نتایج جستجو برای: glycoluril based catalysts

تعداد نتایج: 2960450  

Journal: :Dalton transactions 2011
Ceri Hammond Jose A Lopez-Sanchez Mohd Hasbi Ab Rahim Nikolaos Dimitratos Robert L Jenkins Albert F Carley Qian He Christopher J Kiely David W Knight Graham J Hutchings

The reaction of glycerol with urea to form glycerol carbonate is mostly reported in the patent literature and to date there have been very few fundamental studies of the reaction mechanism. Furthermore, most previous studies have involved homogeneous catalysts whereas the identification of heterogeneous catalysts for this reaction would be highly beneficial. This is a very attractive reaction t...

Journal: :iranian journal of chemistry and chemical engineering (ijcce) 2009
ateeq rahman andreas martin kalevaru v. narayana benhard lucke

preparation of 2-chlorobenzonitrile, and benzonitrile are reported here from the corresponding 2-chlorobenzaldehyde and benzaldehyde by the reaction of ammonium hydroxide/vpo titania, vpo bulk (ammonium metavanadate) cucr catalyst/air system in methanol. all these catalysts showed better conversions with reasonable selectivity to aromatic. the results prove that bet surface area results show vp...

Journal: :Dalton transactions 2014
C C Gheorghiu B F Machado C Salinas-Martínez de Lecea M Gouygou M C Román-Martínez P Serp

Chiral rhodium hybrid nanocatalysts have been prepared by covalent anchorage of pyrrolidine-based diphosphine ligands onto functionalized CNTs. This work constitutes the first attempt at covalent anchoring of homogeneous chiral catalysts on CNTs. The catalysts, prepared with two different chiral phosphines, were characterized by ICP, XPS, N2 adsorption and TEM, and have been tested in the asymm...

Journal: :Journal of the American Chemical Society 2011
Shuangyin Wang Dingshan Yu Liming Dai

Having a strong electron-withdrawing ability, poly(diallyldimethylammonium chloride) (PDDA) was used to create net positive charge for carbon atoms in the nanotube carbon plane via intermolecular charge transfer. The resultant PDDA functionalized/adsorbed carbon nanotubes (CNTs), either in an aligned or nonaligned form, were demonstrated to act as metal-free catalysts for oxygen reduction react...

2016
Catherine Louis

This review focuses on the chemical methods used to prepare supported bimetallic heterogeneous catalysts, i.e., bimetallic nanoparticles deposited on a support. The review is limited to the preparation of gold-based bimetallic catalysts and moreover to bimetallic nanoparticles supported on powder inorganic supports, i.e., on the surface or in the porosity, and not on model supports such as sing...

Journal: :Journal of the American Chemical Society 2011
Koji Endo Robert H Grubbs

We report the development of ruthenium-based metathesis catalysts with chelating N-heterocyclic carbene (NHC) ligands that catalyze highly Z-selective olefin metathesis. A very simple and convenient procedure for the synthesis of such catalysts has been developed. Intramolecular C-H bond activation of the NHC ligand, promoted by anion ligand substitution, forms the appropriate chelate for stere...

Journal: :Chemical communications 2012
Peiyu Ge Micheál D Scanlon Pekka Peljo Xiaojun Bian Heron Vubrel Arlene O'Neill Jonathan N Coleman Marco Cantoni Xile Hu Kyösti Kontturi Baohong Liu Hubert H Girault

The activities of a series of MoS(2)-based hydrogen evolution catalysts were studied by biphasic reactions monitored by UV/Vis spectroscopy. Carbon supported MoS(2) catalysts performed best due to an abundance of catalytic edge sites and strong electronic coupling of catalyst to support.

Journal: :Chemical communications 2011
Carolin Lang Ute Gärtner Oliver Trapp

Here, we demonstrate a versatile screening platform for NHC ligand based catalysts by coating fused-silica micro capillaries with a bonded 1,3-bismesityl-2-imidazolidinylidene ligand. Such micro capillaries can be efficiently converted into (pre)-catalysts from various organometallic precursors by solid-phase chemistry techniques and can be quantitatively screened using on-column reaction chrom...

2009
E. M. Vass M. Hävecker S. Zafeiratos D. Teschner A. Knop-Gericke R. Schlögl

High pressure X-ray photoelectron spectroscopy (XPS) is used to characterize heterogeneous catalytic processes. The success of the new technique based on the possibility to correlate the catalytic activity and the electronic structure of an active surface. The dynamic character of a catalyst surface can be demonstrated impressively by this technique. In this contribution the basics of high pres...

2016
Víctor M. Blanco Zhengtao Chu Kathleen LaSance Brian D. Gray Koon Yan Pak Therese Rider Kenneth D. Greis Xiaoyang Qi

Multimodal tumor imaging with targeted nanoparticles potentially offers both enhanced specificity and sensitivity, leading to more precise cancer diagnosis and monitoring. We describe the synthesis and characterization of phenol-substituted, lipophilic orange and far-red fluorescent dyes and a simple radioiodination procedure to generate a dual (optical and nuclear) imaging probe. MALDI-ToF ana...

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