Nitrogen-doped carbon-foam metal composites and methods for making same, processes for co-producing epsilon-caprolactone and propionic acid
By using nitrogen-doped carbon-foam metal composite materials as catalysts, the problems of low activity and easy wear of carbon catalysts in the cyclohexanone oxidation reaction are solved, achieving efficient catalysis and easy separation, which is suitable for industrial application and can co-produce high-value ε-caprolactone and propionic acid.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2024-01-18
- Publication Date
- 2026-07-14
AI Technical Summary
In the existing technology, carbon material catalysts in the Baeyer-Villiger oxidation reaction of cyclohexanone have problems such as low catalytic activity, low mass transfer efficiency, difficulty in separating the catalyst from the reactants, and easy wear and loss, making it difficult to realize industrial application.
A nitrogen-doped carbon-foam metal composite material was used. By attaching a porous alumina layer and growing nitrogen-doped carbon nanotubes in situ on a foam metal matrix, the composite material was used as a catalyst for the oxidation reaction of cyclohexanone and propionaldehyde. Combined with oxygen as an oxidant, the co-production of ε-caprolactone and propionic acid was achieved.
This composite material exhibits high catalytic activity and good stability. It is easily separated from reactants and is not prone to wear or loss, making it suitable for large-scale industrial applications. Furthermore, the conversion of propionaldehyde into high-value propionic acid enhances economic feasibility.
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Figure CN118022850B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of catalysis technology, specifically to nitrogen-doped carbon-foam metal composite materials and their preparation methods, as well as methods for co-producing ε-caprolactone and propionic acid. Background Technology
[0002] ε-Caprolactone is a novel polyester monomer that can be copolymerized with other monomers to improve material properties. Poly(ε-caprolactone) (PCL) possesses good thermoplasticity, biocompatibility, and biodegradability, making it widely applicable in biomedical and environmentally friendly materials. Currently, ε-caprolactone is mainly prepared by Baeyer-Villiger oxidation of cyclohexanone as a raw material. The oxidants used in this reaction include peroxyacids, H₂O₂, monooxygenases, and O₂. O₂, as an oxidant, offers advantages such as cleanliness, safety, and low cost, and aligns with the requirements of green chemistry. Therefore, the method of preparing ε-caprolactone by Baeyer-Villiger oxidation of cyclohexanone using O₂ as an oxidant shows the greatest potential for development.
[0003] Liu et al. prepared ε-caprolactone by reacting cyclohexanone as a raw material, oxygen as an oxidant, benzaldehyde as a co-oxidant, and ordered mesoporous Sn-TiO2 as a catalyst at 70℃ for 5 h. The conversion rate of cyclohexanone was as high as 94.1%, and the selectivity of ε-caprolactone was as high as 95.2% (Chemistryselect,2018,3(23):6434-6439). Li et al. prepared ε-caprolactone by reacting cyclohexanone as a raw material, oxygen as an oxidant, benzaldehyde as a co-oxidant, and Fe(tpfc)Cl as a catalyst. The conversion rate of cyclohexanone was as high as 90.7%, and the selectivity of ε-caprolactone was 72.6% (European Journal of Organic Chemistry,2022,2022(25)). However, although the two methods mentioned above have high conversion rates of cyclohexanone and high selectivity for ε-caprolactone, the weak oxidizing power of O2 necessitates the use of benzaldehyde as a co-oxidant, which leads to difficulties in product separation. Furthermore, the ordered mesoporous Sn-TiO2 catalyst used in the first method is in powder form, which easily clogs the reaction apparatus and is not conducive to industrial application.
