The notable features of mesoporous aluminosilicates as catalytic supports for hydrodearomatization and hydrodesulfurization of fuels

Abstract

Despite being discovered more than 25 years ago, mesoporous aluminosilicates are still very relevant materials, considering the huge number of publications appearing every year harnessing them. Their notable features such as high BET surface area, accessible mesopore size, mild acidity and tunable pore wall thickness have resulted in different successful catalytic applications. Additionally, different kinds of mesoporous aluminosilicates may be found in literature (MCM-41, MCM-48, HMS, SBA-15, SBA-16, etc.) that allow to tailor to certain extent some physicochemical properties such as the spatial group, mesopore size and dimension, the pore wall thickness and consequently the hydrothermal stability, for the wanted catalytic application. This review is focused on discussing the main characteristics of the most common mesoporous aluminosilicates and exploring their reported performance in literature as supports of bifunctional catalysts for the hydrodearomatization (HDA) and desulfurization (HDS) of fuels. Although their hydrothermal stability has always been questioned by their lack of crystallinity, several successful applications of both MCM-41 and SBA-15 as supports of bifunctional catalysts for HDA/HDS of model compounds such as dibenzothiophene (DBT) can be found in literature, which in some cases interestingly also point out the prolonged stability of the catalyst, leading towards high yields of fuels by its mild acidity. Additionally, supported metal catalysts over mesoporous aluminosilicates might be the basis for the preparation of advanced bulk metal hydroprocessing catalysts, by application of different etching strategies. Therefore, this review will show these promising catalytic outcomes that opens up the application of mesoporous aluminosilicates as supports of bifunctional catalysts devoted to HDA/HDS of not only model sulfur/aromatic compounds but true fuels as well such as those proceeding from Kazakhstan oil.