CoPt0. 05-coated Co3O4-NC catalyst for synthesizing ethyl valerate as well as preparation method and application of CoPt0. 05-coated Co3O4-NC catalyst

Abstract

The invention discloses a CoPt0. 05-coated Co3O4-NC catalyst for synthesizing ethyl valerate as well as a preparation method and application of the CoPt0. 05-coated Co3O4-NC catalyst. The method comprises the following steps: injecting a cobalt salt solution into an organic ligand solution, stirring, centrifuging and drying to obtain ZIF-67; dispersing into an organic acid solution, stirring, centrifuging and drying to obtain CA-ZIF-67; after calcination, Co-coated Co3O4-NC is obtained; and carrying out galvanic couple replacement to obtain the CoPt < 0.05 > and Co3O4-NC. The material shows excellent performance in a reaction of synthesizing ethyl valerate through one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol, and the catalyst is simple to separate and good in cycling stability, can be reused after being washed and dried, still keeps higher catalytic activity after being used for multiple times, and has a wide application prospect. The problems of tedious steps, low efficiency, poor catalyst activity, poor stability and the like of current ethyl valerate synthesis are effectively solved, and the method has a good industrial application prospect.

Description

Technical Field

[0001] The present invention relates to a catalyst for ethyl valerate synthesis, a preparation method thereof and an application thereof, and particularly relates to a CoPt@Co3O4-NC catalyst for one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate, belonging to the technical field of biomass conversion. 0.05 Background Art

[0002] Biofuels derived from cellulosic feedstocks, as renewable alternatives to traditional fossil fuels, exhibit good application prospects. Compared with petroleum fuels, biofuels generally have lower greenhouse gas (GHG) emissions throughout their life cycle. Taking the Midwestern United States as an example, using corn stover to produce biofuels can reduce greenhouse gas emissions by approximately 2 - 16 million tons of carbon dioxide equivalent per year. Since 2010, valeric esters have been recognized as a new type of cellulosic-derived transportation biofuel (or additive) and have been named "valeric biofuels". The gasoline and diesel components provided by these emerging pentyl biofuels are fully compatible with transportation fuels. Compared with many candidate biofuels such as ethanol, γ-valerolactone (GVL), and 2-methyltetrahydrofuran (MTHF), pentyl biofuels have an acceptable energy density and a more suitable polarity. Among them, ethyl valerate (EV) stands out particularly. The results of a 250,000-kilometer road test carried out by Shell Company show that ethyl valerate has great potential for industrial application.

[0003] The synthesis technology of valeric esters (especially EV) in the past decade has mainly been based on a cascade conversion system formed by alternating hydrogenation-dehydration and acid catalysis of levulinic acid (LA). First, LA is converted to GVL through hydrogenation-dehydration or dehydration-hydrogenation reactions. Subsequently, GVL undergoes acid-catalyzed ring opening to generate a pentenoic acid intermediate, which is then selectively hydrogenated to obtain valeric acid (VA). Finally, EV is synthesized through acid-catalyzed esterification of VA (Sun P, Gao G, Zhao Z, et al. Stabilization of cobalt catalystsby embedment for efficient production of valeric biofuel[J]. ACS Catalysis, 2014, 4(11):4136 - 4142; Yu Z, Lu X, Xiong J, et al. Transformation of levulinic acidto valeric biofuels:areview on heterogeneous bifunctional catalytic systems[J].

[0004] ChemSusChem, 2019, 12(17): 3915 - 3930; The relevance of Lewis acid sites on the gas phase reaction of levulinic acid into ethyl valerate using CoSBA-xAl bifunctional catalysts[J]). The reported synthesis steps of ethyl valerate are cumbersome and inefficient, and the catalysts have poor activity and stability. Considering economic benefits, operability, and environmental friendliness, they are not the best choices for large-scale applications. Summary of the Invention

[0005] The object of the present invention is to provide a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, its preparation method, and application. The present invention uses ZIF-67 as a precursor and utilizes the characteristics of cyanuric acid to perform anisotropic etching treatment on it, prompting it to form a hollow structure with unique characteristics. Thereafter, CoPt 0.05 @Co3O4-NC is successfully prepared through pyrolysis and electrochemical replacement. The present invention can catalyze the one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate. Under the optimal reaction conditions, the conversion rate of 2-furoic acid is 100%, and the yield of ethyl valerate reaches 73.8%, solving the problems of complex existing synthesis techniques and poor catalyst stability. The reaction process involved in the present invention has the advantages of high target product yield, easy separation of the catalyst from the product, good catalyst activity and selectivity, and high repeated utilization rate.

