Publicación: Metal-free synthesis of quinolines catalyzed by carbon aerogels: Influence of the porous texture and surface chemistry
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2017-04-17
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info:eu-repo/semantics/openAccess
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Elsevier
Resumen
We report herein an experimental and theoretical study of the Friedländer reaction, from 2-amino-5-chlorobenzaldehyde and ethyl acetoacetate, catalyzed by free-metal nanocatalysts based on carbon aerogels, to afford quinoline 3a. The developed methodology implies the combined use of carbon aerogels with solvent-free technologies under MW irradiation yielding the corresponding quinoline with moderated yield (66%) in only 5 min of reaction time. Our results demonstrated that the reactivity of the samples upon MW irradiation is strongly dependent on the porosity and surface chemistry of the carbon aerogels, the most active catalytic species being the most acidic oxygenated functional groups, –CO2H groups originated by oxidant treatment, or even in situ by hydrolysis of –CO–O–CO–, over the carbon surface.
The theoretical investigation of the reaction mechanism, by using computational methods, demonstrated that the synthesis of quinoline 3a in the absence or in the presence of carbon aerogels takes place by aldolization, subsequent heterocyclization and finally double dehydration. Relatively strong π-π stacking interactions between carbon support and reagents could be behind of the observed catalytic performance also extended for the oxygenated models. Furthermore, the concentration of –CO2H groups over the carbon surface is a key factor favoring each step of the reaction but acting as individual catalytic sites.
Descripción
Esta es la versión aceptada del artículo. La versión registrada fue publicada por primera vez en Chemical Engineering Journal, Volume 314, 2017, Pages 488-497, ISSN 1385-8947, está disponible en línea en el sitio web del editor: https://doi.org/10.1016/j.cej.2016.12.006
This is the accepted version of the article. The registered version was first published in Chemical Engineering Journal, Volume 314, 2017, Pages 488-497, ISSN 1385-8947, is available online at the publisher's website: https://doi.org/10.1016/j.cej.2016.12.006
Categorías UNESCO
Palabras clave
Porous catalytic system, carbon aerogel, surface chemistry, friedländer reaction, computational methods
Citación
Marina Godino-Ojer, Elena Soriano, Vanesa Calvino-Casilda, Francisco J. Maldonado-Hódar, Elena Pérez-Mayoral, Metal-free synthesis of quinolines catalyzed by carbon aerogels: Influence of the porous texture and surface chemistry, Chemical Engineering Journal, Volume 314, 2017, Pages 488-497, ISSN 1385-8947, https://doi.org/10.1016/j.cej.2016.12.006
Centro
Facultades y escuelas::Facultad de Ciencias
Departamento
Química Inorgánica y Química Técnica