US EPA

1468121 

Journal Article 

Reactivity and models for anion distribution: specific iodide binding to sulfobetaine micelles 

Farrukh, MA; Beber, RC; Priebe, JP; Lal Satnami, M; Micke, GA; Costa, AC; Fiedler, HD; Bunton, CA; Nome, F 

2008 

1 

Langmuir
ISSN: 0743-7463
EISSN: 1520-5827 

24 

22 

12995-13000 

English 

18950202 

10.1021/la802179m 

WOS:000260874800041 

https://www.scopus.com/inward/record.uri?eid=2-s2.0-57349138495&doi=10.1021%2fla802179m&partnerID=40&md5=3db91b4d096c2fa53bc1bedc65ba5aeb
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The reaction of I (-) with methyl naphthalene-2-sulfonate (MeONs) is accelerated by the micellized sulfobetaine surfactants N-decyl, N-dodecyl, N-tetradecyl, and N-hexadecyl- N, N-dimethylammonio-1-propanesulfonate. Concentrations of micellar-bound I (-) were determined by using ion-selective electrodes (ISE), and capillary electrophoresis. At low concentrations, I (-) incorporation fits Langmuir isotherms and is related to changes in micellar surface potentials. Rate effects of dilute KI are fitted quantitatively by a pseudophase model that describes I (-) binding in terms of a sorption isotherm, but at higher [KI], where the simple model predicts saturation, rates increase due to electrolyte invasion. This model considers transfer equilibria of both reactants between water and micelles and second-order rate constants in each pseudophase. Estimated second-order rate constants for reaction of MeONs with I (-) in the micellar pseudophase are 3.2- to 3.5-fold higher than the second-order rate constant, k 2w, in water, depending on surfactant structure and assumptions in the treatment.