99-57-0Relevant academic research and scientific papers
Preparation method of 2-amino-4-nitrophenol
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Paragraph 0037-0079, (2021/05/29)
The invention provides a preparation method of 2-amino-4-nitrophenol, which comprises the steps of (1) dissolving 2-aminophenol in a solvent to react with concentrated sulfuric acid to generate 2-aminophenol sulfate, and passivating an amino group; (2) carrying out nitration reaction on the generated 2-aminophenol hydrogen sulfate and a mixed acid of concentrated sulfuric acid and concentrated nitric acid, and selectively nitrating at the 4 position to obtain 2-amino-4-nitrophenol; and (3) finally, processing the 2-amino-4-nitrophenol crude product into a 2-amino-4-nitrophenol refined product. According to the method provided by the invention, the defects of poor selectivity of sulfide, hydrazine hydrate or palladium carbon and the like can be avoided; and the preparation method provided by the invention is simple to operate, and the prepared product is good in appearance, good in quality and high in yield and has a good industrial prospect.
A Common, Facile and Eco-Friendly Method for the Reduction of Nitroarenes, Selective Reduction of Poly-Nitroarenes and Deoxygenation of N-Oxide Containing Heteroarenes Using Elemental Sulfur
Cerecetto, Hugo,Romero, Angel H.
supporting information, (2020/03/23)
A transition metal-free, environment-friendly and practical protocol was developed either for the reduction of nitroarenes or for the deoxygenation of N-oxide containing heteroarenes. The reaction proceeded with the use of a non-toxic and cheap feedstock as elemental sulfur in aqueous methanol under relatively mild conditions. Green chemistry credentials were widely favorable compared to traditional and industrial protocols with good E-factors and a low production of waste. The strategy allowed the efficient reduction of a large variety of substituted-nitroarenes including various o-nitroanilines as well as selective reduction of various poly-nitroarenes in excellent yields with a broad substrate scope. The protocol was successfully extended to the deoxygenation of some N-oxide containing heteroarenes, like benzofuroxans, phenazine N,N'-dioxides, pyridine N-oxides, 2H-indazole N1-oxides, quinoxaline N1,N4-dioxides and benzo[d]imidazole N1,N3-dioxides. A gram-scale example for the synthesis of luminol, in green conditions, was reported. A solid mechanism of reaction was proposed from experimental evidences.
Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes
Hu, Zenan,Ai, Yongjian,Liu, Lei,Zhou, Junjie,Zhang, Gang,Liu, Hongqi,Liu, Xiangyu,Liu, Zhibo,Hu, Jianshe,Sun, Hong-bin,Liang, Qionglin
supporting information, p. 3146 - 3154 (2019/05/10)
Control of chemoselectivity is a special challenge for the reduction of nitroarenes bearing one or more unsaturated groups. Here, we report a flower-like Rh/α-FeOOH catalyst for the chemoselective hydrogenation of nitrostyrene to vinylaniline over full conversion, which benefits the new functionalized aminostyrene because the multisubstituted aminostyrenes are usually commercially unavailable. This catalyst does not only show desirable selectivity for the vinylanilines, but also exhibits the inertness to various other reducible groups over wide reaction duration. The catalytic selectivity for the reduction of the nitro group towards vinyl group was investigated by the control experiments and FT-IR analysis. We have found that the abundant hydroxyl groups in the α-FeOOH may contribute to the improvement of catalytic activity and selectivity. Furthermore, the catalyst exhibits excellent stability and keeps its catalytic performance even after 6 cycles. (Figure presented.).
