The thermal decomposition
of iminodiacetic, oxydiacetic, and thiodiacetic acids in helium atmosphere
has been studied by means of thermogravimetry (TG), differential thermal analysis
(DTA) and temperature-programmed pyrolysis directly coupled with mass spectrometry
(TPPy-MS). Evolved gas analysis (EGA) profiles of iminodiacetic and oxydiacetic
acids were obtained and compared with TG and DTA profiles.
of iminodiacetic acid forms water, CO, CO2, CH3CN,
HCN and some hydrocarbons. After water evolution a cyclic anhydride is formed,
as well as for oxydiacetic acid. Thiodiacetic acid vaporizes without decomposition.