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Deuterium Isotope Effects during HMX Combustion: Chemical kinetic burn rate control mechanism verified
Author(s) -
Shackelford S. A.,
Goshgarian B. B.,
Chapman R. D.,
Askins R. E.,
Flanigan D. A.,
Rogers R. N.
Publication year - 1989
Publication title -
propellants, explosives, pyrotechnics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.56
H-Index - 65
eISSN - 1521-4087
pISSN - 0721-3115
DOI - 10.1002/prep.19890140303
Subject(s) - deflagration , combustion , kinetic isotope effect , chemistry , deuterium , burn rate (chemistry) , thermodynamics , decomposition , chemical kinetics , reaction mechanism , hydrogen , reaction rate , thermal decomposition , kinetic energy , kinetics , organic chemistry , detonation , explosive material , physics , quantum mechanics , catalysis
The appearance of a significant deuterium isotope effect during the combustion of the solid HMX compound verifies that the chemical reaction kinetics is a major contributor in determining the experimentally observed or global burn rate. Burn rate comparison of HMX and its deuterium labeled HMX‐d 8 analogue reveals a primary kinetic deuterium isotope effect (1° KDIE) at 500 psig (3.55 MPa) and l000 psig (6.99 MPa) pressures and selectively identifies covalent carbon‐hydrogen bond rupture as the mechanistic step which ultimately controls the HMX bum rate under the static combustion conditions of this experiment. The 1° KDIE value further suggests the rate‐limiting CH bond rupture occurs during the solid state HMX decomposition/deflagration portion of the overall combustion event and is supported by other independently published studies. A possible anomalous KDIE result at 1500 psig (10.4 MPa) is addressed. This condensed phase KDIE approach illustrates a direct link between lower temperature/pressure thermal decomposition and deflagration processes and their potential applicability to the combustion regime. Most importantly, a new general method is demonstrated for mechanistic combustion investigations which selectively permits an in‐situ identification of the compound's burn rate‐controlling step.