Determination of the energies of combustion and enthalpies of formation of nitrobenzenesulfonamides by rotating-bomb combustion calorimetry

The energies of combustion for 2-nitrobenzenesulfonamide (cr), 3-nitrobenzenesulfonamide (cr), and 4-nitrobenzenesulfonamide (cr) were determined using a recently described rotating-bomb combustion calorimeter. The condensed phase molar energies of combustion obtained were -(3479.2 ± 1.0) kJ . mol-1 for 2-nitrobenzenesulfonamide (cr), -(3454.2 ± 1.1) kJ . mol-1 for 3-nitrobenzenesulfonamide (cr), and -(3450.1 ± 1.9) kJ . mol-1 for 4-nitrobenzenesulfonamide (cr). From these combustion energy values, the standard molar enthalpies of formation in the condensed phase were obtained as: -(341.3 ± 1.3) kJ . mol-1, -(366.3 ± 1.3) kJ . mol-1, and -(370.4 ± 2.1) kJ . mol-1, respectively. Polyethene bags were used as an auxiliary material in the combustion experiments. The heat capacities and purities of the compounds were determined using a differential scanning calorimeter.