Thermal decomposition of energetic materials. 23. thermochemical differentiation of cyclic and acyclic nitramines by their phase transitions

The sum of the values of ΔH measured by differential thermal analysis for the phase transitions from room temperature through the melting point for seven cyclic nitramines and nitrosamines is 35 ± 4 cal g−1. ΔSf for these compounds is 0.06 ± 0.03 cal deg−1 g−1. The values for ΣΔH and ΔSf for ten acyclic nitramines are 66 ± 18 cal g−1 and 0.17 ± 0.07 cal deg−1 g−1, respectively. The statistically significant difference between these two classes probably originates from the shape of the molecules. The disordered high-temperature phase of 1,4-dinitrofurazano[3,4-b]piperazine (DNFP), previously discovered by IR spectroscopy, is confirmed by DTA to be a plastic phase.