Abstract
The kinetics of phenylalanine (phe)oxidation by permanganate has been investigated in absence and presence of cetlytrimethylammonium bromide(CTAB) using conventional spectrophotometric technique. The rate shows first- and fractional-order dependence on [MnO4-] and [phe] in presence of CTAB. At lower values of [CTAB] (<= 10.0 x 10(-4) mol dm(-3)). the catalytic ability of CTAB aggregates are strong. In contrast, at higher values of [CTAB] (<= 10.0 x 10(-4) mol dm(-3)), the inhibitory effect was observed in absence of H2SO4. We find that anions (Br-, Cl- and NO3-) in the form of sodium salts are strong inhibitors for the CTAB catalyzed oxidation. Kinetic and spectrophotornetric evidences for the formation of an intermediate complex and ail ion-pair complex between phe and MnO4-, CTAB and MnO4-, respectively, are presented. A mechanism consistent with kinetic results has been discussed. Complex formation constant (K-c) and micellar binding constant (K-s) were Calculated at 30 C and found to be K-c = 319 mol (1) dm (3) and K-s = 1127 mol (-1) dm (-3), respectively. (C) 2008 Elsevier B.V. All rights reserved.