Influence of Low and High Temperature Coking of H-GaMFI Propane Aromatization Catalyst on Its Surface and Catalytic Properties

H-Gallosilicate (MFI) (i.e., H-GaMFI) zeolite shows high activity/selectivity in the aromatization of lower alkanes, which is processes of treat practical importance. The high aromatization activity of this catalyst is attributed to its high dehydrogenation activity due to the presence of high dispersed nonframework Ga-oxide species (which are formed during hydrothermal synthesis and/or pretreatments to the zeolite) along with the zeolitic acid sites (or framework Ga), resulting in a bifunctional catalyst. However, this zeolite undergoes fast catalyst deactivation in the propane aromatization. The catalyst deactivation is attributed mainly to the coke formation on the zeolite. Earlier, a few studies have been reported on the deactivation of H-GaMFI zeolite in the propane aromatization. The catalyst deactivation is attributed mainly to the coke formation on the zeolite. Earlier, a few studies have been reported on the deactivation of H-GaMFI zeolite in the propane aromatization at 500-550{degrees}C for a short time-on-stream (10 h). It is interesting to know the effect of catalyst deactivation due to coking in the propane aromatization for much longer periods both at low (at 400{degrees}C) and high (at 550{degrees}C) temperatures on the product selectivity and also on the surface (viz., sorption capacity, acidity/acid strength distribution) and catalytic properties of the zeolite. The present investigation was undertaken for this purpose. 16 refs., 1 fig., 3 tabs.