[Organishe]

I was doing a palladium catalyzed hydrosilation with TMS protected allyl alcohol and upon heating to reflux, the reaction mixture began vigorously boiling, and blew the reflux condenser off the flask, filling the hood with a wonderful mixture of the protected alcohol and my silane. My story would be much more impressive if the mixture had ignited, but thankfully it didn't. Also to great fortune, I was the only one working in the hood at the time, and the sash was down.  The room still quickly filled with the vapors, and again, fortunately, there were not many people in the room at the time.  I am told that the look on my face as I bolted toward the fire extinguisher was a priceless ghost-white. I am very glad i didn't have to use it!

Thing I was most pissed about was that I wasted a couple hundred bucks in materials (I worked for a small time guy, and the materials nearly blew my entire research fund for the summer). 

Things I learned:
1. Scale up scares me. Reaction worked fine on 50 mg scale, so it should be fine on all, right? Not necessarily.
2. The paper even said this could happen, and I didn't really take adequate precaution against it, because they only said it occurred when "adding additional Pd catalyst upon a failed reaction initiation". If someone says something exploded in a paper, they probably aren't pulling your leg.
3. Clear your hood of nasty stuff when running a reaction with extra danger, perhaps. A 4L jug of a flammable solvent in the hood + ignition could have been the end of me and my labmates.

The last thing I have to say is about a dumb mistake that I made, which I think led to this whole thing. The procedure which I based my reaction on did this on a huge scale (several liters) and used approximately 1g of Pd-C Catalyst. Stoichiometric scale-down for my reaction put me at sub-milligram amounts of catalyst. Since I didn't believe I could accurately weigh out this amount, I just plopped in a meg or 2. In retrospect I realize I used about 10 times too much catalyst, so perhaps upon reaching initiation into the catalytic cycle, it went very vigorously due the the massive catalytic availablilty. (i dunno, just an idea. For all I know, it could have nothing to do with this)

[english]

The first one got my attention rather quickly:

An Aroostook County, Maine, teacher elects to dispose of one quarter pound of potassium metal by attaching the container to a long wooden stick and dumping it into a metal waste basket full of water in the school parking lot. The resulting explosion sends shrapnel flying and does minor damage to cars in the parking lot. Miraculously no one was injured. (Personal communication, July, 1988)



Wow that was just....stupid. 

[xiankai]

how about forgetfulness, absent-mindedness, and ignorance of the presence of water?

[jdurg]

I nearly had another accident to add to my list this past weekend.  I went to visit a friend of mine who is also pretty big into the elements and chemistry and we decided to do a reaction to reduce silicon dioxide into elemental amorphous silicon.  We had everything we needed but the SiO2.  Instead, we had silicic acid which is easily converted into SiO2 by simple heating.  So we spent some time heating up the Silicic Acid and turning it into SiO2.

The SiO2 was then mixed very intimately with some fine magnesium powder.  This reaction is sort of like a thermite reaction but MUCH less intense.  In our test tube we heated the reaction up and it immediately started glowing a cherry red color and you could tell that the reaction was proceeding.  The tube was set aside for a while to let the reaction proceed and the products were eventually dumped out of the tube.  We wound up with this mixture of brown powder and deep blue/brown clumps.  This is a mixture of elemental Si, Mg, MgO, and some MgSi.  Each of the products will dissolve in HCl except for Si so we had a way to purify it.

We started out by taking the tube the reaction took place in and adding 12M HCl.  It started to pop and fizz a bit as unreacted Mg dissolved and the MgSi formed SiH4 which immediately ignited.  The brown amorphous Si that was left was filtered out.  The test tube was then filled up again with 12M HCl and we added little bits of our reaction product.  It would pop and fizz a bit as it reacted and the silicon again just settled to the bottom.  We had a bunch left over so we decided to scale up the reaction.  UH-OH.  A relatively large amount of the blue/brown powder was put into the tube and it immediately went KA-BOOM like a shotgun going off as a massive amount of Silane formed and ignited as well as the hydrogen from the unreacted magnesium.  My ears were ringing for a good four or five hours afterward.  The odd thing was, there was almost no flame to be seen.  It just made the loud boom and that was it.  Really scared the crap out of me.   

[Bakegaku]

how about forgetfulness, absent-mindedness, and ignorance of the presence of water?

Considering he distanced himself from the site with a long wooden pole and the trash can was "full" of water, I'm pretty sure he knew the water was in the trash can when he dropped the potassium in.... he just wanted to have some ridiculous reckless fun.

It's amazing how ridiculous some people can be in their pranks and disregard for blatant labroom safety.  Who would put sulphuric acid in a milk carton?  potassium dichromate in a soda bottle!? Clean a toilet with sulphuric acid!?!?

Natural selection is our only hope 

[mike]

Some more interesting stories of accidents

http://www.users.on.net/~philipc/chem.html#jan97

[mike]

So maybe not specifically a chemistry accident but how is this guy?

http://www.smh.com.au/news/world/bum-cracker-stunt-backfires/2006/11/10/1162661861817.html

[Dan]

^ natural selection in action (well, almost).

[constant thinker]

Hopefully he won't be able to reproduce. Although that's hilarious. It's unbelievably stupid. Good find mike.