Thermochemical properties of N-heterocyclic compounds III. Enthalpies of combustion, vapour pressures and enthalpies of sublimation, and enthalpies of formation of 9H-carbazole, 9-methylcarbazole, and 9-ethylcarbazole

The energies of combusion of 9H-carbazole, 9-methylcarbazole, and 9-ethylcarbazole have been measured using a static bomb calorimeter. The vapour pressures have been determined over a temperature range of about 15 K by the Knudsen-effusion technique. From the experimental results the following quantities for the three compounds at 298.15 K have been derived: Compound kJ · mol−1 kJ · mol−1 kJ · mol1 9H-Carbazole 101.7±2.8 103.3±1.1 205.0±3.0 9-Methylcarbazole 103.7±2.4 95.5±0.3 199.2±2.4 9-Ethylcarbazole 70.6±2.6 99.1±0.3 169.7±2.6The support of the Spanish CICYT under Project PB0227 is gratefully acknowledged