method is simple, which has application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 a is the electron microscope image of Br-HKUST-1 obtained in Example 1, Figure 1 b is the element distribution diagram of Br-HKUST-1 obtained in Example 1, Figure 1 c is the Br element distribution diagram of Br-HKUST-1 obtained in Example 1, Figure 1 d is the Cu element distribution diagram of Br-HKUST-1 obtained in Example 1, Figure 1 e is the O element distribution diagram of Br-HKUST-1 obtained in Example 1, Figure 1 f is the C element distribution diagram of Br-HKUST-1 obtained in Example 1; Figure 2 (a) is the XPS full spectrum of Br-HKUST-1 obtained in Example 1 and HKUST-1 obtained in Comparative Example 1, Figure 2 (b) is the C1s spectra of Br-HKUST-1 of Example 1 and HKUST-1 of Comparative Example 1, Figure 2 (c) is the O1s spectra of Br-HKUST-1 of Example 1 and HKUST-1 of Comparative Example 1, Figure 2 (d) is the Cu 2p spectra of Br-HKUST-1 of Example 1 and HKUST-1 of Comparative Example 1. DETAILED DESCRIPTION

[0017] The present invention provides a method for preparing a modified copper-based metal organic framework material, comprising the following steps: Mixing copper metal salt, mesitylene-3-benzoic acid and a first solvent to perform a crystallization reaction to obtain a copper-based metal organic framework material; Calcination activation of the copper-based metal organic framework material to obtain an activated copper-based metal organic framework material; The activated copper-based metal organic framework material, the modifier and the second solvent are mixed to carry out a modification reaction to obtain a modified copper-based metal organic framework material; The modifier includes tetrabutylammonium chloride, ammonium chloride, tetrabutylammonium bromide, ammonium bromide, tetrabutylammonium iodide or ammonium iodide, and the mass ratio of the copper-based metal organic framework material to the modifier is 1:0.6~1; the temperature of the modification reaction is 25~60°C, and the time is 20~28 h.

[0018] The present invention preferably weighs copper metal salt and trimesic acid, adds them to the first solvent respectively, stirs until completely dissolved, obtains copper salt solution and trimesic acid solution, mixes the two solutions, transfers to a hydrothermal kettle, performs crystallization reaction, and obtains a copper-based metal organic framework material.

[0019] In the present invention, the copper metal salt preferably includes one or more of copper nitrate trihydrate, copper sulfate, copper acetate and copper chloride, and further preferably includes copper sulfate; the molar ratio of the copper metal salt to trimesic acid is preferably 1:1~3:1, and further preferably 2:1~3:1.

[0020] In the present invention, the first solvent preferably includes one or more of N,N-dimethylformamide, methanol, ethanol and water, and further preferably includes N,N-dimethylformamide or methanol. The present invention does not impose any special limitation on the volume of the first solvent, which can be adjusted as required.

[0021] In the present invention, the temperature of the crystallization reaction is preferably 80-120° C., more preferably 90-100° C., and the time is preferably 12-24 h, more preferably 16-20 h.

[0022] After the crystallization reaction is completed, the present invention preferably waits for it to cool to room temperature, centrifuges the obtained solid product, washes it alternately with water and ethanol, and then dries it to obtain a copper-based metal organic framework material (denoted as HKUST-1); the present invention does not specifically limit the number of alternate washings, and in the embodiment of the present invention, it is preferably 3 times.

[0023] In the present invention, the drying temperature is preferably 80 to 100°C, more preferably 85 to 90°C.

[0024] The present invention preferably places the copper-based metal organic framework material in an open crucible bowl and performs calcination activation in a muffle furnace to obtain the activated metal organic framework material.

[0025] In the present invention, the calcination activation temperature is preferably 150-200°C, more preferably 175-180°C, and the time is preferably 8-16 h, more preferably 12-16 h; the calcination activation of the copper-based metal organic framework material is to remove the residual solvent molecules and unreacted organic ligands in the pores.

