FT-IR Studies on Light Olefin Skeletal Isomerization Catalysis: III. Surface Acidity and Activity of Amorphous and Crystalline Catalysts Belonging to the SiO2–Al2O3System

摘要: Abstract The surface acidity of both amorphous and crystalline materials belonging to the SiO 2 –Al O 3 system (i.e., silicas, silica–aluminas with different Al contents, HZSM5 H-ferrierite (FER) zeolites, silicated pure γ-Al ) have been studied using FT-IR spectroscopy hydroxy groups adsorbed acetonitrile (AN) pyridine (Py). Lewis bonded H-bonded species AN observed, while a protonated form has characterized on HZSM5. A molecular sieve effect found for Py adsorption FER catalytic activity these in skeletal isomerization 1-butene isobutene also investigated. Bronsted scale correlates well conversion, measured after 20–40 min time stream. selectivity follows nearly an inverse trend, except FER, which shows higher than silica–alumina, quite good resistance coking, increasing Comparative analysis behavior catalysts spectrum their OH gives new light structure acidic OHs system. usefulness zeolite alumina-based n -butene is briefly discussed.