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Mbah J.,Tuskegee University | Knott D.,Explosive Detection Equipment Program | Steward S.,Explosive Detection Equipment Program
Talanta | Year: 2014

This study aims at characterizing the vapor pressure signatures generated by triacetone triperoxide (TATP) that was synthesized without recrystallization by thermogravimmetric analysis (TGA) for exploitation by standoff detection technologies of explosive devices. The thermal behavior of the nonrecrystallized sample was compared with reported values. Any phase change, melting point and decomposition identification were studied by differential scanning calorimeter. Vapor pressures were estimated by the Langmuir method of evaporation from an open surface in a vacuum. Vapor pressures of TATP at different temperatures were calculated using the linear logarithmic relationship obtained from benzoic acid reference standard. Sublimation of TATP was found to follow apparent zero-order kinetics and sublimes at steady rates at 298 K and above. While the enthalpy of sublimation found, 71.7 kJ mol-1, is in agreement with reported values the vapor pressures deviated significantly. The differences in the vapor pressures behavior are attributable to the synthesis pathway chosen in this study. © 2014 Elsevier B.V. All rights reserved. Source

Mbah J.,Tuskegee University | Knott D.,Explosive Detection Equipment Program | Steward S.,Explosive Detection Equipment Program | Cornett D.,Explosive Detection Equipment Program
International Journal of Energetic Materials and Chemical Propulsion | Year: 2015

Vapor pressure and enthalpy of sublimation of triacetone triperoxide (TATP) that was synthesized using two different catalysts and without recrystallization were investigated by the gas chromatography headspace technique for exploitation in designing its detection remotely or using standoff capabilities. Vapor pressures and enthalpies of sublimation were calculated from the ideal gas and Clausius- Clapeyron equation, respectively. Good linearity of these equations implies that the enthalpy of sublimation is relatively constant over the temperature range studied. The enthalpies of sublimation were found to be 71 ± 4.8 and 65 ± 6.1 kJ mol-1 for TATP catalyzed by HCl and H2SO4, respectively. Also, the vapor pressures differed considerably for the chosen catalysts across the temperature range investigated, suggesting a vapor pressure and sublimation enthalpy dependency on the choice of catalyst used. Both values are in agreement with literature-reported vapor pressure data and enthalpies of sublimation (70–109 kJ mol-1). The study showed that TATP undergoes sublimation at steady rates at approximately 293 K and above. © 2015 by Begell House, Inc. Source

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