Activation energy nitroglycerine

Fortunately, explosives have an activation energy, so it takes some energy to get the reaction started. Usually, what starts the reaction is heat, but it can be a physical shock for especially sensitive explosives like liquid nitroglycerin. 

The diffusion coefficients of nitroglycerin and triacetin in doublebase propellant have been measured at 77°-140°F. Activation energies for diffusion ranged from 10 to 13 kcal./mole. Thus, cure rates for a given propellant composition can be expected approximately to double in going from 120° to 140°F. 

The activation energy E needed for the thermal decomposition of nitroglycerine was calculated by T. Urbanski and Rychter to be ... 

The first of those values is of the same order as those obtained by other authors. Thus considering the numeral data of Robertson [62] and Will [66] the following values of the activation energy necessary to decompose nitroglycerine were reported by Semenov [67] ... 

This has been confirmed in a recent reports by Andreyev, Glaskova, Maurina and Svetlov [60], According to these authors the activation energy of nitroglycerine decomposition at 140-150°C is E = 45.0 kcal/mole (log10 B = 20). 

Another problem is its thermal decomposition. T. Urbanski and Rychter [44) examined the decomposition at temperatures near 400 C and above. The errergy of activation between 3H0 440 ( was of the order of 14 kcal/mol. Between 490 and 750 C trinitrotoluene took spherical shape and decomposed slowly w iih the evolution of a considerable amount of soot. Tlie energy of activation in the range of temperatures 490 750 C was of the order of 8 kcal/mol and the shape of the curve induction period against temperature was analogous to that shown for nitroglycerine in Vol. II. p. 50. Fig. 13. 

M. For some explosives, A is larger than v. For nitroglycerine, A = 1,020 and E is also a large number E = 179,912 J/mol). The speeds of evaporation and activation still follow the above conditions. It is concluded that the transferred heat evaporates the liquid molecules. The evaporation is much faster than reaction in the liquids. Evaporation processes absorb both the transferred energy and the released energy from reactions. The schematics of evaporation-combustion are shown in Fig. 2.2. 

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