Method for preparing high-energy-density fuel from benzaldehyde compound and phenol compound

Abstract

The invention discloses a method for preparing a high-energy-density fuel from a benzaldehyde compound and a phenol compound, which comprises the following specific steps of: 1, under the condition of no solvent, carrying out condensation reaction on the benzaldehyde compound and the phenol compound under the catalysis of an acid catalyst to generate a bisphenol or triphenol product; and 2, carrying out hydrodeoxygenation (HDO) on the bisphenol or triphenol product as a high-energy density fuel precursor under respective catalysis of Metal / C and a solid acid catalyst to obtain the high-energy density fuel. According to the method, green renewable resources are used as initial raw materials, efficient cyclic utilization of the catalyst is achieved through the advantages of few steps and easy operation and the green and environment-friendly characteristics, and the whole process is economical and environment-friendly; the density of the prepared high-energy-density fuel is greater than 0.90 g / cm < 3 >, the calorific value is greater than 40MJ / L, and the performance is comparable with that of a petroleum-based high-energy-density fuel.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic synthesis, and particularly relates to a method for preparing high-energy-density fuel from benzaldehyde compounds and phenol compounds. BACKGROUND

[0002] High-energy-density fuel is mainly applied to the fields of aerospace and national defense, and has higher requirements for the performance of fuel, and needs the fuel to provide more propulsion power under the condition of a certain fuel tank volume, that is, has higher density and volumetric heat value, and can be safely used under lower temperature environment and conditions. Lignin is an amorphous polymer composed of phenylpropane units through carbon-carbon bonds and carbon ether bonds, and the structural units contain active groups such as alcohol hydroxyl, phenolic hydroxyl, carbon-carbon double bond and carbon-oxygen double bond. Therefore, the preparation of high-density fuel from lignin derivatives mainly constructs the expected structure by modifying the structure under the action of external force through the rich active functional groups in the lignin unit. These structures are the precursors of fuel, and the high-density fuel is obtained by subsequent hydrogenation and deoxygenation.

[0003] Benzaldehyde is a lignin platform compound, which can be obtained by photocatalytic selective oxidation of beta-1 lignin model compounds (ACSCatalysis, 2017, 7(5): 3344-3348). Phenol is the simplest lignin model compound (Chemical Engineering Journal, 2020, 386: 121348; Acs Catalysis, 2018, 8(8): 6837-6843). At present, there are many reports on biomass fuel. Overall, the density and heat value of most biomass fuels cannot meet the performance requirements of aerospace and military fuels. Therefore, in the design of fuel precursors, a polycyclic structure is introduced, and it is hoped that the density of the fuel will increase with three or more rings in the molecule. In addition, these rings need to have a certain ring strain, so as to increase the volumetric heat value of the fuel. SUMMARY

[0004] The purpose of the present application is to provide a method for preparing high-energy-density fuel from benzaldehyde compounds and phenol compounds, which has the characteristics of simple steps, easy operation, efficient recycling of catalysts, and can prepare high-energy-density fuel.

[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: a method for preparing high-energy-density fuel from benzaldehyde compounds and phenol compounds, comprising the following steps:

[0006] The first step, under the condition of no solvent, the condensation reaction of benzaldehyde compounds and phenol compounds is carried out under the catalysis of an acidic catalyst to generate biphenol or triphenol products; the benzaldehyde compounds are benzaldehyde or vanillin; the phenol compounds are phenol or guaiacol; the structural formula of the biphenol or triphenol products is

[0007]

[0008] one of the following formulas:

[0009] The second step, the biphenol or triphenol products are used as high-energy density fuel precursors, and the hydrogenation and deoxygenation reaction is carried out under the catalysis of Metal / C and a solid acidic catalyst to obtain high-energy density fuels; the structural formula of the high-energy density fuels is one of the following formulas:

[0010] Preferably, in the first step, the molar ratio of the phenol compounds and the benzaldehyde compounds is 2:1 to 6:1.

