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

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dc.contributor.authorWojtaszek Gurdak, Anna
dc.contributor.authorGrzesinska, Aneta
dc.contributor.authorZiolek, María
dc.contributor.authorCalvino Casilda, Vanesa
dc.contributor.authorMartín Aranda, Rosa María
dc.date.accessioned2024-05-20T11:58:09Z
dc.date.available2024-05-20T11:58:09Z
dc.date.issued2019-05-15
dc.description.abstractLayered 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.en
dc.description.versionversión publicada
dc.identifier.doihttp://doi.org/10.1016/j.micromeso.2019.02.007
dc.identifier.issn1873-3093
dc.identifier.urihttps://hdl.handle.net/20.500.14468/12769
dc.journal.titleMicroporous and Mesoporous Materials
dc.journal.volume280
dc.language.isoen
dc.publisherElsevier
dc.relation.centerFacultad de Ciencias
dc.relation.departmentQuímica Inorgánica y Química Técnica
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/4.0
dc.subject.keywordsMWW zeolites
dc.subject.keywordsModification with APTMS and Cs
dc.subject.keywordsAcidity
dc.subject.keywordsBasicity
dc.subject.keywordsKnoevenagel reactions
dc.titleImpact of Brønsted acid sites in MWW zeolites modified with cesium and amine species on Knoevenagel condensationes
dc.typejournal articleen
dc.typeartículoes
dspace.entity.typePublication
relation.isAuthorOfPublication2c001973-924e-4c7c-a0b0-246e6b9a778e
relation.isAuthorOfPublicationbafbca28-7ba9-4a29-b350-ebdcbc2381bb
relation.isAuthorOfPublication.latestForDiscovery2c001973-924e-4c7c-a0b0-246e6b9a778e
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