Extraction of copper from acid sulphate solutions by 2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐benzaldehyde,‐acetophenone and ‐benzophenone oximes

Abstract 2‐Hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐benzaldehyde E‐oxime (1), 2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐acetophenone E‐oxime (2) and 2‐hydroxy‐5‐(1,1,3,3‐tetramethylbutyl)‐benzophenone E‐oxime (3) were synthesized and used for copper extraction from acidic sulphate solutions. The dissociation constants of the phenolic group of the oximes and the stability constants for their complexes with copper were determined. An extraction model is discussed taking under consideration the association of the oxime and the solvation of the complex. It was found that 1 can extract copper more efficiently from acidic aqueous solutions and at a higher rate than 2 and 3. 1 is a stronger acid than 2 and 3. However, it is a weaker acid than the Z isomer of 3. The proposed model fits the experimental data well. When the oxime is used in excess, solvation of the copper complex seems probable.