SYNTHESIS AND CHARACTERIZATION OF HOMEMADE EXPLOSIVES

Abstract

Homemade explosive (HME) is a general term used to encompass energetics easily prepared from materials that consumers can purchase, but because of sensitivity, stability, and/or performance, often have no legitimate commercial or military use. HME preparation has been described in many books and message board threads for years with varying levels of detail and correctness. The class of HMEs is broad and includes fuel/oxidizer mixtures (e.g. ammonium nitrate/fuel oil or ANFO), nitrate esters (e.g. erythritol tetranitrate, ETN), and peroxides (e.g. triacetone triperoxide, TATP). Though the energetic properties for many of these compounds have been known for over a century, they are still studied today. Often focus is on detection schemes that can be applied to field techniques to be used at checkpoints or for ensuring that canine training aids are safe and reflective of the target molecule. With improvements to analytical instrumentation, new detection schemes are being explored today. Sometimes studying the synthesis of these materials could drive legislation towards control of some precursors if the threat is deemed high enough. One broad class of HMEs that is prevalent are nitrate esters. Nitrate esters are molecules that generally have carbon backbones with multiple -ONO2 groups present on the molecule. Nitroglycerin (NG) and pentaerythritol tetranitrate (PETN) are two examples of nitrate esters that have legitimate uses and are quite common. Both are prepared from the nitration of their corresponding sugar alcohols. The availability of the sugar alcohols. in large amounts has been a driving force for the popularity of some of the compounds. As consumers move towards healthier sugar-free alternatives, the availability of sugar alcohols, such as erythritol, xylitol, mannitol, and sorbitol has become widespread. Through simple nitration reactions, these sugar alcohols can be readily converted into explosives with good performance. One of the most common of these nitrate ester HMEs is erythritol tetranitrate (ETN). While it currently has no military applications, it melting point of 60°C makes it a melt-castable material that, if decomposition and sensitivity issues can be handled, continues to remain relevant. Since erythritol is readily nitrated, ETN is common in hobbyist chemist circles and message boards. With a forensics group in the Netherlands, a large study was undertaken to explore whether or not product ETN could be traced back to synthesis methods. Crude and recrystallized ETN were prepared via two synthesis routes, the nitrate salt method (MNO3 and sulfuric acid) and the mixed acid route (HNO3 and