Nb-based composite oxide supported metal catalyst, preparation method and application of Nb-based composite oxide supported metal catalyst in preparation of aviation oil by hydrodeoxygenation
By supporting metal catalysts with Nb-based composite oxides and combining them with γ-Al2O3 and NbOPO4 supports, the problems of high cost and insufficient activity of existing catalysts have been solved, achieving efficient hydrodeoxygenation reaction and improving the conversion efficiency of biomass derivatives and the stability of the catalyst.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTHEAST UNIV
- Filing Date
- 2026-02-26
- Publication Date
- 2026-05-05
AI Technical Summary
Existing hydrodeoxygenation catalysts are costly and lack sufficient catalytic activity, making it difficult to meet the needs of industrial applications. In particular, they are problematic in the process of converting biomass derivatives into long-chain alkanes that meet aviation fuel standards, due to high catalyst costs, harsh reaction conditions, and alkane products with carbon chain lengths that do not meet standards.
A metal catalyst supported on a Nb-based composite oxide was prepared by using a mixture of Nb, Al, O and P elements as a support and combining it with metals such as Pt, Pd, Rh, Ru, Ni, Co and Cu. The catalyst has superior activity and stability. The hydrodeoxygenation performance of the catalyst is improved by utilizing the acidic sites of γ-Al2O3 and the deoxygenation properties of NbOPO4.
It achieved a highly efficient hydrodeoxygenation reaction, improved the activity and stability of the catalyst, enhanced the metal reducing power, reduced carbon deposition, and increased the reaction conversion rate and aviation fuel yield, reaching a maximum yield of 79.6%.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalysis, specifically relating to an Nb-based composite oxide supported metal catalyst and its preparation method, as well as its application in hydrodeoxygenation to produce aviation fuel. Background Technology
[0002] Given the irreversible depletion of global non-renewable resources, the ever-increasing demand for fuels, and potential concerns about the greenhouse effect, the development of new, sustainable, and environmentally friendly energy sources for the synthesis of liquid fuels is imperative. In this context, biomass is considered the most promising resource for the production of hydrocarbon liquid fuels.
[0003] To achieve this goal of converting biomass into high-value-added fuels or chemicals, furfural, a hydrolysis product of lignocellulose, is selected as a raw material. It undergoes an aldol condensation reaction with other small-molecule ketones obtainable from biomass conversion to extend the carbon chain, yielding long-chain oxygenated compounds with a carbon chain number that meets fuel standards. These are then subjected to a hydrodeoxygenation reaction to obtain long-chain alkanes. This process allows for the adjustment of ketones to obtain alkanes with different properties, thereby modifying fuel performance. However, due to the complex molecular structure of the resulting condensation products and the multiple reaction steps involved in the hydrodeoxygenation process, optimization of reaction conditions and catalysts is necessary to achieve efficient conversion and utilization.
[0004] Hydrodeoxygenation catalysts need to possess both hydrogenation sites and deoxygenation sites. Hydrogenation sites are typically metallic, while deoxygenation sites are acidic. Currently developed hydrodeoxygenation (HDO) catalysts generally face numerous challenges, such as high catalyst costs, insufficient catalytic activity leading to harsh reaction conditions, and the resulting alkane products having carbon chain lengths that do not meet aviation fuel standards. These factors severely limit their practical industrial application.
[0005] Most studies still use precious metal catalysts for hydrodeoxygenation, which, while offering superior performance, are expensive. Therefore, there is an urgent need for a catalyst that is less expensive and has stronger hydrodeoxygenation performance. Summary of the Invention
[0006] The purpose of this invention is to provide a method for preparing an Nb-based composite oxide supported metal catalyst and its application in hydrodeoxygenation to produce aviation fuel. The catalyst prepared by this method has superior activity and stability.
[0007] To achieve the above objectives, the technical solution provided by the present invention is as follows:
[0008] A Nb-based composite oxide supported metal catalyst, denoted as xM / NyAz, wherein the catalyst comprises one or more hydrogenation-active metals, and the catalyst support comprises a mixture of Nb, Al, O and P elements, wherein M and x are the metal and the metal loading, respectively, N and A represent the Nb-containing support and the γ-Al2O3 support, respectively, and the ratio of y to z represents the mass ratio between the two supports.