[0011] Preferably, in the first step, the acidic catalyst is selected from one of the following catalysts: phosphotungstic acid, phosphomolybdic acid, an acidic resin, a molecular sieve, a metal oxide compound, a sulfate-modified acidic resin, a molecular sieve, the metal oxide compound is Cs-HPW / SiO2, the sulfate-modification is SO4 2- / ZrO2-TiO2, the acidic resin is one of Amberlyst-15, Nafion, T-62MP, D600 and CD750, the molecular sieve is one of H-beta, H-Y, H-ZSM5 and Al-MCM-41; the mass of the acidic catalyst is 5-25wt% of the mass of the benzaldehyde.

[0012] Preferably, in the first step, the reaction temperature is 60-140 DEG C, and the reaction time is 2-10h.

[0013] Preferably, in the second step, the Metal / C is one or more than two of Ni / C, Pd / C, Pt / C, Ru / C and Rh / C, and the solid acid catalyst is one or more than two of USY, MCM-41, H-Y, H-ZSM-5, H-Beta and H-MOR; wherein the mass of the Metal / C and the mass of the solid acidic catalyst are 5% and 10% of the mass of the biphenol product respectively.

[0014] Preferably, in the second step, the hydrogenation and deoxygenation reaction is carried out in a tank reactor; the reaction temperature is 140-200 DEG C, the reaction time is 6-14h, and the hydrogen pressure is 1-4MPa.

[0015] Compared with the prior art, the present application has the following beneficial effects: ​

[0016] 1. The present application can completely realize the preparation of high energy density fuels from benzaldehyde compounds and phenolic compounds by a two-step method, which have a density greater than 0.90 g / cm 3 , a heat value greater than 40 MJ / L, and a performance comparable to petroleum-based high energy density.

[0017] 2. The entire route uses lignin derivatives benzaldehyde and phenolic compounds as raw materials, which are green in origin and do not produce additional harmful substances.

[0018] 3. The catalyst has certain water resistance, applicability and recycling ability. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 . GC spectrum of bisphenol product of Example 19;

[0020] Figure 2 . H-NMR spectrum of bisphenol product of Example 19 obtained from benzaldehyde and phenol as raw materials; 1

[0021] Figure 3 . C-NMR spectrum of bisphenol product of Example 19 obtained from benzaldehyde and phenol as raw materials; 13

[0022] Figure 4 . H-NMR spectrum of bisphenol product of Example 26 obtained from benzaldehyde and guaiacol as raw materials; 1

[0023] Figure 5 . C-NMR spectrum of bisphenol product of Example 26 obtained from benzaldehyde and guaiacol as raw materials; 13

[0024] Figure 6 . H-NMR spectrum of triphenol product of Example 27 obtained from vanillin and guaiacol as raw materials; 1

[0025] Figure 7 . C-NMR spectrum of triphenol product of Example 27 obtained from vanillin and guaiacol as raw materials; 13

[0026] Figure 8 . H-NMR spectrum of triphenol product of Example 28 obtained from vanillin and phenol as raw materials; 1

[0027] Figure 9 . C-NMR spectrum of triphenol product of Example 28 obtained from vanillin and phenol as raw materials; 13

[0028] ​​​​​​​​Figure 10 Example 36C 19 GC spectra of hydrodeoxygenation of high energy density fuel precursors;

[0029] Figure 11 Example 36C 19 MS spectra of hydrodeoxygenation of high energy density fuel precursors;

[0030] Figure 12 Example 36C 19 H-NMR spectra of hydrodeoxygenation of high energy density fuel precursors; 1 H-NMR spectra of hydrodeoxygenation of high energy density fuel precursors;

[0031] Figure 13 Example 36C 19 C-NMR spectra of hydrodeoxygenation of high energy density fuel precursors; 13 C-NMR spectra of hydrodeoxygenation of high energy density fuel precursors. DETAILED DESCRIPTION

[0032] The present application will be further described in conjunction with the drawings and specific examples.

