evil_lurker
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Registered: 12-3-2005
Location: United States of Elbonia
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Mood: On the wagon again.
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Attempt at chlorination of toluene using in situ TCCA... massive runaway!
Crap!
Tried adding 500ml of toluene to 1 mole of TCCA in a flask and then slowly heating it up .
Big mistake.
Everything was ok for a while, then all of a sudden massive amounts of foaming suddenly occurred and TCCA/toluene shot out all over the place.
I killed the power, and began the process of disassembling the whole works.
Well I had my condensor and what not off, and strangely about 3 minutes later, the reaction picked up again from the remnants of what was in the
flask.
This time it spontaneously heated up and started to shoot a huge cloud of smokey toluene and TCCA vapors 3 feet up in the air! 
I thought the shit was going to blow at any second!
When the smoke stopped and everything cooled down there was this rust looking moon rock looking mess in the flask... and heard a slight tinking
sound... the flask was cracking... 
I have to go finish cleaning everythign now, hopefully my hotplate will still work... it has a nice white coating all over the outside and inside that
will be hell to get off. 
Anyways, just a warning for those that might be interested, DON'T TRY IT!
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Nicodem
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That was a very stupid thing to do, but I’m glad nothing really bad happened. Mixtures of strong oxidizers with reducing organic compounds
tend to do that. You are lucky the whole thing did not just explode considering that you used no excess of toluene.
If you wanted to chlorinate the toluene on the ring you should have used a several fold excess of toluene and an acid catalyst so that it could be
done at room temperature. If you wanted to chlorinate it on the side chain you should have also a several fold excess of toluene and a radical
initiator or sunlight or else the reaction tends to be heat controlled. And when exothermic reactions are heat controlled they tend to self sustain,
speed up and run out of control.
I guess it is not that bad after all. It could be worse and at least you learned something doing it: To keep your reactions under control.
…there is a human touch of the cultist “believer” in every theorist that he must struggle against as being
unworthy of the scientist. Some of the greatest men of science have publicly repudiated a theory which earlier they hotly defended. In this lies their
scientific temper, not in the scientific defense of the theory. - Weston La Barre (Ghost Dance, 1972)
Read the The ScienceMadness Guidelines!
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chromium
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This is why i love microscale chemistry.
[Edited on 12-7-2006 by chromium]
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evil_lurker
National Hazard
Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
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Mood: On the wagon again.
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It was a good lesson indeed... I imagine the same thing could happen with the loomis patent method as well.
Interestingly enough I attempted to do the same thing yesterday using the same proportions, except in reverse order... the TCCA was cautiously added
to boiling toluene... again some foaming upon addition, but otherwise no reaction.
It was very messy, and because of the lack of reaction of that I assumed that it would be safe to just go ahead and heat up the contents of
the flask all at once since there was essentially no reaction the last time... after an hour at full reflux in the sun only a trace of benzyl chloride
was to be had.
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ordenblitz
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Moved to the proper thread.
[Edited on 14-7-2006 by ordenblitz]
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