[0004] In recent years, carbon-based catalysts have attracted widespread attention due to their low cost, environmental friendliness, porous structure, and tunable surface chemistry. The first application of carbon-based catalysts in the Baeyer-Villiger oxidation of cyclohexanone began in 2012. Nabae et al. used several carbon materials (e.g., Ketjen black, XC-72 carbon, etc.) in the same oxidation system for the Baeyer-Villiger oxidation of cyclohexanone, with Ketjen black exhibiting the highest catalytic activity. At 50°C for 6 hours, the yield of ε-caprolactone reached 91% (ACS catalysis, 2013, 3(2):230-236). However, carbon materials are generally used as catalysts in powder form, which not only results in low mass transfer efficiency but also makes catalyst separation from reactants difficult, leading to significant catalyst wear and loss, which is detrimental to industrial production.
[0005] Therefore, it is of great significance to develop a catalyst with good catalytic activity, high catalytic efficiency, good stability, easy separation from reactants, and resistance to wear and loss. Summary of the Invention
[0006] The purpose of this invention is to provide nitrogen-doped carbon-foam metal composite materials and their preparation methods, as well as methods for co-producing ε-caprolactone and propionic acid.
[0007] The technical solution adopted in this invention is:
[0008] A nitrogen-doped carbon-foam metal composite material, comprising a foam metal matrix, a porous alumina layer attached to the surface of the foam metal matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam metal matrix.
[0009] Preferably, the foam metal in the foam metal matrix is one of foam Ni, foam Fe, foam Co, foam Fe-Cr alloy, foam Ni-Fe alloy, and foam Ni-Co alloy.
[0010] Preferably, the porosity of the foamed metal matrix is 20 ppi to 100 ppi.
[0011] More preferably, the porosity of the foamed metal matrix is 20 ppi to 40 ppi.
[0012] Preferably, the alumina loading on the surface of the foamed metal matrix is 3.0 wt% to 31.4 wt%.
[0013] More preferably, the alumina loading on the surface of the foamed metal matrix is 5.0 wt% to 8.0 wt%.
[0014] Preferably, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 4.5% to 27.0%.
[0015] More preferably, the nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material have a mass percentage content of 5.0% to 8.0%.
[0016] Preferably, the nitrogen content of the nitrogen-doped carbon nanotubes is 0.23 at% to 3.5 at%.
[0017] More preferably, the nitrogen-doped carbon nanotubes have a nitrogen content of 3.0 at% to 3.5 at%.
[0018] A method for preparing the nitrogen-doped carbon-foam metal composite material as described above includes the following steps:
[0019] 1) An alumina sol is attached to the surface of the foam metal by impregnation, and then impregnated in formamide for a solvothermal reaction to obtain a foam metal with a porous alumina layer;
[0020] 2) The foam metal containing the porous alumina layer is calcined in a protective atmosphere to obtain the nitrogen-doped carbon-foam metal composite material.
[0021] Preferably, the foam metal in step 1) has been cleaned and dried before use. Specifically, the foam metal is ultrasonically cleaned with acetone and ethanol for 20 min to 40 min each, then cleaned with water, and then dried at a temperature of 90℃ to 110℃ for 20 h to 30 h.
[0022] Preferably, the solvothermal reaction in step 1) is carried out at a temperature of 170℃ to 190℃ for a reaction time of 10h to 15h.
[0023] Preferably, the protective atmosphere in step 2) is a nitrogen atmosphere or an argon atmosphere.
[0024] Preferably, the calcination in step 2) is carried out at a temperature of 700℃~900℃ for 1h~3h.
[0025] A method for the co-production of ε-caprolactone and propionic acid includes the following steps:
[0026] The nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Cyclohexanone, propionaldehyde and organic solvent were then added to the reactor, and oxygen was introduced to carry out the reaction, thus obtaining a reaction solution containing ε-caprolactone and propionic acid.
[0027] Preferably, the mass ratio of cyclohexanone to nitrogen-doped carbon-foam metal composite material is 1:0.001 to 0.05.
[0028] More preferably, the mass ratio of cyclohexanone to nitrogen-doped carbon-foam metal composite material is 1:0.01 to 0.04.
[0029] Preferably, the molar ratio of cyclohexanone to propionaldehyde is 1:0.1 to 10.
