A QUANTITATIVE STRUCTURE-REACTIVITY STUDY OF MONO-BASIC ORGANOPHOSPHORUS ACIDS IN COBALT AND NICKEL EXTRACTION

Abstract

ABSTRACT The extraction behavior of Co(II) and Ni(II) by a series of dialkylphosphoric acids, mono-esters of alkylphosphonic acids, and dialkyl phosphinic acids was investigated. The quantitative relationship between the structure and properties of these organophosphorus acids in cobalt and nickel extraction was established based on an analysis of the structural factors that determine the reactivities and separation capabilities of these systems. As expected, polar and steric effects of the substi-tuents of ligands play an important role in cobalt and nickel extraction. The fact that Ni(II) extraction is more sensitive to the substituent than Co(II) can be rationalized by the different steric requirements of the various configurations of the complexes formed during the process.