Thermal analysis of thione compounds

The thermal behavior of thiourea (Tu), N-methylthiourea (MeTu), N, N-dimethylthiourea (Me₂Tu) and N, N, N, N-tetramethylthiourea (Me₄Tu) was investigated by means of conventional thermal analysis in O₂ and N₂ and IR spectroscopy of the residues on heating in air at various temperatures.At ordinary pressure, the compounds are thermally stable up to the melting points. After melting, they show high vapor pressure, combustion in O₂ atmosphere and isomerization to ammonium thiocyanate, with the exception of Me₄Tu.Financially supported by the Italian MURST.