High-activity catalyst for preparing 2-methylfuran from furfural through hydrodeoxygenation and preparation method thereof

Abstract

The application discloses a high-activity catalyst for preparing 2-methyl furan through furfural hydrodeoxygenation and a preparation method thereof. The catalyst is a porous biochar loaded with Ni and Mo bimetal, and has a chemical formula of aNi-bMoOx / C. a is the mass percentage of Ni in the carrier, a=0.6-1%, b is the mass percentage of Mo in the carrier, b=0.12-0.2%, x is the number of O, x=2-3, and the molar ratio of the metal nickel and molybdenum is 7-14:1. The prepared catalyst can be used for preparing 2-methyl furan through a direct furfural hydrodeoxygenation reaction. The metal content is at most 1.2% of the non-metal carrier, the cost of the catalyst is reduced, the furfural hydrodeoxygenation reaction activity and the selectivity of 2-methyl furan are significantly improved, the molar ratio of the metal nickel and furfural is 1:30, the reaction condition is 200 DEG C, the reaction is at most 4 hours, the highest furfural conversion rate is 99.9%, and the best 2-methyl furan selectivity is 92.5%.

Description

Technical Field

[0001] This invention belongs to the field of heterogeneous catalysis, and particularly relates to a highly active catalyst for the hydrogenation and deoxygenation of furfural to 2-methylfuran and its preparation method. Background Technology

[0002] Furan compounds, as important organic intermediates, have wide applications in dyes, pharmaceuticals, and fuel additives. In the direct hydrodeoxygenation process using furfural as a substrate, the aldehyde carbonyl group in the furfural molecule is first adsorbed onto the catalyst surface in a tilted adsorption configuration. Through hydrogen activation by the catalyst, it is converted into the intermediate furfuryl alcohol, and then loses a water molecule (H₂O), achieving hydrogenolysis of the CO bond and ultimately converting into 2-methylfuran. Previously, noble metal-based catalysts have shown high activity in furfural hydrodeoxygenation reaction systems. For example, Sakthivel Kumaravel et al. prepared a series of Ru catalysts with different Ru / Ni ratios using an in-situ hydrothermal synthesis method. x / Ni y The / SBA-16 catalyst was applied to the hydrogenolysis process of furfural hydrodeoxygenation to 2-methylfuran. This catalyst exhibited good catalytic performance under mild reaction conditions, achieving 100% conversion of furfural and 88% selectivity for 2-methylfuran (Materials Chemistry and Physics 316(2024)129083). However, the high cost of the precious metal ruthenium hinders its large-scale application. Therefore, efforts are being made to develop more economical non-precious metal heterogeneous catalysts.

[0003] Wang et al. developed a bimetallic Ni-Cu alloy catalyst supported on ZSM-5 zeolite catalyst using a wet impregnation method and used it for the hydrodeoxygenation of furfural to produce 2-methylfuran. However, when the furfural conversion rate was 100%, the yield of 2-methylfuran could only reach 78.8% (Fuel 353(2023)129233).

[0004] Chinese invention patent application CN 112264032 B discloses a catalyst for the catalytic hydrogenation deoxygenation of furfural to prepare 2-methylfuran. The catalyst is composed of Ni, Mo, and ZrO2 support, with a molar ratio of Ni, Mo, and ZrO2 support of 0.1-0.4:0.1-0.4:1. When the mass ratio of NiMo / ZrO2 catalyst to furfural as the reactant is 0.1:1, the reaction temperature is 180℃, the hydrogen pressure is 3MPa, and the catalytic hydrogenation deoxygenation reaction of furfural is carried out for 6 hours, the crude 2-methylfuran product is obtained with a molar yield of 94%.

