Method and catalyst for preparing amino aromatic hydrocarbon by hydrogenation of nitro aromatic hydrocarbon

Abstract

The invention relates to a method and a catalyst for preparing amino aromatic hydrocarbon through hydrogenation of nitroaromatic hydrocarbon containing easily reduced groups such as nitrophenylacetylene. According to the method, Fe-N / C prepared by an impregnation-pyrolysis method is used as a catalyst, absolute ethyl alcohol is used as a solvent, hydrazine hydrate is used as a hydrogen source, and nitro-aromatic hydrocarbon is catalyzed to be hydrogenated at 30-100 DEG C to prepare amino-aromatic hydrocarbon. The catalyst has high activity and high selectivity on nitro hydrogenation in nitro aromatic hydrocarbon, and when the conversion rate of nitrophenylacetylene is 100%, the selectivity of aminophenylacetylene is gt; the reaction time is continuously prolonged, and the selectivity of the aminophenylacetylene is basically unchanged. For hydrogenation of other nitro aromatic hydrocarbons, the selectivity gt of amino aromatic hydrocarbons can be realized under the conversion rate of 100%; 96%.

Description

Technical Field

[0001] This invention relates to a method and catalyst for the selective hydrogenation of nitroaromatics to prepare aminoaromatics. Specifically, it relates to a method for the selective hydrogenation of nitroaromatics to prepare aminoaromatics using Fe-N / C prepared by impregnation-pyrolysis as a catalyst, in ethanol (a green solvent), and hydrazine hydrate as a hydrogen source. Background Technology

[0002] Amino aromatics are crucial chemical raw materials and intermediates in agriculture, fine chemicals, and pharmaceuticals. Currently, the most suitable method for preparing amino aromatics from nitro aromatics is catalytic hydrogenation reduction. Since many nitro aromatics contain one or more easily reducible groups, it is important to find a method that preferentially catalyzes the hydrogenation of nitro groups without hydrogenating other easily reducible groups such as alkynyl, alkenyl, and halogen groups.

[0003] The research progress on the application of noble metal catalysts is as follows. Using toluene as solvent and 0.2 wt% Pt / TiO2 as catalyst, the hydrogenation of 4-nitrobenzylene was catalyzed under conditions of 6 bar H2 and 313 K for 5.6 h, achieving a conversion rate of 98.9% and a selectivity of 90.1% for 4-aminophenylacetylene. Corma, et al., J. Am. Chem. Soc., 2008 Using Pt-Zn / SnO2-Sb2O3 as a catalyst, in ethanol, under conditions of 50 °C and 4 MPa H2 for 20 min, the hydrogenation conversion of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 87.9%. CN 107216255 B Using ammonia borane as the hydrogen source, PtZn / HNCNT catalyzed the hydrogenation of 4-nitrophenylacetylene in a mixed solvent of ethanol and water at 40 °C for 4 h, achieving a conversion rate >99% and a selectivity of 99% for 4-aminophenylacetylene. Aijuan Han, et al., Nat. Commun., 2019 In the presence of CO and H2, using toluene-water as the reaction medium, 4-nitrobenzylene hydrogenation was catalyzed by 0.25% Pt / α-MoC for 4 h, achieving a conversion rate of 100% and a selectivity of 99.9% for 4-aminophenylacetylene. Lili Lin, et al., Nat. Nanotech., 2019 Using PdCd 1.13 Catalytic hydrogenation of 4-nitrophenylacetylene was carried out in DMF at 60 °C for 3 h using HCOONH4 as the hydrogen source. The reactants were completely converted, and the selectivity for 4-aminophenylacetylene was 92%. Yonggang Feng, et al., J. Am. Chem. Soc., 2020 Using Pt / TAPT-COF as a catalyst and ethanol as a solvent, the hydrogenation reaction of halonitrobenzene in H2 at 30 °C for 3 h achieved a conversion rate of 100%, and the selectivity for haloaniline was 100%. Mengmeng Gao, et al., Green. Chem., 2024 ).

