H NMR Monitoring of Water Behavior during the Bray−Liebhafsky Oscillatory Reaction

Abstract

Proton NMR spectroscopy was used to monitor behavior of water during the oscillatiory part of the Bray−Liebhafsky (BL) reaction. A series of 1H NMR spectra showed the complex structure of the water signal with periodic changes of the chemical shift and line splitting, which were in agreement with the periodicity of the BL reaction obtained by potentiometric measurements. An analysis of known intermediates in the BL reaction indicated that oxygen formation both as dissolved and in form of bubbles has the dominant effect on NMR spectra. In addition, certain restructuring of water was observed during oscillations, suggesting the subtle role of water in the mechanism of the BL reaction and pointing out to the importance of the NMR techniques in investigation of the chemical oscillators.