95-82-9Relevant articles and documents
Method for synthesizing 2, 5-dichloroaniline by kettle-type continuous hydrogenation
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Paragraph 0024-0033, (2021/03/13)
The invention provides a method for synthesizing 2, 5-dichloroaniline by kettle-type continuous hydrogenation. The method involves a feeding pump, a preheater, a reactor, a gas-liquid separator and anextraction pump, the feeding pump, the preheater, the reactor, the gas-liquid separator and the extraction pump are sequentially connected in series, and a plurality of hydrogen distribution pipes are arranged in the reactor, a plurality of through holes are formed in the side surface of the hydrogen distribution pipes, and a catalyst is arranged in the hydrogen distribution pipes; the method forsynthesizing 2, 5-dichloroaniline through kettle-type continuous hydrogenation comprises the following steps of: inputting a 2, 5-dichloronitrobenzene solution into the reactor through the feeding pump, inputting hydrogen into the reactor, adsorbing the hydrogen through the catalyst, and then reacting the hydrogen with the 2, 5-dichloronitrobenzene solution to generate 2, 5-dichloroaniline; by adopting the catalyst with high nitro-reduction activity, byproducts are few, and efficient conversion of the raw materials can be realized only at a reaction temperature of 50-80DEG C. By adopting themethod to continuously react for 720 hours, the raw material conversion rate is greater than 95%, and the product selectivity is greater than 95%.
Fabrication of magnetically separable ruthenium nanoparticles decorated on channelled silica microspheres: Efficient catalysts for chemoselective hydrogenation of nitroarenes
Das, Manash R.,Das, Pankaj,Kalita, Gauravjyoti D.
, p. 13483 - 13496 (2021/10/12)
Fe3O4-SiO2microspheres were synthesized by a three-step synthetic procedure involving silica coating, surface capping, and surface modification. These magnetic mesoporous microspheres were employed as sorbents for the incorporation of ultrasmall Ru nanoparticles (2-5 nm) followed by thermal aggregation of the microspheres for achieving better heterogeneity and low leaching. The Ru decorated Fe3O4-SiO2microspheres (Ru@Fe3O4-CSM) were applied as chemoselective catalysts to convert more than 20 substituted nitroarenes to corresponding amines with good-to-excellent conversion (77-99%) and selectivity (70-100%) under mild conditions; the catalyst can be magnetically recovered within a frame of 90s (recovery time-lapse) and reused up to 5 times without significant decrease in activity or selectivity. Magnetic hysteresis studies were performed to elucidate the magnetic behavior of the ruthenium decorated materials.
A mild and selective Cu(II) salts-catalyzed reduction of nitro, azo, azoxy, N-aryl hydroxylamine, nitroso, acid halide, ester, and azide compounds using hydrogen surrogacy of sodium borohydride
Kalola, Anirudhdha G.,Prasad, Pratibha,Mokariya, Jaydeep A.,Patel, Manish P.
supporting information, p. 3565 - 3589 (2021/10/12)
The first mild, in situ, single-pot, high-yielding well-screened copper (II) salt-based catalyst system utilizing the hydrogen surrogacy of sodium borohydride for selective hydrogenation of a broad range of nitro substrates into the corresponding amine under habitancy of water or methanol like green solvents have been described. Moreover, this catalytic system can also activate various functional groups for hydride reduction within prompted time, with low catalyst-loading, without any requirement of high pressure or molecular hydrogen supply. Notably, this system explores a great potential to substitute expensive traditional hydrogenation methodologies and thus offers a greener and simple hydrogenative strategy in the field of organic synthesis.
Commercially Available CuO Catalyzed Hydrogenation of Nitroarenes Using Ammonia Borane as a Hydrogen Source
Du, Jialei,Chen, Jie,Xia, Hehuan,Zhao, Yiwei,Wang, Fang,Liu, Hong,Zhou, Weijia,Wang, Bin
, p. 2426 - 2430 (2020/03/30)
Tandem ammonia borane dehydrogenation and nitroarenes hydrogenation has been reported as a novel strategy for the preparation of aromatic amines. However, the practical application of this strategy is subjected to the high-cost and tedious preparation of supported noble metal nanocatalysts. The commercially available CuO powder is herein demonstrated to be a robust catalyst for hydrogenation of nitroarenes using ammonia borane as a hydrogen source under mild conditions. Numerous amines (even sterically hindered, halogenated, and diamines) could be obtained through this method. This monometallic catalyst is characteristic of support-free, excellent chemoselectivity, low-cost, and high recyclability, which will favor its future utilization in preparative reduction chemistry. Mechanistic studies are also carried out to clarify that diazene and azoxybenzene are key intermediates of this heterogeneous reduction.
