INVESTIGATION OF MONTMORILLONITE-BASED CLAYS IN THE PREPARATION OF SUPPORTED FERRIC NITRATE

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 suppor ts were characterized by different methods (chemical analysis, nitroge n adsorption, X-ray powder diffraction, thermal analysis and solid-sta te NMR) and the acidity of these solids was determined by infrared spe ctroscopy using pyridine as a molecular probe. The supported iron nitr ate reagents were investigated by thermal and X-ray powder diffraction methods. The iron nitrate is present on the support as an amorphous h ydrate. The decomposition of the nitrate is shifted towards lower temp erature when it is supported and starts at 35-40 degrees C. The suppor ted iron nitrate reagents show high activities and selectivities in th e oxidation of benzyl alcohol to benzaldehyde. The high specific surfa ce area and the Bronsted acidity of the support are determining factor s for the chemical activity of the supported system. The supported rea gents prepared according this procedure can be stocked for as long as six months without any loss of chemical properties.