[0009] Furthermore, the hydrogenation active metal is one or more selected from Pt, Pd, Rh, Ru, Ni, Co, and Cu.
[0010] Furthermore, the hydrogenation active metal component in the catalyst accounts for 0.2 to 20 wt% of the catalyst mass.
[0011] Furthermore, the Nb-containing support includes Nb₂O₅ and NbOPO₄, which have similar properties.
[0012] Furthermore, based on the total mass of the catalyst, the mass ratio of the two supports in the catalyst is 0 to 4:1.
[0013] According to another aspect of the present invention, a method for preparing a hydrodeoxygenation catalyst is provided, comprising:
[0014] The Nb support, γ-Al2O3 support, metal salt solution, and dispersant were placed in a beaker and mixed. The mixture was stirred at room temperature, heated until the water evaporated, dried, calcined in an air atmosphere, and then reduced in a hydrogen-inert gas mixture to obtain an Nb-based composite oxide supported metal catalyst.
[0015] Furthermore, the dispersant is ethanol or ethylene glycol, and the mass ratio of the dispersant to the carrier is (1~4) mL: 8 g.
[0016] Furthermore, the stirring time at room temperature is 6~24h.
[0017] Furthermore, the drying conditions are: drying at 90~100℃ for 12h~36h.
[0018] Furthermore, the calcination conditions in the air atmosphere are as follows: first, the temperature is raised to 240~260℃ and held for 1~3 hours, then the temperature is raised to 350~750℃ and calcined for 4~6 hours, with a heating rate of 2℃ / min.
[0019] Furthermore, the reduction conditions are as follows: under an atmosphere of 8~12 vol% H2 / Ar (8~12 vol% is the volume ratio of H2 in the overall gas), the temperature is first raised to 240~260℃ and held for 1~3h, then raised to 400~600℃ for reduction for 2~6h, with a heating rate of 1~3℃ / min during the heating process.
[0020] Furthermore, the metal salt is selected from the group consisting of nitrates, sulfates, chlorides, acetates, and combinations thereof, and preferably the hydrogenation active metal source is selected from one or more of palladium nitrate, palladium sulfate, palladium chloride, palladium acetate, and nickel nitrate.
[0021] According to another aspect of the present invention, a method for preparing alkanes using a hydrodeoxygenation catalyst is provided, the method comprising: in the presence of the catalyst and an organic solvent, subjecting a condensation product of furfural and ketones to a hydrodeoxygenation reaction to generate C8-C16 alkanes.
[0022] Furthermore, the hydrodeoxygenation reaction is carried out at a temperature of 200℃~280℃, a hydrogen pressure of 1MPa~5MPa, and under stirring for 2h~10h.
[0023] Furthermore, the organic solvent is cyclohexane, and the ketones are acetone, 2-butanone, 3-pentanone, 2-hexanone, 2,5-hexanedione, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and acetylpropionic acid.
[0024] Furthermore, the ratio of the reaction substrate, catalyst, and solvent is 0.1 g:(0.01~0.04 g):5 mL.
