P. Braosgarcia et al., POROUS FLUORINATED ALUMINUM AND MIXED GALLIUM ALUMINUM OXIDE PILLAREDTIN PHOSPHATE MATERIALS WITH ACID PROPERTIES/, JOURNAL OF PHYSICAL CHEMISTRY B, 102(10), 1998, pp. 1672-1678
Fluorinated aluminum and mixed gallium/aluminum oligomers of high nucl
earity have been intercalated into cr-tin phosphate by refluxing fluor
inated Al and mixed Ga/Al oligomeric solutions in the presence of coll
oidal tin phosphate. P-31 and Al-27 MAS NMR spectroscopy has revealed
the existence of strong interactions between the phosphate layers and
the oligomeric guest species, conferring to these expanded materials a
high thermal stability, as confirmed by XRD studies. Formation of Al
and mixed Ga/Al oxide nanoparticle pillars in the interlayer region of
tin phosphate, upon calcination at 400 degrees C, gave rise to porous
materials with specific surface areas between 160 and 304 m(2) g(-1)
and micropore volumes close to 0.1 cm(3) g(-1). The pillared materials
are highly acidic solids and behave as dehydrating catalysts for the
decomposition reaction of isopropyl alcohol. The Lewis acid sites, bel
ieved to be mainly responsible for the catalytic activity, are associa
ted with low coordination sites of Al ions present in the interlayer o
xide pillars.