Temperature and oxygen effect on oscillations of the Belousov-Zhabotinsky reaction with 2-oxopentanedioic acid as substrate

The temperature dependence of the influence of oxygen an the Belousov-Zhabo tinsky (BZ) system with a Ce(IV)-Ce(III) redox catalyst and 2-oxopentanedio ic acid as substrate and on the autocatalytic oxidation of Ce(III) ions wit h bromate was studied in detail. The influence of temperature on the induct ion period, the period of the second oscillation, duration and number of os tillations, and finally on the average frequency of oscillations, was inves tigated both in oxygen and in nitrogen. The corresponding activation parame ters have been determined and discussed. The most pregnant effect of oxygen is observed on the temperature dependence of the duration and the number o f oscillations. The value for enthalpy of activation is more than 50 kJ mol (-1) higher in oxygen than in nitrogen. The presence of oxygen may generate chaotic behaviour or multi-mode oscillations since in the presence of oxyg en, new intermediates in the BZ system are formed, thereby increasing its c omplexity.