A Grignard was ran a number of times at 500 ml scale without incident, this was a low temperature (-65°C) preparation in diethyl ether.
When the experiment was scaled up to 2 litres, there was a violent runaway, the reaction flask was completely destroyed, and considerable damage was done to the fume cupboard
The Grignard had a particularly low starting volume, there was poor control of the temperature, which in turn led to accumulation of reagent. The explosion was due to the high diethyl ether vapour pressure.
An alternative route was developed