A method for producing high-density aviation fuel from turpentine and phenolic compounds

Abstract

The application discloses a method for preparing high-density aviation fuel from turpentine and phenolic compounds, and specifically comprises the following steps: S1, under the catalysis of an acid, phenolic compounds and turpentine are added into a solvent to generate an alkylation reaction, and an alkylation product with a bicyclic structure and a tricyclic structure is obtained; and S2, the alkylation product prepared in the step S1 is added into a solvent, and under the catalysis of Metal / C and a solid acid catalyst, hydrogenation and deoxidization are carried out to generate high-density aviation fuel. The high-density aviation fuel is prepared from the phenolic compounds and the turpentine as raw materials by the two-step method, the yield is high, the density is greater than 0.90 g / mL, and the aviation kerosene alkane compound is excellent in performance. The biomass is used as the raw material, and the method is a novel and green route, and no harmful substances are generated.

Description

Technical Field

[0001] This invention relates to the field of organic compound synthesis technology, specifically to a method for preparing high-density aviation fuel from turpentine oil and phenolic compounds. Background Technology

[0002] High-density hydrocarbon fuels typically refer to artificially synthesized fuels with a density greater than 0.80 g / cm³. 3 Alkane fuels provide crucial propulsion for various aerospace vehicles, including missiles, rockets, and fighter jets, making them a key research focus in the propellant field. With the development of modern advanced technologies, improving the flight performance of aircraft (including high speed, long range, large payload, and high maneuverability) is essential, thus placing higher demands on their propulsion capabilities. Increasing fuel density and volumetric calorific value is a crucial way to enhance aircraft propulsion performance at low cost. The higher the calorific value of the fuel, the greater the energy released per unit volume during combustion, requiring a smaller fuel tank, which is more beneficial for improving aircraft performance. For an aircraft with a fixed fuel tank volume, higher fuel density allows for a larger fuel mass to be carried, resulting in a longer range. Furthermore, with a fixed total thrust, higher fuel density requires a smaller fuel tank, facilitating miniaturization and improving the aircraft's penetration capability and maneuverability.

[0003] Phenolic compounds have always played an important role in our production and daily life. For example, phenolic resins, which are widely used in production and daily life, are mainly derived from the condensation of phenolic compounds (such as cresol and xylenol) and formaldehyde, and have excellent 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). They all have irreplaceable roles. Similarly, from the perspective of saving resources and protecting the environment, using lignin phenolic platform compounds for catalytic conversion into polycyclic alkane fuels is a promising direction. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing high-density aviation fuel from turpentine oil and phenolic compounds. This method simplifies the preparation steps, increases the yield, and can produce high-performance high-density aviation fuel.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing high-density aviation fuel from turpentine oil and phenolic compounds, comprising the following steps:

[0006] S1. Under the catalysis of an acid catalyst, turpentine oil and phenolic compounds are added to a solvent at a molar ratio of 1:(0.8-1.2) to undergo an alkylation reaction, yielding alkylated products with bicyclic and tricyclic structures;

[0007] S2. The alkylated product obtained in step S1 is added to a solvent, and under the co-catalysis of Metal / C and a solid acid catalyst, it is subjected to hydrodeoxygenation to generate high-density aviation fuel.

[0008] Preferably, in step S1, the acid catalyst is one or more of p-toluenesulfonic acid, Nafion, T-62MP, Amberlyst15, Al-MCM-41, HPW / SiO2, HPW / MCM-41, D600, CD750, CD250, and SO4 / ZrO2-TiO2.

[0009] Preferably, in step S1, the ratio of the mass of the acid catalyst to the total mass of the phenolic compound and turpentine is (0.01-0.5):1; the reaction temperature is 60-160℃, the reaction time is 9-21h, and the substrate concentration is 10-15mol / 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-methylphenol, p-methylphenol, m-methylphenol, xylenol, 4-ethylphenol, benzyl acetate, guaiacol, and phenol.

