Electric field effects on selectivity of reactions within propagating reaction fronts

A series of experimental observations of the effects of applying electric f ields to propagating reaction fronts in the iodate-arsenous acid system are presented. These demonstrate that changes in the local concentrations of r eaction components due to ionic migration result in profound changes of sel ectivity of reactions within the front reflected in variations of front con centration profiles and velocities of propagation. The controlled switching on/off of the electric held leads to the formation of a variety of complex spatio-temporal concentration patterns. Results are obtained from a mathem atical model having the generic features of the basic kinetic mechanism. Th ese agree with the experimental observations and provide an explanation for variations in,reaction selectivity. (C) 1999 Elsevier Science Ltd. All rig hts reserved.