Tuesday, August 25, 2015

Bleg: destroying 25 grams of AIBN

From the inbox, a darn good question - how do you get rid of 25 grams of AIBN that needs to be disposed?

Any ideas? I would usually recommend that people look in Prudent Practices in the Laboratory, but that doesn't offer any suggestions. 

14 comments:

  1. I had a quick look in "Destroying hazardous chemicals in the laboratory" but there is no entry for AIBN (or any related compounds).

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  2. Step one: take some organic solvent, i.e. condensates from rotovap receiving flask, open the old 25g AIBN bottle (wear face shield), pour the shitty solvent in, stir occasionally with a spatula. Step two: pour the whole damn thing into a large waste barrel that already has some waste in it. Wash down the funnel with some additional waste solvent. AIBN is shock sensitive only when dry. It will gradually decompose in solution over few days, evolving few grams of N2...

    I would not do this with a 25 kilo drum, but 25g does not scare me.

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  3. I haven't DONE it, and I wouldn't do it at a full 25 gram scale on the first try, but I'd guess that Fenton chemistry would work to decompose AIBN.

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  4. I was just tasked with getting rid of about 100 g of the stuff. After checking all the usual resources, I concluded the most prudent course of action was to just call clean harbors and let them deal with it. Sure, that quantity is *probably* OK to go into the organic waste drum as long as it's wetted. But why chance it?

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  5. If no certified disposal company was available, I'd dissolve small batches (2 g) in toluene, add NBS and heat it up. Probably the most expensive way to produce bromotoluene...

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  6. • Saturated aqueous solution of sodium dithionite, rigorously stirred, chilled to 0°C in a properly working fume hood with blast shield.
    • AIBN in methanol, slowly added (3 drops per minute) via funnel with stopcock or cannula.
    • After addition of AIBN, allow reaction to proceed at 0 °C for at least 1 hour. Dithionite should reduce diazo to hydrazide.
    • While still vigorously stirred at 0 °C, slowly add saturated solution of cupric sulfate to sequester cyano species.
    • Allow the reaction mixture to warm to ambient temperature over at least 1 hour. Dispose in heavy metal aqueous waste.

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    Replies
    1. Does this method have a workable/relevant citation? Might be useful for our correspondent.

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  7. @CJ

    Sorry, this method was something improvised back in my grad school group. I haven't done it in a while.
    It served as an alternative to using smelly thiols or massive amounts of stannous chloride (both of which reduce diazo).
    AIBN is recrystallized from methanol anyway, plus methanol serves as a proton source to intercept the hydrazide.
    The postgraduate side of me agrees with MA at 8:14 AM. If you can afford proper waste disposal, use it.

    Otherwise, another cheap option is a slurry of zinc powder in ammonium chloride. Just Google Scholar Search zinc reduction of diazo.
    In case any adventitious cyanide is generated, it will form a strong complex with zinc(II). Plus the ammonia will keep the system buffered.
    Again, the resultant products should still go into heavy metal aqueous waste. Sorry that I can't provide more details.

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  8. Find a polymer chemist in need. It's a terrific thermal initiator.

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    1. Hah, I remember late 2011 when I ordered AMBN to get started with some polymerizations in my company. I'm in Canada, and at the time I couldn't buy AIBN or AMBN from sigma. (I can't remember why.) We bought a "sample size" of something like 300 grams (if I remember right) from the manufacturer. Each dispersion polymerization only requires 0.25 g. And even better, in grad school my RAFT polymerizations needed maybe 5-50 mg.

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  9. Find a local, domestic CRO willing to take some of your excess reagents off your hands, and give them the bottle as an extra freebie.

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  10. Auntie MarkovnikovAugust 27, 2015 at 12:25 PM

    AIBN is also known as Vazo 67. The 67 comes from the fact that it's 10 hour half life occurs at 67 C. So, you could put in for example toluene and reflux it for a few hours to kill it.

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    1. Honored that you're commenting here, Auntie.

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  11. Azo's are flammable, reactive solids, and can undergo self-acclerated decomposition at elevated temperatures. For AIBN, the danger point is about 50C. Heating these guys up in the presence of a flammable solvent--especially one with a boiling point greater than 50C, is a recipe for disaster. Not to mention that one of the degradation products of AIBN is a toxic compound known as tetramethylsuccinonitrile, TMSN. You don't want to mess with TMSN.

    Find a local incinerator and let them do the job the correct way: burn the AIBN. If you can't do that, run a waste polymerization with the AIBN and then dispose of the polymer according to local regulations.

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