[0004] Using non-precious metal catalysts can reduce costs, and research progress is as follows. Using CoS… xUsing a catalyst, at 108 °C and 1000 psig H2 pressure, the reaction of 3-nitrophenylacetylene for 0.75 h yielded 86% of 3-aminophenylacetylene. Anatoly Onopchenko, et al., J. Org. Chem., 1979 A nitrogen-doped Fe-phenanthroline / C catalyst, prepared by high-temperature pyrolysis at 800 °C using Fe(OAc)₂ as a metal precursor, 1,10-phenanthroline as a nitrogen source, and carbon powder as a support, was used to catalyze the reaction of 4-nitrophenylacetylene at 100 °C for 10 h with hydrazine hydrate as a hydrogen source and tetrahydrofuran as a solvent. The reactant conversion was 100%, the selectivity for 4-aminophenylacetylene was 96%, and the TOF value calculated based on Fe atoms was 10 h⁻¹. -1 ( Rajenahally V . Jagadeesh,et al., Chem. Commun., 2011 Based on this, at 105 °C and 50 bar H2 pressure, 60 mg of Fe-phenanthroline / C was used in a 1:1 water-tetrahydrofuran solvent to catalyze the reaction of 4-nitrophenylacetylene for 26 h, with a yield of 75% for 4-aminophenylacetylene. Rajenahally V. Jagadeesh, et al., Science, 2013 A 3 wt% Co-phenanthroline / C catalyst prepared by high-temperature pyrolysis catalyzed the hydrogenation of 4-nitrophenylacetylene in tetrahydrofuran solvent. The reaction was carried out at 110 °C and 50 bar H₂ pressure for 4 h, yielding 88% 4-aminophenylacetylene. Felix A. Westerhaus, et al., Nat. Chem., 2013 Using α-Fe₂O₃ as a catalyst, the hydrogenation of 4-nitrophenylacetylene was catalyzed in ethanol with hydrazine hydrate as the hydrogen source at 120 °C for 10 min, achieving a 100% conversion rate and a 96.1% selectivity for 4-aminophenylacetylene. Using Fe₂O₃ / Al₂O₃ prepared by co-precipitation as a catalyst, the selective hydrogenation of nitrobenzeneacetylene was catalyzed in ethanol with hydrazine hydrate as the hydrogen source at 80 °C for 15 min, achieving a 100% conversion rate and a 96.2% selectivity for 4-aminophenylacetylene. Using Fe₂O₃-CeO₂ / TiO₂ as a catalyst, the selective hydrogenation of nitrobenzeneacetylene was catalyzed in ethanol with hydrazine hydrate as the hydrogen source at 120 °C for 10 min, achieving a 100% conversion rate and a 94.5% selectivity for 4-aminophenylacetylene. CN 117800846 A、CN 117820126 A、CN 115445626 A Using a MoO3 / TiO2 catalyst, anhydrous ethanol as solvent, and hydrazine hydrate as hydrogen source, the reaction was carried out at 80 °C for 10 min. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 99.1%. CN 118084675 A ).

[0005] Using non-precious metal catalysts can significantly reduce costs, but the following main problems still exist: (1) The reaction is mostly carried out in harmful and volatile organic solvents such as tetrahydrofuran and toluene, which can easily pollute the environment; (2) The above Fe-phenanthroline / C catalysts have low activity and require high reaction temperatures. Summary of the Invention

[0006] This invention relates to a method for selectively hydrogenating nitroaromatics to aminoaromatics using Fe-N / C prepared by impregnation-pyrolysis as a catalyst in ethanol, a green solvent, and hydrazine hydrate as a hydrogen source.

