Liquid-liquid distribution of ion associates of tetrabromoindate(III) with quaternary ammonium counter ions

Abstract

The solvent extraction of an ion associate of tetrabromoindate(III) ion, InBr − 4, with quaternary ammonium cations (Q +) has been studied. The extraction constant ( K ex) were determined for the ion associates of InBr − 4 with Q + between an aqueous phase and several organic phases (chloroform, chlorobenzene, benzene and toluene). A linear relationship was found between log K ex and the total number of carbon atoms in Q +; from the slope of the lines, the contribution of a methylene group to log K ex was calculated to be 0.91 for the chloroform extraction system and 0.52 for the other extraction systems. The extractability with alkyltrimethylammonium cations was larger than that with symmetrical tetraalkylammonium cations and the mean difference in log K ex for two cations (one of each type) with the same number of carbon atoms was about 1.3. From the extraction constant obtained, the extractability of InBr − 4 among metal-halogeno complex anions was in the order TlBr − 4 > BiI − 4 > AuBr − 4 > AuCl − 4 > TlCl − 4 > InBr − 4 > CuCl − 2.