[0006] The object of the present invention can be achieved by the following technical solutions:

[0007] A preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which consists of the following steps:

[0008] (1) Add a surfactant and a cobalt salt to deionized water, stir and dissolve to obtain a metal salt solution; add an organic ligand to deionized water, stir and dissolve to obtain an organic ligand solution;

[0009] (2) Inject the metal salt solution into the organic ligand solution, stir evenly, centrifuge to obtain a precipitate, and dry it to obtain a precursor material, namely ZIF-67;

[0010] (3) Disperse the prepared ZIF-67 in an ethanol solution of an organic acid, stir and heat, keep the temperature constant for several hours, then cool to room temperature, centrifuge to obtain a precipitate, and dry it to obtain an etched material, namely CA-ZIF-67;

[0011] (4) The prepared CA-ZIF-67 is heated up under an inert atmosphere for calcination treatment to obtain Co@Co3O4-NC material;

[0012] (5) The prepared Co@Co3O4-NC material is pickled and then dispersed in deionized water. An aqueous solution of platinum salt is added for replacement treatment under an inert atmosphere. After ultrasonic treatment for a certain time, the precipitate is collected by centrifugation and dried to obtain the described CoPt 0.05 @Co3O4-NC material.

[0013] Preferably, in step (1), the organic ligand is selected from 2-methylimidazole; the surfactant is selected from cetyltrimethylammonium bromide CTAB; the cobalt salt is selected from cobalt nitrate hexahydrate.

[0014] Preferably, in step (1), the molar ratio of the surfactant to the cobalt salt is 1:50 - 150; the concentration of the surfactant is 0.2 - 0.8 g / L, and the concentration of the cobalt salt is 0.05 - 0.5 mol / L.

[0015] Preferably, in step (1), the molar ratio of the cobalt salt to the organic ligand is 1:40 - 80; the concentration of the organic ligand is 0.1 - 10 mol / L.

[0016] Preferably, in step (2), the volume ratio of the metal salt mixed solution to the organic ligand solution is 1:5 - 10; the stirring time is 0.5 - 2 h; the drying temperature is 50 - 80 °C.

[0017] Preferably, in step (3), the organic acid is selected from cyanuric acid; the mass ratio of ZIF-67 to the organic acid is 1:1 - 2; the stirring time is 2 - 12 h; the heating temperature is 30 - 100 °C; the drying temperature is 50 - 80 °C.

[0018] Preferably, in step (4), the inert atmosphere is an argon atmosphere; the calcination treatment temperature is 300 - 800 °C, the calcination treatment time is 1 - 3 h, and the heating rate is 1 - 5 °C / min.

[0019] Preferably, in step (5), the acid used is selected from hydrochloric acid; the acid concentration is 0.001 - 0.1 mol / L; the platinum salt is selected from potassium chloroplatinate; the inert atmosphere is a nitrogen atmosphere; the concentration of Co@Co3O4-NC dispersed in deionized water after pickling is 0.1 - 2.0 g / L; the concentration of the aqueous solution of the platinum salt is 1.0 - 100 g / L; the mass ratio of Co@Co3O4-NC to the platinum salt is 1:1 - 5; the replacement treatment time is 0 - 2 h.

[0020] A CoPt with a core-shell structure is prepared by the above preparation method 0.05 @Co3O4-NC catalyst.

[0021] The present invention also provides an application of the CoPt 0.05 @Co3O4-NC catalyst in the one-pot esterification-hydrogenolysis synthesis of ethyl valerate from 2-furoic acid and ethanol (attached Figure 1 ), and the catalyst is the CoPt 0.05 @Co3O4-NC prepared by the above preparation method.

