The Theoretical Analyses And Mathematical Simulation Of Some Nonlinear Chemical Reactions

Part 1.Progress of the nonlinear chemical phenomena and mathematical simulation(Review)A brief review about nonlinear chemical phenomena is made in the following aspects:the concepts of chemical oscillating reaction,chaos,chemical wave,the oscillating of liquid membrane and macroscopic self-motion on the oil/water interface, the research history and the application to analytical chemistry.The advances of these phenomena,the methods and the mathematical simulation were also reviewed in detail.Part 2.Computational simulation of Belousov-Zhabotinskli(BZ)oscillating chemical reactionThe suitability of computational simulation of the Belousov-Zhabotinskii(BZ) oscillating chemical reaction by differential kinetic methodology for resolving nonlinear multi-component system is demonstrated in this work.According to the Field-Koros -Noyes(FKN)mechanism and the Oregonator model,the change of the concentrations of HBrO₂,bromide ion and cerium ion are simulated.The results of computational simulation are consistent with experimental results very well.At the same time,the effect of variables and parameters,especially the rate constant on the oscillation curve,are also investigated deeply.A simple method of estimating rate constants is developed through simulating the concentrations of key components,and then comparing the simulation results with the experimental ones.The reasonable rate constant is also proposed.This method of determination of rate constants is simple and fast.Part 3.Nonlinear behavior in Bray-Liebhafsky chemical reactionThe Bray-Liebhafsky reaction exhibits different nonlinear behaviors during the iodate catalyis decomposition of acidic hydrogen peroxide in the different conditions. Both the chaotic and regular oscillations are observed.The largest Lyapunov exponent (λ_L),the power spectrum and the log(P)-log(f)dependence for power spectrum are used to evaluate these nonlinear behaviors.The effect of initial concentration of reactants on the types of oscillations and the initial potential(E_o)are discussed in detail.The possible mechanism of the Bray-Liebhafsky reaction is also approached.Part 4.Computational simulation of Bray-Liebhafsky(BL)oscillating chemical reaction.The computational simulation of the Bray-Liebhafsky(BL)oscillating chemical reaction by differential kinetic methodology is carried out in this work.According to the mechanism of Treindl and Noyes involving 10 reaction steps,the change of the concentrations of I₂ and O₂ are simulated.When the controlled parametersα=0.55,β0=0.2882 andδ＜0.6,the differential equations exists periodic solution,and the oscillation can be observed in 150 min.Ifα,βandδwere taken as the control parameter respectively,the bifurcations would be observed in the process with the critical values ofα=0.55,β=0.2882,andδ=0.6.The acidity of the solution on the nonlinear phenomena is investigated in detail.Part 5.Macroscopic self-motion of oil/water interface involving surfactant moleculesVarious types of macroscopic self-motion were observed on the interface between two phases,where the aqueous phase contained a surfactant cetylpyridinium bromide (CPB)and organic phase is a nitrobenzene solution of tetraethylammonium bromide (TEAB)and ethanol.When the two phases contract with each other,the interface exhibited three types motions:1)rotational motion,in clockwise and anticlockwise, and the interface motion switched between the two types;2)teeterboard motion,3) random motion.The motion can maintain about 30-120 min.The period and the duration of the motion depended on the concentrations of the components in the system.The mechanism of macroscopic motion was discussed by means of two aspects:chemical reaction and hydrodynamic.