ENTHALPIES OF COMBUSTION OF 2,4,6-TRIMETHYLBENZONITRILE, 2,4,6-TRIMETHYLBENZONITRILE N-OXIDE, 2,6-DIMETHYLBENZONITRILE, 2,4,6-TRIMETHOXYBENZONITRILE, AND 2,4,6-TRIMETHOXYBENZONITRILE N-OXIDE - THE DISSOCIATION ENTHALPIES OF THE (N-O) BONDS

The standard (p° = 0.1 MPa) molar enthalpies of combustion at 298.15 K were measured by static-bomb calorimetry and the standard molar enthalpies of sublimation at 298.15 K were measured by microcalorimetry for the following aromatic nitriles and aromatic nitrile N-oxides: (2, 4, 6 - Trimethylbenzonitrile 5530.7 ± 0.9 82.9 ± 1.6; 2, 4, 6 - Trimethylbenzonitrile N -oxide 5563.1 ± 0.8 77.5 ± 3.7; 2, 4, 6 - Trimethoxybenzonitrile 5150.0 ± 0.9 112.6 ± 2.0; 2, 4, 6 - Trimethoxybenzonitrile N -oxide 5187.1 ± 1.6 91.9 ± 1.9; 2, 6 - Dimethylbenzonitrile 4890.1 ± 1.0 83.9 ± 2.8). From the standard molar enthalpies of formation of the gaseous compounds, the molar dissociation enthalpies of the (N{single bond}O) bonds were derived: D(N{single bond}O)/(kJ·mol-1) trimethylbenzonitrile N-oxide, (222.2 ± 4.6); trimethoxybenzonitrile N-oxide, (232.8 ± 3.8). © 1991 Academic Press Limited All rights reserved.