Kinetics and mechanism of the reaction of uranyl ion with thenoyltrifluoroacetone
Abstract
The kinetics and equilibrium of the reaction of thenoyltrifluoroacetone and uranyl ion [UO2]2+ to form the mono complex have been studied in aqueous solution at 25 °C and 1.0 mol dm–3 ionic strength. The value of the equilibrium constant, K1 for reaction (i) where HA represents the undissociated form of thenoyltrifluoroacetone, [UO2]2++ HA ⇌[UO2E]++ H+(i) is 0.14 ± 0.02. The kinetic data are consistent with a scheme in which [UO2]2+ reacts with the enol form of the ligand. The rate constants for reaction of [UO2]2+ with HE, the undissociated form of the enol tautomer, and with E– the enolate ion are 1 × 104 and
3 × 105 dm3 mol–1 s–1 respectively.