Diels–Alder Cycloaddition of Cyclopentadiene with α-Olefins for the Synthesis of High-Performance Sustainable Aviation Fuels

Abstract

A series of alkyl-substituted bicycloheptanes were synthesized by Diels–Alder cycloaddition of cyclopentadiene and C5–C8 α-olefins. The reactions were conducted with three equivalents of the α-olefin to ensure a high conversion to the cross-coupled product and did not require the use of a solvent or catalyst. The resulting products were then hydrogenated over 10% Pd/C and distilled to yield jet fuel blendstocks. The saturated hydrocarbons exhibited densities ranging from 0.861 to 0.872 g mL^–1 (11.1–12.5% higher than the lower limit for Jet-A), gravimetric net heats of combustion ranging from 42.8 to 43.3 MJ kg^–1 (comparable to Jet-A), and −20 °C kinematic viscosities ranging from 5.49 to 18.00 mm² s^–1. Cyclopentadiene can be readily derived from crude biomass sources including hemicellulose, while C₅–C₈ olefins can be produced from biomass through Fischer–Tropsch catalysis or oligomerization of bio-based ethylene. Thus, this work provides a route to generate molecularly designed biosynthetic fuels with potential applications as blending agents to increase the performance of sustainable aviation fuels.