EXPERIMENTAL AND NUMERICAL-STUDIES OF THE COMBUSTION OF DITERTIARY BUTYL PEROXIDE IN THE PRESENCE OF OXYGEN AT LOW-PRESSURES IN A MECHANICALLY STIRRED CLOSED VESSEL

The decomposition of di-t-butyl peroxide in the presence of oxygen leads to two distinct modes of thermal ignition. In this study under closed, mechanically stirred conditions, we reveal the main experimental distinctions between the single-stage, blue ignition, during which the temperature rises by only ca 400 K, and the two-stage, hot ignition, during which the temperature rises to a normal adiabatic limit. The final products of combustion are distinguished by use of mass spectrometry. We map the (p-Ta) regions for the existence of these phenomena, and comparisons are also made with the location of the ignition boundary for decomposition in the absence of oxygen. The evolution of the ignition phenomena (including thermocouple and mass spectrometer records) were simulated by numerical analysis of a thermokinetic model comprising 69 reactions involving 27 species. The ignition diagram is reproduced from the calculations. The location of the boundary between single- and two-stage ignition appears to be very sensitive to the Arrhenius parameters of the equilibrium CH3 + O2 = CH3O2. The origins of the second stage of hot ignition are traced to the further oxidation of the intermediate, molecular products hydrogen peroxide and formaldehyde and the accompanying heat release. Acetone is also oxidized, but only as a consequence of the rising temperature and radical concentrations during the second stage. There is a striking similarity of the present experimental results to those from the oxidation of ketene, reported by Michaud et al. [Combust. Flame 12:395 (1965)]. Relationships to hydrocarbon oxidation are also discussed. © 1990.