The oxidation of cis ‐ and trans ‐CHClCHCl

When Cl atoms react with CHClCHCl in the presence of O 2 at 31°C, a long‐chain oxidation occurs. The products are the geometrical isomer of the starting olefin and CHClO, HCl, CO, and CCl 2 O. The quantum yields of the oxygen‐containing products are the same with both isomers and are Φ{CHClO} = 30, Φ{CO} = 11.7, and Φ{CCl 2 O} = 1.29. The chlorine atom adds to the olefin and is followed by O 2 addition. The reaction then proceedswith k 6a / k 6b = 19 and k 7a / k 7 ∼ 0.5, where k 7 ≡ k 7a + k 7b . The CCl 2 H radical oxidizes to regenerate the chain carrier. O( 3 P ) reacts with CHClCHCl at 25°C with a rate coefficient of 6.6 × 10 8 M −1 sec −1 for trans ‐CHClCHCl and 2.8 × 10 8 M −1 sec −1 for cis ‐CHClCHCl. The reaction channels arewith k 1a / k 1 = 0.23 and 0.28, respectively, for the cis and trans compounds. Reaction (1b) occurs < 4% of the time. Reaction (1c) leads to polymer production and presumably, via redissociation, to the geometrical isomer of the starting olefin. In the presence of O 2 the same long‐chain oxidation is observed as in the chlorine‐atom initiated oxidation. The chain‐initiating step is\documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm CHCl + O}_{\rm 2} \to {\rm HO + ClCO} \to {\rm Cl + CO} $$\end{document}