Synthesis, characterization and catalytic activity of AlSBA-3 mesoporous catalyst having variable silicon-to-aluminum ratios

AlSBA-3 mesoporous catalytic materials with different Si/Al ratios were synthesized; Al was incorporated in the mesoporous structure using the post-synthesis method. The catalysts were characterized using different techniques and methods, such as: XRD, BET, ICP, SEM microcopy, TEM microscopy and 27Al MAS NMR. Acidic properties were estimated by adsorption–desorption using pyridine as probe molecule followed by FTIR spectroscopy. FTIR studies showed the acidic properties with aluminum incorporation; lower Si/Al ratios increase the number of acid sites. Temperature-programmed desorption of pyridine showed that AlSBA-3 has a higher number of strong acid sites compared to other mesoporous materials such as Al-MCM-41, Al-SBA-15 and Al-SBA-16. It has been observed by 27Al MAS NMR spectroscopy, that the materials exhibit peaks with shifts of 50 ± 2 ppm and weak signal at 0 ± 2 ppm. The AlSBA-3 materials used as a catalyst showed high performance in the acid-catalyzed dehydration of isopropanol.

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► Efficient route for synthesizing new AlSBA-3 acid catalyst.
► High-framework Al content.
► Good structural integrity.
► Higher catalytic activity in dehydration of 2-propanol to propene.
► Great dispersion of Al species on the inner wall of the pores of SBA-3 with high Al contents.