Please use this identifier to cite or link to this item: http://repositorio.unicamp.br/jspui/handle/REPOSIP/241819
Type: Artigo
Title: As-synthesized TEA-BEA zeolite: effect of Si/Al ratio on the knoevenagel condensation
Author: Chaves, Thiago F.
Pastore, Heloise O.
Hammer, Peter
Cardoso, Dilson
Abstract: The zeolite with BEA structure has been obtained using different Al amounts in the presence of tetraethylammonium as a structure directing agent. The effect of the Si/Al molar ratio on the crystal size, morphology, yield, chemical composition and catalytic properties was investigated. The materials have been characterized towards zeolitic properties by XRD, SEM, EDS, TGA, Si-29 MAS-NMR, XPS and TEM. The chemical composition of the crystals depends on the concentration of the initial reaction mixture and that a decrease in the Al content is associated with an increase in particle size. The characterization by TGA/DTA of as-synthesized zeolites with BEA structure showed that an increase of Si content resulted in the formation of [=Si-O-][TEA(+)] species, this was supported by Si-29 MAS-NMR. The XPS results also showed that the chemical composition of the surface differed from that of the bulk material, this was supported by TEM/EDS results. The results of catalytic activity tests indicated that a fraction of the [=Si-O-][TEA(+)]species was present on the external surfaces of the crystals, although the largest fraction appeared to be in the interior of the particles. As-synthesized BEA zeolite showed good catalytic activity and suggests that this material can be applied in other reactions involving basic sites. (C) 2014 Elsevier Inc. All rights reserved.
The zeolite with BEA structure has been obtained using different Al amounts in the presence of tetraethylammonium as a structure directing agent. The effect of the Si/Al molar ratio on the crystal size, morphology, yield, chemical composition and catalyti
Subject: Síntese hidrotermal
Catálise
Condensação de Knoevenagel
Country: Países Baixos
Editor: Elsevier
Citation: As-synthesized Tea-bea Zeolite: Effect Of Si/al Ratio On The Knoevenagel Condensation. Elsevier Science Bv, v. 202, p. 198-207 Jan-2015.
Rights: Fechado
Identifier DOI: 10.1016/j.micromeso.2014.09.058
Address: https://www.sciencedirect.com/science/article/pii/S1387181114005721
Date Issue: 2015
Appears in Collections:IQ - Artigos e Outros Documentos

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