[0025] Beneficial effects
[0026] This invention uses the transition metal Ni as the active hydrogenation center, which has the advantages of fast reaction rate and high selectivity in hydrodeoxygenation reactions, and its cost is significantly lower than that of noble metals. γ-Al2O3 is a high-performance acidic support, and Nb2O5 (or NbOPO4) plays a key role in the breaking of CO bonds, making it a promising material for deoxygenation reactions. In the preparation method of this invention, two different supports, γ-Al2O3 and Nb-containing support, are mixed. Through the interaction between the supports, the acidity and hydrodeoxygenation activity of the catalyst itself are improved, resulting in a catalyst with stronger hydrodeoxygenation performance compared to a single-support catalyst with the same loading. Its performance in the hydrodeoxygenation of biomass derivative aldol condensation products (long-chain oxygen-containing compounds) to produce aviation fuel is far superior to that of a single-support catalyst with the same metal loading. Furthermore, the presence of the composite support facilitates metal reduction, enhances metal reducing power, and improves the catalyst's hydrogenation performance. This results in very high hydrodeoxygenation activity for aldol condensation products of biomass derivatives such as furfural, levulinic acid, and cyclopentanone, achieving a maximum aviation fuel yield of 79.6%. Simultaneously, the hydrodeoxygenation catalyst of this application retains the mesoporous structure of γ-Al₂O₃, providing sufficient sites for supporting active metals and a large reactant contact area, which helps improve reaction conversion. The mesoporous structure of the composite oxide provides sufficient substrate-catalyst contact area, enhancing catalyst activity while reducing carbon deposition and improving catalyst stability. Attached Figure Description
[0027] Figure 1 NH3-TPD diagrams of different catalysts and supports prepared in this invention;
[0028] Figure 2 Py-IR spectra of different catalysts and supports prepared in this invention;
[0029] Figure 3 H2-TPR diagrams of different unreduced catalysts prepared in this invention;
[0030] Figure 4 XPS spectra (Ni2p) of different catalysts prepared in this invention;
[0031] Figure 5 The nitrogen adsorption diagrams are for different catalysts and supports prepared in this invention. Detailed Implementation
[0032] To make the objectives, features, and advantages of this invention more apparent and understandable, the technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.
[0033] The present invention aims to prepare a hydrodeoxygenation catalyst that combines the advantages of existing Nb2O5 (or NbOPO4) and γ-Al2O3 as supports in the hydrodeoxygenation reaction, and achieves superior performance compared to single-support catalysts.
[0034] Based on this, according to some embodiments of the present invention, the present invention provides a hydrodeoxygenation catalyst comprising a mixture of Nb, Al, O and P elements, and the catalyst is represented by xM / NyAz, where M and x are the metal and metal loading, respectively, N and A represent two supports, namely Nb-containing support and γ-Al2O3, respectively, and the ratio of y to z represents the mass ratio between the two supports.
[0035] In some embodiments, one or more hydrogenation-active metals are Pt, Pd, Rh, Ru, Ni, Co, Cu, and combinations thereof. Preferably, one or more hydrogenation-active metals are Ni or Pd.
[0036] In some embodiments, the active metal component of the catalyst accounts for 0.2 to 20 wt% of the catalyst mass; exemplary embodiments include 10 wt%, 12.5 wt%, 15 wt%, 17.5 wt%, and 20 wt% of the catalyst mass.
[0037] In some embodiments, the Nb-containing support comprises Nb₂O₅ and NbOPO₄, which have similar properties. More preferably, the Nb-containing support is Nb₂O₅.
[0038] In some embodiments, the mass ratio of the two supports in the catalyst support is 0 to 4:1. For example, the mass ratio of the two supports is 0:1, 1:4, 1:2, 1:1, 2:1, 4:1, or 1:0.
[0039] On the other hand, embodiments of the present invention also provide a method for preparing a hydrodeoxygenation catalyst, comprising: mixing two supports, a metal salt solution, and a dispersant in a beaker, stirring at room temperature, heating to evaporate the water, drying, calcining in an air atmosphere, and then reducing in a hydrogen-inert gas mixture to obtain the hydrodeoxygenation catalyst.
[0040] In some embodiments, the dispersant is ethanol or ethylene glycol, and its mass ratio to the carrier is (1~4) mL:8 g. Preferably, the dispersant is ethylene glycol, and the mass ratio of the remaining carrier is 3 mL:8 g.
[0041] In some embodiments, the mixing time at room temperature is 6 to 24 hours. More preferably, the mixing time at room temperature is 12 hours.
[0042] In some embodiments, the drying conditions are: drying at 100°C for 12 to 36 hours. Exemplarily, drying at 100°C for 12, 24, or 36 hours.
[0043] In some embodiments, the calcination conditions in the air atmosphere are as follows: first, the temperature is raised to 250°C and held for 2 hours, then the temperature is raised to 350~750°C and calcined for 4~6 hours, with a heating rate of 2°C / min. Exemplarily, the calcination temperature can be 350°C, 450°C, 550°C, 650°C, or 750°C, and the calcination time is at least 4 hours.
