Reactivity of Ethanolamines with Ni(III) in Aqueous Solution: Control by Enthalpy & Entropy of Activation

Abstract

Ethanolamine (EA), diethanolamine (DEA) and triethanolamine (TEA) react with Ni(III) in aqueous solution via an innersphere electron transfer mechanism. The orders in [substrate] and [oxidant] are fractional and one respectively suggesting formation of a complex (<em>K</em>-path) between the substrate and the oxidant, which decomposes (<em>k</em>-path) in a rate-determining step. Thermodynamic and activation parameters of <em>K </em>and <em>k </em>paths have been determined and discussed. Solvent immobilization due to generation of a proton in the rate-determining step leads to the negative activation entropies. In addition the rates increase with increase in [H⁺].