Isomorphous substitution of ruthenium in MFI framework using the oxo-anions ruthenate(VI) and perruthenate(VII)

The oxo-anions: ruthenate(VI) and perruthenate(VII), as primary sources of ruthenium, have been investigated in the hydrothermal synthesis of zeolite ZSM-5. Crystalline material with ruthenium incorporated into lattice sites was isolated from starting gels containing up to 0.1 mole fraction Ru2O3/Si O2. There are no previous reports of the isomorphous replacement of alumini um by ruthenium in MFI-type-zeolites. X-Ray diffraction, infra-red spectros copy, chemical analysis, electron microscopy, and X-ray photoemission spect roscopy (XPS) all provide evidence for the presence of framework ruthenium. The development of new IR absorption bands in the asymmetric and symmetric Si=O=T stretching region, and the shift to lower wavenumbers is accompanie d by an increase in the interplanar spacings and unit-cell dimensions with increased Al replacement. A change in morphology is also observed.