Preparation method and application of phenolic compound hydrodeoxygenation catalyst

Abstract

The invention discloses a preparation method and application of a phenolic compound hydrodeoxygenation catalyst. The preparation method comprises the following steps: firstly, by taking commercial Ga2O3 as a raw material, uniformly adsorbing and dispersing cobalt nitrate and nickel nitrate on the surface of Ga2O3 through a dipping adsorption method; and then roasting at high temperature in a muffle furnace in an air atmosphere, and roasting and reducing in a tubular furnace in a hydrogen atmosphere to prepare the CoNi / Ga2O3 catalyst. In the hydrodeoxygenation reaction of the phenolic compound, the CoNi / Ga2O3 catalyst, the phenolic compound and isopropanol are added into a high-pressure reaction kettle, 1.0-3.0 MPa H2 is introduced, the reaction is performed for 1-6 hours at 120-180 DEG C, the conversion rate of the phenolic compound is as high as 99%, the selectivity of alcohol is as high as 95%, and the catalyst can be used for five times and still keeps activity. According to the method, the preparation method of the CoNi / Ga2O3 catalyst is simple, the active site Co is doped into Ga2O3 crystal lattices, Ni is loaded on the surface of Ga2O3 in a nano-particle mode, high catalytic activity and stability can be kept in the phenol compound hydrodeoxygenation reaction, and the CoNi / Ga2O3 catalyst is easy to industrially produce and convert.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of fine chemical technology, in particular to a preparation method of a catalyst for hydrogenation and deoxygenation of phenolic compounds, and application of the catalyst in catalyzing synthesis of alcohol compounds from phenolic compounds. BACKGROUND

[0002] Cyclohexanol is an important alicyclic alcohol organic chemical intermediate, which is a colorless transparent oily liquid at room temperature and has a camphor-like odor. It is the main raw material for producing adipic acid and caprolactam, which are the key precursors of nylon 6 and nylon 66. At present, the industrial production routes of cyclohexanol mainly include cyclohexane oxidation method, phenol hydrogenation method and cyclohexene hydration method, all of which are heavily dependent on non-renewable fossil resources (ACS Catal., 9(4), (2019), 3551-3563). Guaiacol, as an important biomass-derived platform compound, has attracted widespread attention. It can be obtained efficiently through directional depolymerization of lignin or biotransformation, and is abundant in source and renewable. From the molecular structure, guaiacol has both methoxy (-OCH3) and hydroxyl (-OH) functional groups on the benzene ring, which makes it one of the ideal model compounds for preparing various deoxygenated products through catalytic conversion (J. Am. Chem. Soc., 144(45), (2022), 20834-20846). In theory, guaiacol can be saturated and deoxygenated through selective hydrogenation and deoxygenation reaction path, and finally converted into cyclohexanol.

[0003] Although there have been a large number of studies on the hydrodeoxygenation of guaiacol, the complex product mixture and the difficulty of controlling selectivity still exist. Although noble metal catalysts exhibit excellent catalytic performance, their high cost limits their practical application. While nickel-based catalysts are low in cost, high in hydrogenation activity, and have strong resistance to sintering, they have great potential in the conversion of lignin derivatives (ACS Catal., 12(24), (2022), 15181-15192). For example, Ni / HZSM-5 and Ni / SiO2 systems have been used for the hydrodeoxygenation of guaiacol and phenol. Studies have also shown that although acidic supports are beneficial for the cleavage of C-O bonds, they often lead to severe carbon deposition and instability of the catalyst (Green Chem., 17(2), (2015), 1204-1218). In addition, single-metal nickel-based catalysts often require more severe reaction conditions (e.g., temperatures higher than 200°C and pressures of 3 MPa) to achieve effective conversion. In order to achieve effective conversion under milder conditions, a second metal (such as Fe, Co, W, Mo, and Re) is introduced to regulate the electronic structure of nickel. At the same time, the formation of alloy centers promotes the dissociation of hydrogen, which is an effective performance regulation strategy. For example, in the CoRe 0.1 / TiO2-Vo system, the introduction of Re regulates the electronic structure and acidity of the catalyst, and also enhances the selectivity of C-O bond cleavage (Chem. Eng. J., 522, (2025), 167155). In addition, the bimetallic system can significantly promote the hydrogen spillover effect, making the active hydrogen migrate from the metal sites to the support or other active sites, thereby improving the reaction activity and selectivity. For example, the introduction of Fe species in the Pt / Fe-TiO2 system has been shown to significantly enhance hydrogen spillover (ACS Catal., 14(7), (2024), 4478-4488). However, current research on enhancing hydrogen spillover on non-reducible supports (such as Al2O3, SiO2, and Ga2O3) is still relatively limited.

