The source of micellar rate enhancements

Micelles have effects on spontaneous reactions which can be related to mechanism and the properties of the micellar surface. Inhibition of bimolecular, micelle-inhibited reactions is also straightforward because micelles keep reactants apart. 

For micelle-assisted bimolecular non-solvolytic reactions it is necessary to consider both medium and proximity effects. 

Analysis of the variation of the overall rate constant of reaction with [surfactant] was discussed in Section 3 (p. 222) and the treatment allows calculation of the second-order rate constants of reaction in the micellar pseudophase. These rate constants can be compared with second-order rate constants in water provided that both constants are expressed in the same dimensions and typically the units are M s. Inevitably the comparison 

Another problem is that different workers make their calculations of second-order rate constants in the micelle in different ways. For example, the surface potential of a micelle may be specifically included in the calculation in order to estimate ion binding, but there is a circularity in this argument because surface potentials are often estimated from micellar effects upon indicator acid-base equilibria which themselves depend upon ion-binding to micelles (Fernandez and Fromherz, 1977). 

Despite all these uncertainties the picture is reasonably self-consistent, in that calculated second-order rate constants in micelles are generally similar over wide ranges of surfactant and reagent concentration and are often little affected by changes in the micellar counterion. Examples are given in Tables 

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