[0026] In the present invention, the activated copper-based metal organic framework material is preferably cooled to room temperature, quickly transferred to a 100 mL flat-bottom flask, added to the second solvent together with the modifier, stirred, and subjected to modification reaction after uniform mixing to obtain a modified copper-based metal organic framework material; The modifier includes tetrabutylammonium chloride, ammonium chloride, tetrabutylammonium bromide, ammonium bromide, tetrabutylammonium iodide or ammonium iodide, and the mass ratio of the copper-based metal organic framework material to the modifier is 1:0.6~1; the temperature of the modification reaction is 25~60°C, and the time is 20~28 h.

[0027] In the present invention, the modifier preferably includes tetrabutylammonium chloride, ammonium chloride, tetrabutylammonium bromide, ammonium bromide, tetrabutylammonium iodide or ammonium iodide, and further preferably includes tetrabutylammonium bromide; the mass ratio of the copper-based metal organic framework material to the modifier is 1:0.6~1, and further preferably 1:0.8~1.

[0028] In the present invention, the second solvent preferably includes methanol, ethanol or water, and more preferably includes methanol. The present invention does not impose any special restrictions on the volume of the second solvent, as long as the modification reaction proceeds smoothly.

[0029] In the present invention, the stirring temperature is preferably 25-100° C., more preferably 25-60° C., and the stirring time is preferably 24 h.

[0030] In the present invention, the temperature of the modification reaction is preferably 25-60° C., more preferably 30-50° C., and the time is preferably 20-28 h, more preferably 24 h.

[0031] After the modification reaction is completed, the present invention preferably reduces the pressure and filters the product obtained by the modification reaction, and the separated solid product is washed alternately with water and ethanol, and then vacuum dried to obtain a modified copper-based metal organic framework material; the present invention has no special limitation on the number of alternate washings, and in the embodiment of the present invention, 3 times is preferred.

[0032] In the present invention, the vacuum drying temperature is preferably 70-90° C., more preferably 80-90° C., and the time is preferably 20-28 h, more preferably 24 h.

[0033] The invention provides a modified copper-based metal organic framework material prepared by the above preparation method.

[0034] The present invention provides an application of the modified copper-based metal organic framework material in catalyzing the oxidative rearrangement of cyclohexanone to prepare ε-caprolactone. The application method comprises the following steps: mixing benzaldehyde, cyclohexanone, the modified copper-based metal organic framework material and an organic solvent, introducing oxygen or air, and performing an oxidation reaction to obtain ε-caprolactone.

[0035] In the present invention, the molar ratio of benzaldehyde to cyclohexanone is preferably 0.5-2.5:1, more preferably 2:1.

[0036] In the present invention, the organic solvent preferably includes 1,2-dichloroethane, 1,4-dioxane, acetonitrile or ethyl acetate, and further preferably includes 1,2-dichloroethane.

[0037] In the present invention, the pressure of the oxygen or air is preferably 0.2-0.6 MPa, more preferably 0.2-0.4 MPa.

[0038] In the present invention, the temperature of the oxidation reaction is preferably 40-70° C., more preferably 55-65° C., and the time is preferably 4-9 h, more preferably 5-7 h.

[0039] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention. Example 1

[0040] Weigh 2.51 g of copper sulfate and add it to 48 mL of methanol, stir and dissolve at room temperature to obtain a copper sulfate solution; weigh 1.72 g of trimesic acid and add it to 48 mL of N,N-dimethylformamide, stir and dissolve at room temperature to obtain a trimesic acid solution; The copper sulfate solution and the trimesic acid solution were mixed and transferred to a hydrothermal reactor, which was placed in a 90°C oven for 16 h to perform a crystallization reaction. After the reaction was completed, the solid product was cooled to room temperature, centrifuged, washed alternately with water and anhydrous ethanol for three times, and then placed in an 85°C oven to dry for use, thereby obtaining a modified copper-based metal organic framework material (denoted as HKUST-1 material); 0.5 g of HKUST-1 material was weighed and placed in an open crucible bowl, and calcined and activated in a muffle furnace at 150 °C for 12 h; After drying, it was cooled to room temperature, and the activated HKUST-1 material was quickly transferred to a 100 mL flat-bottom flask, mixed with 30 mL methanol and 0.30 g tetrabutylammonium bromide, and stirred at 25 °C for 24 h to carry out the modification reaction. After the reaction, the obtained product was filtered under reduced pressure, washed alternately with anhydrous ethanol and water for 3 times, and dried in a vacuum at 70 °C for 24 h. The weight was weighed for later use to obtain a modified copper-based metal-organic framework material (denoted as Br-HKUST-1). Example 2

