Synthesis, characterization, pyrolysis and thermokinetic studies of an energetic ionic liquid: 4-amino-1-methyl-1,2,4-triazolium nitrate

Abstract

Energetic ionic liquids (EILs) are continuously being explored in the field of energetic materials and are attractive candidates for use in explosives and propellants. A promising energetic ionic liquid viz., 4-amino-1-methyl-1,2,4-triazolium nitrate (AMTN) was synthesized and characterized by FT-IR, elemental, TG, LC-MS and ESI-MS analyses. The thermal decomposition of AMTN was studied by non-isothermal thermogravimetric analysis (TGA) under variable heating rates from 5 to 20 °C/min. The TG data of AMTN showed a single stage decomposition in the temperature range of 180–260 °C. Pyrolysis GC–MS studies were undertaken at 300 °C and the major decomposition fragments were identified as nitrous oxide (N₂O), aziridine 1-amine, 1,2,3-triazine and 1-methyl-1,2,4-triazole and a mechanism was evolved. The activation energy (E_a) for the thermal decomposition of AMTN was evaluated using Kissinger method and is found to be 126.6 ± 14.1 kJ/mol. Kinetic analyses using isoconversional method of Vyazovkin, showed a strong dependence of E_a on fractional conversion (α).