[0022] The specific method is as follows: 2-furoic acid, absolute ethanol, and CoPt 0.05 @Co3O4-NC catalyst are sequentially added into a reaction kettle, hydrogen is introduced, stirred and heated to 70-200 °C, and after constant temperature reaction for 12-60 h, it is cooled to room temperature. The CoPt 0.05 @Co3O4-NC catalyst is separated from the reaction system by centrifugation to obtain ethyl valerate. The dosage of the absolute ethanol is 2-5 mL; the dosage ratio of the 2-furoic acid to the CoPt 0.05 @Co3O4-NC catalyst is 1 g:(2 g-0.1 g).

[0023] Compared with the prior art, the technical effects of the present invention are as follows:

[0024] (1) By using the MOFs-mediated etching-pyrolysis-displacement strategy, the CoPt 0.05 @Co3O4-NC catalyst is successfully prepared. The catalyst system presents a hollow nanobox structure with three-dimensional orthorhombic channels, and CoPt 0.05 @Co3O4 core-shell nanoparticles are uniformly distributed inside. Among them, the hollow structure can improve the catalytic activity by optimizing the accessibility of metal active sites. The synergistic effect between metals can further promote the esterification-hydrogenolysis reaction. The synergistic regulation of both structure and composition can significantly improve the reaction activity and selectivity.

[0025] (2) The CoPt 0.05 @Co3O4-NC catalyst involved in the synthesis of ethyl valerate has high catalytic activity and good selectivity. Under the optimal reaction conditions, the conversion rate of 2-furoic acid is 100%, and the yield of ethyl valerate reaches 73.8%, solving the problems of complex steps and poor catalyst stability in the existing synthesis technology. Description of the Drawings

[0026] Figure 1 is the reaction formula for the one-pot esterification-hydrogenolysis synthesis of ethyl valerate from 2-furoic acid and ethanol catalyzed by the CoPt 0.05 @Co3O4-NC material;

[0027] Figure 2 It is the scanning electron microscope image (SEM) of ZIF-67 obtained in Examples 1 to 6;

[0028] Figure 3 It is the scanning electron microscope image (SEM) of CA-ZIF-67 prepared in Examples 1, 7 to 11;

[0029] Figure 4 It is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Examples 1, 12 to 16;

[0030] Figure 5 It is 1#CoPt prepared in Examples 1, 17 to 21 0.05 @Co3O4-NC scanning electron microscope image (SEM);

[0031] Figure 6 It is 1#CoPt prepared in Example 1 0.05 @Co3O4-NC material for the performance graph of the one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate;

[0032] Figure 7 It is the gas chromatography-mass spectrometry graph of Example 22;

[0033] Figure 8 It is 1#CoPt prepared in Example 1 0.05 @Co3O4-NC material for the cyclic test graph of the one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate. Detailed implementation mode

[0034] The present invention will be further described below by examples, but the patent rights are not limited to these examples.

[0035] Example 1

[0036] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, including the following steps:

[0037] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, and after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 1# CoPt 0.05 @Co3O4-NC material).

[0038] Figure 2 In (a) is the scanning electron microscope image (SEM) of ZIF-67 prepared in Example 1;

[0039] Figure 3 In (a) is the scanning electron microscope image (SEM) of CA-ZIF-67 prepared in Example 1;

[0040] Figure 4 In (a) is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Example 1;

[0041] Figure 5 In (a) is 1# CoPt prepared in Example 1 0.05 @Co3O4-NC scanning electron microscope image (SEM).

[0042] Example 2

[0043] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, including the following steps:

[0044] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (234 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 30 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, and after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 2#CoPt 0.05 @Co3O4-NC material).

[0045] Figure 2 Figure (b) in is the scanning electron microscope image (SEM) of ZIF-67 prepared in Example 2.

[0046] Example 3

[0047] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0048] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (8 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (3.63 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 50 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 3# CoPt 0.05 @Co3O4-NC material).

[0049] Figure 2 Figure (c) in [reference] is the scanning electron microscope (SEM) image of ZIF-67 prepared in Example 3.

