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Preparation characterization, and acidity evaluation of perfluorosulfonic acid-functionalized silica catalysts / Gema Blanco-Brieva in Industrial & engineering chemistry research, Vol. 47 n°21 (Novembre 2008) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8005-8010 Titre : Preparation characterization, and acidity evaluation of perfluorosulfonic acid-functionalized silica catalysts Type de document : texte imprimé Auteurs : Gema Blanco-Brieva, Auteur ; Jose M. Campos Martin, Auteur Année de publication : 2008 Article en page(s) : p. 8005-8010 Note générale : Chemical engineering Langues : Anglais (eng) Mots-clés : Solid  acid  catalysts  perfluorsulfonic  acid  xps  technique Résumé : Three different hybrid organic/inorganic solid acid catalysts were prepared by grafting perfluorosulfonic acid onto amorphous silica gel by covalently anchoring β-sultone onto the hydroxyl groups on the silica surface. The anchored sulfonic groups have been characterized by thermal analysis, infrared spectroscopy, and photoelectron spectroscopy (XPS). Particularly, the XPS technique has proven to be an extremely powerful tool to determine the nature and chemical state of sulfur and carbon, as well as the surface density of the acid groups. The hybrid organic/inorganic systems functionalized with sulfonic acid groups were tested in the esterification reaction of acetic acid with methanol in liquid phase. Activity results obtained at 333 K and using an initial molar ratio AcOOH:MeOH = 1:1 revealed that the acid-functionalized, nonsilylated catalyst reaches acetic acid conversion of ∼50%, which contrasts with the much lower level (∼30%) reached by a commercial Nafion silica composite sample. Treatment of the catalysts in methanol at 333 K under stirring for 48 h emphasized that only the acid-functionalized and silylated sample retains some of the sulfonic groups. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800221f [article] Preparation characterization, and acidity evaluation of perfluorosulfonic acid-functionalized silica catalysts [texte imprimé] / Gema Blanco-Brieva, Auteur ; Jose M. Campos Martin, Auteur . - 2008 . - p. 8005-8010. Chemical engineering Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 47 n°21 (Novembre 2008) . - p. 8005-8010 Mots-clés : Solid  acid  catalysts  perfluorsulfonic  acid  xps  technique Résumé : Three different hybrid organic/inorganic solid acid catalysts were prepared by grafting perfluorosulfonic acid onto amorphous silica gel by covalently anchoring β-sultone onto the hydroxyl groups on the silica surface. The anchored sulfonic groups have been characterized by thermal analysis, infrared spectroscopy, and photoelectron spectroscopy (XPS). Particularly, the XPS technique has proven to be an extremely powerful tool to determine the nature and chemical state of sulfur and carbon, as well as the surface density of the acid groups. The hybrid organic/inorganic systems functionalized with sulfonic acid groups were tested in the esterification reaction of acetic acid with methanol in liquid phase. Activity results obtained at 333 K and using an initial molar ratio AcOOH:MeOH = 1:1 revealed that the acid-functionalized, nonsilylated catalyst reaches acetic acid conversion of ∼50%, which contrasts with the much lower level (∼30%) reached by a commercial Nafion silica composite sample. Treatment of the catalysts in methanol at 333 K under stirring for 48 h emphasized that only the acid-functionalized and silylated sample retains some of the sulfonic groups. En ligne : http://pubs.acs.org/doi/abs/10.1021/ie800221f