[0004] Ga2O3 has the ability to form gallium-hydrogen (Ga-H) on its surface, which has attracted widespread attention. Researchers have used advanced solid-state nuclear magnetic resonance techniques to directly observe these Ga2O3 surface Ga-H species and confirmed their activity in CO2 hydrogenation (J. Am. Chem. Soc., 144(38), (2022), 17365-17375). However, the migration ability of Ga-H is limited, and the proton-electron coupling migration mechanism is inefficient, resulting in weaker hydrogen overflow ability than TiO2 and other reducible carriers. Therefore, improving the hydrogen overflow efficiency of Ga2O3 is a key challenge in current research. Selecting the non-reducible carrier Ga2O3 as a research model is crucial for elucidating and enhancing the intrinsic overflow mechanism of hydrogen, as it eliminates the complex interference brought by the change of valence state in the hydrogen migration process. This method can more accurately study the basic scientific problems of proton-electron coupling migration in the carrier. SUMMARY

[0005] To solve the above problems, the present application provides a preparation method of a nickel-loaded, cobalt-doped Ga2O3 catalyst; the catalyst CoNi / Ga2O3 prepared from the non-reducible carrier Ga2O3 has the ability to overflow hydrogen; and using the prepared catalyst, a method for catalytically synthesizing alcohol compounds from phenolic compounds is provided (taking the hydrogenation deoxidation of guaiacol as an example, see the formula below).

[0006]

[0007] To solve the technical problems of the present application, the following technical solutions are adopted:

[0008] A preparation method of a phenolic compound hydrogenation deoxidation catalyst and its application, the preparation method of the CoNi / Ga2O3 catalyst is as follows: first, using cobalt nitrate hexahydrate, nickel nitrate hexahydrate and gallium oxide as raw materials, adding an appropriate amount of deionized water; then, stirring at 50℃ for 12h to make it fully mixed and uniform, then increasing the temperature to 95℃ to evaporate the solvent, grinding to obtain a solid powder; then, the prepared powder is placed in a muffle furnace and programmed to 200-400℃, high-temperature calcination in air for 2-4h, and high-temperature reduction in H2 atmosphere for 2-3h, and then argon is passed for 30 minutes after the temperature is lowered to room temperature, to obtain the CoNi / Ga2O3 catalyst.

[0009] The precursor material used in the preparation of the CoNi / Ga2O3 catalyst is commercial Ga2O3, which is calcined at 800℃ in a muffle furnace for 5h, has a rich mesoporous structure, can adsorb Co 2+ , Ni 2+ , and further obtain Co δ+ Ni δ+ / Ga2O3 precursor material.

[0010] The CoNi / Ga2O3 catalyst preparation method uses cobalt nitrate hexahydrate, nickel nitrate hexahydrate and Ga2O3 as precursor materials, which are uniformly dispersed by impregnation method, and then the CoNi / Ga2O3 catalyst doped with cobalt and loaded with nickel is obtained after high-temperature calcination and hydrogen reduction. The specific surface area of the Ga2O3 carrier is 5.7 m 2 -1 g, and the average pore size is 24 nm.

[0011] In the CoNi / Ga2O3 catalyst preparation method, the calcination temperature in air atmosphere is 200-400℃, the calcination temperature in reducing atmosphere is 200-500℃, the reducing atmosphere is hydrogen, the reducing gas flow rate is 20 mL / min, and the heating rate is 2-10℃ / min.

[0012] In the CoNi / Ga2O3 catalyst preparation method, Co is doped into the crystal lattice of gallium oxide, and Ni nanoparticles are loaded on the mesoporous surface of gallium oxide, effectively preventing the loss of Co and Ni active sites.

[0013] The mass ratio of metal to carrier in the prepared CoNi / Ga2O3 catalyst is Co: Ni: Ga2O3 = 0.1-0.05: 0.05-0.1: 1.

