To investigate the extraction characteristics of equilibrium and kinetics in the extraction of copper by ketoaldehyde-chloroform, 5-methyl-3-one-hexanal was synthesized as a chelating extractant of ketoaldehyde from ethyl formate and methylisobutylketone with sodium amide. The equilibrium constants such as the dissociation constant and the partition with sodium amide. The equilibrium constants such as the dissociation constant and the partition coefficients of ketoaldehyde, the stability constant and the partition coefficient of copper complex, and the overall equilibrium constant in the extraction of copper were determined. The effects of the concentration of hydrogen and copper ion, and of ketoaldehyde on the initial rate of extraction were examined. Percent extraction of copper by ketoaldehyde was higher than 90%, and selective extraction of copper from Zn-Cu-Cd mixture was possible. The equilibrium reaction was found to be M²⁺+2HR=MR₂+2H⁺ with the extracted species of MR₂. The experimental equation of extraction rate was ex-pressed as R=k C_HR(C_M/C_H)^0.5.