Catalysis Letters, Vol.33, No.3-4, 401-412, 1995
Initial Activity Selectivity of H-Gallosilicate (MFI) in Propane Aromatization - Influence of H+ Exchange and Thermal Hydrothermal Pretreatments
Initial activity/selectivity of H-gallosilicate (MFI) zeolite with different degrees of H+ exchange and pretreated under different thermal and hydrothermal conditions in propane aromatization (at 500 degrees C) has been determined using a pulse microreactor connected to GC. It is found to be strongly influenced by the degree of H(+)exchange, calcination temperature and hydrothermal treatment at different temperatures and concentrations of steam. There exists a dose relationship between the acidity (measured in terms of pyridine chemisorbed at 400 degrees C) of the gallosilicate and its initial propane conversion and aromatization activity. Presence of strong acidic sites (attributed to FN Ga) at high concentration is essential for the well dispersed non-FW Ga oxide species to be active for dehydrogenation in the propane aromatization over the zeolite.