[0041] Weigh 3.14 g of copper acetate and add it to 48 mL of N,N-dimethylformamide, stir and dissolve at room temperature to obtain a copper acetate solution; weigh 1.72 g of trimesic acid and add it to 48 mL of ethanol, stir and dissolve at room temperature to obtain a trimesic acid solution; The copper acetate solution and the trimesic acid solution were mixed and transferred to a hydrothermal kettle, which was placed in a 100°C oven for 20 h for crystallization reaction. After the reaction was completed, the product was cooled to room temperature, and the solid product was centrifuged, washed alternately with water and anhydrous ethanol for 3 times, and then placed in a 90°C oven for drying to obtain HKUST-1 material. 0.5 g of HKUST-1 material was weighed and placed in an open crucible bowl, and calcined and activated in a muffle furnace at 175 °C for 12 h; After drying, it was cooled to room temperature, and the activated HKUST-1 material was quickly transferred to a 100 mL flat-bottom flask, mixed with 30 mL ethanol and 0.40 g ammonium iodide, and stirred at 60 °C for 24 h to carry out the modification reaction. After the reaction, the obtained product was filtered under reduced pressure, washed alternately with anhydrous ethanol and water for 3 times, and dried in a vacuum at 80 °C for 24 h. The weight was weighed for later use to obtain a modified copper-based metal-organic framework material (denoted as I-HKUST-1). Example 3

[0042] Weigh 2.11 g of copper chloride and add it to 48 mL of water, stir and dissolve at room temperature to obtain a copper chloride solution; weigh 1.72 g of trimesic acid and add it to 48 mL of methanol, stir and dissolve at room temperature to obtain a trimesic acid solution; The copper chloride solution and the trimesic acid solution were mixed and transferred to a hydrothermal kettle, which was placed in a 120°C oven for 24 h to perform a crystallization reaction. After the reaction was completed, the product was cooled to room temperature, and the solid product was centrifuged, washed alternately with water and anhydrous ethanol for three times, and then placed in a 100°C oven to dry for use, thereby obtaining the HKUST-1 material. 0.5 g of HKUST-1 material was weighed, placed in an open crucible bowl, and calcined and activated in a muffle furnace at 200 °C for 12 h; After drying, it was cooled to room temperature, and the activated HKUST-1 material was quickly transferred to a 100 mL flat-bottom flask, mixed with 30 mL of water and 0.40 g of ammonium chloride, and stirred at 40 °C for 24 h to carry out the modification reaction. After the reaction, the obtained product was filtered under reduced pressure, washed alternately with ethanol and water for 3 times, and dried in a vacuum at 90 °C for 24 h. The weight was weighed for later use to obtain a modified copper-based metal-organic framework material (denoted as Cl-HKUST-1). Example 4

[0043] Weigh 3.8 g of copper nitrate trihydrate and add it to 48 mL of water, stir and dissolve at room temperature to obtain a copper nitrate solution; weigh 1.72 g of trimesic acid and add it to 48 mL of anhydrous ethanol, stir and dissolve at room temperature to obtain a trimesic acid solution; The copper nitrate solution and the trimesic acid solution were mixed and transferred to a hydrothermal kettle, which was placed in an oven at 80°C for 12 h for crystallization reaction. After the reaction was completed, the mixture was cooled to room temperature, and the obtained solid product was centrifuged, washed alternately with water and anhydrous ethanol for 3 times, and then dried in an oven at 80°C to obtain the HKUST-1 material. 0.5 g of HKUST-1 material was weighed, placed in an open crucible bowl, and calcined and activated in a muffle furnace at 180 °C for 12 h; After drying, it was cooled to room temperature, and the activated HKUST-1 material was quickly transferred to a 100 mL flat-bottom flask, mixed with 30 mL methanol and 0.40 g ammonium bromide, and stirred at 25 °C for 24 h for modification reaction. After the reaction, the solid was separated, washed alternately with anhydrous ethanol and water for 3 times, and vacuum dried at 70 °C for 24 h to obtain a modified copper-based metal-organic framework material, recorded as Br-HKUST-1 (0.8:1), where 0.8:1 is the mass ratio of HKUST-1 material to ammonium bromide. Example 5

[0044] The only difference from Example 4 is that: The amount of ammonium bromide added was changed from 0.40 g to 0.25 g; Br-HKUST-1 (0.5:1) was obtained.