[0033] A method for preparing high energy density fuel from benzaldehyde compounds and phenol compounds, comprising the following steps:

[0034] In the first step, phenol 2 or guaiacol 2 and an acidic catalyst were added into a 35 mL sealed tube under solvent-free condition, followed by the addition of benzaldehyde 1 or vanillin 1 (0.53 g, 5 mmol) and reaction at a temperature of 60-140 °C for 2-10 h;

[0035]

[0036] In the second step, the bisphenol product (0.276 g, 1 mmol), Pd / C (13.8 mg) and isopropanol (2.0 mL) were sequentially added into a 50 mL high-pressure reactor. The reaction was stirred at a hydrogen pressure of 1.0-4.0 MPa at 140-180 °C for 2-5 h. After cooling to room temperature, the isopropanol was evaporated, and H-Y molecular sieves (27.6 mg) and n-hexane (5 mL) were added, and the stirring was continued under hydrogen (2.0 MPa) and at a temperature of 140-200 °C for 4-9 h; the hydrogenation and deoxygenation reaction obtained high energy density fuel 5.

[0037] Examples 1-25

[0038] Examples 1-25 differ in the benzaldehyde compound, phenol compound, acidic catalyst and amount used, phenol compound / benzaldehyde compound molar ratio, reaction temperature, and reaction time in the first step, and the specific details are shown in Table 1 below:

[0039] Table 1. Effects of benzaldehyde compounds, phenolic compounds, type and amount of acidic catalyst, molar ratio of phenolic compounds to benzaldehyde compounds, reaction temperature, and reaction time on the phenolic condensation reaction.

[0040]

[0041]

[0042]

[0043] As shown in Table 1, the homogeneous heteropolyacids phosphotungstic acid (HPW) and phosphomolybdic acid (HPMo) were first considered. Under HPMo catalysis, the overall product yield was 91%. Next, commercially available solid acid catalysts Amberlyst-15, Nafion, and T-62MP were tried, all exhibiting excellent catalytic activity with overall product yields exceeding 87%. D600, an acrylic resin solid acid, yielded 67% overall. Although its large pore size facilitates molecule entry and exit, its acidity is relatively weak. Furthermore, the polymeric solid acid catalyst CD750, with its strong acidity and large pore size, showed that it compensated for the weak acidity of D600, further improving the overall product yield. Considering factors such as catalyst price and water resistance, Nafion was selected as the most suitable catalyst. The phenol-formaldehyde condensation reaction of benzaldehyde and phenol under Nafion catalysis achieved a high overall yield of 89% for bisphenol products under optimal reaction conditions: benzaldehyde (0.53 g, 5 mmol), phenol (1.88 g, 20 mmol), Nafion (15 wt%), temperature (80 °C), and reaction time (8 h). Furthermore, as shown in Table 1, the phenol-formaldehyde condensation reactions combining representative compounds such as vanillin, benzaldehyde, guaiacol, and phenol all specifically reacted to generate bisphenol or triphenol products under the Nafion catalysis system, achieving separation yields of 66-92%. This verifies the universality of the Nafion catalysis system, enabling selective generation of target products in complex reactions and reducing side reactions.

[0044] Example 19: GC spectrum of the condensed bisphenol product is shown below. Figure 1 As shown, the bisphenol product synthesized in Example 19 1 H-NMR spectrum as shown Figure 2 As shown, 13 C-NMR spectrum as shown Figure 3 As shown. The bisphenol product synthesized in Example 26. 1 H-NMR spectrum as shown Figure 4 As shown, 13 C-NMR spectrum as shown Figure 5The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. 1 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. Figure 6 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. 13 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. Figure 7 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. 1 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. Figure 8 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. 13 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below. Figure 9 The H-NMR spectrum of the triphenol product synthesized in Example 27 is shown below.

[0045] 1 H NMR (400 MHz, DMSO-d6) δ 9.26 (s, 2H), 7.26 (dd, J = 8.2, 6.9 Hz, 2H), 7.20 - 7.12 (m, 1H), 7.11 - 7.05 (m, 2H), 6.94 - 6.86 (m, 4H), 6.74 - 6.67 (m, 4H), 5.36 (s, 1H).

