Abstract
Large amplitude pH oscillation occurs in the iodate oxidation of hydroxylamine in a continuous-flow stirred tank reactor(CSTR) in a narrow range of flow rate sand in put concentrations.In addition to pH,the redoxpotential,the iodide ion concentration,the rate of gas(N20)formation,and the color of the solution(I2) change periodically.The oscillatory period is extremely long,2-6h.The dynamical behavior of the reaction was modeled by a scheme that takes into account the following component processes:the protonation equilibrium of NH2OH, the dissociation of water,the directed redox reaction between103'andNH3OH+,the Dushman reaction betweenI03"and ,the auto inhibitory reaction between I2andNH3OH+,the fast dimerization of NOHtoN20,there action of NOH with NH2OH,and the volatility of iodine.Empirical rate laws of the component reactions were used successfully to calculate the kinetic behavior in a closed system,as well as in the CSTR.