Koichi Yamamoto, S. Inada
Jul 1, 1992
Citations
0
Influential Citations
11
Citations
Journal
Analytical Sciences
Abstract
The solvent extraction of ion associates of tetrahalogenoaurate(III) ions, AuX^−_4(X^−=chloride or bromide), with quaternary ammonium cations (Q^+) has been studied. The extraction constants ( K _ex) were determined for the ion associates of AuX^−_4 with Q^+ between an aqueous phase and several organic phases (chloroform (CF), chlorobenzene (Cl-B), benzene (B), toluene (T) and carbon tetrachloride (CTC)). The extractability of AuX^−_4 was in the order AuBr^−_4 >AuCl^−_4; the difference in log K _ex between tetrachloroaurate(III) and tetrabromoaurate(III) was about 1.16 on the average. Among the ion associates examined, the extractability of the extracting solvent was generally in the order CF>Cl-B>B>T>CTC; the differences in log K _ex between two successive solvents in this order were about 0.26,0.40, 0.09 and 0.10 on the average. The contribution of a methylene group in Q* to log K _ex was about 0.5 on the average. From the obtained extraction constants, possible extraction systems for the spectrophotometry of gold are predicted: tetrabutylammonium cation·AuCl^−_4-chloroform, tetraamylammonium cation·AuCl^−_4-chloroform, tetra-butylammonium cation-AuBr^−_4-chloroform, tetrabutylammonium cation-AuBr^−_4-chlorobenzene and tetraamylammonium cation·AuCl^−_4-benzene.