Method for directionally regulating and controlling distribution of 5-hydroxymethylfurfural hydrogenation product by using activated carbon supported bimetallic catalyst

Abstract

The invention discloses a method for directionally regulating and controlling distribution of a 5-hydroxymethylfurfural hydrogenation product by using an activated carbon supported bimetallic catalyst, and belongs to the technical field of biomass catalytic conversion. According to the method, the activated carbon loaded bimetallic catalyst, the 5-hydroxymethylfurfural and the reaction solvent are mixed and then subjected to hydrogenation reaction, and directional regulation and control of distribution of the 5-hydroxymethylfurfural hydrogenation product are realized by controlling the reaction solvent to be a polar aprotic solvent or a polar protic solvent. The prepared activated carbon supported bimetallic catalyst can selectively catalyze 5-hydroxymethylfurfural in a polar aprotic solvent / protic solvent to synthesize a furan chemical with a high added value through hydrogenation, the 5-hydroxymethylfurfural can be efficiently catalyzed in a polar aprotic solvent system to synthesize 2, 5-furandimethanol, the selectivity can reach 97.1%, and the selectivity can reach 97.1%. And in a polar protic solvent system, hydrogenation synthesis of 2, 5-dimethylfuran from 5-hydroxymethylfurfural can be realized, and the selectivity is as high as 99.5%.

Description

Technical Field

[0001] The present invention belongs to the technical field of biomass catalytic conversion, and more specifically, relates to a method for directionally regulating the distribution of 5-hydroxymethylfurfural hydrogenation products by utilizing an activated carbon-supported bimetallic catalyst. Background Art

[0002] Numerous agricultural and forestry residues can be converted into renewable fuels and high-value-added chemicals through biorefining processes, which is a reliable way to achieve sustainable energy development. In biorefining, biomass-based platform compounds can be converted into various high-value-added chemicals, among which 5-hydroxymethylfurfural has attracted widespread attention from academia and industry. Because 5-hydroxymethylfurfural has multiple functional groups (aldehyde, hydroxymethyl, and furan ring), the catalytic conversion of 5-hydroxymethylfurfural is extremely challenging, requiring precisely designed catalysts to selectively activate each functional group.

[0003] 5-Hydroxymethylfurfural can be converted into a series of high-value-added furan chemicals through hydrogenation, such as 2,5-furan dimethanol, which is used as a pharmaceutical intermediate and synthetic polyester, 2,5-dihydroxymethyltetrahydrofuran, which is used to produce biopolymer monomers, 2,5-dimethylfuran as a second-generation liquid biofuel, and 1,6-hexanediol, an important precursor of bioplastics.

[0004] In the hydrogenation of 5-hydroxymethylfurfural, several metal oxides or hydroxides, metal-organic hybrids, molecular sieves, and zeolite catalysts have been widely used. However, these catalysts still have some inevitable disadvantages, such as the use of expensive precious metals, non-renewable raw materials, complex preparation methods, harsh reaction conditions, and low selectivity for the target product. High selectivity can even be achieved at the expense of activity. To address these issues, in catalyst preparation, the properties of the metal and the structure of the support have a significant impact on its catalytic performance. Therefore, the development of new catalyst systems is needed to break this "seesaw effect."

[0005] Furthermore, the activation and hydrogenation sequence of functional groups are crucial for catalyst design and active site regulation. Due to the complexity of the catalytic system, the mechanism of 5-HMF hydrogenation remains unclear, including the role of solvents and the structure-activity relationship of the actual reaction. Therefore, the preparation of highly active and selective catalysts for the selective hydrogenation of 5-HMF to synthesize high-value-added furanic chemicals is of great significance. Summary of the Invention

[0006] In view of the above problems existing in the prior art, the technical problems to be solved by the present invention are to provide a method for directionally regulating the hydrogenation product distribution of 5-hydroxymethylfurfural by using an activated carbon supported bimetallic catalyst, realizing the selective hydrogenation of 5-hydroxymethylfurfural in a polar aprotic solvent and a polar protic solvent system, and respectively obtaining highly selective 2,5-furandimethanol and 2,5-dimethylfuran. Another technical problem to be solved by the present invention is to provide a method for preparing an activated carbon supported bimetallic catalyst, using waste coconut shells as raw materials, introducing cheap and easily available non-precious metals as active components, with a green and stable preparation process and capable of uniformly dispersing the active components.

