Cu(II) promoted oxidation of L-valine by hexacyanoferrate(III) in cationic micellar medium

Abstract

The kinetics of Cu(II) accelerated L-valine (Val) oxidation by hexacyanoferrate(III) in CTAB micellar medium were investigated by measuring the decline in absorbance at 420 nm. By adjusting one variable at a time, the progression of the reaction has been inspected as a function of [OH−], ionic strength, [CTAB], [Cu(II)], [Val], [Fe(CN)63−], and temperature using the pseudo-first-order condition. The results show that [CTAB] is the critical parameter with a discernible influence on reaction rate. [Fe(CN)6]3- interacts with Val in a 2:1 ratio, and this reaction exhibits first-order dependency with regard to [Fe(CN)63−]. In the investigated concentration ranges of Cu(II), [OH−], and [Val], the reaction demonstrates fractional-first-order kinetics. The linear increase in reaction rate with added electrolyte is indicative of a positive salt effect. CTAB significantly catalyzes the process, and once at a maximum, the rate remains almost constant as [CTAB] increases. Reduced repulsion between surfactant molecules' positive charge heads brought on by the negatively charged [Fe(CN)6]3-, OH−, and [Cu(OH)4]2- molecules may be responsible for the observed drop in CMC of CTAB.