[0044] In some embodiments, the reduction conditions are as follows: under a 10% H2 / Ar atmosphere, first heat to 250°C, hold at that temperature for 2 hours, then heat to 400~600°C for reduction for 2~6 hours, with a heating rate of 2°C / min. For example, the reduction temperature can be 450°C, and the reduction time can be at least 2 hours.
[0045] In some embodiments, the hydrogenated active metal source is selected from one or more of nitrates, sulfates, chlorides, and acetates, and preferably nickel nitrate and palladium chloride.
[0046] In another aspect, embodiments of the present invention provide a method for preparing alkanes using a hydrodeoxygenation catalyst, the method comprising: in the presence of the hydrodeoxygenation catalyst and an organic solvent, subjecting furfural and the condensation products of different ketones to a hydrodeoxygenation reaction to obtain different types of alkanes.
[0047] Preferably, the reaction of the condensation product, the organic solvent, and the hydrodeoxygenation catalyst is carried out in a stainless steel high-pressure reactor with a polytetrafluoroethylene liner.
[0048] In some embodiments, the hydrodeoxygenation reaction is carried out at a temperature of 200°C to 280°C, a hydrogen pressure of 1 MPa to 5 MPa, and under stirring for 2 to 10 hours. Exemplarily, the hydrodeoxygenation reaction temperatures are 200°C, 220°C, 240°C, 260°C, and 280°C; the hydrogen pressures are 1 MPa, 2 MPa, 3 MPa, 4 MPa, and 5 MPa; and the reaction times are 2 hours, 4 hours, 6 hours, 8 hours, and 10 hours.
[0049] In some embodiments, the organic solvent is cyclohexane, and the ketones are acetone, 2-butanone, 3-pentanone, 2-hexanone, 2,5-hexanedione, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and levulinic acid. The ratio of reaction substrate, catalyst, and solvent is 0.1 g:(0.01~0.04 g):5 mL.
[0050] The present application will be further described in detail below with reference to specific embodiments and accompanying drawings. These embodiments should not be construed as limiting the scope of protection claimed in this application.
[0051] Examples 1-25
[0052] A method for preparing a hydrodeoxygenation catalyst, comprising:
[0053] The calculated mass of nickel nitrate hexahydrate (calculated by the metal loading of the catalyst, where the loading is nickel nitrate hexahydrate / (nickel nitrate hexahydrate + support)) can be 10 wt%, 12.5 wt%, 15 wt%, 17.5 wt%, 20 wt%, etc. The 15 catalysts (wt%) were dissolved in 8.5 mL of water. Two supports (1:1, 1:2, 2:1) with different mass ratios of Nb₂O₅ and γ-Al₂O₃ (total mass 8.5 g), 3 mL of ethylene glycol, and nickel nitrate solution were mixed and stirred at room temperature for 12 h. The mixture was then heated until the water evaporated and dried at 100 °C for 24 h. Afterward, the mixture was calcined in air under the following conditions: first, the temperature was raised to 250 °C and held for 2 h, then raised to 450 °C and calcined for 4 h, with a heating rate of 2 °C / min. Following this process, the mixture was reduced under a 10% H₂ / Ar atmosphere under the following conditions: first, the temperature was raised to 250 °C and held for 2 h, then raised to 450 °C and reduced for 2 h, with a heating rate of 2 °C / min. These processes yielded the 15 catalysts listed in Table 1.
[0054] Table 1 Catalysts corresponding to Examples 1-25
[0055]
[0056] Applications of hydrodeoxygenation catalysts in the preparation of alkanes from condensation products include:
[0057] In the presence of the hydrodeoxygenation catalyst prepared by the above method and cyclohexane, the condensation product of furfural and cyclopentanone undergoes a hydrodeoxygenation reaction to obtain different types of alkanes. The hydrodeoxygenation reaction is carried out at a temperature of 200℃~280℃ and a hydrogen pressure of 4MPa for 8 hours with stirring. The ratio of reaction substrate, catalyst, and solvent is 0.1g:0.04g:5mL.
