نتایج جستجو برای: catalytic reaction

تعداد نتایج: 474712  

Journal: :iranian journal of hydrogen & fuel cell 2014
hosna ghanbarlou soosan rowshanzamir mohammad javad parnian bagher kazeminasab

development of efficient electrocatalysts for oxygen reduction reaction (orr) is one of the most important issues for optimizing the performance of fuel cells and metal-air batteries. the introduction of nitrogen into carbon nanostructures has created new pathways for the development of non-precious electrocatalysts in fuel cells. in this work, nitrogen-doped graphene (ng) was synthesized by a ...

Journal: :Journal of the American Chemical Society 2003
Vitaliy I Timokhin Natia R Anastasi Shannon S Stahl

Dioxygen-coupled oxidative amination of olefins is an attractive, but challenging, catalytic transformation. The present work describes the first general method for intermolecular oxidative amination of aryl olefins with molecular oxygen as the stoichiometric oxidant. This palladium-catalyzed reactivity is compatible with several different nitrogen nucleophiles, including oxazolidinone, phthali...

1997
W. F. Schneider K. C. Hass R. Ramprasad J. B. Adams

First-principles quantum calculations are potentially of great value for assessing the plausibility of proposed catalytic reaction mechanisms. The present analysis of reaction pathways and energetics for key elementary steps in the catalytic decomposition of NO to N2 + O2 by Cu-exchanged zeolites yields novel insights into this widely studied reaction. We find evidence for a pathway involving t...

Steam reforming is one of the most important processes for producing hydrogen from hydrocarbon fuels such as LPG and has attracted much attention due to its high efficiency and economy. In this study, the LPG steam reforming reaction was investigated on nickel catalysts supported on four various zeolites (H-Y, Na-Y, HZSM5 and Ferrierite). The catalytic tests were performed in a tubular fixed be...

The chemistry of 2-oxo-1,2,3,4-tetrahydropyrimidines began to develop toward the end of 1893 year, when the first representatives of this class compounds were reported by P. Biginelli. Despite prior reports of several really effective catalytic and non-catalytic approaches towards Biginelli-type products, an overwhelming number of new catalysts for the Biginelli reaction have been recently publ...

H. Dashti Khavidaki M. R. Shishehbore R. Jokar

This study describes a new simple, sensitive and selective catalytic kinetic spectrophotometricmethod for the determination of vanadium (V). The method is based upon the catalytic effect ofvanadium (V) on the oxidation of Carminic acid by bromate in sulfuric acid media. The reaction wasfollowed spectrophotometrically by measuring the decrease in absorbance at 490 nm and thedependence of sensiti...

2016
Kapil Kandel Stacey Marie Althaus Takeshi Kobayashi Brian G. Trewyn Marek Pruski Igor I. Slowing Stacey M. Althaus Chorthip Peeraphatdit

The relative rates of the aldol reaction catalyzed by supported primary and secondary amines can be inverted by 2 orders of magnitude, depending on the use of hexane or water as a solvent. Our analyses suggest that this dramatic shift in the catalytic behavior of the supported amines does not involve differences in reaction mechanism, but is caused by activation of imine to enamine equilibria a...

Journal: :iranian journal of catalysis 0
farhad shirini department of chemistry, college of science, university of guilan, rasht, zip code 41335, iran. masoumeh makhsous department of chemistry, college of science, university of guilan, rasht, zip code 41335, iran. mohadeseh seddighi department of chemistry, college of science, university of guilan, rasht, zip code 41335, iran.

nanoporous sodium montmorillonite clay (na+-mmt) was used as a support for the immobilization of 1-methyl-3-(trimethoxysilylpropyl)-imidazolium hydrogen sulfate (na+-mmt-[pmim]hso4). this catalyst showed excellent catalytic activity for the preparation of 2-amino-3-cyano-5-oxo-5,6,7,8-tetrahydro-4h-benzopyrans via three-component reactions between aldehydes, dimedone and malononitrile. the proc...

Azita Farrokhi, Issa Yavari, Keivan Ghodrati

The four-component Hantzsch condensation reaction of dimedone, ethyl acetoacetate, ammonium acetate, and various aromatic and aliphatic aldehydes in the presence of catalytic amount of a magnetic nanoparticle-supported tribromide, as a green catalyst, under solvent‐free conditions at 80 °C affords functionalized 5-oxo-hexahydroquinolines in good to excellent yields. The magnetic Fe3O...

Nano-peanut shell‑OSO3H nanoparticles were simply prepared and characterized by the scanning electron microscopy (SEM), transmission electron microscope (TEM), fourier transform infrared (FT-IR), energy dispersive X-ray spectroscopy (EDX), and thermal analysis techniques (TGA/DTG). The catalytic activity of nano-peanut shell‑OSO3H was studied in the synthesis of biological...

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