A NEW BROMITE OSCILLATOR - LARGE-AMPLITUDE PH OSCILLATIONS IN THE BROMITE-THIOSULFATE-PHENOL FLOW SYSTEM

The reaction between bromite and thiosulfate ions in aqueous solution with and without phenol has been studied under batch and now condition s. The bromite oxidation of thiosulfate proceeds via two consecutive f ast reactions, the first accompanied by a significant increase, the se cond by a large decrease in pH. The H+ production is autocatalytic and strongly influenced by phenol. The bromite-thiosulfate-phenol flow sy stem exhibits bistability and large-amplitude pH oscillations. Several relevant reactions such as bromite-phenol, bromite-bromide, bromate-t hiosulfate, and bromate-phenol were also investigated, and their parti cipation in the batch and flow behavior of the bromite-thiosulfate-phe nol system is discussed. A qualitative explanation of the pH oscillati on is proposed.