Methanol dehydration into dimethylether over ZSM-5 type zeolites: Raise in the operational temperature range

Zeolites having different pore topologies were tested in the dehydration of methanol into dimethylether (DME) under inert and oxidative atmosphere. The experiments were carried out under air to inhibit the Methanol-To-Hydrocarbons (MTH) reaction, which tends to decrease the selectivity in DME. In addition, the presence of air led to broadening the operational temperature range (OTR) up to 400 °C, while maintaining the DME selectivity above 90% during 50 h on stream. Among the solid acid catalysts, the ZSM-5 zeolites exhibited the higher catalytic activity, with a degree of methanol conversion close to 75%. Furthermore, H-[F]ZSM-5 zeolite, prepared via a fluoride-mediated route, remains the more stable and selective toward DME at 400 °C.

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► Efficient methanol conversion (73%) into dimethylether was achieved (selectivity >99%).
► The operational temperature range of the reaction was enhanced up to 400 °C under air flow.
► Synthesis of ZSM-5 in fluoride medium led to maintain a selectivity in DME > 90% at 400 °C.
► Long-term experiments were performed under air and no loss in activity was observed at 400 °C.