Chlorine dioxide-induced and Congo red-inhibited Marangoni effect on the chlorite-trithionate reaction front.

Hydrodynamic flows can exert multiple effects on an exothermal autocatalytic reaction, such as buoyancy and the Marangoni convection, which can change the structure and velocity of chemical waves. Here we report that in the chlorite-trithionate reaction, the production and consumption of chlorine dioxide can induce and inhibit Marangoni flow, respectively, leading to different chemo-hydrodynamic patterns. The horizontal propagation of a reaction-diffusion-convection front was investigated with the upper surface open to the air.

pH oscillations and mechanistic analysis in the hydrogen peroxide-sulfite-thiourea reaction system.

A new pH oscillator has been constructed by combining the pH clock reaction H2O2-SO3(2-)-H(+) with thiourea (Tu, (NH2)2CS) as a proton-consuming species. The system exhibited oligo-oscillatory behavior in a closed system, and large amplitude oscillations in a continuous-flow stirred tank reactor (CSTR) were observed in a narrow range of input concentrations, flow rate, and temperature. For the purpose of constructing the kinetic model, a reversed-phase ion-pair high-performance liquid chromatography (HPLC) and mass spectrometer (MS) were used to track and determine intermediate species during the oxidation of thiourea by hydrogen peroxide.

Pattern formation in the iodate-sulfite-thiosulfate reaction-diffusion system.

Sodium polyacrylate-induced pH pattern formation and starch-induced iodine pattern formation were investigated in the iodate-sulfite-thiosulfate (IST) reaction in a one-side fed disc gel reactor (OSFR). As binding agents of the autocatalyst of hydrogen ions or iodide ions, different content of sodium polyacrylate or starch has induced various types of pattern formation. We observed pH pulses, striped patterns, mixed spots and stripes, and hexagonal spots upon increasing the content of sodium polyacrylate and observed iodine pulses, branched patterns, and labyrinthine patterns upon increasing the starch content in the system.

Investigations of different chemiluminescent peaks in H2O2-SCN(-)-Cu(2+)-OH(-)-luminol flow system.

In the H2O2-SCN(-) -Cu(2+)-OH(-)-luminol oscillatory system of chemiluminescence, the effects of the ingredient concentrations, temperature, flow rate and complexing agent on the oscillatory dynamics were investigated in a continuous-flow stirred tank reactor (CSTR). The dynamical structure of two peaks during a period was discussed in detail. By addition of EDTA to the oscillating system, the peak I height decreased sharply while the peak II height was little affected, and the period kept constant.

Oscillations and mechanistic analysis of the chlorite-sulfide reaction in a continuous-flow stirred tank reactor.

Sustained oscillations in pH and redox potential are found in the chlorite-sulfide reaction in a continuous-flow stirred tank reactor (CSTR). Autocatalytic oxidation of HSO(3)(-) by ClO(2)(-) is the major source of positive feedback of hydrogen ions. The reaction between H(2)S and ClO(2)(-) to form S(8), which consumes H(+), is an important source of negative feedback.