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Title: Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation

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 Fe 3 + with colorless SCN to form the blood-red Fe ( SCN ) 2 + complex ion in aqueous solution. Careful addition of one drop of Fe ( NO 3 ) 3 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.

Authors:
 [1];  [2];  [2]
  1. Department of Chemistry, Hofstra University, Hempstead, NY 11549-1510, USA
  2. Department of Physics and Astronomy, Hofstra University, Hempstead, NY 11549-1510, USA
Publication Date:
Sponsoring Org.:
USDOE
OSTI Identifier:
1198248
Grant/Contract Number:  
FG02-08ER64623
Resource Type:
Published Article
Journal Name:
Research Letters in Physical Chemistry
Additional Journal Information:
Journal Name: Research Letters in Physical Chemistry Journal Volume: 2009; Journal ID: ISSN 1687-6873
Publisher:
Hindawi Publishing Corporation
Country of Publication:
Country unknown/Code not available
Language:
English

Citation Formats

Sobel, Sabrina G., Hastings, Harold M., and Testa, Matthew. Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation. Country unknown/Code not available: N. p., 2009. Web. doi:10.1155/2009/350424.
Sobel, Sabrina G., Hastings, Harold M., & Testa, Matthew. Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation. Country unknown/Code not available. doi:10.1155/2009/350424.
Sobel, Sabrina G., Hastings, Harold M., and Testa, Matthew. Wed . "Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation". Country unknown/Code not available. doi:10.1155/2009/350424.
@article{osti_1198248,
title = {Spatial Heterogeneity and Imperfect Mixing in Chemical Reactions: Visualization of Density-Driven Pattern Formation},
author = {Sobel, Sabrina G. and Hastings, Harold M. and Testa, Matthew},
abstractNote = {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 Fe 3 + with colorless SCN − to form the blood-red Fe ( SCN ) 2 + complex ion in aqueous solution. Careful addition of one drop of Fe ( NO 3 ) 3 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.},
doi = {10.1155/2009/350424},
journal = {Research Letters in Physical Chemistry},
number = ,
volume = 2009,
place = {Country unknown/Code not available},
year = {2009},
month = {5}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record
DOI: 10.1155/2009/350424

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