Carbon-coated cobalt catalyst, preparation method thereof and application of carbon-coated cobalt catalyst in preparation of cyclopentanol through furfural water-phase hydrogenation

Abstract

The invention belongs to the technical field of fine chemical engineering, and particularly relates to a carbon-coated cobalt catalyst, a preparation method of the carbon-coated cobalt catalyst and application of the carbon-coated cobalt catalyst to preparation of cyclopentanol through furfural water-phase hydrogenation. According to the method, Co < 2 + > and an organic ligand containing an oxygen functional group are subjected to a coordination reaction, so that hydroxyl and carboxyl are connected with Co nanoparticles to prepare an MOF precursor, and then the MOF precursor is subjected to pyrolysis to form a Co-C structure. The obtained Co-C has the characteristics of low particle size and large specific surface area, has high hydrothermal stability, is not easy to agglomerate, is used for catalyzing a furfural water phase hydrogenation reaction, can enable a main product to be cyclopentanone and improve the conversion rate of furfural by controlling the pyrolysis temperature, and can directly synthesize a cyclopentanol product with high additional value from furfural in one step. Meanwhile, the Co-C catalyst has good cycling stability in the furfural water phase hydrogenation reaction, has renewability, and has a wide industrial application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of fine chemical industry, and particularly relates to a carbon-coated cobalt catalyst, a preparation method thereof and application thereof in preparing cyclopentanol by aqueous phase hydrogenation of furfural. Background Art

[0002] With global warming and the continuous consumption of energy, the efficient use of renewable biomass resources widely existing in nature to replace fossil energy has become a hot issue. Furfural is an important biomass platform, derived from lignin cellulose and hemicellulose in plants. It is mainly composed of lignin, cellulose and hemicellulose, and can be further converted into fuels, fuel additives and other high value-added chemicals, such as furfuryl alcohol, tetrahydrofurfuryl alcohol, alcohol, cyclopentanone, cyclopentanol, dimethylfuran, dimethyltetrahydrofuran, pentanediol, levulinic acid, etc. At present, furfural is mainly used in the industrial production of furfuryl alcohol, but there are still some problems in the industrial production of downstream products, such as low selectivity and difficulty in product separation, which limit its industrial application. Therefore, further expanding the utilization of furfural has important strategic value.

[0003] Cyclopentanone and cyclopentanol are raw materials for many fine chemicals, and are used to synthesize fungicides, rubbers, and aromatics. In industry, the preparation of cyclopentanone and cyclopentanol mainly adopts the gas phase catalytic cyclization method. However, this method has complex production process, harsh conditions, serious pollution, and excessive reliance on non-renewable fossil energy. Therefore, it is urgent to study a green and sustainable production process of cyclopentanone and cyclopentanol.

[0004] Starting from furfural, the selective conversion of furfural to cyclopentanone and cyclopentanol can be achieved by utilizing the interaction between metal active centers and catalyst supports through the regulation of different catalytic systems. However, currently, metal catalysts are mainly used for the selective hydrogenation of furfural, such as non-precious metal catalysts such as Cu and Ni and supported precious metal catalysts. Although precious metal-based catalysts have strong H 2 The furan ring has a strong adsorption capacity, but due to the strong adsorption capacity of the furan ring, side reactions are prone to occur, and tetrahydrofuran alcohol is generated, which is not economical, and will cause the rearrangement of furfural to cyclopentanone and cyclopentanol. There are also problems such as expensive loaded metals, high hydrogen pressure, long reaction time, unstable metal nanoparticles in water and easy agglomeration, and low catalyst reusability. Among them, Co-based catalysts can strongly polarize the carbon-oxygen double bond without affecting the furan ring, which is beneficial to the selective hydrogenation of furfural to furfuryl alcohol, and Co-based catalysts have excellent ring opening and closing capabilities in the five-membered ring reaction. However, the current Co-based catalysts still have problems such as large particle size and the main product is cyclopentanone.

