Volatilization interference in thermal analysis and kinetics of low-melting organic nitro compounds

Volatilization interference is the first prerequisite to be eliminated for the quantitative thermal analysis of low-melting material. The volatilization processes of three low-melting organic nitro compounds, TNT, DNAN and DNTF, were measured by isothermal thermogravimetry. The thermal decomposition behaviors and kinetics were studied by dynamic pressure measuring thermal analysis. The interference of the vapor pressure on the gas pressure of thermal decomposition at specified temperatures was deducted quantitatively. DNAN is the most stable, though three compounds all match the standard of good thermal stability. DNTF has the highest activity and is the most sensitive to heating under specified conditions. The surface changes caused by melting and thermal decomposition stimulate the reaction activity and affect the reaction kinetics and thermal stability. The reaction activity of the nitro compounds is directly related to the number of the nitro group/nitrogen atom.