نتایج جستجو برای: catalyst

تعداد نتایج: 44027  

2010
P. Longo C. Costabile F. Grisi N. Latorraca P. Ciambelli M. Sarno C. Leone D. Sannino Don Melillo

The synthesis of polynorbornene by ring opening metathesis polymerizations (ROMP) in the presence of 2 nd generation Grubbs catalyst-functionalized nanotube initiators, is reported. A full characterization of Grubbs catalyst-functionalized nanotubes was performed by FTIR (Fourier Transform Infrared Spectroscopy) and TG-DTGMS (Thermogravimetrical Analysis coupled with Mass Spectrometer), in orde...

2014
Hiroshi Yoshida Ryohei Yamaoka Masahiko Arai

Hydrogen production through steam reforming of ethanol was investigated with conventional supported nickel catalysts and a Ni-containing smectite-derived catalyst. The former is initially active, but significant catalyst deactivation occurs during the reaction due to carbon deposition. Side reactions of the decomposition of CO and CH4 are the main reason for the catalyst deactivation, and these...

Journal: :Dalton transactions 2015
Catherine F Wise Dan Liu Kathryn J Mayer Patrick M Crossland Carolyn L Hartley William R McNamara

We report a nickel complex containing a conjugated bis-dithiocarbazate ligand that is an active catalyst for the reduction of protons into hydrogen gas. Light-driven hydrogen generation is observed from a system containing this molecular nickel catalyst coupled with a fluorescein photosensitizer and triethylamine sacrificial donor. The photocatalytic system is stable for over 70 hours, achievin...

Journal: :Chemical Society reviews 2010
Jagdeep Singh Carlo Lamberti Jeroen A van Bokhoven

Knowledge of the structure of catalysts is essential to understand their behavior, which further facilitates development of an active, selective, and stable catalyst. Determining the structure of a functioning catalyst is essential in this regard. The structure of a catalyst is prone to change during the catalytic process and needs to be determined in its working conditions. In this tutorial re...

Journal: :Journal of the American Chemical Society 2014
Desheng Kong Haotian Wang Zhiyi Lu Yi Cui

Development of a non-noble-metal hydrogen-producing catalyst is essential to the development of solar water-splitting devices. Improving both the activity and the stability of the catalyst remains a key challenge. In this Communication, we describe a two-step reaction for preparing three-dimensional electrodes composed of CoSe2 nanoparticles grown on carbon fiber paper. The electrode exhibits e...

Journal: :Organic & biomolecular chemistry 2010
Hyeong Bin Jang Ho Sik Rho Joong Suk Oh Eun Hye Nam Sang Eun Park Han Yong Bae Choong Eui Song

In this report, we demonstrate that self-aggregation is an intrinsic problem of bifunctional organocatalysts, especially in the case when the substrates do not have functional groups which are able to bind strongly with catalyst. Due to their self-association phenomena, the enantioselectivity of bifunctional catalysts dramatically decreases with increasing catalyst concentration or decreasing t...

Journal: :Journal of the American Chemical Society 2006
Sarah L Poe Muris Kobaslija D Tyler McQuade

We present a new microencapsulated catalyst and report its use in a tandem multicatalyst reaction. Using an encapsulation technique, we developed an active, site-isolated amine catalyst that is capable of catalyzing the addition of nitromethane to an aldehyde. When a second Lewis acid catalyst is added, the nitroalkene intermediate is trapped and converted to the corresponding Michael adduct. W...

Journal: :Chemical communications 2008
Ritu Ahuja Sabuj Kundu Alan S Goldman Maurice Brookhart Brian C Vicente Susannah L Scott

Tandem dehydrogenation-olefin-metathesis catalyst systems, comprising a pincer-ligated iridium-based alkane dehydrogenation catalyst and a molybdenum-based olefin-metathesis catalyst, are reported to effect the metathesis-cyclooligomerization of cyclooctane and cyclodecane to give cycloalkanes with various carbon numbers, predominantly multiples of the substrate carbon number, and polymers.

Journal: :Molecules 2015
Hongling Han Guodong Ding Tianbin Wu Dexin Yang Tao Jiang Buxing Han

A novel Cu and boron doped graphitic carbon nitride catalyst (Cu-CNB) was synthesized using cheap precursors and systematically characterized. The selective oxidation of toluene proceeded very smoothly over the catalyst at 70 °C using tert-butyl hydroperoxide (TBHP) as the oxidant to exclusively afford benzaldehyde. The catalyst can be used for at least five cycles without decrease in activity ...

Journal: :Chemical communications 2014
Hiroshi Shintaku Kiyotaka Nakajima Masaaki Kitano Michikazu Hara

A new heterogeneous catalyst, hydrophobic TiO4-deposited mesoporous silica, has been designed for the efficient Mukaiyama-aldol condensation, a water-participating Lewis acid-catalyzed reaction between a hydrophobic carbonyl compound and silyl enol ether. The prepared catalyst suspended in water exhibited high catalytic performance as a reusable catalyst for the reaction without a surfactant.

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