Thermodynamics Research Center / ThermoML | Journal of Chemical Thermodynamics

ABSTRACT

The energetic study of 4-nitro-2,1,3-benzothiadiazole has been developed using experimental techniques together with computational approaches. The standard (p = 0.1 MPa) molar enthalpy of formation of crystalline 4-nitro-2,1,3-benzothiadiazole (181.9 +- 2.3 kJ mol-1) was determined from the experimental standard molar energy of combustion (3574.3 +- 1.3) kJ mol-1, in oxygen, measured by rotating-bomb combustion calorimetry at T = 298.15 K. The standard (p = 0.1 MPa) molar enthalpy of sublimation, at T = 298.15 K, (101.8 +- 4.3) kJ mol-1, was determined by a direct method, using the vacuum drop microcalorimetric technique. From the latter value and from the enthalpy of formation of the solid, it was calculated the standard (p = 0.1 MPa) enthalpy of formation of gaseous 4-nitro-2,1,3-benzothiadiazole as (283.7 +- 4.9) kJ mol-1. Standard ab initio molecular orbital calculations were performed using the G3(MP2)//B3LYP composite procedure and several working reactions in order to derive the standard molar enthalpy of formation 4-nitro-2,1,3-benzothiadiazole. The ab initio results are in good agreement with the experimental data.