[0012] Preferably, in step S2, the Metal / C is one of Pd / C, Ru / C, and Rh / 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).

[0013] Preferably, in step S2, the mass ratio between the amount of catalyst and the alkylation product prepared in step S1 is (0.01-0.3):1; and 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℃, the reaction time is 6-14h, and the hydrogen pressure is 3-5MPa.

[0015] Preferably, in step S2, the solvent used is selected from one or more of cyclohexane, 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) This invention uses phenolic compounds and turpentine as raw materials to efficiently synthesize high-density aviation fuel through a two-step method. In the first step, phenolic compounds react with turpentine to form a preliminary intermediate product. Then, in the second step, the product structure is further optimized through the action of a catalyst to achieve high density, high stability, and good combustion performance. The final fuel density is greater than 0.90 g / mL, which gives it a significant advantage in the field of aviation fuel.

[0018] (2) This invention innovatively uses biomass as a raw material, adopting a green and sustainable approach, which not only reduces dependence on petroleum resources but also avoids the environmental burden of traditional fossil fuels. The biomass raw material is mainly derived from plant materials, possessing the characteristics of renewability and low carbon emissions. No harmful waste gases or toxic byproducts are generated throughout the synthesis process, conforming to modern environmental protection concepts. The development of this novel green route can effectively reduce the production cost of aviation fuel. Attached Figure Description

[0019] Figure 1 Example 10: MS spectrum of alkylation dimerization addition product using phenol and turpentine as raw materials;

[0020] Figure 2 Example 21 MS spectrum of alkylation trimerization product using phenol and turpentine as raw materials;

[0021] Figure 3 Example 21: GC spectrum of alkylation addition product using phenol and turpentine as raw materials;

[0022] Figure 4 Example 21: Using phenol and turpentine as raw materials, the alkylation dimerization addition product... 1 H-NMR spectrum;

[0023] Figure 5 Example 21: Using phenol and turpentine as raw materials, the alkylation trimerization product... 1 H-NMR spectrum;

[0024] Figure 6 Example 21 uses phenol and turpentine as raw materials, with alkylation involving oxygen atoms in the reaction. 1 H-NMR spectrum;

[0025] Figure 7 Example 21 uses phenol and turpentine as raw materials, with alkylation involving oxygen atoms in the reaction. 13 C-NMR spectrum;

[0026] Figure 8 Example 30: Using o-methylphenol and turpentine as raw materials, the alkylation trimerization product... 1 H-NMR spectrum;

[0027] Figure 9 Example 30: Using o-methylphenol and turpentine as raw materials, the alkylation dimerization addition product... 1 H-NMR spectrum;

[0028] Figure 10 Example 31: Using p-methylphenol and turpentine as raw materials, the alkylation dimerization addition product... 1 H-NMR spectrum;

[0029] Figure 11 Example 41: GC spectrum of hydrodeoxygenation of aviation fuel precursor;

[0030] Figure 12 Example 41 MS spectrum of hydrogenated deoxygenated aviation fuel precursor. Detailed Implementation

[0031] The present invention will be further described in detail below with reference to the embodiments.

[0032] In the following examples, unless otherwise stated, all reagents used are commercially available or obtained in accordance with known literature.

[0033] Example

[0034] A method for preparing high-density aviation fuel from turpentine oil and phenolic compounds, comprising the following steps:

[0035] S1. Under the catalysis of 0.7 mmol acid catalyst, phenolic compound (7 mmol, 0.712 g) and turpentine oil (7 mmol, 0.952 g) were added to 1 mL solvent and alkylation reaction was carried out at 60-160 °C for 9-21 h to obtain alkylated products with bicyclic and tricyclic structures.

[0036] S2. Add (0.3 g, 1 mmol) of the alkylated product obtained in step S1 to 10 mL of solvent, and react at 160-220 °C and 3.5 MPa hydrogen pressure for 6-14 h under the co-catalysis of 30 mg Metal / C and solid acid catalyst (the mass ratio between Metal / C and solid acid catalyst is 1:1) to produce high-density aviation fuel.

