In a study of the relationship between structure and efficiency towards recovery of copper(H) by chelation/solvent extraction, a series of homologous aldoximes has been synthesised from natural phenolic lipidic, and fatty lipidic renewable sources, for comparison with commercial reagents prepared from petrochemical sources. From cardanol, in technical cashew nut-shell liquid, isoanacardic aldoxime, [2-hydroxy-4-pentadec(en)yl]aldoxime, and from the natural phenolic lipid, anacardic acid, the isomer, 2-hydoxy-6-pentadec(en)ylaldoxime, have been synthesised. A C-11 analogue of anacardic aldoxime from Anacardium giganteum has been prepared. The isomeric n-octyl aldoximes have been synthesised, the o- and p-isomers from the readily available fatty acid n-octanoic acid and the m-isomer from cardanol. Related m-aldoximes have been prepared from the ketonic intermediates methyl isoamyl and methyl amyl ketones. The solvent extraction properties for copper(II) of the synthesised aldoximes have been compared with those of a current commercial reagent, 2-hydroxy-5-t-nonylbenzaldoxime (Acorga 5100, Cytec), and two former extractants, 2-hydroxy-5-t-nonylacetophenone ketoxime (SME 529, Shell) and 2-hydroxy-5-t-nonylbenzophenone ketoxime (LIX 65N, Henkel). All the aldoximes possessed useful properties in extraction efficiency, notably the isoanacardic and the C-8 aldoximes with the C-8 o-isomer, 2-hydroxy-3-n-octylbenzaldoxime, exhibited optimal extraction, stripping and phase separation characteristics. (c) 2005 Society of Chemical Industry.