Insight into the production of aviation fuel by aldol condensation of biomass-derived aldehydes and ketones followed by hydrogenation

The catalytic conversion of renewable biomass-derived aldehydes and ketones to aviation fuels is very attractive for sustainable development. We provided insight into the production of aviation fuel from typical biomass carbonyl platform compounds (furfural, acetone, butanone, and butyraldehyde) by aldol condensation followed with hydrodeoxygenation over bifunctional catalyst Ni/Mg–Al-O/AC, focusing on the mechanism of condensation reaction. It was found that high temperature is not only conducive to aggravate the depth of aldehyde ketone condensation reaction, further convert dimer to trimer, but also promote its self-condensation. The optimal condensation temperature of aldehydes and ketones under this idea was 170 °C, the carbon number range of the jet fuel intermediates was C7–C14, and the yield of condensates reached 79.23%. In order to explore the mechanism in the aldol condensation of aldehydes and ketones, the evolution law of typical products was studied by controlling the reaction time, and seven main condensation pathways were proposed. The ratios of aldehyde/ketone in the reactant and the ratios of each component within the aldehyde and ketone were adjusted, and it was found that the reaction priority of chain aldehydes is the highest in this reaction system, and the reaction priority of small-molecule ketones with low carbon number is higher than that of high carbon number ketones. The presence of long-chain groups in the hydrogenated oil increased the density of jet fuel, and it has a higher calorific value, which are very promising as aviation fuels or additives of aviation bio-fuels.