Extraction and separation of germanium(IV) with 4-pyridone derivatives

Extraction of germanium(IV) from aqueous hydrochloric, sulphuric and phosphoric acid solutions with 3-hydroxy-2-methyl- 1-phenyl-4-pyridone (HX) and 3-hydroxy-2-methyl-1-(4-tolyl)-4-pyridon (HY) dissolved in chloroform was studied. Extraction with HX took place in the acidity range 1-3 M H2SO4 or 0.5-9.5 M HCl and that with KY in the range 0.5-5 M H2SO4 or 0.2-9.5 M HCl. Separation of germanium(III) from a large excess of zinc(II), arsenic(III) and gallium(III) by extraction with HX and HY was simple and fast. Formation of a Ge-IV-HX(HY) complex from sulphuric acid solution was applicable for spectrophotometric determination of germanium(IV) in the organic phase at the maximum absorption at 299 nm. Extraction of germanium(IV) with chloroform, in the absence of HX or HY, from hydrochloric and sulphuric acid solutions, in dependence on acid concentration and on addition of lithium chloride, was also studied.