[0050] Example 4

[0051] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0052] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (8 mg) and cobalt(II) nitrate hexahydrate (234 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution. 2-Methylimidazole (3.63 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution. The metal salt solution was rapidly injected into the organic ligand solution, stirred for 30 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67. 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid. 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred, and heated at 60 °C. After reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67. The prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain the Co@Co3O4-NC material. 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, it was centrifuged to collect the precipitate and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 4# CoPt 0.05 @Co3O4-NC material).

[0053] Figure 2 Figure (d) is the scanning electron microscope image (SEM) of ZIF-67 prepared in Example 4.

[0054] Example 5

[0055] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0056] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (8 mg) and cobalt(II) nitrate hexahydrate (234 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 50 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 5# CoPt 0.05 @Co3O4-NC material).

[0057] Figure 2 Figure (e) is a scanning electron microscope image (SEM) of the ZIF-67 prepared in Example 5.

[0058] Example 6

[0059] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0060] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (3.63 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 6#CoPt 0.05 @Co3O4-NC material).

[0061] Figure 2 Figure (f) is the scanning electron microscope image (SEM) of ZIF-67 prepared in Example 6. From Figure 2 the scanning electron microscope images (SEM) of ZIF-67 obtained from Examples 1 to 6 corresponding to (a) to (f) in the figure, it can be seen that the material has a nano-cubic morphology, with a size of about 500 - 900 nm, and the surface is smooth and the size is uniform.

[0062] Example 7

[0063] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0064] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 50 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 60 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, and after reacting at a constant temperature for 8 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 7#CoPt 0.05 @Co3O4-NC material).

[0065] Figure 3 Figure (b) in is the scanning electron microscope image (SEM) of CA-ZIF-67 prepared in Example 7.

[0066] Example 8

[0067] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0068] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 70 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 40 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, and after reacting at a constant temperature for 6 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 8#CoPt 0.05 @Co3O4-NC material).

[0069] Figure 3 Figure (c) is the scanning electron microscope image (SEM) of the CA-ZIF-67 prepared in Example 8.

[0070] Example 9

[0071] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0072] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was rapidly injected into the organic ligand solution, stirred for 40 min, the precipitate was collected by centrifugation, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 40 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 6 h, it was cooled to room temperature, the precipitate was collected by centrifugation, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 9# CoPt 0.05 @Co3O4-NC material).

[0073] Figure 3 Figure (d) is the scanning electron microscope image (SEM) of CA-ZIF-67 prepared in Example 9.

[0074] Example 10

[0075] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0076] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was rapidly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 70 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 60 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, cooled to room temperature after reacting at a constant temperature for 2 h, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 10#CoPt 0.05 @Co3O4-NC material).

[0077] Figure 3 Figure (e) is a scanning electron microscope image (SEM) of the CA-ZIF-67 prepared in Example 10.

[0078] Example 11

[0079] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0080] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 50 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 11#CoPt 0.05 @Co3O4-NC material).

[0081] Figure 3 Figure (f) is the scanning electron microscope image (SEM) of the CA-ZIF-67 prepared in Example 11; Figure 3 Figures (a)-(f) are the scanning electron microscope images (SEM) of the CA-ZIF-67 obtained in Examples 1, 7-11. It can be seen from the figure that the material has a nano-cubic morphology with uniform size.

[0082] Example 12

[0083] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, comprising the following steps:

[0084] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution. 2-Methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution. The metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67. 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid. 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred, and heated at 60 °C. After reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67. The prepared CA-ZIF-67 was calcined at 700 °C for 3 h in an argon atmosphere at a heating rate of 2 °C / min to obtain the Co@Co3O4-NC material. 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, it was centrifuged to collect the precipitate and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 12#CoPt 0.05 @Co3O4-NC material).

[0085] Figure 4 Figure (b) in it is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Example 12.

[0086] Example 13

[0087] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0088] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, cooled to room temperature after reacting at a constant temperature for 4 h, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 800 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain the Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 13#CoPt 0.05 @Co3O4-NC material).

[0089] Figure 4 Figure (c) is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Example 13.

[0090] Example 14

[0091] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0092] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, cooled to room temperature after reacting at a constant temperature for 4 h, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 1 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 14#CoPt 0.05 @Co3O4-NC material).

