The standard molar enthalpies of combustion and formation of 2-methylbenzothiazole, 2-methylbenzoxazole, and 2-methyl-2-thiazoline

Abstract

A static-bomb combustion calorimeter and a rotating-bomb combustion calorimeter were used to determine the energies of combustion of 2-methylbenzothiazole, 2-methylbenzoxazole, and 2-methyl-2-thiazoline. The static- and rotating-bomb calorimeters were recently calibrated by the standard benzoic acid combustion runs and they were tested with adequate secondary combustion standards. The rotating-bomb calorimeter was tested using thianthrene and, in the present work, 1,2,4-triazole was used to test the static-bomb calorimeter. From the energies of combustion of the compounds under study, the liquid-phase standard molar enthalpies of formation were derived, at T = 298.15 K, as: (72.5 ± 1.5), (−50.7 ± 2.1), and (−88.5 ± 2.8) kJ mol−1, respectively.