Dual-templated synthesis of Si-rich [B]-ZSM-5 for high selective light olefins production from methanol

Methanol dehydration is a high potential route for the production of light olefins (C2-C4). In this study, hierarchical Si-rich [B]-ZSM-5 catalysts (Si/Al= 200) were prepared through one-pot hydrothermal synthesis, including boron as a promoter and ethanol as a low-cost secondary template. N2 adsorptiondesorption, XRD, FE-SEM, and FT-IR techniques were applied to characterize the catalysts. The effect of different amounts of ethanol and different operating conditions was studied on the ZSM-5 catalyst preparation and performance in methanol-to-olefins (MTO) reaction. The results showed that the optimum amount of ethanol (ethanol/TPABr=5) led to the highest crystallinity (91.2%), the highest specific surface area (>400 m2g-1), and total pore volume (0.19 cm3g-1). The best catalytic performance was obtained at temperature of 480°C and methanol hourly space velocity (WHSV) of 7.2 h-1. The optimum catalyst had the highest propylene selectivity (58%) and light olefin selectivity (85%). The results proved the high capability of the new strategy for the efficient and fast development of the MTO catalyst.