On the use of the generalized autocatalytic models: The thermal decomposition of 3,5‐dinitro‐4‐methylbenzoic acid

Abstract

The thermal decomposition of 3,5-dinitro-4-methylbenzoic acid is studied by means of differential calorimetric techniques (DSC). Its autocatalytic behaviour has been highlighted and the decomposition process has been described considering the generalized expression of the Sest ak-Berggren model. A new procedure for the optimization of the initiation parameter along with the other Arrhenius constants and kinetic exponents starting from the knowledge of the classic Sest ak-Berggren model is illustrated. Encouraging results point out the validity of the approach which has been verified considering both a series of numerical and real experiments.

Shelf Life Prediction of Picric Acid via Model-Based Kinetic Analysis of Its Thermal Decomposition

“…Figure 2 shows the results of a set of dynamic differential scanning calorimetry (DSC) experiments carried out on PA at heating rates of 2.5, 10, and 20 • C min −1 in terms of curves "specific (i.e., referring to the mass of sample) heat power, q, versus temperature" (mean curves). The presence of intersection points (A, B, and C) between two curves obtained at different heating rates reveals the autocatalytic nature of the thermal decomposition of PA [15,16], confirming previous findings (see, e.g., [13]).…”

“…where q(t) is the specific heat power as a function of time (isothermal and dynamic conditions) and q(T) is the specific heat power as a function of temperature (dynamic conditions). The autocatalytic nature of the process under examination is further confirmed by the sigmoidal shape of these conversion curves [15,16]. Consistently with this nature, the following expression of f(α) was assumed in Equation (1) [16]:…”

Adiabatic time to maximum rate evaluation using an analytical approach

“…In Figure the experimental mean curves collected during the DSC dynamic runs carried out on TA at the different heating rates are reported. The analysis of these data, due to the absence of self‐intersections among the curves suggests the validity of a reaction order kinetic model (Eq. ) and the application of the identification procedure described in detail in Ref.…”

“…The real data refer to the adiabatic thermal decomposition of Trityl Azide (TA), a compound considered, due to its reproducible behavior, as a possible candidate for the calibration of calorimetric devices . The necessary thermokinetic parameters for the thermal decomposition of TA have been determined by means of a suitable multivariate identification procedure carried out considering a set of dynamic DSC experiments performed at different heating rates. Finally, in order to verify the reliability of the developed method, adiabatic times to maximum rates evaluated both from numerical experiments and measured during the real runs have been compared with the values calculated by means of the Eq.…”

“…and the application of the identification procedure described in detail in Ref. allowed the assessment of the kinetic parameters reported in Table .…”