نتایج جستجو برای: acid base catalyst

تعداد نتایج: 1012226  

Journal: Nanochemistry Research 2017

The new magnetic amine-functionalized graphene oxide (Fe3O4-GO-NH2) nanocatalyst was prepared through the reaction of 3-aminopropyltriethoxysilane (APTES) with magnetic graphene oxide (Fe3O4-GO). It was characterized by XRD, TEM, SEM, FT-IR and EDX techniques. The intrinsic carboxylic acids on the edges of Fe3O4-GO alo...

Journal: :Materials advances 2022

Three mononuclear Schiff-base–Ni( ii ) complexes act as electrocatalyst for hydrogen evolution reaction using acetic acid and trifluoroacetic the substrates. With increase in chain length of ligand, efficiency catalyst decreases.

The cross-coupling reaction between phenylboronic acid and various types of aryl halides (Suzuki reaction) was carried out using a catalytic amount of a new palladium catalyst (1-benzyl-3-(1-benzyl-1-methylpyrrolidin-1-ium-2-yl) pyridin-1-ium palladium chloride [DBNT][PdCl4]) in poly (ethylene glycol) (PEG-200) in the presence of KOH as the base. This new catalyst was synthesized and...

Journal: :Molecules 2010
Makoto Furutachi Zhihua Chen Shigeki Matsunaga Masakatsu Shibasaki

Catalytic asymmetric 1,4-addition of beta-keto esters to nitroalkenes is described. 2.5 mol % of a homobimetallic Lewis acid/Brønsted base bifunctional Co2-Schiff base complex smoothly promoted the reaction in excellent yield (up to 99%), diastereoselectivity, and enantioselectivity (up to >30:1 dr and 98% ee). Catalyst loading was successfully reduced to 0.1 mol %. Mechanistic studies suggeste...

2014
Yasuhiro Yamashita Yuki Saito Takaki Imaizumi Shū Kobayashi

While Lewis acids andmetal amides are among themost frequently usedmetal species, they are believed to be incompatible when combined. Here we describe a Lewis acid/metal amide hybrid, which contains electron-withdrawing groups and basic and bulky nitrogen functional groups in the same metal complex, as a novel catalyst. We have synthesized In(N(SiMe3)2)2Cl (In(HMDS)2Cl) and In(HMDS)2OTf as Lewi...

2014
Séverine Moret Paul J. Dyson Gábor Laurenczy

The chemical transformation of carbon dioxide into useful products becomes increasingly important as CO2 levels in the atmosphere continue to rise as a consequence of human activities. In this article we describe the direct hydrogenation of CO2 into formic acid using a homogeneous ruthenium catalyst, in aqueous solution and in dimethyl sulphoxide (DMSO), without any additives. In water, at 40 °...

Journal: :Journal of the American Chemical Society 2013
Vinit Choudhary Samir H Mushrif Christopher Ho Andrzej Anderko Vladimiros Nikolakis Nebojsa S Marinkovic Anatoly I Frenkel Stanley I Sandler Dionisios G Vlachos

5-(Hydroxymethyl)furfural (HMF) and levulinic acid production from glucose in a cascade of reactions using a Lewis acid (CrCl3) catalyst together with a Brønsted acid (HCl) catalyst in aqueous media is investigated. It is shown that CrCl3 is an active Lewis acid catalyst in glucose isomerization to fructose, and the combined Lewis and Brønsted acid catalysts perform the isomerization and dehydr...

Journal: :organic chemistry research 2015
elahe yazdani kobra azizi athar nakisa akbar heydari*

we have reported the fabrication of boric acid incorporated into surface of magnetite nanoparticles. the catalyst was characterized using spectroscopic, magnetic and thermal techniques (ft-ir, sem, xrd, icp, vsm and tga). it catalyzed mukaiyama aldol reaction of a ketene silyl acetal type nucleophile ((1-methoxy-2-methylprop-1-enyloxy) trimethylsilane), and various aldehydes (aromatic, aliphati...

Journal: :Molecules 2015
Elodie Brun Abdelmounaim Safer François Carreaux Khadidja Bourahla Jean-Martial L'helgoua'ch Jean-Pierre Bazureau Jose Manuel Villalgordo

We here disclosed a new protocol for the condensation of acetophenone derivatives and active methylene compounds with aldehydes in the presence of boric acid under microwave conditions. Implementation of the reaction is simple, healthy and environmentally friendly owing to the use of a non-toxic catalyst coupled to a solvent-free procedure. A large variety of known or novel compounds have thus ...

Journal: :Chemical communications 2011
Daniel J Coady Kazuki Fukushima Hans W Horn Julia E Rice James L Hedrick

Herein, we report the use of acid/base complexes for the ring opening polymerization of (L)-lactide. The salt formed from an equimolar reaction of benzoic acid and DBU produced a catalyst capable of controlled polymerizations allowing for targeted molecular weights and narrow polydispersities. The use of computational analysis suggests a bifunctional catalytic mechanism wherein both the monomer...

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