101-13-3Relevant articles and documents
Size-controllable palladium nanoparticles immobilized on carbon nanospheres for nitroaromatic hydrogenation
Lu, Yong-Ming,Zhu, Hai-Zhou,Li, Wei-Gu,Hu, Bo,Yu, Shu-Hong
, p. 3783 - 3788 (2013)
In this paper, monodisperse Pd nanocrystals were immobilized on previously reported carbon nanospheres via in situ adsorption and reduction. In this protocol, no excess reductant and capping reagents were necessary, which made the surface of the as-prepared nanocatalysts very clean. Using sodium tetrachloropalladate(ii) as the metal precursor yielded palladium nanocrystals with a size around 5 nm regardless of the metal loading, while the use of palladium chloride resulted in a size increase to 18.1 nm. Moreover, the additives used during preparation have been proven to be of great importance in controlling the average particle size. It was suggested that the pattern of the adsorbed palladium ions or the surface environment of support was greatly influenced. Strong adsorption of the palladium ions on the carbon spheres led to a decrease in size. The nanocrystals exhibited excellent catalytic activity for transfer hydrogenation under ambient conditions. The conversion was 83.1% to 100% for several nitroaromatics with moderate to excellent selectivity. More importantly, these nanocatalysts are promising for renewable catalysis owing to their sustainable support, green catalyst fabrication and ease of handling.
Palladium Nanoparticles on Silica Nanospheres for Switchable Reductive Coupling of Nitroarenes
Lakshminarayana, Bhairi,Manna, Arun Kumar,Satyanarayana,Subrahmanyam, Ch.
, p. 2309 - 2321 (2020/02/18)
Abstract: In this study, we synthesized a robust and sustainable Pd/SiO2 nanospheres catalyst. Further, its catalytic activity was demonstrated for the direct reductive coupling of nitroarenes under mild conditions. While the reaction with Pd nanoparticles on other supporting materials such as modified carbon materials and TiO2, under similar conditions, resulted formation of amines exclusively. Therefore, it was confirmed that the SiO2 was found to be the best supporting material towards the selective reductive coupling of nitroarenes. Also, the catalyst could be recycled up to five cycles with a marginal loss of product yield ( 2% yield). Graphic Abstract: [Figure not available: see fulltext.].
The synthesis of anilines or azoxybenzenes from the reduction of nitrobenzenes in basic alcoholic media
Prato, Maurizio,Quintily, Ugo,Scapol, Lucia,Scorrano, Gianfranco
, p. 99 - 102 (2007/10/02)
Reduction of substituted nitrobenzenes in alkaline alcoholic solutions affords, depending on the experimental conditions used, either anilines or azoxybenzenes in good yields.In the presence of a methylketone, such as acetophenone, the reaction of nitroarenes with aqueous KOH in 2-propanol provides the corresponding anilines in high yields (80-90 percent).On the other hand, when the reaction is carried out in the CH3OH/toluene/KOH system, in the absence of methylketones, the azoxyderivatives are isolated in 70-90 percent yield.