[0030] More preferably, the molar ratio of cyclohexanone to propionaldehyde is 1:0.1 to 2.
[0031] Preferably, the organic solvent is at least one selected from 1,2-dichloroethane, acetonitrile, and ethyl acetate.
[0032] Preferably, the pressure inside the reactor after oxygen is introduced is 0.2 MPa to 2 MPa.
[0033] More preferably, the pressure inside the reactor after oxygen is introduced is 0.5 MPa to 1.5 MPa.
[0034] Preferably, the reaction is carried out at a temperature of 30°C to 70°C for a time of 2 hours to 10 hours.
[0035] More preferably, the reaction is carried out at a temperature of 40°C to 60°C for a time of 3 to 8 hours.
[0036] Preferably, the reaction is carried out at a stirring speed of 200 r / min to 600 r / min.
[0037] More preferably, the reaction is carried out at a stirring speed of 300 r / min to 600 r / min.
[0038] The beneficial effects of the present invention are: the nitrogen-doped carbon-foam metal composite material of the present invention has the advantages of good catalytic activity, high catalytic efficiency, good stability, easy separation from reactants, and resistance to wear and loss in the oxidation reaction of cyclohexanone and propionaldehyde. Moreover, its preparation method is simple and suitable for large-scale industrial application.
[0039] Specifically:
[0040] 1) The nitrogen-doped carbon-foam metal composite material of the present invention can be used as both a catalyst and a stirring device, overcoming the problems of easy wear and loss and difficulty in separating solid-liquid mixed products that are common in traditional powdered catalysts.
[0041] 2) The nitrogen-doped carbon-foam metal composite material of the present invention is easy to install and disassemble in the reactor, which can save time;
[0042] 3) This invention uses propionaldehyde as a co-oxidant, which will be converted into propionic acid with higher economic value, making the reaction more industrially valuable and improving economic feasibility.
[0043] 4) The nitrogen-doped carbon-foam metal composite material of the present invention has good catalytic activity, high catalytic efficiency and good stability for the oxidation reaction of cyclohexanone and propionaldehyde. Attached Figure Description
[0044] Figure 1 This is a schematic diagram of the reactor in Example 1.
[0045] Figure 2 This is a physical image of the nitrogen-doped carbon-foam metal composite material in Example 1.
[0046] Figure 3 This is a gas chromatogram of the reaction solution containing ε-caprolactone and propionic acid in Example 1. Detailed Implementation
[0047] The present invention will be further explained and described below with reference to specific embodiments.
[0048] Example 1:
[0049] A nitrogen-doped carbon-foam metal composite material is composed of a foam Ni matrix (cylindrical, 45 mm in diameter, 30 mm in height, and 40 ppi porosity), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at.
[0050] The preparation method of the above nitrogen-doped carbon-foam metal composite material is as follows:
[0051] 1) The foamed Ni was ultrasonically cleaned with acetone and ethanol for 30 min each, then cleaned with deionized water, and dried at 100℃ for 24 h. Then, the foamed Ni was coated with alumina sol by immersion (immersing the foamed Ni in alumina sol and then taking it out). The foamed Ni was then immersed in formamide at 180℃ for 12 h. After natural cooling to room temperature, it was dried to obtain foamed metal with a porous alumina layer.
[0052] 2) Place the foam metal containing the porous alumina layer in a tube furnace, fill it with nitrogen, heat it to 800℃ and keep it at that temperature for 2 hours, and then let it cool naturally to room temperature to obtain the nitrogen-doped carbon-foam metal composite material.
[0053] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0054] 0.0442 g of the above nitrogen-doped carbon-foam metal composite material was installed in the reactor (see schematic diagram of the reactor). Figure 1As shown in the image, a physical diagram of the nitrogen-doped carbon-foam metal composite material is as follows: Figure 2 On the stirring shaft (as shown), 1.1045 g of cyclohexanone, 3.1581 g of propionaldehyde, and 55.5711 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 60°C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 1.5 MPa. The reaction was then carried out for 5 hours and allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0055] Performance testing:
[0056] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The obtained gas chromatogram is shown below. Figure 3 As shown.