[0014] The CoNi / Ga2O3 catalyst is applied in the phenolic hydrodeoxygenation reaction, and the specific method is as follows: a certain amount of CoNi / Ga2O3 catalyst, guaiacol and isopropyl alcohol are added to a high-pressure reaction kettle, replaced with hydrogen three times, then hydrogen gas with a predetermined pressure is filled into the high-pressure reaction kettle, the reactor temperature is set, and the reaction progress is analyzed by gas chromatograph. The conversion rate of guaiacol is as high as 99.9%, and the yield of cyclohexanol is as high as 95.1%.

[0015] The gas pressure of the phenolic hydrodeoxygenation reaction is 1.0-3.0 MPa, the reaction temperature is 120-180℃, and the reaction time is 1-6 hours.

[0016] In the phenolic hydrodeoxygenation reaction, the CoNi / Ga2O3 catalyst can be used for 5 times, and still maintains stable catalytic activity.

[0017] ​Advantages of this invention: 1. The CoNi / Ga2O3 catalyst designed and prepared in this invention, which is Co-doped and Ni-supported on Ga2O3, is mainly prepared using a simple impregnation adsorption method and a calcination reduction method. The catalyst preparation method is simple, the conditions are mild, and the catalyst is easy to scale up for production. 2. In the CoNi / Ga2O3 catalyst, Co is doped into the Ga2O3 lattice, and ultrafine Ni nanoparticles are uniformly dispersed and supported in mesoporous Ga2O3. This achieves hydrogen overflow capability on the non-reducing support Ga2O3, providing a new perspective for exploring hydrogen overflow on non-reducing supports. Furthermore, the catalyst exhibits excellent stability, maintaining high activity even after five reuses. 3. The CoNi / Ga2O3 catalyst provided in this invention exhibits high phenol conversion rate and high alcohol yield in the catalytic hydrodeoxygenation reaction of phenols. The reaction operation is simple and easy to control, making it easy for industrial application and scale-up production. Attached Figure Description

[0018] Figure 1 Transmission electron microscopy (TEM) images of the Ga2O3 support (a) and CoNi / Ga2O3 catalyst (b) prepared in Example 1 of this invention.

[0019] Figure 2 This is a diagram illustrating the effect of catalyst reuse in the CoNi / Ga2O3 catalyst catalyzing the hydrodeoxygenation reaction of guaiacol in Example 1 of this invention. Detailed Implementation

[0020] Example 1

[0021] A method for preparing a phenolic compound hydrodeoxygenation catalyst and its application are disclosed. The specific operation method is as follows: 2g of commercial Ga2O3 is calcined in a muffle furnace at 800℃ for 5h to obtain β-isomer Ga2O3. 0.25g of nickel nitrate hexahydrate, 0.25g of cobalt nitrate hexahydrate, 0.9g of Ga2O3, and 20mL of deionized water are added to a round-bottom flask, dissolved uniformly, and stirred continuously at 50℃ for 12h. The solvent is then evaporated at 95℃. The solid powder is then dried in a drying oven at 100℃ for 12h. The resulting solid powder is then placed in a muffle furnace and heated to 300℃ at a rate of 5℃ / min, calcined in air for 3h, and then reduced in a tube furnace at 300℃ for 2h in H2 atmosphere to obtain a CoNi / Ga2O3 catalyst with a Co and Ni content of 5.0%-10.0%.

[0022] Example 2

[0023] A method for preparing a phenolic compound hydrodeoxygenation catalyst and its application are disclosed. The specific method is as follows: 75 mg of the Co5Ni5 / Ga2O3 catalyst from Example 1, 1 mmol of guaiacol, and 10 mL of isopropanol were added to a 50 mL high-pressure reactor. H2 was introduced at 1.2 MPa, and the reaction was carried out at 180 °C for 6 h. After the reaction, the high-pressure reactor was cooled to room temperature with ice water. The gas chromatography-mass spectrometry (GC-MS) analysis showed that the conversion rate of guaiacol was 99.9%, and the selectivity of cyclohexanol was 95.2%.

[0024] Example 3-11

[0025] A method for preparing a phenolic compound hydrodeoxygenation catalyst and its application are disclosed. The specific method is as follows: Following the method in Example 2, 75 mg of the Co5Ni5 / Ga2O3 catalyst from Example 1, 1 mmol of the phenolic compound, and 10 mL of isopropanol were added to a 50 mL high-pressure reactor, and H2 at 1.2 MPa was introduced. The reaction was carried out at 180 °C. The conversion rate of the phenolic compound and the selectivity of the product alcohol were analyzed by gas chromatography-mass spectrometry (GC-MS). The results are shown in Table 1.

