Extraction of some mineral acids by tri‐n‐octyl phosphine oxide

Abstract
The distribution equilibria of hydrochloric, nitric, perchloric, sulphuric and phosphoric acids between aqueous solutions and a solution of tri‐n‐octyl phosphine oxide (TOPO) in organic solvents have been investigated. The organic phases were studied by infrared and nuclear magnetic resonance spectroscopy. As a result, it is found that the extraction of these acids is governed by the formation of HCl·TOPO, HNO3·TOPO and HClO4·TOPO, of H2SO4·2 TOPO and H2SO4·TOPO, and of H3PO4·3 TOPO, H3PO4·2 TOPO and H3PO4·TOPO, respectively.