Halogen substitution on PETN framework: An energetic material sensitivity study

Evaluating explosives for safety properties is critical in order to develop safe handling, transport, and storage requirements. Literature reports have provided evidence that many factors can influence sensitivity, including chemical effects such as functional groups, bond connectivity, and thermal decomposition. Additionally, macroscale effects such as crystal structure, hydrogen bonding, electrostatic effects and co-crystallization can play important roles. Herein we describe work in which the explosive PETN (pentaerythritol tetranitrate) has been modified though systematic substitution of the nitrate ester groups with halogens (Cl, Br, I). All PETN derivatives with a single halogen substitution exhibited similar explosive sensitivities, despite differences in their crystal packing properties. Results from these experiments suggest that when dealing with sensitive explosives, i.e. nitrate esters, chemical structure and bond connectivity are more important in determining properties than secondary effects such as crystal packing. Both the presence and quantity of the weakest bond, in this case the O-NO₂ “trigger linkage,” can be the most important factor in determining the ability of the explosive to generate and sustain a measurable reaction in small-scale sensitivity testing.