Synthesis and Performance of Strained Multicyclic Hydrocarbons as Highly Potential High-Energy-Density Fuels

The rapid development of aerospace technology puts forward the urgent needs for fuels with higher energy density and good cryogenic and ignitable properties. Herein, we applied an RCOOZnCH2I-mediated cyclopropanation to synthesize four three-membered cyclic fuels with ca. 100% yield through optimizing the reaction conditions including substituent groups in zinc carbenoids, carbenoid/substrate ratio, and solvents. The fuels show the volumetric heat of combustion to be 3.6–11.7% higher than the currently used fuel JP-10 and low freezing point and viscosity. The advantages of strained fuels with regard to increasing the energy density while maintaining good low-temperature fluid properties are illustrated through comparison with conventional cyclic fuels. Moreover, the strained fuels exhibit low ignition temperature and short ignition delay. This work suggests that the strained fuels are highly promising as advanced high-energy-density fuels.