Reactions Catalysed by Anionic Micelles

Reactions Catalysed by Anionic Micelles.— The success of quantitative analysis of reactions catalysed by cationic micelles has encouraged a more detailed analysis of reactions catalysed by anionic micelles. The hydrolysis of the methyl and ethyl acetals of p-nitrobenzaldehyde in the presence of anionic detergents may be simulated with reasonable accuracy by  

The bromination of phenyl n-pentyl ether is more para-selective in anionic micelles than it is in water. This contrasts with the lower para-selectivity of nitration of bromobenzene in the cationic micelles formed by dissolving lauric acid in 95% H2S04. It is not clear whether these effects are due to substrate orientation or to micelle-induced changes in the selectivity parameter for electrophilic aromatic substitution. The rates of solvolysis of alkyl p-trimethyl-ammoniumbenzenesulphonate trifluoromethanesulphonates (42) are strongly inhibited by anionic micelles of sodium lauryl sulphate or sodium dodecanoate. In water, homomicelles of (42) or sodium dodecanoate micelles, undergo inversion of stereochemistry, but in sodium lauryl sulphate 22% retention of 

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