- Electrochemical synthesis of 2,5-dichloroaniline
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A procedure was proposed for electrochemical reduction of 2,5-dichloronitrobenzene to 2,5-dichloroaniline in aqueous-ethanolic solution of sulfuric acid. The procedure for preparing 2,5-dichloroanilinium sulfate was optimized. The influence exerted by the cathode material, nature and amount of the organic solvent, sulfuric acid concentration, and electrolysis temperature on the yield and quality of the target product was discussed.
- Islamgulova,Tomilov,Akhmerova,Gil'mkhanova,Sapozhnikov
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Read Online
- Self-powered continuous nitration method and device
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The invention belongs to the technical field of organic synthesis application, and particularly relates to a self-powered continuous nitration method and device. According to the method, a raw material (or a raw material solution) and mixed acid (or nitric acid) are added into a self-powered continuous reactor at the same time, reaction feed liquid continuously and circularly flows, is mixed and reacts in a tube pass through self-propelling force generated by stirring of an impeller, the mass and heat transfer process is completed, and the target requirement is met. According to the invention, the mass transfer and heat transfer efficiency can be improved, the heat exchange and heat transfer capabilities are improved, the reaction time is shortened, the risk degree of art is reduced, the thermal runaway risk is avoided, the reaction safety is improved, and the realization of chemical industry intrinsic safety large scale production is facilitated.
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Paragraph 0073-0081
(2021/07/17)
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- Nitration of aromatics with dinitrogen pentoxide in a liquefied 1,1,1,2-tetrafluoroethane medium
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Regardless of the sustainable development path, today, there are highly demanded chemical productions still operating that bear environmental and technological risks inherited from the previous century. The fabrication of nitro compounds, and nitroarenes in particular, is traditionally associated with acidic wastes formed in nitration reactions exploiting mixed acids. However, nitroarenes are indispensable for industrial and military applications. We faced the challenge and developed a greener, safer, and yet effective method for the production of nitroaromatics. The proposed approach comprises the application of an eco-friendly nitrating agent, namely dinitrogen pentoxide (DNP), in the medium of liquefied 1,1,1,2-tetrafluoroethane (TFE) - one of the most non-hazardous Freons. Importantly, the used TFE is not emitted into the atmosphere but is effortlessly recondensed and returned into the process. DNP is obtainedviathe oxidation of dinitrogen tetroxide with ozone. The elaborated method is characterized by high yields of the targeted nitro arenes, mild reaction conditions, and minimal amount of easy-to-utilize wastes.
- Fauziev, Ruslan V.,Kharchenko, Alexandr K.,Kuchurov, Ilya V.,Zharkov, Mikhail N.,Zlotin, Sergei G.
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p. 25841 - 25847
(2021/08/09)
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- Dehydroxyalkylative halogenation of C(aryl)-C bonds of aryl alcohols
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We herein report Cu mediated side-directed dehydroxyalkylative halogenation of aryl alcohols. C(aryl)-C bonds of aryl alcohols were effectively cleaved, affording the corresponding aryl chlorides, bromides and iodides in excellent yields. Aryl alcohols could serve as both aromatic electrophilic and radical synthetic equivalents during the reaction.
- Liu, Mingyang,Zhang, Zhanrong,Liu, Huizhen,Wu, Tianbin,Han, Buxing
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p. 7120 - 7123
(2020/07/14)
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- Preparation method of nitrification organic matter and prepared nitrification organic matter
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The invention discloses a preparation method of nitrification organic matter and the prepared nitrification organic matter, and relates to the technical field of organic synthesis. The preparation method of the nitrification organic substance comprises the following steps: introducing a nitrification acid liquid and molten-state organic matter to be nitrified into a microchannel reactor, and performing a reaction, wherein the organic matter to be nitrified is solid at normal temperature, and solidification and/or dissolution in the nitrification acid liquid does not occur in the organic matterto be nitrified after the organic matter to be nitrified is introduced into the microchannel reactor. According to the preparation method of the nitrification organic matter provided by the invention, the nitrification organic matter prepared by the method has a very good yield and purity without a solvent removal post-treatment process; in the whole process, no solvent participates in the reaction, so that the post-treatment process of solvent removal is avoided; and the method has high safety in the whole reaction process, adopts automation control, has high production efficiency and a greatly-improved production environment, and has larger industrial application value.
