Propane Transformation on In-Modified Zeolite BEA

In-modified zeolites possess promising catalytic properties for light alkane dehydrogenation and aromatization. However, the role of different indium species, which are present in zeolite pores after activation, remains unknown. Here, the transformation of propane on BEA zeolite containing either In+ or InO+ species in zeolite pores has been monitored with 13C MAS NMR at 298–773 K. It is inferred that In+/H-BEA zeolite with In+ sites is inactive for alkane conversion at T < 723 K. The transformation of the alkane on InO+/H-BEA zeolite occurs by two parallel routes: dehydrogenation of propane followed by the formed alkene aromatization to simple aromatic hydrocarbons and the alkane oxidation resulting in C2–C3 carboxylic acids. Propane activation by either C–H or C–C bond cleavage on InO+ sites and pathways of carboxylic acid formation from the products of the alkane dissociative adsorption are discussed.