[0007] The technical solution adopted in this invention is as follows: anhydrous ethanol, nitroaromatic hydrocarbons, catalyst Fe-N / C and 80% N2H4·H2O solution are added to the reactor. The mass ratio of catalyst to nitrophenylacetylene is (0.1~0.6):1, and the molar ratio of hydrazine hydrate to nitroaromatic hydrocarbons is (1.8~6.6):1. The air is purged with high-purity nitrogen at room temperature. The reactor is heated to 30~100 ℃ and stirred after preheating for 20 min. The reaction continues until the conversion rate is close to or reaches 100%.

[0008] The nitroaromatic hydrocarbons mentioned are 2-chloronitrobenzene, 3-chloronitrobenzene, 4-chloronitrobenzene, 2-bromonitrobenzene, 3-bromonitrobenzene, 4-bromonitrobenzene, 3-iodonitrobenzene, 4-nitrobenzoic acid, 3-nitrobenzonitrile, 2-chloro-5-nitrobenzonitrile, 3-nitrostyrene, 4-nitrostyrene, 3-nitrophenylacetylene, and 4-nitrophenylacetylene.

[0009] The catalyst was prepared using the following impregnation-pyrolysis method: Fe(OAc)₂ was dissolved in ethanol, and 1,10-phenanthroline was added. The mixture was stirred at 60 °C for 2 h, and carbon powder was added. The stirring continued for 3 h, and the mixture was cooled to room temperature and stirred for 15 h. The mixture was then sonicated, evaporated to dryness, dried, and ground. The sample was calcined in a tube furnace at 750-850 °C under a nitrogen atmosphere for 2 h, with a nitrogen flow rate ranging from 50 to 3000 mL / min, to obtain the Fe-N / C catalyst. The mass percentage of Fe was 0.5% to 3%, and the molar ratio of Fe to 1,10-phenanthroline was 1:(2-5).

[0010] The present invention has the following advantages: (1) The process uses anhydrous ethanol as a green solvent, which avoids the reaction being carried out in harmful solvents such as toluene and tetrahydrofuran, thus reducing environmental pollution.

[0011] (2) The catalyst exhibits high selectivity for the hydrogenation of nitro groups in nitroaromatics. When the hydrogenation conversion of 4-nitrophenylacetylene at 60 °C is 100%, the selectivity for aminophenylacetylene is >95%. The catalyst shows almost no catalytic activity for the hydrogenation of acetylene groups. Therefore, after the reactants are completely converted, the selectivity for aminophenylacetylene does not decrease significantly even after extending the reaction time. Using the catalyst to catalyze the hydrogenation of other nitroaromatics, the yield of aminoaromatics is >96%, and the dehalogenation side reaction can be suppressed.

[0012] (3) The catalyst is prepared using non-precious metals, with low metal loading and high activity. The TOF value calculated based on Fe atoms in the reaction can reach 602 h. -1 .

[0013] In summary, using Fe-N / C as a catalyst and 80% hydrazine hydrate solution as a hydrogen source in anhydrous ethanol to catalyze the hydrogenation of nitroaromatics to aminoaromatics is a green, environmentally friendly, economical, and efficient process. Detailed Implementation

[0014] Example 1: Catalyst preparation and hydrogenation of 4-nitrophenylacetylene Carbon powder was added to a complex solution of Fe and 1,10-phenanthroline in a molar ratio of 1:2 and stirred. The mixture was then subjected to ultrasonication, rotary evaporation, drying, and grinding. The sample was pyrolyzed in a tube furnace at 800 °C under a nitrogen atmosphere for 2 h with a nitrogen flow rate of 3000 mL / min to obtain a Fe-N / C catalyst with a Fe mass percentage of 1.24 wt%.

