586-96-9Relevant articles and documents
An effective medium of H2O and low-pressure CO2 for the selective hydrogenation of aromatic nitro compounds to anilines
Meng, Xiangchun,Cheng, Haiyang,Fujita, Shin-Ichiro,Yu, Yancun,Zhao, Fengyu,Arai, Masahiko
, p. 570 - 572 (2011)
Chemoselective hydrogenation of water-insoluble aromatic nitro compounds can be achieved over Ni catalysts in a H2O-compressed CO2 system at 35-50 °C without using any environmentally harmful solvent. The effective CO2 pressure is much lower than the critical pressure of CO2. The hydrogenation of nitro group should be the rate-determining step. The Royal Society of Chemistry.
Ethylenediamine-assisted solvothermal synthesis of one-dimensional Cd xZn(1-x)S solid solutions and their photocatalytic activity for nitrobenzene reduction
Wei, Hongwei,Jiang, Hechun,Zheng, Zhen,Zhao, Quanqin,Wu, Qingyin,Zhan, Jinhua
, p. 1352 - 1356 (2013)
A series of one-dimensional CdxZn(1-x)S semiconductor alloys were prepared via a hydrothermal method with the assistance of ethylenediamine at 180 °C for 12 h. The products were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption/desorption and Fourier transform infrared techniques. With the value of x increased, the band gap of CdxZn(1-x)S semiconductor alloys gradually decreased indicating that catalysts were exchanged to visible-light response. Photocatalytic reduction results showed that Cd0.73Zn0.27S exhibited the highest photocatalytic activity toward photo production of aniline via nitrobenzene reduction under visible irradiation respectively. The reaction mechanism was also discussed.
Dimeric assemblies of lanthanide-stabilised dilacunary Keggin tungstogermanates: A new class of catalysts for the selective oxidation of aniline
Trautwein, Guido,El Bakkali, Bouchra,Alca?iz-Monge, Juan,Artetxe, Be?at,Reinoso, Santiago,Gutiérrez-Zorrilla, Juan M.
, p. 110 - 117 (2015)
In this work we demonstrate the efficiency of some dimeric [Ln4(H2O)6(β-GeW10O38)2]12- anions composed of lanthanide-stabilised dilacunary Keggin tungstogermanate fragments (ββ-Ln4, Ln = Dy, Ho, Er, Tm) as heterogeneous catalysts for the organic phase oxidation of aniline with hydrogen peroxide. The results obtained evidence total conversion of aniline at room temperature, as well as full selectivity towards nitrosobenzene, and the catalysts are able to retain both their activity and selectivity after several runs. Peroxopolyoxometalate intermediaries have been identified as the catalytically active species during the aniline-to-nitrosobenzene oxidation process.
One-pot synthesis of aluminum oxyhydroxide matrix-entrapped Pt nanoparticles as an excellent catalyst for the hydrogenation of nitrobenzene
Fan, Guangyin,Wang, Yinhu,Wang, Chenyu
, p. 10997 - 11002 (2014)
Aluminum oxyhydroxide matrix-entrapped Pt nanoparticles (Pt/AlO(OH)) were synthesized via a one-pot procedure, by the reduction of Pt4+ followed by the hydrolysis of Al(O-sec-Bu)3. Small and well-dispersed Pt nanoparticles were entrapped into an aluminum oxyhydroxide matrix and confirmed by TEM characterization. FTIR analysis indicated that the Pt/AlO(OH) catalyst had a large amount of surface hydroxyl groups, which potentially improves its dispersibilty in aqueous solution. The as-prepared catalyst was used for the hydrogenation of nitrobenzene to aniline at 30 °C and atmospheric hydrogen pressure. Compared with other alcohol-water media, the hydrogenation reaction in a methanol-water medium exhibited a maximum turnover frequency (TOF) of 3620 h-1. A complete conversion of nitrobenzene with a selectivity of 99.0% was obtained with an increase of time to 150 min.
