Ethanol Reactions over FeMoO Using Low O₂/Ethanol Molar Ratio: Reaction Network and Kinetics

The search for sustainable paths for the valorization of ethanol to produce other substances, such as acetaldehyde, is an object of study in heterogeneous catalysis. This research investigates the conversion of ethanol using an iron-molybdenum oxide catalyst with low O₂/EtOH molar ratios (0.0 and 0.05) in a Berty internal recycling reactor to clarify the dominant pathways and associated kinetics at an ethanol partial pressure above the flammability limit and to reveal the significant presence of dehydrogenation, dehydration reactions, and hydrogenation of ethylene to ethane. The catalyst characterization revealed the formation of the β-FeMoO4 phase, accompanied by an increase in specific area, pore volume, and pellet dimensions. The reaction network was also explored, and a kinetic model was developed and fit to experimental data, in order to estimate the kinetic parameters (kinetic constants and energies of activation) for the proposed reactions. Considering the low selectivity achieved for acetaldehyde with this catalyst under the studied conditions, it was concluded that it is not possible to apply an oxygen-distributed fed reactor. However, the experimental part, combined with the kinetic modeling, can contribute to further investigations on experimental conditions to enhance acetaldehyde production.