Thermochemistry of Evaporation and Sublimation of 2,4,6-Triazido-1,3,5-triazine

Saturated vapor pressure over cyanuric triazide melt was measured in the temperature range 393.15-453.15 K using glass membrane Bourdon pressure gauges. Measured evaporation heat and evaporation entropy are equal to 61.1 +/- 3.3 kJ mol(-1) and 111.3 +/- 6.1 J mol(-1) K-1, respectively. According to DSC data, melting heat and melting entropy of cyanuric triazide are 22.2 +/- 1.3 kJ mol(-1) and 60.5 +/- 3.5 J mol(-1) K-1, respectively. Based on the results obtained, the following dependence was found for the saturated vapor pressure over solid cyanuric triazide: P-s [Pa] = 10(14.0).exp[(-83300 +/- 3300)/RT]. Concequently, sublimation heat and sublimation entropy of cyanuric triazide are equal to 83.3 +/- 3.3 kJ mol(-1) and 171.8 +/- 9.6 J mol(-1) K-1, respectively. Saturated vapor pressure over solid cyanuric triazide at room temperature is equal to 0.25 Pa (1.9 x 10(-3) Torr). It is concluded that high volatility of cyanuric triazide is caused by its low sublimation heat.