Impact of Brønsted acid sites in MWW zeolites modified with cesium and amine species on Knoevenagel condensation

Wojtaszek-Gurdak, Anna, Calvino-Casilda, Vanesa, Grzesinska, Aneta, Martín-Aranda, Rosa María y Ziolek, Maria . (2019) Impact of Brønsted acid sites in MWW zeolites modified with cesium and amine species on Knoevenagel condensation. Microporous and Mesoporous Materials, Volume 280, 15 May 2019, Pages 288-296


Título Impact of Brønsted acid sites in MWW zeolites modified with cesium and amine species on Knoevenagel condensation
Autor(es) Wojtaszek-Gurdak, Anna
Calvino-Casilda, Vanesa
Grzesinska, Aneta
Martín-Aranda, Rosa María
Ziolek, Maria
Materia(s) Química
Abstract Layered zeolites of MWW family, MCM-22 and pillared MCM-36, were used as supports for base modifiers: cesium species (introduced via cation exchange or impregnation) and 3-aminopropyl trimethoxysilane (AP). The obtained materials were characterized by different methods (ICP-OES, N2 adsorption, XRD, XPS, TG/DTA, FTIR combined with pyridine adsorption, 2-propanol decomposition) for evaluation of chemical, structural and surface properties. All materials obtained were subjected to the Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate and ethyl acetoacetate. The effect of the zeolite structure, the stability of the catalysts as well as acid-base properties of zeolites on the activity in Knoevenagel condensation were considered. Of particular interest was the role of Brønsted acid sites (BAS). The nature of basic sites and BAS played different roles depending on the methylene compound used in the Knoevenagel condensation. AP-modified zeolites were the most active in the condensation between benzaldehyde and ethyl cyanoacetate, in which, in the first step of the reaction AP abstracted hydrogen from methylene carbon in ethyl cyanoacetate. A different reaction pathway was postulated for the condensation with ethyl acetoacetate on the basis of the highest activity of unmodified zeolites and the relationship between benzaldehyde conversion and the number of BAS. For this reaction protonation of benzaldehyde was postulated as the initial step of the reaction.
Palabras clave MWW zeolites
Modification with APTMS and Cs
Acidity
Basicity
Knoevenagel reactions
Editor(es) Elsevier
Fecha 2019-05-15
Formato application/pdf
Identificador bibliuned:DptoQIyQT-FCIE-Articulos-Rmmartin-0004
http://e-spacio.uned.es/fez/view/bibliuned:DptoQIyQT-FCIE-Articulos-Rmmartin-0004
DOI - identifier 10.1016/j.micromeso.2019.02.007
ISSN - identifier 1873-3093
Nombre de la revista Microporous and Mesoporous Materials
Número de Volumen 280
Página inicial 288
Página final 296
Publicado en la Revista Microporous and Mesoporous Materials, Volume 280, 15 May 2019, Pages 288-296
Idioma eng
Versión de la publicación publishedVersion
Tipo de recurso Article
Derechos de acceso y licencia http://creativecommons.org/licenses/by-nc-nd/4.0
info:eu-repo/semantics/closedAccess
Tipo de acceso Acceso cerrado
Notas adicionales The registered version of this article, first published in Microporous and Mesoporous Materials, is available online at the publisher's website: Elsevier, https://doi.org/10.1016/j.micromeso.2019.02.007

 
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Creado: Thu, 25 Jan 2024, 20:54:16 CET