SUBSTRATE STRUCTURAL EFFECTS IN MICELLAR CATALYSIS WITH PERFLUOROOCTANOIC ACID

Rates of hydrolysis of a series of hydroxamic acids in aqueous acetonitrile, with perfluorooctanoic acid serving as a reactive counterion surfactant, have been determined. The pseudophase ion exchange model satisfactorily explains the surfactant effects. Variation in the structure of the hydrophobic moiety of the hydroxamic acid substrates was obtained by the incorporation of different chain lengths and differently substituted aryl groups into the substrate. The major influence of the change in substrate structure is on the binding constant for binding of the substrate to the surfactant aggregate. The number of substitutions on the aryl ring appears to be more important than the total number of carbon atoms in the substrate.