SYNERGIC EXTRACTIONS OF INDIUM(III) FROM CHLORIDE AND PERCHLORATE MEDIA WITH 1-PHENYL-3-METHYL-4-ACYLPYRAZOL-5-0NES AND TRI-n-OCTYLPHOSPHINE OXIDE MIXTURES IN TOLUENE

Abstract

ABSTRACT The synergic mixtures of extractants HL + TOPO where HL = l-phenyl-3-methyl-4-acylpyrazol-5-one, acyl = benzoyl (HPMBP), thenoyl (HPHTP), lauroyl (HPMLP) and with TOPO = tri-n-octylphos-phine oxide, are studied by IR, PMR and 31P NMR spectroscopies and by liquid-liquid distribution analysis. In toluene solutions, the “acylpyrazolones” are, in fact, chelated 4-acyl-5-hydroxy-pyrazoles ; addition of TOPO weakens this intramolecular H-bond by formation of H-bonded (TOPO.HL) complexes (log Kc -˜, 1.1) ; the chelate ring may be broken (HPHTP) or subsist (HPMBP, HPMLP) in these complexes. Solid HPMBP exists either as chelated 4-acyl-5-hydroxypyrazole (yellow solid, F = 92°C) or as “open” 4-acyl-5-hydroxypyrazole with strong intermolecular H-bonds (white solid, F = 1150C). Extraction of indium with the extraction solvents studied, from CI /C104aqueous solutions.takes place according to the four-equilibria (x = 0 to 3) : The constants Kxare determined : KO˜ K1> K2> K3; HPMBP is the best extractant in all...