Lead, cadmium, and zinc bis(diethyldithiocarbamate) and diethyldithiocarbamic acid as reagents for liquid-liquid extraction

Abstract

The extraction constants of Pb(DDC)₂, Cd(DDC)₂, Zn-(DDC)₂—where DDC is used to denote the diethyldithiocarbamate anion—were determined for the system H₂O/CHCI₃; log Km was found to be 7.94±0.09, 5.77±0.05, 2.39±0.02. Solutions of Cd(DDC)₂ and Zn(DDC)₂ in CHCI₃ were shown to be stable for at least 40 days. When solutions of Cd(DDC)₂, Zn(DDC)₂, or HDDC as reagents in CHCI₃ were used to extract acid aqueous solutions, their titer deteriorated as a function of pH and time; however, this deterioration is much less rapid than the destruction of a solution of NaDDC. The title compounds therefore can be considered suitable reagents for extractions from acid aqueous solutions.