POLYFUNCTIONAL DERIVATIVES OF IMIDODIPHOSPHORIC ACID AS EXTRACTANTS

The distribution of calcium, strontium, barium and scandium between aq ueous and organic phases was studied using 0.1 M HNO3 or 0.01 to 0.1 M HCl as the aqueous phase and solutions of selected derivatives of org anophosphoric reagents containing the conventional =P(O)NHP(O)= bifunc tional group or the analogous trifunctional or tetrafunctional group i n various organic solvents as the organic phase. The effect of substit ution of one ester group by an OH or NH2 group was examined. While for the alkaline earth metals the distribution ratio increases if the bif unctional group is replaced by a higher-functional group, the reverse is true for scandium. The extraction efficiency is improved by the pre sence of OH or NH2 substituent groups. The composition of the extracte d species was inferred by logarithmic analysis and the corresponding e xtraction constants were calculated.