Effects of critical points of two microemulsion systems on the reaction rate of basic hydrolysis of crystal violet

Abstract The pseudoternary phase diagrams of surfynol465/ n -butanol/ n -hexane/0.006 mol/L NaOH aqueous solution with k m  = 5/3 and surfynol465/ n -butanol/ n -hexane/0.006 mol/L NaOH-heavy water solution with k m  = 5/3 (where k m is mass ratio of surfynol465 to n -butanol) have been constructed. In the corresponding O/W regions of these two microemulsion systems, the kinetics of the basic hydrolysis of crystal violet has been investigated near and far away from their respective critical points by using UV spectrophotometer. It was found that no critical effects were observed in these two systems. For the first reaction system, the experimental results obeyed the Griffiths-Wheeler rule; however, it was not consistent with the prediction by the Griffiths-Wheeler rule for the second reaction system. This discrepancy of theory and experiment for the second reaction system may be related to the isotope exchange of H and D. This work extended the studies of critical effect on the chemical reaction to O/W microemulsion as reaction medium.