The rate of reduction of Cr(VI) to Cr(III) in 0.05 M K2Cr2O7 has been studied and was found to be first order. The rate of reaction was measured in the absence of amino compounds and in the presence of o-nitroaniline, p-nitroaniline, m-toulidine, p-chloroaniline, and o-bromoaniline at four different temperatures. The rate of reaction was found to decrease with the addition of amines. Thermodynamic parameters DeltaG*, DeltaH*, and DeltaS* were calculated from the study. (C) 2004 Elsevier Inc. All rights reserved.