Thermochemical properties, thermal behavior and decomposition mechanism of 1,1-diamino-2,2-dinitroethylene (DADE)

The constant-volume combustion energy, Delta U-c (DADE, s, 298.15 K), the thermal behavior, and kinetics and mechanism of the exothermic decomposition reaction of 1, 1-diamino-2,2-dinitroethylene (DADE) have been investigated by a precise rotating bomb calorimeter, TG-DTG, DSC, rapid-scan fourier transform infrared (RSFF-IR) spectroscopy and T-jump/FTIR, respectively. The value of Delta H-c(M)theta (DADE, s, 298.15 K) was determined as (-8518.09 +/- 4.59) J(.)g(-1). Its standard enthalpy of combustion, Delta U-c (DADE, s, 298.15 K), and standard enthalpy of formation, Delta H-f(m)theta (DADE, s, 298.15 K) were calculated to be (-1254.00 +/- 0.68) and (-103.98 +/- 0.73) kJ(.)mol(-1), respectively. The kinetic parameters (the apparent activation energy E. and pre-exponential factor A) of the first exothermic decomposition reaction in a temperature-programmed mode obtained by Kissinger's method and Ozawa's method, were E-k=344.35 kJ(.)mol(-1), A(k)= 10(34.50) s(-1) and E-o=335.32 kJ(.)mol(-1), respectively. The critical temperatures of thermal explosion of DADE were 206.98 and 207.08 degrees C by different methods. Information was obtained on its thermolysis detected by RSFr-IR and T-jump/FFIR.