Method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds
Through the chemical reaction of eucalyptus oil and phenolic compounds and combined with the action of catalysts, high-density aviation fuel was successfully prepared, solving the problem of traditional fuel production relying on oil and environmental pollution, and achieving green, sustainable and efficient production.
Patent Information
- Application Number
- CN202510381969.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-28
- Publication Date
- 2025-06-03
AI Technical Summary
The production of existing high-density aviation fuels depends on petroleum resources, and traditional synthesis technologies have problems of environmental pollution and high costs, making it difficult to achieve green and sustainable production.
Eucalyptus oil and phenolic compounds are used as raw materials to promote isomerization and alkylation reactions through an acid catalyst, and then hydrodeoxygenation is carried out under the joint action of Metal/C and solid acid catalyst to prepare high-density aviation fuel.
The green synthesis of high-density aviation fuel is achieved, with a fuel density greater than 0.90g/mL, and has good combustion performance and low temperature stability, which reduces production costs and avoids environmental pollution.
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Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of organic synthesis of compounds, and specifically relates to a method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds. Background Art
[0002] Hydrocarbon high-density fuel is a liquid hydrocarbon compound with a density greater than 0.80 g / cm 3 , which has a high energy density and volumetric calorific value, and is widely used in the aerospace field, such as airplanes, rockets, missiles, spacecrafts, and satellites. Its development background mainly stems from the need to improve the performance of aircraft and the pursuit of sustainable development. Traditional high-density fuels are mainly synthesized from petrochemicals. However, with the depletion of fossil energy and the exacerbation of environmental pollution problems, green synthesis technologies have gradually become the research focus. In recent years, the synthesis of high-density fuels from biomass resources has received extensive attention. For example, high-density fuels synthesized from lignocellulosic platform molecules can significantly increase the fuel density and volumetric calorific value by constructing polycyclic alkane structures. In addition, monoterpenes and sesquiterpenes from biomass sources are also used to synthesize high-density fuels, but the problem of high low-temperature viscosity needs to be solved. From a technical perspective, the performance of hydrocarbon high-density fuels not only depends on their molecular backbone structures, such as straight-chain, branched-chain, and cyclic structures, but also is closely related to the spatial configuration. Research shows that the more carbon atoms and rings in the molecule, the greater the fuel density. For example, the density of rocket kerosene mainly composed of naphthenes can reach 0.83 g / cm 3 , which is much higher than that of paraffinic aviation kerosene. In addition, through the introduction of photocatalytic technology and green catalysts, the green synthesis of high-density fuels can be realized. With the increasing demand for high-density fuels, their research direction is gradually developing towards high energy, greenness, and high performance. In the future, how to further improve the energy density of fuels, reduce the freezing point, optimize the low-temperature performance, and achieve sustainable production will be the focus of research on hydrocarbon high-density fuels.
[0003] Phenolic compounds have always had important uses in our production and life. For example, phenolic resins widely used in production and life are mainly condensed from phenolic compounds (such as cresol and xylenol) and formaldehyde, and have good corrosion resistance, heat resistance, and mechanical properties (Energy & Fuels, 2021, 35(22): 18385-18395). In the pharmaceutical field, phenolic compounds mainly play the role of intermediates. For example, salicylic acid (o-hydroxybenzoic acid) is an intermediate for the drug aspirin. In the cosmetics field, 4-methoxyphenolic compounds are intermediates for the antioxidant BHA (3-tert-butyl-4-hydroxyanisole), and they all play irreplaceable roles. Similarly, from the perspective of saving resources and protecting the environment, the catalytic conversion of lignin phenolic platform compounds into polycyclic alkane fuels is a promising direction. Summary of the Invention
[0004] The object of the present invention is to provide a method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds, which can simplify the preparation steps, improve the yield, and can obtain high-density aviation fuel with excellent performance.
