The hydrolysis of ethylene diisothiuronium bromide in the presence of Ni(II), Cu(II) and Zn(II)

Abstract

The hydrolysis of ethylene diisothiuronium bromide in cold ammoniacal medium in the presence of metal ion [Ni(II), Cu(II) and Zn(II)] gives a mixture of metal ethanedithiolate and metal complex of unhydrolyzed ligand, the relative proportion of which increases in the series Cu < Ni < Zn. This unhydrolyzed ligand has been shown by infrared and mass spectral techniques not to be unhydrolyzed EDIB itself but a mixture of its N-amidino and N-cyano derivatives. The series of Cu < Ni < Zn is explained on the basis of the relative catalytic effects of the metal ions on the hydrolysis of EDIB to ethanedithiol at the expense of the formation reactions of the N-amido and N-cyano derivatives, which are independent of the metal ion. Full hydrolysis of these mixtures to metal ethanedithiolates is promoted by heating in water for nickel and copper or in alkali for zinc.