Ionic polymerisation as a means of end-point indication in non-aqueous thermometric titrimetry. Part IX. Determination of dithiocarbamates and phosphorodithioates

Abstract

Ammonium, cadmium, bismuth, iron, lead, manganese, nickel, piperidinium and zinc dithiocarbamates and nickel and zinc phosphorodithioates have been determined in amounts down to 0.002 mmol by catalytic thermometric iodimetric titration of their solutions in dimethylformamide and acrylonitrile. The end-points in most instances correspond to the formation of polyiodides. The reaction stoicheiometries depend on the nature of the ligand as well as on the central ion. The method has been compared with aqueous iodimetry, and the results agree to within about 1%.

Solutions of dithiocarbamates and phosphorodithioates in hydrocarbon oils, used as oil additives, can be determined in concentrations down to 0.05%. High-boiling alcohols and other oil additives, including hindered phenols, diphenylamine derivatives and phenothiazine, do not interfere. The results show precisions ranging from 0.44 to 2.01%.