A series of montmorillonite-based clays (KSF, KSF/0, K0, KP10, K10, KS from Sud-Chemie)
were obtained by treating a Bavarian bentonite with different acids and a Hungarian
bentonite (Mgd), and were used for the preparation of supported hydrated iron(III)
nitrates. The clay supports were characterized by different methods (chemical analysis,
nitrogen adsorption, X-ray powder diffraction, thermal analysis and solid-state NMR)
and the acidity of these solids was determined by infrared spectroscopy using pyridine
as a molecular probe. The supported iron nitrate reagents were investigated by thermal
and X-ray powder diffraction methods. The iron nitrate is present on the support as
an amorphous hydrate. The decomposition of the nitrate is shifted towards lower temperature
when it is supported and starts at 35-40 degrees C. The supported iron nitrate reagents
show high activities and selectivities in the oxidation of benzyl alcohol to benzaldehyde.
The high specific surface area and the Bronsted acidity of the support are determining
factors for the chemical activity of the supported system. The supported reagents
prepared according this procedure can be stocked for as long as six months without
any loss of chemical properties.