LiAlH4 fire after pressure pushes out syringe needle


LiAlH4 fire after pressure pushes out syringe needle

Wednesday, September 2, 2015


A LiAlH4 reduction of a nitro in ether was being performed under N2 at -78 degrees Celsius. When the bath was removed to allow the reaction to warm to room temperature, a pressure build up caused a needle to clog and the septum of the round bottom flask was ejected due to the high pressure. A fire formed above the reaction vessel lasting ∼ 2 minutes. The fire was observed by another researcher who alerted the rest of the lab and acquired the fire extinguisher in case the fire spread or intensified.


  • Using the correct glassware and being hooked up to a bubbler. Many groups do the "quick and dirty" N2 work with needles thru septa into flasks. This is OK for a lot of things, but it is certainly a really really bad idea whenever you're working with pyrophorics.

  • Keep the reaction at -78 degrees Celsius for a longer period of time. When warming up a reaction to room temperature, slowlyincreases the temperature from -78 to -35 degrees Celsius as this will greatly reduce the chances of run away reactions.

  • If you do see a fire please know that there's no punishment that comes with using a fire extinguisher to put out a fire!!