Thermal Stability, OREOS+ Explosive Hazard Assessment, and Maximum Safe Storage Temperature of Cyclic Hypervalent Iodine (λ-3-Iodane)-Based Reagents

A set of 28 cyclic hypervalent iodine (λ-3-iodane)-based reagents were systematically investigated with respect to thermal stability, possible explosive properties (OREOS+ criteria), and their maximum safe storage temperature in a 60 L drum commonly used in the chemical industry. Differential scanning calorimetry was used as a powerful and safe screening tool for this study. The stability of these compounds strongly depends on their substitution patterns, and it was found that, in general, dimethyl-benziodoxoles are less stable compared to bis(trifluoromethyl)-benziodoxoles. The highest exothermic decomposition energies were measured when a nitrooxy- or an azido-group is attached to the iodine, and also other groups like cyano-, acetoxy-, hydroxy-, or ethynyl lead to a huge exothermic event with more than (exo) 1000 J/g. For all of the investigated compounds, except one, an autocatalytic decomposition behavior can be suspected, which, in some cases, could lead to a safety critical situation at industrial storage conditions. Furthermore, for the majority of compounds, the OREOS+ explosion hazard ranking is HIGH on a 30 kg scale.