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Updated: Oct 7, 2025

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
Published on: October 18, 2019
Promoting Aromatic C-H Activation through Reactive Brønsted Acid-Base Pairs on Penta-Coordinated Al-Enriched
Zichun Wang1, Yijiao Jiang2, Alfons Baiker3
1Laboratory for Catalysis Engineering, School of Chemical and Biomolecular Engineering, The University of Sydney, Sydney, New South Wales 2006, Australia.
Abstract:
The surface acidity and local coordination environment of zeolites and amorphous silica-aluminas (ASAs) can promote acid-catalyzed C-H activation in many important hydrocarbon conversion reactions. Acid sites generated by penta-coordinated Al species (AlV) can lead to enhanced acidity and changes in the surface coordination. We evaluated the potential of flame-derived ASAs with enriched AlV for C-H activation using hydrogen/deuterium (H/D) exchange with benzene-d6. With increasing Al content of ASAs, the exchange rate increased, whereas the activation energy (Ea) slightly decreased due to the enhanced Brønsted acidity. The ASAs exhibited significantly higher exchange rates and lower Ea values than the sol-gel-derived ASAs and zeolite H-ZSM-5. The superior activity is attributed to the fact that more oxygen coordinated with AlV species on flame-made ASAs, which can act as acceptors for D+, enhancing the deuterium displacement. These findings could offer a valuable alternative strategy for tailoring high-performance solid acids to promote hydrocarbon conversion reactions.
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