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

Extraction has been investigated of chelates of alkali salts of dithio carbamic (DTC) acids derived from (R-) dimethyl-, diethyl-, dipropyl-, diisopropyl-, dibutyl-, diisobutyl-, dipentyl-, and dihexyl- amine, p iperidine, and morpholine with Ni(II), Cu(II), and Zn(II) from aqueous solutions of various pH values into chloroform for various time inter vals. The optimum conditions have been determined for the maximum extr action yields of the metal connected with the minimum extraction yield s of excess DTC ligand. The extraction of DTC chelates of Ni(II), Cu(I I), 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.O (Zn). The advantage of DTC as compared with many other reagent s 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.