Since several decades, iron molybdate (Fe2(MoO4)3, noted as FMO) has been the industrial catalyst in oxidative dehydrogenation (ODH) of methanol to produce formaldehyde. In the industrial catalyst, FMO is typically prepared with an excess of molybdenum to enable good stability. The same kind of materials can be employed for ODH of ethanol with high selectivity and conversion to acetaldehyde, which is rarely studied yet. However, the exact role of Fe in the redox chemistry of the reactions is not clear. By in situ synchrotron based Mössbauer spectroscopy (SMS) we would like to probe how Fe is involved in the above-mentioned ODH reactions, using a capillary quartz tube oven reactor that has been used at SMS of ESRF previously. Moreover, we would like to perform pre-testings for coupling the in situ oven also with Raman spectrometry and quantitative product analysis. The aim is to enable structure-performance relationships, and gain a further understanding of the reaction mechanism.