Recombination of tertiary butyl peroxy radicals. Part 1.—Product yields between 298 and 373 K

Abstract

Overall product distributions resulting from the recombination of t-butyl peroxy radicals have been studied over the temperature range 298–373 K. The results indicate that over this range there is a switch from the terminating channels (forming alcohol and aldehyde/ketone) towards non-terminating channels (forming two alkoxy radicals) for the two further recombination processes that follow the initial combination of t-butyl peroxy radicals: CH₃O₂˙+ t-BuO₂˙→ products, 2CH₃O₂˙→ products.

There is also direct evidence for the presence of a terminating channel to form di-t-butyl peroxide. This reaction proceeds at a rate of ca. 0.14 of the non-terminating recombination rate at 298 K, but this fraction falls to 0.025 at 333 K and the reaction is not evident at 373 K.

Our results demonstrate the importance of abstraction reactions involving alkoxy radicals (t-butoxy and methoxy) and one of the principal recombination products, t-butyl hydroperoxide. Rate constant ratios involving these processes have been derived from the product distributions and from additional studies in which t-butyl hydroperoxide was added. Rate constants of ca. 10^–13 cm³ molecule^–1 s^–1 for these abstraction processes are consistent with our results.