Catalytic production of fused tetracyclic high-energy-density fuel with biomass-derived cyclopentanone and benzoquinone

Abstract

High-energy-density (HED) fuels (e.g. JP-10) are of great importance in safeguarding territorial air security, since they can increase the flight range and payload of military aircrafts. To reduce the reliance on limited petroleum source, the production of HED fuel with renewable biomass feedstocks is highly appealing. But currently, most of the synthetic biofuels, due to their intrinsic ring structure, are incapable of competing with JP-10 in terms of energy density and freezing point. By emulating the structural characteristic of JP-10, we herein design and prepare a special C₁₆ fused tetracyclic biofuel using renewable cyclopentanone and benzoquinone as feedstocks. Key to success depends on selective dehydration of vicinal diol (dimer of cyclopentanone) over Amberlyst-15 in [Hmim]Cl. The Amberlyst-15/[Hmim]Cl system effectively suppresses the dominant pinacol-type rearrangement pathway and also exhibits good reusability for the dehydration. The hydrogen-bonding interaction between vicinal diol and imidazolium ring, as well as electrostatic force between carbocation intermediate and chloride anion contribute to the high diene selectivity. The compact ring framework gives rise to a density of 0.966 g/mL, combustion heat of 43.1 MJ/L, freezing point of ‒67 °C, and kinematic viscosity of 12.4 cSt, which are comparable to the properties of JP-10. It is expected that this as-prepared HED biofuel may potentially serve as a renewable alternative to petroleum fuel JP-10.