Ethanol to gasoline and sustainable aviation fuel precursors: an innovative cascade strategy over Zr-based multifunctional catalysts in the gas phase

In the biorefinery context, bioethanol upgrading has been identified as a valuable approach to develop a circular economy for fuels and chemicals production. In this work, the gas-phase, continuous flow catalytic upgrading of ethanol to blends with features close to those suitable for jet fuel is tackled through an innovative strategy based on the promotion of several reactions in cascade. Catalytic transfer hydrogenation, aldol condensation, dehydrogenative coupling, and ketonization reactions were combined in a one-pot approach over a relatively simple and cheap catalytic system consisting of copper nanoparticles supported on zirconium (and lanthanum) oxides. The resulting cascade reaction scheme led to the production of a blend of oxygenated adducts in the C6-C14 range with promising properties for use as jet fuel. By tailoring the features of the non-innocent support and/ or co-feeding hydrogen to the reactor, up to 40% selectivity for the jet fuel range fraction, with ethanol conversion above 85%, was achieved during the first 6 h of time on stream, simultaneously enhancing catalyst stability and lifetime.