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

Abstract

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.

Acknowledgement Financial support from Decanato de Investigaciones Científicas, Universidad Simón Bolívar (Grant DI-CB-S100117), Caracas, Venezuela, is gratefully acknowledged.