[0005] Chinese invention patent CN 113304756 B discloses "A Ni-Mo bimetallic alloy catalyst and its preparation method and application." This catalyst involves embedding a small number of Ni atoms into the MoO2 lattice to form an alloy, preventing Ni agglomeration during high-temperature calcination. Furthermore, due to the sufficient contact between Ni and Mo, electron transfer occurs at high temperatures, with the electrons shifting from Mo to Ni, increasing the electron density on the Ni surface. This improves the yield of 2-methylfuran under the influence of metal particle size and electronic effects. The synergistic effect of the Ni-Mo bimetallic alloy influences the size and electronic structure of metal nanoparticles, thereby enhancing the catalytic performance for the hydrodeoxygenation of furfural to 2-methylfuran. The specific production method involves ball milling a mixture of acetylacetone, nickel, and molybdenum acetylacetone, adding an organic solvent for further ball milling, drying, and calcining to obtain a composite oxide. The oxide is then pulverized and reduced in a tube furnace under a hydrogen atmosphere to obtain the bimetallic alloy catalyst for the hydrodeoxygenation of furfural to 2-methylfuran. Using 5g isopropanol and 0.3g furfural as raw materials, and employing 0.05g Ni-Mo bimetallic alloy catalyst, a catalytic reaction was carried out at 190℃. The furfural conversion rate was measured to be 80.0%, and the 2-methylfuran selectivity was 78.1%. Under the conditions of 200℃ and 1.0MPa for 7 hours, the furfural conversion rate was 100%, and the 2-methylfuran selectivity was 92.2%.

[0006] It is evident that existing technologies already employ catalysts with metallic Ni and Mo as active components. However, due to differences in preparation methods and product composition, these catalysts exhibit varying catalytic effects when applied to the hydrodeoxygenation of furfural to 2-methylfuran. A common problem is the high metal content in the catalysts, resulting in long reaction times, high costs, and low efficiency in the hydrodeoxygenation of furfural to 2-methylfuran. Summary of the Invention

[0007] The present invention aims to solve the above-mentioned technical problems existing in the prior art by providing a highly active catalyst for the hydrogenation and deoxygenation of furfural to 2-methylfuran and a preparation method thereof.

[0008] The technical solution of this invention is: a highly active catalyst for the hydrogenation and deoxygenation of furfural to produce 2-methylfuran, characterized in that: a Ni-Mo bimetallic compound is supported on porous biochar, with the chemical formula aNi-bMoOx / C, where a is the mass percentage of Ni to the support, a = 0.6-1%, b is the mass percentage of Mo to the support, b = 0.15-0.2%, x is the number of O atoms, x = 2-3, and the molar ratio of nickel to molybdenum is 7-14:1.

[0009] Preferably, the porous biochar is prepared by calcining cellulose, corn stalks, or coffee grounds as carbon sources, adding a pore-forming agent; the pore-forming agent is sodium bicarbonate, sodium carbonate, sodium acetate, potassium carbonate, potassium bicarbonate, or potassium acetate, and the mass percentage of the pore-forming agent to the carbon source is 10-50%; the calcination temperature is 600-900℃, the calcination atmosphere is N2 gas, and the gas flow rate is 80-200 ml / min.

[0010] The preferred carbon source is cellulose, the pore-forming agent is NaHCO3, and the carbonization temperature is 800℃.

[0011] Preferably, a = 0.6%, b = 0.15%, and the molar ratio of metallic nickel to molybdenum is 7:1.

[0012] Preferably, a = 0.8%, b = 0.2%, and the molar ratio of metallic nickel to molybdenum is 7:1.

[0013] Preferably, a = 1%, b = 0.12%, and the molar ratio of metallic nickel to molybdenum is 14:1.

[0014] A method for preparing the above-mentioned highly active catalyst for the hydrogenation and deoxygenation of furfural to 2-methylfuran comprises the following steps:

[0015] Step 1. Weigh a certain amount of porous biochar and ultrasonically disperse it in deionized water to prepare solution A;

[0016] Step 2. Dissolve the nickel salt and molybdenum salt in deionized water to prepare solution B with a metal concentration of 0.1 mol / L. Slowly add solution B to solution A and let it stand at room temperature for 24 hours.

[0017] Step 3. Stir and evaporate to dryness and pretreat in a 5% vol H2 or N2 mixture at 500°C for 3 hours.

[0018] Preferably, the nickel salt is nickel nitrate, nickel chloride, or nickel acetate, and the molybdenum salt is sodium molybdate or ammonium molybdate.

