Synthesis of caged high-energy-density fuel as potential high-performance energetic additive for liquid aerospace fuel

High-energy-density (HED) fuels have drawn substantial attention for volume-limited aerospace vehicles because they can provide high propulsion energy. Herein, we report a route for synthesis of HED fuel pentacyclo[5.3.0.0 2,5 .0 3,9 .0 4,8 ]decane (PCD) with strained structure by photoinduced intramolecular [2 + 2] cycloaddition of dicyclopentadiene (DCPD). The reaction conditions, like photosensitizer , solvent, concentration, temperature and light intensity , were optimized for achieving the best photochemical performance, with the high DCPD conversion of 95.89% and high PCD selectivity of 62.08%. The triplet quenching and phosphorescence quenching results show that DCPD cycloaddition proceeds under the photosensitizer photoexcitation , triplet-triplet energy transfer, cyclization and relaxation. Moreover, a reaction kinetic model is established with the reaction rate constant being correlated with light intensity, with the pseudo reaction kinetics parameters and reaction rate equations obtained. As a caged fuel, PCD possesses both high density (1.066 g/cm 3 ) and high volumetric neat heat of combustion (44.43 MJ/L), which is very promising to blend with current high density liquid fuels to obtain high-performance fuels for practical application.