[0093] Figure 4 Figure (d) in it is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Example 14.

[0094] Example 15

[0095] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0096] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, cooled to room temperature after reacting at a constant temperature for 4 h, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 800 °C for 3 h in an argon atmosphere at a heating rate of 2 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 15#CoPt 0.05 @Co3O4-NC material).

[0097] Figure 4 Figure (e) is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Example 15.

[0098] Example 16

[0099] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, including the following steps:

[0100] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, and 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, and after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 700 °C for 1 h in an argon atmosphere at a heating rate of 2 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 16#CoPt 0.05 @Co3O4-NC material).

[0101] Figure 4 In (f) is the scanning electron microscope image (SEM) of Co@Co3O4-NC prepared in Example 16; Figure 4 In (a)-(f) are the scanning electron microscope images (SEM) of Co@Co3O4-NC obtained in Examples 1, 12-16. It can be seen from the figure that the material has a nano-cubic morphology and a rough surface.

[0102] Example 17

[0103] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, including the following steps:

[0104] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, cooled to room temperature after reacting at a constant temperature for 4 h, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 15 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 2 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 17#CoPt 0.05 @Co3O4-NC material).

[0105] Figure 5 In (b) is the scanning electron microscope image (SEM) of 17#CoPt 0.05 @Co3O4-NC prepared in Example 17.

[0106] Example 18

[0107] This example provides a preparation method of a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, which includes the following steps:

[0108] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was rapidly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 30 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 10 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 18#CoPt 0.05 @Co3O4-NC material).

[0109] Figure 5 In (c) is the scanning electron microscope image (SEM) of 18#CoPt 0.05 @Co3O4-NC prepared in Example 18.

[0110] Example 19

[0111] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, which includes the following steps:

[0112] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 20 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 1 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 19#CoPt 0.05 @Co3O4-NC material).

[0113] Figure 5 In (d) is the scanning electron microscope image (SEM) of 19#CoPt 0.05 @Co3O4-NC prepared in Example 19.

[0114] Example 20

[0115] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for the synthesis of ethyl valerate, comprising the following steps:

[0116] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was quickly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 15 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 5 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 20#CoPt 0.05 @Co3O4-NC material).

[0117] Figure 5 In (e) is the scanning electron microscope image (SEM) of 20#CoPt 0.05 @Co3O4-NC prepared in Example 20.

[0118] Example 21

[0119] This example provides a method for preparing a CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, comprising the following steps:

[0120] In a 250 mL beaker, cetyltrimethylammonium bromide (CTAB) (4 mg) and cobalt(II) nitrate hexahydrate (292 mg) were added to 10 mL of deionized water and stirred until dissolved to obtain a metal salt solution; 2-methylimidazole (4.54 g) was added to 70 mL of deionized water and stirred until dissolved to obtain an organic ligand solution; the metal salt solution was rapidly injected into the organic ligand solution, stirred for 40 min, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain ZIF-67; 60 mg of cyanuric acid was dissolved in 50 mL of ethanol to obtain an ethanol solution of cyanuric acid, 50 mg of the prepared ZIF-67 was dispersed in the ethanol solution of cyanuric acid, stirred and heated at 60 °C, after reacting at a constant temperature for 4 h, it was cooled to room temperature, centrifuged to collect the precipitate, and dried at 80 °C for 24 h to obtain the etched material, namely CA-ZIF-67; the prepared CA-ZIF-67 was calcined at 600 °C for 2 h in an argon atmosphere at a heating rate of 5 °C / min to obtain Co@Co3O4-NC material; 30 mg of the pickled Co@Co3O4-NC material was dispersed in 30 mL of deionized water, and 10 mL of an aqueous solution of potassium chloroplatinate with a concentration of 1 mg / mL was added for replacement treatment under a nitrogen atmosphere. After ultrasonic treatment for 30 min, the precipitate was collected by centrifugation and dried at 70 °C for 12 h to obtain the CoPt 0.05 @Co3O4-NC material (labeled as 21#CoPt 0.05 @Co3O4-NC material).

