نتایج جستجو برای: acidic catalyst

تعداد نتایج: 77393  

2011
MUHAMMAD RAZA SHAH QAMAR ALI ZAHID HUSSAIN ITRAT ANIS

Selective acylation of alcohol has enjoyed great attraction of chemists due to its significance in synthetic organic chemistry especially in protecting group chemistry as reflected by the number of methods that have been developed to effect this transformation. To meet the challenging task of chemoselective transformation of aliphatic alcohols in the presence of phenolic alcohol mainly acidic c...

A facile and efficient protocol for the synthesis of 1,8-dioxo-octahydroxanthenes has been developed by one-pot Knoevenagel condensation, Michael addition and cyclodehydration reaction of dimedone (active methylene carbonyl compound) with aromatic aldehydes in the presence of Iron (III) sulfate hydrate as a solid acidic catalyst under solvent-free conditions. Various aromatic aldehydes were uti...

This article describe the applicability of 1,4-disulfopiperazine-1,4-diium chloride ([Piper-(SO3H)2].2Cl) as a green, versatile and Brönsted acidic ionic catalyst in the promotion of the synthesis of phthalazine derivatives via one-pot three component reaction between aromatic aldehydes, 1,3-diketone derivatives and phthalhydrazide under solvent-free reaction cond...

E. Rezaee Nezhad S. Karimian S. Sajjadifar

The Magnetically recoverable Fe3O4 nanoparticle and the supported brønsted acidic ionic liquid 1-methyl-3-(3-trimethoxysilylpropyl) imidazolium hydrogen sulfate (Fe3O4-IL-HSO4) were synthesized and used as efficient magnetic catalysts for the regioselective thiocyanation of aromatic and heteroaromatic compounds at room temperature in Water: Ethanol. This procedure provided the target thiocyanat...

2016
Wei Gao Dana Havas Shiva Gupta Qin Pan Nanfei He Hanguang Zhang Hsing-Lin Wang Gang Wu

Reduced graphene oxide (rGO), as a newly emerged carbon material, has attracted great attention concerning its applications for electrocatalysts. Presently, there are mixed opinions regarding the advantages to using rGO as a support for preparing nonprecious metal catalysts for the oxygen reduction reaction (ORR). The primary goal of this work is to determine whether rGO would be favorable for ...

Journal: :Chemical communications 2012
Mshari A Alotaibi Elena F Kozhevnikova Ivan V Kozhevnikov

Acidic heteropoly salt Cs(2.5)H(0.5)PW(12)O(40) doped with Pt nanoparticles is a highly active and selective catalyst for one-step hydrogenation of methyl isobutyl and diisobutyl ketones to the corresponding alkanes in the gas phase at 100 °C with 97-99% yield via metal-acid bifunctional catalysis.

Journal: :Chemical communications 2009
Mårten Ahlquist Roy A Periana William A Goddard

Quantum mechanical (QM) results are used to establish the role of sulfuric acid solvent in facilitating the reaction between Pt(II)(bpym)Cl(2) (bpym = 2,2'-bipyrimidinyl) and methane; coordination of methane to the platinum catalyst is found to be catalyzed by the acidic medium.

Journal: :Chemical communications 2010
Xiaoguang Bao Dieter von Deak Elizabeth J Biddinger Umit S Ozkan Christopher M Hadad

Oxygen reduction reaction (ORR) over a carbonaceous catalyst (1) with a phosphinate (>P(=O)OH) moiety was explored computationally. Under the acidic environment of a fuel cell, 1 could be active for ORR and be converted to 2 with a >P(OH)(2) moiety. An edge phosphinate could be active for both 2- and 4-electron ORR.

2006
Darren A. Walsh José L. Fernández Allen J. Bard

Additional bimetallic electrocatalysts for the oxygen reduction reaction ORR in acidic media were designed using a previously reported thermodynamic selection guide. The electrocatalyst mixtures were prepared in large arrays on glassy carbon substrates and the electrocatalytic activity was screened using scanning electrochemical microscopy SECM . Activities were measured for a range of bimetall...

2015
M. Dietrich D. Rauch U. Simon A. Porch R. Moos

To meet today’s emission standards, the ammonia-based selective catalytic reduction (SCR) has become the major NOx control strategy for light and heavy diesel engines. Before NOx reduction can proceed, adsorption of ammonia on the acidic sites of the catalyst is necessary. For improvements in efficiency and control of the exhaust gas aftertreatment, a better understanding of the ammonia storage...

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