THERMAL-STABILITY OF DITHIOCARBAMATES DERIVED FROM ALPHA-AMINO-ACIDS WITH DIFFERENT METAL-IONS

The thermal stability of compounds formed by dithiocarbamates prepared from several amino acids (glycine, alanine, alpha-aminobutyric acid, norvaline, valine, norleucine, isoleucine) with Ba2+, Pb2+, Cd2+, Mo4 and Mo5+ has been studied. Owing to its larger ionic character, the b arium derivatives decompose at higher temperatures than the other comp ounds. In general terms, the stability decreases as the molecular weig ht increases. In all cases, the first step corresponds to dehydration, followed by decarboxylation and pyrolysis of the organic chain. The f inal residues have been identified by X-ray powder diffraction as oxid es, sulphates and oxosulphates.