[0007] To solve the above technical problems, the technical solutions adopted by the present invention are as follows:

[0008] A method for directionally regulating the hydrogenation product distribution of 5-hydroxymethylfurfural by using an activated carbon supported bimetallic catalyst, mixing the activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural and a reaction solvent and then carrying out a hydrogenation reaction, and realizing the directional regulation of the hydrogenation product distribution of 5-hydroxymethylfurfural by controlling the reaction solvent to be a polar aprotic solvent or a polar protic solvent; the activated carbon supported bimetallic catalyst includes a coconut shell activated carbon carrier, a metal active component A and a metal active component B, the metal active component A is selected from any one of Ni, Co, and Cu, and the metal active component B is selected from any one of Zn and Al.

[0009] Preferably, the polar aprotic solvent is selected from any one of 1,4-dioxane, 2-methyltetrahydrofuran, tetrahydrofuran, and 1,3-dioxolane, and the polar protic solvent is selected from any one of methanol, ethanol, n-propanol, n-butanol, and isopropanol.

[0010] Preferably, in the hydrogenation reaction, the hydrogen pressure is 0.5 - 3 MPa, the reaction temperature is 150 - 170 °C, and the reaction time is 0.5 - 4 h.

[0011] Preferably, the mass ratio of the activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural and the reaction solvent is 1:2:16 - 26.

[0012] A method for preparing an activated carbon supported bimetallic catalyst, comprising the following steps:

[0013] 1) Using dry coconut shells as raw materials, performing thermal decomposition at high temperature with water vapor as the activation medium, the water vapor flow rate is 1 - 2.5 g / min, the heating rate is 5 - 10 °C / min, the activation temperature is 500 - 900 °C, the heat preservation time is 0.5 - 4 h, and after the activation is completed, obtaining coconut shell activated carbon through pickling, water washing and drying;

[0014] 2) Mix the coconut shell activated carbon obtained in step 1) with water to obtain an aqueous solution containing coconut shell activated carbon. After adding the mixed metal solution, adjust the pH value to 8.5 - 11, and then perform filtration, water washing, and drying treatments;

[0015] 3) Calcinate the product dried in step 2) in an air atmosphere, heat it to 500 - 800 °C at a heating rate of 1 - 5 °C / min and hold for 1 - 8 h. After the calcination is completed, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it to 300 - 500 °C at a heating rate of 1 - 5 °C / min and hold for 1 - 3 h to obtain the activated carbon supported bimetallic catalyst.

[0016] Preferably, in step 2), the mixed metal solution is composed of metal solution A and metal solution B. Metal solution A is selected from any one of Ni(NO3)2·6H2O, Co(NO3)2·6H2O, and Cu(NO3)2·6H2O, and metal solution B is selected from any one of Zn(NO3)2·6H2O and Al(NO3)3·9H2O.

[0017] Preferably, the concentration of metal solution A is 0.1 - 0.5 mol / L, and the concentration of metal solution B is 0.2 - 0.4 mol / L.

[0018] The activated carbon supported bimetallic catalyst prepared by the preparation method of the activated carbon supported bimetallic catalyst described above.

[0019] Application of the activated carbon supported bimetallic catalyst in the hydrogenation of 5-hydroxymethylfurfural to prepare highly selective 2,5-furandimethanol. Mix the activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural, and 1,4-dioxane, and place them in a reaction kettle. Perform a hydrogenation reaction under the conditions of a hydrogen pressure of 1 MPa, a reaction temperature of 160 °C, and a reaction time of 3 h to obtain 2,5-furandimethanol. The activated carbon supported bimetallic catalyst is selected from any one of the activated carbon supported nickel-zinc bimetallic catalyst, the activated carbon supported cobalt-zinc bimetallic catalyst, the activated carbon supported nickel-aluminum bimetallic catalyst, and the activated carbon supported cobalt-aluminum bimetallic catalyst.

[0020] Use of the activated carbon supported bimetallic catalyst in the hydrogenation of 5-hydroxymethylfurfural to prepare highly selective 2,5-dimethylfuran. The activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural and isopropanol are mixed and placed in a reaction kettle, and hydrogenation reaction is carried out under the conditions of hydrogen pressure of 1 MPa, reaction temperature of 160 °C and reaction time of 3 h to obtain 2,5-dimethylfuran. The activated carbon supported bimetallic catalyst is selected from any one of activated carbon supported nickel-zinc bimetallic catalyst, activated carbon supported cobalt-zinc bimetallic catalyst, activated carbon supported nickel-aluminum bimetallic catalyst, activated carbon supported copper-zinc bimetallic catalyst, activated carbon supported cobalt-aluminum bimetallic catalyst, and activated carbon supported copper-aluminum bimetallic catalyst.

