title: Conductometric, surface tension, and kinetic studies in mixed SDS-Tween 20 and SDS-SB3-12 micellar solutions.
abstract: Micellization in sodium dodecyl sulfate (SDS)-N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate and SDS-polyoxyethylenesorbitan monolaurate binary surfactant solutions was studied by means of conductivity and surface tension measurements. These studies showed that two types of micellar aggregates are present in the mixed micellar solutions. Two reactions were investigated in these micellar media, the oxidation of 1-methoxy-4-(methylthio)benzene by IO(4)(-) and the spontaneous hydrolysis of phenyl chloroformate. Information on the distribution of reagents in the micellar reaction media was obtained through conductivity and spectroscopic measurements. Discussion of the kinetic data showed that the redox reaction takes place mainly in the aqueous phase of the mixed solutions, whereas hydrolysis occurs in the aqueous as well as in the micellar pseudophase. Variations in the observed rate constants of the two processes studied are gradual within the whole surfactant concentration range investigated, revealing little information about the mixed micellar medium.
authors.affiliation: Departamento de Química Física, Universidad de Sevilla, C/Profesor García González s/n, 41012 Sevilla, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Muñoz
authors.forename: Amalia
authors.initials: A
authors.lastname: Rodríguez
authors.forename: María Del Mar
authors.initials: Mdel M
authors.lastname: Graciani
authors.forename: María Luisa
authors.initials: ML
authors.lastname: Moyá
mesh_terms: D003217:Conductometry / Q000379:methods; D007700:Kinetics; D008823:Micelles; D011136:Polysorbates / Q000737:chemistry*; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D013500:Surface Tension
chemical_list: D008823:Micelles; D011136:Polysorbates; D000644:Quaternary Ammonium Compounds; D012996:Solutions; C034730:zwittergent 3-12; D012967:Sodium Dodecyl Sulfate