Acidic hydrolysis of hydroxamic acids in mixed cationic-cationic, cationic-nonionic and anionic-nonionic micelles

Acidic hydrolyses of some carbon and nitrogen substituted hydroxamic acids (R-C(O) N(OH)R', R = CH3, R'=H; R=C6H5, R' = H; R = C6H5, R' = C6H5, R = C6H5, R' = 4-CH3-C6H4) have been studied at 55 degreesC in mixed micellar solution of surfactants (cationic - cationic, cationic-nonionic and anionic - nonionic). The results indicate that addition of nonionic surfactant to an acid solution of anionic surfactant (SDS) strongly decreases the observed rate constant. In other mixed micellar systems inhibition has been observed. Binding constants and rate constants for the reaction in the micellar pseudophase, obtained from the kinetic analysis, have been reported. The inhibition effects depend on the hydrophobic chain length of the surfactants and the hydrophobicity of the substrate.