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 studied spectrophotometrically in the presence and absence of Mn (II) as catalyst. The reaction was arranged to be under pseudo first-order condition with respect to Mn (VII). The results showed that the pseudo first-order rate constant increases with increasing [H2SO4], [(Mn) II], and [lysine]. The dependence of the reaction rate on temperature (20 to 40oC) and on ionic strength (0 to 0.12 mol dm-3 NaCl) was also 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 activation energy dependence on ionic strength based on a Debye-Huckel type equation and a mechanism was proposed consistent with the observed results.