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Kinetics and mechanism of oxidation of diethanolamine (DEA) and triethanolamine (TEA) by potassium bromate in presence of ruthenium(III) chloride as homogeneous catalyst in perchloric acid medium have been investigated. First order kinetics with respect to each of [KBrO3] and [Ru(III) chloride] was observed in the oxidation of both DEA and TEA. With about eight-fold variation in [DEA] and 10-fold variation in [TEA], first order kinetics in [substrate] was observed up to nearly 3-fold variation in [DEA] and 5-fold variation in [TEA]. Kinetics with negative effect of [substrate] became more complex in both cases when a significant decrease in pseudo first order rate constant was observed at their higher concentrations. Inverse fractional order in [H+] was noted throughout its 10-fold variation. Variation in [Hg(OAc)2], [Cl–] and ionic strength (μ) of the medium did not bring about any significant change on the rate of reaction. The values of rate constants observed at four different temperatures were utilised to calculate the activation parameters. Acetic acid and ammonia have been identified as main oxidation products of the reactions. A suitable mechanism involving the formation of a complex between [Ru(III)–aminoalcohol] complex and bromate ion prior to the rate-determining step is proposed.

The kinetics of Ir(III)-catalysed and Hg(II)-co-catalysed oxidation of D-glucose (Glu) and D-fructose (Fru) by N-bromoacetamide (NBA) were studied in acidic medium. The reactions follow identical kinetics, being zero order in each sugar concentration. The experimental results show a first-order dependence on NBA and Ir(III) at low concentrations, but tending towards zeroth order at higher concentrations. A negative effect of variation of [H⁺], [Cl⁻] and [NHA] was observed whereas the ionic strength (I) of the medium has no influence on oxidation rate. The important feature of the reaction is that it follows a second-order dependence on mercury(II) ion concentration at low concentrations, but it tends towards first order at higher concentrations. Various activation parameters were calculated and recorded. The corresponding acids were identified as the main oxidation products of the reaction. On the basis of the experimental findings, a suitable mechanism consistent with the observed kinetics was proposed. A comparative study was also made between the kinetic results of the present investigation and those of Ru(III)- and Pd(II)-catalysed oxidations of reducing sugars. Copyright © 2004 John Wiley & Sons, Ltd.