Solvent Extraction of Silver(I) and Palladium(II) Ions with Ketone Derivative of Calix[4]arene from Highly Acidic Nitrate Media

Abstract
The solvent extraction of silver (I) and palladium (II) ions with 25,26,27,28-tetrakis(acetomethoxy)-5,11,17,23-tetrakis(1,1,3,3-tetramethylbutyl)calix[4]arene (1) in chloroform from nitric acid solution was investigated. The compound 1 was capable of highly selectively extracting silver over palladium from about 1 mol dm−3 nitric acid solution and was effective in removing trace amounts of silver from a large excess of palladium. The coordination site of silver ion on 1 was also determined from the chemical shift in the 1H-NMR spectra.