The extraction of cobalt(II) from lithium chloride solutions by aliquat 336^R dissolved in chloroform

Abstract

The extraction of cobalt(II) by Aliquat 336^R from 7 M lithium chloride solutions involves two species from the aqueous phase, COCl₄² and CoCl₃^-, with the former being the predominant one. The equilibrium constants for the formation of the extracted complexes (R₃MeN⁺)₂ CoCl₄^2- and R₃MeN⁺CoCI₃^- are: logK_ll 5.01 and logK₁₂ 9.55.

From the results of experiments by means of the single-drop technique, a mechanism is proposed based on the formation of interfacial complexes by fast ion-exchange with a rate-determining step which involves the replacement at the interface of the complex (R₃MeN⁺)₂ COCl₄^2- by two molar proportions of reagent from the bulk organic phase.