Abstract: 5-Heptyl-2-hydroxybenzaldoximes in which the heptyl group is attached to the benzene ring through a tertiary carbon atom and particularly mixtures of such aldoximes are effective as extractants for metals such as copper from aqueous solutions. These aldoximes have a more rapid rate of metal transfer from aqueous to organic phase, and vice versa, than other alkylhydroxybenzaldoximes. The benzaldoximes may be prepared from the corresponding aldehydes by reaction with hydroxylamine.

Abstract: Salicylaldoximes having a total of at least three alkyl carbon atoms contained in one or more nuclear substituents are used to extract metals from aqueous solutions of their salts as complex compounds soluble in water-immiscible organic solvents. The salicylaldoximes are prepared from the corresponding salicylaldehydes by reaction with hydroxylamine.

Abstract: Quinoline-2-carboxylic acids having in the 4-position a halogen atom or an optionally substituted hydrocarbyl group attached through an oxygen atom, optionally substituted by a hydrocarbyl group in the 3 position and optionally substituted in any of the 5, 6, 7 and 8 positions by halogen atoms, nitro or cyano groups, or optionally substituted hydrocarbyl groups each attained directly or through an oxygen atom, and containing in the substituents in the 3, 4, 5, 6, 7 and 8 positions a total of at least 3 carbon atoms form complexes with metals, especially copper. These complexes may be extracted by organic solvents from aqueous solutions of metal salts treated with the quinoline-2-carboxylic acids.