[0026] Table 1. Results of Co5Ni5 / Ga2O3 catalyzed reactions of different phenolic compounds.

[0027]

[0028] Example 12

[0029] A method for preparing a phenolic compound hydrodeoxygenation catalyst and its application are disclosed. The specific method is as follows: After filtration and washing, the Co5Ni5 / Ga2O3 catalyst from Example 2 is added to a 50mL high-pressure reactor along with 1mmol of guaiacol and 10mL of isopropanol. H2 is introduced at 1.2MPa, and the reaction is carried out at 180℃ for 6h. The results were analyzed by gas chromatography-mass spectrometry (GC-MS). The conversion rate of guaiacol was higher than 91.2% and the yield of cyclohexanol was higher than 80% after five reuses of the Co5Ni5 / Ga2O3 catalyst. The content of active metals was detected by ICP. The Co and Ni components were almost not lost.

Claims

1. A method for preparing a phenolic compound hydrodeoxygenation catalyst and its application, characterized in that: First, commercial Ga2O3 was calcined in a muffle furnace at 800℃ for 5 hours. Then, using cobalt nitrate hexahydrate and nickel nitrate hexahydrate as raw materials, powder materials were obtained by impregnation adsorption. Subsequently, the catalyst CoNi / Ga2O3 was prepared by high-temperature calcination in air atmosphere and calcination reduction in hydrogen atmosphere.

2. The preparation method of the phenolic compound hydrodeoxygenation catalyst according to claim 1 and its application, characterized in that: The CoNi / Ga2O3 catalyst was prepared by impregnation adsorption method. After high-temperature calcination and hydrogen reduction, Co was doped into the Ga2O3 lattice, while Ni existed on the surface of Ga2O3 in the form of nanoclusters.

3. The preparation method of the phenolic compound hydrodeoxygenation catalyst according to claim 1 and its application, characterized in that: Cobalt and nickel nitrate precursors were loaded onto Ga₂O₃ using an impregnation method, followed by high-temperature calcination and hydrogen reduction; the specific surface area of ​​CoNi / Ga₂O₃ was 4.2-10.8 m². 2 ·g -1 The average pore size is 24 nm.

4. The preparation method of the phenolic compound hydrodeoxygenation catalyst according to claim 1 and its application, characterized in that: In the preparation method of the CoNi / Ga2O3 catalyst, the calcination temperature in air atmosphere is 200-400℃, the calcination temperature in reducing atmosphere is 200-500℃, the reducing atmosphere is pure hydrogen, the reducing gas flow rate is 20mL / min, and the heating rate is 2-10℃ / min.

5. The preparation method of the phenolic compound hydrodeoxygenation catalyst according to claim 1 and its application, characterized in that: In the CoNi / Ga2O3 catalyst preparation method, Ni nanoparticles are dispersed on the surface of Ga2O3, while Co is doped into the Ga2O3 lattice. This strategy enables the catalyst prepared from the non-reducible Ga2O3 support to have hydrogen overflow capability. The mass ratio of active metal to support in the CoNi / Ga2O3 catalyst is Co:Ni:Ga2O3 = 0.05-0.1:0.05-0.1:

1.

6. The preparation method of the phenolic compound hydrodeoxygenation catalyst according to claim 1 and its application, characterized in that: The CoNi / Ga2O3 catalyst was applied to the hydrodeoxygenation reaction of guaiacol. The CoNi / Ga2O3 catalyst, guaiacol, and isopropanol were added to a high-pressure reactor, and hydrogen gas of 1.0-3.0 MPa was introduced. The reaction was carried out at 120-180℃ for 1-6 hours. The conversion rate of guaiacol was as high as 99.9%, and the selectivity of cyclohexanol was as high as 95.2%.

7. The preparation method of a phenolic compound hydrodeoxygenation catalyst according to claims 1 and 6 and its application, characterized in that: The CoNi / Ga2O3 catalyst was applied to the hydrodeoxygenation reaction of guaiacol to evaluate the reusability and stability of the catalyst. The catalyst can be reused 5 times and still maintains high catalytic activity. The conversion rate of guaiacol is higher than 91.2% and the yield of cyclohexanol is higher than 80%.

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