Action of Amphiphilic Layers on the Kinetics of Interfacial Reactions at Liquid/Liquid Interfaces

• DOI: 10.1021/la971044x
• Publication Date: 2002-07-26T05:28:14Z
• Authors: Walter Nitsch; Michael Weigl
• Keywords: Saturation (graph theory); Mass transfer coefficient

This contribution concerns chemical mass transfer between liquid phases with the main question directed to action of adsorbed amphiphilic layers at interface. As model system, complexation zinc ions (aqueous phase) dithizone (toluene was selected, measured stirred cell technique. allows discrimination flow-dependent transport processes from flow-independent interfacial reactions as rate-controlling alternatives. In absence surfactants (the so-called base system) rate is shown be limited by or reactions, depending on level ion concentration. regime slow for flux, a linear dependency and concentration reciprocal first-order influence proton were observed. Because interaction reaction point interest, only cases being independent convection are taken into consideration. For this it first time that presence anionic adsorption alters not constant but all mechanism occurring reaction. The striking results concern appearance saturation kinetic related concentration, disappearance sensitivity, strong inhibition added electrolytes. Moreover, layer acts an accelerator inhibitor controlling reaction, A proposed which explains most experimental in plausible manner. observed equivalent AOT (bis(2-ethylhexyl) sulfosuccinate sodium salt) SDS (sodium dodecyl sulfate), seems justified assume possibility monolayers frequent feature. Preliminary measurements concerning cationic demonstrate behavior consistent interpretation pattern: fluxes inhibited electrostatics.