Method for synthesizing benzoxazole compound by using nitration by-products of aromatic hydrocarbon and application of benzoxazole compound
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, (2019/09/14)
The invention discloses a method for synthesizing a benzoxazole compound by using nitration by-products of aromatic hydrocarbon and application of the benzoxazole compound. The method comprises the main process: performing step-by-step crystallization on nitration products of a 2,4-dinitrochlorobenzene production enterprise so as to obtain 2,4-dinitrochlorobenzene, 2,6-dinitrochlorobenzene (I) anda small amount of residues, adopting the obtained 2,6-dinitrochlorobenzene (I) as the main starting material, and performing hydrolysis, selective catalytic hydrogenation reduction, cyclization, halogenation, carbon-carbon coupling and other processes so as to synthesize the benzoxazole compound, wherein the obtained compound can be used as a main raw material to synthesize a series of chemical intermediates with important application, and the chemical intermediates include o-aminophenol, 2-amino-4-nitrophenol, 2-amino-5-nitrophenol and hydrochloride of o-aminophenol, 2-amino-4-nitrophenol, 2-amino-5-nitrophenol. Through the method, the industrial by-products are converted into high value-added aromatic aminophenol products, industrial hazardous waste of the 2,4-dinitrochlorobenzene production enterprise is reduced, the scope of products of the enterprise is widened, and the economic benefits of enterprise are increased.
Ultrafine FeCu Alloy Nanoparticles Magnetically Immobilized in Amine-Rich Silica Spheres for Dehalogenation-Proof Hydrogenation of Nitroarenes
Bao, Hongjie,Li, Yunong,Liu, Lei,Ai, Yongjian,Zhou, Junjie,Qi, Li,Jiang, Ruihang,Hu, Zenan,Wang, Jingting,Sun, Hongbin,Liang, Qionglin
supporting information, p. 14418 - 14424 (2018/09/12)
A novel core–shell structured nanocatalyst (Fe3O4@SiO2-NH2-FeCu nanoparticles) with ultrafine FeCu alloy NPs magnetically immobilized in porous silica has been fabricated. The obtained catalyst revealed excellent activity and chemoselectivity for catalyzing the hydrogenation of nitroarenes to corresponding anilines using hydrazine hydrate as the hydrogen source, and the reaction could be carried out smoothly in water, which is an environmentally friendly solvent. The FeCu alloy effectively prevented the dehalogenation of halonitroarenes, and X-ray photoelectron spectroscopy (XPS) study showed that it resulted from the electron-enrichment of Fe from Cu. A kinetics study indicated that the reaction order was about 1.5 towards 4-CNB and the apparent active energy (Ea) was 48.1 kJ mol?1, which is a relatively low value. Furthermore, the FeCu NPs are magnetically immobilized in the silica spheres (Fe3O4@SiO2), therefore the catalyst can be easily recovered by use of an external magnet and also possesses a long life time.
Porous silica-encapsulated and magnetically recoverable Rh NPs: A highly efficient, stable and green catalyst for catalytic transfer hydrogenation with "slow-release" of stoichiometric hydrazine in water
Zhou, Junjie,Li, Yunong,Sun, Hong-Bin,Tang, Zhike,Qi, Li,Liu, Lei,Ai, Yongjian,Li, Shuang,Shao, Zixing,Liang, Qionglin
supporting information, p. 3400 - 3407 (2017/07/28)
A core-shell structured nanocatalyst (Fe3O4@SiO2-NH2-RhNPs@mSiO2) that is encapsulated with porous silica has been designed and prepared for catalyzing the transfer hydrogenation of nitro compounds into corresponding amines. Rh nanoparticles serve as the activity center, and the porous silica shell plays an important role in the "slow-release" of the hydrogen source hydrazine. This reaction can be carried out smoothly in the green solvent water, and the atom economy can be improved by decreasing the amount of hydrazine hydrate used to a stoichiometric 1.5 equivalent of the substrate. Significantly, high catalytic efficiency is obtained and the turnover frequency (TOF) can be up to 4373 h-1 in the reduction of p-nitrophenol (4-NP). A kinetics study shows that the order of reaction is ～0.5 towards 4-NP, and the apparent active energy Ea is 58.18 kJ mol-1, which also gives evidence of the high catalytic efficiency. Additionally, the excellent stability of the catalyst has been verified after 15 cycles without any loss of catalytic activity, and it is easily recovered by a magnet after reaction due to the Fe3O4 nucleus.
