(41am) Thermal Hazard Evaluation and Safety Considerations for the Use of O-Benzoyl-N-Alkyl Hydroxylamines As Synthetic Reagents

Numerous synthetic methods utilize O-benzoyl-N-alkyl hydroxylamines (BzO-NR2) as electrophilic aminating reagents. The utility of BzO-NR2 reagents arises from the high energy (weak) N-O bond. It has long been understood that significant thermal hazards can be present in molecules featuring weak heteroatom-heteroatom linkages. Relevant to this study, two major industrial incidents have occurred from the production of the parent molecule hydroxyl amine. Therefore, it’s important to gather information on the thermal hazards associated with this class of reagents. The reagents were investigated using calorimetry and thermokinetic modeling. Many of the compounds demonstrated low onset temperatures by differential scanning calorimetry (DSC). The observed onset temperature was below reported operating temperatures for some synthetic methods. Variable sweep rate DSC data indicated a high probability of autocatalytic decomposition. These data were modeled using Advanced Kinetics and Technology Solutions (AKTS) Software to predict and confirm autocatalytic behavior. Finally accelerating rate calorimetry (ARC) was performed to confirm the low thermal onset and high exotherm of decomposition. Taken together, these results indicate care should be taken in the synthesis, use, transport, and storage of these reagents.