Eur. Phys. J. Special Topics 227, 509–520 (2018)
https://doi.org/10.1140/epjst/e2018-00075-y

Regular Article

Acceleration of chemical reaction fronts

II. Gas-phase-diffusion limited frontal dynamics

¹ Institut für Physik, Otto-von-Guericke Universität Magdeburg, Universitätsplatz 2, 39106 Magdeburg, Germany
² Hyogo University of Teacher Education, Shimokume 942-1, Kato City, Hyogo 673-1494, Japan
³ Institut für Biometrie und Medizinische Informatik, Otto-von-Guericke Universität Magdeburg, Leipziger Straße 44, 39120 Magdeburg, Germany
⁴ Department of Mathematical and Life Sciences, Hiroshima University, Higashi-Hiroshima 739-8526, Japan

^a e-mail: marcus.hauser@ovgu.de

Received: 16 August 2017
Received in final form: 6 February 2018
Published online: 4 October 2018

Abstract

The propagation of reaction-diffusion fronts in an open liquid solution layer is critically affected by mass transfer between the liquid solution and the adjacent gas phase. This is the case in the iodate–arsenous acid (IAA) reaction when run under stoichiometric excess of iodate. Here, iodine is the reaction product, which has a low solubility in the liquid phase, hence, excess iodine rapidly evaporates. In the gas phase, it diffuses and overtakes the reaction front propagating in the liquid medium because its diffusion coefficient in the gas phase is considerably larger than that in aqueous solution. Evaporated iodine is re-dissolved into the reaction medium ahead of the reaction front. Since iodine is the autocatalytic species of the IAA reaction, this additional gas-phase transport may lead to an acceleration of the propagating reaction front.