نتایج جستجو برای: hydrogenation mechanism

تعداد نتایج: 573485  

2017
Wei Liu Yingda Jiang Karl-Heinz Dostert Casey P O'Brien Wiebke Riedel Aditya Savara Swetlana Schauermann Alexandre Tkatchenko

The mechanistic understanding and control over transformations of multi-unsaturated hydrocarbons on transition metal surfaces remains one of the major challenges of hydrogenation catalysis. To reveal the microscopic origins of hydrogenation chemoselectivity, we performed a comprehensive theoretical investigation on the reactivity of two α,β-unsaturated carbonyls-isophorone and acrolein-on seven...

Journal: :Physical review letters 2005
A Nikitin H Ogasawara D Mann R Denecke Z Zhang H Dai K Cho A Nilsson

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...

Journal: :Journal of the Fuel Society of Japan 1980

Journal: :Dalton transactions 2015
Cheng Hou Jingxing Jiang Yinwu Li Zhihan Zhang Cunyuan Zhao Zhuofeng Ke

The mimic of hydrogenases has unleashed a myriad of bifunctional catalysts, which are widely used in the catalytic hydrogenation of polar multiple bonds. With respect to ancillary ligands, the bifunctional mechanism is generally considered to proceed via the metal-ligand cooperation transition state. Inspired by the interesting study conducted by Hanson et al. (Chem Commun., 2013, 49, 10151), w...

Journal: :Physical chemistry chemical physics : PCCP 2017
Qianling Lin Yinfeng Li Haimin Yao

In this paper, the in-plane torsional properties of two dimensional nanomaterials are revealed to be tunable by surface functionalization using molecular dynamics simulations. The torsional strengths of both graphene and graphyne under circular shearing are found to first decrease and then increase anomalously with the increase of the hydrogenation ratio. The minimum strength of such U-shaped s...

Journal: :The Journal of organic chemistry 2009
Da-Wei Wang Xiao-Bing Wang Duo-Sheng Wang Sheng-Mei Lu Yong-Gui Zhou Yu-Xue Li

The enantioselective hydrogenation of 2-benzylquinolines and 2-functionalized and 2,3-disubstituted quinolines was developed by using the [Ir(COD)Cl](2)/bisphosphine/I(2) system with up to 96% ee. Moreover, mechanistic studies revealed the hydrogenation mechanism of quinoline involves a 1,4-hydride addition, isomerization, and 1,2-hydride addition, and the catalytic active species may be a Ir(I...

Journal: :Dalton transactions 2009
Xuanhua Chen Wenli Jia Rongwei Guo Todd W Graham Meredith A Gullons Kamaluddin Abdur-Rashid

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 governing mechanism of surface reactions is a fundamental concern in heterogeneous catalysis. The Langmuir–Hinshelwood (LH) mechanism is widely accepted to control the surface reactions in many catalytic systems. This contribution derives and compares several important surface rate equations to evaluate their quality of fitting to the experimental data collected for a vapor-phase hydrogenat...

Journal: :Inorganics (Basel) 2023

The alloy TiFe is widely used as hydrogen storage material. However, the first hydrogenation difficult. It was found that addition of zirconium greatly improves kinetic hydrogenation, but mechanism not well understood. In this paper, we report use scanning photoemission microscopy to investigate composition and chemical state various phases present in how they change upon hydrogenation/dehydrog...

Journal: :Dalton transactions 2010
Claudine Rangheard César de Julián Fernández Pim-Huat Phua Johan Hoorn Laurent Lefort Johannes G de Vries

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...

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