Forensic characterization of spontaneous acetone peroxide formation from consumer-aged 2-propanol

• Characterization of spontaneously generated TATP from isopropanol . • Differentiation of traditionally synthesized TATP from spontaneous formation. • Insights into the reaction mechanism of secondary alcohol to cyclic peroxide conversion. • Reaction byproduct characterization of spontaneously formed peroxides. Numerous instances of well-aged consumer-grade 2-propanol (isopropanol) containing solid primary explosive material have been reported and turned over to the authorities. Herein, one such sample that was turned over to the Bureau of Alcohol, Tobacco, Firearms and Explosives has been analytically characterized to understand the solid primary explosive material as well as the liquid composition for forensic purposes. Upon examination by several analytical methodologies, the liquid phase of the sample contained isopropanol with measurable amounts of species indicative of isopropanol degradation and precursors to triacetone triperoxide. These species included acetone, methanol, acetic acid, isopropyl acetate, hydroxy-propanone, linear acetone peroxides, several atypical linear acetone peroxides species, and cyclic acetone peroxides ( e.g., triacetone triperoxide). The solid material in the container was predominately triacetone triperoxide as well as diacetone diperoxide and tetraacetone tetraperoxide. Microscopic properties and x-ray powder diffractograms of the solid material recovered from the aged isopropanol differed from traditionally synthesized triacetone triperoxide. This comprehensive analysis serves as a reference and aid in analysis for forensic laboratories when alleged samples of spontaneously formed triacetone triperoxide are encountered.