Incident during bromination, due to change of raw material grade
The incident involved bromination of an aromatic compound using bromine in an organic solvent. Finely divided potassium carbonate is added to scavenge the HBr formed.
On the day of the incident fine material was not available and normal grade carbonate was used instead. The batch apparently reacted normally but on drown-out into water the vessel pressurized and black tars were ejected from the vessel. Visually there was little difference between the two materials but it is thought that the 'normal' grade was not agitated as efficiently and formed an impervious KBr layer leaving unreacted carbonate and HBr which came into contact on drown-out.