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Paragraph 0101-0104
(2019/07/29)
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- Inexpensive NaX (X = I, Br, Cl) as a halogen donor in the practical Ag/Cu-mediated decarboxylative halogenation of aryl carboxylic acids under aerobic conditions
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Versatile and practical Ag/Cu-mediated decarboxylative halogenation between readily available aryl carboxylic acids and abundant NaX (X = I, Br, Cl) has been achieved under aerobic conditions in moderate to good yields. The halodecarboxylation is shown to be an effective strategy for S-containing heteroaromatic carboxylic acid and benzoic acids with nitro, chloro and methoxyl substituents at the ortho position. A gram-scale reaction and a three-step procedure to synthesize iniparib have been performed to evaluate the practicality of this protocol. A preliminary mechanistic investigation indicates that Cu plays a vital role and a radical pathway is involved in the transformation.
- Fu, Zhengjiang,Jiang, Ligao,Zuo, Qianming,Li, Zhaojie,Liu, Yanzhu,Wei, Zhenhong,Cai, Hu
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supporting information
p. 5416 - 5421
(2018/08/12)
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- Method for synthesizing 2,5-dichloroaniline by micro-channel reactor
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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.
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Paragraph 0041; 0042; 0051; 0052; 0053; 0054; 0060; 0061
(2017/08/28)
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- A acid mechanically continuous nitration process for preparing 2, 5 - dichloro of nitrobenzene
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The invention relates to a production method for preparing 2,5-dichloronitrobenzene (DCNB) through continuous nitration, which particularly realizes the recycling of waste acids in the preparing process. The invention provides a technological program capable of recycling acids for preparing 2,5-dichloronitrobenzene (DCNB) through the continuous nitration, which is characterized in that sulfuric acid and nitric acid are prepared into a mixed acid, the mixed acid and paradichlorobenzene are simultaneously fed into a three-stages kettle (ring) type continuous reactor to carry out nitration reaction, a nitration reaction solution discharged form the third-stage kettle (ring) type continuous reactor is stood for layering so as to obtain a nitrifying oil layer and a nitrifying waste acid, and the nitrifying oil layer is subjected to alkali cleaning, water washing and light component removal so as to obtain a 2,5-DCNB finished product; paradichlorobenzene is added into the nitrifying waste acid to extract organic matters in the acid layer, residual HNO3 in the acid layer is consumed, after the extraction is completed, the obtained product is layered so as to obtain an extraction oil layer and an extracted residual waste acid, the extraction oil layer is used for next-batch nitrification, the extracted residual waste acid after being concentrated and nitric acid are prepared into the waste acid for next-batch nitrification, a small amount of emulsion layer is produced in the process of recycling, and the emulsion layer after being combined with the nitrifying oil layer is subjected to alkali cleaning and water washing.
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Paragraph 0021-0026
(2017/06/02)
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- Nitration separation method of 2,5-dichloronitrobenzene
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The invention relates to a nitration separation method of 2,5-dichloronitrobenzene. The method comprises the following steps: adding a catalyst methyl benzenesulfonic acid into a dichlorobenzene solution to carry out reaction; and after the dichlorobenzene and methyl benzenesulfonic acid are thoroughly mixed, dropwisely adding 95% concentrated nitric acid into the mixed solution, and carrying out nitration reaction at 180 DEG C for 5-7 hours to obtain the 2,5-dichloronitrobenzene crude product. By adding the catalyst methyl benzenesulfonic acid into the dichlorobenzene, the dichlorobenzene can react more sufficiently, and the reaction time is greatly shortened. The concentrated nitric acid dropwisely added into the dichlorobenzene liquid can quickly obtain dichloronitrobenzene, so the dichloronitrobenzene preparation time is shortened.
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Paragraph 0009; 0010; 0011; 0012
(2017/08/27)
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- Synthetic method of aryl halide taking aryl carboxylic acid as raw material
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A synthetic method of an aryl halide taking aryl carboxylic acid as a raw material is characterized in that a corresponding aryl halide is formed by carrying out substitution reaction on an aryl carboxylic acid compound and haloid salt MX in an organic solvent under the condition that oxygen, a silver catalyst, a copper additive and a bidentate nitrogen ligand exist, wherein M in MX represents alkali metal or alkaline earth metal, and X represents F, Cl, Br or I. Compared with a conventional aryl halide synthetic method, the synthetic method disclosed by the invention has the obvious advantages that reaction raw materials (comprising aryl carboxylic acid and MX) are cheap and easy to obtain, the using amount of a metal catalyst is small, pollution to the environment when the oxygen is used as an oxidant is the smallest, good tolerance to various functional groups on an aromatic ring is obtained, the yield is high, and the like. The synthetic method disclosed by the invention can be widely applied to synthesis in the fields of medicine, materials, natural products and the like in industry and academia.
