Discharge flow reaction kinetic studies of O(3P) with chloroethylenes CH2CCl2, CHClCCl2, CCl2CCl2

The reaction of oxygen atoms [O(3P)] with chloroethylenes (RCl) viz. CH2CCl2, CHClCCl2, CCl2CCl2 was studied in a discharge flow set up in the pressure range of 1.2–1.5 Torr, employing the O(3P) chemiluminescence titration method. The bimolecular rate constant for the reactions O(3P)+RCl→products, are determined at room temperature to be (6.6±1.1)×10−13, (5.9±0.8)×10−13 and (1.9±0.3)×10−13 cm3 molecule−1 s−1 for CH2CCl2, CHClCCl2 and CCl2CCl2, respectively. Detailed ab initio calculations with the MNDO parametrization method 3 (PM3) are used to evaluate the kinetic and thermodynamic parameters. Formation of a biradical involving addition of an oxygen atom to the double bond is proposed as the major channel for the reaction. Unimolecular decomposition of the biradical formed was studied using RRKM theory.