1850-1855The kinetics of the ruthenium(III)
catalysed oxidation of L-phenylalanine by
alkaline permanganate has been studied spectrophotometrically using a rapid
kinetic accessory. The reaction is first order each in [oxidant] and [catalyst]
with an apparent less than unit order each in [substrate] and [alkali]
respectively. The results suggest the formation of a complex
between the phenylalanine and the
hydroxylated species of ruthenium(III). The complex reacts further with the
alkaline permanganate species in a rate-determining step, resulting in the
formation of a free radical, which again reacts with the alkaline permanganate
species in a subsequent fast step to yield the products. The reaction constants
involved in the mechanism and the activation parameters have been calculated.
There is a good agreement between observed and calculated rate constants under
different experimental conditions