[0015] In a reactor lined with 30 mL of polytetrafluoroethylene, 5 mL of ethanol, 0.5 mmol of 4-nitrophenylacetylene, a hydrazine hydrate solution with an 80% N2H4·H2O content (2 mmol of hydrazine hydrate), and 0.0225 g of the catalyst were added. The reactor was tightened, and high-purity nitrogen was purged for 5 min to remove air. The reactor was preheated in an oil bath at 100 °C for 20 min, and the stirring was turned on. The reaction times were 10 min and 30 min, respectively. The reaction products were analyzed by gas chromatography. After 10 min of reaction, the conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 97.6%. After 30 min of reaction, the conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 97%.

[0016] Example 2 Hydrogenation of 4-Nitrophenylacetylene The reaction temperature was 60 °C, the reaction time was 40 min, and the catalyst preparation process and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 96.1%.

[0017] Example 3 Hydrogenation of 4-Nitrophenylacetylene The reaction temperature was 30 °C, the reaction time was 8 h, and the catalyst preparation process and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 95.2%.

[0018] Example 4 Hydrogenation of 4-Nitrophenylacetylene A hydrazine hydrate solution with a N2H4·H2O content of 80% (0.9 mmol of hydrazine hydrate) was added, and the reaction time was 2 h. The catalyst preparation process and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 99.7%, and the selectivity of 4-aminophenylacetylene was 95.8%.

[0019] Example 5 Hydrogenation of 4-Nitrophenylacetylene A hydrazine hydrate solution with a N2H4·H2O content of 80% (3.3 mmol of hydrazine hydrate) was added, and the reaction time was 10 min. The catalyst preparation process and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 96.1%.

[0020] Example 6 Hydrogenation of 4-Nitrophenylacetylene 0.045 g of the catalyst was added, the reaction temperature was 60 °C, and the reaction time was 25 min. The catalyst preparation process and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 97%.

[0021] Comparative Example 1: Hydrogenation of 4-nitrophenylacetylene 5 mL of tetrahydrofuran was added as a solvent, and the reaction time was 30 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 90.1%.

[0022] Example 7 Catalyst preparation and hydrogenation of 4-nitrophenylacetylene The catalyst was prepared with Fe added at a molar ratio of 1:3 to 1,10-phenanthroline, for a reaction time of 10 min, and other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 98%.

[0023] Example 8 Catalyst preparation and hydrogenation of 4-nitrophenylacetylene A Fe-N / C catalyst with a Fe mass percentage of 3 wt% was prepared. During sample pyrolysis, the nitrogen flow rate was 50 mL / min, the reaction temperature was 60 ℃, and the reaction time was 90 min. Other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 97.3%, and the selectivity of 4-aminophenylacetylene was 96.8%.

[0024] Example 9 Catalyst preparation and hydrogenation of 4-nitrophenylacetylene A Fe-N / C catalyst with a Fe content of 3 wt% was prepared, following the same preparation process as in Example 1, with a reaction temperature of 60 ℃ and a reaction time of 20 min, and other conditions as in Example 1. The conversion rate of 4-nitrophenylacetylene was 100%, and the selectivity of 4-aminophenylacetylene was 97.1%.

[0025] Comparative Example 2: Catalyst Preparation and Hydrogenation of 4-Nitrophenylacetylene During sample pyrolysis, the nitrogen flow rate was 10 mL / min, the reaction temperature was 100 ℃, and the reaction time was 30 min. Other conditions were the same as in Example 1. The conversion rate of 4-nitrophenylacetylene was 29.5%, and the selectivity of 4-aminophenylacetylene was 35.4%.

[0026] Example 10 Hydrogenation of 3-Nitrophenylacetylene The catalyst and preparation method were the same as in Example 1. The reactant was 3-nitrophenylacetylene, the reaction time was 30 min, and other conditions were the same as in Example 1. The conversion rate of 3-nitrophenylacetylene was 100%, and the selectivity of 3-aminophenylacetylene was 97.7%.

[0027] Example 11 Hydrogenation of 2-chloronitrobenzene 0.5 mmol of 2-chloronitrobenzene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 2-chloronitrobenzene was 100%, and the selectivity of 2-chloroaniline was 100%.

