Diels–Alder Cycloaddition of Cyclopentadiene\nwith α‑Olefins for the Synthesis of High-Performance\nSustainable Aviation Fuels

A series\nof alkyl-substituted bicycloheptanes were synthesized\nby Diels–Alder cycloaddition of cyclopentadiene and C5–C8\nα-olefins. The reactions were conducted with three equivalents\nof the α-olefin to ensure a high conversion to the cross-coupled\nproduct and did not require the use of a solvent or catalyst. The\nresulting products were then hydrogenated over 10% Pd/C and distilled\nto yield jet fuel blendstocks. The saturated hydrocarbons exhibited\ndensities ranging from 0.861 to 0.872 g mL<sup>–1</sup> (11.1–12.5%\nhigher than the lower limit for Jet-A), gravimetric net heats of combustion\nranging from 42.8 to 43.3 MJ kg<sup>–1</sup> (comparable to\nJet-A), and −20 °C kinematic viscosities ranging from\n5.49 to 18.00 mm<sup>2</sup> s<sup>–1</sup>. Cyclopentadiene\ncan be readily derived from crude biomass sources including hemicellulose,\nwhile C<sub>5</sub>–C<sub>8</sub> olefins can be produced from\nbiomass through Fischer–Tropsch catalysis or oligomerization\nof bio-based ethylene. Thus, this work provides a route to generate\nmolecularly designed biosynthetic fuels with potential applications\nas blending agents to increase the performance of sustainable aviation\nfuels.