THERMAL-DECOMPOSITION OF ENERGETIC MATERIALS .62. RECONCILIATION OF THE KINETICS AND MECHANISMS OF TNT ON THE TIME-SCALE FROM MICROSECONDS TO HOURS

An analysis is described of the kinetics and mechanisms of thermal decomposition of 2,4,6-trinitrotoluene (TNT) in the bulk phase. The basis is the decomposition kinetics of mono-, di-, and trinitrobenzene and the corresponding toluene derivatives in the temperature dimension. Below about 770-degrees-C (greater-than-or-equal-to 100 mus reaction time), the initiation chemistry is dominated by oxidation reactions of the methyl group. Above about 770-degrees-C C-NO2 homolysis dominates the initiation process. Shock initiation is therefore dominated by C-NO2 homolysis while -CH3 group oxidation and C-NO2 homolysis compete in controlling impact initiation. Neither of these processes controls the time-to-explosion at times longer than 0.1 s. Instead, time-to-explosion is controlled by catalysis from the decomposition products of TNT. This analysis reconciles conflicting observations and statements previously made about the chemical mechanisms that control the explosive behavior of TNT.