Alternative Kinetic Model of the Iodide–Iodate Reaction for Its Use in Micromixing Investigations
Arturo N. Manzano Martı́nez, A. Sander Haase, Melissa Assirelli, J. van der Schaaf
Abstract
The Villermaux–Dushman method,\none of the most extensively\nused test reaction systems for micromixing characterization, has been\nwidely criticized for years due to uncertainties regarding the incomplete\ndissociation of sulfuric acid and the proposed kinetic study by Guichardon\net al. In this work, a renewed study of the kinetics of the iodide–iodate\nreaction is presented, using perchloric acid to avoid issues concerning\nincomplete acid dissociation. The experimental results are in good\nagreement with the fifth-order rate law for the iodide–iodate\nreaction. The reaction rate coefficient strongly depends on the ionic\nstrength and can be modeled with a Davies-like equation. When implemented\nin the incorporation model, the kinetic model presented in this study\ncan be used to estimate micromixing times that are in line with the\ntheoretical engulfment time. This is observed in two different reactors\nwith low and high intensities of mixing: an unbaffled stirred vessel\nand a rotor–stator spinning disk reactor. The results from\nthe latter are also compared with the second Bourne reaction, giving\nvery similar micromixing times. The kinetic model presented in this\nstudy in combination with strong monoprotic acids is suggested as\nan alternative to characterize micromixing behavior.