INHIBITING AND CHEMILUMINESCENT PROPERTIES OF BENZOIC-ACID AND ACETYLSALICYLIC-ACID IN THE FENTON REAGENT SYSTEM

Benzoic acid and acetylsalicylic acid were found to perform well as in hibitors of the radical-chain decomposition of hydrogen peroxide catal yzed with iron ions in an aqueous solution. The inhibition process was found to be accompanied by chemiluminescence. Using light filters, th e radiation region was estimated (> 470 nm; lambda(max) approximate to 530 nm). Chemiluminescence was found to become more intense in the pr esence of oxygen. The inhibition effect was accounted for by the decay of HO. and HO2. radicals, which are generated by the decomposition of hydrogen peroxide on Fe2+ and Fe3+ ions. The mechanisms of radical de cay were suggested to be the coordination of these radicals by metal i ons mediated by molecular oxygen and the quadratic recombination on a double bond of the inhibitor. The formation of a singlet oxygen is hyp othesized in this region. This dinner is suggested to be responsible f or the chemiluminescence observed.