A study of the kinetics and mechanisms involved in the atmospheric degradation of bromoform by atomic chlorine

Ab initio molecular orbital theory, in combination with FTIR spectroscopy, has been used to determine a second-order rate constant for the hydrogen abstraction reaction involving bromoform and chlorine atom. The rate constant for the reaction is determined to be 2.7±0.2×10−13 cm3 molecule−1 s−1 at 298 K. Ab initio molecular orbital theory calculations at the QCISD(T)/6-311G(d,p)//MP2/6-31G(d) level of theory predict the barrier for the hydrogen abstraction reaction to be 1.6 kcal mol−1. It has also been determined that, in the presence of oxygen, the reaction will lead to a one-to-one conversion of bromoform into carbonyl dibromide.