Thermal decomposition of new aldehyde-2,4-dinitrophenylhydrazone: Kinetic studies and thermal hazard predictions

Abstract

The thermal decompositions of acetaldehyde-2,4-dinitrophenylhydrazone and propionaldehyde-2,4-dinitrophenylhydrazone were studied using differential scanning calorimetry technique, in non-isothermal and isothermal regime. In non-isothermal linear regime, both model-fitting and model-free models were used. In isothermal regime, at several constant temperatures lower than the melting points, no decomposition was identified after more than three hours of isothermal time. The experimental curves were used to obtain the useful physical and thermodynamic melting and decomposition parameters. The activation parameters were obtained using model-free and isoconversional methods. Subsequently, the kinetic model of exothermal decomposition was established by means of multivariate non-linear regression analysis. An autocatalytic decomposition mechanism was found, a common characteristic of compounds with one or more nitro groups in their molecule. The isothermal prediction based on the assigned kinetic model and kinetic parameters were developed. Using similar data for several related compounds, previously reported, a discussion on the structure-properties relationship is proposed.