- Synthesis method of 2, 6-dichloro-4-aminophenol
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The invention discloses a synthesis method of 2, 6-dichloro-4-aminophenol, and belongs to the field of preparation of pesticide, medicine and dye intermediates, 2, 6-dichloro-4-aminophenol is obtained by adopting paranitroaniline as a raw material through the steps of chlorination, diazonium hydrolysis, hydrogenation and the like, methanol is adopted as a solvent for chlorination, filtrate can be repeatedly used, and the use of a large amount of acid water is reduced; toluene is selected as a solvent in diazotization, diazonium liquid is directly layered after being hydrolyzed, an organic layer is separated out, water vapor distillation is not needed, and the distillation risk and energy consumption are reduced; toluene is selected as a hydrogenation solvent, and an organic layer separated after the diazonium liquid is hydrolyzed is directly hydrogenated, so that the process flow is simplified.
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- Synthesis device of 2,6-dichloro-4-amino phenol and application thereof
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A synthesis device of 2,6-dichloro-4-amino phenol comprises a first raw material storage tank group, a mixing kettle, a first raw material storage tank, a kettle type reactor, a first solid-liquid separator, a drying tower, a second raw material storage tank group, a second raw material storage tank, a tower type reactor, a second solid-liquid separator and a distillation tower; a discharging hole of the first raw material storage tank group is connected with a feeding hole of the mixing kettle; discharging holes of the mixing kettle and the first raw material storage tank are connected with a feeding hole of the kettle type reactor; a discharging hole of the kettle type reactor is connected to a feeding hole of the first solid-liquid separator; a solid-phase flow outlet of the first solid-liquid separator is connected with a feeding hole of the tower reactor, and a drying tower is arranged between the solid-phase flow outlet and the feeding hole; discharging holes of the second raw material storage tank group and the second raw material storage tank are connected with a feeding hole of the tower reactor; a discharging hole of the tower reactor is connected to a feeding hole of the second solid-liquid separator, and the distillation tower is arranged at a liquid phase flow outlet of the second solid-liquid separator. The device can efficiently and continuously synthesize 2,6-dichloro-4-amino phenol with high purity and high yield.
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Paragraph 0033; 0042; 0044-0046
(2021/06/09)
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- Synthesis method of aminophenol
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The invention provides a synthesis method of aminophenol. According to the method, by reacting nitrophenol with hydrogen under the conditions of an auxiliary agent and a solvent, an aminophenol product with high selectivity and yield can be prepared, the auxiliary agent can well control the reaction depth of nitrophenol and hydrogen, thereby inhibiting the side reaction, enhancing the purity of the final product, overcoming the problems of poor selectivity and high three-waste amount in the common hydrazine hydrate, sodium hydrosulfite and other reducing agents in the prior art, and having higher industrial application value.
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Paragraph 0077-0138
(2020/07/13)
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- Hydroxyl Assisted Rhodium Catalyst Supported on Goethite Nanoflower for Chemoselective Catalytic Transfer Hydrogenation of Fully Converted Nitrostyrenes
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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.).
- Hu, Zenan,Ai, Yongjian,Liu, Lei,Zhou, Junjie,Zhang, Gang,Liu, Hongqi,Liu, Xiangyu,Liu, Zhibo,Hu, Jianshe,Sun, Hong-bin,Liang, Qionglin
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supporting information
p. 3146 - 3154
(2019/05/10)
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- Gold-Catalyzed Dearomative Spirocyclization of N-Aryl Alkynamides for the Synthesis of Spirolactams
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A catalytic redox-neutral method for the synthesis of spirolactams proceeding through the dearomative spirocyclization of N-aryl alkynamides is reported. In contrast to stoichiometric activating agents employed for related transformations, we show that the use of 5 mol % of Au(PPh3)Cl and AgOTf in dichloroethane at 50-80 °C leads to selective spirocyclization, furnishing the products in yields of 35-87%. The substrate scope of the reaction is good, with both electron-donating and electron-withdrawing groups being tolerated around the arene ring, as well as substitution at the amide nitrogen. The identity of the para-alkoxy group on the arene ring is key to achieving selectivity for spirocyclization over alternative mechanistic pathways. While the presence of a para-methoxy group leads to trace amounts of the desired spirolactams, the para-tert-butoxy or para-hydroxy substrate analogues furnish the spirolactams in good yield with high selectivity.