[0046] 13 C NMR (100 MHz, DMSO-d6) δ 155.58, 145.07, 134.66, 129.90, 128.93, 128.18, 125.90, 115.03, 53.86.

[0047] 1 H NMR (400 MHz, DMSO-d6) δ 8.83 (s, 1H), 7.27 (t, J = 7.5 Hz, 2H), 7.22 - 7.14 (m, 1H), 7.13 - 7.06 (m, 2H), 6.76 - 6.66 (m, 4H), 6.46 (dd, J = 8.2, 2.0 Hz, 2H), 5.37 (s, 1H), 3.64 (s, 6H).

[0048] 8.2, 2.0 Hz, 2H), 5.37 (s, 1H), 3.64 (s, 6H).

[0049] 13 C NMR (100 MHz, DMSO-d6) δ 147.30, 144.87, 143.25, 135.26, 128.92, 128.17, 125.98, 121.35, 115.14, 113.40, 55.62, 55.11.

[0050] 1H NMR (400 MHz, DMSO-d6) δ 8.77 (s, 3H), 6.87 - 6.59 (m, 6H), 6.46 (dd, J = 8.2, 2.1 Hz, 3H), 5.25 (s, 1H), 3.65 (s, 9H).

[0051] 13 C NMR (100 MHz, DMSO-d6) δ 147.25, 144.71, 135.77, 121.23, 115.14, 113.29, 55.60.

[0052] 1 H NMR (400 MHz, DMSO-d6) δ 9.20 (s, 2H), 8.76 (s, 1H), 6.87 (dd, J = 8.4, 6.1 Hz, 4H), 6.77 - 6.62 (m, 6H), 6.44 (td, J = 7.8, 2.1 Hz, 1H), 5.23 (s, 1H), 3.64 (s, 3H).

[0053] 13 C NMR (100 MHz, DMSO-d6) δ 155.42, 147.28, 144.69, 135.96, 135.22, 129.79, 121.23, 115.15, 114.92, 112.79, 55.58, 54.03.

[0054] Examples 29-33

[0055] To meet the actual use requirements, the reusability of Nafion catalyst was also verified. Phenol (1.88 g, 20 mmol) and benzaldehyde (0.53 g, 5 mmol) were reacted at 80 °C for 8 h under the catalysis of 80 mg of Nafion, and the recycling use of Nafion was studied. After the end of the first reaction, the product and the catalyst were automatically layered, 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 Table 2, after five cycles, the total yield of the product remained above 80%, and there was no obvious decrease in catalytic activity, indicating that the catalyst had good reusability stability.

[0056] Table 2. Change of total yield of bisphenol product with recycling number of Nafion catalyst

[0057]

[0058] Examples 34-44

[0059] Examples 34-44 are hydrogenation-deoxidation of the condensation product of Example 19, the difference is the catalyst, reaction temperature in the second step, the specific parameters are shown in Table 3:

[0060] Table 3. The effect of reaction temperature, system pressure, reaction time on the hydrogenation-deoxidation reaction of fuel precursor

[0061]

[0062]

[0063] From Table 3, it can be seen that the hydrogenation reaction is successfully completed at 180°C, 4h in a hydrogen atmosphere with 5wt% Pd / C as the hydrogenation catalyst, isopropanol as the solvent, and fuel 5 is obtained. After the hydrogenation is completed, the solvent isopropanol is evaporated at 85°C in a metal bath, and H-Y is used as the deoxidation catalyst for condition optimization. When the initial temperature is 140°C, the yield of fuel 5 is 59%. As the temperature continues to rise to 180°C, the fuel yield increases to 92%, and as the temperature continues to rise, the product yield slightly decreases, and 180°C is used as the deoxidation reaction temperature. The system hydrogen pressure also plays an important role in the reaction, and when the system H2 pressure is 2MPa, the fuel yield is the largest. At the same time, it is found that prolonging the reaction time can effectively improve the yield of fuel 5, and therefore, in a H2(2MPa) atmosphere, the deoxidation reaction is completed at 180°C for 12h, and the yield of fuel 5 is 92%.