[0037] The differences between Examples 1-36 lie in the phenolic compound, catalyst, reaction temperature, solvent, and reaction time in step S1. Specific parameters are shown in Table 1 below.

[0038] Table 1. Effects of phenolic compounds, catalysts, temperature, solvents, and time on alkylation reactions.

[0039]

[0040]

[0041] As shown in Table 1, the heterogeneous catalysts Amberlyst 15, CD750, D600, and Nafion exhibited good catalytic performance in the alkylation reaction of turpentine with phenolic compounds, achieving moderate to high yields. Nafion showed the best catalytic performance, achieving a 95% dimer product yield after 15 hours of reaction at 100°C. Screening of different solvents revealed that toluene, cyclohexane, and propylene carbonate had relatively good effects on this reaction; however, cyclohexane was chosen as the solvent from an environmental perspective. Screening of different reaction times showed that extending the reaction time did not increase the product yield; the dimer product yield was 93% after 21 hours of reaction, not significantly different from the result after 15 hours. Furthermore, high yields were achieved for the alkylation of other phenolic compounds.

[0042] Since catalyst lifespan needs to be considered in practical applications, phenol (7 mmol, 0.712 g) and turpentine oil (7 mmol, 0.952 g) were added to 1 mL of solvent using cyclohexane as the solvent and reacted at 100 °C for 15 h under the catalysis of 0.7 mmol Nafion to investigate the recycling of Nafion. After the first reaction, the product and catalyst automatically separated into layers, with the product on top and the catalyst on the bottom. The product was separated, and the next cycle was carried out. Table 2 shows that the yield did not change significantly after four cycles of Nafion, indicating that the reaction system is reusable.

[0043] Table 2. Nafion Cyclic Experiment

[0044]

[0045] The MS spectrum of the alkylated product obtained in Example 10 is as follows. Figure 1 As shown in the figure, the maximum mass-to-charge ratio (m / z) of the molecular ion peak of this substance is 230, while the molecular weight of turpentine is 136 and the theoretical molecular weight of phenolic compounds is 94. Therefore, this product is the target alkylation precursor.

[0046] The alkylated products obtained in Example 21 were separated by TLC or column chromatography to separate the dimer, trimer and products with different structures obtained by the polymerization reaction involving oxygen atoms. The specific structures were obtained by nuclear magnetic resonance hydrogen spectroscopy analysis.

[0047] The MS spectrum of the alkylated product obtained in Example 21 is shown below. Figure 2 As shown in the figure, the maximum mass-to-charge ratio (m / z) of the molecular ion peak of this substance is 324, while the molecular weight of turpentine is 136 and the theoretical molecular weight of phenolic compounds is 94. Therefore, this product is the target alkylation precursor.

[0048] The GC spectrum of the alkylated product obtained in Example 21 is shown below. Figure 3 As shown in the figure. The gas chromatography injection temperature was set to 280℃, the initial column oven temperature to 60℃, and the heating rate to 15℃ / min, reaching 310℃ and holding for 5 min. The GC chromatogram shows that, under the catalysis of Nafion catalyst, the product eluting at 11 min is the oxygen-atom-related product, the product eluting at 12–14 min is the alkylation dimer product, and the product eluting at 18–20 min is also the alkylation dimer product.

[0049] The alkylated dimerization addition product obtained in Example 21 1 H-NMR spectrum as shown Figure 4 shown. 1HNMR (600MHz, CDCl3) δ7.25–7.07(m,1H),6.93–6.63(m,2H),5.93–5.21(m,1H),2.85–1.51(m,7H),1.43–1.23(m,4H),1.22–0.65(m,7H).

