COMPARATIVE MECHANISTIC THERMOCHEMICAL DECOMPOSITION ANALYSES OF LIQUID HEXAHYDRO-1,3,5-TRINITRO-1,3,5-TRIAZINE (RDX) USING THE KINETIC DEUTERIUM-ISOTOPE EFFECT APPROACH

The condensed phase kinetic deuterium isotope effect (KDIE) approach is applied to the thermochemical decomposition of liquid RDX and RDX-d6 using two dissimilar thermal analysis techniques. Comparative KDIE results from isothermal differential scanning calorimetry (IDSC) and from direct RDX concentration depletion measurements by quenched UV spectrometric analysis confirm the proposed proportionality between IDSC heat evolution rates and the RDX concentration depletion rate. Additionally, these KDIE data verify the proposed rate-controlling mechanistic step previously reported from an isothermal thermogravimetric investigation of liquid RDX determined from weight loss rates. Observed mechanistic and kinetic differences between the cyclic six-membered RDX decomposition and its eight-membered HMX homologue are outlined.