[0121] Figure 5 In (f) is the scanning electron microscope image (SEM) of 21#CoPt 0.05 @Co3O4-NC prepared in Example 21; Figure 5 In (a)-(f) are the scanning electron microscope images (SEM) of CoPt 0.05 @Co3O4-NC obtained in Examples 1, 17-21. It can be seen from the figure that the material has a nano-cubic morphology and a rough surface.

[0122] Example 22

[0123] Based on the application of 1#CoPt 0.05 @Co3O4-NC material in the one-pot esterification-hydrogenolysis reaction of 2-furoic acid and ethanol to synthesize ethyl valerate.

[0124] In a reaction kettle, 0.05 mmol of 2-furoic acid, 4 mL of absolute ethanol, and 0.05 g of the catalyst (1#CoPt 0.05 @Co3O4-NC material prepared in Example 1) were successively added, hydrogen was charged at 1 MPa, stirred and heated to the reaction temperature of 180 °C, and reacted at a constant temperature for a period of time. After the reaction was completed, 1#CoPt 0.05@Co3O4-NC material, the reaction solution was analyzed by gas chromatography-mass spectrometry.

[0125] Figure 6 is the 1# CoPt prepared in Example 1 0.05 Performance graph of @Co3O4-NC material catalyzing the one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate. Among them, at 60 h of this reaction, the conversion rate of 2-furoic acid was 100%, and the yield of ethyl valerate reached 73.8%.

[0126] Figure 7 is the gas chromatography-mass spectrometry graph of this example. It can be seen from the graph that in the case of ignoring the solvent, the target product ethyl valerate was detected in the reaction mixture at 4.5 min of the instrument operation, and basically no raw material 2-furoic acid was detected, indicating that 2-furoic acid was almost completely converted under the given reaction conditions. In addition, a small amount of ethyl 2-hydroxyvalerate was detected, indicating that the selectivity of ethyl valerate in this reaction system was relatively high.

[0127] Example 23

[0128] Based on 1# CoPt 0.05 Application of @Co3O4-NC material in the reaction of one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate.

[0129] In the reaction kettle, 0.05 mmol of 2-furoic acid, 4 mL of absolute ethanol, and 0.05 g of catalyst (1# CoPt prepared in Example 1 0.05 @Co3O4-NC material) were added in sequence, 1 MPa of hydrogen was charged, and the mixture was stirred and heated to the reaction temperature of 180 °C and kept at a constant temperature for 60 hours. After the reaction, the 1# CoPt 0.05 @Co3O4-NC material was separated by centrifugation, and the reaction solution was analyzed by gas chromatography-mass spectrometry. The separated catalyst was washed with ethanol and water for several times and then directly applied to the next catalytic reaction. Except for using the recycled catalyst, other specific reaction conditions remained unchanged.

[0130] Figure 8 is the 1# CoPt prepared in Example 1 0.05 Cyclic test graph of @Co3O4-NC material catalyzing the one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate. The activity of the catalyst did not show an obvious decline within 10 cycles, indicating good stability.

[0131] It should be understood that the detailed description of the technical solution of the present invention by means of the optimized embodiments above is illustrative rather than restrictive. It cannot be determined that the specific implementation manners of the present invention are limited to this. For those of ordinary skill in the technical field to which the present invention pertains, without departing from the concept of the present invention, modifying the technical solutions recorded in each embodiment or equivalently replacing some of the technical features should all be regarded as belonging to the scope of patent protection determined by the claims submitted for the present invention.

Claims

1. A preparation method of CoPt 0.05 @Co3O4-NC catalyst for ethyl valerate synthesis, characterized in that Specifically, it includes the following steps: (1) Add surfactant and cobalt salt into deionized water, stir and dissolve to obtain a metal salt solution; add the organic ligand into deionized water, stir and dissolve to obtain an organic ligand solution; (2) Inject the metal salt solution described in step (1) into the organic ligand solution, stir evenly, centrifuge to obtain the precipitate, and dry it to obtain the precursor material, namely ZIF-67; (3) Disperse the ZIF-67 obtained in step (2) in an ethanol solution of organic acid, stir and heat, cool to room temperature after reacting at a constant temperature for several hours, centrifuge to obtain the precipitate, and dry it to obtain the etched material, namely CA-ZIF-67; (4) Heat the CA-ZIF-67 obtained in step (3) under an inert atmosphere for calcination treatment to obtain Co@Co3O4-NC material; (5) The Co@Co3O4-NC material obtained in step (4) is pickled and then dispersed in deionized water. An aqueous solution of a platinum salt is added for replacement treatment under an inert atmosphere. After ultrasonic treatment, the precipitate is collected by centrifugation and dried to obtain the CoPt 0.05 @Co3O4-NC material.

