The synthesis of N'N-dimethyldodecylamine N-oxide in aqueous solutions
by micellar autocatalysis was investigated. Micellar autocatalysis is
a novel variation of conventional micellar catalysis in which surfact
ant micelles catalyze the reaction by which the surfactant itself is s
ynthesized. The lipophilic reactant, dimethyldodecylamine, was initial
ly solubilized in micellar solutions of the amine oxide surfactant, re
sulting in substantially higher reaction rates. Amine conversions of 9
0-100% were obtained within 2 h at 70 degrees C. The effects of reacta
nt concentrations, temperature, and initial surfactant concentration w
ere studied. For systems with no surfactant at time zero, the system w
as initially an emulsion and reaction rates were low. A sharp increase
in the rate was observed when enough surfactant had been produced to
form micelles. Activation energy calculations indicate that enhancemen
ts of the rate were due primarily to the localized concentration of re
actants in the micelle. A simple pseudophase model was used to model r
eactions under pseudo-first-order reaction conditions.