The reaction between chlorite and thiourea could display batch oligooscillation and CSTR oscillation of pH.Batch pH peak has the same character with pH oscillation in a CSTR.The oxidation of thiourea produced intermediates such as HOSC(NH)NH2,HO2SC(NH)NH2,HO3S(NH)NH2 and bisulfite.The valence change of sulfur has close relation with pH dynamics.Through the mechanistic analysis,a general model of sulfur(－ II) oxidation,which consists of negative hydrogen ion feedback(S(－ II) to S(0)),a transition process of S(0) to S(IV) and positive proton feedback from S(IV) to S(VI),could simulate batch oligooscillation and CSTR oscillation.This result is setting up a new channel to uncover the reaction mechanism and simulate the nonlinear phenomena in the reactions between chlorite and Sulfur(－ II).
The general dynamic features of the batch oxidation of Sulfur(-Ⅱ) compounds (S2-,thiosuifae, thiocynate and thiourea et al. ) were discussed. The changes of pH with reaction time consist of a rise and two separate drops. Dynamic model was proposed, further experimental studies on the batch oxidation of thiourea and thiocyanate by ClO2- were also canied out. Simulation curve was well consistent with experiment in a batch reactor.Non-catalytic oscillation of peroxide (hydrogen peroxide, persulfate et al. ) - S(-Ⅱ)-compound system resulted from the nonlinear dynamic of sulfur oxidation. In the oxidation of S(-Ⅱ)-compounds by oxyhalogen compounds(ClO2 - et al. ), nonlinear dynamics of both oxyhalogen compound and suifur compound should be considered simultaneously. So complex phenomena such as birhythmicity and chaos may be discovered.