[0005] MOF has controllable specific surface area and pore structure, and MOF-derived carbon-coated materials have excellent performance and have been widely used in the field of catalysis. Therefore, if a MOF-derived porous carbon material can be developed for use in the reaction of furfural rearrangement to cyclopentanol, it is expected to improve the current shortcomings of furfural aqueous hydrogenation reaction. Summary of the invention

[0006] In order to overcome the deficiencies of the above-mentioned prior art, the present invention provides a Co-modified MOF-derived Co@C material, which is used to catalyze the aqueous phase hydrogenation reaction of furfural, so that the main product can be cyclopentanol, thereby solving the problem that the prior art cannot prepare cyclopentanol from furfural in one step and the metal nanoparticles are unstable and easy to agglomerate in water.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is:

[0008] The first aspect of the present invention provides a method for preparing a carbon-coated cobalt catalyst, the method comprising the following steps:

[0009] S1. Dissolve the Co source in water, dissolve the organic ligand containing oxygen functional groups in an organic solvent, combine the two solutions, fully disperse them, and then perform a hydrothermal reaction to obtain a precursor of the Co-modified MOF material;

[0010] S2. The precursor of S1 is dried and placed in a gas atmosphere for pyrolysis treatment to obtain a Co-modified MOF-derived Co@C catalyst material.

[0011] The present invention uses MOF as a precursor and forms a carbon-cobalt structured catalyst after pyrolysis. The obtained catalyst has the characteristics of low particle size and large specific surface area after pyrolysis, is low in price, is renewable, and has broad prospects for industrial application.

[0012] Preferably, the Co source includes cobalt acetate, cobalt chloride, cobalt oxalate, cobalt carbonate, cobalt sulfate, and cobalt nitrate, and the organic ligand containing oxygen functional groups is 2,5-dihydroxyterephthalic acid.

[0013] Preferably, the organic solvent comprises tetrahydrofuran or N,N-dimethylformamide, preferably tetrahydrofuran.

[0014] Preferably, the molar ratio of Co to organic ligand in the Co source is 0.5-2:1.

[0015] Preferably, the hydrothermal reaction temperature is 100-150°C and the time is 24-96 hours, preferably 110°C and 72 hours.

[0016] Preferably, the temperature of the pyrolysis treatment is 400-600°C, the time is 1-3h, and the heating rate is 4-6°C / min.

[0017] Preferably, the gas atmosphere includes hydrogen atmosphere, argon atmosphere, nitrogen atmosphere, and the gas flow rate is 40-60 mL / min, preferably argon atmosphere, and the argon flow rate is 40 mL / min.

[0018] The second aspect of the present invention provides a carbon-coated cobalt catalyst prepared by the preparation method described in the first aspect.

[0019] The third aspect of the present invention provides the use of the carbon-coated cobalt catalyst described in the second aspect in the aqueous phase hydrogenation reaction of furfural.

[0020] The fourth aspect of the present invention provides a method for preparing cyclopentanol by aqueous phase hydrogenation of furfural, which specifically comprises: adding furfural, water and the carbon-coated cobalt catalyst described in the second aspect into a reactor, replacing the air in the reactor, introducing hydrogen to an initial pressure of 1-6 MPa, and then conducting a catalytic selective hydrogenation reaction under stirring, wherein the ratio of furfural to catalyst is 3-5 mmol: 20-300 mg, the reaction temperature is 120-200°C, and the reaction time is 30-720 min.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention converts Co 2+ The organic ligand with oxygen-containing functional groups is used to connect hydroxyl and carboxyl groups with Co nanoparticles through coordination reaction to form a MOF precursor, and then pyrolyze to form a Co@C structure. The obtained Co@C has the characteristics of low particle size and large specific surface area, and has high hydrothermal stability and is not easy to agglomerate. It is used to catalyze the aqueous phase hydrogenation reaction of furfural. By controlling the pyrolysis temperature, the main product can be cyclopentanone, and the conversion rate of furfural is improved, and a high value-added cyclopentanol product can be directly synthesized from furfural in one step. At the same time, the Co@C catalyst has good cycle stability in the aqueous phase hydrogenation reaction of furfural, is renewable, and has broad prospects for industrial application. In general, the present invention has the following advantages:

[0023] (1) The carbon-coated cobalt-supported catalyst provided by the present invention has a smaller particle size and better dispersion, can provide more adsorption sites and active sites for the catalytic reaction, and increase the contact area between the reactants and the active metal, thereby having higher catalytic activity and conversion efficiency. When applied to the aqueous phase hydrogenation reaction of furfural, the main product can be cyclopentanone, and the conversion rate of furfural can be improved.

