Effects of head group size on the reaction methyl 4-nitrobenzenesulfonate + Br− in water-ethylene glycol cetyltrialkylammonium bromide micellar solutions

✍ Scribed by María Amalia Rodríguez; María Muñoz; María del Mar Graciani; Gaspar Fernández; María Luisa Moyá

• Publisher: John Wiley and Sons
• Year: 2007
• Tongue: English
• Weight: 267 KB
• Volume: 39
• Category: Article
• ISSN: 0538-8066
• DOI: 10.1002/kin.20237

✦ Synopsis

Abstract

The reaction methyl 4‐nitrobenzenesulfonate + Br^−^ has been studied in water‐ethylene glycol cetyltrialkylammonium bromide (alkyl = methyl, ethyl, propyl, and butyl) micellar solutions by changing surfactant concentration as well as the weight percentage of ethylene glycol present in the bulk phase. The pseudophase model was adequate to rationalize quantitatively the micellar kinetic effects. Information about the influence of the head group size on the second‐order rate constant of the process and on the binding equilibrium constant of the organic substrate to the cationic micelles in water–ethylene glycol mixtures was obtained. Kinetic data taken from the literature were compared to those obtained in this work in order to examine the different effects produced by an alcohol that is localized in the bulk phase, such as ethylene glycol, with those caused by an alcohol that distributes between the bulk and micellar pseudophases, such as 1‐butanol. © 2007 Wiley Periodicals, Inc. Int J Chem Kinet 39: 346–352, 2007