Fabrication of hybrid mesoporous TiO2-SiO2(Et) supported Ni nanoparticles: An efficient and air/water stable catalyst
Li, Wei,Cheng, Haiyang,Lin, Weiwei,Liang, Guanfeng,Zhang, Chao,Zhao, Fengyu
, p. 214 - 221 (2016)
We prepared a series of mesostructured Ni/TiO2-SiO2(Et) hybrid catalysts with highly dispersed Ni nanoparticles and incorporated ethane-bridged organosilica moieties. Ni/TiO2-SiO2(Et) showed high activity in the hydrogenation of nitrobenzene in water, and it could be recycled for several times with a constant activity and selectivity. It was confirmed that Ni/TiO2-SiO2(Et) catalyst is of hydrophobicity as the ethane-bridged organosilica fragments were incorporated into the mesoporous framework, and so the Ni active species was protected without contacting with water to form the inactive Ni species. In particularly, the Ni/TiO2-SiO2(Et) catalyst was air-stable, it could remain good activity after being exposed to air for a week. Accordingly, this work developed a kind of hydrophobic Ni catalyst with high stability to water and air, which is expected to have a wide application in the hydrogenation reactions.
Radical Cations of Nitroso Derivatives. A Radiation-chemical and Electron Spin Resonance Study
Chandra, Harish,Keeble, David J.,Symons, Martyn C. R.
, p. 609 - 616 (1988)
Exposure of dilute solutions containing nitrosobenzene in trichlorofluoromethane to 60Co γ-rays at 77 K gave the corresponding radical cation, characterised by e.s.r. spectroscopy.The results confirm the interpretation of liquid-phase data assigned to this cation, which showed that loss is from an in-plane ?-orbital localised on nitrogen and oxygen, rather than from the aromatic ?-system.However, solutions containing the t-butyl derivative in equilibrium with its dimer, (Me3CNO)2, gave primarily the dimer cation, (Me3CNO)2+, with possible traces of the monomer cation.The e.s.r. data for the latter resemble those for the nitrosobenzene cation, whereas results for the dimer cation suggest that loss is from a ?-type orbital with very low spin density on the two equivalent nitrogen atoms.
Kinetics and mechanism of the enhanced reductive degradation of nitrobenzene by elemental iron in the presence of ultrasound
Hoffmann,Hung,Ling
, p. 1758 - 1763 (2000)
The degradation of nitrobenzene (NB) and aniline (AN) were facilitated by using sonolysis, reduction by Fe0 and a combination of the two processes. The rates of NB reduction by Fe0 increased in the presence of ultrasound. The first-order rate constant for NB degradation by ultrasound was 1.8 x 10-3/min. The rate was considerably faster in the presence of Fe0. The similar degradation rates for AN in each system indicated that the sonication process was unaffected by the presence of Fe0. The rate enhancements for the NB degradation can be explained chiefly by the continuous cleaning and chemical activation of the Fe0 surfaces by acoustic cavitation and to accelerated mass transport rates of reactants, intermediates and products between the solution phase and the Fe0 surface. The relative concentrations of nitrosobenzene and AN, the main reaction intermediates produced by Fe0 reduction, were significantly changed in the presence of ultrasound.
Continuous proline catalysis via leaching of solid proline
Opalka, Suzanne M.,Longstreet, Ashley R.,Tyler McQuade
, p. 1671 - 1679 (2011)
Herein, we demonstrate that a homogeneous catalyst can be prepared continuously via reaction with a packed-bed of a catalyst precursor. Specifically, we perform continuous proline catalyzed α-aminoxylations using a packed-bed of L-proline. The system relies on a multistep sequence in which an aldehyde and thiourea additive are passed through a column of solid proline, presumably forming a soluble oxazolidinone intermediate. This transports a catalytic amount of proline from the packed-bed into the reactor coil for subsequent combination with a solution of nitrosobenzene, affording the desired optically active α-aminooxy alcohol after reduction. To our knowledge, this is the first example in which a homogeneous catalyst is produced continuously using a packedbed. We predict that the method will not only be useful for other L-proline catalyzed reactions, but we also foresee that it could be used to produce other catalytic species in flow.
