Catalytic performance of ferrierite and omega zeolites obtained through 2D-3D-3D transformation from Na-RUB-18 layered silicate

Synthetic zeolites have been consistently preferred for industrial and commercial purposes because of their uniform crystalline structure, highly pure composition and the possibility to modulate their intrinsic properties during the crystallization aiming at specific applications. This work explores an original hydrothermal route to obtain ferrierite zeolite using the layered silicate Na-RUB-18 as precursor. For that, the transformation was carried out in the presence of aluminum isopropoxide in various Si/Al molar ratios and using pyrrolidine or 1,3-diaminepropane as OSDA. The hydrothermal transformation from Na-RUB-18 led to pure ferrierite zeolite without other zeolitic crystalline phases. Also, omega zeolite was obtained through an interzeolitic conversion, in which the ferrierite was the parent structure. The samples were characterized by XRD, Al-27 and Si-29 MAS-NMR, SEM, XRF and NH3-TPD. In addition, the catalytic properties of the ferrierite and omega zeolites obtained were studied. The acid characteristics of these materials were evidenced by the high ethanol conversion presented and by the major dehydration to ethylene, a product catalyzed by Bronsted acid sites. Ferrierite synthesized using 1,3-diaminopropane as OSDA in particular showed promising catalytic performance, a result possibly related to the nanosized crystals obtained, in the shape of aggregated sheets.