Distribution Equilibria of Five β-Diketones and Their Complexes of Copper(II) and Iron(III) in 4-Methyl-2-pentanone-Aqueous Perchlorate Solution Systems

抄録

Chemical equilibria of liquid-liquid distributions of acetylacetone, benzoylacetone, trifluoroacetylacetone, benzo-yltrifluoroacetone, and hexafluoroacetylacetone, (HA), and solvent extraction of Cu(II) and Fe(III) with these β-diketones were determined in 4-methyl-2-pentanone(MIBK)-aqueous perchlorate solution systems. The results are compared with those obtained in systems where carbon tetrachloride is the solvent. The distribution constant of HA in the MIBK systems is higher when the acid is stronger. This dependence is opposite to that found in the carbon tetrachloride systems. The extraction of Cu(II) into MIBK with the β-diketones having trifluoromethyl group is better than into carbon tetrachloride. However, such a better extraction is usually not found with acetylacetone and benzoylacetone. Although iron(III) is extracted as cationic chelates with perchlorate ions into MIBK, its extraction as the FeA₃ chelate with the, β-diketones is in most cases poorer than into the latter solvent. Two types of equilibrium constants for the metal extraction were calculated, they are critically discussed.