3964-52-1Relevant articles and documents
Catalytic Activities of Mono- and Bimetallic (Gold/Silver) Nanoshell-Coated Gold Nanocubes toward Catalytic Reduction of Nitroaromatics
Sundarapandi, Manickam,Viswanathan, Perumal,Sivakumar, Shanmugam,Ramaraj, Ramasamy
, p. 13897 - 13904 (2018)
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.
Nitrogen-doped carbon supported iron oxide as efficient catalysts for chemoselective hydrogenation of nitroarenes
Xu, Shaodan,Yu, Deqing,Liao, Shangfu,Ye, Tao,Sheng, Huadong
, p. 96431 - 96435 (2016)
Chemoselective hydrogenation has been widely used in the production of fine chemicals, and developing heterogeneous catalysts with high activity and chemoselectivity is always a challenging topic. Herein, we report a new type of catalysts synthesized from biomass-derived chitosan and non-noble iron, which is denoted as nitrogen-doped carbon supported iron (Fe/N-C). TEM and XRD characterization indicate the presence of iron species. Interestingly, the Fe/N-C catalysts exhibited excellent catalytic performances in the hydrogenation of nitroarenes, and excellent yields of target aniline products could be obtained under industrially viable conditions.
Pd-Co catalysts prepared from palladium-doped cobalt titanate precursors for chemoselective hydrogenation of halonitroarenes
Bustamante, Tatiana M.,Dinamarca, Robinson,Torres, Cecilia C.,Pecchi, Gina,Campos, Cristian H.
, (2019/12/24)
Bimetallic Pd-Co catalysts supported on the mixed oxides CoTiO3-CoO-TiO2 (CTO) were synthesized via the thermal reduction of Pd-doped cobalt titanates PdxCo1-xTiO3 and evaluated for the chemoselective hydrogenation of halonitroarenes to haloarene-amines. The nominal Pd mass percentage of the Pd-Co/CTO systems was varied from 0.0 to 0.50. After the thermal reduction of PdxCo1-xTiO3 at 500 °C for 3 h, Pd was completely reduced and Co was partially reduced, producing a mixture of ionic Co, metallic Co, and TiO2-rutile species to give the supported bimetallic catalysts. The metallic cobalt content increased with the Pd content of the precursor. The catalytic activity toward 4-chloronitrobenzene increased with the Pd content; however, >0.1 mass% Pd decreased the chemoselectivity toward 4-chloroaniline due to the formation of the hydrodehalogenation product—aniline. The 0.1Pd-Co/CTO system was used as a model catalyst to produce haloarene-amine building blocks for linezolid, loxapine, lapatinib, and sorafenib with >98% conversion, 96% chemoselectivity, and no hydrohalogenation products. Finally, recycling tests of the 0.1Pd-Co/CTO catalyst showed loss of activity and selectivity during the third cycle due to catalyst deactivation. Regeneration treatments, every two catalytic cycles, allowed six operation cycles without loss of chemoselectivity and only a slight decrease in catalytic activity during the last cycle.
Fe-Catalyzed Amination of (Hetero)Arenes with a Redox-Active Aminating Reagent under Mild Conditions
Liu, Jianzhong,Wu, Kai,Shen, Tao,Liang, Yujie,Zou, Miancheng,Zhu, Yuchao,Li, Xinwei,Li, Xinyao,Jiao, Ning
supporting information, p. 563 - 567 (2017/01/18)
A novel and efficient Fe-catalyzed direct C?H amination (NH2) of arenes is reported using a new redox-active aminating reagent. The reaction is simple, and can be performed under air, mild, and redox-neutral conditions. This protocol has a broad substrate scope and could be used in the late-stage modification of bioactive compounds. Mechanistic studies demonstrate that a radical pathway could be involved in this transformation.
