Hydrothermal synthesis of ferrisilicates with ZSM-48 structure from precipitated gels

A ferrisilicate with ZSM-48 structure (designated as Fe-ZSM-48) has been sy nthesized from amorphous ferrisilicate gel prepared by use of sodium silica te and iron chloride. X-ray diffraction, Fourier transform infrared and ele ctron spin resonance measurements indicate that Fe3+ ions are incorporated into this framework. The characterization of samples by scanning electron m icroscopy and thermal analysis techniques show that the crystallite morphol ogy and thermal properties of the as-synthesized Fe-ZSM-48 differ from thos e of the pure-silica ZSM-48. Furthermore, the effects of the SiO2/Fe2O2 rat io, 1,6-hexanediamine and water contents in the reaction mixture on the pro ducts are also investigated. (C) 1998 Elsevier Science B.V. All rights rese rved.