نتایج جستجو برای: hydrogenation mechanism

تعداد نتایج: 573485  

Journal: :Topics in current chemistry 2014
Yan-Mei He Feng-Tao Song Qing-Hua Fan

Transition metal-catalyzed asymmetric hydrogenation of heteroaromatic compounds is undoubtedly a straightforward and environmentally friendly method for the synthesis of a wide range of optically active heterocyclic compounds, which are widespread and ubiquitous in naturally occurring and artificial bioactive molecules. Over the past decade, a number of transition metal (Ir, Rh, Ru, and Pd) cat...

2001
J. J. M. Mars

The dehydrogenation of piperidine has been studied and found to have an order of -1.5 with respect to the hydrogen partial pressure. By combining these results with those obtained for pyridine hydrogenation on the same catalyst a complete rate equation for piperidine dehydrogenation together with the stoichiometric number of the rate-determining step of these reactions could be derived. This nu...

Journal: :Faraday Discussions 2021

An alternative reaction mechanism combined with preferential perpendicular adsorption make non-noble metals chemoselective catalysts for nitroarene hydrogenation.

2016
Marc Renom-Carrasco Piotr Gajewski Luca Pignataro Johannes G. de Vries Umberto Piarulli Cesare Gennari Laurent Lefort

Herein we describe a new methodology for the asymmetric hydrogenation (AH) of 2-substituted pyridinium salts. An iridium catalyst based on a mixture of a chiral monodentate phosphoramidite and an achiral phosphine was shown to hydrogenate N-benzyl-2-arylpyiridinium bromides to the corresponding N-benzyl-2-arylpiperidines with full conversion and good enantioselectivity. The mechanism of the rea...

2001
Ryoji Noyori Masatoshi Koizumi Dai Ishii Takeshi Ohkuma

RuCl2(phosphine)2(1,2-diamine) complexes, coupled with an alkaline base in 2-propanol, allows for preferential hydrogenation of a C=O function over coexisting conjugated or nonconjugated C=C linkages, a nitro group, halogen atoms, and various heterocycles. The functional group selectivity is based on the novel metal–ligand bifunctional mechanism. The use of appropriate chiral diphosphines and d...

Journal: :Proceedings of the Japan Academy 1977

2016
S. Gerke H.-W. Becker D. Rogalla F. Singer N. Brinkmann S. Fritz A. Hammud P. Keller D. Skorka D. Sommer C. Weiß S. Flege G. Hahn B. Terheiden

Amorphous silicon (a Si) is common in the production of technical devices and can be deposited by several techniques. In this study intrinsic and doped, hydrogen less amorphous silicon films are RF magnetron sputter deposited and post hydrogenated in a remote hydrogen plasma reactor at a temperature of 370 °C. Secondary ion mass spectrometry of a boron doped (p) a Si layer shows that the concen...

Journal: :journal of nanostructures 2014
e. esmaeili a. rashidi

in the present study, tin-promoted pd/mwnts nanocatalystwas synthesized via polyol technique for application in hydrogenation of high-concentrated acetylene feedstocks. tem images showed a restricted distribution of nanoparticles in the range of 3-5 nm. the results indicated that nanoparticles sizes were resistant to further catalyst deactivation. xrd patterns signified alloying between pd and ...

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