Gas-phase reaction of chlorine atoms with acrylonitrile. Temperature and pressure dependence

The kinetics and mechanism of the reaction of chlorine atoms with acrylonitrile (CH2CHCN) (1) have been studied by the mass spectrometric discharge-flow method in the temperature range (260–333) K and at a total pressure between 0.5 and 3 Torr. At 1.0 Torr the following Arrhenius expression for the rate constant has been obtained from the kinetics of Cl radical consumption in excess of CH2CHCN: k1=(5.2±1.6)×10−14exp[(1400±100/T)] cm3 molecule−1 s−1. The reaction is found to proceed through an addition mechanism involving a relatively stable adduct. The atmospheric significance of the present results for acrylonitrile is also discussed.