[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0022] 1) The present invention uses waste coconut shells to prepare coconut shell activated carbon with high specific surface area and strong adsorption force by steam activation method. The raw materials are renewable, the preparation process is green, and the prepared coconut shell activated carbon has stable properties and is suitable as an adsorption material and catalyst carrier.

[0023] 2) The present invention prepares the activated carbon supported bimetallic catalyst by low-temperature co-precipitation, which can effectively slow down the rate of metal migration and aggregation during the preparation process, realize the uniform dispersion of metals on the surface of the carrier, and improve the metal utilization rate.

[0024] 3) The present invention uses the prepared activated carbon supported bimetallic catalyst to catalyze the efficient hydrogenation of 5-hydroxymethylfurfural. It can interact with the reaction solvent to jointly determine the selectivity of the 5-hydroxymethylfurfural hydrogenation product, and highly selective 2,5-furandimethanol and 2,5-dimethylfuran can be obtained in polar aprotic solvents and polar protic systems respectively. Description of the Drawings

[0025] Figure 1 Flow chart for preparing catalyst Ni-Zn / C in Example 1;

[0026] Figure 2 Nitrogen isothermal adsorption and desorption curve diagrams of the coconut shell activated carbon and catalyst Ni-Zn / C prepared in Example 1;

[0027] Figure 3 [[ID=I26]]X-ray diffraction pattern diagrams of the coconut shell activated carbon and catalyst Ni-Zn / C prepared in Example 1;

[0028] Figure 4 Transmission electron microscope image of the catalyst Ni-Zn / C prepared in Example 1;

[0029] Figure 5 X-ray photoelectron spectrum Ni 2p of the catalyst Ni-Zn / C prepared in Example 1 3 / 2Spectrum;

[0030] Figure 6 X-ray photoelectron spectrum of Zn 2p of the catalyst Ni-Zn / C prepared in Example 1 3 / 2 Spectrum;

[0031] Figure 7 Gas chromatogram-mass spectrum of the main products of 5-hydroxymethylfurfural hydrogenation catalyzed by the catalyst Ni-Zn / C prepared in Example 1;

[0032] Figure 8 Relationship diagram between the polarity of polar aprotic solvents and the selectivity of 2,5-furandimethanol in the 5-hydroxymethylfurfural hydrogenation reaction over the catalyst Ni-Zn / C prepared in Example 1;

[0033] Figure 9 Relationship diagram between the polarity of polar protic solvents and the selectivity of 2,5-dimethylfuran in the 5-hydroxymethylfurfural hydrogenation reaction over the catalyst Ni-Zn / C prepared in Example 1. Detailed implementation manners

[0034] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described below in conjunction with specific embodiments. In the following embodiments, unless otherwise specified, the technical means used are all conventional means well known to those skilled in the art. For those not specifying specific conditions in the embodiments, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments not indicating the manufacturer, they are all conventional products that can be obtained through commercial purchase.

[0035] Example 1

[0036] A preparation method of an activated carbon supported nickel-zinc bimetallic catalyst, as Figure 1 shown, includes the following steps:

[0037] (1) Select dry coconut shells with a particle size of 4-5.6 mm as raw materials and place them in a tubular furnace reactor. Using water vapor as the activation medium, the water vapor flow rate is 1.3 g / min, the heating rate is 10 °C / min, the activation temperature is 900 °C, and keep it warm for 1 h. After the activation, obtain coconut shell activated carbon through pickling, water washing and drying, denoted as C;

[0038] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment, mix 0.2 mol / L Ni(NO3)2·6H2O solution and 0.2 mol / L Zn(NO3)2·6H2O solution, and then add them dropwise to the aqueous solution containing coconut shell activated carbon with stirring. Then place it in a low-temperature reactor and slowly add 0.1 mol / L sodium hydroxide solution, stir and adjust the pH value of the suspension to 9.5 to generate metal hydroxide precipitate, and then filter, wash with water and dry;

[0039] (3) Calcinate the product dried in step (2) in an air atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination is completed, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 2 h to obtain an activated carbon supported nickel-zinc bimetallic catalyst, denoted as Ni-Zn / C.

