A pulse radiolysis study of oil/water microemulsions

Absorption spectrum and the yield of e_aq⁻ determined in quaternary benzene/water and dodecane/water microemulsions were found to be identical with those in pure water. This indicates that the excess electrons produced in the oil droplets cross the oil/water interface and appear in the aqueous phase as hydrated electrons. On the contrary, it was found that the OH radical yield measured by converting into (SCN)₂^.− was directly proportional to the water content and there was no contribution from the oil phase. The e_aq⁻ decay in aerated microemulsion showed that the [O₂] in the aqueous phase was decreasing with continuous pulse irradiation and the estimated G(–O₂) in the oil was higher than in water. However, peroxides were predominantly formed in the aqueous phase and almost not in the oil. Rate constants for the addition of e_aq⁻ and OH to benzene in the benzene/water microemulsion and the following bimolecular decay of cyclohexadienyl and hydroxycyclohexadienyl radicals agree well with those reported in aqueous solutions.