Synthesis of high density and low freezing point jet fuels range cycloalkanes with cyclopentanone and lignin-derived vanillins

In this work, a “cyclopentanone-vanillin” strategy was proposed for the preparation of jet fuel range cycloalkanes from lignocellulose-derived ketones and lignin-derived aldehydes via aldol condensation and hydrodeoxygenation (HDO). Ethanolamine lactate ionic liquid (LAIL) exhibited excellent catalytic activity in the aldol condensation of cyclopentanone and vanillin. Desired mono-condensation and bi-condensation products were obtained with yield of 95.2% at 100 °C. It is found that the synergy effects between amino group of ethanolamine and hydroxyl group of lactic acid play a key role in the aldol condensation. The condensation products were converted into cycloalkanes by HDO over 5%Pd/Nb2O5 catalyst. The density of the obtained HDO products is 0.89 g/cm3 and the freezing point is lower than −60 °C. These results suggest that the resulted cycloalkanes can be used as additives to improve the density and low-temperature fluidity of the jet fuels.