[0024] (2) The cobalt metal catalyst in the carbon-coated cobalt catalyst provided by the present invention has strong hydrogenation ability and good ring-closing ability in the synthesis of the five-membered ring, and the carbon material has high hydrothermal stability, and can form a physical barrier outside the cobalt nanoparticles to hinder the further growth of the metal nanoparticles. Thereby, the cyclic stability of the carbon-coated cobalt catalyst in the furfural aqueous phase hydrogenation reaction is enhanced, making it renewable and reusable, saving costs.

[0025] (3) In the preparation of cyclopentanol, the present invention uses furfural as a raw material and non-precious metal cobalt as a catalyst, so that the active intermediate completes a series of cascade reactions such as hydrogenation, rearrangement and ring opening on the catalyst surface, thereby directly synthesizing a high-value-added cyclopentanol product from furfural in one step. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 X-ray diffraction analysis diagram of carbon-coated cobalt catalyst at different pyrolysis temperatures in Examples 1-5;

[0027] Figure 2 The infrared spectra of the carbon-coated cobalt catalyst at different pyrolysis temperatures in Examples 1-5;

[0028] Figure 3 The performance data of the carbon-coated cobalt catalyst for the aqueous phase hydrogenation of furfural at different pyrolysis temperatures in Examples 6-9;

[0029] Figure 4 The performance data of furfural aqueous phase hydrogenation catalyzed by carbon-coated cobalt catalysts at different hydrogen pressures in Examples 10-12;

[0030] Figure 5 Electron micrographs of furfural aqueous phase hydrogenation catalyzed by carbon-coated cobalt catalyst Co@C-500 after multiple cycles (ac is the electron micrograph after the first catalysis, d is the particle size distribution after the first catalysis; eg is the electron micrograph after the sixth cycle catalysis, h is the particle size distribution after the sixth cycle catalysis);

[0031] Figure 6 This is the performance diagram of the carbon-coated cobalt catalyst Co@C-500 after multiple cycles of catalytic furfural aqueous phase hydrogenation. DETAILED DESCRIPTION

[0032] The specific embodiments of the present invention are further described below. It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0033] The experimental methods in the following examples are conventional methods unless otherwise specified, and the experimental materials used in the following examples are commercially available unless otherwise specified.

[0034] Example 1: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0035] Weigh 0.3g furfural and 10mL water, and put them into an intermittent closed high-pressure reactor, and then add 0.1g catalyst Co@C-400 (where 400 is the pyrolysis temperature of the Co-MOF precursor in an argon atmosphere). After replacing the air in the reactor with nitrogen 3-4 times, introduce hydrogen to an initial pressure of 2MPa, turn on the stirring device, and control the stirring speed at about 400r / min, then react at 160°C for 8 hours, cool after the reaction, and obtain the product after filtration and centrifugation. Finally, gas chromatography-mass spectrometry is used to quantitatively and qualitatively analyze the product.

[0036] Wherein, the Co@C-400 catalyst is prepared by the following method:

[0037] Weigh 0.531 g of cobalt acetate [(CH 3 CO 2 ) 2 Co】 was dissolved in 10 mL of deionized water, and 0.297 g of 2,5-dihydroxyterephthalic acid (C 8 H 6 O 6 ) was dissolved in 10 mL of tetrahydrofuran, the two solutions were mixed until clear, and then transferred to a 50 mL Teflon hydrothermal autoclave and kept at 110 ° C for 72 h. After the hydrothermal reaction, it was repeatedly washed with tetrahydrofuran for 3 times and then dried in a vacuum at 90 ° C. Finally, it was transferred to an argon atmosphere, heated to 400 ° C at a heating rate of 5 ° C / min, and pyrolyzed for 1 h to obtain the product.