[0050] The alkylated trimerization product obtained in Example 21 1 H-NMR spectrum as shown Figure 5 As shown. ¹H NMR (600MHz, CDCl₃) δ 0.86 (d, J = 6.9Hz, ¹H), 0.78 (d, J = 6.9Hz, ¹H), 0.65 (d, J = 6.4Hz, ¹H).

[0051] The alkylated dimerization addition product obtained in Example 21 1 H-NMR spectrum as shown Figure 6shown. 1HNMR (600MHz, CDCl3) δ7.50–6.61(m,5H),4.13–3.83(m,1H),1.89–1.84(m,1H),1.81–1.74(m,2H),1.68–1. 63(m,1H),1.40–1.34(m,1H),1.21–1.14(m,2H),1.08(d,J=17.0Hz,3H),1.01(d,J=5.4Hz,3H),0.90(s,3H).

[0052] The alkylated dimerization addition product obtained in Example 21 13 C-NMR spectrum as shown Figure 7 As shown. 13C NMR (151MHz, CDCl3) δ 157.98, 129.30, 119.97, 115.39, 84.40, 49.19, 47.02, 45.31, 39.54, 34.25, 27.41, 20.35, 20.14, 11.82.

[0053] The alkylated products obtained in Example 30 were separated by TLC or column chromatography to separate the different structures of the dimer and trimer products, and their specific structures were obtained by nuclear magnetic resonance hydrogen spectroscopy analysis.

[0054] The 1H-NMR spectrum of the alkylated trimerization product obtained in Example 30 is as follows: Figure 8 shown. 1HNMR (600MHz, CDCl3) δ7.20–7.10(m,1H),7.05(d,J=26.2Hz,1H),6.98(d,J=2.2Hz,1H),6.90(d,J=2.2Hz,1H),6.78–6.64(m,2H),5.05–4.90(m ,2H),2.32–2.23(m,6H),1.89(s,8H),1.34(s,1H),1.26(s,3H),1.13(s, 2H), 0.87 (d, J = 7.0Hz, 1H), 0.79 (d, J = 6.9Hz, 1H), 0.66 (d, J = 6.4Hz, 2H).

[0055] The 1H-NMR spectrum of the alkylated dimerization addition product obtained in Example 30 is shown below. Figure 9 As shown. ¹H NMR (600MHz, CDCl₃) δ 7.03–6.82 (m, ¹H), 6.77–6.62 (m, ¹H), 5.49–5.03 (m, ¹H), 2.83–2.06 (m, 5H), 1.98–1.42 (m, 5H), 1.39–0.48 (m, ¹²H).

[0056] The 1H-NMR spectrum of the alkylated dimerization addition product obtained in Example 31 is shown below. Figure 10 As shown. ¹H NMR (600MHz, CDCl₃) δ 7.25–7.07 (m, ¹H), 6.83–6.57 (m, 2H), 5.08–4.64 (m, ¹H), 2.44–2.25 (m, 4H), 1.96–1.27 (m, 8H), 1.20–0.83 (m, 8H).

[0057] Examples 41-63 involve the hydrodeoxygenation of the alkylation product obtained in Example 21, differing only in the catalyst, reaction temperature, solvent, and reaction time in step S2. Specific parameters are shown in Table 3 below.

[0058] Table 3. Effects of catalyst, temperature, solvent, and time on hydrogenation reaction

[0059]

[0060] Table 3 shows that different metal catalysts have varying hydrogenation capabilities. Rh and Pd exhibit the best activity. Solvent selection revealed that both toluene and cyclohexane showed good results, but because cyclohexane still performs well in alkylation reactions, it was chosen as the hydrogenation solvent. Further selection of the optimal temperature for hydrogenation using cyclohexane as the solvent showed that a higher yield was obtained at 180℃, thus establishing the optimal conditions for the hydrogenation reaction.

