Mesoporous Al-Fe-P-O solids prepared in non-aqueous medium: structure and surface acid catalytic behaviour.
(EN)
Aptel, G.
(EN)
Πανεπιστήμιο Ιωαννίνων. Σχολή Θετικών Επιστημών. Τμήμα Χημείας
(EL)
Aptel, G.
(EN)
Mesoporous aluminum-iron-phosphate solids of general formula Al100FeXPY with X=0, 5, 20 and Y=0, 15, 60 have been prepared in ethanolic medium in the presence of CTAB as precipitating precursor. The solids dried at 600 degrees C are acidic and predominately mesoporous, with specific surface areas (BET) between 310-460m(2).g(-1), pore volumes 0.20-0.35cc.g(-1), pare diameters 3-4 nm and surface acid density 8-18.10(17) sites.m(-2), depending on the sample composition. The addition of phosphorous favors the development of microporosity while the presence of iron results in more mesoporous solids. The surface acid catalytic behaviour of these materials was tested by isopropanol decomposition in a flow system. The products were propene and diisopropylether. The reaction rate for the total isopropanol conversion, as well as the selectivity towards diisopropylether (S-DIPE = 10-30%), increases with the density of surface acid sites, while that for propene drops with increasing acidity. A mechanism for the formation of the porous solids is proposed based on the increased interaction of iron with the phosphate species.
(EN)
