SYNTHESIS, CHARACTERIZATION, AND CATALYTIC ACTIVITY OF GALLOSILICATE ANALOGS OF ZEOLITE ZSM-22

Crystalline gallosilicate zeolite, ZSM-22, has been synthesized and characterized. Gallium, incorporation in the lattice framework of the ZSM-22 structure was confirmed by chemical analysis, XRD, SEM, framework in spectroscopy, Ga-71 MAS n.m.r., d.t.a./d.t.g., sorption, ion-exchange, and catalytic techniques. The observed increase in the unit cell parameters and shifts in framework i.r. frequencies to lower wavenumbers indicate the presence of Ga3+ ions in the lattice framework of ZSM-22. The Ga-71 MAS n.m.r. study shows that Ga is in the tetrahedral position. The significant ion-exchange capacity (K/Ga = 0.90) and catalytic activity of GaZSM-22 in ethylbenzene conversion support the presence of gallium in the ZSM-22 structure. The catalytic activity is, however, lower than that of the Al analog.