A new process to prepare 3,6-dichloro-2-hydroxybenzoic acid, the penultimate intermediate in the synthesis of herbicide dicamba
Walker, Daniel P.,Harris, G. Davis,Carroll, Jeffery N.,Boehm, Terri L.,McReynolds, Matthew D.,Struble, Justin R.,van Herpt, Jochem,van Zwieten, Don,Koeller, Kevin J.,Bore, Mangesh
, p. 1032 - 1036 (2019/03/17)
Glyphosate [N-(phosphonomethyl)glycine] is a broad spectrum, post-emergent herbicide that is among the most widely used agrochemicals globally. Over the past 30 years, there has been a development of glyphosate-resistant weeds, which pose a significant challenge to growers and crop scientists, resulting in lower crop yields and increased costs. 3,6-Dichloro-2-methoxybenzoic acid (dicamba) is the active ingredient in XtendiMax a standalone herbicide developed by Bayer Crop Science to control broadleaf weeds, including glyphosate-resistant species. 3,6-Dichloro-2-hydroxybenzoic acid (3,6-DCSA) is the penultimate intermediate in the synthesis of dicamba. Existing dicamba manufacturing routes utilize a high temperature, high pressure Kolbe-Schmitt carboxylation to prepare 3,6-DCSA. Described in this Letter is a new, non-Kolbe-Schmitt process to prepare 3,6-DCSA from salicylic acid in four chemical steps.
Catalytic hydrogenation process of chlorine-containing nitro aromatic compound
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Paragraph 0024; 0025; 0026; 0027, (2018/11/27)
The invention discloses a catalytic hydrogenation process of a chlorine-containing nitro aromatic compound. The specific process comprises the following steps: adding a chlorine-containing nitrobenzene, water and an anti-dechlorination agent into a reactor, carrying out mixing by stirring, then adding a catalyst and a self-prepared cocatalyst, introducing nitrogen into the reactor for 5-10 min toreplace air in the reactor, then introducing hydrogen until the pressure is 18-26 kg, carrying out a reaction at 55-75 DEG C for 1-3 hours, carrying out cooling to room temperature after the reactionis finished, and detecting the content of the target product in the obtained product. The process conditions are mild, the effect of the reaction substrate on the catalyst is small, the catalytic activity is high, and the yield of the product is high.
Preparation method of 2,5-dichloroaniline
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Paragraph 0022; 0024-0076, (2017/08/29)
The invention provides a preparation method of 2,5-dichloroaniline, and belongs to the field of compound preparation. Under the effects of oxidizing agents, aminating agents, metal complex catalysts and cocatalysts, 1,4-dichlorobenzene is used as raw materials; one from water, methanol, acetonitrile, acetic acid and ethyl alcohol or a composition of more than one in water, methanol, acetonitrile, acetic acid and ethyl alcohol is used as a solvent; reaction is carried out at the reaction temperature being 15 to 95 DEG C for 1 to 96h to obtain 2,5-dichloroaniline. The method provided by the invention has the advantages that the catalyst system has high oxidative amination reaction efficiency and high yield; the reaction conditions are relatively mild; the side reaction is little; products can be conveniently separated; the reaction time is greatly shortened; the preparation method can be popularized to large-scale industrial production.
Method for synthesizing 2,5-dichloroaniline by micro-channel reactor
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Paragraph 0044; 0049; 0055; 0056; 0057; 0063; 0064, (2017/08/28)
The invention provides a method for synthesizing 2,5-dichloroaniline by a micro-channel reactor. A nitratlon reaction and a catalytic hydrogenation reaction are performed by using the micro-channel reactor. The method comprises the following steps of nitratlon reaction: raw materials of nitro-p-dichlorobenzene are dissolved into an organic solvent, and are preheated; concentrated nitric acid and concentrated sulfuric acid are mixed and are preheated; the materials enter a reaction module group to take a reaction after the preheating; and an intermediate product of 2,5-Dichloronitrobenzene is obtained after the refining; and catalytic hydrogenation reaction: the 2,5-Dichloronitrobenzene is dissolved into a solvent; Pd-loaded active carbon catalysts are added; dechlorination inhibitors are added, and then, preheating is performed; after the materials are preheated, hydrogen gas enters the reaction module group to take a reaction; and post-treatment is performed to obtain the 2,5-dichloroaniline. The method provided by the invention has the advantages that the mixing effect is good; the temperature and material proportion control is precise; the reaction yield and the product purity are improved; the reaction is safe and stable; the time is short; no amplification effect exists; and wide application prospects are realized in industrial production.
