The tube electrode and e.s.r.: Second order kinetics

A radical species is generated on a tube electrode; it is then transported under conditions of laminar flow through an e.s.r. cavity. In the bulk of solution it decomposes by second order kinetics. The convective diffusion equation for this problem is treated by the simulation method. This method is greatly improved if the spatial co-ordinates are suitably distorted. The distortion used in this work is applicable to all problems involving tube and channel electrodes. The results of the calculation are tested using the reduction of nitrobenzene and are found to be in good agreement with experiment. An upper limit is estimated for the second order rate constant for the radical decomposition above which the radicals will not be detected.