[0005] To achieve the above object, the technical solution adopted by the present invention is as follows: A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds, comprising the following steps:
[0006] S1. Under the catalysis of an acid catalyst, eucalyptus oil and phenolic compounds are added to a solvent in a molar ratio of 1:(0.6 - 1.0). The eucalyptus oil first undergoes an isomerization reaction and then dehydration to undergo an alkylation reaction with the phenolic compounds to obtain an alkylated product having a bicyclic structure and a tricyclic structure;
[0007] S2. The alkylated product prepared in step S1 is added to a solvent and undergoes hydrodeoxygenation under the co-catalysis of Metal / C and a solid acid catalyst to generate high-density aviation fuel.
[0008] Preferably, in step S1, the acid catalyst is p-toluenesulfonic acid, SBA-15, SF resin, T-62MP, Amberlyst15, Al-MCM-41, MCM-41, HPW / SiO 2 , HPW / MCM-41, D600, CD750, CD250, SO 4 / ZrO 2 -TiO 2 or one or more of them.
[0009] Preferably, in step S1, the mass of the acid catalyst is 10% of the total mass of the eucalyptus oil; the reaction temperature is 60 - 160 °C, the reaction time is 9 - 21 h; the substrate concentration is 10 - 15 mol / L.
[0010] Preferably, in step S1, the solvent is selected from one of propylene carbonate, toluene, cyclohexane, tetrahydrofuran, dichloroethane, dimethyl carbonate, n-octane, and n-hexane.
[0011] Preferably, in step S1, the phenolic compound is one of o-cresol, p-cresol, m-cresol, xylenol, 4-ethylphenol, benzyl acetate, guaiacol, phenol, and 2-methoxy-4-propylphenol.
[0012] Preferably, in step S2, the Metal / C is one of Pd / C, Ru / C, Rh / C, and Pt / C; the solid acid catalyst is one of H-Y, H-Beta, H-MOR, and Al-MCM-41; the mass ratio between the Metal / C and the solid acid catalyst is 1:(0.8 - 1.2).
[0013] Preferably, in step S2, the mass ratio between the catalyst dosage and the alkylation product prepared in step S1 is (0.01 - 0.3):1; the substrate concentration is 0.01 - 1 mol / L.
[0014] Preferably, in step S2, the hydrodeoxygenation reaction is carried out in a batch reactor; the temperature is 160 - 220 °C, the reaction time is 6 - 14 h, and the hydrogen pressure is 3 - 5 MPa.
[0015] Preferably, in step S2, the solvent used is selected from one or more of propylene carbonate, methanol, isopropanol, tridecane, toluene, tetrahydrofuran, N,N-dimethylformamide, n-hexane, ethyl acetate, and acetonitrile.
[0016] Compared with the prior art, the present invention has the following beneficial effects:
[0017] (1) The present invention uses phenolic compounds and eucalyptus oil as raw materials to effectively synthesize high-density aviation fuel through a two-step method. In the first step, phenolic compounds form a preliminary intermediate through a chemical reaction with eucalyptus oil, and then enter the second step. Through the action of a catalyst, the product structure is further optimized to achieve high density, high stability, and good combustion performance. The finally obtained fuel has a density greater than 0.90 g / mL, which gives it significant advantages in the field of aviation fuel. (2) The present invention innovatively uses biomass as a raw material and adopts a green and sustainable route, which not only reduces the dependence on petroleum resources but also avoids the environmental burden of traditional fossil energy. Biomass raw materials mainly come from plant materials and have the characteristics of renewability and low carbon emissions. During the entire synthesis process, no harmful waste gas or toxic by-product is generated, which conforms to the modern environmental protection concept. Through the development of this new green route, the production cost of aviation fuel can be effectively reduced. Description of the Drawings
[0018] Figure 1 . GC spectrum of the alkylation addition product with phenol and eucalyptus oil as raw materials in Example 24;
[0019] Figure 2 . MS spectrum of the alkylation addition product with phenol and eucalyptus oil as raw materials in Example 24;
[0020] Figure 3. Example 33 Using o-cresol and eucalyptus oil as raw materials, the 1 1H-NMR spectrum of the alkylated trimer addition product;
[0021] Figure 4 . Example 36 Using guaiacol and eucalyptus oil as raw materials, the GC spectrum of the alkylated addition product;
[0022] Figure 5 Example 36 Using guaiacol and eucalyptus oil as raw materials, the MS spectrum of the alkylated addition product;
[0023] Figure 6 . Example 40 Using 2-methoxy-4-propylphenol and eucalyptus oil as raw materials, the GC spectrum of the alkylated addition product;
[0024] Figure 7 . Example 45 Using phenol and eucalyptus oil as raw materials, the GC spectrum of hydrodeoxygenation of aviation fuel precursor;
[0025] Figure 8 . Example 45 Using phenol and eucalyptus oil as raw materials, the MS spectrum of hydrodeoxygenation of aviation fuel precursor. Detailed implementation manners
[0026] The present invention will be further described in detail below in conjunction with examples.