[0057] Depend on Figure 3 It can be seen that the conversion rate of cyclohexanone is 93.27%, the selectivity of ε-caprolactone is 100%, the conversion rate of propionaldehyde is 69.02%, and the selectivity of propionic acid is 98.15%.
[0058] Example 2:
[0059] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylinder, diameter 45 mm, height 30 mm, porosity 20 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0060] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0061] 0.0102 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.0243 g of cyclohexanone, 3.2163 g of propionaldehyde and 55.5632 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 35 °C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 1 MPa. The reaction was then carried out for 5 hours and allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0062] Performance testing:
[0063] The reaction solution containing ε-caprolactone and propionic acid in this example was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 77.22%, the selectivity of ε-caprolactone was 99.13%, the conversion rate of propionaldehyde was 46.15%, and the selectivity of propionic acid was 88.40%.
[0064] Example 3:
[0065] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylindrical, with a diameter of 45 mm, a height of 10 mm, and a porosity of 20 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0066] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0067] 0.0123 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.2279 g of cyclohexanone, 2.7133 g of propionaldehyde and 55.5819 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 60 °C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 0.5 MPa. The reaction was carried out for 5 hours and then naturally cooled to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0068] Performance testing:
[0069] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 81.95%, the selectivity of ε-caprolactone was 100%, the conversion rate of propionaldehyde was 55.30%, and the selectivity of propionic acid was 89.39%.
[0070] Example 4:
[0071] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Co matrix (cylindrical, with a diameter of 45 mm, a height of 30 mm, and a porosity of 40 ppi), a porous alumina layer attached to the surface of the foam Co matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Co matrix. The alumina loading on the surface of the foam Co matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.17 at.
[0072] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0073] 0.0242 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 2.4196 g of cyclohexanone, 0.7247 g of propionaldehyde and 55.7183 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 60 °C, the stirring speed was controlled at 300 rpm, and oxygen was introduced until the pressure inside the reactor reached 1.2 MPa. The reaction was carried out for 5 hours and then naturally cooled to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0074] Performance testing:
[0075] The reaction solution containing ε-caprolactone and propionic acid in this example was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 41.36%, the selectivity of ε-caprolactone was 98.10%, the conversion rate of propionaldehyde was 51.36%, and the selectivity of propionic acid was 91.47%.
[0076] Example 5:
[0077] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylindrical, with a diameter of 45 mm, a height of 20 mm, and a porosity of 40 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0078] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0079] 0.0488 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.2194 g of cyclohexanone, 4.2769 g of propionaldehyde and 55.7957 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 50 °C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 1 MPa. The reaction was carried out for 2 hours and then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0080] Performance testing:
[0081] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 89.98%, the selectivity of ε-caprolactone was 98.30%, the conversion rate of propionaldehyde was 65.54%, and the selectivity of propionic acid was 86.68%.
[0082] Example 6:
[0083] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni-Co matrix (cylindrical, with a diameter of 45 mm, a height of 30 mm, and a porosity of 40 ppi), a porous alumina layer attached to the surface of the foam Ni-Co matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni-Co matrix. The alumina loading on the surface of the foam Ni-Co matrix is 6.7 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.6%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.3 at%.
[0084] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0085] 0.0503 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 2.5155 g of cyclohexanone, 1.4292 g of propionaldehyde and 56.1098 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 60 °C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 1 MPa. The reaction was then carried out for 5 hours and allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0086] Performance testing:
[0087] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 54.29%, the selectivity of ε-caprolactone was 98.16%, the conversion rate of propionaldehyde was 60.23%, and the selectivity of propionic acid was 86.72%.
