Overheating an oil bath

Title

Overheating an oil bath

Monday, November 9, 2015

Situation

An undergraduate was setting up a simple reaction with a round bottom of water and salt that was to be heated to 30 °C. The undergraduate had only set up one other reaction in lab (but an identical reaction) and was properly trained on all lab SOPs. She was under supervision but the post-doc did not double check the temperature of the oil bath prior to the start of the reaction. Mistakenly, the oil bath was heated to 130 °C instead of 30 °C and when the round bottom was capped with a rubber septa, pressure built and the septa exploded and ended up shattering the glass covering the hood light. Since the glass is safety glass, none fell to the ground but upon touching the glass to wipe off the water and salt, some started to fall. There was no injury or safety hazard other than broken glass.

Suggestions

• New students should ALWAYS be closely monitored when setting up reactions

• Flasks should never be in a closed system without a vent. Air sensitive reactions should be hooked up to a nitrogen bubbler to regulate pressure and other reactions should always have a vent via a needle in the septa.

• Temperatures should always be double checked prior to heating any reaction.