Kinetics and mechanism of the reaction of lysine with permanganate ion at different ionic strengths and temperatures

The kinetics of Mn(VII) oxidation of lysine in moderately sulfuric acid solutions was studiedspectrophotometrically in the presence and absence of Mn(II) as catalyst. The reaction was arrangedto be under pseudo first-order condition with respect to Mn(VII). The results showed that the pseudofirst-order rate constant increases with increasing [H2SO4], [(Mn)II], and [lysine]. The dependence ofthe reaction rate on temperature (20 to 40 °C) and on ionic strength (0 to 0.12 mol dm-3 NaCl) wasalso studied. The obtained results showed that the activation energy and H# decrease but S#increases by increasing the ionic strength. Finally, an equation was derived to calculate the activationenergy dependence on ionic strength based on a Debye-Huckel type equation and a mechanism wasproposed consistent with the observed results.