info:eu-repo/semantics/article
Assessment of surface acidity in mesoporous materials containing aluminum and titanium
Fecha
2009-04-01Registro en:
Araújo, Rinaldo dos Santos; Soares Maia, Debora Aline; Azevedo, Diana Cristina Silva de; Cavalcante Jr., Celio Loureiro; Rodríguez Castellón, Enrique; et al.; Assessment of surface acidity in mesoporous materials containing aluminum and titanium; Elsevier Science; Applied Surface Science; 255; 12; 1-4-2009; 6205-6209
0169-4332
CONICET Digital
CONICET
Autor
Araújo, Rinaldo dos Santos
Soares Maia, Debora Aline
Azevedo, Diana Cristina Silva de
Cavalcante Jr., Celio Loureiro
Rodríguez Castellón, Enrique
Jiménez López, Antonio
Resumen
The surface acidity of mesoporous molecular sieves of aluminum and titanium was evaluated using four different techniques: n-butylamine volumetry, cyclohexylamine thermodesorption, temperature-programmed desorption of ammonia and adsorption of pyridine. The nature, strength and concentration of the acid sites were determined and correlated to the results of a probe reaction of anthracene oxidation to 9,10-anthraquinone (in liquid phase). In general, the surface acidity was highly influenced by the nature, location and coordination of the metal species (Al and Ti) in the mesoporous samples. Moderate to strong Brönsted acid sites were identified for the Al-MCM-41 sample in a large temperature range. For mesoporous materials containing Ti, the acidity was represented by a combination of weak to moderate Brönsted and Lewis acid sites. The Ti-HMS sample exhibits a higher acidity of moderate strength together with a well-balanced concentration of Brönsted and Lewis acid sites, which enhanced both conversion and selectivity in the oxidation reaction of anthracene. © 2009 Elsevier B.V. All rights reserved.