[0045] Comparative Example 1 Weigh 3.8 g of copper nitrate trihydrate and add it to 48 mL of water, stir and dissolve at room temperature to obtain a copper nitrate solution; weigh 1.72 g of trimesic acid and add it to 48 mL of anhydrous ethanol, stir and dissolve at room temperature to obtain a trimesic acid solution; The copper nitrate solution and the trimesic acid solution were mixed and transferred to a hydrothermal kettle, and the hydrothermal kettle was placed in an oven at 80°C for 12 h to perform a crystallization reaction; After the crystallization reaction is completed, the solid product is cooled to room temperature, centrifuged, washed alternately with water and anhydrous ethanol three times, and then placed in an oven at 80°C for use to obtain a copper-based metal organic framework material (HKUST-1).

[0046] Characterization and performance testing 1. Observe the Br-HKUST-1 obtained in Example 1 using a transmission electron microscope. Figure 1 .

[0047] like Figure 1 As shown in a, it can be observed that Br-HKUST-1 has a regular octahedral morphology structure; Figure 1 b is the element distribution diagram of Br-HKUST-1 obtained in Example 1, Figure 1 Middle c, Figure 1 Middle d, Figure 1 Zhongehe Figure 1 f in the figure are the Br element distribution diagram, Cu element distribution diagram, O element distribution diagram and C element distribution diagram of Br-HKUST-1 obtained in Example 1, respectively. It can be clearly observed that the uniform distribution of Br, Cu, O and C elements is observed.

[0048] 2. Using X-ray photoelectron scanning, the Br-HKUST-1 obtained in Example 1 and the HKUST-1 obtained in Comparative Example 1 were obtained. Figure 2 In (a), after carbon charge correction and peak fitting, we get Figure 2 Middle (b), Figure 2 (c) and Figure 2 Middle (d).

[0049] like Figure 2 As shown in (a), Br-HKUST-1 and HKUST-1 both contain C, O, and Cu elements; Figure 2 As shown in (b), compared with HKUST-1, the center of the C1s characteristic peak of Br-HKUST-1 shifts toward the low binding energy direction. The hydrogen atom of the meta-carbon-hydrogen bond of the benzene ring in the ligand (trimesic acid) is replaced by halogen (Br), which causes the ligand to undergo local charge delocalization. Figure 2 As shown in (c), the MO (metal-oxygen bond) peak area ratio of Br-HKUST-1 decreased, indicating that the ligand underwent local charge delocalization, which weakened the strength of the metal-oxygen bond. Figure 2 As shown in (d), the hydrogen atom of the carbon-hydrogen bond at the meta position of the benzene ring in the ligand (trimesic acid) is replaced by a halogen (Br), which causes the ligand to undergo local charge delocalization, weakens the strength of the metal-oxygen bond, changes the charge distribution of the active center Cu in the copper-based metal-organic framework material, and increases the Cu content in the material. + / Cu 2+ proportion.

[0050] 3. Test Example 1: In a micro-autoclave, 25 mg of the catalysts obtained in Examples 1 to 3 and Comparative Example 1, 2 mmol of cyclohexanone, 2 mmol (1.0 equivalent) of benzaldehyde, and 5 mL of 1,2-dichloroethane were added, respectively, and the mixture was heated at 50°C, 6 h, and 0.3 MPa O 2 The Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone was carried out under the conditions of , after the reaction was completed, the reaction mixture was cooled to room temperature, the reaction product was centrifuged to separate the catalyst, and the reaction liquid was collected.

[0051] Gas chromatography was used to quantitatively analyze the content of each component in the product, and the cyclohexanone conversion rate, ε-caprolactone selectivity, benzaldehyde conversion rate and aldehyde utilization rate of the reactions under different catalysts were calculated, wherein the aldehyde utilization rate was calculated by dividing the molar amount of ε-caprolactone generated by the molar amount of benzaldehyde consumed. The results are shown in Table 1.

