School of Chemical Engineering, China University of Mining and Technology, Xuzhou 221116, P. R. China.
Phys Chem Chem Phys. 2023 May 10;25(18):13183-13188. doi: 10.1039/d3cp00011g.
Autocatalytic feedback is often regarded as the core step for the chemo-hydrodynamical patterns in the nonlinear reaction system. The Briggs-Rauscher (BR) reaction shows sequential chemo-hydrodynamical patterns with three states, labyrinth, high iodine state, and rotating dendritic patterns. The short-lived labyrinth patterns, depending on [Mn], the ratio of [CH(COOH)] and [KIO] and light intensities, result from iodide autocatalytic loop, which has three paths (involving Mn-induced radical reactions, the oxidation of iodomalonic compounds, and light-induced radical reactions, respectively). The high iodine state appears in a high ratio of [CH(COOH)] and [KIO], relating to the autocatalytic path involving the oxidation of iodomalonic compounds. The light-induced radical autocatalytic path can act as a convenient control parameter to modulate the patterns in the first stage by increasing the iodine radicals. The dendritic patterns in the third stage result from the Marangoni effect caused by the evaporation of the solutions and reactions between HO and iodine-containing species, which is independent of [CH(COOH)] and [Mn]. This work contributes to a better understanding of the complex spatiotemporal patterns in the chemo-hydrodynamical system.
自催化反馈通常被认为是非线性反应系统中化学-水力图案形成的核心步骤。Briggs-Rauscher（BR）反应表现出具有三个状态的顺序化学-水力图案，即迷宫状、高碘状态和旋转树突状图案。短暂的迷宫状图案取决于[Mn]、[CH(COOH)]和[KIO]的比例以及光强度，由碘化物自催化循环产生，该循环具有三条路径（分别涉及 Mn 诱导的自由基反应、碘代丙二酸化合物的氧化和光诱导的自由基反应）。高碘状态出现在[CH(COOH)]和[KIO]的高比例中，与涉及碘代丙二酸化合物氧化的自催化途径有关。光诱导自由基自催化途径可以作为一个方便的控制参数，通过增加碘自由基来调节第一阶段的图案。第三阶段的树突状图案是由溶液蒸发和 HO 与含碘物质之间的反应引起的 Marangoni 效应产生的，与[CH(COOH)]和[Mn]无关。这项工作有助于更好地理解化学-水力系统中复杂的时空图案。