2. CoPt for ethyl valerate synthesis according to claim 1 0.05 @Preparation method of Co3O4-NC catalyst, characterized in that In step (1), the organic ligand is selected from 2-methylimidazole; the surfactant is selected from cetyltrimethylammonium bromide CTAB; the cobalt salt is selected from cobalt nitrate hexahydrate.

3. CoPt for ethyl valerate synthesis according to claim 1 0.05 @Preparation method of Co3O4-NC catalyst, characterized in that In step (1), the molar ratio of the surfactant to the cobalt salt is 1:50 - 150; the concentration of the surfactant in the metal salt solution is 0.2 - 0.8 g / L, the concentration of the cobalt salt in the metal salt solution is 0.05 - 0.5 mol / L; the molar ratio of the cobalt salt to the organic ligand is 1:40 - 80; the concentration of the organic ligand in the metal salt solution is 0.1 - 10 mol / L.

4. CoPt for ethyl valerate synthesis according to claim 1 0.05 @Preparation method of Co3O4-NC catalyst, characterized in that In step (2), the volume ratio of the metal salt solution to the organic ligand solution is 1:5 - 10; the stirring time is 0.5 - 2 h; the drying temperature is 50 - 80 °C.

5. CoPt for ethyl valerate synthesis according to claim 1 0.05 @ Preparation method of Co3O4-NC catalyst, characterized in that In step (3), the organic acid is selected from cyanuric acid; the mass ratio of ZIF-67 to the organic acid is 1:1 - 2; the stirring time is 2 - 12 h; the heating temperature is 30 - 100 °C; the drying temperature is 50 - 80 °C.

6. CoPt for ethyl valerate synthesis according to claim 1 0.05 @Preparation method of Co3O4-NC catalyst, characterized in that In step (4), the inert atmosphere is an argon atmosphere; the calcination treatment temperature is 300 - 800 °C, the calcination treatment time is 1 - 3 h, and the heating rate is 1 - 5 °C / min.

7. CoPt for ethyl valerate synthesis according to claim 1 0.05 @ Preparation method of Co3O4-NC catalyst, characterized in that In step (5), the acid used in the pickling is selected from hydrochloric acid; the acid concentration is 0.001 - 0.1 mol / L; the platinum salt is selected from potassium chloroplatinate; the inert atmosphere is a nitrogen atmosphere; the concentration of Co@Co3O4-NC dispersed in deionized water after pickling is 0.1 - 2.0 g / L; the aqueous solution concentration of the platinum salt is 1.0 - 100 g / L; the mass ratio of Co@Co3O4-NC to the platinum salt is 1:1 - 5; the replacement treatment time is 0 - 2 h.

8. CoPt prepared by the preparation method according to any one of claims 1 to 7 0.05 @Co3O4-NC catalyst.

9. The CoPt as claimed in claim 8 0.05 @ Application of the Co3O4-NC catalyst in the one-pot esterification-hydrogenolysis of 2-furoic acid and ethanol to synthesize ethyl valerate.

10. The application according to claim 9, characterized in that, Add 2-furoic acid, anhydrous ethanol, and CoPt into the reactor in sequence 0.05 @Co3O4-NC catalyst, introduce hydrogen gas, stir and heat to 70 - 200 °C, keep the temperature constant for reaction for 12 - 60 h, then cool to room temperature, and separate the CoPt 0.05 @Co3O4-NC catalyst from the reaction system by centrifugation to obtain ethyl valerate; The dosage of the absolute ethanol is 2 to 5 mL; the dosage ratio of the 2-furoic acid to the CoPt 0.05 @Co3O4-NC catalyst is 1 g : (2 g to 0.1 g).

Images