Enthalpies of combustion and formation of phenazine and 2,1,3-benzoxadiazole

Abstract

By means of a conventional adiabatic bomb calorimetry, the enthalpies of combustion of crystalline C 12H 8N 2 (phenazine) and C 6H 4N 2O (2,1,3-benzoxadiazole) have been determined to be 6109.1 and 3168 kJ mol −1, respectively. Also be means of transpiration and Knudsen-effusion mass-spectrometric methods, the enthalpies of sublimation were determined. The values obtained are 99.9 kJ mol −1 for C 12H 8N 2 and 64.9 kJ mol −1 for C 6H 4N 2O. From these values and thermochemical data, the CN and ON bond-energy terms, in condensed aromatic rings, have been calculated to be 439 and 284.5 kJ mol −1, respectively.