Publicación: The role of gold dopant in AP-Nb/MCF and AP-MCF on the Knoevenagel condensation of ethyl cyanoacetate with benzaldehyde and 2,4- dichlorobenzaldehyde
No hay miniatura disponible
Fecha
2019-03-15
Editor/a
Director/a
Tutor/a
Coordinador/a
Prologuista
Revisor/a
Ilustrador/a
Derechos de acceso
info:eu-repo/semantics/closedAccess
Título de la revista
ISSN de la revista
Título del volumen
Editor
Elsevier
Resumen
The Knoevenagel condensation with chlorine substituted benzaldehyde is difficult because of deactivation of aldehyde group. In this work we have shown that the activity of mesoporous cellular foams (MCF and Nb/MCF), modified with 3-aminopropyl-trimethoxysilane (AP) as a source of basicity, can be enhanced for this reaction by the anchoring of gold species. Gold species were loaded on amine modified materials towards Au/AP-MCF and Au/AP-Nb/MCF. Moreover, copper was used as a dopant for the latter sample giving rise to AuCu/AP/MCF. All these materials were characterized in details by different complementary techniques (N2 adsorption isotherms, TEM, UV–vis, TG/DTA, XPS, DFT calculations) which allowed the evaluation of states of all components of the catalysts. The interaction between niobium species and AP was evidenced to increase the stability of the basic modifier. This interaction was weakened by the introduction of gold and copper. The presence of both, negatively charged gold nanoparticles (NPs) and gold cations was crucial for the activation of 2,4-dichlorobenzaldehyde via the interaction with chlorine substituent atoms and aldehyde oxygen atoms as well as breaking of the “pseudo hydrogen bond” between aldehyde hydrogen atom and chlorine substituent, which destabilized the structure making it more active. Gold dopants did not influence significantly the condensation of ethyl cyanoacetate with benzaldehyde.
Descripción
Categorías UNESCO
Palabras clave
3-Aminopropyl-trimethoxysilane (AP)/MCF, Gold/copper dopants, Knoevenagel condensation, 2,4-Dichlorobenzaldehyde, Ethyl cyanoacetate
Citación
Centro
Facultad de Ciencias
Departamento
Química Inorgánica y Química Técnica