Mechanisms of nitramine decomposition: very low-pressure pyrolysis of HMX and dimethylnitramine. Final report
The very low-pressure pyrolysis (VLPP) of cyclotetramethylenetetranitramine (HMX) and dimethylnitramine have been studied over the temperature ranges 530 to 645/sup 0/K and 550 to 840/sup 0/K, respectively. High pressure limit Arrhenius parameters for HONO elimination and N-NO/sub 2/ bond scission in dimethylnitramine have been determined to be log k(sec/sup -1/) = 12.4 +- 0.8 - (37 +- 1.8)/2.3 RT and log k(sec/sup -1/) = 16.5 +- 0.8 - (48.5 +- 1.8)/2.3 RT, respectively. Use of the dimethylnitramine decomposition parameters as models for HMX decomposition suggests that HONO elimination and N-NO/sub 2/ bond scission should have equal rates at about 600/sup 0/K. Above this temperature, N-NO/sub 2/ bond scission will become increasingly predominant. The observed temperature dependence of HMX decomposition is consistent with an activation energy less than or equal to 40 kcal/mole, but the data are too scattered to completely rule out the 45.50 kcal/mole which would signify initial N-NO/sub 2/ bond scission. The decomposition of HMX yields m/e 46 as a major initial product mass, consistent with either pathway, but not consistent with either concerted or stepwise depolymerization as the probable initial step(s) in HMX decomposition.
- Research Organization:
- SRI International, Menlo Park, CA (USA)
- OSTI ID:
- 6058341
- Report Number(s):
- SAN-0115/117
- Country of Publication:
- United States
- Language:
- English
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