Distinctive size effects of Pt nanoparticles immobilized on Fe3O4@PPy used as an efficient recyclable catalyst for benzylic alcohol aerobic oxidation and hydrogenation reduction of nitroaromatics
Long, Yu,Yuan, Bing,Niu, Jianrui,Tong, Xin,Ma, Jiantai
, p. 1179 - 1185 (2015/02/19)
Fe3O4@PPy composite microspheres have been synthesized using Fe3O4 microspheres as a chemical template in an ultrasonic treatment process. Pt nanoparticles (NPs) were immobilized on Fe3O4@PPy by using ethylene glycol (EG) and NaBH4 as reducing agents. The information on the morphologies, sizes, and dispersion of Pt NPs of the as-prepared catalysts was verified by TEM, XRD, FTIR and XPS. As expected, the chemical reduction methods remarkably affected the size of Pt NPs (～2.5 nm and ～5.5 nm) and the prepared catalysts exhibited high catalytic activities as well as awesome stabilities for aerobic oxidation of benzylic alcohols and hydrogenation reduction of nitroaromatics. It was highlighted that size effects for the catalytic properties of the two reactions were found to be quite different. Fe3O4@PPy-Pt (2.5 nm) afforded a higher conversion for benzylic alcohol aerobic oxidation, while the selectivities toward benzaldehyde over these two catalysts were similar. However, they showed almost the same catalytic performance for hydrogenation reduction of a majority of nitroaromatics. What is more, Fe3O4@PPy-Pt (5.5 nm) gave better activities than several nitroaromatics, which were relatively difficult to be hydrotreated under the same conditions. In addition, the EG reduced Fe3O4@PPy-Pt catalyst exhibited slightly poorer stability than the NaBH4 reduced Fe3O4@PPy-Pt catalyst in the recycle tests, which might be due to the agglomeration of small Pt NPs.
Facile protocol for reduction of nitroarenes using magnetically recoverable CoM0.2Fe1.8O4 (M = Co, Ni, Cu and Zn) ferrite nanocatalysts
Goyal, Ankita,Kapoor, Surbhi,Samuel, Pankaj,Kumar, Vinod,Singhal, Sonal
, p. 51347 - 51363 (2015/06/25)
Transition metal doped cobalt ferrite (CoM0.2Fe1.8O4 (M = Co, Ni, Cu, Zn)) nanoparticles were fabricated using the sol-gel methodology. The obtained ferrite nanoparticles were annealed at 400 °C and characterized using Fourier transform infra-red spectroscopy (FT-IR), X-ray diffraction (XRD), high resolution transmission electron microscopy (HR-TEM), vibrating sample magnetometry (VSM) and energy dispersive X-ray (EDX) and scanning transmission electron microscopy (STEM). In the FT-IR spectra two bands in the range 1000-400 cm-1 were observed corresponding to the M-O bond in the tetrahedral and octahedral sites. XRD patterns confirmed the formation of a cubic spinel structure with a Fd3m space-group. HR-TEM analysis revealed a quasi-spherical shape with particle sizes in the range 20-30 nm for all the synthesized ferrite nanoparticles. The lattice inter-planar distances of 0.29, 0.25, 0.21 and 0.16 nm obtained from HR-TEM corresponding to the (2 2 0), (3 1 1), (4 0 0) and (5 1 1) lattice planes respectively were in complete agreement with the XRD data. The EDX-STEM confirmed the elemental composition as per the desired stoichiometric ratio. The catalytic efficiency of the synthesized ferrite samples was explored for the reduction of nitrophenols. Cu substituted cobalt ferrite nanoparticles (CoCu0.2Fe1.8O4) possessed excellent catalytic activity while CoM0.2Fe1.8O4 (M = Co, Ni and Zn) were inactive for the same. The substrate scope of the developed protocol was also evaluated for the reduction of various CH3-, NH2-, Br-, Cl- etc. substituted nitroaromatic compounds.