[0019] The aNi-bMoOx / C catalyst prepared in this invention can be used for the hydrodeoxygenation reaction of furfural to prepare 2-methylfuran. The metal content is at most 1.2% of that of the non-metallic support (porous biochar), which not only reduces the cost of the catalyst, but also significantly improves the hydrodeoxygenation activity of furfural and the selectivity of 2-methylfuran. When the molar ratio of nickel to furfural is 1:30, the reaction is carried out at 200°C, and the reaction time is at most 4 hours, the highest furfural conversion rate is 99.9%, and the best 2-methylfuran selectivity is 92.5%. It has the advantages of simple preparation method, low material cost, good catalytic activity, and high specificity of catalytic hydrogenation products. Attached Figure Description

[0020] Figure 1 These are the XRD diffraction patterns of the catalysts in Examples 2, 3, 5, and 9 of this invention.

[0021] Figure 2 These are the XRD diffraction patterns of Embodiment 2 and Comparative Examples 6, 7, and 8 of the present invention. Detailed Implementation

[0022] Example 1:

[0023] The present invention provides a highly active catalyst for the hydrogenation and deoxygenation of furfural to 2-methylfuran, which is carried out in the following steps:

[0024] Step 1. Weigh a certain amount of porous biochar and ultrasonically disperse it in deionized water to prepare solution A;

[0025] The method for preparing the porous biochar is as follows: 3 grams of cellulose and 1.5 grams of NaHCO3 are thoroughly physically mixed and ground in a mortar, then transferred to a quartz boat and placed in a tube furnace. Under a N2 atmosphere at a rate of 80 mL / min, the temperature is increased to 800°C at a rate of 10°C / min for 60 min. After cooling to room temperature, the mixture is ground into powder and dispersed in 200 mL of deionized water. The mixture is then magnetically stirred at room temperature for 12 hours and washed several times with deionized water until the pH of the filtrate is approximately 7. The resulting solid is dried overnight at 70°C to obtain porous biochar.

[0026] Step 2. Dissolve nickel nitrate and sodium molybdate dihydrate in deionized water at a nickel to molar ratio of 7:1 to prepare a solution B with a metal concentration of 0.1 mol / L. Slowly add solution B to solution A and let it stand at room temperature for 24 hours to soak.

[0027] Step 3. Stir and evaporate to dryness and pretreat at 500℃ in a 5% vol H2 atmosphere for 3 hours to obtain a catalyst with a Ni to support mass percentage of 0.6% and a Mo to support mass percentage of 0.15%, named 0.6Ni-0.15MoOx / C-500.

[0028] Example 2:

[0029] The preparation method differs from that in Example 1 in that the mass percentage of Ni to the support is 0.8% and the mass percentage of Mo to the support is 0.2%. The rest is the same as in Example 1. The resulting catalyst is named 0.8Ni-0.2MoOx / C-500.

[0030] Example 3:

[0031] The preparation method differs from Example 1 in that the molar ratio of nickel to molybdenum is 14:1, the mass percentage of Ni to the support is 1%, and the mass percentage of Mo to the support is 0.12%. The rest is the same as in Example 1. The resulting catalyst is named 1Ni-0.12MoOx / C-500.

[0032] Comparative Example 1:

[0033] The preparation process was the same as in Example 1, except that only nickel nitrate solution was used for the metal salt, and the mass percentage of the metal salt to the support was 0.8%. The resulting catalyst was named 0.8Ni / C-500.

[0034] Comparative Example 2:

[0035] The preparation process was the same as in Example 1, except that only sodium molybdate solution was used for the metal salt, and the mass percentage of the metal salt to the support was 0.8%. The resulting catalyst was named 0.8MoOx / C-500.

[0036] Comparative Example 3:

[0037] The preparation method differs from that in Example 1 in that the mass percentage of Ni to the support is 1%, and the mass percentage of Mo to the support is 0.25%. The rest is the same as in Example 1. The resulting catalyst is named 1Ni-0.25MoOx / C-500.

[0038] Comparative Example 4:

[0039] The preparation method differs from that in Example 1 in that the mass percentage of Ni to the support is 1%, and the mass percentage of Mo to the support is 0.5%. The rest is the same as in Example 1. The resulting catalyst is named 1Ni-0.5MoOx / C-500.

