Experimental and theoretical studies of the CCl + O2 reaction

Elementary reaction of CCl radical with oxygen molecule has been investigated by time-resolved Fourier transform infrared emission spectroscopy. Product of CO was observed. The rate constant of this reaction is measured to be 2.6(±0.4) × 10−12 cm3 molecule−1 s−1. It is found that the nascent product of CO is highly vibrationally excited with an average vibrational energy of 17–18 kcal mol−1. DFT calculations at the B3LYP/6-311G(d) level reveal the reaction mechanism to be mainly a barrierless addition of O2 to CCl leading to a peroxide intermediate IM1 (ClCOO). The chain-like IM1 breaks its O–O bond and Cl–C bond sequentially, forming the product of CO.