DME production via methanol dehydration with H form and desilicated ZSM-5 type zeolitic catalysts: Study on the correlation between acid sites and conversion

Methanol (MeOH) dehydration for Dimethyl ether (DME) production is one of the possible pathways to produce a green, synthetic fuel that can substitute fossil/conventional ones in automotive/transportation applications. DME synthesis in gas phase usually occurs in presence of an acid catalyst at moderate temperature (up to 250 °C). This work deals with the use of MFI-type zeolitic catalysts. H form and desilicated zeolite samples were synthesized, characterized, and tested to investigate their catalytic activity in MeOH dehydration reaction. Ammonia temperature-programmed desorption (NH3-TPD) and Fourier-transform Infrared spectroscopy (FT-IR) analyses were carried out to elucidate the amount and the nature of acid sites. Zeolite sample desilicated for 60 minutes presented a higher amount of Bronsted acid sites (that can be correlated to the superior catalytic activity), while the Turnover frequency (TOF) referred to the amount of Bronsted acid sites is very similar for the investigated samples. Finally, preliminary kinetic investigation via linear fitting of experimental data on the Arrhenius plot was carried out for simple first and second order kinetic models.