Application of the tubular graphite electrode in the measurement of reaction kinetics: development of an automatic technique

Abstract

The unique feature of the tubular electrode, that it permits continuous analysis of an electrolyte solution passing through it, has been made use of in developing an automatic voltammetric technique for studying the kinetics of reactions involving one or more electro-active reactants or products. The technique provides for automatic dilution of the reaction mixture with the supporting electrolyte in order to bring the concentrations within the voltammetric range, automatic freezing of the reaction when required, automatic stirring of the reaction mixture solution and, especially, automatic recording of the current-time graph, from which the kinetics of the reactions can easily be studied.

The technique has been standardised by studying voltammetrically the reaction kinetics of the oxidation of potassium iodide with hydrogen peroxide in aqueous acidic solutions and comparing the data with those obtained titrimetrically. The results appear to show that the automatic technique has a high dependability. Encouraging results have been obtained in the study of the reaction kinetics of the oxidation of potassium hexacyanoferrate(II) with hydrogen peroxide and of sodium formate with potassium permanganate in acidic media.