Complex spatiotemporal behavior in the photosensitive ferroin-bromate-4-nitrophenol reaction

Investigation illustrates that the bromate-4-nitrophenol reaction in a stirred batch reactor undergoes spontaneous oscillations under very broad initial reactant concentrations. The addition of ferroin has subtle influences on the nonlinear behavior, in which the frequency and total number of oscillations were greatly reduced at a low or high ferroin concentration, as opposed to the significant increase at a moderate ferroin concentration. Temporal oscillations with a modulating frequency were also observed in the ferroin-bromate-4-nitrophenol system. In a capillary tube the ferroin-bromate-4-nitrophenol reaction generated propagating wave trains with various complex behaviors such as period-doubled intermittent propagation failure. Illumination was found to have a profound effect on the temporal oscillations in the bromate-4-nitrophenol reaction and on those long lasting wave activities. Spectroscopic studies were able to identify 1,4-benzoquinone, 2-bromo-1,4-benzoquinone, and 2-bromo-4-nitrophenol as major components during the reaction.