[0038] Example 2: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0039] Weigh 0.3g furfural and 10mL water, put them into the reactor, and then add 0.1g catalyst Co@C-450 (where 450 is the pyrolysis temperature of the Co-MOF precursor in an argon atmosphere). After replacing the air in the reactor with nitrogen 3-4 times, introduce hydrogen to an initial pressure of 2MPa, turn on the stirring device, and control the stirring speed at about 400r / min, then react at 160°C for 8 hours, cool after the reaction, and obtain the product after filtration and centrifugation. Finally, gas chromatography-mass spectrometry is used to quantitatively and qualitatively analyze the product.

[0040] The Co@C-450 catalyst was prepared by the following method:

[0041] Weigh 0.531 g of (CH 3 CO 2 ) 2 Co was dissolved in 10 mL of deionized water, and 0.297 g of C 8 H 6 O 6 Dissolve in 10 mL of tetrahydrofuran, mix the two solutions until clear, transfer to a 50 mL Teflon hydrothermal autoclave, and keep at 110 ° C for 72 hours. After the hydrothermal reaction, wash it repeatedly with tetrahydrofuran for 3 times, and then place it in a vacuum dryer at 90 ° C. Finally, transfer it to an argon atmosphere, heat it to 450 ° C at a heating rate of 5 ° C / min, and pyrolyze it for 1 hour.

[0042] Example 3: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0043] Weigh 0.3g furfural and 10mL water, put them into the reactor, and then add 0.1g catalyst Co@C-500 (where 500 is the pyrolysis temperature of the Co-MOF precursor in an argon atmosphere). After replacing the air in the reactor with nitrogen 3-4 times, introduce hydrogen to an initial pressure of 2MPa, turn on the stirring device, and control the stirring speed at about 400r / min, then react at 160°C for 8 hours, cool after the reaction, and obtain the product after filtration and centrifugation. Finally, gas chromatography-mass spectrometry is used to quantitatively and qualitatively analyze the product.

[0044] The Co@C-500 catalyst was prepared by the following method:

[0045] Weigh 0.531 g of (CH 3 CO 2 ) 2 Co was dissolved in 10 mL of deionized water, and 0.297 g of C 8 H 6 O 6 Dissolve in 10 mL of tetrahydrofuran, mix the two solutions until clear, transfer to a 50 mL Teflon hydrothermal autoclave, and keep at 110 ° C for 72 hours. After the hydrothermal, wash it repeatedly with tetrahydrofuran for 3 times, and then place it in a vacuum dryer at 90 ° C. Finally, transfer it to an argon atmosphere, heat it to 500 ° C at a heating rate of 5 ° C / min, and pyrolyze it for 1 hour.

[0046] Example 4: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0047] Weigh 0.3g furfural and 10mL water, put them into the reactor, and then add 0.1g catalyst Co@C-550 (where 550 is the pyrolysis temperature of the Co-MOF precursor in an argon atmosphere). After replacing the air in the reactor with nitrogen 3-4 times, introduce hydrogen to an initial pressure of 2MPa, turn on the stirring device, and control the stirring speed at about 400r / min, then react at 160°C for 8 hours, cool after the reaction, and obtain the product after filtration and centrifugation. Finally, gas chromatography-mass spectrometry is used to quantitatively and qualitatively analyze the product.

[0048] The Co@C-550 catalyst was prepared by the following method:

[0049] Weigh 0.531 g of (CH 3 CO 2 ) 2 Co was dissolved in 10 mL of deionized water, and 0.297 g of C 8 H 6 O 6 Dissolve in 10 mL of tetrahydrofuran, mix the two solutions until clear, transfer to a 50 mL Teflon hydrothermal autoclave, and keep at 110 ° C for 72 hours. After the hydrothermal reaction, wash it repeatedly with tetrahydrofuran for 3 times, and then place it in a vacuum dryer at 90 ° C. Finally, transfer it to an argon atmosphere, heat it to 550 ° C at a heating rate of 5 ° C / min, and pyrolyze it for 1 hour.

[0050] Example 5: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0051] Weigh 0.3g furfural and 10mL water, put them into the reactor, and then add 0.1g catalyst Co@C-600 (where 600 is the pyrolysis temperature of the Co-MOF precursor in an argon atmosphere). After replacing the air in the reactor with nitrogen 3-4 times, introduce hydrogen to an initial pressure of 2MPa, turn on the stirring device, and control the stirring speed to about 400r / min, then react at 160°C for 8 hours, cool after the reaction, and obtain the product after filtration and centrifugation. Finally, gas chromatography-mass spectrometry is used to quantitatively and qualitatively analyze the product.

