At the recent ‘Scale Up of Chemical Processes Conference’ in Baveno, Italy, Wim Dermaut from Agfa presented some case studies where problems have occurred as a result of reactive chemicals present in waste streams. In the first case study a drum containing a waste stream including diethylhydroxylamine exploded. The most likely cause was caustic present in the empty drum which initially raised the temperature of the waste to a temperature that interaction with Zn led to the runaway reaction (the waste drum was galvanized). Interestingly the supplier of diethylhydroxylamine maintained that it was safe as they only saw an endotherm in the DSC, whereas Agfa’s own studies showed an event with an onset at 105°C with a very rapid decomposition. The key difference was that the supplier had carried out their DSC run with an open cell.

In the second case study a drum containing waste from an isocyanate exploded. The issue in this case was the safety data sheet for one of the starting materials which described the compound as “Hexamethylene-1,6-diisocyanate Homopolymer”. It was in fact a diisocyanate and not a “Homopolymer” and so would react with any water to generate CO2.