ELECTRON-PARAMAGNETIC-RESONANCE AND MOSSBAUER STUDIES OF FE3-MOO3 SYSTEM( IONS IN THE FE2O3)

The electron paramagnetic resonance (EPR) and Mossbauer spectra of iro n-molybdenum mixed oxides system have been investigated. Both EPR and Mossbauer measurements revealed the formation of ferric molybdate, Fe2 (MoO4)3 and the existence of two different Fe3+ species. The EPR spect ra of Fe2(MoO4)3, show two resonance lines of Fe3+ ions indicating tha t a strong exchange interaction is dominates in pure iron molybdate. M osbauer measurements revealed that the isomer shift (I.S) increases wi th increasing the iron content. A maximum of quadrupole splitting (Q.S ) is observed at the stoichiometric concentration corresponding to the formation of Fe2(MoO4)3. The effect of a catalytaic dehydration proce ss on the redox behaviour of Fe3+ located in iron molybdate frame work is investigated. Results indicate that the catalytaic dehydration of 2-proppanol over this catalyst reduces Fe3+ ions to Fe2+ leading to th e formation of the inactive phase FeMoO4. the essential role of oxygen , in the alcohol gas feed, in regeneration the activity of the catalys ts was demonstrated.