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 × 10(12) 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(-).