Initiation reactions Intrinsic activation energy

Thus, the elementary cellular structure could be regarded as an intrinsic characteristic of fhe detonation in a mixture at given initial composition, temperature, and pressure. The dimension of X is of fhe order of magnitude of millimeters or less for gaseous mixfures with oxygen, but several centimeters for less sensitive mixtures (even larger, for methane/air af afmospheric pressure). It decreases when the initial pressure increases. Its variation with the initial temperature is more complicated and depends on the value of fhe reduced activation energy of fhe chemical reactions. The value of... 

Sensitivity is a parameter which determines how easily a fast reaction can be initiated in a sample, usually at normal temperature and pressure. It should be simply relatable to the activation energy shown in Figure 1. However, because of the temperamental behavior, it is often expressed as a probability that a fast reaction will result, and specific attempts are made to constrain the stimulus to one of several pressure-temperature-time profiles which have proved to be convenient to use in a laboratory environment (see Chapters 4,5, and 6 of Volume 2). Unfortunately, the energy present in a stimulus is often not repro-ducibly deposited in samples, and the environment or confinement of samples also affects the response. Thus, sensitivity as measured is commonly not an intrinsic property of an explosive and is not well-defined quantitatively. 

It was demonstrated that in the case of benzene oxidation, the intrinsic reactivities of all potential extra-framework complexes for benzene activation, the initial dissociation of N O, and the final phenol formation were very similar. The eneigetics of elementary reactions steps were influenced only sUghtly by the nature and the structural properties of the catalytic site. Representative reaction energy diagrams for the mononuclear Fe + and Fe sites are shown in Fig. 8. 

---