[0052]

[0053] Combining Table 1 with Examples 1 to 3 and Comparative Example 1, it can be seen that the copper-based metal organic framework material modified by halogen (Cl, Br, I) significantly improves the selectivity of ε-caprolactone and the utilization rate of benzaldehyde compared to before modification, among which Br modification has the best effect.

[0054] 4. Test Example 2: In a micro-autoclave, 25 mg of the catalyst obtained in Examples 1 to 3, 2 mmol of cyclohexanone, 2 mmol (1.0 equivalent) of benzaldehyde and 5 mL of 1,2-dichloroethane were added respectively, and the Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone was carried out under different oxidation reaction conditions. After the reaction was completed, the reaction was cooled to room temperature, the reaction product was centrifuged, the catalyst was separated, and the reaction liquid was collected.

[0055] Gas chromatography was used to quantitatively analyze the content of each component in the product, and the cyclohexanone conversion rate, ε-caprolactone selectivity, benzaldehyde conversion rate and aldehyde utilization rate under different oxidation reaction conditions were calculated. The results are shown in Table 2.

[0056]

[0057] As shown in Table 2, the halogen (Cl, Br, I) modified copper-based metal organic framework materials have good reaction performance and benzaldehyde utilization rate in the Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone. The increase of temperature, time and reaction pressure is conducive to the improvement of cyclohexanone conversion rate.

[0058] 5. Test Example 3: In a micro autoclave, 25 mg of the Br-HKUST-1 (0.8:1) catalyst obtained in Example 4 and the Br-HKUST-1 (0.5:1) catalyst obtained in Example 5, 2 mmol of cyclohexanone, 2 mmol (1.0 equivalent) of benzaldehyde, and 5 mL of 1,2-dichloroethane were added, respectively, and the mixture was heated at 50 °C, 6 h, and 0.3 MPa O 2 The Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone was carried out under the conditions of , after the reaction was completed, the reaction mixture was cooled to room temperature, the reaction product was centrifuged to separate the catalyst, and the reaction liquid was collected.

[0059] Gas chromatography was used to quantitatively analyze the content of each component in the product, and the cyclohexanone conversion rate, ε-caprolactone selectivity, benzaldehyde conversion rate and aldehyde utilization rate of the reaction under different bromine-modified copper-based metal organic framework materials as catalysts were calculated. The results are shown in Table 3.

[0060]

[0061] As shown in Table 3, the reaction efficiency and product selectivity of the oxidation reaction under the action of Br-HKUST-1 (0.8:1) catalyst are better than those of Br-HKUST-1 (0.5:1) catalyst, the cyclohexanone conversion rate is 72.9%, the ε-caprolactone selectivity is 94.8%, the benzaldehyde conversion rate is 90.1%, and the aldehyde utilization rate is 0.77.

[0062] 6. Test Example 4: In a micro-autoclave, 25 mg of the Br-HKUST-1 (0.8:1) catalyst obtained in Example 4, 2 mmol of cyclohexanone, different molar amounts of benzaldehyde, and 5 mL of 1,2-dichloroethane were added and heated at 55 °C, 6 h, 0.3 MPa O 2 The Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone was carried out under oxidation reaction conditions. After the reaction was completed, the reaction mixture was cooled to room temperature, the reaction product was centrifuged to separate the catalyst and the reaction liquid was collected.

[0063] Gas chromatography was used to quantitatively analyze the content of each component in the product, and the cyclohexanone conversion rate, ε-caprolactone selectivity, benzaldehyde conversion rate and aldehyde utilization rate under the conditions of different molar amounts of benzaldehyde were calculated. The results are shown in Table 4.

[0064]

[0065] It can be seen from Table 4 that when the bromine-modified copper-based metal organic framework material is used as a catalyst, the reaction has a high aldehyde utilization rate (0.6~1) at a low aldehyde-ketone stoichiometric ratio (0.5~1.5); when the aldehyde-ketone stoichiometric ratio is greater than or equal to 2, cyclohexanone can be completely converted and the yield of ε-caprolactone is more than 90%.