Catalytic Teflon AF-2400 membrane reactor with adsorbed ex situ synthesized Pd-based nanoparticles for nitrobenzene hydrogenation
Venezia, Baldassarre,Panariello, Luca,Biri, Daniel,Shin, Juhun,Damilos, Spyridon,Radhakrishnan, Anand N.P.,Blackman, Chris,Gavriilidis, Asterios
, p. 104 - 112 (2021)
Among the unconventional approaches of supporting catalyst nanoparticles, the layer-by-layer assembly of polyelectrolyte multilayers for nanoparticle adsorption represents an easy and convenient method. It enables the deposition of singularly adsorbed nanoparticles and prevents them from aggregating. In this work, polydopamine was grafted onto the internal surface of a Teflon AF-2400 tubular membrane, known for its excellent permeability to light gases and inertness to chemicals. Poly(acrylic acid) and poly(allylamine hydrochloride) were sequentially adsorbed onto the modified surface of the membrane. Ex situ synthesized spherical, cubical, truncated octahedral palladium or dendritic platinum-palladium nanoparticles were then incorporated. The catalytic membranes were assembled in a tube-in-tube configuration and tested over 6 h of continuous nitrobenzene hydrogenation with molecular hydrogen. Stable conversion was observed for the truncated octahedral and dendritic nanoparticles, while a progressive deactivation occurred for the other nanoparticles. Due to their small size, the 3.7 nm spherical nanoparticles exhibited the highest reaction rate, 629molreactant/(molcatalyst?h), while the cubical nanoparticles showed the highest turnover frequency, ～3000 h?1. The reactor concept developed in this work demonstrates how such a design can serve as a platform for conducting continuous multiphase catalytic reactions in flow using singularly adsorbed and finely tuned nanoparticles. The small volume of pressurized gas present in the tube-in-tube reactor offers improved process safety compared to a batch process, while the Teflon AF-2400 membrane provides control over the gas permeation during reaction.
The Active Sites of Manganese- and Cobalt-Containing Catalysts in the Selective Gas Phase Reduction of Nitrobenzene
Maltha, A.,Kist, H. F.,Brunet, B.,Ziolkowski, J.,Onishi, H.,et al.
, p. 356 - 363 (1994)
The active sites of the spinels Mn3O4 and Co3O4 in the selective reduction of nitrobenzene to nitrosobenzene have been investigated, by total and partial substitution of Mnn+ (Con+) ions in tetrahedral position and/or Mnn+ (Con+) ions in octahedral position by redox-inactive ions.Investigation of the catalytic activities of the totally substituted manganese spinel ZnMn2O4 and that of the totally substituted cobalt spinels CoAl2O4 and ZnCo2O4 showed that the manganese and cobalt ions in octahedral position were responsible for the activity of the reaction.MnAl2O4, however, also showed some activity for the selective reduction of nitrobenzene, which should be due to surface enrichment and/or oxidative transfer of manganese from tetrahedral sites to octahedral sites.XRD results of the partially substituted spinels MnxZn1-xAl2O4 showed that was a linear correlation between the manganese concentration expressed by x and the lattice constant.Morever, each sample showed segregation of Al2O3; again there was a linear correlation between x in certain series of MnxZn1-xAl2O4 and the amount of free Al2O3.This points to an oxidative transfer of manganese from tetrahedral sites to octahedral sites.XPS showed that the concentration of manganese in the surface layers corresponded roughly to the value x, but the concentration of zinc in the surface layers was much smaller than expected.The catalytic activities of the MnxZn1-xAl2O4 series of catalysts are larger than would be expected from the result on ZnMnO4 and ZnCo2O4.
