Reaction kinetics of hydrated electrons in a quaternary micro emulsion system: A pulse radiolysis study

Abstract

The pulse-radiolysis technique has been employed to produce and study the kinetics of hydrated electrons in a quaternary micro emulsion (Sodium Lauryl Sulfate electrons vary smoothly as the water droplet sizes are changed. The bimolecular rate constants for the reaction of with different solutes have been determined. It has been observed that Ϫ e aq the measured bimolecular rate constants for the reaction of hydrated electrons with different solutes are indicative of the solubilization sites, the water core sizes, and the surrounding environment.

Kinetics of Free Radical Reactions of Some Biologically Important Compounds as Studied by Pulse Radiolysis

“…Perhaps reverse micelles and microemulsions can, therefore, to some extent, model these pools of water. Some very interesting pulse radiolysis information obtained recently in a four-component microemulsion has already been discussed [78,79,81,93]. This work suggests that the free radical reactions occurring in these small pools are considerably slower than in bulk water.…”

“…The following discussion is with reference to a microemulsion consisting of SDS/water/1-pentanol/cyclohexane used in recent studies [78,79] following the method developed by Petit et al [77] but in a simpler way. The decay of the hydrated electron with time in a microemulsion obeys the following kinetic equation:…”

“…The slope being close to -2 or -3 means that the solubilization site is at the interface or within the water pool, respectively. A typical plot is shown in Figure 8, which shows that the big protein molecule bovine serum albumin (BSA) stays at the interface up to a certain W o , whereas N, N-dimethylformamide remains in the aqueous core [78,79].…”

“…The variation of ln P 0 (s) and ln (A 0 ′/A′) (q) with BSA concentration at W 0 = 24, at t = 3 s[79].…”