Affiliation: School of Chemistry & Biochemistry, Thapar University, Patiala, 147004, India.
The influence of different protic and aprotic solvents on the conductometric titrations of cerium(III) with EDTA has been studied. The results are explained for mixed solvent systems using 1,4-dioxane (DA), acetonitrile (ACN), Dimethylsulphoxide (DMSO), N,N’-dimethylformamide (DMF), Tetrahydrofuran (THF) and Methanol (MA) as cosolvents. End points of conductometric titrations improved in presence of 1,4 dioxane as a co-solvent (in comparison to that in aqueous medium) for binary mixtures of Ce(III) with Al(III), Cu(II), Mn(II) and Pb(II), respectively. Composition of co-solvent-solvent medium has been optimized for best conductometric titration results. On the basis of synergic effect of dielectric constant, proton affinity and extent of solvation relative order of co-solvents showing increasing effect has also been proposed. It is now possible to determine Ce(III) in presence of Al(III) without interference in aqueous medium in presence of 20% 1,4 dioxane.