Alkyl bicyclo[2.2.2]octanes as high-energy-density bio-aviation fuel

This study focuses on developing a new class of high energy density (HED) bio-aviation fuel. Alkyl bicyclo[2.2.2]octanes (ABCOs) were designed as potential HED aviation fuel, and a C₁₂ ABCOs mixture was synthesized from renewable resources (α-phellandrene and maleic anhydride) using the Diels–Alder cycloaddition followed by hydrotreating. The synthesized ABCOs exhibited favorable fuel properties as HED fuel, including a gravimetric net heat of combustion comparable to Jet A-1 and higher density and volumetric net heat of combustion. ABCOs standalone showed poor low-temperature viscosities than Jet A-1 specifications but demonstrated no freezing behaviors even at extremely low temperatures. Fuel properties after blending ABCOs with Jet-A1 were also investigated, determining an upper limit of blending ratio of 44.1 vol%. These findings suggest that ABCOs can serve as a promising drop-in fuel for conventional jet fuel, while also potentially contributing to the formulation of bio-based and zero-aromatic high-performance jet fuels as a density-increasing component.