The Extraction of Cobalt(II) From Oxalate Solutions by Aliquat-336 Dissolved in Chloroform

Abstract

A study is reported of the extraction of cobalt(II) from oxalate solutions by Aliquat 336 in chloroform. Equilibrium studies by two-phase titration show that the predominant organic-phase complex has the formula [(R₃MeN)₂Co(C₂O₄)₂]. It is proposed that this species is formed by extraction of the anionic complex Co(C₂O₄)₂^2- involving interfacial reactions. There is evidence for the formation of a small amount of the complex [(R₃MeN)₄Co(C₂O₄)₃]. The extraction mechanism proposed is based on a study with the single-drop technique, and is supported by interfacial tension measurements and measurements with a stirred cell of constant interfacial area.