[0040] It can be seen from Figure 2 that the isotherms of C and Ni-Zn / C both belong to the type I adsorption-desorption isotherm. The rapid increase in the adsorption amount in the low-pressure section indicates that both C and Ni-Zn / C prepared in Example 1 have a rich microporous structure and strong adsorption force.

[0041] It can be seen from Figure 3 that C does not have diffraction peaks, showing amorphous carbon, while Ni-Zn / C has typical diffraction peaks of metallic Ni (JCPDS, PDF#70-1849) and ZnO (JCPDS, PDF#79-2205), indicating that Ni and Zn have been successfully introduced onto C.

[0042] It can be seen from Figure 4 that the catalyst Ni-Zn / C prepared in Example 1 has lattice spacings of 0.124 and 0.137 nm on its surface, which belong to the lattice characteristics of Ni(220) and ZnO(112), and mostly show a state where ZnO semi-wraps metallic Ni and is uniformly dispersed on the carrier. At the same time, it can also be seen that the distributions of Ni and Zn elements are relatively consistent, indicating that the two have an interfacial effect and interaction.

[0043] It can be seen from Figure 5 that the three characteristic peaks in the figure respectively belong to the zero valence state of Ni bonded to the carrier or metallic Ni, the Ni 2+ [[ID=^24]]valence state of nickel oxide / hydroxynickel and the satellite peak. The coexistence of metal and oxide / hydroxide provides active sites for the activation and hydrogenation of the oxygen-containing functional groups of 5-hydroxymethylfurfural.

[0044] It can be seen from Figure 6 that there is only one characteristic peak at 1021.1 eV in the figure, which belongs to the Zn 2+ valence state of zinc oxide. The shift of the characteristic peaks of Ni2p 3 / 2 and Zn 2p 3 / 2 and the change in the binding energy cause charge rearrangement between Ni and Zn and have a synergistic effect.

[0045] Example 2

[0046] A preparation method of an activated carbon supported cobalt-zinc bimetallic catalyst, comprising the following steps:

[0047] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Using water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and holding for 1 h. After activation, obtain coconut shell activated carbon through pickling, washing, and drying;

[0048] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment. Mix 0.3 mol / L Co(NO3)2·6H2O solution and 0.3 mol / L Zn(NO3)2·6H2O solution, and then gradually add the mixture dropwise to the aqueous solution containing coconut shell activated carbon while stirring. Then place it in a low-temperature reactor and slowly add 0.1 mol / L sodium hydroxide solution. Stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitates, and then filter, wash, and dry;

[0049] (3) Calcinate the product dried in step (2) in an air atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After calcination, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it to 450 °C at a heating rate of 5 °C / min and hold for 3 h to obtain a nickel-zinc bimetallic catalyst supported on activated carbon, denoted as Co-Zn / C.

[0050] Example 3

[0051] A preparation method of a copper-zinc bimetallic catalyst supported on activated carbon, comprising the following steps:

[0052] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Using water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and holding for 1 h. After activation, obtain coconut shell activated carbon through pickling, washing, and drying;

[0053] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment. Mix 0.4 mol / L Cu(NO3)2·6H2O solution and 0.4 mol / L Zn(NO3)2·6H2O solution, and then gradually add the mixture dropwise to the aqueous solution containing coconut shell activated carbon while stirring. Then place it in a low-temperature reactor and slowly add 0.1 mol / L sodium hydroxide solution. Stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitates, and then filter, wash, and dry;

[0054] (3) Calcinate the product dried in step (2) in an air atmosphere, heat it up to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination is completed, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it up to 400 °C at a heating rate of 5 °C / min and hold for 1 h to obtain a copper-zinc bimetallic catalyst supported on activated carbon, denoted as Cu-Zn / C.

[0055] Example 4

[0056] A preparation method of a nickel-aluminum bimetallic catalyst supported on activated carbon, comprising the following steps:

[0057] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Use water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and hold for 1 h. After the activation is completed, obtain coconut shell activated carbon through pickling, washing, and drying.

[0058] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment. Mix a 0.2 mol / L Ni(NO3)2·6H2O solution and a 0.2 mol / L Al(NO3)3·9H2O solution, and then gradually add them dropwise to the aqueous solution containing coconut shell activated carbon with stirring. Then place it in a low-temperature reactor and slowly add a 0.1 mol / L sodium hydroxide solution, stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitates, and then filter, wash, and dry.

