Studies of the Ce(III)/Ce(IV) couple in multiphase systems containing a phase transfer reagent—I. Conditions for the extraction of Ce(IV) and electrode kinetics

✍ Scribed by Derek Pletcher; Erika M. Valdes

• Publisher: Elsevier Science
• Year: 1988
• Tongue: English
• Weight: 714 KB
• Volume: 33
• Category: Article
• ISSN: 0013-4686
• DOI: 10.1016/0013-4686(88)80167-1

✦ Synopsis

The factors influencing the transfer of Ce(IV) from aqueous solutions to organic solvents using either tetrabutylammonium ion or trihutylphosphate as the extractant are investigated. It is shown that extraction is efficient from acidic nitrate solutions but that other anions, particularly sulphate decrease the extent of transfer; in contrast Ce(II1) always extracts only very poorly, if at all. Cyclic voltammetry has been used to study the Ce(III)/Ce(IV) couple. In acidic aqueous nitrate, the formal potential is independent of both proton and nitrate concentrations while the standard rate constant increases with added proton but is independent of nitrate concentration. Added sulphate causes a shift in formal potential to less positive values and a marked deceleration in the rate of electron transfer. In organic solvents the characteristics for the couple depend on the exact conditions but the kinetics of electron transfer can remain fast.