Methylene blue sensitized oxidation of ethylene thiourea in cationic micellar medium

Ethylene thiourea (ETU) is relatively stable to hydrolysis but can be rapidly photolysed in the presence of photosensitizers. An aqueous solution of 8.0 × 10−4 M ETU and 5.0 × 10−5 M methylene blue (MB) was photolysed for 90 min with halogen lamp both in the presence and absence of cetyltrimethyl ammonium bromide (CTAB). 2-Imidazoline-2-yl-sulphinic acid (ISH) has been identified as the primary product both in the homogeneous and micellar media by chromatographic spectral analysis. The effects of various kinetic parameters were studied to lay down the mechanistic details of the reaction. On the basis of the kinetic studies the participation of singlet oxygen at low ETU concentration is postulated. However, ionic mechanism is suggested at high ETU concentration.