Reactions of oxygenated radicals in the gas phase. Part 9.—Self-reactions of isopropylperoxy radicals

Abstract

The principal products of the photo-oxidation of trans-2,2′-azopropane between 333 and 373 K are acetone, isopropyl alcohol, isopropyl hydroperoxide, acetaldehyde, formaldehyde, methyl alcohol and cis-2,2′-azopropane. The reaction mechanism has been simulated in detail, and, in conjunction with results obtained earlier for the overall self-reaction of isopropylperoxy radicals, the following rate data have been obtained for the reactions 2(CH₃)₂CHO₂·→(CH₃)₂CHOH +(CH₃)₂CO + O₂(3a), 2(CH₃)₂CHO₂·→ 2(CH₃)₂CHO·+ O₂(3b)k_3b/k_3a increases with temperature, from 1.39 ± 0.04 at 302 K to 1.83 ± 0.04 at 333 K and 2.80 ± 0.08 at 373 K. Values of A_3a and A_3b of 2.44 ± 0.31 × 10⁷ and 1.38 ± 0.26 × 10⁹ dm³ mol^–1 s^–1 and E_3a and E_3b of 12.0 ± 1.0 and 21.3 ± 1.5 kJ mol^–1 were determined.