[0088] Example 7:
[0089] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylinder, diameter 45 mm, height 30 mm, porosity 40 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0090] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0091] 0.0246 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 2.4571 g of cyclohexanone, 7.8949 g of propionaldehyde and 55.5762 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 50 °C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 1.2 MPa. The reaction was carried out for 5 hours and then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0092] Performance testing:
[0093] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 85.44%, the selectivity of ε-caprolactone was 97.89%, the conversion rate of propionaldehyde was 50.07%, and the selectivity of propionic acid was 89.55%.
[0094] Example 8:
[0095] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylinder, diameter 45 mm, height 30 mm, porosity 40 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 5.8%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0096] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0097] 0.0122 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.2258 g of cyclohexanone, 3.5212 g of propionaldehyde and 55.7018 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 55 °C, and the stirring speed was controlled at 400 rpm. Oxygen was then introduced until the pressure inside the reactor reached 1 MPa, and the reaction was carried out for 5 hours. The mixture was then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0098] Performance testing:
[0099] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 92.11%, the selectivity of ε-caprolactone was 98.89%, the conversion rate of propionaldehyde was 51.53%, and the selectivity of propionic acid was 89.34%.
[0100] Example 9:
[0101] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylinder, diameter 45 mm, height 30 mm, porosity 20 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0102] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0103] 0.0122 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.2217 g of cyclohexanone, 4.2111 g of propionaldehyde and 55.8153 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 30 °C, the stirring speed was controlled at 600 rpm, and oxygen was introduced until the pressure inside the reactor reached 0.6 MPa. The reaction was carried out for 8 hours and then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0104] Performance testing:
[0105] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 89.94%, the selectivity of ε-caprolactone was 100%, the conversion rate of propionaldehyde was 42.93%, and the selectivity of propionic acid was 78.29%.
[0106] Example 10:
[0107] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Ni matrix (cylindrical, with a diameter of 45 mm, a height of 20 mm, and a porosity of 40 ppi), a porous alumina layer attached to the surface of the foam Ni matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Ni matrix. The alumina loading on the surface of the foam Ni matrix is 6.9 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.7%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.5 at%.
[0108] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0109] 0.0245 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.2264 g of cyclohexanone, 4.9122 g of propionaldehyde and 56.0182 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 50 °C, and the stirring speed was controlled at 600 rpm. Oxygen was then introduced until the pressure inside the reactor reached 1.5 MPa, and the reaction was carried out for 5 hours. The mixture was then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0110] Performance testing:
[0111] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 92.31%, the selectivity of ε-caprolactone was 99.28%, the conversion rate of propionaldehyde was 49.91%, and the selectivity of propionic acid was 89.93%.
[0112] Example 11:
[0113] A nitrogen-doped carbon-foam metal composite material (prepared according to the method of Example 1) is composed of a foam Fe matrix (cylinder, diameter 45 mm, height 30 mm, porosity 40 ppi), a porous alumina layer attached to the surface of the foam Fe matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foam Fe matrix. The alumina loading on the surface of the foam Fe matrix is 5.8 wt%, the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 6.1%, and the nitrogen content of the nitrogen-doped carbon nanotubes is 3.1 at%.
[0114] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0115] 0.0123 g of the above nitrogen-doped carbon-foam metal composite material was installed on the stirring shaft of the reactor. Then, 1.2268 g of cyclohexanone, 0.7221 g of propionaldehyde and 56.0192 g of 1,2-dichloroethane were added to the reactor. The mixture was then heated to 50 °C, and the stirring speed was controlled at 500 rpm. Oxygen was then introduced until the pressure inside the reactor reached 1 MPa, and the reaction was carried out for 5 hours. The mixture was then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0116] Performance testing:
[0117] The reaction solution containing ε-caprolactone and propionic acid in this embodiment was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 45.70%, the selectivity of ε-caprolactone was 100%, the conversion rate of propionaldehyde was 76.83%, and the selectivity of propionic acid was 87.46%.
