EXTRACTION OF DITHIOCARBAMATE CHELATES OF NI(II), CU(II), ZN(II)

Extraction has been investigated of chelates of alkali salts of dithiocarbamic (DTC) acids derived from (R-) dimethyl-, diethyl-, dipropyl-, diisopropyl-, dibutyl-, diisobutyl-, dipentyl-, and dihexylamine, piperidine, and morpholine with Ni(II), Cu(II), and Zn(II) from aqueous solutions of various pH values into chloroform for various time intervals. The optimum conditions have been determined for the maximum extraction yields of the metal connected with the minimum extraction yields of excess DTC ligand. The extraction of DTC chelates of Ni(II), Cu(II), and Zn(II) is best accomplished in a reaction period of 4.5 min in strong acid region (Ni, Cu) or in alkaline region with buffers of pH 8.5-9.0 (Zn). The advantage of DTC as compared with many other reagents lies in the possibility of quantitative extraction of Ni(II) and Cu(II) from strong acid media since in this region the excess DTC ligand is completely decomposed to carbon disulfide and amine in short time, and thus it does not interfere with the subsequent spectrophotometric determination.