نتایج جستجو برای: hydrogenation
تعداد نتایج: 8711 فیلتر نتایج به سال:
High-pressure torsion (HPT) is widely used as a severe plastic deformation technique to create ultrafine-grained structures with promising mechanical and functional properties. Since 2007, the method has been employed to enhance the hydrogenation kinetics in different Mg-based hydrogen storage materials. Recent studies showed that the method is effective not only for increasing the hydrogenatio...
The effect of hydrogenation on the intensity evolution of ZnO single crystal under electron beam irradiation was investigated by cathodoluminescence (CL). Without hydrogenation, the ultraviolet (UV) emission for O-face decreases exponentially and reaches a constant value with e-beam irradiation, while that for Zn-face once increases and then decreases. The hydrogenation significantly increases ...
We report on a new class of P-O monophosphite ligands (designated 3a-k) with a double six-membered-ring backbone onto which are attached additional groups and on applications of their Rh complexes in the hydrogenation of enamides, alpha-dehydroamino acid esters, dimethyl itaconate, and beta-(acylamino)acrylates. Our results demonstrate that the Rh complexes with ligands 3a-k exhibit high enanti...
Bilayer Mg/Co and Mg/Mn (700nm) thin films were prepared using thermal evaporation method at pressure10 torr at room temperature. The films were rapid thermal annealed (RTA) using halogen lamp to get a homogeneous structure of thin films. The hydrogen gas was introduced in hydrogen chamber, where samples were kept at different pressure from 10 to 40 psi of H2 for thirty minutes. The conductivit...
Towards the development of a useful mechanism for hydrogen storage, we have studied the hydrogenation of single-walled carbon nanotubes with atomic hydrogen using core-level photoelectron spectroscopy and x-ray absorption spectroscopy. We find that atomic hydrogen creates C-H bonds with the carbon atoms in the nanotube walls, and such C-H bonds can be completely broken by heating to 600 degrees...
A mild and general iridium-catalyzed, highly enantioselective hydrogenation of sterically hindered N-arylimines with a new H(8)-BINOL-derived phosphine-phosphoramidite ligand has been developed. The present catalytic system features high turnover numbers (up to 100000) and good to perfect enantioselectivities (up to 99% ee) for the hydrogenation of a variety of sterically hindered N-arylimines.
Adding a small amount of fully dispersed Pt entities onto the Au surface in Au/SiO(2) catalyst is found to be an efficient approach to improve the catalytic activity of Au (up to 70-fold) for the hydrogenation of α,β-unsaturated carbonyl compounds, without alternating its selectivity towards C=O or C=C bond hydrogenation.
The addition of carbon dioxide and water enhances acetophenone hydrogenation activity over an activated carbon-supported palladium catalyst, and 1-phenylethanol can be easily recovered without distillation and neutralization. Two liquid phases (water and acetophenone) are indispensable for enhancement of the hydrogenation rate.
Ruthenium nanoparticles (RuNPs) were prepared through the hydrogenation of [Ru(COD)(COT)] (COD = 1,5-cyclooctadiene, COT = 1,3,5-cyclooctatriene) in the presence of diphosphites derived from carbohydrates as stabilizing agents, and interestingly, structural modifications of the diphosphite backbone were found to influence nanoparticle size and dispersity, as well as their catalytic activity in ...
A novel non-noble Co@C-N catalytic system has been developed for catalytic transfer hydrogenation reactions. Co@C-N was found to be highly active and selective in the hydrogenation of a variety of unsaturated bonds with isopropanol in the absence of base additives.
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