[0058] Using different metal loading, different carrier mass ratios, and different reaction temperatures as three influencing factors, an orthogonal table was constructed, resulting in Examples 1 to 25.
[0059] Table 2 Results of Examples 1-25
[0060]
[0061] The above results indicate that with a Ni loading of 15 wt%, the total alkane yield of the hydrodeoxygenation reaction is highest at 280 °C, achieving the best technical effect. This is because the higher loading provides sufficient hydrogenation active sites, but further increasing the metal loading has a smaller gain on catalyst activity. The higher temperature brings stronger molecular kinetic energy, allowing more molecules to have energy exceeding the activation energy, thus achieving a higher hydrodeoxygenation yield.
[0062] Examples 26-27
[0063] An application of a hydrodeoxygenation catalyst in the preparation of alkanes from condensation products includes:
[0064] In the presence of the prepared hydrodeoxygenation catalyst and cyclohexane, the condensation product of furfural and cyclopentanone was subjected to hydrodeoxygenation to obtain different types of alkanes. The hydrodeoxygenation reaction was carried out at 280°C, under a hydrogen pressure of 4 MPa, and with stirring for 8 h. The ratio of reaction substrate, catalyst, and solvent was 0.1 g:0.04 g:5 mL.
[0065] Hydrogenation deoxygenation tests were conducted on three catalysts (catalysts 7, 8, and 9) with the same metal loading of 15 wt% but different support mass ratios, resulting in Examples 26-27 and Example 13.
[0066] Comparative Examples 1-4
[0067] A method for preparing a hydrodeoxygenation catalyst, comprising:
[0068] 1.5 g of nickel nitrate hexahydrate was dissolved in 8.5 mL of water. Two supports with different Nb₂O₅ / γ-Al₂O₃ mass ratios (1:4, 4:1, 1:0, 0:1), 3 mL of ethylene glycol, and the nickel nitrate solution were mixed and stirred at room temperature for 12 h. The mixture was then heated until the water evaporated and dried at 100 °C for 24 h. Afterward, it was calcined in air under the following conditions: first, the temperature was raised to 250 °C and held for 2 h, then raised to 450 °C and calcined for 4 h, with a heating rate of 2 °C / min. Subsequently, it was reduced under a 10% H₂ / Ar atmosphere under the following conditions: first, the temperature was raised to 250 °C and held for 2 h, then raised to 450 °C and reduced for 2 h, with a heating rate of 2 °C / min. These processes yielded the four catalysts shown in Table 3.
[0069] Table 3 Catalysts with different support mass ratios and all having a metal loading of 15 wt%.
[0070]
[0071] An application of a hydrodeoxygenation catalyst in the preparation of alkanes from condensation products includes:
[0072] In the presence of the prepared hydrodeoxygenation catalyst and cyclohexane, the condensation product of furfural and cyclopentanone was subjected to hydrodeoxygenation to obtain different types of alkanes. The hydrodeoxygenation reaction was carried out at 280°C, under a hydrogen pressure of 4 MPa, and with stirring for 8 h. The ratio of reaction substrate, catalyst, and solvent was 0.1 g:0.04 g:5 mL.
[0073] Hydrogenation deoxygenation tests were conducted on catalysts 16-19, all with a metal loading of 15 wt% but different support mass ratios, under the same conditions, forming comparative examples 1-4.
[0074] Table 4. Comparison of the effects of catalysts with different support mass ratios and all having a metal loading of 15 wt%.
[0075]
[0076] The above results show that the total alkane yield is highest and the best technical effect is achieved when the mass ratio of Nb2O5 to γ-Al2O3 is 2:1. Due to the difference in the catalyst support ratio between Examples 13, 26, and 27 and Comparative Examples 1-4, the effects of Examples 13, 26, and 27 are better than those of Comparative Examples 1-4. This indicates that the activity of a dual-support catalyst with a suitable ratio is better than that of a single-support catalyst or a dual-support catalyst with fewer components. This is because the mixed-support catalyst has stronger medium-to-strong acidity and hydrogenation performance compared to the single-support catalyst, as shown in Tables 10 and 11.