[0027] In the following examples, unless otherwise specified, the reagents used can be purchased commercially or obtained in the manner reported in known literature.
[0028] Example
[0029] A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds, the specific steps are as follows:
[0030] S1. Under the catalysis of 10 g of acid catalyst (10% of the mass of eucalyptus oil), add phenolic compound (7 mmol, 0.712 g) and eucalyptus oil (7 mmol, 1.078 g) to 1 mL of solvent, and at 60-160 °C, the eucalyptus oil is first dehydrated to form terpene compounds and then undergoes an alkylation reaction with the phenolic compound for 9-21 h to obtain an alkylated product with a bicyclic structure and a tricyclic structure;
[0031] S2. Add (0.3 g, 1 mmol) of the alkylated product prepared in step S1 to 10 mL of solvent, and under the co-catalysis of 30 mg of Metal / C and a solid acid catalyst (the mass ratio between Metal / C and the solid acid catalyst is 1:1), react at 160-220 °C and a hydrogen pressure of 3.5 MPa for 6-14 h to carry out hydrodeoxygenation to produce high-density aviation fuel.
[0032] Examples 1-44 are different in terms of phenolic compounds, catalysts, reaction temperatures, solvents, and reaction times in step S1. The specific parameters are shown in Table 1 below:
[0033] Table 1. Effects of phenolic compounds, catalysts, temperature, solvent, and time on the alkylation reaction
[0034]
[0035]
[0036] As can be seen from the results in Table 1, the catalysts HPW / SiO 2 , T-62MP, D600, D750, and MCM-41 showed good catalytic performance in the alkylation reaction of eucalyptus oil with phenolic compounds and achieved above-average yields. Among them, MCM-41 had the best catalytic performance, and the yield of the dimer product reached 96% after reacting at 120 °C for 15 h. Through the screening of different solvents, it was found that toluene, n-hexane, and propylene carbonate had relatively good effects on this reaction. However, considering environmental friendliness, n-hexane was selected as the solvent. Through the screening of different reaction times, it was found that extending the time did not increase the product yield. The yield of the dimer product was 93% after reacting for 21 h, which was not much different from the result of reacting for 15 h. At the same time, it was found that high yields could be achieved for the alkylation reactions of other phenolic compounds.
[0037] Since the service life of the catalyst needs to be investigated in practical applications, under the catalytic action of 0.7 mmol of MCM-41, phenol (7 mmol, 0.712 g) and eucalyptus oil (7 mmol, 1.078 g) were added to 1 mL of solvent. Using n-hexane as the solvent, the reaction was carried out at 120 °C for 15 h to study the recycling of MCM-41. After the first reaction, the product and the catalyst would automatically separate into layers. The upper layer was the product, and the lower layer was the catalyst. The product was separated, and the next cycle was continued. As can be seen from the results in Table 2, the yield did not change significantly after MCM-41 was recycled four times, indicating that this reaction system could be reused.
[0038] Table 2. Recycling experiment of MCM-41
[0039]
[0040] The GC chromatogram of the alkylation product prepared in Example 24 is as Figure 1As shown, the injection port temperature of the gas chromatography was set at 280 °C, the initial column oven temperature was set at 60 °C, the heating rate was 15 °C / min, and it was heated to 310 °C and held for 5 min. It can be seen from the GC chart that under the catalysis of the MCM-41 catalyst, the substance eluting at 11 - 14 min is the alkylated dimer product, and the substance eluting at 18 - 20 min is the alkylated trimer product.
