Synergism and diluent effects in the extraction of cesium by 4-sec-butyl-2-(α-methylbenzyl)phenol (BAMBP)

Abstract

In order to understand better the nature of the extraction of cesium by 4-sec-butyl-2-(α-methylbenzyl)phenol (BAMBP), the effects of various synergistic reagents and diuleutns on the extraction have been studied. The synergistic reagents included di(2-ethylhexyl)phosphoric acid (HDEHP0 and two car☐ylic acids, 4-phenylvaleric acid (HV) and heptadecyl tetrapropenylsuccinic acid (HS). The diluents included octanol-1 (hydrogen bonded, donor type), acetophenone (non-hydrogen bonded, donor type), and chloroform (weakly hydrogen bonded, acceptor type), besides carbon tetrachloride and an aliphatic hydrocarbon. Synergism was slight at pH > 11, increasing in neutral and slightly acid solutions to, e.g. enhancement x > 100 with 0·02 M HV−1 M BAMBP in CCl 4 and X > 1000 with 0·01 M HDEHP-1 M BAMBP in hydrocarbon at pH = 7. The dependence of E a 0 on BAMBP concentration in the presence of HDEHP and HV changed in different pH regions. The extraction chemistry was interpreted primarily on the basis of these extraction data. I.R., NMR, and dielectric constant measurements were used to corroborate and extended our understanding of the nature of the molecular interactions involved in these systems and their effects on the extraction mechanisms. The principal extract species appears to be [Cs·4 BAMBP] + Y −, where Y − represents V −, HV 2 −, or H(DEHP 2 −, plus some species with the anion directly coordinated to cesium: CsY·2 BAMBP and CsV·3 BAMBP.