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: Ps [Pa]=1014.0⋅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 (1.9×10−3 Torr). It is concluded that high volatility of cyanuric triazide is caused by its low sublimation heat.