Solvent Extraction of Indium(III) with Bis(2-Ethylhexyl) Phosphinic Acid in Toluene

Abstract

Extraction equilibrium data is obtained for distribution of indium(III) between bis(2-ethylhexyl) phosphinic acid dissolved in toluene and acidic aqueous nitrate media. The stoichometry of the extracted species is determined on the basis of slope analysis and IR spectra. The extraction of indium(III) proceeds by a cation exchange mechanism and the extracted species is InR₃·3HR. Temperature dependence of the extraction equilibrium is examined by temperature variation method to estimate apparent thermodynamic functions (ΔH, ΔS and ΔG). The extraction process is exothermic in nature and an increase in temperature is not favorable.