Oxidation of Acetaldehyde and Propionaldehyde on a VOx/TiO2 Catalyst in the Presence of Water Vapor

The partial oxidation of acetaldehyde and propionaldehyde on a TiO2 supported VOx catalyst in the presence of water vapor was investigated at temperatures from 120 to 280 °C. Depending on the kind of aldehyde and reaction temperature, the selective oxidation to the appropriate carboxylic acid and an oxidative splitting to lower carboxylic acids took place. Acetaldehyde was oxidized to acetic acid with selectivities up to 82 % at ∼ 200 °C whereas propionic acid was formed only with selectivities of about 20 % at ∼ 140 °C in the oxidation of propionaldehyde. The oxidative cleavage of propionaldehyde led to the formation of more acetic acid than formic acid, which was in agreement with the higher formation of COx compared to that in the acetaldehyde oxidation. The presence of water and the increasing concentration of oxygen in the feed was found to enhance the selectivity towards the formation of C1 to C3 carboxylic acids by inhibiting the total oxidation of aldehydes and carboxylic acids. The partial oxidation of acetaldehyde and propionaldehyde on a TiO2 supported VOx catalyst was investigated in the presence of water at different reaction temperatures with the objective of contributing to a better understanding of the mechanism of n‐butane/n‐butene oxidation to acetic acid, the oxidative dehydrogenation of C2, C3 hydrocarbons, and the selective oxidation of ethanol.