[0066] 7. Test Example 5: In a micro-autoclave, 25 mg of the Br-HKUST-1 (0.8:1) catalyst obtained in Example 4, 2 mmol of cyclohexanone, 2 mmol (1.0 equivalent) of benzaldehyde, and 5 mL of 1,2-dichloroethane were added and heated at 50 °C for 6 h under 0.3 MPaO 2 The Baeyer-Villiger oxidation rearrangement reaction of cyclohexanone was carried out cyclically under the conditions of , and the catalyst cycle stability test was carried out. After the reaction was completed, it was cooled to room temperature, the reaction product was centrifuged, the catalyst was separated, and the reaction liquid was collected.

[0067] Gas chromatography was used to quantitatively analyze the content of each component in the product, and the cyclohexanone conversion rate, ε-caprolactone selectivity, benzaldehyde conversion rate and aldehyde utilization rate of the reaction under different cycle numbers were calculated. The results are shown in Table 5.

[0068]

[0069] As shown in Table 5, the modified copper-based metal organic framework material in the present invention has good cyclic stability when used to catalyze the Baeyer-Villiger oxidation rearrangement of cyclohexanone to prepare ε-caprolactone.

[0070] It can be seen from the above embodiments and test examples that the present invention provides a modified copper-based metal-organic framework material, which significantly improves the selectivity of ε-caprolactone and the utilization rate of benzaldehyde after halogen (Cl, Br, I) modification, wherein the bromine-modified catalyst has the best effect, and the feeding amount of the copper-based metal-organic framework material and the halogen-containing modifier is preferably 0.6~1:1; the modified copper-based metal-organic framework material obtained by the present invention has excellent catalytic activity and cyclic stability as a catalyst, and significantly improves the utilization efficiency of the sacrificial agent benzaldehyde in the catalytic reaction.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing a modified copper-based metal organic framework material, characterized in that: The following steps are involved: Mixing copper metal salt, mesitylene-3-benzoic acid and a first solvent to perform a crystallization reaction to obtain a copper-based metal organic framework material; Calcination activation of the copper-based metal organic framework material to obtain an activated copper-based metal organic framework material; The activated copper-based metal organic framework material, the modifier and the second solvent are mixed to carry out a modification reaction to obtain a modified copper-based metal organic framework material; The modifier includes tetrabutylammonium chloride, ammonium chloride, tetrabutylammonium bromide, ammonium bromide, tetrabutylammonium iodide or ammonium iodide, and the mass ratio of the copper-based metal organic framework material to the modifier is 1:0.6~1; the temperature of the modification reaction is 25~60°C, and the time is 20~28 h.

2. The preparation method according to claim 1, characterized in that: The copper metal salt includes one or more of copper nitrate trihydrate, copper sulfate, copper acetate and copper chloride; the molar ratio of the copper metal salt to trimesic acid is 1:1 to 3:1; The first solvent includes one or more of N,N-dimethylformamide, methanol, ethanol and water.

3. The preparation method according to claim 1, characterized in that: The temperature of the crystallization reaction is 80-120° C. and the time is 12-24 h.

4. The preparation method according to claim 1, characterized in that: The calcination activation temperature is 150-200° C. and the time is 8-16 h.

5. The preparation method according to claim 1, characterized in that: The second solvent includes methanol, ethanol or water.

6. The modified copper-based metal organic framework material prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the modified copper-based metal organic framework material according to claim 6 in catalyzing the oxidative rearrangement of cyclohexanone to prepare ε-caprolactone, characterized in that: The application method comprises the following steps: mixing benzaldehyde, cyclohexanone, the modified copper-based metal organic framework material and an organic solvent, introducing oxygen or air, and performing an oxidation reaction to obtain ε-caprolactone.

8. The use according to claim 7, characterized in that: The molar ratio of benzaldehyde to cyclohexanone is 0.5-2.5:1; the organic solvent includes 1,2-dichloroethane, 1,4-dioxane, acetonitrile or ethyl acetate.

9. The use according to claim 7, characterized in that: The pressure of the oxygen or air is 0.2-0.6 MPa; the temperature of the oxidation reaction is 40-70° C., and the time is 4-9 h.

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