[0040] Comparative Example 5:

[0041] The preparation method differs from that in Example 1 in that the mass percentage of Ni to the support is 5% and the mass percentage of Mo to the support is 1%. The rest is the same as in Example 1. The resulting catalyst is named 5Ni-1MoOx / C-500.

[0042] Comparative Example 6:

[0043] The preparation method differs from that in Example 2 in that after stirring and evaporating to dryness, it is pretreated at 400°C in a 5% vol H2 atmosphere for 3 hours. Otherwise, it is the same as in Example 1. The resulting catalyst is named 0.8Ni-0.2MoOx / C-400.

[0044] Comparative Example 7:

[0045] The preparation method differs from that in Example 2 in that the catalyst is stirred and evaporated to dryness and pretreated at 600°C in a 5% vol H2 atmosphere for 3 hours. Otherwise, it is the same as in Example 1. The resulting catalyst is named 0.8Ni-0.2MoOx / C-600.

[0046] Comparative Example 8:

[0047] The preparation method differs from that in Example 2 in that it is stirred and evaporated to dryness and pretreated at 700°C in a 5% vol H2 atmosphere for 3 hours. Otherwise, it is the same as in Example 1. The resulting catalyst is named 0.8Ni-0.2MoOx / C-700.

[0048] Comparative Example 9:

[0049] The preparation method differs from that in Example 1 in that the mass percentage of Ni to the support is 2% and the mass percentage of Mo to the support is 0.5%. Otherwise, it is the same as in Example 1. The resulting catalyst is named 2Ni-0.5MoOx / C-500.

[0050] The XRD diffraction patterns of the catalysts in Example 2 and Comparative Examples 3, 5, and 9 of this invention are as follows: Figure 1 As shown, the characteristic diffraction peaks appearing around 43.8° and 51.2° are attributed to the crystalline phase diffraction peaks of metallic nickel. The metallic nickel diffraction peak intensities of the catalyst in Example 2 and the catalysts in Comparative Examples 3 and 9 are relatively weak, indicating that the metal is highly dispersed on the surface of the porous carbon support.

[0051] The XRD diffraction patterns of Embodiment 2 and Comparative Examples 6-8 of the present invention are as follows: Figure 2 As shown. From Figure 2 It can be seen that the pretreatment temperature affects the intensity of the diffraction peak of the crystal phase of metallic nickel. After pretreatment of the catalyst above 500℃, the diffraction peak of the crystal phase of Ni begins to strengthen, which indicates that the pretreatment temperature of 500℃ can better maintain the high dispersion of metallic Ni.

[0052] Catalytic performance evaluation experiment:

[0053] Experimental method: 1 mmol furfural, 10 ml isopropanol, and catalyst were added to a high-pressure reactor. The amount of catalyst was determined according to the molar ratio n. Ni :n FAL The ratio was 1:30 for quantification. After sealing, the reactor was purged three times with nitrogen, then replaced with hydrogen. The hydrogen pressure was maintained at 1 MPa, the stirring speed was 500 rpm, and the temperature was raised to 180℃ or 200℃ for 120 min or 240 min. After the reaction was completed, the reactor was cooled to room temperature, and the supernatant was collected for qualitative and quantitative analysis by gas chromatography.

[0054] Experimental Results: The activity evaluation diagrams of the catalysts in Examples 1, 2, 3 and Comparative Examples 1-9 of this invention are shown in Table 1. In Table 1, FAL represents furfural, 2-MF represents 2-methylfuran, FOL represents furfuryl alcohol, THFOL represents tetrahydrofurfuryl alcohol, and Other represents other byproducts.

[0055] Table 1

[0056]

[0057] As can be seen from Table 1:

[0058] 1. Under the same reaction conditions, Comparative Example 1 (0.8Ni / C-500) and Comparative Example 2 (0.8MoOx / C-500) both exhibited low catalytic performance, while the catalysts in Comparative Examples 3-7, doped with small amounts of Ni and Mo (<0.2wt%), showed improved catalytic performance, indicating a strong interaction between Ni and Mo. Furthermore, with the increase of metal loading (Ni+Mo) in the catalyst, the conversion rate of furfural and the selectivity for 2-methylfuran gradually decreased. Only Examples 1-3 of this invention exhibited excellent catalytic activity, with the 0.6Ni-0.15MoOx / C-500 catalyst showing the best hydrodeoxygenation catalytic activity, achieving a furfural conversion rate of 99.9% and a 2-MF selectivity of 92.5%.

