THERMAL-DECOMPOSITION OF ENERGETIC MATERIALS .35. A MECHANISM STUDY OF DECOMPOSITION AND THE IGNITION-LIKE TRANSITION IN TRINITROMETHYL ALKYL-COMPOUNDS

Chemical features of the mechanism of the apparent transition from decomposition to deflagration frequently observed in compounds containing the trinitromethyl group have been elucidated by using rapid-scan FTIR spectroscopy with temperature profiling as a function of pressure. The compounds studied were [(NO2)3CCH2O]xCH44-x, x = 2-4 (TEFO, TNEOF, TNEOC, respectively). TEFO, TNEOF, and TNEOC were studied in the most detail. They melt 40°C or more below the decomposition point when rapidly heated (70°-200°C/s). The first detected thermolysis step is homolysis of a few CCO2 bonds per molecule liberating NO2(g). The temperature at which this occurs at 15 psi Ar is TEFO (145°C) < TNEOF (180°C) < TNEOC (200°C), which is consistent with CC bond scission also occuring in the condensed phase. The resultant residue exotherms in a narrow temperature range (230°-250°C) irrespective of the static pressure (15-1000 psi Ar) or the orginal sample. This indicates that the ignition-like step involves the residue alone in the condensed phase without participation of the initially released NO2(g). © 1990.