[Mitch]

"We went out to drink a coffee, since nothing happened in the first half hour. When we got back to the lab the flask was as like seen on the pictures. No solvent left in the flask, some carbonized burns at the neck of the flask and most of my compound around the stirrer. "
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Full story at: http://labphoto.tumblr.com/post/98743432043/an-open-air-oxidatation-was-made-with-a-chiral

[discodermolide]

OOPS, just as well is was not very large scale!
Accumulation and a runaway reaction.

[Mitch]

Fortunately, for them it wasn't that flammable.

[Guitarmaniac86]

I dont have pictures but I managed to colour my white fumehood yellow when I was cleaning a large piece of glassware with concentrated nitric acid forgetting that I had a solution of trityl hydroxide in toluene in it. I thought I had rinsed it out and there was only water in it...

It got hot very quick, evolved a dark brown gas that fumed violently and the solution explosively boiled coating my nice fumehood with a yellow sticky compound. I still havent managed to wash it off... Acetone helped a bit but I have resigned myself to a yellow fumehood.

(I've done the same thing with diphenylcarbamoyl chloride... I double check now so I dont do it again).

[Babcock_Hall]

I was doing some phosphorus chemistry last year involving tert-butyl esters of phosphonates.  The reaction unexpectedly got hot while I was weighing the flask.  The resulting material was a yellow-orange solid that was obviously not my product.  I have two theories about what might have happened.  One is loss of the tert-butyl groups due to an unexpected acidic impurity.  The other is that I had used a small volume of THF that might have been old and perhaps some peroxide-based reaction was going on.  I will try to avoid a repeat of this at all costs.