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Paragraph 0058
(2018/01/03)
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- Decarboxylative Halogenation and Cyanation of Electron-Deficient Aryl Carboxylic Acids via Cu Mediator as Well as Electron-Rich Ones through Pd Catalyst under Aerobic Conditions
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Simple strategies for decarboxylative functionalizations of electron-deficient benzoic acids via using Cu(I) as promoter and electron-rich ones by employing Pd(II) as catalyst under aerobic conditions have been established, which lead to smooth synthesis of aryl halides (-I, Br, and Cl) through the decarboxylative functionalization of benzoic acids with readily available halogen sources CuX (X = I, Br, Cl), and easy preparation of benzonitriles from decarboxylative cyanation of aryl carboxylic acids with nontoxic and low-cost K4Fe(CN)6 under an oxygen atmosphere for the first time.
- Fu, Zhengjiang,Li, Zhaojie,Song, Yuanyuan,Yang, Ruchun,Liu, Yanzhu,Cai, Hu
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p. 2794 - 2803
(2016/04/26)
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- Computational and Experimental Studies of Phthaloyl Peroxide-Mediated Hydroxylation of Arenes Yield a More Reactive Derivative, 4,5-Dichlorophthaloyl Peroxide
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The oxidation of arenes by the reagent phthaloyl peroxide provides a new method for the synthesis of phenols. A new, more reactive arene oxidizing reagent, 4,5-dichlorophthaloyl peroxide, computationally predicted and experimentally determined to possess enhanced reactivity, has expanded the scope of the reaction while maintaining a high level of tolerance for diverse functional groups. The reaction proceeds through a novel "reverse-rebound" mechanism with diradical intermediates. Mechanistic insight was achieved through isolation and characterization of minor byproducts, determination of linear free energy correlations, and computational analysis of substituent effects of arenes, each of which provided additional support for the reaction proceeding through the diradical pathway.
- Camelio, Andrew M.,Liang, Yong,Eliasen, Anders M.,Johnson, Trevor C.,Yuan, Changxia,Schuppe, Alex W.,Houk,Siegel, Dionicio
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p. 8084 - 8095
(2015/09/01)
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- Green route for the chlorination of nitrobenzene
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A new green chlorination process of deactivated aromatics has been developed, being environmental-friendly and allowing the continuous chlorination of 1.7 kg nitrobenzene/kg catalyst per day. The triple novelty consists of using a non-conventional chlorination agent, the trichloroisocyanuric acid (TCCA, C3N3O3Cl3), along with solid acid catalysts (mainly zeolites) in a continuous flow reactor system. Different zeolites and solid acids have been tested in the chlorination of nitrobenzene, chosen as a model deactivated aromatic substrate. HUSY zeolite was found as the more promising catalyst for performing the chlorination of nitrobenzene, with good conversions (39-64%) at high selectivity toward monochlorinated products (90-99%). Finally, it is worthy to note that HUSY zeolite could be reused for at least five successive runs.
- Boltz, Marilyne,De Mattos, Márcio C.S.,Esteves, Pierre M.,Pale, Patrick,Louis, Benoit
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- Regioselective nitration of aromatics under phase-transfer catalysis conditions
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Mononitration of aromatics was performed in a two-phase system using phase-transfer catalyst. The most advantageous conditions for the nitration were determined (temperature, reaction time, the type and amount of phase transfer catalyst, nitrification strength of the nitro-sulfuric acid). From the results, a significant improvement in the selectivity and conversion of the nitration of xylene was observed: the ratio of 4-nitro-m-xylene to 2-nitro-m-xylene was unprecedented increased up to 91.3%:7.7%, the ratio of 4-nitro-o-xylene to 3-nitro-o-xylene was also increased to 71.1%:27.2%; both the conversions were over 96%.
- Wang, Peng-Cheng,Lu, Ming,Zhu, Jie,Song, Yan-Ming,Xiong, Xian-Feng
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experimental part
p. 42 - 47
(2012/01/15)
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- Oxidation of electron-deficient anilines by HOF. A route to nitro-containing compounds for molecular electronic devices
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(matrix presented) Nitroaromatic compounds for molecular electronic devices are prepared by the high-yielding oxidation of electron-deficient anilines using HOF generated in a fluorine-acetonitrile-water system.
- Dirk, Shawn M.,Mickelson, Edward T.,Henderson, Jay C.,Tour, James M.