[0059] 2. Catalysts with different Ni to Mo molar ratios exhibit different catalytic performances. When the Ni to Mo molar ratio is 7:1 or 14:1, the catalyst exhibits good hydrodeoxygenation performance of FAL, achieving a furfural conversion rate of 99.9% and a 2-methylfuran selectivity of up to 92.5% after four hours of reaction. However, when the Ni to Mo molar ratio is 3:1, the catalyst performance is poor, with a furfural conversion rate of only 24.0% and a 2-methylfuran selectivity of 39.4%, while also generating more byproducts.

[0060] 3. The catalytic activity of the 0.6Ni-0.15MoOx / C-500 catalyst in Example 1 was evaluated at 180℃ and 200℃. Under the same other reaction conditions, the furfural conversion rate was 99.9% and the 2-methylfuran selectivity was 89.7% after reacting at 180℃ for 2 hours; the furfural conversion rate was 99.9% and the 2-methylfuran selectivity was 92.5% after reacting at 200℃ for 4 hours.

[0061] 4. The change in pretreatment temperature under H2 / N2 atmosphere has a significant impact on the catalytic performance of the catalyst. Within the pretreatment temperature range of 400-700℃, the furfural conversion rate and 2-MF selectivity of the four catalysts in Example 2 and Comparative Examples 6-8 first increased and then decreased. Among them, the furfural conversion rate on the 0.8Ni-0.2MoOx / C-500 catalyst was 99.9%, and the 2-methylfuran selectivity was 88%, indicating that 500℃ is the optimal pretreatment temperature for the catalyst of this invention.

[0062] Experimental results show that the catalyst prepared according to the mass ratio of metal to porous biochar, the molar ratio of Ni to Mo and the specific pretreatment temperature specified in this invention has high catalytic activity in the preparation of 2-methylfuran by the hydrodeoxygenation reaction of furfural.

Claims

1. An application of furfural hydrogenation deoxygenation to produce 2-methylfuran, characterized in that: The catalyst used in this application is a Ni-Mo bimetallic substrate supported on porous biochar, with the chemical formula aNi-bMoOx / C, where a is the mass percentage of Ni to the support (a=0.6-1%), b is the mass percentage of Mo to the support (b=0.12-0.2%), and x is the number of O atoms (x=2-3). The molar ratio of nickel to molybdenum is 7-14:

1. It is prepared according to the following steps: Step 1. Weigh a certain amount of porous biochar and ultrasonically disperse it in deionized water to prepare solution A; Step 2. Dissolve the nickel salt and molybdenum salt in deionized water to prepare solution B with a metal concentration of 0.1 mol / L. Slowly add solution B to solution A and let it stand at room temperature for 24 hours. Step 3. Stir and evaporate to dryness and pretreat in a 5% vol H2 / N2 mixture at 500℃ for 3 hours; The porous biochar is prepared by calcining cellulose as a carbon source and adding sodium bicarbonate as a pore-forming agent; the mass percentage of the pore-forming agent to the carbon source is 50%; the calcination temperature is 800℃, the calcination atmosphere is N2 gas, and the gas flow rate is 80 ml / min.

2. The application of furfural hydrogenation deoxygenation to 2-methylfuran according to claim 1, characterized in that: The values ​​are a=0.6%, b=0.15%, and the molar ratio of metallic nickel to molybdenum is 7:

1.

3. The application of furfural hydrogenation deoxygenation to 2-methylfuran according to claim 1, characterized in that: The values ​​are a=0.8%, b=0.2%, and the molar ratio of metallic nickel to molybdenum is 7:

1.

4. The application of furfural hydrogenation deoxygenation to 2-methylfuran according to claim 1, characterized in that: The values ​​are a=1%, b=0.12%, and the molar ratio of nickel to molybdenum is 14:1.

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