Reaction of cis-diaqua nitrilotriacetatochromate(III) with L-ascorbic acid: A kinetic study

Abstract

The kinetics of the reaction of L-ascorbic acid (H(2)A) with cis-[Cr(NTA)(H2O)(2)] has been studied over the range 0.02less than or equal to[H(2)A](T)less than or equal to 0.1 mol dm(-3), 3.16 less than or equal to pH less than or equal to 4.64, 20.0 less than or equal to t less than or equal to 35.0degreesC, 0.2 less than or equal to I less than or equal to 1.0 mol dm(-3) (NaClO4) and 10% less than or equal to [MeOH] less than or equal to 50% (v/v). The rate of the reaction is found to increase with the increase in pH of the medium. The reaction is hardly affected by change in ionic strength and dielectric constant of the medium. Activation parameters, DeltaH(#) and DeltaS(#) have been found to be 39.4, 34.1, 102.0 kJ mol(-1) and -168.00 +/- 0.15, -208.0 +/- 0.35, 53.0 +/- 1.4 J K(-1)mol(-1) for k(1), k(-1) and k(2) path respectively. Anation of cis-[Cr(NTA)(H2O)(2)] and [Cr(NTA) (OH2)(OH)](-) follow Ia and Id path respectively.