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Title: Characterization and acidic properties of AlMCM-41 prepared by conventional and post-synthesis alumination
Authors: Nascimento, Rubens Maribondo do
Costa, Maria José Fonseca
Chellappa, Thiago
Araujo, Antonio Souza de
Fonseca, Viviane Muniz
Fernandes Júnior, Valter José
Pacheco, Jose G. A.
Keywords: acidic properties of AlMCM-41;post-synthesis alumination;silicon;aluminium
Issue Date: 2015
Publisher: Australian Journal of Chemistry
Citation: COSTA, Maria José Fonseca; CHELLAPPA, Thiago; ARAÚJO, Antonio Souza de.; FONSECA, Viviane Muniz; FERNANDES JÚNIOR, Valter José; NASCIMENTO, Rubens Maribondo do; PACHECO, José G. A. Characterization and acidic properties of AlMCM-41 prepared by conventional and post-synthesis alumination. Australian Journal of Chemistry, [S.l.], v. 68, n. 1, p. 99, 2015. CSIRO Publishing. Disponível em: Acesso em: 07 abr. 2021.
Portuguese Abstract: The catalysts analysed in the current work are variations of MCM-41. The properties of these highly ordered mesoporous aluminosilicates were adjusted by an isomorphous substitution of Si by a trivalent cation, in this case Al3þ, generating catalysts of the AlMCM-41 type. The materials were synthesized with a silicon/aluminium ratio of 40, through two methods of impregnation of the metal: conventional and post-synthesis alumination. With the aim of determining the density of the acid sites of the Al40MCM-41 prepared by post-synthesis and conventional alumination, studies of the adsorption of n-butylamine probe molecule were carried out. Further, the studied material was characterized by thermogravimetry measurements, providing the profile of decomposition of the samples, which allowed calculation of the densities of the acid sites. The model-free kinetic algorithms were applied in order to determinate conversion and apparent activation energy. Comparison of energy-dispersive X-ray fluorescence and X-ray photoelectron spectroscopy measurements indicated that the post-synthesis method was more favourable based on the metal positioning, ‘anchored’ in the surface of the catalyst. The textural properties of the calcined Al40MCM-41 prepared by post-synthesis and conventional alumination were characterized by X-ray diffraction, N2 isothermal adsorption measurements (Brunauer– Emmett–Teller and Barrett–Joyner–Halenda), transmission electron microscopy, and X-ray photoelectron spectroscopy.
ISSN: Print: 0004-9425
Electronic: 1445-0038
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