Liquid-liquid extraction of vanadium(V) from sulfate media with diisododecylamine

The liquid-liquid extraction of vanadium(V) from sulfate media with diisododecylamine (DIDA), a new reagent providing an alternative to the well-known trioctylamine-based extractant, has been investigated at 22°C with toluene and kerosene as diluents. DIDA efficiently recovers vanadium(V) from weakly acidic solutions (pH 5–6), yielding a DIDA: V = 1: 2.5 (mol/mol) complex in the organic phase. Vanadium is completely reextractable from the organic phase with an NH₄OH solution (1: 1). IR spectroscopic studies and Karl Fisher determination of the water content of the extracts have demonstrated that vanadium extraction is due an interfacial anion-exchange reaction (log K _ex = 1.6–1.7) yielding amine association species containing inverse micelles.