The effects of zwitterionic surfactant systems upon aromatic nucleophilic substitution

Abstract

Reactions of OH^– with 4-chloro-3,5-dinitrobenzoic acid (1) and 2-chloro-3,5-dinitrobenzoic acid (2) have been examined in solutions of N,N-dimethyl-N-tetradecylglycine (DTG) and N,N-dimethyl-N-hexadecylglycine (DHG). DTG and DHG inhibit hydroxydehalogenation of (1) and kinetic profiles for this reaction tend towards a plateau which assumes different values depending on the pH; hence the inhibition does not stop the reaction. Reactions of (2) with OH^– in the presence of DTG and DHG exhibit a ‘non-effect’. The important factor underlying this difference of behaviour between (1) and (2) in the presence of zwitterionic surfactants is probably the orientation of the substrates within the micro-aggregates.