Solid-state NMR studies of methanol-to-aromatics reaction over silver exchanged HZSM-5 zeolite

Solid-state NMR spectroscopy was used to study the conversion of methanol to aromatics (MTA) over silver exchanged HZSM-5 zeolites. It is the silver oxide rather than silver cation that plays a crucial role for the MTA reaction. The aromatic products (mainly toluene and benzene) are formed at the expense of the small alkanes (mainly propane and isobutane). AgZSM-5 zeolite calcined in air shows much higher activity and selectivity for the MTA conversion compared with AgZSM-5 zeolite calcined in vacuum or HZSM-5 zeolite. A possible reaction mechanism is proposed for the MTA conversion on the AgZSM-5 zeolite.