Effects of pressure on the photoreduction of p-benzoquinone in normal and reversed micellar systems

The photoreduction of p-benzoquinone (p-BQ) in normal and reversed micellar systems has been studied kinetically under high pressures up to 150 MPa. Anionic sodium dodecyl sulphate (SDS) micelles accelerated the reaction, while cationic hexadecyltrimethylammonium bromide (CTAB) micelles retarded it. Pressure promoted the photoreaction in CTAB micellar systems, but not in SDS micelles. The reaction in Aerosol-OT reversed micellar systems (AOT/H2O/n-heptane) was faster than that in its bulk solvent, n-heptane. Micellar effects were found; however, these occurred at almost the same rates as that in water. The location of p-BQ in the micellar systems was studied using data for their critical micelle concentrations. The mechanisms of the reaction are also discussed.