Effect of NaNO2, HNO3 and H2SO4 on the structure and reactivity of gamma-alumina

The influence of NaNO2, HNO3 and H2SO4 on the structure and morphology of gamma-alumina was investigated by XRD, BET, SEM and FT-IR spectroscopy. Selected amounts of NaNO2, HNO3 and H2SO4 were added to a solution of aluminum isopropoxide (as a precursor for the boehmite synthesis). The boehmite samples were calcined at 350 and 600 ℃ to form the semi-crystalline high surface area gamma-Al2O3. The reactivity and selectivity of the modified gamma-alumina catalysts were examined using dehydration reaction of 2-octanol. There was a good correlation between reactivity, selectivity and the amounts (and type) of the modification. The dominant product was cis-2-octene for all of the catalysts. Low conversion and high selectivity were obtained for dehydration of 2-octanol over alumina modified with NaNO2. High conversion, low selectivity and excessive isomerization were found for gamma-alumina catalyst modified with H2SO4.