Methanol conversion over ZSM-12, ZSM-22 and EU-1 zeolites: from DME to hydrocarbons production

Conversion of methanol to dimethyl ether (DME) and hydrocarbons was investigatedover zeolites with several 1-dimensional channel systems: ZSM-12, ZSM-22 and EU-1. The effect of reaction temperature, contact time and Time-On-Stream towards methanol conversion and products selectivity was investigated. It was found that ZSM-22 zeolite exhibits the best performances during conversion of methanol to DME (temperature range 180–240 °C) as consequence of the particular shape selectivity that inhibits coke formation and deactivation. On the contrary, when formation of hydrocarbons is desired (temperature up to 320 °C), ZSM-12 shows the highest activity in terms of light olefin yield with the highest C3/C2 ratio. The low selectivity towards C2 formation can be associated to the absence of both di- and tri-methyl benzenes formed during the reaction because when these species were detected, a higher ethylene productivity was observed lowering the C3/C2 ratio on the reactor out-stream.