Dye-sensitized photooxygenation of diphenylamine in sodium dodecyle sulphate micellar solution

Abstract

A kinetic study of methylene blue (MB) sensitized photooxygenation of diphenylamine (DPA) in sodium dodecyl sulphate micellar solution has been shown to give N-phenyl-<i>p</i>-benzoquinoneimine (PBQ) as the only primary coloured product. The steady state rate expressions based on a likely mechanism have been derived. The data fit well into these equations showing both the singlet oxygen and electron transfer pathways, the relative efficiency of which depends upon the [DPA].The effect of varying dielectric and [O<sub >2</sub>] further supports the postulated mechanism. The deactivation of triplet MB by dimeric dye species (MB)<sub >2</sub> has been postulated at higher [MB].