[0061] Table 4. Hydrogenation Deoxygenation Cycle Experiment

[0062]

[0063] The MS spectrum of the hydrogenation product obtained in Example 41 is as follows. Figure 11 As shown, the GC spectrum is as follows Figure 12 As shown in the figure, the maximum mass-to-charge ratio (m / z) of the molecular ion peak of this substance is 222, which is the molecular weight of the product obtained after hydrogenation and deoxygenation of the alkylation product. The gas chromatography injection temperature was set to 280℃, the initial column oven temperature to 60℃, and the heating rate to 15℃ / min, reaching 310℃ and holding for 5 min. That is, the peak of the target biomass high-density fuel appeared at approximately 11 min, and the peak of the hydrogenation and deoxygenation product of the alkylation trimer appeared at approximately 15 min.

[0064] The properties of the high-density biomass fuel obtained in Example 41 were compared with those of traditional petroleum-based fuels (JP-10, RJ-4, RJ-4-I, RJ-5, RJ-7). It was found that while maintaining key properties such as density, calorific value, and freezing point, the synthesis difficulty and cost were greatly reduced.

[0065] Table 5. Comparison of performance of different fuels

[0066]

[0067] As shown in Table 5, a two-step method can be used to prepare high-density aviation fuel from turpentine oil, and the density of the obtained high-density aviation fuel is 0.943 g / cm³. 3 With a calorific value of 41.5 MJ / Kg and a freezing point of -60℃, it is a high-performance aviation fuel. The entire route uses biomass as raw material, making it a new type of green and environmentally friendly route that does not produce harmful substances.

[0068] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions, and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention, and within the spirit and principles of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A method for producing high-density aviation fuel from turpentine and phenolic compounds, characterized by, The specific steps are as follows: S1. Under the catalysis of an acid catalyst, turpentine oil and phenolic compounds are added to a solvent at a molar ratio of 1:(0.8-1.2) to undergo an alkylation reaction, yielding alkylated products with bicyclic and tricyclic structures; the phenolic compounds are one of o-methylphenol, p-methylphenol, m-methylphenol, 4-ethylphenol, guaiacol, and phenol; the acid catalyst is one or more of p-toluenesulfonic acid, Nafion, T-62MP, Amberlyst15, Al-MCM-41, HPW / SiO2, HPW / MCM-41, and SO4 / ZrO2-TiO2; the mass ratio of the acid catalyst to the total mass of the phenolic compounds and turpentine oil is (0.01-0.5):1; the reaction temperature is 60-160℃, the reaction time is 9-21h; and the substrate concentration is 10-15%. mol / L; the solvent is selected from one of propylene carbonate, toluene, cyclohexane, tetrahydrofuran, dichloroethane, dimethyl carbonate, n-octane, and n-hexane; S2. The alkylated product obtained in step S1 is added to a solvent, and under the co-catalysis of Metal / C and a solid acid catalyst, hydrodeoxygenation is carried out to generate high-density aviation fuel; wherein Metal / C is one of Pd / C, Ru / C, and Rh / C. The solid acid catalyst is one of HY, H-MOR, and Al-MCM-41; the mass ratio between Metal / C and the solid acid catalyst is 1:(0.8-1.2).

2. A method of preparing high-density aviation fuel from turpentine and phenolic compounds according to claim 1, characterized in that, In step S2, the mass ratio between the amount of catalyst and the alkylation product prepared in step S1 is (0.01-0.3):1; the substrate concentration is 0.01-1 mol / L.

3. The method for preparing high-density aviation fuel from turpentine oil and phenolic compounds according to claim 1, characterized in that, In step S2, the hydrodeoxygenation reaction is carried out in a batch reactor at a temperature of 160-220℃ for 6-14 h and a hydrogen pressure of 3-5 MPa.

4. The method for preparing high-density aviation fuel from turpentine oil and phenolic compounds according to claim 1, characterized in that, In step S2, the solvent used is selected from one or more of cyclohexane, propylene carbonate, methanol, isopropanol, tridecane, toluene, tetrahydrofuran, N,N-dimethylformamide, n-hexane, ethyl acetate, and acetonitrile.

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