[0064] The GC spectrum of hydrogenation-deoxidation product 5 of Example 36 is shown in Figure 10 , the MS spectrum is shown in 1 , the H-NMR spectrum is shown in Figure 12 , and the C-NMR spectrum is shown in 13 . Figure 13

[0065] Table 4. Comparison of the performance of biomass fuel and petroleum-based high-energy density fuel

[0066]

[0067] From Table 4, it can be seen that high-energy density fuel is prepared from lignin derivatives benzaldehyde and phenol, and the obtained C 19 The density of the tricyclic fuel is 0.944g / cm 3 , the heat value reaches 45.89MJ / L, the freezing point is -49°C, and the kinematic viscosity is 909.1cSt. The comprehensive performance of the obtained fuel meets the performance requirements of high-energy density fuel, and is better than that of some petroleum-based fuels, and is comparable to the comprehensive performance of JP-10 fuel.

[0068] ​The above merely illustrates the specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any modification, equivalent replacement and improvement within the technical range disclosed by the present application and within the spirit and principle of the present application should be covered within the protection scope of the present application.

Claims

1. A method for preparing high-energy-density fuel from benzaldehyde compounds and phenol compounds, characterized in that, Includes the following steps: The first step involves a solvent-free reaction in which benzaldehyde compounds undergo a condensation reaction with phenolic compounds under the catalysis of an acidic catalyst to generate bisphenol or triphenol products. The benzaldehyde compounds are benzaldehyde or vanillin; the phenolic compounds are phenol or guaiacol; and the structural formula of the bisphenol or triphenol products is as follows: One of them; The second step involves using bisphenol or triphenol products as high-energy-density fuel precursors, which undergo hydrogenation and deoxygenation reactions under the catalysis of Metal / C and solid acid catalysts, respectively, to obtain high-energy-density fuel; the structural formula of the high-energy-density fuel is as follows. One of them.

2. A method for preparing high-energy-density fuel from benzaldehyde compounds and phenolic compounds according to claim 1, characterized in that, The first step involves setting the molar ratio between phenolic compounds and benzaldehyde compounds to be 2:1 to 6:

1.

3. A method for preparing high-energy-density fuel from benzaldehyde compounds and phenolic compounds according to claim 1, characterized in that, The first step involves selecting one of the following catalysts: phosphotungstic acid, phosphomolybdic acid, acidic resin, molecular sieve, metal oxide, sulfate-modified, acidic resin, or molecular sieve. The metal oxide is Cs-HPW / SiO2, and the sulfate-modified catalyst is SO4. 2- / ZrO2-TiO2, the acidic resin is one of Amberlyst-15, Nafion, T-62MP, D600, CD750, the molecular sieve is one of H-β, HY, H-ZSM5, Al-MCM-41; the mass of the acidic catalyst is 5-25 wt% of the mass of benzaldehyde.

4. A method for preparing high-energy-density fuel from benzaldehyde compounds and phenolic compounds according to claim 1, characterized in that, The first step involves a reaction temperature between 60-140℃ and a reaction time between 2-10 hours.

5. A method for preparing high-energy-density fuel from benzaldehyde compounds and phenolic compounds according to claim 1, characterized in that, In the second step, Metal / C is one or more of Ni / C, Pd / C, Pt / C, Ru / C, and Rh / C, and the solid acid catalyst is one or more of USY, MCM-41, HY, H-ZSM-5, H-Beta, and H-MOR; wherein the mass of Metal / C and the solid acid catalyst are 5% and 10% of the mass of the bisphenol product, respectively.

6. A method for preparing high-energy-density fuel from benzaldehyde compounds and phenolic compounds according to claim 1, characterized in that, The second step involves a hydrogenation deoxygenation reaction carried out in a batch reactor; the reaction temperature is between 140-200℃, the reaction time is between 6-14h, and the hydrogen pressure is 1-4MPa.

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