[0052] The Co@C-600 catalyst was prepared by the following method:

[0053] Weigh 0.531 g of (CH 3 CO 2 ) 2 Co was dissolved in 10 mL of deionized water, and 0.297 g of C 8 H 6 O 6Dissolve in 10 mL of tetrahydrofuran, mix the two solutions until clear, transfer to a 50 mL Teflon hydrothermal autoclave, and keep at 110 ° C for 72 hours. After the hydrothermal reaction, wash it repeatedly with tetrahydrofuran for 3 times, and then place it in a vacuum dryer at 90 ° C. Finally, transfer it to an argon atmosphere, heat it to 600 ° C at a heating rate of 5 ° C / min, and pyrolyze it for 1 hour.

[0054] Example 6: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0055] The preparation process and reaction conditions are the same as those in Example 3, except that the pyrolysis temperature is 140°C.

[0056] Example 7: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0057] The preparation process and reaction conditions are the same as those in Example 3, except that the pyrolysis temperature is 160°C.

[0058] Example 8: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0059] The preparation process and reaction conditions are the same as those in Example 3, except that the pyrolysis temperature is 180°C.

[0060] Example 9: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0061] The preparation process and reaction conditions are the same as those in Example 3, except that the pyrolysis temperature is 200°C.

[0062] Example 10: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0063] The preparation process and reaction conditions are the same as those in Example 3, except that the hydrogen pressure is 3 MPa.

[0064] Example 11: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0065] The preparation process and reaction conditions are the same as those in Example 3, except that the hydrogen pressure is 4 MPa.

[0066] Example 12: Preparation of cyclopentanone and cyclopentanol by hydrogenation of furfural using carbon-coated cobalt catalyst

[0067] The preparation process and reaction conditions are the same as those in Example 3, except that the hydrogen pressure is 5 MPa.

[0068] Figure 1 , 2They are respectively the X-ray diffraction analysis diagram and infrared spectrum diagram of the carbon-coated cobalt catalyst at different pyrolysis temperatures in Examples 1-5. Figure 3 XRD analysis shows that when the pyrolysis temperature is lower than 500℃, the material still retains the crystal structure of MOF. When the pyrolysis temperature is higher than 500℃, a Co@C structure is formed. Among them, 2θ≈44.6, 52.1, 75.9 are Co0 crystal planes. Figure 4 Infrared analysis shows that when the temperature is below 500℃, the material still retains the functional groups of MOF, among which the peaks at 1460cm-1 and 1556cm-1 are attributed to -COO-, and 850 and 970 are the out-of-plane bending vibrations of the CH bond outside the benzene ring plane. Further Raman spectroscopy analysis found that 818cm-1 is attributed to the vibration of the CH bond, and 1281cm-1 is attributed to C=O.

[0069] From Table 1 and Figure 3 It can be seen that the conversion rate of furfural and the yield of different products, with the increase of pyrolysis temperature, the reducibility of Co is greatly improved, the conversion rate of furfural is also increased, and the product distribution has also changed. Among them, the transformation of the main product from cyclopentanone to cyclopentanol shows that even if the metal nanoparticles are coated, they still have a certain hydrogenation activity, but with the increase of pyrolysis temperature, Co nanoparticles cannot be encapsulated, and some oligomers are attached to the surface of the active site, resulting in a larger particle size. Therefore, the yield of cyclopentanol shows a trend of first increasing and then decreasing. At the same time, with the increase of reaction temperature, the yield of cyclopentanol shows a volcano-type change. At 140°C, some furfuryl alcohol and cyclopentanone are not converted, indicating that lower temperatures are not conducive to the rearrangement of the furan ring and the hydrogenation of C=O. Excessively high temperature will lead to instability of the intermediate, resulting in a decrease in carbon balance and an increase in the activity of side reactions, and the yield will also decrease accordingly. Therefore, when preparing carbon-coated cobalt catalysts, adjusting the appropriate pyrolysis reaction temperature is conducive to obtaining a stable cyclopentanol yield. From the change of hydrogen pressure during the reaction, it can be found that ( Figure 4 ), with the increase of hydrogen pressure, the yield of cyclopentanol did not increase significantly, while the content of tetrahydrofurfuryl alcohol and corrosive substances increased with the increase of pressure at the same temperature, indicating that the increase of hydrogen pressure will lead to the increase of side reaction activity, which is not conducive to the reaction.

