| Abstract |
In the present paper, a new, simple, and effective method for iron(III) extraction from acidic chloride solutions is described involving the use of a N,N,N ,N -tetrasubstituted malonamide, N,N -dimethyl-N,N -dibutylmalonamide (DMDBMA). The behavior of this ligand towards iron(III) extraction was investigated for different experimental conditions with a particular emphasis on the influence of HCl, LiCl, and ligand concentrations. The extraction behavior of DMDBMA is compared with the ones shown by two similar malonamide derivatives, N,N -dimethyl-N,N -diphenylmalonamide (DMDPHMA) and N,N -dimethyl-N,N -diphenyltetradecylmalonamide (DMDPHTDMA), previously studied. The mechanism involved on iron(III) extraction, the structure of the metal-adducts formed, and also the relationship between the extraction mechanism and the ligand structures are clarified. Therefore, hydrochloric acid extraction, slope analysis, and spectroscopic data-UV and NMR-were used to collect information on the iron(III) extraction reactions. A solvation mechanism involving iron(III) extraction as chlorocomplexes such as HFeCl4 and FeCl3 is proposed. From aqueous feed solutions with HCl concentrations higher than 4 M, iron(III) is mainly extracted as the anionic chlorocomplex, while from solutions with lower HCl concentrations (2 M
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