نتایج جستجو برای: Hydrogenolysis

تعداد نتایج: 731  

Journal: :Angewandte Chemie 2013
Chang-Bin Yu Yong-Gui Zhou

Hydrogenolysis is an important synthetic method in organic chemistry, and has been widely applied in industrial processes, natural product synthesis, and the removal of waste materials. In practice, most hydrogenolysis reactions have been used for the synthesis of racemic or achiral compounds. Very few studies on asymmetric homogeneous hydrogenolysis have been reported. The first example, repor...

Journal: :Science 2011
Alexey G Sergeev John F Hartwig

Selective hydrogenolysis of the aromatic carbon-oxygen (C-O) bonds in aryl ethers is an unsolved synthetic problem important for the generation of fuels and chemical feedstocks from biomass and for the liquefaction of coal. Currently, the hydrogenolysis of aromatic C-O bonds requires heterogeneous catalysts that operate at high temperature and pressure and lead to a mixture of products from com...

Journal: :Journal of the American Chemical Society 2015
Elif I Gürbüz David D Hibbitts Enrique Iglesia

This study combines theory and experiment to determine the kinetically relevant steps and site requirements for deoxygenation of alkanols and alkanals. These reactants deoxygenate predominantly via decarbonylation (C-C cleavage) instead of C-O hydrogenolysis on Ir, Pt, and Ru, leading to strong inhibition effects by chemisorbed CO (CO*). C-C cleavage occurs via unsaturated species formed in seq...

2012
Tanuja Srivastava

Sucrose hydrogenolysis is industrially important for the production of polyols. To provide high glycerol yield under milder reaction conditions, a nickel catalyst promoted by Molybdenum and copper supported on kieselguhr was synthesized and optimized using Response Surface Methodology. A 3X5 experimental design has been adopted to study the effect of these constituents. A linear second-order mo...

Journal: :Chemical communications 2012
Akifumi Noujima Takato Mitsudome Tomoo Mizugaki Koichiro Jitsukawa Kiyotomi Kaneda

Gold nanoparticles on hydrotalcite act as a heterogeneous catalyst for the chemoselective hydrogenolysis of various allylic carbonates to the corresponding terminal alkenes using H(2) as a clean reductant. The combination of gold nanoparticles and basic supports elicited significantly unique and selective catalysis in the hydrogenolysis.

Journal: :ChemSusChem 2009
Gerald S Macala Theodore D Matson Charles L Johnson Robert S Lewis Alexei V Iretskii Peter C Ford

A (super)critical transfer: The consecutive hydrogenolysis and hydrogenation of the lignin model compound dihydrobenzofuran was studied in supercritical methanolic solutions using porous metal oxide catalysts. These catalysts promote H(2) production from methanol followed by hydrogenolysis of the ether linkages and reduction of the aromatic rings, leading principally to a mixture of cyclohexanols.

2014
David W. Flaherty David D. Hibbitts Elif I. Gürbüz Enrique Iglesia

Ethane hydrogenolysis involves C–C bond rupture in unsaturated species in quasi-equilibrium with gaseous reactants and H 2 on metal clusters, because C–C bonds weaken as C-atoms replace hydrogen with exposed metal atoms from catalyst surfaces. The nature and reactivity of such adsorbed species are probed here using kinetic data and density functional theory (DFT) for the case of Ir surfaces, bu...

2004

Fluorescence yield near-edge spectroscopy (FYNES) above the carbon K edge and temperature programmed reaction spectroscopy (TPRS) have been used as the methods for characterizing the reactivity and structure of adsorbed aniline and aniline derived species on the Ni(100) and Ni(111) surfaces over an extended range of temperatures and hydrogen pressures. The Ni(100) surface shows appreciably high...

2012
Zhen Yan Yunxi Yao D. Wayne Goodman

Hydrogenolysis and dehydrogenation of propane were studied over model nickel–gold catalysts. The supported model Ni–Au catalysts were prepared by depositing Ni and Au onto a planar silica film. Infrared reflection absorption spectroscopic data showed that isolated Ni sites appeared and became dominant on the surface with the addition of Au to Ni. For the conversion of propane in the presence of...

2002
D. W. Goodman

Single crystal catalysts have been used to investigate ethane hydrogenolysis. The apparatus used in these studies allows for catalyst preparation and surface characterization in ultrahigh vacuum (UHV) with an in vacua transfer to a second UHV chamber designed for high pressure kinetic studies. Kinetic measurements on single crystals of nickel show the hydrogenolysis of ethane to be “structure s...

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