Kinetics, mechanism and cloud point measurements in the oxidative degradation of non-ionic Triton X-100 surfactant in acidic permanganate solutions

摘要

The polyoxyethylene chain of non-ionic surfactant Triton X-100 [4-(1,1,3,3-tetramethylbutyl) phenyl polyethylene glycol, TX-100] was degraded by permanganate in the presence of HClO4. The oxidative degradation rate and cloud point have been obtained as a function of [ surfactant], [ permanganate], [ HClO4], and temperature. Dependence of the reaction rate on adding inorganic salts (Na4P2O7, NaF and MnCl2) was also examined. The oxidation rate increased with increase in [ TX-100] and [H+]. The higher order kinetics with respect to [TX-100] at lower [H+] shifted to lower order at higher [H+]. The cloud point of TX-100 (67 degrees C) shifted to lower temperature ( 23 +/- 0.5 degrees C) after oxidative degradation of the polyoxyethylene chain. Evidence of complex formation between TX- 100 and MnO4- was obtained spectrophotometrically. Presence of the primary alcoholic ( - OH) group in the TX-100 skeleton is responsible for the degradation of oxyethylene chain. Both monomeric and aggregated TX-100 molecules are oxidized by permanganate. A catalytic oxidation mechanism is proposed on the basis of the experimental findings.