[0118] Comparative example:
[0119] A method for the co-production of ε-caprolactone and propionic acid, comprising the following steps:
[0120] 1.1107 g of cyclohexanone, 3.1759 g of propionaldehyde and 55.5788 g of 1,2-dichloroethane were added to the reactor, heated to 50 °C, and stirred at 600 rpm. Oxygen was then introduced until the pressure inside the reactor reached 1.5 MPa, and the reaction was carried out for 5 hours. The mixture was then allowed to cool naturally to room temperature to obtain a reaction solution containing ε-caprolactone and propionic acid.
[0121] Performance testing:
[0122] The reaction solution containing ε-caprolactone and propionic acid in this comparative example was analyzed by gas chromatography (GC) (with o-dichlorobenzene as the internal standard). The test results are as follows: the conversion rate of cyclohexanone was 38.45%, the selectivity of ε-caprolactone was 88.54%, the conversion rate of propionaldehyde was 43.70%, and the selectivity of propionic acid was 47.79%.
[0123] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A nitrogen-doped carbon-foam metal composite material, characterized in that, The composition includes a foamed metal matrix, a porous alumina layer attached to the surface of the foamed metal matrix, and nitrogen-doped carbon nanotubes grown in situ on the surface of the foamed metal matrix; the nitrogen-doped carbon-foamed metal composite material is prepared by a method including the following steps: 1) attaching alumina sol to the surface of the foamed metal by impregnation, and then impregnating it in formamide for a solvothermal reaction to obtain a foamed metal containing a porous alumina layer; 2) calcining the foamed metal containing the porous alumina layer in a protective atmosphere to obtain the nitrogen-doped carbon-foamed metal composite material.
2. The nitrogen-doped carbon-foam metal composite material according to claim 1, characterized in that: The foam metal in the foam metal matrix is one of foam Ni, foam Fe, foam Co, foam Fe-Cr alloy, foam Ni-Fe alloy, and foam Ni-Co alloy.
3. The nitrogen-doped carbon-foam metal composite material according to claim 1 or 2, characterized in that: The alumina loading on the surface of the foam metal matrix is 3.0wt% to 31.4wt%; the mass percentage of nitrogen-doped carbon nanotubes in the nitrogen-doped carbon-foam metal composite material is 4.5% to 27.0%; and the nitrogen content of the nitrogen-doped carbon nanotubes is 0.23at% to 3.5at%.
4. The nitrogen-doped carbon-foam metal composite material according to claim 1, characterized in that: Step 1) The solvothermal reaction is carried out at a temperature of 170℃~190℃ for a reaction time of 10h~15h; Step 2) The calcination is carried out at a temperature of 700℃~900℃ for a calcination time of 1h~3h.
5. A method for the co-production of ε-caprolactone and propionic acid, characterized in that, The process includes the following steps: installing the nitrogen-doped carbon-foam metal composite material as described in any one of claims 1 to 4 on the stirring shaft of the reactor, then adding cyclohexanone, propionaldehyde and organic solvent to the reactor, and then introducing oxygen to carry out the reaction, thereby obtaining a reaction solution containing ε-caprolactone and propionic acid.
6. The method for co-producing ε-caprolactone and propionic acid according to claim 5, characterized in that: The mass ratio of cyclohexanone to nitrogen-doped carbon-foam metal composite material is 1:0.001 to 0.05; the molar ratio of cyclohexanone to propionaldehyde is 1:0.1 to 10.
7. The method for co-producing ε-caprolactone and propionic acid according to claim 5 or 6, characterized in that: The pressure inside the reactor after oxygen is introduced is 0.2 MPa to 2 MPa.
8. The method for co-producing ε-caprolactone and propionic acid according to claim 5 or 6, characterized in that: The reaction was carried out at a temperature of 30℃ to 70℃ for a time of 2h to 10h.