Kinetic studies on the complexation of aqua chromium (III) with DL-leucine in aqueous acidic media

Abstract

Kinetics of formation of 1:2 complex between chromium (III) and DL- leucine was studied spectrophotometrically at λ(max)=540 nm. The reaction was found to be first order in both reactants, increasing hydrogen ion concentration from 2.5x10-5a 10-3mol.dm-3decreased the reaction rate: k(obs)=a+b[H+]-1. Activation parameters were evaluated to be 38 kJ.mol-1and -159 JK-1.mol-1, for the enthalpy and entropy of activation respectively. A value of log K=2.9 at 42°C was obtained for the formation constant of the complexe O.