Bio-fuel precursors prepared by ketonization of medium-chain fatty acids using efficient MnO ₂ nanorod catalysts

MnO2 nanorods were fabricated via a hydrothermal method and employed in ketonization of medium-chain fatty acids. Catalytic performance characterization indicates that MnO2 nanorods can efficiently catalyze the transformation of medium-chain fatty acids to the corresponding ketones. Specifically, full conversion of medium-chain fatty acids is attained, with ketone yield surpassing 97% at 300 °C under 0.1 MPa argon inert atmosphere. The catalytic activity is much higher than other reported metal oxides, such as TiO2, ZrO2, Fe2O3, and CeO2. The conversion was improved at higher temperature, but the yield of ketones decreased. In addition, longer carbon chain fatty acids require higher activation energy to conduct the reaction, leading to a low conversion. However, the selectivity of ketones was more than 90%, confirming that MnO2 is an excellent catalyst in ketonization. Finally, these ketones can be converted into hydrocarbons that meet the carbon number requirements for biofuels through hydrodeoxygenation treatment.