Decomposition Kinetics of Nitroglycerine·Cl–(g) in Air at Ambient Pressure with a Tandem Ion Mobility Spectrometer

A dual-shutter ion mobility spectrometer operating at atmospheric pressure and interfaced to a gas chromatograph for sample introduction has been used to study the reaction of Cl– with explosives. Of particular interest was an investigation of the formation of NO3 – from the reaction of the Cl– with nitroglycerin (NG). The adduct NG·Cl– together with NO3 – and NG·NO3 – compose the mobility spectrum. Over the temperature range 111 to 122 °C, NG·NO3 – is stable, but NG·Cl– decomposes to NO3 – and 1,2-dinitro-3-chloropropane (DNClP). The activation energy and pre-exponential factor for this first order decomposition are 80 ± 3 kJ mol–1 and 1.3 × 1012 s–1, respectively. Ab initio calculation shows that the reaction is a substitution reaction occurring over a two well potential energy profile with stable ion–molecule complexes NG·Cl– and DNClP·NO3 –.