Thermal Decomposition of Energetic Materials. 8. Evidence of an Oscillating Process during the High-Rate Thermolysis of Hydroxylammonium Nitrate, and Comments on the Interionic Interactions

Article abstract of DOI:10.1021/j100273a040

Relatively dry, solid hydroxylammonium nitrate (HAN), (NH3OH)NO3, was examined by IR spectroscopy from 170 K to well above its decomposition point.The modes in the 2600-2950-cm^-1 range are assigned to -NH3(1+) combination tones, rather than to ν(OH) as was recently proposed for aqueous HAN solutions.Frequency-to-distance correlations for solid HAN cast doubt on the viability of using ν(NH/OH) fundamentals to determine accurate interionic distances in HAN.Several of the thermolysis products of HAN (HNO3, N2O, and NO2) were quantified in real time by rapid-scan FTIR and were found to oscillate when solid HAN and aqueous HAN solutions were pyrolyzed at a high rate (130 K s^-1) with pressures <*> 100 psi of Ar.The onset of the oscillation is delayed by increasing the initial H2O content.The period of oscillation at constant pressure increases with the heating rate.Some comments on the reactions that may lead to the decomposition products of HAN are made based on these findings.