A pulse radiolysis study of oil/water microemulsions

Absorption spectrum and the yield of e(aq)(-) determined in quaternary benz ene/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 ph ase as hydrated electrons. On the contrary. it was found that the OH radica l yield measured by converting into (SCN)(2)(-) was directly proportional t o the water content and there was no contribution from the oil phase. The e (aq)(-) decay in aerated microemulsion showed that the [O-2] in the aqueous phase was decreasing with continuous pulse irradiation and the estimated G (-O-2) in the oil was higher than in water. However, peroxides were predomi nantly formed in the aqueous phase and almost not in the oil. Rate constant s for the addition of e(aq)(-) and OH to benzene in the benzene/water micro emulsion and the following bimolecular decay of cyclohexadienyl and hydroxy cyclohexadienyl radicals agree well with those reported in aqueous solution s. (C) 2001 Elsevier Science Ltd. All rights reserved.