Synthesis and performance of novel liquid aviation fuels from biomass-derived β-pinene and various aldehydes

β-pinene represents a biomass-derived hydrocarbon characterized by its distinctive bicyclic structure. It is important to synthesize high-density fuels with excellent performance using β-pinene as the basic structural unit. In this study, a series of high-density fuels were synthesized through the oxidation of β-pinene, base-catalyzed (KOH, NaOH, etc.) aldol condensation, and catalytic hydrodeoxygenation using Pd/C and Hβ catalysts. The reaction conditions, including the catalyst type, reaction time, catalyst concentration and reaction temperature, were optimized for the aldol condensation reaction. Additionally, the reaction activities of nopinone with different aldehydes and the energy changes during the hydrodeoxygenation process were calculated to speculate on potential reaction paths and elucidate the reaction mechanism. The liquid hydrocarbon product obtained from hydrogenation and decompression distillation has a higher density (0.864–0.878 g/cm 3 ) and a net combustion heat of 45.42–46.67 MJ/kg than the petroleum-based aviation fuel RP-3, and a lower freezing point (−22.8∼-65.1 °C) and viscosity (9.09–47.01 mm 2 s −1 ,0 °C) than pinene dimer fuel. These favorable properties indicate that the synthesized hydrocarbon fuels have the potential to be used as a high-density fuel.