Effect of a chemical inhomogeneity on steady-state detonation velocity

The detonation behavior of the liquid explosive, nitromethane, sensitized by the liquid organic base, diethylene triamine, has been studied experimentally. The work to be described complements earlier work concerning the effect of physical impurities on steady detonation behavior. By interpretation of detonation-velocity measurements, the following three goals are reached: (1) The evidence that physical inhomogeneities (usually voids) produce the downward concave region of the diameter-effect curves of condensed high explosives is enhanced; (2) the hypothesis that homogeneous materials have linear diameter-effect curves is placed on a firmer basis; and (3) the experimental evidence indicates that the sensitizing material has altered the effective chemical kinetics and consequently, has produced an explosive with a shorter one-dimensional reaction zone. A remarkably small amount of the chemical impurity produces a significant reduction of the nitromethane failure diameter; e.g., addition of one molecule of the amine to 5500 molecules of nitromethane reduces the failure diameter by 43%. A discussion is given which attempts to relate this high sensitivity to a molecular isomer of nitromethane (the ''aci'' form) whose presence is favored in basic solutions