ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Influence of oxygen on the Belousov—Zhabotinskii oscillating reaction. III. Release of bromides, kinetics of malonic acid oxidation by manganese(III), and simulating calculations

I. Tkáč and Ľ. Treindl

Department of Physical Chemistry, Faculty of Natural Sciences, Komenský University, CS-842 15 Bratislava

Abstract: Bromide ions are released by the effect of oxygen more rapidly in the reaction of the Mn³⁺ ions with a mixture of malonic acid (MA) and bromoma- lonic acid (BrMA) of low summary concentration, but the overall released quantity is smaller. At a high summary concentration of MA and BrMA the quantity of released Br^- ions in the presence of oxygen is substantially greater. To follow the concentration of the Br^- ions during oscillations the Polarogra­ phie method with Pt-electrode may be used. Oxygen enhances the rate of Mn³⁺ consumption in the reaction with MA of a low concentration, but reduces it at a high concentration of MA. In addition, the oxygen consumption increases with MA concentration. A new mechanism has been proposed for the influence of oxygen on the oxidation of MA by Mn³⁺ Its essence is an acceleration of Mn³⁺ consumption by the reaction with glyoxylic acid at low MA concentration  and regeneration of Mn³⁺ by oxidation of Mn²⁺ with hydroperoxide (MAOOH) at high MA concentration.

Full paper in Portable Document Format: 392a175.pdf

Chemical Papers 39 (2) 175–190 (1985)