Dimethylether production on zeolite catalysts activated by Cl^-, F^- and/or ultrasonication

The chlorinated and fluorinated zeolite catalysts were prepared by the impregnation of zeolites (H-ZSM-5, H-MOR or H-Y) using two halogen precursors (ammonium chloride and ammonium fluoride) in this study. The influence of ultrasonic irradiation was evaluated for optimizing both halogen precursors for production of dimethylether (DME) via methanol dehydration in a fixed bed reactor. The catalysts were characterized by SEM, XRD, BET and NH₃-TPD. The reaction conditions were temperatures from 100 to 300 ℃ and a WHSV =15.9 h^-1. All halogenated catalysts show higher catalytic activities at all reaction temperatures studied. However, the halogenated zeolite catalysts prepared under ultrasonic irradiation show higher performance for DME formation. The chlorinated zeolite catalysts show higher activity and selectivity for DME production than the respective fluorinated versions.