Kinetic Study of the Reaction of Leuco Methylene Blue with 2,6-Dimethyl-p-benzoquinone in a Reverse Micellar System

Abstract

The kinetics of the reaction of leuco methylene blue (MBH) with 2, 6-dimethyl-p-benzoquinone (DMBQ) were studied in a heptane/ bis (2-ethylhexyl)sulfosuccinate (AOT)/water reverse micellar system. The pseudo-first-order rate constant (k obsd) obtained in the presence of excess of DMBQ was found to be proportional to the initial concentration of DMBQ for W 0 = 3, 5, 10, 15, and 20 (W 0 = [H 2 O] / [AOT]). The second order rate constant (k 2 = k obsd / [DMBQ] 0) increased with an increase in the W 0-value, but was almost independent of the concentration of the water pool. A mechanism involving the distribution of DMBQ between the reverse micellar interface and bulk organic solvent was proposed to explain these findings.