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Paper - Experimental and Modeling Study of Oscillations in the Chlorine Dioxide Iodine Malonic-Acid Reaction

2016-03-01 posted in [Paper]

Lengyel, I., Rabai, G. & Epstein, I. R. Systematic Design of Chemical Oscillators .67. Experimental and Modeling Study of Oscillations in the Chlorine Dioxide Iodine Malonic-Acid Reaction. J Am Chem Soc 112, 9104-9110, doi:DOI 10.1021/ja00181a011 (1990)

At pH 0.5-5.0, a closed system containing an aqueous mixture of chlorine dioxide, iodine, and a species such as malonic acid (MA) or cthyl acetoacetate, which reacts with iodine to produce iodide, shows periodic changes in the light absorbance of I;. This behavior can be modeled by a simple scheme consisting of three component reactions: ( I ) the reaction between MA and iodine, which serves as a continuous source of I-; (2) the reaction between ClO,’ and I-, which acts as a source of C102-: and (3) the self-inhibited reaction of chlorite and iodide that kinetically regulates the system. The fast component reaction bctwccn chlorinc dioxide and iodide ion was studied by stopped-flow spectrophotometry. The rate law is -[C102’]/df = 6 X IO3 ( M-2s -‘)[CIO,’][I-]A. two-variable model obtained from the empirical rate laws of the three component reactions givcs a good dcscription of the dynamics of the system. The oscillatory behavior results not from autocatalysis but from the self-inhibitory character of the chlorite-iodide reaction.

http://pubs.acs.org/doi/abs/10.1021/ja00181a011