scholarly journals Chlorine Dioxide-Iodide-Methyl Acetoacetate Oscillation Reaction Investigated by UV-Vis and Online FTIR Spectrophotometric Method

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
Laishun Shi ◽  
Xiaomei Wang ◽  
Na Li ◽  
Jie Liu ◽  
Chunying Yan
Keyword(s):  
Induction Period ◽  
Chlorine Dioxide ◽  
Spectrophotometric Method ◽  
Ph Value ◽  
Great Influence ◽  
Reaction System ◽  
Oscillatory Behavior ◽  
Methyl Acetoacetate ◽  
Oscillation Reaction ◽  
Online Ftir

In order to study the chemical oscillatory behavior and mechanism of a new chlorine dioxide-iodide ion-methyl acetoacetate reaction system, a series of experiments were done by using UV-Vis and online FTIR spectrophotometric method. The initial concentrations of methyl acetoacetate, chlorine dioxide, potassium iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at wavelength of 289 nm. There is a preoscillatory or induction period, and the amplitude and the number of oscillations are associated with the initial concentration of reactants. The equations for the triiodide ion reaction rate changing with reaction time and the initial concentrations in the oscillation stage were obtained. Oscillation reaction can be accelerated by increasing temperature. The apparent activation energies in terms of the induction period and the oscillation period were 26.02 KJ/mol and 17.65 KJ/mol, respectively. The intermediates were detected by the online FTIR analysis. Based upon the experimental data in this work and in the literature, a plausible reaction mechanism was proposed for the oscillation reaction.

Modeling study for oscillatory reaction of chlorite – iodide – ethyl acetoacetate

2014 ◽  
Vol 92 (5) ◽  
pp. 417-425 ◽  
Author(s):  
Laishun Shi ◽  
Jian Gao ◽  
Jingjing Chen
Keyword(s):  
Chlorine Dioxide ◽  
Ethyl Acetoacetate ◽  
Ph Value ◽  
Great Influence ◽  
Iodine Concentration ◽  
Hydrogen Ion ◽  
Initial Concentration ◽  
Bifurcation Surface ◽  
Concentration Changes ◽  
Theoretical Evidence

Chlorine dioxide based chemical oscillating behavior was modeled by a simple scheme consisting of three component reactions. Furthermore, little is known about the influence of the pH value. In this study, four component reactions were used to model the chlorite – iodide – ethyl acetoacetate oscillating reaction by dynamic analysis software. The oscillatory phenomenon is observed for concentration changes of triiodide ion, chlorite ion, and hydrogen ion. The initial concentration of ethyl acetoacetate, chlorite ion, iodide ion, and hydrogen ion has great influence on oscillations. The amplitude and number of oscillations are associated with the initial reactant concentrations. The equation of the reaction rate of triiodide ion, chlorite ion, or hydrogen ion changing with reaction time and initial concentrations in the oscillation stage was obtained. The bifurcation surface between oscillatory and nonoscillatory behavior with different pH values was obtained. The spatial zone for the occurrence of oscillation is reduced with an increase in the pH value. The range of oscillation as concentrations of chlorine dioxide, iodine, and ethyl acetoacetate is well described by an equation. There is a lower limit on ethyl acetoacetate initial concentration for oscillation. However, there is a higher limit on chlorine dioxide and iodine concentration for oscillation. The concentrations of chlorine dioxide and iodine for oscillation decrease with an increase in the pH value. The results provide new theoretical evidence of the importance of pH value, which can affect the bifurcation surface between oscillatory and nonoscillatory behavior.

Sodium chlorite – iodide – acetylacetone oscillation reaction investigated by UV-Vis spectrophotometry

2015 ◽  
Vol 93 (10) ◽  
pp. 1069-1075
Author(s):  
Jingjing Chen ◽  
Laishun Shi ◽  
Demei Li ◽  
Ying Wang ◽  
Shujie Lin ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Ph Value ◽  
Great Influence ◽  
Sodium Chlorite ◽  
Similar Reaction ◽  
Initial Concentration ◽  
Oscillation Reaction ◽  
Apparent Activation Energies ◽  
Two Stages ◽  
Induction Stage

A new sodium chlorite – iodide – acetylacetone chemical oscillatory reaction has been studied by the UV-Vis spectrophotometric method. The initial concentrations of acetylacetone, sodium chlorite, iodide, and sulfuric acid and the pH value have great influence on the oscillation observed at a wavelength of 570 nm for the starch–triiodide complex. There is a pre-oscillatory or induction stage and the amplitude and number of oscillations depend on the initial concentration of the reactants. Equations for the starch–triiodide complex reaction rate change with reaction time and the initial concentrations in the oscillation stage were obtained. The induction time decreases linearly with the initial concentration of acetylacetone or sodium chlorite but increases linearly with the initial concentration of sulfuric acid. The oscillation reaction can be accelerated by increasing the reaction temperature. The apparent activation energies at the induction stage and the oscillation stage were 61.02 and 61.36 kJ/mol, respectively, indicating that the two stages have similar reaction mechanisms. Generating the enol isomer by keto–enol tautomerism is an important step to constrain the time of the induction period.

scholarly journals Experimental Study of Closed System in the Chlorine Dioxide-Iodide-Sulfuric Acid Reaction by UV-Vis Spectrophotometric Method

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Na Li ◽  
Laishun Shi ◽  
Xiaomei Wang ◽  
Fang Guo ◽  
Chunying Yan
Keyword(s):  
Reaction Time ◽  
Chlorine Dioxide ◽  
Transition Point ◽  
Great Influence ◽  
Reaction System ◽  
Buffer Solution ◽  
Acid Reaction ◽  
Ph Buffer Solution ◽  
Ph Buffer ◽  
Closed Reaction System

The mole ratior(r=[I−]0/[ClO2]0)has great influence on ClO2-I−-H2SO4closed reaction system. By changing the initiate concentration of potassium iodide, the curve of absorbance along with the reaction time was obtained at 350 nm and 297 nm for triiodide ion, and 460 nm for iodine. The changing point of the absorbance curve's shape locates atr=6.00. For the reaction of ClO2-I−in the absence of H2SO4, the curve of absorbance along with the reaction time can be obtained at 350 nm for triiodide ion, 460 nm for iodine. The mole ratioris equal to 1.00 is the changing point of the curve's shape no matter at which wavelength to determine the reaction. For the reaction of ClO2-I−-H+in different pH buffer solution, the curve of absorbance along with the reaction time was recorded at 460 nm for iodine. Whenris greater than 1.00, the transition point of the curve's shape locates at pH 2.0, which is also the point of producing chlorite or chloride for chlorine dioxide at different pH. Whenris less than 1.00, the transition point locates at pH 7.0.

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