[0041] The MS spectrum of the alkylated product prepared in Example 24 is as Figure 2 shown. It can be seen from the figure that the maximum mass-to-charge ratio of the molecular ion peak of this substance is m / z = 230, while the molecular weight of the eucalyptus oil isomerization dehydration product is 136, and the theoretical molecular weight of the phenol compound is 94. Therefore, this product is the target alkylated precursor.
[0042] The 1 1H-NMR spectrum of the alkylated trimer addition product prepared in Example 33 is as Figure 3 shown. 1HNMR(600MHz,CDCl3)δ7.20–7.10(m,1H),7.08–7.02(m,1H),7.01–6.91(m,1H),6.91–6.84(m,1H),6.78–6.64(m,2H),5.05–4.90(m,2H),2.27(d,J=7.2Hz,6H),2.05–1.40(m,8H),1.34(s,1H),1.26(s,3H),1.20–1.02(m,2H),0.87(d,J=7.0Hz,1H),0.79(d,J=6.9Hz,1H),0.66(d,J=6.4Hz,2H).
[0043] The GC spectrum of the alkylated product prepared in Example 36 is as Figure 4 shown. The injection port temperature of the gas chromatography was set at 280 °C, the initial column oven temperature was set at 60 °C, the heating rate was 15 °C / min, and it was heated to 310 °C and held for 5 min. It can be seen from the GC chart that under the catalysis of the MCM-41 catalyst, the substance eluting at 13 - 14 min is the alkylated dimer product.
[0044] The MS spectrum of the alkylated product prepared in Example 36 is as Figure 5 shown. It can be seen from the figure that the maximum mass-to-charge ratio of the molecular ion peak of this substance is m / z = 260, while the molecular weight of the eucalyptus oil isomerization dehydration product is 136, and the theoretical molecular weight of the guaiacol compound is 124. Therefore, this product is the target alkylated precursor.
[0045] The GC spectrum of the alkylated product prepared in Example 40 is as Figure 6As shown in the figure, the inlet temperature of the gas chromatography was set at 280 °C, the initial temperature of the column oven was set at 60 °C, the heating rate was 15 °C / min, and it was heated to 310 °C and held for 5 min. It can be seen from the GC chart that under the catalysis of the MCM-41 catalyst, the substances eluting at 13 - 16 min were the alkylation dimmer product of 2-methoxy-4-propylphenol and eucalyptol.
[0046] Examples 45 - 70 involved hydrodeoxygenation of the alkylation products obtained in Example 24, with the differences being the catalysts, reaction temperatures, solvents, and reaction times in step S2. The specific parameters are shown in Table 3 below:
[0047] Table 3. Effects of catalysts, temperature, solvent, and time on the hydrogenation reaction
[0048]
[0049]
[0050] As can be seen from the results in Table 3, the hydrogenation capabilities of different metal catalysts vary. Among them, metals Rh and Pd exhibited relatively good activities. During the screening of solvents, it was found that both toluene and n-hexane had good effects. However, since n-hexane also had a good effect in the alkylation reaction, n-hexane was used as the hydrogenation solvent. When screening the temperature for the hydrogenation reaction using n-hexane as the solvent, it was found that the yield was relatively high at 180 °C. Therefore, the optimal conditions for the hydrogenation reaction were obtained.
[0051] To explore the service life of the catalyst in practical applications, the recycling of Pd / C + H-Y was studied under the conditions of using n-hexane as the solvent and reacting at 180 °C for 10 h. As can be seen from the results in Table 4, there was no obvious change in the yield after recycling Pd / C + H-Y four times, indicating that this reaction system can be reused.
