Cu(II) catalyzed oxidation of L-phenylalanine by hexacyanoferrate(III) in cationic micellar medium

Abstract

The kinetics of Cu(II) accelerated oxidation of L-phenylalanine (Pheala) oxidation in cetyltrimethylammonium bromide (CTAB) by hexacyanoferrate(III) was investigated by registering the decline in absorbance at 420 nm. Employing the pseudo-first-order condition, the reaction's advancement has been examined as an indicator of[CTAB], [Cu(II)], [OH-], [Pheala], [Fe(CN)63-], temperature, and ionic strength. The results show that [CTAB] is the critical parameter with a discernible influence on reaction rate. Pheala interacts with [Fe(CN)6]3- in a 1:2 ratio, and this reaction exhibits first-order dependency with regard to [Fe(CN)63-]. In the investigated concentration ranges of Cu(II), [OH-], and [Pheala], the reaction demonstrates fractional-first-order kinetics. A positive salt effect is indicated by the linear rise in reaction rate with additional electrolytes. CTAB catalyzes the process substantially, and once at its peak, the rate remains basically constant as [CTAB] grows. Reduced repulsion between surfactant molecules' positive charge heads brought on by the negative-charged [Fe(CN)6]3-, OH-, and [Cu(OH)4]2- molecules may be responsible for the witnessed drop in CTAB CMC.