[0077] Comparative Examples 5-7
[0078] The calculated mass of palladium chloride was dissolved in 5 mL of water. 1 g of the support NbOPO4, 1 mL of ethylene glycol, and the palladium chloride solution were mixed and stirred at room temperature for 12 h. The mixture was then heated until the water evaporated, and dried at 100 °C for 24 h. Afterward, it was calcined in air at 500 °C for 3 h, with a heating rate of 2 °C / min. Subsequently, it was reduced in a 10% H2 / Ar atmosphere at 300 °C for 2 h, with a heating rate of 2 °C / min. These processes yielded the three catalysts shown in Table 5.
[0079] Table 5. Pd catalysts with different loadings prepared.
[0080]
[0081] An application of a hydrodeoxygenation catalyst in the preparation of alkanes from condensation products includes:
[0082] In the presence of the prepared hydrodeoxygenation catalyst and cyclohexane, the condensation product of furfural and cyclopentanone was subjected to hydrodeoxygenation to obtain different types of alkanes. The hydrodeoxygenation reaction was carried out at 280°C, under a hydrogen pressure of 4 MPa, and with stirring for 8 h. The ratio of reaction substrate, catalyst, and solvent was 0.1 g:0.04 g:5 mL.
[0083] The prepared noble metal catalysts were subjected to hydrogenation deoxygenation tests under the same conditions as the Ni catalyst for comparison, forming comparative examples 5-7.
[0084] Table 6 shows the effects of Pd catalysts with different loadings.
[0085]
[0086] The above results indicate that the highest total alkane yield and best technical performance are achieved when the Pd / NbP metal loading is 4 wt%. This is because a higher Pd loading provides more hydrogenation sites, thus improving the hydrodeoxygenation activity. Pd / NbOPO4 is the most classic hydrodeoxygenation catalyst for condensation products in most studies, and the cost of noble metals is much higher than that of transition metal Ni. However, even with the Pd loading increased to 4 wt%, the effect is still weaker than that of the prepared 15Ni / N2Al, demonstrating the advantages of mixed support catalysts.
[0087] Examples 28-29
[0088] An application of a hydrodeoxygenation catalyst in the preparation of alkanes from condensation products includes:
[0089] In the presence of catalyst 9 and cyclohexane, the condensation product of furfural and cyclopentanone was subjected to hydrodeoxygenation to yield different types of alkanes. The hydrodeoxygenation reaction was carried out at 280°C, under hydrogen pressure of 3.5 MPa, and with stirring for 8 h. The ratio of substrate, catalyst, and solvent was 0.1 g:0.04 g:5 mL.
[0090] Table 7 Effect of initial hydrogen pressure on hydrodeoxygenation reaction
[0091]
[0092] The above results indicate that the total yield of alkanes is highest and the best technical effect is achieved when the hydrogen pressure is 4 MPa. This is because the high initial pressure is conducive to the contact between H2 and the reaction substrate, which shifts the chemical reaction equilibrium to the right. When the pressure is greater than 4 MPa, further increasing the pressure has little effect on the HDO reaction.
[0093] Examples 30-32
[0094] An application of a hydrodeoxygenation catalyst in the preparation of alkanes from condensation products includes:
[0095] In the presence of catalyst 9 and cyclohexane, the condensation product of furfural and cyclopentanone was subjected to hydrodeoxygenation to yield different types of alkanes. The hydrodeoxygenation reaction was carried out at 280°C, under a hydrogen pressure of 4 MPa, and with stirring for 6, 10, and 12 h. The ratio of substrate, catalyst, and solvent was 0.1 g:0.04 g:5 mL.
[0096] Table 8. Effect of different reaction times on hydrodeoxygenation reaction
[0097]
[0098] The above results indicate that the total alkane yield is highest when the reaction time is 8 hours, achieving the best technical effect. This is because the total alkane yield Y increases with increasing reaction time. HDO Increasing the reaction time first and then decreasing it will result in insufficient HDO reaction and reduced yield if the reaction time is too short, while increasing the reaction time will cause excessive cracking, resulting in a reduction in the number of alkanes that meet the carbon number requirements of aviation fuel.
