Chemical Oscillations With Sodium Perborate as Oxidant.

The peroxo compounds HO and KSO represent one of the major constituents in many oscillatory chemical systems. In this contribution we demonstrate that beside HO and S the sodium perborate (NaBO·HO) can act as alternative oxidizing agent in oscillatory reactions. So far the HO has been successfully substituted with NaBO in two oscillators: in the BO -S -Cu(II) flow system potential and pH oscillations, in the strongly alkaline Cu(II)-catalyzed BO -SCN batch reaction, which are rather different in their chemistry and dynamics, potential oscillations were observed. In spite of the significant differences in the oxidizing nature of HO and NaBO we assume that the oscillatory cycle in the BO -substrate and in the HO-substrate systems is similar in many aspects, therefore the numbers of this new subgroup of the oscillators may be considered to be borate-mediated HO oscillators. Mechanisms are suggested and simulations are shown to describe the oscillatory behaviors observed in the perborate chemistry based oscillators by using the assumption that the oxidation reactions of the intermediates (HO)B(OOH) and (HO)B(OOH) anions, which are dominant species in alkaline and neutral pH solutions of perborate, are much faster than that of HO.