Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density‐Driven Pattern Formation
Year: 2009
Type: article
Abstract: Imperfect mixing is a concern in industrial processes, everyday processes (mixing paint, bread machines), and in understanding salt water‐fresh water mixing in ecosystems. The effects of imperfect mixing become evident in the unstirred ferroin‐catalyzed Belousov‐Zhabotinsky reaction, the prototype for chemical pattern formation. Over time, waves of oxidation (high ferriin concentration, blue) propagate into a background of low ferriin concentration (red); their structure reflects in part the history of mixing in the reaction vessel. However, it may be difficult to separate mixing effects from reaction effects. We describe a simpler model system for visualizing density‐driven pattern formation in an essentially unmixed chemical system: the reaction of pale yellow Fe3+ with colorless SCN− to form the blood‐red Fe(SCN) 2+ complex ion in aqueous solution. Careful addition of one drop of Fe to KSCN yields striped patterns after several minutes. The patterns appear reminiscent of Rayleigh‐Taylor instabilities and convection rolls, arguing that pattern formation is caused by density‐driven mixing.
Source: Advances in Physical Chemistry
DOI: 10.1155/2009/350424
Institution: Hofstra University
Language: English
Subfield: Computer Networks and Communications
Field: Computer Science
Domain: Physical Sciences
Open Access status: hybrid
OpenAlex ID: W2005333862