Thermal Decomposition of 1,3,5,5‐Tetranitrohexahydro‐Pyrimidine: A New Type of Autocatalysis that Persists at High Temperatures

Abstract

The thermal stability of 1,3,5,5-tetranitrohexahydropyrimidine (TNDA) in liquid phase under isothermal conditions was studied. It was established that the TNDA decomposition (k liq = 3.1 • 10 21 •exp(À 26865/T), E a = 223.4 kJ mol À 1) is accompanied by strong autocatalysis (k cat = 9.8 • 10 14 •exp(-18056/T), E a = 150.2 kJ mol À 1). The mechanism of autocatalysis was proposed. The essence of autocatalysis is the oxidation of TNDA by decomposition products, followed by the destruction of the molecule. An unusual feature of this autocatalysis is that, in contrast to autocatalysis of nitroesters, the process does not disappear at high temperatures, but rather determines the kinetics of heat release in the combustion wave. The surface temperature and combustion mechanism of TNDA were established through thermocouple studies. It was shown that the autocatalysis reaction at the surface temperature controls the burning rate.

Probing the Effects of Deuteration on the Structure and Thermal Behavior of TNT‐d5

“…In the initial stage of TNT decomposition, which is the non‐catalytic decomposition stage, nitrogen oxides will separate from the substrate and form nitrosonium ions. The single‐electron transfer between the nitrosonium ion and the TNT molecule will form a radical cation, which subsequently loses a proton to form a radical and undergoes further decomposition [25]. This mechanism is supported by the oxidation products of the methyl group in TNT (2,4,6‐trinitrobenzyl alcohol, 2,4,6‐trinitrobenzaldehyde, 2,4,6‐trinitrobenzoic acid) during TNT decomposition [12].…”

“…Therefore, the first‐order self‐accelerating reaction model (Eq. (2)) [25, 26] is used to calculate the reaction rate constants of TNT and TNT‐ d 5 . …”

“…A more recent theory can be further applied to this case [25]. It is well known that the nitration of aromatic compounds usually involves the single‐electron transfer from substrate to nitrosonium ions [28].…”

Monosubstituted Polynitroalkoxy‐1,2,4,5‐Tetrazines: A New Family of Melt‐Castable Energetic Materials

“…The decomposition of 3 c under isothermal conditions in a Bourdon manometer (140-172 °C) proceeds with a weak acceleration in time (Figure S22). It can be assumed that the acceleration is due to autocatalysis by the oxidation-reduction mechanism described in [25].…”

Effect of Aluminum on 1,3,5,5-tetranitrohexahydropyrimidine (DNNC) - A DFT Treatment

“…It was synthesized in 1982 and has the following properties; mp. 151-154C [3,4,5], density: 1.82 g/cm 3 , VOD: 8730 m/s, P CJ : 34 Pa, OB: 6%. It has very low impact sensitivity [6].…”