- Vacala, Taylor L.,Carlson, Paul R.,Arreola-Hester, Asa,Williams, Chloé G.,Makhoul, Evana W.,Vadola, Paul A.
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p. 1493 - 1501
(2018/02/10)
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- Gold nanodots self-assembled polyelectrolyte film as reusable catalyst for reduction of nitroaromatics
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Separation of homogeneous catalyst from the reaction mixture is a crucial and difficult process in any catalytic process. To address this issue, a new class of multifunctional catalyst in the form of film was developed using a facile approach to enjoy the advantages of homogeneous catalyst with the versatility of heterogeneous catalyst. To achieve the same, methionine-capped gold nanodots (AuNDs) were self-assembled on a cationic polyelectrolyte modified glass plate for the catalytic reduction of nitro functional groups in the presence of olefinic double bond at mild conditions. Separation of this reusable catalytic film from the reaction mixture is very simple and advantageous when compared to the currently available and conventional catalytic systems. Kinetics of nitro reduction was monitored using absorption spectroscopy and the product formation was confirmed by 1H and 13CNMR analyses. Prepared AuNDs catalyst was characterized using UV-Vis spectroscopy, X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), cyclic voltammetry and atomic force microscopy (AFM) techniques. Graphical Abstract: SYNOPSIS?Colloidal gold nanoparticles are efficient catalysts for organic reactions. But the removal of homogeneous gold colloids from the reaction mixture is very difficult. To address this issue, gold nanodots were synthesized and self-assembled over polyelectrolyte film to form catalytic plates. Removal of these reusable catalytic plates from the reaction mixture is facile.[Figure not available: see fulltext.].
- Viswanathan, Perumal,Ramaraj, Ramasamy
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- Metallo-supramolecular polymer engineered porous carbon framework encapsulated stable ultra-small nanoparticles: A general approach to construct highly dispersed catalysts
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The development of a general approach for fabricating stable ultra-small heterogeneous nanocatalysts has been intensively pursued. However, issues related to complex synthesis processes and structural stability have restricted their investigation and application. Here we report a facile organometallic conjunction strategy for the large-scale fabrication of porous carbon framework encapsulated highly dispersed sub-3 nm ultra-small nanoparticles (USMNPs@PCF). This methodology is based on the convenient aldol condensation reaction to manufacture a metallo-supramolecular polymer precursor and then consequent annealing to form the target nanocomposite. This technique was successfully applied to the preparation of varieties of USMNPs@PCF, including Fe, Co, Ni, Mo, Ru, Rh, Pd and Pt. As a representative application, the PCF encapsulated sub-3 nm Pd nanoparticles demonstrated remarkable durability and efficiency for chemoselective hydrogenation of nitroarenes to their corresponding anilines under ambient conditions with low catalyst loading. All hydrogenation reactions can complete in 4 min with >99% conversion and >99% chemoselectivity. The turnover frequency (TOF) was up to 11:400 h-1 for p-nitrophenol. This work provides a general, scalable and economical route for the manufacture of sub-3 nm and highly dispersed nanocomposites, which can be used in many other important fields, such as electrochemistry, energy science and environmental protection.
- Ai, Yongjian,He, Mengqi,Zhang, Feng,Long, Yang,Li, Yunzheng,Han, Qiang,Ding, Mingyu,Sun, Hong-Bin,Liang, Qionglin
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p. 16680 - 16689
(2018/09/10)
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- Ultrafine FeCu Alloy Nanoparticles Magnetically Immobilized in Amine-Rich Silica Spheres for Dehalogenation-Proof Hydrogenation of Nitroarenes
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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.
