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–.