Enthalpies of formation of the benzyloxyl, benzylperoxyl, hydroxyphenyl radicals and related species on the potential energy surface for the reaction of toluene with the hydroxyl radical

Abstract

The reaction of toluene (T) with OH • produces addition products as well as the benzyl radical (TR). TR can react with OH • or O2 to produce oxygenated species, for many of which there is no experimental information available. We present here theoretically determined heats of formation (HFs) of 17 such species using the non-isodesmic reactions on the potential energy surface (PES) of TR+O2 and T+OH • +O2. For those species the experimental HFs of which are known, we obtained a good correlation between experimental and theoretical values at the G4 (r 2 =0.999) and M06/cc-pVQZ (r 2 =0.997) levels, thus showing the goodness of the methods used. Previously unknown HFs of other radicals (benzyloxyl, spiro [1,2-dioxetane benzyl], hydroxyphenyl, and benzylperoxyl) and closed shell species (salicylic alcohol, benzo[b]oxetane and p-hydroxy cyclohexa-2,5dienone) were later determined using those methods.