[0059] (3) Calcinate the product dried in step (2) in an air atmosphere, heat it up to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination is completed, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it up to 500 °C at a heating rate of 5 °C / min and hold for 2 h to obtain a nickel-aluminum bimetallic catalyst supported on activated carbon, denoted as Ni-Al / C.

[0060] Example 5

[0061] A preparation method of a cobalt-aluminum bimetallic catalyst supported on activated carbon, comprising the following steps:

[0062] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Use water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and hold for 1 h. After the activation is completed, obtain coconut shell activated carbon through pickling, washing, and drying.

[0063] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment. Mix 0.3 mol / L Co(NO3)2·6H2O solution and 0.3 mol / L Al(NO3)3·9H2O solution, and then slowly add the mixture drop by drop to the aqueous solution containing coconut shell activated carbon with stirring. Then place it in a low-temperature reactor and slowly add 0.1 mol / L sodium hydroxide solution. Stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitate. Subsequently, filter, wash with water and dry;

[0064] (3) Calcinate the product dried in step (2) in an air atmosphere. Heat it to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination is completed, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere. Heat it to 450 °C at a heating rate of 5 °C / min and hold for 3 h to obtain a cobalt-aluminum bimetallic catalyst supported on activated carbon, denoted as Co-Al / C.

[0065] Example 6

[0066] A preparation method of a copper-aluminum bimetallic catalyst supported on activated carbon, comprising the following steps:

[0067] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Use water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and hold for 1 h. After the activation is completed, obtain coconut shell activated carbon through pickling, washing with water and drying;

[0068] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment. Mix 0.4 mol / L Cu(NO3)2·6H2O solution and 0.4 mol / L Al(NO3)3·9H2O solution, and then slowly add the mixture drop by drop to the aqueous solution containing coconut shell activated carbon with stirring. Then place it in a low-temperature reactor and slowly add 0.1 mol / L sodium hydroxide solution. Stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitate. Subsequently, filter, wash with water and dry;

[0069] (3) Calcinate the product dried in step (2) in an air atmosphere. Heat it to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination is completed, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere. Heat it to 400 °C at a heating rate of 5 °C / min and hold for 1 h to obtain a copper-aluminum bimetallic catalyst supported on activated carbon, denoted as Cu-Al / C.

[0070] Comparative Example 1

[0071] A preparation method of a nickel monometallic catalyst supported on activated carbon, comprising the following steps:

[0072] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Using water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and holding for 1 h. After the activation, obtain coconut shell activated carbon through pickling, washing, and drying, denoted as C;

[0073] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment, and gradually add a 0.2 mol / L Ni(NO3)2·6H2O solution dropwise to the aqueous solution containing coconut shell activated carbon while stirring. Then place it in a low-temperature reactor and slowly add a 0.1 mol / L sodium hydroxide solution, stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitates, and then filter, wash, and dry;

[0074] (3) Calcinate the product dried in step (2) in an air atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 2 h to obtain a nickel-loaded single-metal catalyst on activated carbon, denoted as Ni / C.

[0075] Comparative Example 2

[0076] A preparation method of a zinc-loaded single-metal catalyst on activated carbon, comprising the following steps:

[0077] (1) Select dry coconut shells with a particle size of 4 - 5.6 mm as raw materials and place them in a tubular furnace reactor. Using water vapor as the activation medium, with a water vapor flow rate of 1.3 g / min, a heating rate of 10 °C / min, an activation temperature of 900 °C, and holding for 1 h. After the activation, obtain coconut shell activated carbon through pickling, washing, and drying, denoted as C;

[0078] (2) Disperse the coconut shell activated carbon obtained in step (1) in water for ultrasonic treatment, and gradually add a 0.2 mol / L Zn(NO3)2·6H2O solution dropwise to the aqueous solution containing coconut shell activated carbon while stirring. Then place it in a low-temperature reactor and slowly add a 0.1 mol / L sodium hydroxide solution, stir and adjust the pH value of the suspension to 9.5 to form metal hydroxide precipitates, and then filter, wash, and dry;

[0079] (3) Calcinate the product dried in step (2) in an air atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 5 h. After the calcination, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it to 500 °C at a heating rate of 5 °C / min and hold for 2 h to obtain a zinc-loaded single-metal catalyst on activated carbon, denoted as Zn / C.