Method for recovering 2,4-dinitrophenol hydrogenation reduction byproduct to prepare 2-amino-4-acetamidoanisole
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Paragraph 0019-0022, (2017/07/22)
The invention discloses a method for recovering 2,4-dinitrophenol hydrogenation reduction byproduct to prepare 2-amino-4-acetamidoanisole. The method comprises the following steps: separating a 2-amino-4-nitrophenol and 2-nitro-4-aminophenol mixture to obtain a 2-nitro-4-aminophenol single component; mixing the 2-nitro-4-aminophenol with an alkylation reagent, and carrying out a phenolic hydroxyl group alkylation reaction and an amino group acylation reaction to obtain 2-nitro-4-acetamidoanisole; and carrying out nitro group reduction on the 2-nitro-4-acetamidoanisole to obtain the 2-amino-4-acetamidoanisole. The method provides a brand new method for the synthesis of the fine chemical engineering intermediate 2-amino-4-acetamidoanisole with important uses, reduces the content of organic matters in 2-amino-4-nitrophenol production wastewater, reduces the treatment difficulty of enterprises' industrial wastewater, converts wastewater components into the fine chemical engineering intermediate with important production uses, and increases the enterprises' economy income.
Method for preparing 2-amino-4-nitrophenol through selective catalytic hydrogenation reduction
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Paragraph 0008; 0018-0020, (2017/08/31)
The invention discloses a method for preparing 2-amino-4-nitrophenol through selective catalytic hydrogenation reduction. The method roughly comprises the processes of obtaining a 2,4-sodium dinitrobenzene water solution through reaction of 2,4-dinitrochlorobenzene and a 10%-30% sodium hydroxide solution, mixing the 2,4-sodium dinitrobenzene water solution with an acid and an organic solvent to obtain a mixed solution of 2,4-dinitrophenol and an organic solvent; and mixing the mixed solution of 2,4-dinitrophenol and an organic solvent with hydrogen in the presence of a noble metal catalyst, and producing 2-amino-4-nitrophenol through selective catalytic hydrogenation reduction. According to the method, the problems that 2-amino-4-nitrophenol is high in salinity, much in wastewater and high in production cost in an existing production method of 2-amino-4-nitrophenol are solved, and an environment-friendly method which is low in production cost is provided for production of high-quality 2-amino-4-nitrophenol.
Visible Light as a Sole Requirement for Intramolecular C(sp3)-H Imination
Li, Jingjing,Zhang, Pengxiang,Jiang, Min,Yang, Haijun,Zhao, Yufen,Fu, Hua
, p. 1994 - 1997 (2017/04/28)
A novel, simple, and practical visible-light-mediated intramolecular α-C(sp3)-H imination of tertiary aliphatic amines containing β-O-aryl oximes leading to N-heterocycles has been developed. The reaction was performed well at rt with tolerance of some functional groups. Importantly, the selective C-H functionalization did not require added catalyst, oxidant, additive, acid, and base; visible light was the sole requirement.
2-amino-4-nitrophenol synthesis method
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Paragraph 0026; 0027; 0028; 0029; 0030; 0031; 0032-0056, (2017/08/31)
The invention discloses a 2-amino-4-nitrophenol synthesis method, comprising the following specific steps: 1, in an organic solvent, enabling 2-aminophenol (I) to react with hydrochloric acid or sulfuric acid to synthesize a compound (II), and directly performing the next step without recycling the organic solvent; 2, in the organic solvent, performing nitration on the compound (II) by using nitric acid at low temperature to obtain a compound (III), and finishing the reaction; 3, adding liquid caustic soda into a system, recovering the organic solvent by distillation, mixing distillation residues with inorganic acid, and performing solid and liquid separation to obtain a compound (IV), performing distillation and concentration on mother liquor to obtain a commercialized by-product, sodium chloride or sodium sulfate, and recycling and reusing distillation cooling water for reaction. The process is basically shown as a chemical equation shown in the description, wherein R is chloridion and hydrogen sulfate radical ions. The method provided by the invention has the advantages that the technological continuous operability is high, the safety is high, waste is avoided, the required production equipment is common reaction equipment, and the industrialization is easier to realize.
