نتایج جستجو برای: hydrogenation
تعداد نتایج: 8711 فیلتر نتایج به سال:
The catalytic activity of palladium toward selective hydrogenation of hydrocarbons depends on the partial pressure of hydrogen. It has been suggested that the reaction proceeds selectively toward partial hydrogenation only when a carbon-rich film is present at the metal surface. On the basis of first-principles simulations, we show that carbon can dissolve into the metal because graphite format...
The pressure hydrogenation capabilities of the iridium pincer complexes IrH2Cl[((i)Pr2PC2H4)2NH] (1) and IrH3[((i)Pr2PC2H4)2NH] (2) are described and compared to related results obtained previously in transfer hydrogenation. Complex 1 was shown to act as a convenient air-stable entry point to the active catalyst 2, in the presence of base and hydrogen gas. The catalysts are active in a range of...
The enantioselective catalytic hydrogenation of N-(3,4-dihydronaphthalen-2-yl) amides (1) with rhodium catalysts bearing phosphine-phosphite ligands 4 has been studied. A wide catalyst screening, facilitated by the modular structure of 4, has found a highly enantioselective catalyst for this reaction. This catalyst gives a 93% ee in the hydrogenation of 1a and also produces high enantioselectiv...
Bond-Order Conservation-Morse Potential (BOC-MP) method is used to carry out the calculationon the CO2+ H20 system. One of the best catalysts for methanol synthesis in catalytic reductionof CO2 with H2O is Cu/ZnO/A1203 whose surface is supported by with some amount of Pd orGa. Reduction of CO2 with H20 on Cu will result in methanol formation; while on Ni will lead tomethane formation. In the me...
Optically active alcohols are important building blocks in the synthesis of fine chemicals, pharmaceuticals, agrochemicals, flavors and fragrances as well as functional materials (Arai & Ohkuma, 2011; Klingler, 2007). Furthermore, molecular hydrogen is without doubt the cleanest reducing agent, with complete atom efficiency. Therefore, the catalytic, asymmetric hydrogenation (AH) of prochiral k...
The review presents a concise discussion of reports on hydrogenation of N-containing heteroaromatic compounds in relation to the hydrodenitrogenation process (HDN), along with hydrogenation mechanisms of the most representative examples of the compounds studied. The influence of electronic properties of aromatic structures, with the special emphasis on the resonance stabilization energies and t...
The asymmetric transfer hydrogenation of imines was performed with the use of a polymer-immobilized chiral catalyst. The chiral catalyst, prepared from crosslinked polystyrene-immobilized chiral 1,2-diamine monosulfonamide, was effective in the asymmetric transfer hydrogenation of N-benzyl imines in CH(2)Cl(2) to give a chiral amine in high yield and good enantioselectivity. Furthermore, an amp...
The understanding of hydrogen attachment to carbonaceous surfaces is essential to a wide variety of research fields and technologies such as hydrogen storage for transportation, precise localization of hydrogen in electronic devices and the formation of cosmic H2. For coronene cations as prototypical Polycyclic Aromatic Hydrocarbon (PAH) molecules, the existence of magic numbers upon hydrogenat...
The pursuit of modern sustainable chemistry has stimulated the development of innovative catalytic processes that enable chemical transformations to be performed under mild and clean conditions with high efficiency. Herein, we report that gold nanoparticles supported on TiO(2) catalyze the chemoselective hydrogenation of functionalized quinolines with H(2) under mild reaction conditions. Our re...
Two representative Walphos analogues with an achiral 2,2″-biferrocenediyl backbone were synthesized. These diphosphine ligands were tested in the rhodium-catalyzed asymmetric hydrogenation of several alkenes and in the ruthenium-catalyzed hydrogenation of two ketones. The results were compared with those previously obtained on using biferrocene ligands with a C2-symmetric 2,2″-biferrocenediyl b...
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