USE OF DICHLOROMETHANE WITH DITHIZONE AS AN ALTERNATIVE SOLVENT TO CARBON-TETRACHLORIDE RESTRICTED BY MONTREAL PROTOCOL

The spectral characteristics of dithizone and its metal complexes were measured in dichloromethane as an alternative solvent to carbon tetra chloride which will be illegal to manufacture by the year 2000, accord ing to the revised Montreal Protocol. The extraction equilibria of its metal complexes were also reported and discussed. Dichloromethane was found to enhance the sensitivity of dithizone towards Co(II), Cu(II), Hg(II), Pb(II), Zn(II), Bi(III), Ag(I), In(III) and Tl(I). It was als o found to be a better solvent than carbon tetrachloride for the separ ation of Cd(II) from Zn(II) and for the separation of Co(II) from Ni(I I). (C) 1997 Elsevier Science B.V.