Excessive foam from ammonium formate

The Incident

Reactor charged with substrate + ethanol + Pd/C. Heated to 60°C and added 23 kg of ammonium formate - Batch foamed out of reactor.

Reasons

All lab records showed that the vigorous foaming was expected (with or without the substrate) at this temperature, all earlier batches had been successful, however this batch was a 25% scale up, and it appears that the vent line could not cope with the increased gas flow.

Lessons

Where there is a great gas flow, it is essential to ensure that the vent is capable of passing the gas as fast as it is liberated. Careful gas flow measurements at the laboratory stage must be made to allow safe scale up to plant.