THE DECOMPOSITION OF DITHIOCARBAMATE FUNGICIDES, WITH SPECIAL REFERENCE TO THE VOLATILE PRODUCTS

Abstract

The gaseous exchange accompanying decomposition of dithiocarbamate fungicides was measured in the Warburg manometer. Sodium diethyl dithiocarbamate decomposed under slightly acid conditions, producing carbon disulphide and a salt of diethylamine. The insoluble zinc and iron salts of dimethyl dithiocarbamic acid also decomposed in a similar fashion, but no carbon disulphide was given off from the more stable copper salt of this compound. The rate of decomposition of these metallic salts fell in the following decreasing order:[Formula: see text]Disodium ethylene bis-dithiocarbamate (nabam) decomposed under slightly acid conditions to produce approximately equal volumes of hydrogen sulphide and carbon disulphide, and presumably left a residue of ethylene thiourea. In distilled water, on the other hand, nabam underwent a slow basic hydrolysis and oxidation, with absorption of approximately two volumes of oxygen, and evolution of one volume of carbon disulphide. Apparently the sulphur fraction which is evolved as hydrogen sulphide from nabam under acid conditions is, under basic conditions, oxidized in solution by atmospheric oxygen to sulphate.