Electrode reaction of ferrocene in a nitrobenzene plus water emulsion

Citation
Jy. Chen et al., Electrode reaction of ferrocene in a nitrobenzene plus water emulsion, J ELEC CHEM, 496(1-2), 2001, pp. 88-94
Citations number
22
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Spectroscopy /Instrumentation/Analytical Sciences
Journal title
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
ISSN journal
1572-6657 → ACNP
Volume
496
Issue
1-2
Year of publication
2001
Pages
88 - 94
Database
ISI
SICI code
Abstract
Nitrobenzene (NB) including ferrocene was mixed vigorously with the sodium dodecylsulfate aqueous solution to yield an oil-in-water emulsion. Voltammo grams of the emulsion showed an anodic wave at approximately 0.90 V versus Ag \ AgCl, which was discerned from the oxidation wave of micellized ferroc ene in water (at 0.29 V), that of directly soluble ferrocene (at 0.22 V) an d also that of ferrocene in NB (at 0.55 V). From dependence of the anodic c urrent on the scan rate, the anodic wave was due to the adsorption on oil d roplets including ferrocene. In contrast, a cathodic wave was only the redu ction of the soluble ferrocinium ion at 0.15 V. Consequently, ferrocene, wh ich is known as an electrochemically reversible couple, behaves as an irrev ersible system in the emulsion. When a potential of more than 1.2 V was app lied, the emulsion was gradually separated into the oil and the aqueous pha ses, regardless of the presence or absence of ferrocene. A possible reactio n mechanism is adsorption of oil droplets containing ferrocene at the elect rode, an increase in the interfacial energy with the application of the pos itive potential, coalescence of the droplets, dispersion of ferrocene in th e water phase, and the oxidation of the ferrocene at the electrode. An opti cal microscopic view showed spheres of oil less than 7 mum in diameter. The emulsions were stable for a few weeks without agitation. (C) 2001 Elsevier Science B.V. All rights reserved.