Thermal kinetics and decomposition mechanism of 1-amino-1,2,3-triazolium nitrate

Abstract

The thermal decomposition kinetics of 1-amino-1,2,3-triazolium nitrate(ATZ-NO3) was investigated by non-isothermal TG-DTG at various heating rates(2, 5, 10, 15 and 20 °C/min). The results show that the thermal decomposition of ATZ-NO3 consist of two stages corresponding to the losing of nitrate anion, substituent group and the splitting of triazole ring respectively. The kinetic triplets of the two stages were described by a three-step method. First, the differential Kissinger and intergral Ozawa methods were used to calculate the apparent activation energies(E) and pre-exponential factors(A) of the two decomposition stages. Second, two calculation methods(intergral Satava-Sestak and differential Achar methods) were used to obtain several probable decomposition mechanism functions. Third, three judgment methods(average, double-extrapolation and Popescu methods) were used to confirm the most probable decomposition mechanism functions. Both reaction models of the two stages were random-into-nucleation and random-growth mechanisms with n=3/2 for the first stage and n=1/3, m=3 for the second stage. The kinetic equations for the two decomposition stages of ATZ-NO3 may be expressed as \(\frac{{da}} {{dt}} = 10^{13.60} \times e^{ - \frac{{128970}} {{RT}}} (1 - a)\left[ { - \ln (1 - a)} \right]^{ - \frac{1} {2}}\) and \(\frac{{da}} {{dt}} = 10^{11.41} \times e^{ - \frac{{117370}} {{RT}}} (1 - a)\left[ { - \ln (1 - a)} \right]^{\frac{2} {3}}\). The thermodynamic parameters including Gibbs free energy of activation(ΔG ≠), entropy of activation(ΔS ≠) and enthalpy of activation(ΔH ≠), for the thermal decomposition reaction were also derived.