[0099] Examples 33-40
[0100] An application of a hydrodeoxygenation catalyst in the preparation of alkanes from condensation products includes:
[0101] In the presence of catalyst 9 and cyclohexane, the condensation products of furfural and various ketones were subjected to hydrodeoxygenation to yield different types of alkanes. The hydrodeoxygenation reaction was carried out at 280°C, under a hydrogen pressure of 4 MPa, and with stirring for 8 hours. The ratio of reaction substrate, catalyst, and solvent was 0.1 g:0.04 g:5 mL. The various ketones included acetone, 2-butanone, 3-pentanone, 2-hexanone, 2,5-hexanedione, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and levulinic acid, forming Examples 33-40.
[0102] Table 9. Effects of catalysts on the hydrodeoxygenation reaction of different substrates
[0103]
[0104] Preparation of condensation products
[0105] The typical condensation product, the condensation product of furfural and cyclopentanone, is prepared as follows: 3.92 g of furfural and 1.68 g of cyclopentanone (molar ratio 2:1) are added to 40 mL and 20 mL of deionized water, respectively. After thorough mixing with water, the mixture is added to a three-necked flask for preheating. Under stirring at 40°C, 30 mL of 0.5 M NaOH solution is added dropwise to the three-necked flask using a separatory funnel. The reaction is allowed to proceed for 4 hours. After the reaction is complete, a large amount of yellow solid product is obtained by suction filtration. After washing with deionized water and freeze-drying, the condensation product, which can be directly used for hydrodeoxygenation reactions, is obtained. The preparation process for other condensation products is mostly the same as that for the furfural-cyclopentanone condensation product. It should be noted that the condensation reaction of furfural and levulinic acid requires a slightly higher concentration of NaOH solution (1 M), and acidification with dilute sulfuric acid is required after the reaction to precipitate the solid product.
[0106] In addition, the condensation of furfural with hexanone, furfural with 2,5-hexanedione, and furfural with methyl isobutyl ketone were prepared using a milder solid base catalysis to prevent the formation of polymers with excessively long carbon chains. After the reaction, the catalyst was separated by centrifugation, and the solvent and raw materials were removed in a micro-sample distillation apparatus to obtain the condensation products.
[0107] Characterization and Testing
[0108] 1) The catalysts (3, 7, 8, 9, 15, 18, 19) prepared in this invention and their corresponding supports were characterized by NH3-TPD and Py-IR to test their acidity. The results are as follows: Figure 1 , 2 As shown.
[0109] from Figure 1 , 2 The calculation results show that even compared to the highly acidic single-supported catalyst Ni / γ-Al2O3, the prepared dual-supported catalyst still has a stronger total acidity, and its medium-strong acid content is higher than that of the two single-supported catalysts. Table 10 shows the acidity data for different strengths obtained by NH3-TPD and Py-IR.
[0110] Table 10. Acidity of different strengths for catalysts and supports
[0111]
[0112] 2) The catalysts (3, 7, 8, 9, 15, 18, 19) prepared in this invention were subjected to H2-TPR testing under unreduced conditions to test the difficulty of Ni metal reduction. The results are as follows: Figure 3 As shown.
[0113] from Figure 3 It can be seen that all catalysts exhibit a reduction peak at 450℃, while the peak for bimetallic catalysts corresponds to a lower temperature than that for monometallic catalysts. After the same reduction at 450℃, the resulting catalyst contains Ni... 0 The species content needs to be higher.
[0114] 3) The catalysts (7, 8, 9, 18, 19) prepared in this invention were characterized by XPS, and their Ni 2p spectra were obtained as follows. Figure 4 As shown.
[0115] from Figure 4 It can be seen that Ni in single-metal catalysts 0 The species content was indeed lower than that of the bimetallic catalyst, demonstrating the superior hydrogenation performance of the bimetallic catalyst. The Ni content in the catalyst was obtained via XPS. 0 and Ni 2+ The relative contents are shown in Table 11.