[0080] Example 7

[0081] The catalysts prepared in Examples 1-6 and Comparative Examples 1-2, 5-hydroxymethylfurfural, and the reaction solvent were mixed at a mass ratio of 1:2:20 and placed in a sealed autoclave. Using hydrogen as the hydrogen source, a hydrogenation reaction was carried out under the conditions of a hydrogen pressure of 1 MPa, a reaction temperature of 160 °C, and a reaction time of 3 h to obtain the corresponding hydrogenation products.

[0082] 1. Using the above hydrogenation reaction process, the Ni-Zn / C catalyst obtained in Example 1 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents, and the results are shown in Tables 1-2.

[0083] Table 1 Results of Ni-Zn / C catalyzing the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents

[0084]

[0085] Table 2 Results of Ni-Zn / C catalyzing the hydrogenation of 5-hydroxymethylfurfural in different polar protic solvents

[0086]

[0087] As can be seen from Tables 1 and 2, Ni-Zn / C has the best catalytic performance in the polar aprotic solvent 1,4-dioxane and the polar protic solvent isopropanol system, and the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran can reach 97.9% and 99.5% respectively.

[0088] From Figure 7 it can be seen that the main products matching the gas chromatography-mass spectrometry diagram in the reaction system of polar aprotic solvents and polar protic solvents are 2,5-furandimethanol and 2,5-dimethylfuran.

[0089] From Figure 8 and Figure 9 it can be seen that in the hydrogenation reaction of 5-hydroxymethylfurfural, the solvent polarities (E T (30)) of polar aprotic solvents and polar protic solvents show a positive linear relationship with the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran respectively, because the higher the polarity of the solvent, the higher the solubility of the reaction substrate in the system, and thus the reaction is more complete.

[0090] 2. Using the above hydrogenation reaction process, the Co-Zn / C catalyst obtained in Example 2 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents, and the results are shown in Tables 3-4.

[0091] Table 3 Results of 5-hydroxymethylfurfural hydrogenation catalyzed by Co-Zn / C in different polar aprotic solvents

[0092]

[0093] Table 4 Results of 5-hydroxymethylfurfural hydrogenation catalyzed by Co-Zn / C in different polar protic solvents

[0094]

[0095] As can be seen from Table 3 and Table 4, Co-Zn / C has the best catalytic performance in the polar aprotic solvent 1,4-dioxane and the polar protic solvent isopropanol system, and the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran can reach 92.7% and 95.4% respectively.

[0096] 3. Using the above hydrogenation reaction process, the Cu-Zn / C catalyst obtained in Example 3 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents respectively, and the results are shown in Tables 5-6.

[0097] Table 5 Results of 5-hydroxymethylfurfural hydrogenation catalyzed by Cu-Zn / C in different polar aprotic solvents

[0098]

[0099] Table 6 Results of 5-hydroxymethylfurfural hydrogenation catalyzed by Cu-Zn / C in different polar protic solvents

[0100]

[0101] As can be seen from Table 5 and Table 6, Cu-Zn / C has the best catalytic performance in the polar aprotic solvent 1,4-dioxane and the polar protic solvent isopropanol system, and the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran can reach 88.8% and 94.1% respectively.

[0102] 4. Using the above hydrogenation reaction process, the Ni-Al / C catalyst obtained in Example 4 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents respectively, and the results are shown in Tables 7-8.

[0103] Table 7 Results of 5-hydroxymethylfurfural hydrogenation catalyzed by Ni-Al / C in different polar aprotic solvents

[0104]

[0105] Table 8 Results of 5-hydroxymethylfurfural hydrogenation catalyzed by Ni-Al / C in different polar protic solvents

[0106]

[0107]

[0108] As can be seen from Tables 7 and 8, Ni-Al / C has the optimal catalytic performance in the polar aprotic solvent 1,4-dioxane and the polar protic solvent isopropanol system, and the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran can reach 94.2% and 91.3% respectively.

[0109] 5. Using the above hydrogenation reaction process, the Co-Al / C catalyst obtained in Example 5 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents respectively, and the results are shown in Tables 9-10.

[0110] Table 9 Results of Co-Al / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Aprotic Solvents

[0111]

[0112] Table 10 Results of Co-Al / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Protic Solvents

[0113]

[0114] As can be seen from Tables 9 and 10, Co-Al / C has the optimal catalytic performance in the polar aprotic solvent 1,4-dioxane and the polar protic solvent isopropanol system, and the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran can reach 90.4% and 90.6% respectively.

