THE PHOTOSENCITIZED REACTION AND MECHANISM OF 8-HYDROXY QUINOLINE-5-SULPHONIC ACID USING METHYLENE BLUE (MB) AS PHOTOSENSITIZER

The photosensitized reaction of 8-hydroxyquinoline 5-sulphonic acid has been studied in the alkaline medium in the visible light using Methylene blue (MB) as photosensitizer. The rate of the reaction has been calculated. The effect of the parameters like pH, concentration of the sensitizer, concentration of the substrate, and intensity of the light on the rate of the photosensitized reaction has been studied. The reaction has been studied in anaerobic condition to observe the effect of the oxygen. Methanol shows free radical scavenging effect. The quantum efficiency of the photosensitized reaction has been calculated. The scheme of the reaction mechanism is suggested. The singlet state of the oxygen ( 1 O2) participates in the photoreaction and photooxidation products are formed by oxidation of the substrates. The reaction has been studied using UV-visible spectroscopy and product analyzed with Mass-spectrometry.