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p. 3405 - 3406
(2007/10/03)
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- Chemistry of superacids: 35. * NO2Cl-3MXN systems: Superelectrophilic aprotic nitrating agents for deactivated aromatics
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Superelectrophilic nitration of deactivated aromatics with NO2Cl-3MXn complexes in aprotic nonpolar solvents such as CH2Cl2 makes it possible to obtain the corresponding nitro derivatives in good to almost quantitative yields under mild conditions.
- Olah,Orlinkov,Ramaiah,Oxyzoglou,Prakash
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p. 924 - 927
(2007/10/03)
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- Ozone-mediated reaction of polychlorobenzenes and some related halogeno compounds with nitrogen dioxide: A novel non-acid methodology for the selective mononitration of moderately deactivated aromatic systems
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In the presence of ozone and preferably methanesulfonic acid as catalyst, polychlorobenzenes undergo selective mononitration with nitrogen dioxide at low temperatures, giving the corresponding polychloronitrobenzenes, in most cases in nearly quantitative yields.
- Suzuki,Mori,Maeda
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p. 841 - 845
(2007/10/02)
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- Magnetic susceptibilities of organic compounds: Part V - Influence of substituents on diamagnetic susceptibilities of disubstituted and trisubstituted benzenes
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The magnetic susceptibilities of a number of triads of isomeric disubstituted benzenes have been determined, choosing the compounds in such a way that the substituents are present in the following combinations: (i) two electron-releasing substituents, (ii) a halogeno and an electron-releasing substituent, (iii) a halogeno and an electron-attracting substituent, and (iv) two halogeno substituents.The data show that for types (i), (ii) and (iv), the ortho isomers have the highest magnetic susceptibilities, the susceptibilities decreasing in the order: ortho > meta > para; for type (iii), the meta-isomers have the highest susceptibilities, the susceptibilities decreasing in the order: meta > para > ortho.The diamagnetic susceptibilities of some isomeric trisubstituted benzenes have also been determined and the data reveal that the susceptibility is the highest where the crowding of substituents is the highest (1,2,3-isomer) and lowest where the substituents are staggered and least crowded (1,3,5-isomer).Another observation made in the case of trisubstituted benzene is the applicability of a principle of additivity of their diamagnetic susceptibilities.
- Baliah, V.,Jeyanthy, J. Judith Diana
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p. 472 - 476
(2007/10/02)
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- Electrophilic Aromatic Substitution. Part 35. Chlorination of 1,3-Dinitrobenzene, 1-Chloro-2,4-dinitrobenzene, and 2,4-Dinitrotoluene with Nitric Acid and Hydrogen Chloride or Chlorine in Sulphuric Acid or Oleum
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Solutions of sulphuric acid or oleum containing HCl or Cl2 and nitric acid have been found both to chlorinate and nitrate deactivated aromatic compounds.The kinetics and products of the chlorination of 1,3-dinitrobenzene and 1-chloro-2,4-dinitrobenzene in sulphuric acid or oleum containing HCl and nitric acid at 130 deg C, and the kinetics and products of the chlorination of 2,4-dinitrotoluene at 90 deg C in sulphuric acid or oleum containing Cl2 and nitric acid, are reported. 1,3-Dinitrobenzene and 1-chloro-2,4-dinitrobenzene were predominantly chlorinated. 2,4-Dinitrotoluene gave approximately equal amounts of 6-chloro-2,4-dinitrotoluene and 2,4,6-trinitrotoluene.The results show that under these conditions, chlorination and nitration are competing electrophilic reactions, and that chlorination is less selective than nitration.Possible mechanisms for chlorination are discussed.
- Melhuish, Martin W.,Moodie, Roy B.
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p. 667 - 674
(2007/10/02)
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- Rate Constants of Series-Parallel Reactions in the Catalytic Chlorination of Nitrobenzene
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We have determined the relative rate constants of series-parallel reactions in the catalytic chlorination of nitrobenzene in the presence of ferric chloride at 60-120 deg C up to the trichloro derivative stage.
- Lebedev, V. V.,Emel'yanov, V. I.,Zetkin, V. I.
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p. 415 - 416
(2007/10/02)
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- Process for preparing o-phenylenediamine
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The invention relates to a process for preparing o-phenylenediamine. According to the invention 1,4-dichlorobenzene is nitrated to give 2,5-dichloro-nitrobenzene which is then reacted with an aqueous ammonium hydroxide solution and the 4-chloro-2-nitraniline obtained is subjected to catalytic hydrogenation to afford the end product which can thereafter be separated. The process according to the invention can be accomplished with a total yield of about 90% related to the 1,4-dichlorobenzene starting compound. o-Phenylenediamine is a valuable intermediate for instance in the synthesis of plant protecting agents and heat-resistant polymers.
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