Thermodynamic Properties of Energetic Plasticizers: Experimental Vapor Pressures of Methyl-, Ethyl-, and Butyl-Nitroxyethyl Nitramines

Abstract

In this work, experimental vapor pressures of the commonly used energetic plasticizers methyl-NENA, ethyl-NENA, and butyl-NENA were measured for the first time with a transpiration method. The p–T fitting equations and the corresponding molar enthalpies of phase transitions at 298.15 K are reported: the molar enthalpies of sublimation and vaporization of methyl-NENA were measured to be 104.5 ± 0.9 and 82.0 ± 1.1 kJ·mol–1, respectively. The consistency of these results was examined by the differential scanning calorimetry experiment, which yielded the molar enthalpy of fusion at 298.15 K to be 23.8 ± 0.3 kJ·mol–1. The molar enthalpies of vaporization at 298.15 K for ethyl- and butyl-NENAs were derived to be 79.8 ± 0.4 and 85.9 ± 0.5 kJ·mol–1, respectively. The p–T fitting equations were extrapolated at 298.15 K, and the corresponding results were reported in this work.