The role of premicellar assemblies and micelles upon the hydrolysis of 2-(2-fluorophenoxy)quinoxaline

摘要

In the presence of cationic surfactants (C16H33NR3Cl, R=Me, n-Pr, and n-Bu), the rate-surfactant concentration profiles for the hydrolysis of 2-(2-fluorophenoxyquinoxaline) 1 show a double maxima with increasing surfactant concentration and at high substrate concentration. The first rate maximum is ascribed to the formation of catalytically active substrate-premicellar complexes of 1 with the surfactant and the second rate maximum to reaction in micelles. At low substrate concentration, a single maximum is observed. A change of head group in the sequence Me3N+>, Pr3N+>, Bu3N+> increases the second-order rate constant for the hydrolysis of compound 1.