- Bao, Hongjie,Li, Yunong,Liu, Lei,Ai, Yongjian,Zhou, Junjie,Qi, Li,Jiang, Ruihang,Hu, Zenan,Wang, Jingting,Sun, Hongbin,Liang, Qionglin
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supporting information
p. 14418 - 14424
(2018/09/12)
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- Catalytic Activities of Mono- and Bimetallic (Gold/Silver) Nanoshell-Coated Gold Nanocubes toward Catalytic Reduction of Nitroaromatics
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A new class of core-shell metallic nanostructures with tunable near-surface composition and surface morphology with excellent catalytic activity is reported. Very thin shells of metal nanoassemblies such as monolayer (Ag and Au), bilayer of Ag or Au, and AgAu alloy layer with controlled size and morphology were deposited onto a gold nanocube (AuNC) core. UV-vis absorption spectroscopy and high-resolution transmission electron microscopy analyses along with selected-area electron diffraction, energy dispersive X-ray spectroscopy, inductively coupled plasma mass spectrometer, and X-ray diffraction techniques were used to characterize the prepared core-shell nanocubes. High-angle annular dark field scanning transmission electron microscopy-energy dispersive X-ray spectroscopy mapping images were recorded for the bilayer shell and alloy layer shell in the core-shell nanostructures. Reduction of 4-nitroaniline in the presence of sodium borohydride was chosen to validate the catalytic activity of the prepared core-shell metal nanocubes. Interestingly, the AgAu alloy shell layer over the AuNC (AuNC1@Ag0.25Au0.25) showed excellent catalytic activity compared with the pristine AuNC and monolayer and bilayer core-shell nanostructures.
- Sundarapandi, Manickam,Viswanathan, Perumal,Sivakumar, Shanmugam,Ramaraj, Ramasamy
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p. 13897 - 13904
(2018/11/26)
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- Production technology of 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)benzenamine
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The invention discloses a production technology of 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)benzenamine, and relates to the technical field of chemical product production. 2,6-dichlorophenol and nitric acid are mixed to be subjected to a nitration reaction, and 2,6-dichloro-4-nitrophenol (DCNP) is obtained; the 2,6-dichloro-4-nitrophenol (DCNP) is subjected to a reduction reaction in hydrogen, and 4-amino-2,6-dichlorophenol (DCAP) is obtained; then, the 4-amino-2,6-dichlorophenol (DCAP) and tetrafluoroethylene are subjected to an addition reaction, and 3,5-dichloro-4-(1,1,2,2-tetrafluoroethoxy)benzenamine is obtained. The reaction purpose is strong, few by-products are produced, the conversion rate is high, and postprocessing is easy.
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- Synthesis method of chlorfluazuron and application of chlorfluazuron in insecticide preparation
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The invention belongs to the technical field of pesticide preparations, particularly relates to a synthesis method of chlorfluazuron and further discloses an application of chlorfluazuron in insecticide preparation. According to the synthesis method of chlorfluazuron, chlorfluazuron is prepared from 2,3-dichloro-5-(trifluoromethyl)pyridine, 2,6-dichloro-4-aminophenol and 2,6-difluorobenzoyl isocyanate as synthetic raw materials and N,N-dimethylacetamide as a reaction solvent on the basis of a conventional synthesis route in the prior art; under the action of a ZSM molecular sieve based catalyst, not only can synthesis of chlorfluazuron be realized, but also a reaction can be performed with the same reaction solvent, so that the problem of complicated process caused by the fact that solvents are required to be recovered step by step during two-step synthesis of chlorfluazuron in the prior art is solved; compared with the technology in the prior art, the synthesis method of chlorfluazuron has the advantages that the synthesis yield of products is further increased and product content is higher.
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- 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
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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.
- Zhou, Junjie,Li, Yunong,Sun, Hong-Bin,Tang, Zhike,Qi, Li,Liu, Lei,Ai, Yongjian,Li, Shuang,Shao, Zixing,Liang, Qionglin
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supporting information
p. 3400 - 3407
(2017/07/28)
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- Highly selective hydrogenation of aromatic chloronitro compounds to aromatic chloroamines with ionic-liquid-like copolymer stabilized platinum nanocatalysts in ionic liquids
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Platinum nanoparticles (PtNPs stabilized by an ionic-liquid-like-copolymer (IP) immobilized in various ionic liquids (ILs)) effectively catalyze the selective hydrogenation of aromatic chloronitro compounds to aromatic chloroamines, a reaction of considerable commercial significance. The preparation of 2,4-dichloro-3-aminophenol (DAP) has been primarily studied due to its important industrial applications. DAP is usually prepared from 2,4-dichloro-3-nitrophenol (DNP) by reduction with hydrogen using Ni- or Pt-based catalysts. Compared to reactions in molecular (organic) solvents, the ILs system provides superior selectivity with functionalized ILs containing an alcohol group demonstrating the best recyclability, and ultimately achieving a turnover number of 2025 which is 750 fold higher than Raney nickel catalyst. A universal catalyst-ionic liquid system for the conversion of aromatic chloronitro compounds to aromatic chloroamines was also established. TEM, XPS, IR spectroscopy were used to characterize the morphology of the nanocatalysts allowing their structure to be correlated to their activity.
