Synthesis, thermal behaviors and thermal safety of 1,3-di (azido-acetoxy)-2-ethyl-2-nitropropane

Abstract

1,3-Di(azido-acetoxy)-2-ethyl-2-nitropropane (ENPEA) was synthesized from azidoacetic acid and 2-ethyl-2-nitro-1,3-propanediol. The thermal decomposition kinetics under pressures of 0.1 MPa and 3.0 MPa were investigated using differential scanning calorimetry (DSC). The thermal decomposition mechanism was studied by condensed-phase thermolysis/Fourier-transform infrared (FTIR) spectroscopy, simultaneous thermogravimetry (TG)-FTIR, and simultaneous TG-mass spectroscopy (MS) techniques. The activation energy under 3.0 MPa was found to be lower than that under 0.1 MPa. With increasing pressure, the decomposition heat increased significantly, while the peak temperature increased slightly. The non-isothermal kinetic equation of the exothermic process is dα/dT = 1012.5/β × 4(1-α)3/4exp (−1.449 × 105/RT) and the gas products are N2, NO2, NH3, HCN, CO2, and CH2O. Using the thermal decomposition parameters, the self-accelerating decomposition temperature and critical temperature of thermal explosion were calculated to be 191.4 °C and 204.4 °C, respectively. The specific heat capacity of ENPEA was studied by micro-DSC and the molar-heat capacity was found to be 570.9 J mol−1 K−1. Adiabatic time-to-explosion of ENPEA was calculated to be 18.2 s. These results are important in evaluating the thermal stability and application prospects of ENPEA.