Modeling of Interactions Between Iodine Interphase Transport and Oxygen Production in the Modified Briggs−Rauscher Reaction with Acetone

Abstract

Novel aspects of influence of gas evolution on oscillating chemical reaction are considered on a model of the modified Briggs-Rauscher reaction with acetone. The mechanism proposed by Noyes with Furrow and De Kepper with Epstein, adapted for acetone and expanded with oxygen evolution and first-order escape of iodine by interphase transport, was subjected to further extension, and calculations assuming direct proportionality of the rate of iodine escape on the surface area of the oxygen gas trapped in the solution as well as calculations considering first-order back-flow of iodine from the gas phase into the solution were performed. Furthermore, the concentrations of iodine vapors were considered to be variable within the bubble population, as all the bubbles are not in contact with the reaction mixture for the same length of time. Distribution functions of the surface size over the range of concentrations of iodine in the contacting gas phase were introduced and derived, and whereas they were proved not to play any role in the total intensity of iodine return when it is first-order, the article also demonstrates their explicit consideration in calculations to be essential if the dependence of the rate of iodine return into the solution on its concentration is not linear, for example, in future extensions of the model with bubble radius also considered variable.

A Modified Recipe and Variations for the Briggs–Rauscher Oscillating Reaction

“…Attempts have been made to revise the skeleton mechanism, − but to date many unresolved questions remain. Reaction is probably not the source of radicals.…”

HOI versus HOIO Selectivity of a Molten-type AgI Electrode

“…Molecular iodine is also formed by oxidation of iodide or reduction of iodate, and the hydrolysis of iodine produces hypoiodous acid (I 2 + H 2 O ⇆ HOI + I – + H + ), which in turn is an important intermediate in the formation of iodine organic compounds and has a particularly important role in the exchange of iodine between seawaters and the atmosphere. − HOI is also a component of the waste streams from nuclear reactors . On the other hand, hypoiodous acid is a crucial intermediate in complex systems like the Bray–Liebhafsky (BL) − and Briggs–Rauscher (BR) − oscillating reactions. Kinetic studies and modeling of all these systems would benefit greatly from a sensitive device measuring the concentrations of HOI.…”

Are Uncatalyzed Bromate Oscillators Truly Gas-Free?

“…We have recently demonstrated, that the role of varying amounts of gaseous products in oscillating reactions should not be underestimated. 49 We also have good experience in highly precise closed-system real-time measurements of gases by simply weighing of liquid they displace, 48 and we were convinced, that this method could be improved, so that even very small amounts of gases would be measurable precisely. Therefore, we decided to undertake the task of applying the method in quantifying gas evolution from some examples of UBOs, hoping to contribute to verifying their reputation as gas-free oscillators.…”