- Yuan, Xiao,Yan, Ning,Xiao, Chaoxian,Li, Changning,Fei, Zhaofu,Cai, Zhipeng,Kou, Yuan,Dyson, Paul J.
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experimental part
p. 228 - 233
(2011/03/17)
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- Theory and practice of enzyme bioaffinity electrodes. Direct electrochemical product detection
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The use of enzyme labeling techniques to convert biorecognition events into high sensitivity electrochemical signals may follow two different strategies. One, in which the current is the electrocatalytic response of a redox couple serving as cosubstrate to a redox enzyme label and another that consists in the detection of an electrochemically active product of the enzyme label. The theoretical relationships that link, in the latter case, the electrochemical current response to the amount of recognized labeled target analyte are established for steady-state diffusion-convection chronoamperometric regimes. Two governing parameters thus emerge. One measures the Michaelis-Menten competition in the enzyme kinetics. The other characterizes the competition between the enzymatic kinetics and the diffusion of the substrate. The electrochemical response is finally related to the labeled target analyte concentration in solution through the recognition isotherm. The direct electrochemical product detection thus provides a route to the characteristics of the recognition isotherm, which serves as a calibration curve in analytical applications. The establishment of further theoretical relationships allows one to surmise the increase in sensitivity that may be obtained by using cyclic voltammetry instead of steady-state chronoamperometry in standard electrochemical cells or by accumulation of the enzyme-product in cells of small volume/surface ratios. The theoretical predictions are tested with the example of the avidin-biotin recognition process in a system that involves alkaline phosphatase as enzyme label and 4-amino-2,6-dichlorophenyl phosphate as substrate, generating 4-amino-2,6-dichlorophenol as electrochemically active product. The advantages of the dichlorosubstitution are discussed. The theoretical analysis is a requisite for a rational and realistic discussion of the analytical performances of the steady-state chronoamperometric and cyclic voltammetric approaches. These are shown to compare favorably with the best heterogeneous bioaffinity assays so far reported.
- Limoges, Benoit,Marchal, Damien,Mavre, Francois,Saveant, Jean-Michel,Schoellhorn, Bernd
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p. 7259 - 7275
(2008/12/21)
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- Hair colouring and conditioning compositions
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A hair colouring and conditioning composition comprising: (a) a hair colouring agent; and (b) a hair conditioning agent; wherein the composition provides an Average Combing Index Value of greater than 1.2 as measured by the Combing Technical Test Method. The products can provide excellent hair colouring together with excellent conditioning, reduced hair damage, brittleness and dryness, and is convenient and easy to use.
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- Hair conditioning compositions and their use in hair colouring compositions
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The present invention relates to a hair care composition comprising a aminofunctional polysiloxane having a specified average effective particle size which provides improved durable conditioning particularly when utilised in conjunction with a hair colouring composition.
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- Hydrogenation of halonitrobenzenes without dehalogenation
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A method for inhibiting dehalogenation of fluorinated and chlorinated benzenoid nitro compounds during catalytic hydrogenation to make the corresponding substituted anilines by conducting the hydrogenation reaction in the presence of an acidic catalytic medium.
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- GIBBS REACTION. PART 1. REDUCTION OF BENZOQUINONE N-CHLOROIMINES TO BENZOQUINONE IMINES
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The behaviour of benzoquinone N-chloroimines under neutral, acidic, and basic conditions has been studied.Although these compounds are stable under neutral conditions they are hydrolysed in acidic solution to the corresponding benzoquinone derivatives.In the presence of base and alcohols, they are reduced to benzoquinone imines.Kinetic investigation of the reaction suggested an ionic mechanism, in which cleavage of the Cα-H bond of the alcohol is the rate-determining step.
- Pallagi, Istvan,Dvortsak, Peter
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p. 105 - 110
(2007/10/02)
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