화학공학소재연구정보센터
Separation Science and Technology, Vol.39, No.15, 3573-3599, 2004
Solvent extraction of iron(III) from acidic chloride media using N,N'-dimethyl-N,N'-dibutylmalonamide
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