[0028] Example 12 Hydrogenation of 4-chloronitrobenzene 0.5 mmol of 4-chloronitrobenzene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 4-chloronitrobenzene was 100%, and the selectivity of 4-chloroaniline was 100%.

[0029] Example 13 Hydrogenation of 3-bromonitrobenzene 0.5 mmol of 3-bromonitrobenzene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 3-bromonitrobenzene was 100%, and the selectivity of 3-bromoaniline was 100%.

[0030] Example 14 Hydrogenation of 3-iodonitrobenzene 0.5 mmol of 3-iodonitrobenzene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 3-iodonitrobenzene was 100%, and the selectivity of 3-iodoaniline was 100%.

[0031] Example 15 Hydrogenation of 3-Nitrobenzonitrile 0.5 mmol of 3-nitrobenzene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 3-nitrobenzene was 100%, and the selectivity of 3-aminobenzonitrile was 98.8%.

[0032] Example 16 Hydrogenation of 4-Nitrobenzoic Acid 0.5 mmol of 4-nitrobenzoic acid was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 4-nitrobenzoic acid was 100%, and the selectivity of 4-aminobenzoic acid was 100%.

[0033] Example 17 Hydrogenation of 2-chloro-5-nitrobenzene 0.5 mmol of 2-chloro-5-nitrobenzene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 20 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 2-chloro-5-nitrobenzene was 100%, and the selectivity of 2-chloro-5-aminobenzonitrile was 97%.

[0034] Example 18 Hydrogenation of 3-Nitrostyrene 0.5 mmol of 3-nitrostyrene was added as a reactant, the reaction temperature was 60 °C, and the reaction time was 40 min. The catalyst and other conditions were the same as in Example 1. The conversion rate of 3-nitrostyrene was 100%, and the selectivity of 3-aminostyrene was 96.2%.

Claims

1. A method and catalyst for the hydrogenation of nitroaromatics to prepare aminoaromatics, characterized in that... Anhydrous ethanol, nitroaromatic reactants, Fe-N / C catalyst calcined at 750-850 °C, and 80% hydrazine hydrate solution were added to the reactor. The mass ratio of catalyst to nitrobenzeneacetylene was (0.1~0.6):1, and the molar ratio of hydrazine hydrate to nitroaromatics was (1.8~6.6):

1. The reactor was purged with high-purity nitrogen at room temperature to remove air, and then heated to 30~100 °C. After preheating for 20 min, stirring was started, and the reaction was continued until the conversion rate approached or reached 100%. The Fe-N / C catalyst has an Fe mass percentage of 0.5% to 3%. The Fe-N / C catalyst was calcined for 2 h in a tube furnace at 750-850 ℃ in an atmosphere of nitrogen flow rate of 50~3000 mL / min; The nitroaromatic hydrocarbons mentioned are 2-chloronitrobenzene, 3-chloronitrobenzene, 4-chloronitrobenzene, 2-bromonitrobenzene, 3-bromonitrobenzene, 4-bromonitrobenzene, 3-iodonitrobenzene, 4-nitrobenzoic acid, 3-nitrobenzonitrile, 2-chloro-5-nitrobenzonitrile, 3-nitrostyrene, 4-nitrostyrene, 3-nitrophenylacetylene, and 4-nitrophenylacetylene.

2. The method and catalyst for the hydrogenation of nitroaromatics to aminoaromatics according to claim 1, characterized in that, The Fe-N / C catalyst is prepared by impregnation-pyrolysis method. Fe(OAc)2 is dissolved in ethanol, and a certain proportion of 1,10-phenanthroline is added to it. The molar ratio of Fe to 1,10-phenanthroline is 1:(2~5). After forming a complex solution, carbon powder is added for impregnation and drying. Then, it is calcined at 750-850 ℃ for 2 h in a nitrogen atmosphere.