نتایج جستجو برای: hydrogenation
تعداد نتایج: 8711 فیلتر نتایج به سال:
Platinum, palladium, and copper catalysts supported on precipitated silica have been studied for the hydrodeoxygenation and hydrogenation of 2-methyl-2-pentenal in the 200–400 C temperature range. The activity follows the order Pt > Pd > Cu. It has been found that at low temperatures, Pt and Pd are primarily active for the hydrogenation of the C@C bond to make 2-methyl-pentanal, with some decar...
We report a synergistic effect involving hydrogenation and nitridation cotreatment of TiO(2) nanowire (NW) arrays that improves the water photo-oxidation performance under visible light illumination. The visible light (>420 nm) photocurrent of the cotreated TiO(2) is 0.16 mA/cm(2) and accounts for 41% of the total photocurrent under simulated AM 1.5 G illumination. Electron paramagnetic resonan...
The use of non-supported Fe nanoparticles in the hydrogenation of unsaturated C-C bonds is a green catalytic concept at the frontier between homogeneous and heterogeneous catalysis. Iron nanoparticles can be obtained by reducing Fe salts with strong reductants in various solvents. FeCl(3) reduced by 3 equivalents of EtMgCl forms an active catalyst for the hydrogenation of a range of olefins and...
Supported gold nanoparticles have recently been shown to possess intriguing catalytic activity for hydrogenation reactions, particularly for selective hydrogenation reactions. However, fundamental studies that can provide insight into the reaction mechanisms responsible for this activity have been largely lacking. In this tutorial review, we highlight several recent model experiments and theore...
Supported Ni catalysts prepared under different conditions, for liquid phase hydrogenation of adiponitrile (ADN) to 6-aminocapronitrile (ACN) and hexamethyenediamine (HMD), were investigated. The highly reactive imine intermediate can form condensation byproducts with primary amine products (ACN and HMD), which decreased the yield coefficient of primary amines. The catalysts support, condition ...
We present a model for the hydrogenation states of Polycyclic Aromatic Hydrocarbons (PAHs) in the diffuse interstellar medium. First, we study the abundance of hydrogenation and charge states of PAHs due to photo-ionization, photodissociation in the interstellar UV field, electron recombination and chemical reactions between PAH cations and H or H2. For PAH cations, we find that the dehydrogena...
The reaction of copper stearate with triethylaluminurn (TEAL) formed a soluble catalyst that promoted the selective hydrogenation of the linolenyl groups in soybean oil. This homogeneous catalyst was more active than copper-chromite. The activity was enhanced by the addition of silica, alumina or titania. Ethyl alcohol accelerated the hydrogenation when it was added in small amounts and retarde...
Catalytic hydrogenation of 3,5-bis-arylidenetetramic acids, known for their biological activity, has been developed. The chemoselective ruthenium-catalyzed reduction of the exocyclic carbon-carbon double bonds on pyrrolidine-2,4-dione ring system, containing other reducible functions, has been investigated. Depending on the substrate the yield of the hydrogenation process can reach up to 95%. T...
Regioselective addition of aryl lithium to commercially available (S)-(+)-propylene oxide provides the corresponding (S)-aryl-2-propanol. The (R)-amphetamine is obtained by conversion of the alcohol to the tosylate followed by azide displacement and hydrogenation. Mitsunobu conversion of the alcohol to the (R)-bromide followed by azide displacement and hydrogenation affords the (S)-amphetamine....
Continuous flow systems for hydrogenation using polysilane-supported palladium/alumina (Pd/(PSi-Al(2)O(3))) hybrid catalysts were developed. Our original Pd/(PSi-Al(2)O(3)) catalysts were used successfully in these systems and the hydrogenation of unsaturated C-C bonds and a nitro group, deprotection of a carbobenzyloxy (Cbz) group, and a dehalogenation reaction proceeded smoothly. The catalyst...
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