Synthesis and fuel properties of high-density and low-freezing-point asymmetric cycloalkyl adamantane

The exploration to increase the fuel energy density is stimulated by the payload and cruising range concerns in aerospace industry. The high-density fuels are always rationally designed for the advanced volume-limited aircrafts to fulfill more complicated missions. Alkyl adamantanes gradually become a prospective class of high-energy-density fuels. Herein, in this work, we reported an approach to synthesize asymmetric cyclopentyl adamantane via AlCl 3 -catalyzed alkylation of adamantane and cyclopentene with an attractive combination of a high density of 0.990 g/mL as well as a low freezing point of −30 °C. The obtained 1-cyclopentyl-adamantane was well designed with the cyclic substituent (enhance the density) and asymmetric structure (lower the freezing temperature). Subsequently, the comprehensive fuel performance of cyclopentyl adamantane, i.e. , density, freezing point, low-temperature viscosity, heating value , and combustion properties were evaluated. It was shown that both density and combustion properties of cycloalkyl adamantane were superior to the typical high-density JP-10 fuel. In addition, the properties of binary fuel mixture (1-cyclopentyl-adamantane and JP-10) demonstrated that cyclopentyl adamantane could be used as a promising blendstock with conventional jet fuel to enhance the energy density and promote the combustion performance of the final fuel blends.