MIXED ALUMINA CHROMIA PILLARED LAYERED ALPHA-ZIRCONIUM PHOSPHATE MATERIALS - ACIDITY AND CATALYTIC BEHAVIOR FOR ISOPROPYL-ALCOHOL DECOMPOSITION

The surface acidity and the catalytic behaviour of a series of mixed a lumina chromia pillared alpha-zirconium phosphates have been studied. The acid properties of these catalysts have been evaluated by measurem ents of the NH3 thermal programmed desorption, pyridine adsorption and dehydration of isopropyl alcohol at 220 degrees C. Both surface acidi ty and catalytic activity show a marked dependence on the Al/Cr ratio, but they are not a monotonic function of the catalyst composition. Th e most acid materials were those with Al/Cr ratios between 20/80 and 4 0/60. From this ratio, the acidity is gradually reduced with increasin g Al concentration. The activity of the mixed alumina chromia pillared materials for isopropyl alcohol decomposition is considerably enhance d with respect to the analogous chromia pillared compounds of the orde r of 20 times for maximum activity. The most active materials were tho se with the highest micropore volumes. All catalysts show selectivitie s higher than 99% for the dehydration of isopropyl alcohol.