[0116] Table 11 Ni in the catalyst 0 and Ni 2+ relative content
[0117]
[0118] 4) The catalysts (3, 7, 8, 9, 15, 18, 19) prepared in this invention and their corresponding supports were subjected to nitrogen adsorption tests, and the results are as follows: Figure 5 As shown in Table 12, the specific surface area, pore size, pore volume, and other data of the catalyst and support obtained by BET calculations are presented.
[0119] Depend on Figure 5 As can be seen from Table 12, the catalyst retains the mesoporous structure of γ-Al2O3 after mixing, possessing sufficient specific surface area, which is beneficial for the hydrodeoxygenation reaction.
[0120] Table 11 Pore data of the catalyst
[0121]
[0122] It should be understood that the various forms of processes shown above can be used to reorder, add, or delete steps. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this invention can be achieved, and this is not limited herein.
[0123] Of course, the present invention may have other various embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the claims of the present invention.
Claims
1. A Nb-based composite oxide supported metal catalyst, characterized in that, The catalyst is denoted as xM / NyAz and contains one or more hydrogenation-active metals, where M and x are the metal and metal loading, respectively, N and A represent Nb-containing support and γ-Al2O3 support, respectively, and the ratio of y to z represents the mass ratio between the two supports.
2. The Nb-based composite oxide supported metal catalyst according to claim 1, characterized in that, The hydrogenation active metal is one or more of Pt, Pd, Rh, Ru, Ni, Co, and Cu; the Nb-containing support includes Nb2O5 and NbOPO4.
3. The Nb-based composite oxide supported metal catalyst according to claim 1, characterized in that, Based on the total mass of the catalyst, the hydrogenation active metal component in the catalyst accounts for 0.2~20wt% of the catalyst mass; the mass ratio of the two supports in the catalyst is 0~4:
1.
4. The method for preparing the Nb-based composite oxide supported metal catalyst according to claim 1, characterized in that: include: The Nb support and γ-Al2O3 support, metal salt solution, and dispersant were mixed, stirred at room temperature, heated until the water evaporated, dried, calcined in an air atmosphere, and then reduced in a hydrogen-inert gas mixture to obtain an Nb-based composite oxide supported metal catalyst.
5. The method for preparing the Nb-based composite oxide supported metal catalyst according to claim 4, characterized in that, The dispersant is ethanol or ethylene glycol, and the ratio of dispersant to carrier is 1~4mL:8g.
6. The method for preparing the Nb-based composite oxide supported metal catalyst according to claim 4, characterized in that, The stirring time at room temperature is 6-24 h; the drying conditions are: drying at 90-100℃ for 12-36 h; the calcination conditions in air atmosphere are: first heating to 240-260℃, holding for 1-3 h, then heating to 350-750℃, calcining for 4-6 h, with a heating rate of 1-3℃ / min; the reduction conditions are: in an 8-12 vol% H2 / Ar atmosphere, first heating to 240-260℃, holding for 1-3 h, then heating to 400-600℃ for reduction for 2-6 h, with a heating rate of 1-3℃ / min.
7. The method for preparing the Nb-based composite oxide supported metal catalyst according to claim 4, characterized in that, The metal salt is one or more of palladium nitrate, palladium sulfate, palladium chloride, palladium acetate, and nickel nitrate.
8. The application of the catalyst according to any one of claims 1 to 3 in the hydrodeoxygenation of aviation fuel, characterized in that, The method includes: In the presence of the catalyst and organic solvent, the condensation products of furfural and ketones undergo a hydrodeoxygenation reaction to generate C8-C16 alkanes.
9. The application according to claim 8, characterized in that, The hydrodeoxygenation process for producing aviation fuel involves stirring the composition for 2 to 10 hours at a temperature of 200°C to 280°C and a hydrogen pressure of 1 MPa to 5 MPa. The organic solvent is cyclohexane, and the ketones are one or more of the following: acetone, 2-butanone, 3-pentanone, 2-hexanone, 2,5-hexanedione, methyl isobutyl ketone, cyclopentanone, cyclohexanone, and levulinic acid.
10. The application according to claim 8, characterized in that, The ratio of reaction substrate, catalyst, and organic solvent is 0.1 g : 0.01~0.04 g : 5 mL.