Aqueous and Biphasic Coupling of Furfural and Cyclopentanone for the Synthesis of Bio-Jet Fuel Precursors

We report on the aldol condensation of furfural and cyclopentanone in aqueous and biphasic mediums as a promising step for producing sustainable aviation fuel. Key parameters, including catalyst concentration, reactant concentration, temperature, and solvent, were found to significantly influence conversion and product selectivity. Alkaline conditions were essential for aldol coupling, with significant conversion observed at pH 12 and higher. The activation energies for the formation of the dimeric and trimeric aldol adducts were similar at 74 and 76 kJ/mol, respectively. Biphasic conditions were employed to prevent product precipitation, leading to reactor and equipment fouling. For biphasic conditions, the extraction of the reactants and dimeric intermediates to the organic phase affected rate and selectivity, resulting in the dilemma. Good product extraction leads to inevitable reactant extraction. Based on these findings, an integrated biphasic process design was proposed, utilizing process-owned solvents to optimize the separation and recycling of aqueous streams and improve the overall process efficiency.