[0052] Table 4. Hydrodeoxygenation recycling experiments
[0053]
[0054] The GC chromatogram of the hydrogenation product prepared in Example 45 is as Figure 7 shown, and the MS chromatogram is as Figure 8 shown. It can be seen from the figures that the maximum mass-to-charge ratio of the molecular ion peak of this substance is m / z = 222, which is the molecular weight of the product obtained after hydrodeoxygenation of the alkylation product. The inlet temperature of the gas chromatography was set at 280 °C, the initial temperature of the column oven was set at 60 °C, the heating rate was 15 °C / min, and it was heated to 310 °C and held for 5 min. That is, the peak of the target biomass high-density fuel appeared at 11 - 13 min, and the peak of the hydrodeoxygenation product of the alkylation trimer appeared around 16 min.
[0055] The biomass high-density fuel obtained in Example 45 was compared with traditional petroleum-based fuels (JP-10, RJ-4, RJ-4-I, RJ-5, RJ-7) in terms of properties. It was found that while maintaining key properties such as density, calorific value, and freezing point, the difficulty and cost of synthesis were significantly reduced.
[0056] Table 5. Comparison of the properties of different fuels
[0057]
[0058] As can be seen from Table 5, through a two-step method, high-density aviation fuel can be prepared from eucalyptus oil. The density of the prepared high-density aviation fuel is 0.931 g / cm 3 , the calorific value is 41.3 MJ / Kg, and the freezing point is -60 °C. It is an aviation fuel with relatively excellent performance. The entire route uses biomass as the raw material, which is a new type of green and environmentally friendly route and does not produce harmful substances.
[0059] The above is only a specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention shall be covered by the protection scope of the present invention.
Claims
1. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds, characterized in that: The specific steps are: S1. Under the catalytic action of an acid catalyst, eucalyptus oil and a phenolic compound are added to a solvent in a molar ratio of 1:(0.6-1.0), and the eucalyptus oil first undergoes an isomerization reaction, and then dehydrates and undergoes an alkylation reaction with the phenolic compound to obtain an alkylated product having a bicyclic structure and a tricyclic structure; S2. Add the alkylation product prepared in step S1 into a solvent, and perform hydrodeoxygenation under the co-catalysis of Metal / C and a solid acid catalyst to generate a high-density aviation fuel.
2. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S1, the acid catalyst is one or more of p-toluenesulfonic acid, SBA-15, SF resin, T-62MP, Amberlyst15, Al-MCM-41, MCM-41, HPW / SiO2, HPW / MCM-41, D600, CD750, CD250, and SO4 / ZrO2-TiO2.
3. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S1, the mass of the acid catalyst is 10% of the mass of the eucalyptus oil; the reaction temperature is 60-160° C., the reaction time is 9-21 h; and the substrate concentration is 10-15 mol / L.
4. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S1, the solvent is selected from one of propylene carbonate, toluene, cyclohexane, tetrahydrofuran, ethylene dichloride, dimethyl carbonate, n-octane and n-hexane.
5. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S1, the phenolic compound is one of o-methylphenol, p-methylphenol, m-methylphenol, xylenol, 4-ethylphenol, benzyl acetate, guaiacol, phenol, and 2-methoxy-4-propylphenol.
6. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S2, the Metal / C is one of Pd / C, Ru / C, Rh / C, and Pt / C; the solid acid catalyst is one of HY, H-Beta, H-MOR, and Al-MCM-41; and the mass ratio between the Metal / C and the solid acid catalyst is 1:(0.8-1.2).
7. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S2, the mass ratio between the amount of catalyst used and the alkylation product prepared in step S1 is (0.01-0.3):1; and the substrate concentration is 0.01-1 mol / L.
8. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S2, the hydrodeoxygenation reaction is carried out in a tank reactor; the temperature is 160-220°C, the reaction time is 6-14h, and the hydrogen pressure is 3-5MPa.
9. A method for preparing high-density aviation fuel from eucalyptus oil and phenolic compounds according to claim 1, characterized in that: In step S2, the solvent used is selected from one or more of propylene carbonate, methanol, isopropanol, tridecane, toluene, tetrahydrofuran, N,N-dimethylformamide, n-hexane, ethyl acetate, and acetonitrile.