[0115] 6. Using the above hydrogenation reaction process, the Cu-Al / C catalyst obtained in Example 6 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents respectively, and the results are shown in Tables 11-12.

[0116] Table 11 Results of Cu-Al / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Aprotic Solvents

[0117]

[0118] Table 12 Results of Cu-Al / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Protic Solvents

[0119]

[0120] As can be seen from Table 11 and Table 12, Cu-Al / C has the optimal catalytic performance in the polar aprotic solvent 1,4-dioxane and the polar protic solvent isopropanol system, and the selectivities of 2,5-furandimethanol and 2,5-dimethylfuran can reach 88.9% and 92.1% respectively.

[0121] 7. Using the above hydrogenation reaction process, the Ni / C catalyst obtained in Comparative Example 1 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents respectively, and the results are shown in Tables 13-14.

[0122] Table 13 Results of Ni / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Aprotic Solvents

[0123]

[0124]

[0125] Table 14 Results of Ni / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Protic Solvents

[0126]

[0127] As can be seen from Table 13 and Table 14, the highest conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-furandimethanol in the polar aprotic solvent system catalyzed by Ni / C are only 56.9% and 77.3% respectively, while in the polar protic solvent system, the highest conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-dimethylfuran are only 73.7% and 91.2% respectively.

[0128] 8. Using the above hydrogenation reaction process, the Zn / C catalyst obtained in Comparative Example 2 was used to catalyze the hydrogenation of 5-hydroxymethylfurfural in different polar aprotic solvents and polar protic solvents respectively, and the results are shown in Tables 15-16.

[0129] Table 15 Results of Zn / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Aprotic Solvents

[0130]

[0131] Table 16 Results of Zn / C Catalyzing the Hydrogenation of 5-Hydroxymethylfurfural in Different Polar Protic Solvents

[0132]

[0133]

[0134] As can be seen from Table 15 and Table 16, the highest conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-furandimethanol in the polar aprotic solvent system with Zn / C are only 36.4% and 53.1% respectively, while in the polar protic solvent system, the highest conversion rate of 5-hydroxymethylfurfural and the selectivity of 2,5-dimethylfuran are only 52.7% and 56.9% respectively.

[0135] From the results of the hydrogenation of 5-hydroxymethylfurfural catalyzed by the catalysts in Examples 1-6 and Comparative Examples 1-2, it can be seen that the activated carbon supported single-metal catalyst does not have obvious catalytic advantages in the hydrogenation reaction of 5-hydroxymethylfurfural. However, after loading two metals on the activated carbon, the two metals can produce a synergistic effect in the hydrogenation reaction, adjusting the electron density of the metal and thus promoting hydrogenation reactions to different extents.

[0136] Example 8

[0137] The catalysts prepared in Examples 1-6 were filtered after the reaction, washed three times with ethanol and deionized water respectively, and dried at 80 °C for 12 h and then recycled. The results are shown in Table 17.

[0138] Table 17 Results of cyclic stability test

[0139]

[0140] As can be seen from Table 17, the catalyst still has good catalytic activity after 5 cycles of use (the conversion rate and selectivity decrease by about 5%), and among them, Ni-Zn / C has the best catalytic performance and stability.

[0141] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for directionally regulating the product distribution of 5-hydroxymethylfurfural hydrogenation by using an activated carbon-supported bimetallic catalyst, characterized in that, Mix an activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural and a reaction solvent, and then carry out a hydrogenation reaction. By controlling the reaction solvent to be a polar aprotic solvent or a polar protic solvent, the directional regulation of the hydrogenation product distribution of 5-hydroxymethylfurfural is realized; the activated carbon supported bimetallic catalyst includes a coconut shell activated carbon carrier, a metal active component A and a metal active component B. The metal active component A is selected from any one of Ni, Co, and Cu, and the metal active component B is selected from any one of Zn and Al.

2. The method for directionally regulating the product distribution of 5-hydroxymethylfurfural hydrogenation by using an activated carbon supported bimetallic catalyst according to claim 1, wherein, The polar aprotic solvent is selected from any one of 1,4-dioxane, 2-methyltetrahydrofuran, tetrahydrofuran, and 1,3-dioxolane, and the polar protic solvent is selected from any one of methanol, ethanol, n-propanol, n-butanol, and isopropanol.

