Characterization of thermal decomposition behavior of nitroaniline compounds with diverse functional groups by multiple calorimetric methods

Nitroaniline compounds as pivotal intermediates play a significant role in organic synthesis processes, including dyes, rubber additives, and agrochemicals. The published works mainly focused on the synthesis of nitroaniline compounds rather than the thermal decomposition behavior of nitroaniline compounds with diverse functional groups. The thermal decomposition behavior of six nitroaniline compounds was investigated by three calorimetric methods, while the differential scanning calorimetry data were employed to compute the decomposition reaction kinetic parameters by the Starink method. Fourier-transform infrared spectroscopy was used to characterize the adiabatic thermal decomposition products. Results reveal that six nitroaniline compounds show notable exothermic decomposition at high temperature. The decomposition kinetics results may be reveal autocatalytic character of the samples. The adiabatic thermal decomposition of gram-scale nitroaniline compounds exhibits significant heat release. The maximum temperature rise rates of 2-fluoro-4-nitroaniline and 4-nitroaniline are 1447.45 ℃ min⁻¹ and 905.69 ℃ min⁻¹, respectively. Fourier-transform infrared spectroscopy results reveal that residue of 2-fluoro-4-nitroaniline is aromatic ring polycondensation. The combination of multiple thermal analysis methods can comprehensively analyze the thermal decomposition risk of hazardous materials and provide some fundamental data.