The extraction of copper(I), lead(II) and tin(IV) from hydrochloric acid by solutions of tetra-n-hexylammonium chloride in ethylene dichloride

Copper(I) is strongly extracted from chloride media as the ion-pair NR₄+CuCl₃-by solutions of tetra-n-hexylammonium chloride (NR₄+Cl-) in ethylene dichloride. The distribution coefficient decreases from ca. 100 in 1 M chloride but is still as high as 13 in 10 M chloride. The extraction of lead(II) is shown to be due to the partition of the ion-pair (NR₄+PbCI₃-). The percentage of 0.0018 M lead extracted is 98% from 0.58 M hydrochloric acid and falls to 38% from 7.8 M acid. The distribution coefficient decreases rapidly with the total lead concentration. The extractions of tin(IV) increased to a maximum of 99.5% in ca. 5 M hydrochloric acid but decreased rapidly above 6 M acid. It proved impossible to identify the extractable species.