3. The method for directionally regulating the product distribution of 5-hydroxymethylfurfural hydrogenation by using an activated carbon supported bimetallic catalyst according to claim 1, wherein, In the hydrogenation reaction, the hydrogen pressure is 0.5 - 3 MPa, the reaction temperature is 150 - 170 °C, and the reaction time is 0.5 - 4 h.

4. The method for directionally regulating the product distribution of 5-hydroxymethylfurfural hydrogenation by using an activated carbon supported bimetallic catalyst according to claim 1, wherein, The mass ratio of the activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural, and the reaction solvent is 1:2:16 - 26.

5. A method for preparing the activated carbon-supported bimetallic catalyst according to claim 1, characterized in that, It includes the following steps: 1) Using dry coconut shell as the raw material, perform thermal decomposition at high temperature using water vapor as the activation medium. The water vapor flow rate is 1 - 2.5 g / min, the heating rate is 5 - 10 °C / min, the activation temperature is 500 - 900 °C, the heat preservation time is 0.5 - 4 h. After the activation, obtain coconut shell activated carbon through pickling, water washing, and drying. 2) Mix the coconut shell activated carbon obtained in step 1) with water to obtain an aqueous solution containing coconut shell activated carbon. After adding a mixed metal solution, adjust the pH value to 8.5 - 11, and perform filtration, water washing, and drying treatments. 3) Calcinate the product dried in step 2) in an air atmosphere, heat it to 500 - 800 °C at a heating rate of 1 - 5 °C / min and keep it warm for 1 - 8 h. After the calcination, reduce the calcined product in a hydrogen-nitrogen mixed gas atmosphere, heat it to 300 - 500 °C at a heating rate of 1 - 5 °C / min and keep it warm for 1 - 3 h to obtain the activated carbon supported bimetallic catalyst.

6. The preparation method of the activated carbon supported bimetallic catalyst according to claim 5, characterized in that, In step 2), the mixed metal solution consists of metal solution A and metal solution B. Metal solution A is selected from any one of Ni(NO3)2·6H2O, Co(NO3)2·6H2O, and Cu(NO3)2·6H2O, and metal solution B is selected from any one of Zn(NO3)2·6H2O and Al(NO3)3·9H2O.

7. The preparation method of the activated carbon supported bimetallic catalyst according to claim 6, characterized in that, The concentration of the metal solution A is 0.1 - 0.5 mol / L, and the concentration of the metal solution B is 0.2 - 0.4 mol / L. The activated carbon supported bimetallic catalyst prepared by the preparation method of the activated carbon supported bimetallic catalyst according to any one of claims 5 - 7.

9. Use of the activated carbon supported bimetallic catalyst according to claim 8 in the hydrogenation of 5-hydroxymethylfurfural to prepare highly selective 2,5-furandimethanol, characterized in that, Mix the activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural, and 1,4-dioxane, and then place them in a reaction kettle. Carry out a hydrogenation reaction under the conditions of a hydrogen pressure of 1 MPa, a reaction temperature of 160 °C, and a reaction time of 3 h to obtain 2,5-furandimethanol. The activated carbon supported bimetallic catalyst is selected from any one of an activated carbon supported nickel-zinc bimetallic catalyst, an activated carbon supported cobalt-zinc bimetallic catalyst, an activated carbon supported nickel-aluminum bimetallic catalyst, and an activated carbon supported cobalt-aluminum bimetallic catalyst.

10. Use of the activated carbon supported bimetallic catalyst according to claim 8 in the hydrogenation of 5-hydroxymethylfurfural to prepare highly selective 2,5-dimethylfuran, characterized in that, The activated carbon supported bimetallic catalyst, 5-hydroxymethylfurfural, and isopropanol are mixed and placed in a reaction kettle, and a hydrogenation reaction is carried out under the conditions of a hydrogen pressure of 1 MPa, a reaction temperature of 160 °C, and a reaction time of 3 h to obtain 2,5-dimethylfuran; The activated carbon supported bimetallic catalyst is selected from any one of an activated carbon supported nickel-zinc bimetallic catalyst, an activated carbon supported cobalt-zinc bimetallic catalyst, an activated carbon supported nickel-aluminum bimetallic catalyst, an activated carbon supported copper-zinc bimetallic catalyst, an activated carbon supported cobalt-aluminum bimetallic catalyst, and an activated carbon supported copper-aluminum bimetallic catalyst.

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