[0070] In addition, a cyclic stability reaction test was carried out using the catalyst Co@C-500 and reaction conditions used in Example 3 to examine the stability of Co@C-500 under the optimal reaction conditions. The catalyst after the reaction was recovered, and after each reaction, the catalyst was separated by collecting the residual catalyst by centrifugal washing. The recovered catalyst was directly used in the next reaction, and then centrifuged and washed to collect. The catalyst was reused 5 times in total, and the yield of cyclopentanol remained basically unchanged, with the yield fluctuating around 92%. By comparing the results of 1 reaction with the results of 6 cycles of reactions, it can be seen that the catalyst particle size did not increase significantly, achieving the expected effect of high load, high dispersion and low particle size ( Figure 5 ), while the catalytic performance did not decrease ( Figure 6 ), maintaining a yield of cyclopentanol of about 90%, and has prospects for industrial application.

[0071] Table 1 Performance test data of carbon-coated cobalt catalyst for catalytic hydrogenation of furfural in aqueous phase in Examples 1-5

[0072]

[0073] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations of these embodiments are made without departing from the principles and spirit of the present invention, and still fall within the protection scope of the present invention.

Claims

1. A method for preparing a carbon-coated cobalt catalyst, characterized in that: The following steps are involved: S1. Dissolve the Co source in water, dissolve the organic ligand containing oxygen functional groups in an organic solvent, combine the two solutions, fully disperse them, and then perform a hydrothermal reaction to obtain a precursor of the Co-modified MOF material; S2. The precursor of S1 is dried and placed in a gas atmosphere for pyrolysis treatment to obtain a Co-modified MOF-derived Co@C catalyst material.

2. The method for preparing a carbon-coated cobalt catalyst according to claim 1, characterized in that: The Co source includes cobalt acetate, cobalt chloride, cobalt oxalate, cobalt carbonate, cobalt sulfate, and cobalt nitrate. The organic ligand containing oxygen functional groups is 2,5-dihydroxyterephthalic acid.

3. The method for preparing a carbon-coated cobalt catalyst according to claim 1, characterized in that: The organic solvent includes tetrahydrofuran and N,N-dimethylformamide.

4. The method for preparing a carbon-coated cobalt catalyst according to claim 1, characterized in that: The molar ratio of Co to organic ligand in the Co source is 0.5-2:

1.

5. The method for preparing a carbon-coated cobalt catalyst according to claim 1, characterized in that: The temperature of the hydrothermal reaction is 100-150° C. and the time is 24-96 hours.

6. The method for preparing a carbon-coated cobalt catalyst according to claim 1, characterized in that: The temperature of the pyrolysis treatment is 400-600°C, the time is 1-3h, and the heating rate is 4-6°C / min.

7. The method for preparing a carbon-coated cobalt catalyst according to claim 1, characterized in that: The gas atmosphere includes hydrogen atmosphere, argon atmosphere, and nitrogen atmosphere, and the gas flow rate is 40-60 mL / min.

8. A carbon-coated cobalt catalyst prepared by the preparation method according to any one of claims 1 to 7.

9. Use of the carbon-coated cobalt catalyst according to claim 8 in the aqueous phase hydrogenation reaction of furfural.

10. A method for preparing cyclopentanol by aqueous phase hydrogenation of furfural, characterized in that: Furfural, water and the carbon-coated cobalt catalyst according to claim 8 are added to a reaction kettle, and after replacing the air in the kettle, hydrogen is introduced to an initial pressure of 1-6 MPa, and then a catalytic selective hydrogenation reaction is carried out under stirring, wherein the ratio of furfural to catalyst is 3-5 mmol: 20-300 mg, the reaction temperature is 120-200°C, and the reaction time is 30-720 min.

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