Effect of Molecular Assemblage of Surfactants on Photooxygenation of Imidazolin-2-Ones

Imidazolin-2-ones (1) when subjected to dye sensitized photooxygenation in the presence of various solvents like chloroform, benzene, methanol, water either done or in mixture of any two as well as at different pH's (4.4, 7.0 and 9.2) yielded diacylureas as the major reaction products. The reaction was carried out in the presence of cationic (hexadecyltrimethyl ammonium bromide, CTAB); anionic (sodium dodecyl sulphate, SDS) and neutral (ethoxylated nonylphenol, ES) surfactants in aqueous methanol to explore the nature of intermediates. It was obseeved that CTAB enhances the yield of the product while SDS and ES exhibit no effect. The yield of the product was found to be maximum at 2 × 10^-3 M concentration of CTAB. A plausible mechanism of photooxygenation of imidazolin-2-ones involving zwitterionic perepoxides as a prelude to dioxetane formation has been suggested on the basis of observed surfactant, salt and solvent effects.