ELECTROCHEMICAL GENERATION OF SOLUTION LUMINESCENCE—II: LUMINOL AND PHTHALHYDRAZIDE

Abstract

Abstract— The electrochemical techniques of voltage‐scan, chronopotentiometry, chrono‐amperometry, coulometry and square‐wave pulse have been applied to the electro‐oxidation of luminol and phthalhydrazide in an attempt to elucidate the mechanism and species responsible for electroluminescence in the presence of oxygen and base. The rate of electro‐oxidation has been shown to be diffusion controlled with no evidence of a reverse reduction wave. Monitoring of light intensity decays after a potential‐pulse has given a first order rate of 1.63 times 10 3 sec ‐1 at 25“. A heat of activation of 2.89 + 0.12 kcal/mole was determined for the reaction from the temperature dependence of the rate. A general reaction sequence for the electroluminescent pathway is proposed.