Hydroxylamine derivatives in the Purex process - Part VII: the redox reactive kinetics and mechanism of dimethylhydroxylamine and vanadium (V) in nitric medium

摘要

The kinetics of the redox reaction between dimethylhydroxylamine (DMH) and vanadium(V) in nitric acid has been studied by spectrophotometry at 23.1 0C. The rate equation of the reaction is determined as -d[V(V)1/dt=k[V(V)[DMH] by investigating the influence of the concentrations of V(V) and DMH acidity, ionic strength and the ratio of the initial concentrations of reactants on the redox reaction. The rate constant of the reaction k= 9.95±0.52 (mol/l){sup}(-1)·s{sup}(-1) when the ionic strength is 1.00 mol/l. The activation energy of the reaction is 22.1 kJ/mol. A possible mechanism of the redox reaction has been suggested on the basis of an electron spin resonance(ESR) spectrum of dimethyl nitroxyl radical, (CH{}sub3){sub}2NO.