Gaseous Detonations. III. Dissociation Energies of Nitrogen and Carbon Monoxide

Detonation velocities have been measured in mixtures of cyanogen and oxygen at several pressures and in tubes of several diameters, with a reproducibility of the order of 0.1 percent. Thermodynamic calculations of detonation velocities were carried out for several assumed heats of dissociation of nitrogen and of carbon monoxide and for several experimental conditions. Methods are described for the extrapolation of experimental velocities to the limit of an infinite plane wave in ideal gases. The comparison of these extrapolations with thermodynamic calculations gives best agreement for DN2=9.76 ev and DCO=11.11 ev, the difference of experimental and calculated velocities averaging to 0.08 percent, with a standard deviation of 0.3 percent, which agrees with the predicted standard deviation. Several lower dissociation energies, which have been recommended on the basis of spectroscopic studies and of appearance potentials, give such poor agreement with these experimental data that they constitute very strong evidence in favor of the higher dissociation energies.