Isomorphous substitution in ZSM-22 zeolite. The role of zeolite acidity and crystal size during the skeletal isomerization of n-butene

Synthesis and Characterization of Al-TON Zeolite Using a Dialkylimizadolium as Structure-Directing Agent

“…This morphology was already observed for TON zeolites. 28 MFI zeolites present interesting morphology of regular and uniform microspheres with diameters ranging between 10 and 15 μm (Figure 10b). The same morphology for ZSM-5 was obtained by Mignoni et al 14 , which reports the synthesis of ZSM-5 in form of microspheres constituted by hexagonal prisms, with diameter of 35 μm.…”

Catalysis in the Upgrading of Fischer–Tropsch Syncrude

“…260,261 The skeletal IS of n-butene (in N 2 at 350 1C) was conducted over a series of M-ZSM-22 (M ¼ Al, Ga and Fe) catalysts with the different Si:M ratios and particle sizes. 262 For catalysts having similar composition and particle size, the activity increased with increasing acidity, Al 4 Ga 4 Fe, whereas the opposite trend was observed for the isobutene selectivity. For Ga-and Fe-ZSM-22, better than 80% selectivity to isobutene at 50% butene conversion was achieved.…”

The Chemistry of Catalytic Processes

“…Among the medium pore zeolites, better results were obtained for those having a monodirectional channel structure, such as ZSM-22, Theta-1, and ZSM-23. The selectivity to isobutene has been shown to improve by decreasing the density of Bronsted acid sites (increasing Si/Al ratio) (19,20,21,22) and by decreasing their acid strength by replacing framework Al 3+ by other trivalent cations, such as Ga 3+ andFe 3+ (23,24,25,26).…”